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Osunla A, Oloye F, Kayode A, Femi-Oloye O, Okiti A, Servos M, Giesy J. The Slow Pandemic: Emergence of Antimicrobial Resistance in the Postadvent of SARS-CoV-2 Pandemic. Glob Health Epidemiol Genom 2025; 2025:3172234. [PMID: 40271530 PMCID: PMC12017956 DOI: 10.1155/ghe3/3172234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Accepted: 11/29/2024] [Indexed: 04/25/2025] Open
Abstract
Background: The unprecedented outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has dramatically changed the global approach to public health, emphasizing the importance of measures to control and prevent infections. In response to the COVID-19 crisis, stringent hygiene practices and surface disinfection have become the norm, with an unprecedented surge in the use of disinfectants and antiseptics (DAs). Main Text: While these measures have been crucial in curbing the spread of the virus, an emerging concern has taken center stage: the potential impact of the prolonged and widespread use of antimicrobial compounds in these products on the development of antibiotic resistance. Antimicrobial resistance (AMR) has long been recognized as one of the most pressing global health threats. Quaternary ammonium compounds (QAC) such as benzalkonium chloride, benzethonium chloride, and cetylpyridinium chloride, which are extensively used in DAs formulations, have gained less attention in the context of AMR. Conclusion: A high abundance of QACs was detected in wastewater, and certain bacteria such as Pseudomonas aeruginosa, Acinetobacter baumannii, and Enterococcus species developed resistance to these compounds over time. We analyzed the available evidence from the scientific literature, examining the presence and concentrations of QACs in different water sources, and their resistance mechanisms. This review aimed to shed light on the multifaceted challenges that arise from the dual battle against the COVID-19 pandemic and the ongoing global fight against AMR.
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Affiliation(s)
- Ayodeji Osunla
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Microbiology, Adekunle Ajasin University, Akungba-Akoko, Ondo, Nigeria
| | - Femi Oloye
- Division of Physical and Computational Sciences, University of Pittsburgh, Bradford, Pennsylvania, USA
| | - Adeoye Kayode
- Department of Biochemistry, Genetics, and Microbiology, Forestry and Agricultural Biotechnology Institute, University of Pretoria, Pretoria, South Africa
| | - Oluwabunmi Femi-Oloye
- Division of Physical and Computational Sciences, University of Pittsburgh, Bradford, Pennsylvania, USA
| | - Ayomide Okiti
- Department of Microbiology, Adekunle Ajasin University, Akungba-Akoko, Ondo, Nigeria
| | - Mark Servos
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - John Giesy
- Toxicology Centre, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
- Department of Integrative Biology and Centre for Integrative Toxicology, Michigan State University, East Lansing, Michigan, USA
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Roila R, Valiani A, Servili M, Ranucci D, Galarini R, Ortenzi R, Primavilla S, Branciari R. Control of Listeria monocytogenes on Frankfurters by Surface Treatment with Olive Mill Wastewater Polyphenolic Extract. Foods 2025; 14:774. [PMID: 40077477 PMCID: PMC11899662 DOI: 10.3390/foods14050774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2025] [Revised: 02/15/2025] [Accepted: 02/22/2025] [Indexed: 03/14/2025] Open
Abstract
Listeria monocytogenes (LM) is a frequent post-process contaminant in meat products. This study aimed to investigate the antilisterial effectiveness of post-process antimicrobial treatments employing olive mill wastewater polyphenolic extract (PE) in commercially manufactured frankfurters. Frankfurters were inoculated on the surface with a three-strain LM mixture (~102 CFU/g), treated on the surface with PE in a 2-fold series of concentrations (PM, 2PM, 4PM) and a control group (CTR) of PE-untreated samples. Then, the frankfurters were vacuum-packed and stored at 4 °C for 28 days. Samples were examined on days 0, 7, 14, 21, and 28 for LM count, in silico growth modeling, and impacts on pH, water activity (aw), and sensory characteristics. From T(time) 7, the PE treatment showed a significant effect on LM growth, registering maximum Δ values between CTR and 4PM of 3.19, 4.86, 4.59, 4.39 at T7, T14, T21, T28, respectively. Minimum effect was attributable to PM treatment with Δ values (CTR versus PM) of 2.07, 2.52, 1.14, 0.65 at T7, T14, T21, T28, respectively. No significant changes occurred in pH (average 6 at T0 and 5.9 at T28), aw (average 0.978 at T0 and 0.968 at T28), nor in sensory profile (p > 0.05). These findings suggest that PE is an effective natural antimicrobial, offering a promising approach to enhancing food safety and extending shelf life in meat products.
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Affiliation(s)
- Rossana Roila
- Department of Veterinary Medicine, University of Perugia, Via San Costanzo 4, 06121 Perugia, Italy; (R.R.); (R.B.)
| | - Andrea Valiani
- Istituto Zooprofilattico Sperimentale dell’ Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (R.G.); (R.O.); (S.P.)
| | - Maurizio Servili
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Via S. Costanzo, 06126 Perugia, Italy;
| | - David Ranucci
- Department of Veterinary Medicine, University of Perugia, Via San Costanzo 4, 06121 Perugia, Italy; (R.R.); (R.B.)
| | - Roberta Galarini
- Istituto Zooprofilattico Sperimentale dell’ Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (R.G.); (R.O.); (S.P.)
| | - Roberta Ortenzi
- Istituto Zooprofilattico Sperimentale dell’ Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (R.G.); (R.O.); (S.P.)
| | - Sara Primavilla
- Istituto Zooprofilattico Sperimentale dell’ Umbria e delle Marche “Togo Rosati”, Via Salvemini 1, 06126 Perugia, Italy; (R.G.); (R.O.); (S.P.)
| | - Raffaella Branciari
- Department of Veterinary Medicine, University of Perugia, Via San Costanzo 4, 06121 Perugia, Italy; (R.R.); (R.B.)
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Zhang J, Li T, Tao S, Shen M. Microplastic pollution interaction with disinfectant resistance genes: research progress, environmental impacts, and potential threats. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024; 31:16241-16255. [PMID: 38340302 DOI: 10.1007/s11356-024-32225-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Accepted: 01/23/2024] [Indexed: 02/12/2024]
Abstract
The consumption of disposable plastic products and disinfectants has surged during the global COVID-19 pandemic, as they play a vital role in effectively preventing and controlling the spread of the virus. However, microplastic pollution and the excessive or improper use of disinfectants contribute to the increased environmental tolerance of microorganisms. Microplastics play a crucial role as vectors for microorganisms and plankton, facilitating energy transfer and horizontal gene exchange. The increase in the use of disinfectants has become a driving force for the growth of disinfectant resistant bacteria (DRB). A large number of microorganisms can have intense gene exchange, such as plasmid loss and capture, phage transduction, and cell fusion. The reproduction and diffusion rate of DRB in the environment is significantly higher than that of ordinary microorganisms, which will greatly increase the environmental tolerance of DRB. Unfortunately, there is still a huge knowledge gap in the interaction between microplastics and disinfectant resistance genes (DRGs). Accordingly, it is critical to comprehensively summarize the formation and transmission routes of DRGs on microplastics to address the problem. This paper systematically analyzed the process and mechanisms of DRGs formed by microbes. The interaction between microplastics and DRGs and the contribution of microplastic on the diffusion and spread of DRGs were expounded. The potential threats to the ecological environment and human health were also discussed. Additionally, some challenges and future priorities were also proposed with a view to providing useful basis for further research.
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Affiliation(s)
- Jiahao Zhang
- School of Energy and Environment, Anhui University of Technology, Maanshan, Anhui, 243002, People's Republic of China
| | - Tianhao Li
- School of Energy and Environment, Anhui University of Technology, Maanshan, Anhui, 243002, People's Republic of China
| | - Shiyu Tao
- School of Energy and Environment, Anhui University of Technology, Maanshan, Anhui, 243002, People's Republic of China
| | - Maocai Shen
- School of Energy and Environment, Anhui University of Technology, Maanshan, Anhui, 243002, People's Republic of China.
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4
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Schulz LM, Dreier F, de Sousa Miranda LM, Rismondo J. Adaptation mechanisms of Listeria monocytogenes to quaternary ammonium compounds. Microbiol Spectr 2023; 11:e0144123. [PMID: 37695041 PMCID: PMC10580936 DOI: 10.1128/spectrum.01441-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 07/13/2023] [Indexed: 09/12/2023] Open
Abstract
Listeria monocytogenes is ubiquitously found in nature and can easily enter food-processing facilities due to contaminations of raw materials. Several countermeasures are used to combat contamination of food products, for instance, the use of disinfectants that contain quaternary ammonium compounds, such as benzalkonium chloride (BAC) and cetyltrimethylammonium bromide (CTAB). In this study, we assessed the potential of the commonly used wild-type strain EGD-e to adapt to BAC and CTAB under laboratory growth conditions. All BAC-tolerant suppressors exclusively carried mutations in fepR, encoding a TetR-like transcriptional regulator, or its promoter region, likely resulting in the overproduction of the efflux pump FepA. In contrast, CTAB tolerance was associated with mutations in sugR, which regulates the expression of the efflux pumps SugE1 and SugE2. L. monocytogenes strains lacking either FepA or SugE1/2 could still acquire tolerance toward BAC and CTAB. Genomic analysis revealed that the overproduction of the remaining efflux system could compensate for the deleted one, and even in the absence of both efflux systems, tolerant strains could be isolated, which all carried mutations in the diacylglycerol kinase-encoding gene lmo1753 (dgkB). DgkB converts diacylglycerol to phosphatidic acid, which is subsequently reused for the synthesis of phospholipids, suggesting that alterations in membrane composition could be the third adaptation mechanism. IMPORTANCE Survival and proliferation of Listeria monocytogenes in the food industry are ongoing concerns, and while there are various countermeasures to combat contamination of food products, the pathogen still successfully manages to withstand the harsh conditions present in food-processing facilities, resulting in reoccurring outbreaks, subsequent infection, and disease. To counteract the spread of L. monocytogenes, it is crucial to understand and elucidate the underlying mechanism that permits their successful evasion. We present various adaptation mechanisms of L. monocytogenes to withstand two important quaternary ammonium compounds.
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Affiliation(s)
- Lisa Maria Schulz
- Department of General Microbiology, Institute of Microbiology and Genetics, GZMB, Georg-August University Göttingen, Göttingen, Germany
| | - Fabienne Dreier
- Department of General Microbiology, Institute of Microbiology and Genetics, GZMB, Georg-August University Göttingen, Göttingen, Germany
| | - Lisa Marie de Sousa Miranda
- Department of General Microbiology, Institute of Microbiology and Genetics, GZMB, Georg-August University Göttingen, Göttingen, Germany
| | - Jeanine Rismondo
- Department of General Microbiology, Institute of Microbiology and Genetics, GZMB, Georg-August University Göttingen, Göttingen, Germany
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5
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Lakicevic B, Jankovic V, Pietzka A, Ruppitsch W. Wholegenome sequencing as the gold standard approach for control of Listeria monocytogenes in the food chain. J Food Prot 2023; 86:100003. [PMID: 36916580 DOI: 10.1016/j.jfp.2022.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 10/05/2022] [Accepted: 10/19/2022] [Indexed: 12/23/2022]
Abstract
Listeria monocytogenes has been implicated in numerous outbreaks and related deaths of listeriosis. In food production, L. monocytogenes occurs in raw food material and above all, through postprocessing contamination. The use of next-generation sequencing technologies such as whole-genome sequencing (WGS) facilitates foodborne outbreak investigations, pathogen source tracking and tracing geographic distributions of different clonal complexes, routine microbiological/epidemiological surveillance of listeriosis, and quantitative microbial risk assessment. WGS can also be used to predict various genetic traits related to virulence, stress, or antimicrobial resistance, which can be of great benefit for improving food safety management as well as public health.
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Affiliation(s)
- Brankica Lakicevic
- Department for Microbiological and Molecular-biological Testing, Institute of Meat Hygiene and Technology, Belgrade, Serbia.
| | - Vesna Jankovic
- Department for Microbiological and Molecular-biological Testing, Institute of Meat Hygiene and Technology, Belgrade, Serbia
| | - Ariane Pietzka
- Institute of Medical Microbiology and Hygiene/National Reference Laboratory for Listeria Division for Public Health, Austrian Agency for Health and Food Safety, Graz, Austria
| | - Werner Ruppitsch
- Institute of Medical Microbiology and Hygiene Division for Public Health, Austrian Agency for Health and Food Safety, Vienna, Austria
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6
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Integrative Assessment of Reduced Listeria monocytogenes Susceptibility to Benzalkonium Chloride in Produce Processing Environments. Appl Environ Microbiol 2022; 88:e0126922. [PMID: 36226965 PMCID: PMC9642021 DOI: 10.1128/aem.01269-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
For decades, quaternary ammonium compounds (QAC)-based sanitizers have been broadly used in food processing environments to control foodborne pathogens such as Listeria monocytogenes. Still, there is a lack of consensus on the likelihood and implication of reduced Listeria susceptibility to benzalkonium chloride (BC) that may emerge due to sublethal exposure to the sanitizers in food processing environments. With a focus on fresh produce processing, we attempted to fill multiple data and evidence gaps surrounding the debate. We determined a strong correlation between tolerance phenotypes and known genetic determinants of BC tolerance with an extensive set of fresh produce isolates. We assessed BC selection on L. monocytogenes through a large-scale and source-structured genomic survey of 25,083 publicly available L. monocytogenes genomes from diverse sources in the United States. With the consideration of processing environment constraints, we monitored the temporal onset and duration of adaptive BC tolerance in both tolerant and sensitive isolates. Finally, we examined residual BC concentrations throughout a fresh produce processing facility at different time points during daily operation. While genomic evidence supports elevated BC selection and the recommendation for sanitizer rotation in the general context of food processing environments, it also suggests a marked variation in the occurrence and potential impact of the selection among different commodities and sectors. For the processing of fresh fruits and vegetables, we conclude that properly sanitized and cleaned facilities are less affected by BC selection and unlikely to provide conditions that are conducive for the emergence of adaptive BC tolerance in L. monocytogenes. IMPORTANCE Our study demonstrates an integrative approach to improve food safety assessment and control strategies in food processing environments through the collective leveraging of genomic surveys, laboratory assays, and processing facility sampling. In the example of assessing reduced Listeria susceptibility to a widely used sanitizer, this approach yielded multifaceted evidence that incorporates population genetic signals, experimental findings, and real-world constraints to help address a lasting debate of policy and practical importance.
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7
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Rodríguez-López P, Rodríguez-Herrera JJ, López Cabo M. Architectural Features and Resistance to Food-Grade Disinfectants in Listeria monocytogenes- Pseudomonas spp. Dual-Species Biofilms. Front Microbiol 2022; 13:917964. [PMID: 35756028 PMCID: PMC9218357 DOI: 10.3389/fmicb.2022.917964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 05/04/2022] [Indexed: 11/13/2022] Open
Abstract
Listeria monocytogenes is considered a foodborne pathogen of serious concern capable of forming multispecies biofilms with other bacterial species, such as Pseudomonas spp., adhered onto stainless steel (SS) surfaces. In an attempt to link the biofilms' morphology and resistance to biocides, dual-species biofilms of L. monocytogenes, in co-culture with either Pseudomonas aeruginosa, Pseudomonas fluorescens, or Pseudomonas putida, were assayed to ascertain their morphological characteristics and resistance toward benzalkonium chloride (BAC) and neutral electrolyzed water (NEW). Epifluorescence microscopy analysis revealed that each dual-species biofilm was distributed differently over the SS surface and that these differences were attributable to the presence of Pseudomonas spp. Confocal laser scanning microscopy (CLSM) assays demonstrated that despite these differences in distribution, all biofilms had similar maximum thicknesses. Along with this, colocalization analyses showed a strong trend of L. monocytogenes to share location within the biofilm with all Pseudomonas assayed whilst the latter distributed throughout the surface independently of the presence of L. monocytogenes, a fact that was especially evident in those biofilms in which cell clusters were present. Finally, a modified Gompertz equation was used to fit biofilms' BAC and NEW dose-response data. Outcomes demonstrated that L. monocytogenes was less susceptible to BAC when co-cultured with P. aeruginosa or P. fluorescens, whereas susceptibility to NEW was reduced in all three dual-species biofilms, which can be attributable to both the mechanism of action of the biocide and the architectural features of each biofilm. Therefore, the results herein provided can be used to optimize already existing and develop novel target-specific sanitation treatments based on the mechanism of action of the biocide and the biofilms' species composition and structure.
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Affiliation(s)
- Pedro Rodríguez-López
- Laboratory of Microbiology and Technology of Marine Products (MICROTEC), Instituto de Investigacións Mariñas (IIM-CSIC), Vigo, Spain
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8
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Nonsynonymous Mutations in fepR Are Associated with Adaptation of Listeria monocytogenes and Other Listeria spp. to Low Concentrations of Benzalkonium Chloride but Do Not Increase Survival of L. monocytogenes and Other Listeria spp. after Exposure to Benzalkonium Chloride Concentrations Recommended for Use in Food Processing Environments. Appl Environ Microbiol 2022; 88:e0048622. [PMID: 35587542 PMCID: PMC9195947 DOI: 10.1128/aem.00486-22] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Selection for Listeria monocytogenes strains that are tolerant to quaternary ammonium compounds (such as benzalkonium chloride [BC]) is a concern across the food industry, including in fresh produce processing environments. This study evaluated the ability of 67 strains of produce-associated L. monocytogenes and other Listeria spp. (“parent strains”) to show enhanced BC tolerance after serial passaging in increasing BC concentrations and to maintain this tolerance after substreaking in the absence of BC. After serial passaging in BC, 62/67 “BC passaged cultures” showed higher MICs (4 to 20 mg/L) than parent strains (2 to 6 mg/L). After the substreaking of two isolates from BC passaged cultures for each parent strain, 105/134 “adapted isolates” maintained MICs (4 to 6 mg/L) higher than parent strain MICs. These results suggested that adapted isolates acquired heritable adaptations that confer BC tolerance. Whole-genome sequencing and Sanger sequencing of fepR, a local repressor of the MATE family efflux pump FepA, identified nonsynonymous fepR mutations in 48/67 adapted isolates. The mean inactivation of adapted isolates after exposure to use-level concentrations of BC (300 mg/L) was 4.48 log, which was not significantly different from inactivation observed in parent strains. Serial passaging of cocultures of L. monocytogenes strains containing bcrABC or qacH did not yield adapted isolates that showed enhanced BC tolerance in comparison to that of monocultures. These results suggest that horizontal gene transfer either did not occur or did not yield isolates with enhanced BC tolerance. Overall, this study provides new insights into selection of BC tolerance among L. monocytogenes and other Listeria spp. IMPORTANCEListeria monocytogenes tolerance to quaternary ammonium compounds has been raised as a concern with regard to L. monocytogenes persistence in food processing environments, including in fresh produce packing and processing environments. Persistence of L. monocytogenes can increase the risk of product contamination, food recalls, and foodborne illness outbreaks. Our study shows that strains of L. monocytogenes and other Listeria spp. can acquire heritable adaptations that confer enhanced tolerance to low concentrations of benzalkonium chloride, but these adaptations do not increase survival of L. monocytogenes and other Listeria spp. when exposed to concentrations of benzalkonium chloride used for food contact surface sanitation (300 mg/L). Overall, these findings suggest that the emergence of benzalkonium chloride-tolerant Listeria strains in food processing environments is of limited concern, as even strains adapted to gain higher MICs in vitro maintain full sensitivity to the concentrations of benzalkonium chloride used for food contact surface sanitation.
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9
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Jiang X, Jiang C, Yu T, Jiang X, Ren S, Kang R, Qiu S. Benzalkonium Chloride Adaptation Increases Expression of the Agr System, Biofilm Formation, and Virulence in Listeria monocytogenes. Front Microbiol 2022; 13:856274. [PMID: 35283841 PMCID: PMC8905296 DOI: 10.3389/fmicb.2022.856274] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 02/01/2022] [Indexed: 11/13/2022] Open
Abstract
Benzalkonium chloride (BC) is widely used for disinfection in food industry. However, prolonged exposure to BC may lead to the emergence of BC adapted strains of Listeria monocytogenes, an important foodborne pathogen. Until now, two communication systems, the LuxS/AI-2 system and the Agr system, have been identified in L. monocytogenes. This study aimed to investigate the role of communication systems in BC adaptation and the effect of BC adaptation on two communication systems and the communication-controlled behaviors in L. monocytogenes. Results demonstrated that the Agr system rather than the LuxS system plays an important role in BC adaptation of L. monocytogenes. Neither luxS expression nor AI-2 production was affected by BC adaptation. On the other hand, the expression of the agr operon and the activity of the agr promoter were significantly increased after BC adaptation. BC adaptation enhanced biofilm formation of L. monocytogenes. However, swarming motility was reduced by BC adaptation. Data from qRT-PCR showed that flagella-mediated motility-related genes (flaA, motA, and motB) were downregulated in BC adapted strains. BC adaptation increased the ability of L. monocytogenes to adhere to and invade Caco-2 cells but did not affect the hemolytic activity. Compared with the wild-type strains, the expression levels of virulence genes prfA, plcA, mpl, actA, and plcB increased more than 2-fold in BC adapted strains; however, lower than 2-fold changes in the expression of hemolysis-associated gene hly were observed. Our study suggests that BC adaptation could increase the expression of the Agr system and enhance biofilm formation, invasion, and virulence of L. monocytogenes, which brings about threats to food safety and public health. Therefore, effective measures should be taken to avoid the emergence of BC adapted strains of L. monocytogenes.
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Affiliation(s)
- Xiaobing Jiang
- Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Congyi Jiang
- Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Tao Yu
- School of Life Sciences & Basic Medicine, Xinxiang University, Xinxiang, China.,Key Laboratory of Biomedicine and Health Risk Warning of Xinxiang City, Xinxiang, China
| | - Xiaojie Jiang
- School of Life Sciences & Basic Medicine, Xinxiang University, Xinxiang, China
| | - Siyu Ren
- Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Rui Kang
- Henan Engineering Laboratory for Bioconversion Technology of Functional Microbes, College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Shuxing Qiu
- Key Laboratory of Biomedicine and Health Risk Warning of Xinxiang City, Xinxiang, China
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10
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Bland R, Brown SRB, Waite-Cusic J, Kovacevic J. Probing antimicrobial resistance and sanitizer tolerance themes and their implications for the food industry through the Listeria monocytogenes lens. Compr Rev Food Sci Food Saf 2022; 21:1777-1802. [PMID: 35212132 DOI: 10.1111/1541-4337.12910] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 12/18/2021] [Accepted: 12/23/2021] [Indexed: 12/12/2022]
Abstract
The development of antibiotic resistance is a serious public health crisis, reducing our ability to effectively combat infectious bacterial diseases. The parallel study of reduced susceptibility to sanitizers is growing, particularly for environmental foodborne pathogens, such as Listeria monocytogenes. As regulations demand a seek-and-destroy approach for L. monocytogenes, understanding sanitizer efficacy and its uses are critical for the food industry. Studies have reported the ability of L. monocytogenes to survive in sanitizer concentrations 10-1000 times lower than the manufacturer-recommended concentration (MRC). Notably, data show that at MRC and when applied according to the label instructions, sanitizers remain largely effective. Studies also report that variables such as the presence of organic material, application time/temperature, and bacterial attachment to surfaces can impact sanitizer effectiveness. Due to the lack of standardization in the methodology and definitions of sanitizer resistance, tolerance, and susceptibility, different messages are conveyed in different studies. In this review, we examine the diversity of definitions, terminology, and methodologies used in studies examining L. monocytogenes resistance and susceptibility to antimicrobials. Research available to date fails to demonstrate "resistance" of L. monocytogenes to recommended sanitizer treatments as prescribed by the label. As such, sanitizer tolerance would be a more accurate description of L. monocytogenes response to low sanitizer concentrations (i.e., sub-MRC). Conservative use of word "resistance" will reduce confusion and allow for concise messaging as sanitizer research findings are communicated to industry and regulators.
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Affiliation(s)
- Rebecca Bland
- Food Innovation Center, Oregon State University, Portland, Oregon, USA.,Department of Food Science and Technology, Oregon State University, Corvallis, Oregon, USA
| | - Stephanie R B Brown
- Food Innovation Center, Oregon State University, Portland, Oregon, USA.,Department of Food Science and Technology, Oregon State University, Corvallis, Oregon, USA
| | - Joy Waite-Cusic
- Department of Food Science and Technology, Oregon State University, Corvallis, Oregon, USA
| | - Jovana Kovacevic
- Food Innovation Center, Oregon State University, Portland, Oregon, USA.,Department of Food Science and Technology, Oregon State University, Corvallis, Oregon, USA
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11
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Bland R, Waite-Cusic J, Weisberg AJ, Riutta ER, Chang JH, Kovacevic J. Adaptation to a Commercial Quaternary Ammonium Compound Sanitizer Leads to Cross-Resistance to Select Antibiotics in Listeria monocytogenes Isolated From Fresh Produce Environments. Front Microbiol 2022; 12:782920. [PMID: 35082767 PMCID: PMC8784610 DOI: 10.3389/fmicb.2021.782920] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 12/06/2021] [Indexed: 12/12/2022] Open
Abstract
The effective elimination of Listeria monocytogenes through cleaning and sanitation is of great importance to the food processing industry. Specifically in fresh produce operations, the lack of a kill step requires effective cleaning and sanitation to mitigate the risk of cross-contamination from the environment. As facilities rely on sanitizers to control L. monocytogenes, reports of the development of tolerance to sanitizers and other antimicrobials through cross-resistance is of particular concern. We investigated the potential for six L. monocytogenes isolates from fresh produce handling and processing facilities and packinghouses to develop cross-resistance between a commercial sanitizer and antibiotics. Experimental adaptation of isolates belonging to hypervirulent clonal complexes (CC2, CC4, and CC6) to a commercial quaternary ammonium compound sanitizer (cQAC) resulted in elevated minimum inhibitory concentrations (2–3 ppm) and minimum bactericidal concentrations (3–4 ppm). Susceptibility to cQAC was restored for all adapted (qAD) isolates in the presence of reserpine, a known efflux pump inhibitor. Reduced sensitivity to 7/17 tested antibiotics (chloramphenicol, ciprofloxacin, clindamycin, kanamycin, novobiocin, penicillin, and streptomycin) was observed in all tested isolates. qAD isolates remained susceptible to antibiotics commonly used in the treatment of listeriosis (i.e., ampicillin and gentamicin). The whole genome sequencing of qAD strains, followed by comparative genomic analysis, revealed several mutations in fepR, the regulator for FepA fluoroquinolone efflux pump. The results suggest that mutations in fepR play a role in the reduction in antibiotic susceptibility following low level adaptation to cQAC. Further investigation into the cross-resistance mechanisms and pressures leading to the development of this phenomenon among L. monocytogenes isolates recovered from different sources is needed to better understand the likelihood of cross-resistance development in food chain isolates and the implications for the food industry.
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Affiliation(s)
- Rebecca Bland
- Food Innovation Center, Oregon State University, Portland, OR, United States.,Department of Food Science and Technology, Oregon State University, Corvallis, OR, United States
| | - Joy Waite-Cusic
- Department of Food Science and Technology, Oregon State University, Corvallis, OR, United States
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Elizabeth R Riutta
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, United States
| | - Jovana Kovacevic
- Food Innovation Center, Oregon State University, Portland, OR, United States.,Department of Food Science and Technology, Oregon State University, Corvallis, OR, United States
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12
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Lakicevic BZ, Den Besten HMW, De Biase D. Landscape of Stress Response and Virulence Genes Among Listeria monocytogenes Strains. Front Microbiol 2022; 12:738470. [PMID: 35126322 PMCID: PMC8811131 DOI: 10.3389/fmicb.2021.738470] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 11/30/2021] [Indexed: 12/23/2022] Open
Abstract
The pathogenic microorganism Listeria monocytogenes is ubiquitous and responsible for listeriosis, a disease with a high mortality rate in susceptible people. It can persist in different habitats, including the farm environment, the food production environments, and in foods. This pathogen can grow under challenging conditions, such as low pH, low temperatures, and high salt concentrations. However, L. monocytogenes has a high degree of strain divergence regarding virulence potential, environmental adaption, and stress response. This review seeks to provide the reader with an up-to-date overview of clonal and serotype-specific differences among L. monocytogenes strains. Emphasis on the genes and genomic islands responsible for virulence and resistance to environmental stresses is given to explain the complex adaptation among L. monocytogenes strains. Moreover, we highlight the use of advanced diagnostic technologies, such as whole-genome sequencing, to fine-tune quantitative microbiological risk assessment for better control of listeriosis.
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Affiliation(s)
- Brankica Z. Lakicevic
- Institute of Meat Hygiene and Technology, Belgrade, Serbia
- *Correspondence: Brankica Z. Lakicevic,
| | | | - Daniela De Biase
- Department of Medico-Surgical Sciences and Biotechnologies, Sapienza University of Rome, Latina, Italy
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13
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Unrath N, McCabe E, Macori G, Fanning S. Application of Whole Genome Sequencing to Aid in Deciphering the Persistence Potential of Listeria monocytogenes in Food Production Environments. Microorganisms 2021; 9:1856. [PMID: 34576750 PMCID: PMC8464834 DOI: 10.3390/microorganisms9091856] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 01/26/2023] Open
Abstract
Listeria monocytogenes is the etiological agent of listeriosis, a foodborne illness associated with high hospitalizations and mortality rates. This bacterium can persist in food associated environments for years with isolates being increasingly linked to outbreaks. This review presents a discussion of genomes of Listeria monocytogenes which are commonly regarded as persisters within food production environments, as well as genes which are involved in mechanisms aiding this phenotype. Although criteria for the detection of persistence remain undefined, the advent of whole genome sequencing (WGS) and the development of bioinformatic tools have revolutionized the ability to find closely related strains. These advancements will facilitate the identification of mechanisms responsible for persistence among indistinguishable genomes. In turn, this will lead to improved assessments of the importance of biofilm formation, adaptation to stressful conditions and tolerance to sterilizers in relation to the persistence of this bacterium, all of which have been previously associated with this phenotype. Despite much research being published around the topic of persistence, more insights are required to further elucidate the nature of true persistence and its implications for public health.
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Affiliation(s)
- Natalia Unrath
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
| | - Evonne McCabe
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
- Department of Microbiology, St. Vincent’s University Hospital, D04 T6F4 Dublin, Ireland
| | - Guerrino Macori
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
| | - Séamus Fanning
- UCD-Centre for Food Safety, School of Public Health, Physiotherapy & Sports Science, University College Dublin, D04 N2E5 Dublin, Ireland; (N.U.); (E.M.); (G.M.)
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14
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El-Zamkan MA, Hendy BA, Diab HM, Marraiki N, Batiha GES, Saber H, Younis W, Thangamani S, Alzahrani KJ, Ahmed AS. Control of Virulent Listeria monocytogenes Originating from Dairy Products and Cattle Environment Using Marine Algal Extracts, Silver Nanoparticles Thereof, and Quaternary Disinfectants. Infect Drug Resist 2021; 14:2721-2739. [PMID: 34290510 PMCID: PMC8289371 DOI: 10.2147/idr.s300593] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 04/30/2021] [Indexed: 11/23/2022] Open
Abstract
Introduction Listeria monocytogenes is an important foodborne pathogen of public- and animal-health concern globally. The persistence of L. monocytogenes in the dairy-processing environment has multifactorial causes, including lack of hygiene, inefficient cleaning, and improper disinfection practices. Materials and Methods A total of 300 dairy-product and environmental samples were collected from dairy-cattle facilities and local dairy shops and vendors in Qena, Egypt. Samples were screened for the incidence of Listeria spp. and to detect virulence determinants and disinfectant-resistance genes. Three marine algal species - Caulerpa racemosa, Jania rubens, and Padina pavonica - were collected from Hurghada on the Red Sea coast. Algal extracts were screened using gas chromatography-mass spectrometry. The antimicrobial activity of some marine algal extracts, nanoparticles derived therefrom, and some disinfectants against L. monocytogenes strains were assessed in vitro using agar-well diffusion and liquid-broth methods. The impact of P. pavonica extract on the growth and survival of virulent L. monocytogenes in cheese and whey were clarified. Results and Discussion The incidence of L. monocytogenes in dairy products and environmental samples was 15.5% and 19%, respectively. The most common toxigenic gene profile found among the isolates was hlyA +-inlA +-prfA +. The sensitivity pattern of L. monocytogenes strains to disinfectant containing alkyl (C12-16) dimethyl BAC was high compared to other tested quaternary ammonium compounds (QAC) disinfectants tested, which showed lower log reductions against resistant strains. The QAC disinfectant-resistance gene qacH was detected in 40% of the isolates. Potent bactericidal activity of a petroleum ether extract of P. pavonica and silver nanoparticles of P. pavonica were obtained against the virulent L. monocytogenes strain. The population of L. monocytogenes in cheese curd and whey after 14 days was reduced at a rate of 9 log CFU/g and 8 log CFU/mL, respectively due to the effect of P. pavonica extract. After 28 days of storage, L. monocytogenes was completely inactivated in those dairy products. Conclusion P. pavonica extract showed promising antimicrobial properties, calling for further comprehensive studies prior to it being applied in the food industry to enhance the safety, quality, and shelf life of products and protect public health.
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Affiliation(s)
- Mona A El-Zamkan
- Department of Food Hygiene and Control (Milk Hygiene), Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt
| | - Bassma A Hendy
- Reference Lab for Food Safety, Animal Health Research Institute (AHRI), Agriculture Research Center (ARC), Dokki, Giza, 12622, Egypt
| | - Hassan Mahmoud Diab
- Department of Animal and Poultry Health and Environment, Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt
| | - Najat Marraiki
- Department of Botany and Microbiology, College of Science, King Saud University, Riyadh, 11451, Saudi Arabia
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, Al-Beheira 22511, Egypt
| | - Hani Saber
- Department of Botany and Microbiology, Faculty of Science, South Valley University, Qena, 83523, Egypt
| | - Waleed Younis
- Department of Microbiology, Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt
| | - Shankar Thangamani
- Department of Pathology and Population Medicine, College of Veterinary Medicine, Midwestern University, Glendale, AZ, USA
| | - Khalid J Alzahrani
- Department of Clinical Laboratories Sciences, College of Applied Medical Sciences, Taif University, Taif, 21944, Saudi Arabia
| | - Ahmed Shaban Ahmed
- Department of Food Hygiene and Control (Milk Hygiene), Faculty of Veterinary Medicine, South Valley University, Qena, 83523, Egypt
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15
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Low-Level Tolerance to Fluoroquinolone Antibiotic Ciprofloxacin in QAC-Adapted Subpopulations of Listeria monocytogenes. Microorganisms 2021; 9:microorganisms9051052. [PMID: 34068252 PMCID: PMC8153124 DOI: 10.3390/microorganisms9051052] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Revised: 05/09/2021] [Accepted: 05/10/2021] [Indexed: 12/20/2022] Open
Abstract
There was a development of low-level tolerance to fluoroquinolone antibiotic ciprofloxacin in Listeria monocytogenes after sublethal adaptation to quaternary ammonium compound (QAC). Using eight L. monocytogenes strains, we determined the changes in short-range MIC, growth rate, and survival for heterologous stress response to ciprofloxacin, after sublethal exposure to daily cycles of fixed or gradually increasing concentration of QAC. Three main findings were observed. (1) MIC increase—QAC-adapted subpopulations exhibited a significant increase in short-range MIC of ciprofloxacin, by 1.5 to 2.9 fold, as compared to non-adapted control for 4/8 strains (p < 0.05). (2) Growth rate increase—QAC-adapted subpopulations exhibited significant 2.1- to 6.8- fold increase in growth rate (OD600 at 10 h) in ciprofloxacin-containing broth, as compared to non-adapted control for 5/8 strains (p < 0.05). (3) Survival increase—QAC-adapted subpopulations of L. monocytogenes yielded significantly higher survival in ciprofloxacin-containing agar by 2.2 to 4.3 log CFU/mL for 4/8 strains, as compared to non-adapted control (p ˂ 0.05). However, for other 4/8 strains of L. monocytogenes, there was no increase in survival of QAC-adapted subpopulations, as compared to non-adapted control in ciprofloxacin. These findings suggest the potential formation of low-level ciprofloxacin-tolerant subpopulations in some L. monocytogenes strains when exposed to residual QAC concentrations (where QAC might be used widely) and such cells if not inactivated might create food safety risk.
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16
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Siderakou D, Zilelidou E, Poimenidou S, Tsipra I, Ouranou E, Papadimitriou K, Skandamis P. Assessing the survival and sublethal injury kinetics of Listeria monocytogenes under different food processing-related stresses. Int J Food Microbiol 2021; 346:109159. [PMID: 33773356 DOI: 10.1016/j.ijfoodmicro.2021.109159] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 02/04/2021] [Accepted: 03/06/2021] [Indexed: 12/22/2022]
Abstract
The foodborne pathogen L. monocytogenes can be present in food processing environments where it is exposed to various stressors. These antimicrobial factors, which aim to eliminate the pathogen, can induce sub-lethal injury to the bacterial cells. In the present study, we investigated the efficacy of different treatments (stresses) relevant to food processing and preservation as well as sanitation methods, in generating sub-lethal injury at 4 °C and 20 °C to two L. monocytogenes strains, ScottA and EGDe. Additionally, we evaluated the survival and extent of L. monocytogenes injury after exposure to commonly used disinfectants (peracetic acid and benzalkonium chloride), following habituation in nutrient-deprived, high-salinity medium. Each stress had a different impact on the survival and injury kinetics of L. monocytogenes. The highest injury levels were caused by peracetic acid which, at 4 °C, generated high populations of injured cells without loss of viability. Other injury-inducing stresses were lactic acid and heating. Long-term habituation in nutrient-limited and high salinity medium (4 °C) and subsequent exposure to disinfectants resulted in higher survival and injury in benzalkonium chloride and increased survival, yet with lower injury levels, in peracetic acid at 20 °C. Taken together, these results highlight the potential food safety risk emerging from the occurrence of injured cells by commonly used food processing methods. Consequently, in order to accurately assess the impact of an antimicrobial method, its potential of inducing sublethal injury needs to be considered along with lethality.
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Affiliation(s)
- Danae Siderakou
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece
| | - Evangelia Zilelidou
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece
| | - Sofia Poimenidou
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece
| | - Ioanna Tsipra
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece
| | - Eleni Ouranou
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece
| | - Konstantinos Papadimitriou
- Department of Food Science and Technology, University of Peloponnese, Antikalamos, 24100 Kalamata, Greece
| | - Panagiotis Skandamis
- Laboratory of Food Quality Control and Hygiene, Department of Food Science and Human Nutrition, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece.
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17
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Chmielowska C, Korsak D, Szuplewska M, Grzelecka M, Maćkiw E, Stasiak M, Macion A, Skowron K, Bartosik D. Benzalkonium chloride and heavy metal resistance profiles of Listeria monocytogenes strains isolated from fish, fish products and food-producing factories in Poland. Food Microbiol 2021; 98:103756. [PMID: 33875198 DOI: 10.1016/j.fm.2021.103756] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 01/13/2021] [Accepted: 01/29/2021] [Indexed: 01/05/2023]
Abstract
Phenotypic and genotypic resistance to benzalkonium chloride (BC), cadmium and arsenic was tested (by susceptibility assays and molecular methods) in 287 Listeria monocytogenes strains isolated from fish and fish products, and food-producing factories in Poland. Overall, 40% of the isolates were resistant to BC, 56% to cadmium and 41% to arsenic (57% displayed resistance to more than one of the tested compounds). Among BC-resistant isolates, the most commonly detected resistance determinant was the qacH gene (83%). Three distinct types of cadA gene determining resistance to cadmium were detected, with the cadA1 variant predominant (88%), while most arsenic-resistant isolates (86%) harbored the arsA gene associated with a Tn554-like transposon (one strain harbored two copies of arsA in different arsenic resistance cassettes). 53% of all tested isolates contained plasmids (from 4 kb to > 90 kb in size), which were classified into 11 groups (p1-p11) based on their restriction patterns. Interestingly, 12 isolates harbored the small mobilizable pLMST6-like plasmid pLIS3 encoding multidrug efflux pump EmrC. Clustering analysis of PFGE patterns revealed that these isolates represent several diverse bacterial populations, which strongly suggests mobility of the pLMST6-like plasmids among L. monocytogenes strains and their role in dissemination of BC resistance.
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Affiliation(s)
- Cora Chmielowska
- University of Warsaw, Faculty of Biology, Institute of Microbiology, Department of Bacterial Genetics, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Dorota Korsak
- University of Warsaw, Faculty of Biology, Institute of Microbiology, Department of Molecular Microbiology, Miecznikowa 1, 02-096, Warsaw, Poland.
| | - Magdalena Szuplewska
- University of Warsaw, Faculty of Biology, Institute of Microbiology, Department of Bacterial Genetics, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Monika Grzelecka
- University of Warsaw, Faculty of Biology, Institute of Microbiology, Department of Bacterial Genetics, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Elżbieta Maćkiw
- National Institute of Public Health, National Institute of Hygiene, Department of Food Safety, Chocimska 24, 00-791, Warsaw, Poland
| | - Monika Stasiak
- National Institute of Public Health, National Institute of Hygiene, Department of Food Safety, Chocimska 24, 00-791, Warsaw, Poland
| | - Adrian Macion
- University of Warsaw, Faculty of Biology, Institute of Microbiology, Department of Bacterial Genetics, Miecznikowa 1, 02-096, Warsaw, Poland
| | - Krzysztof Skowron
- Nicolaus Copernicus University in Toruń, Collegium Medicum of L. Rydygier, Department of Microbiology, M. Curie Skłodowskiej 9, 85-094, Bydgoszcz, Poland
| | - Dariusz Bartosik
- University of Warsaw, Faculty of Biology, Institute of Microbiology, Department of Bacterial Genetics, Miecznikowa 1, 02-096, Warsaw, Poland
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18
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Duze ST, Marimani M, Patel M. Tolerance of Listeria monocytogenes to biocides used in food processing environments. Food Microbiol 2021; 97:103758. [PMID: 33653529 DOI: 10.1016/j.fm.2021.103758] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 01/19/2021] [Accepted: 01/29/2021] [Indexed: 02/06/2023]
Abstract
Listeria monocytogenes is a foodborne pathogen that causes a life-threatening disease in humans known as listeriosis. Contamination of food during processing is the main route of transmission of Listeria monocytogenes. Therefore, biocides play a crucial role in food processing environments as they act as the first line of defense in the prevention and control of L. monocytogenes. Residues of biocides may be present at sublethal concentrations after disinfection. This, unfortunately, subjects L. monocytogenes to selection pressure, giving rise to tolerant strains, which pose a threat to food safety and public health. This review will give a brief description of L. monocytogenes, the clinical manifestation, treatment of listeriosis as well as recently recorded outbreaks. The article will then discuss the current literature on the ability of L. monocytogenes strains to tolerate biocides especially quaternary ammonium compounds as well as the mechanisms of tolerance towards biocides including the activation of efflux pump systems.
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Affiliation(s)
- Sanelisiwe Thinasonke Duze
- Department of Clinical Microbiology and Infectious Diseases, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193, South Africa.
| | - Musa Marimani
- Department of Anatomical Pathology, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193, South Africa
| | - Mrudula Patel
- Department of Clinical Microbiology and Infectious Diseases, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193, South Africa; National Health Laboratory Services and Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193, South Africa
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19
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20
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Assisi C, Forauer E, Oliver HF, Etter AJ. Genomic and Transcriptomic Analysis of Biofilm Formation in Persistent and Transient Listeria monocytogenes Isolates from the Retail Deli Environment Does Not Yield Insight into Persistence Mechanisms. Foodborne Pathog Dis 2020; 18:179-188. [PMID: 33227214 DOI: 10.1089/fpd.2020.2817] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Persistence of Listeria monocytogenes in retail deli environments is a serious food safety issue, potentially leading to cross-contamination of ready-to-eat foods such as deli meats, salads, and cheeses. We previously discovered strong evidence of L. monocytogenes persistence in delis across multiple states. We hypothesized that this was correlated with isolates' innate characteristics, such as biofilm-forming capacity or gene differences. To test this hypothesis, we sequenced the genomes of 21 L. monocytogenes isolates previously collected longitudinally from the retail deli environment. Isolates were chosen to represent varying attachment capacity and sanitizer tolerance as well as persistence or transience. We used single-nucleotide polymorphism analysis to characterize the isolates' genetic relationships and used BLAST to search the isolates' genomes for antibiotic resistance elements, quaternary ammonium tolerance genes, and stress survival islets. We further chose four isolates for RNA-sequencing analysis and compared their global biofilm transcriptome with their global planktonic transcriptome. We did not find genetic content that explained persistence. The presence of stress survival islet-1 correlated to increased attachment capacity (p < 0.05), but not persistence. Further, the presence of sanitizer tolerance elements was not significantly correlated with phenotypic sanitizer tolerance. Analysis of biofilm versus planktonic gene expression did not show the expected differences in gene expression patterns. Overall, L. monocytogenes persistence in the deli environment is likely a matter of poor sanitation and/or facility design, rather than isolates' biofilm-forming capacity, sanitizer tolerance, or genomic content.
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Affiliation(s)
- Clara Assisi
- Department of Food Science, College of Agriculture, Purdue University, West Lafayette, Indiana, USA.,Purdue Interdisciplinary Life Sciences Program, Purdue University, West Lafayette, Indiana, USA
| | - Emily Forauer
- Department of Nutrition and Food Sciences, College of Agriculture and Life Sciences. The University of Vermont, Burlington, Vermont, USA
| | - Haley F Oliver
- Department of Food Science, College of Agriculture, Purdue University, West Lafayette, Indiana, USA
| | - Andrea J Etter
- Department of Food Science, College of Agriculture, Purdue University, West Lafayette, Indiana, USA.,Purdue Interdisciplinary Life Sciences Program, Purdue University, West Lafayette, Indiana, USA.,Department of Nutrition and Food Sciences, College of Agriculture and Life Sciences. The University of Vermont, Burlington, Vermont, USA
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21
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Characterization of Mobile Genetic Elements Using Long-Read Sequencing for Tracking Listeria monocytogenes from Food Processing Environments. Pathogens 2020; 9:pathogens9100822. [PMID: 33036450 PMCID: PMC7599586 DOI: 10.3390/pathogens9100822] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 09/26/2020] [Accepted: 10/01/2020] [Indexed: 02/02/2023] Open
Abstract
Recently developed nanopore sequencing technologies offer a unique opportunity to rapidly close the genome and to identify complete sequences of mobile genetic elements (MGEs). In this study, 17 isolates of Listeria monocytogenes (Lm) epidemic clone II (ECII) from seven ready-to-eat meat or poultry processing facilities, not known to be associated with outbreaks, were shotgun sequenced, and among them, five isolates were further subjected to long-read sequencing. Additionally, 26 genomes of Lm ECII isolates associated with three listeriosis outbreaks in the U.S. and South Africa were obtained from the National Center for Biotechnology Information (NCBI) database and analyzed to evaluate if MGEs may be used as a high-resolution genetic marker for identifying and sourcing the origin of Lm. The analyses identified four comK prophages in 11 non-outbreak isolates from four facilities and three comK prophages in 20 isolates associated with two outbreaks that occurred in the U.S. In addition, three different plasmids were identified among 10 non-outbreak isolates and 14 outbreak isolates. Each comK prophage and plasmid was conserved among the isolates sharing it. Different prophages from different facilities or outbreaks had significant genetic variations, possibly due to horizontal gene transfer. Phylogenetic analysis showed that isolates from the same facility or the same outbreak always closely clustered. The time of most recent common ancestor of the Lm ECII isolates was estimated to be in March 1816 with the average nucleotide substitution rate of 3.1 × 10−7 substitutions per site per year. This study showed that complete MGE sequences provide a good signal to determine the genetic relatedness of Lm isolates, to identify persistence or repeated contamination that occurred within food processing environment, and to study the evolutionary history among closely related isolates.
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22
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HOLST MEGHANM, BROWN LAURAG, HOOVER EDWARDRICKAMER, JULIAN ERNEST, FAW BRENDAV, HEDEEN NICOLE, MCKELVEY WENDY, NICHOLAS DAVID, RIPLEY DANNY. Retail Deli Characteristics Associated with Sanitizing Solution Concentrations. J Food Prot 2020; 83:1667-1672. [PMID: 32421819 PMCID: PMC8213014 DOI: 10.4315/jfp-20-142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 05/12/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT Listeria monocytogenes is commonly found in retail delicatessen environments. Proper types and concentrations of sanitizers must be used to eliminate this pathogen from surfaces and reduce the consumer's risk for infection. In 2012, the Environmental Health Specialists Network of the Centers for Disease Control and Prevention completed a study on practices in retail delis that can help prevent cross-contamination and growth of L. monocytogenes. The present study focuses on the sanitizing solution used in delis, given its importance to cleaning and reducing pathogen contamination in retail food environments. We identified deli, manager, and worker characteristics associated with use of improper concentrations of sanitizing solution to wipe down food contact surfaces; 22.8% of sanitizing solutions used for wiping food contact surfaces were at improper concentrations. Independent delis were more likely to use improper concentrations of sanitizing solution, as were delis that sold fewer chubs (plastic tubes of meat) per week. Use of improper sanitizing solution concentrations was associated with required food safety training for managers; additional analyses suggest that this relationship is significant for independent but not chain delis. Cleaning and sanitizing must be emphasized in food safety efforts focused on independent and smaller delis. HIGHLIGHTS
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Affiliation(s)
- MEGHAN M. HOLST
- Centers for Disease Control and Prevention, National Center for Environmental Health, 4770 Buford Highway, Atlanta, Georgia 30341;,Author for correspondence. Tel: 404-498-1076; Fax: 770-488-7310;
| | - LAURA G. BROWN
- Centers for Disease Control and Prevention, National Center for Environmental Health, 4770 Buford Highway, Atlanta, Georgia 30341
| | - EDWARD RICKAMER HOOVER
- Centers for Disease Control and Prevention, National Center for Environmental Health, 4770 Buford Highway, Atlanta, Georgia 30341
| | - ERNEST JULIAN
- Rhode Island Department of Health, 3 Capitol Hill, Providence, Rhode Island 02908
| | - BRENDA V. FAW
- California Department of Public Health, P.O. Box 997377, MS 0500, Sacramento, California 95899
| | - NICOLE HEDEEN
- Minnesota Department of Health, 625 Robert Street North, St. Paul, Minnesota 55164
| | - WENDY MCKELVEY
- New York City Department of Health and Mental Hygiene, 125 Worth Street CN-34E, New York, New York 10013
| | - DAVID NICHOLAS
- New York State Department of Health, Empire State Plaza, Albany, New York 12237
| | - DANNY RIPLEY
- Tennessee Department of Health, 710 James Robertson Parkway, Nashville, Tennessee 37243, USA
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23
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Bacteriophage biocontrol to fight Listeria outbreaks in seafood. Food Chem Toxicol 2020; 145:111682. [PMID: 32805341 DOI: 10.1016/j.fct.2020.111682] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 08/04/2020] [Accepted: 08/07/2020] [Indexed: 12/19/2022]
Abstract
Listeria monocytogenes is a well-known pathogen responsible for the severe foodborne disease listeriosis. The control of L. monocytogenes occurrence in seafood products and seafood processing environments is an important challenge for the seafood industry and the public health sector. However, bacteriophage biocontrol shows great potential to be used as safety control measure in seafood. This review provides an update on Listeria-specific bacteriophages, focusing on their application as a safe and natural strategy to prevent L. monocytogenes contamination and growth in seafood products and seafood processing environments. Furthermore, the main properties required from bacteriophages intended to be used as biocontrol tools are summarized and emerging strategies to overcome the current limitations are considered. Also, major aspects relevant for bacteriophage production at industrial scale, their access to the market, as well as the current regulatory status of bacteriophage-based solutions for Listeria biocontrol are discussed.
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Cherifi T, Arsenault J, Pagotto F, Quessy S, Côté JC, Neira K, Fournaise S, Bekal S, Fravalo P. Distribution, diversity and persistence of Listeria monocytogenes in swine slaughterhouses and their association with food and human listeriosis strains. PLoS One 2020; 15:e0236807. [PMID: 32760141 PMCID: PMC7410256 DOI: 10.1371/journal.pone.0236807] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 07/13/2020] [Indexed: 02/05/2023] Open
Abstract
Listeria monocytogenes is the etiological agent of listeriosis, a major foodborne disease and an important public health concern. Contamination of meat with L. monocytogenes occurs frequently at the slaughterhouse. Our aims were; 1) to investigate the distribution of L. monocytogenes in the processing areas of four swine slaughterhouses; 2) to describe the diversity of L. monocytogenes strains by pulsed-field gel electrophoresis; 3) to identify persistent L. monocytogenes strains and describe their distribution; 4) to investigate the associations between persistence of strains and their following characteristics: detection in food isolates, detection in human clinical isolates, and the presence of benzalkonium chloride (BAC) resistance genes. Various operation areas within the four swine slaughterhouses were sampled on four occasions. A total of 2496 samples were analyzed, and L. monocytogenes was successfully isolated from 243 samples. The proportion of positive samples ranged from 32 to 58% in each slaughterhouse and from 24 to 68% in each operation area. Fifty-eight different pulsotypes were identified and eight pulsotypes, present in samples collected during 4 visits, were considered persistent. The persistent pulsotypes were significantly more likely to be detected in food (P < 0.01, exact χ²) and human clinical cases (P < 0.01, exact χ²), respectively. Among pulsotypes harboring the BAC bcrABC resistance cassette or the emrE multidrug transporter gene, 42.8% were persistent compared to 4.5% for pulsotypes without these resistance genes (P < 0.01, exact χ²). Our study highlights the importance of persistent L. monocytogenes strains in the environmental contamination of slaughterhouses, which may lead to repeated contamination of meat products. It also shows that the presence of disinfectants resistance genes is an important contributing factor.
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Affiliation(s)
- Tamazight Cherifi
- Chaire de recherche en salubrité des viandes, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Centre de recherche en infectiologie porcine et avicole (CRIPA-FQRNT), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Groupe de recherche et d’enseignement en salubrité des aliments (GRESA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- * E-mail: (TC); (PF)
| | - Julie Arsenault
- Centre de recherche en infectiologie porcine et avicole (CRIPA-FQRNT), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
| | - Franco Pagotto
- Listeriosis Reference Service, Microbiology Research Division, Bureau of Microbial Hazards, Food Directorate, Health Products and Food Branch, Health Canada, Ottawa, Ontario, Canada
| | - Sylvain Quessy
- Chaire de recherche en salubrité des viandes, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Groupe de recherche et d’enseignement en salubrité des aliments (GRESA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
| | - Jean-Charles Côté
- Chaire de recherche en salubrité des viandes, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Groupe de recherche et d’enseignement en salubrité des aliments (GRESA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
| | - Kersti Neira
- Chaire de recherche en salubrité des viandes, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Centre de recherche en infectiologie porcine et avicole (CRIPA-FQRNT), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Groupe de recherche et d’enseignement en salubrité des aliments (GRESA), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
| | | | - Sadjia Bekal
- Laboratoire de santé publique du Québec, Sainte-Anne-de-Bellevue, Quebec, Canada
| | - Philippe Fravalo
- Chaire de recherche en salubrité des viandes, Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Centre de recherche en infectiologie porcine et avicole (CRIPA-FQRNT), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- Epidemiology of Zoonoses and Public Health Research Unit (GREZOSP), Faculté de médecine vétérinaire, Université de Montréal, Saint-Hyacinthe, Quebec, Canada
- * E-mail: (TC); (PF)
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Alía A, Andrade MJ, Rodríguez A, Martín I, Pérez-Baltar A, Medina M, Córdoba JJ. Prevalence and characterization of Listeria monocytogenes in deboning and slicing areas of Spanish dry-cured ham processing. Lebensm Wiss Technol 2020. [DOI: 10.1016/j.lwt.2020.109498] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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26
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Zhou C, Zhu M, Wang Y, Yang Z, Ye M, Wu L, Bao H, Pang M, Zhou Y, Wang R, Sun L, Wang H, Zheng C, Zhang H. Broad host range phage vB-LmoM-SH3-3 reduces the risk of Listeria contamination in two types of ready-to-eat food. Food Control 2020. [DOI: 10.1016/j.foodcont.2019.106830] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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27
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Noll M, Trunzer K, Vondran A, Vincze S, Dieckmann R, Al Dahouk S, Gold C. Benzalkonium Chloride Induces a VBNC State in Listeria monocytogenes. Microorganisms 2020; 8:microorganisms8020184. [PMID: 32012868 PMCID: PMC7074807 DOI: 10.3390/microorganisms8020184] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Revised: 01/14/2020] [Accepted: 01/23/2020] [Indexed: 02/07/2023] Open
Abstract
The objective of our study was to investigate the effects of benzalkonium chloride (BC) adaptation of L. monocytogenes on the susceptibility to antimicrobial agents and on the viable but non culturable (VBNC) state of the bacterial cells. We adapted L. monocytogenes SLCC2540 to BC by applying BC below minimum inhibitory concentration (MIC) to above minimum bactericidal concentration (MBC). The culturable fractions and the susceptibility of adapted and parental cells to BC were assessed. In addition, cell membrane permeability and glucose uptake were analyzed by multi parametric flow cytometry using the fluorescent agents SYTO9, propidium iodide, and 2-deoxy-2-[(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]-D-glucose (2-NBDG). Adapted cells displayed a two-fold MIC increase of BC and reduced antibiotic susceptibility. At high BC concentrations, the decrease in the number of colony forming units was significantly lower in the population of adapted cells compared to parental cells. At the same time, the number of metabolically active cells with intact membranes was significantly higher than the number of culturable cells. Growth-independent viability assays revealed an adapted subpopulation after BC application that was not culturable, indicating increased abundance of viable but nonculturable (VBNC) cells. Moreover, adapted cells can outcompete non-adapted cells under sublethal concentrations of disinfectants, which may lead to novel public health risks.
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Affiliation(s)
- Matthias Noll
- Institute for Bioanalysis, Department of Applied Sciences, Coburg University of Applied Sciences and Arts, Friedrich-Streib-Straße 2, D-96450 Coburg, Germany; (K.T.); (A.V.); (C.G.)
- Correspondence: ; Tel.: +49-09561-317645
| | - Katharina Trunzer
- Institute for Bioanalysis, Department of Applied Sciences, Coburg University of Applied Sciences and Arts, Friedrich-Streib-Straße 2, D-96450 Coburg, Germany; (K.T.); (A.V.); (C.G.)
| | - Antje Vondran
- Institute for Bioanalysis, Department of Applied Sciences, Coburg University of Applied Sciences and Arts, Friedrich-Streib-Straße 2, D-96450 Coburg, Germany; (K.T.); (A.V.); (C.G.)
| | - Szilvia Vincze
- German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany; (S.V.); (R.D.); (S.A.D.)
| | - Ralf Dieckmann
- German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany; (S.V.); (R.D.); (S.A.D.)
| | - Sascha Al Dahouk
- German Federal Institute for Risk Assessment, Max-Dohrn-Str. 8-10, 10589 Berlin, Germany; (S.V.); (R.D.); (S.A.D.)
| | - Carolin Gold
- Institute for Bioanalysis, Department of Applied Sciences, Coburg University of Applied Sciences and Arts, Friedrich-Streib-Straße 2, D-96450 Coburg, Germany; (K.T.); (A.V.); (C.G.)
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28
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Rodríguez-Campos D, Rodríguez-Melcón C, Alonso-Calleja C, Capita R. Persistent Listeria monocytogenes Isolates from a Poultry-Processing Facility Form more Biofilm but Do Not Have a Greater Resistance to Disinfectants Than Sporadic Strains. Pathogens 2019; 8:E250. [PMID: 31756896 PMCID: PMC6963312 DOI: 10.3390/pathogens8040250] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 10/19/2019] [Accepted: 10/27/2019] [Indexed: 12/26/2022] Open
Abstract
Some strains of Listeria monocytogenes can persist in food-processing environments, increasing the likelihood of the contamination of foodstuffs. To identify traits that contribute to bacterial persistence, a selection of persistent and sporadic L. monocytogenes isolates from a poultry-processing facility was investigated for biofilm-forming ability (crystal violet assay). The susceptibility of sessile cells to treatments (five minutes) with sodium hypochlorite having 10% active chlorine (SHY: 10,000 ppm, 25,000 ppm, and 50,000 ppm) and benzalkonium chloride (BZK: 2500 ppm, 10,000 ppm, and 25,000 ppm) was also studied. All isolates exhibited biofilm formation on polystyrene. Persistent strains showed larger (p < 0.001) biofilm formation (OD580 = 0.301 ± 0.097) than sporadic strains (OD580 = 0.188 ± 0.082). A greater susceptibility to disinfectants was observed for biofilms of persistent strains than for those of sporadic strains. The application of SHY reduced biofilms only for persistent strains. BZK increased OD580 in persistent strains (2500 ppm) and in sporadic strains (all concentrations). These results indicate that the use of BZK at the concentrations tested could represent a public health risk. Findings in this work suggest a link between persistence and biofilm formation, but do not support a relationship between persistence and the resistance of sessile cells to disinfectants.
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Affiliation(s)
- Daniel Rodríguez-Campos
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071 León, Spain; (D.R.-C.); (C.R.-M.); (C.A.-C.)
- Institute of Food Science and Technology, University of León, E-24071 León, Spain
| | - Cristina Rodríguez-Melcón
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071 León, Spain; (D.R.-C.); (C.R.-M.); (C.A.-C.)
- Institute of Food Science and Technology, University of León, E-24071 León, Spain
| | - Carlos Alonso-Calleja
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071 León, Spain; (D.R.-C.); (C.R.-M.); (C.A.-C.)
- Institute of Food Science and Technology, University of León, E-24071 León, Spain
| | - Rosa Capita
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071 León, Spain; (D.R.-C.); (C.R.-M.); (C.A.-C.)
- Institute of Food Science and Technology, University of León, E-24071 León, Spain
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29
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Hauf S, Möller L, Fuchs S, Halbedel S. PadR-type repressors controlling production of a non-canonical FtsW/RodA homologue and other trans-membrane proteins. Sci Rep 2019; 9:10023. [PMID: 31296881 PMCID: PMC6624303 DOI: 10.1038/s41598-019-46347-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 06/27/2019] [Indexed: 01/02/2023] Open
Abstract
The Gram-positive bacterium Listeria monocytogenes occurs ubiquitously in the environment and infects humans upon ingestion. It encodes four PadR-like repressors, out of which LftR has been characterized previously and was shown to control gene expression in response to the antibiotic aurantimycin produced by other environmental bacteria. To better understand the PadR regulons of L. monocytogenes, we performed RNA-sequencing with mutants of the other three repressors LadR, LstR and Lmo0599. We show that LadR is primarily responsible for the regulation of the mdrL gene, encoding an efflux pump, while LstR and Lmo0599 mainly regulate their own operons. The lstR operon contains the lmo0421 gene, encoding a homolog of the RodA/FtsW protein family. However, this protein does not possess such functionality, as we demonstrate here. The lmo0599 operon contains two additional genes coding for the hypothetical trans-membrane proteins lmo0600 and lmo0601. A striking phenotype of the lmo0599 mutant is its impaired growth at refrigeration temperature. In light of these and other results we suggest that Lmo0599 should be renamed and propose LltR (listerial low temperature regulator) as its new designation. Based on the nature of the PadR target genes we assume that these repressors collectively respond to compounds acting on the cellular envelope.
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Affiliation(s)
- Samuel Hauf
- FG11 Division of Enteropathogenic bacteria and Legionella, Robert Koch Institute, Burgstrasse 37, 38855, Wernigerode, Germany
| | - Lars Möller
- ZBS 4 - Advanced Light and Electron Microscopy, Robert Koch Institute, Nordufer 20, 13353, Berlin, Germany
| | - Stephan Fuchs
- FG13 Nosocomial Pathogens and Antibiotic Resistances, Robert Koch Institute, Burgstrasse 37, 38855, Wernigerode, Germany
| | - Sven Halbedel
- FG11 Division of Enteropathogenic bacteria and Legionella, Robert Koch Institute, Burgstrasse 37, 38855, Wernigerode, Germany.
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30
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Kropac AC, Eshwar AK, Stephan R, Tasara T. New Insights on the Role of the pLMST6 Plasmid in Listeria monocytogenes Biocide Tolerance and Virulence. Front Microbiol 2019; 10:1538. [PMID: 31338084 PMCID: PMC6629823 DOI: 10.3389/fmicb.2019.01538] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 06/20/2019] [Indexed: 11/21/2022] Open
Abstract
Listeria monocytogenes the causative agent of listeriosis is an important public health concern and food safety challenge. Increased tolerance of this bacterium to benzalkonium chloride (BC), an antibacterial agent widely used in industrial settings, is a growing issue. Plasmid pLMST6 harboring the gene of the multidrug efflux pump protein EmrC has been recently linked to enhanced BC tolerance and meningitis due to L. monocytogenes ST6 strains. In this study, occurrence and contribution of this plasmid to BC tolerance was examined using PCR, plasmid curing and transformation, RT-qPCR and proteome analysis, respectively. Furthermore, the substrate specificity of the pLMST6 associated EmrC efflux pump and the impact of the plasmid on L. monocytogenes virulence were investigated. pLMST6 was detected in 7 (1.6%) of 439 L. monocytogenes strains isolated from different sources. A phenotypic role of this plasmid in conferring increased BC tolerance was confirmed by showing that plasmid cure increases BC susceptibility whereas plasmid complementation and transformation increased BC tolerance in different L. monocytogenes genetic backgrounds and L. innocua. RT-qPCR showed that BC stress exposure strongly induces the expression of mRNAs associated with pLMST6 genes for EmrC and a TetR transcription regulator. A full proteome analysis in a plasmid harboring L. monocytogenes strain revealed that the pLMST6 encoded putative TetR family transcription regulator protein is the most upregulated protein in response to BC stress exposure. An investigation into the EmrC efflux pump's substrate spectrum showed that while pLMST6 confers increased tolerance to other quaternary ammonium compounds (QACs) based disinfectants it has no impact on the sensitivity of L. monocytogenes to non-QAC disinfectants as well as on antibiotics such as ampicillin, tetracycline and gentamicin. A reduction in the survival of zebrafish embryos infected with pLMST6 plasmid harboring L. monocytogenes strains was observed when compared with plasmid cured variants of the same strains suggesting that some pLMST6 harbored genes might contribute to increased virulence capacity. Overall these results confirm the phenotypic contribution of pLMST6 plasmid in promoting and dissemination of BC tolerance in L. monocytogenes as well as provide new insights on different molecular levels of pLMST6 associated genes in response to BC stress.
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Affiliation(s)
| | | | | | - Taurai Tasara
- Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland
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31
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Benzalkonium Chlorides: Uses, Regulatory Status, and Microbial Resistance. Appl Environ Microbiol 2019; 85:AEM.00377-19. [PMID: 31028024 DOI: 10.1128/aem.00377-19] [Citation(s) in RCA: 167] [Impact Index Per Article: 27.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Benzalkonium chlorides (BACs) are chemicals with widespread applications due to their broad-spectrum antimicrobial properties against bacteria, fungi, and viruses. This review provides an overview of the market for BACs, as well as regulatory measures and available data on safety, toxicity, and environmental contamination. We focus on the effect of frequent exposure of microbial communities to BACs and the potential for cross-resistant phenotypes to emerge. Toward this goal, we review BAC concentrations in consumer products, their correlation with the emergence of tolerance in microbial populations, and the associated risk potential. Our analysis suggests that the ubiquitous and frequent use of BACs in commercial products can generate selective environments that favor microbial phenotypes potentially cross-resistant to a variety of compounds. An analysis of benefits versus risks should be the guidepost for regulatory actions regarding compounds such as BACs.
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32
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Xu D, Deng Y, Fan R, Shi L, Bai J, Yan H. Coresistance to Benzalkonium Chloride Disinfectant and Heavy Metal Ions in Listeria monocytogenes and Listeria innocua Swine Isolates from China. Foodborne Pathog Dis 2019; 16:696-703. [PMID: 31120347 DOI: 10.1089/fpd.2018.2608] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The development of coresistance to disinfectants and heavy metals contributes to the fitness of Listeria spp. in foods or food processing environments, where life-threatening Listeria monocytogenes coexist and coevolve with other Listeria spp. Despite extensive research on L. monocytogenes, coresistance to disinfectants and heavy metals is less documented for other Listeria spp. In this study, we screened 30 L. monocytogenes and 27 Listeria innocua isolates recovered from 273 swine samples for resistance to quaternary ammonium compound benzalkonium chloride (BC) and to heavy metals cadmium (Cd) and arsenic (As). Moreover, we evaluated the potential mechanisms of resistance by detecting the efflux pump activity in BC resistance and the presence of resistance determinants. The average minimum inhibitory concentrations of BC in L. innocua (10.7 ± 2.0) were significantly higher than that in L. monocytogenes (6.9 ± 3.7) (p < 0.05). Resistance to BC and heavy metals was correlated, where all BC-resistant L. innocua and As-resistant L. monocytogenes isolates were coresistant to BC and Cd. Twenty percent and 66.7% of BC resistance in L. monocytogenes and L. innocua were related to reserpine-associated efflux pumps, whereas all cases of BC resistance were related to carbonyl cyanide 3-chlorophenylhydrazone-associated efflux pumps. The cadA1 and cadA2 genes were present in Cd-resistant isolates but not in Cd-sensitive isolates, and cadA3 was undetectable in all isolates examined. cadA4 conferring lower level of Cd resistance was copresent with arsA1 and arsA2 in the Cd-resistant and As-susceptible L. monocytogenes isolate LM3. Our findings suggest that swine serves as a reservoir for developing resistance to disinfectant and heavy metals in L. monocytogenes and L. innocua, which share common resistance mechanisms such as efflux pumps and resistance genes. This work provides new insight into the coresistance events of other Listeria as a potential contributor of the resistance in L. monocytogenes.
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Affiliation(s)
- Dongyang Xu
- School of Food Science and Technology, South China University of Technology, Guangzhou, China
| | - Yan Deng
- State Key Testing Laboratory of Aquatic Products, Guangzhou Airport Entry-Exit Inspection and Quarantine Bureau, Guangzhou, China
| | - Rongdong Fan
- School of Food Science and Technology, South China University of Technology, Guangzhou, China
| | - Lei Shi
- Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China.,State Key Laboratory of Food Safety Technology for Meat Products, Fujian, China
| | - Jianshan Bai
- State Key Testing Laboratory of Aquatic Products, Guangzhou Airport Entry-Exit Inspection and Quarantine Bureau, Guangzhou, China
| | - He Yan
- School of Food Science and Technology, South China University of Technology, Guangzhou, China
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Rodríguez-Melcón C, Riesco-Peláez F, García-Fernández C, Alonso-Calleja C, Capita R. Susceptibility of Listeria monocytogenes planktonic cultures and biofilms to sodium hypochlorite and benzalkonium chloride. Food Microbiol 2019; 82:533-540. [PMID: 31027816 DOI: 10.1016/j.fm.2019.03.020] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 01/07/2019] [Accepted: 03/17/2019] [Indexed: 12/27/2022]
Abstract
The susceptibility of four L. monocytogenes isolates from pork to sodium hypochlorite (SHY) and benzalkonium chloride (BZK) was tested. Minimum inhibitory concentration (MIC) values of 3500 ppm (SHY), or between 3 ppm and 13 ppm (BZK), were found. Minimum bactericidal concentration (MBC) values ranged from 3500 ppm to 4500 ppm (SHY), and from 3 ppm to 14 ppm (BZK). The effect of SHY and BZK on the architecture and cellular viability of 24-h-old biofilms formed by such strains on polystyrene was determined through confocal laser scanning microscopy (CLSM) in conjunction with fluorescent dyes for live cells (SYTO 9) and dead cells (propidium iodide). Strains were able to form biofilm (biovolume values in the observation field of 14,161 μm2 ranged between 103,928.3 ± 6730.2 μm3 and 276,030.9 ± 42,291.9 μm3). Treatment of biofilms for 10 min with SHY (1MIC or 1.5MIC) or BZK (0.5MIC, 1MIC or 1.5MIC) decreased the biovolume of live (potentially dangerous) cells. SHY reduced the cellular viability of biofilms by more than 90%. On the other hand, BZK was able to remove most biofilm mass (live and dead cells), but decreased cellular viability only to a lesser extent, this suggesting strong biofilm detachment and dissemination of live cells.
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Affiliation(s)
- Cristina Rodríguez-Melcón
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071, León, Spain; Institute of Food Science and Technology, University of León, E-24071, León, Spain
| | - Félix Riesco-Peláez
- Department of Electrical Engineering and Systems Engineering and Automatic Control, University of León, E-24071, León, Spain
| | - Camino García-Fernández
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071, León, Spain; Institute of Food Science and Technology, University of León, E-24071, León, Spain
| | - Carlos Alonso-Calleja
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071, León, Spain; Institute of Food Science and Technology, University of León, E-24071, León, Spain
| | - Rosa Capita
- Department of Food Hygiene and Technology, Veterinary Faculty, University of León, E-24071, León, Spain; Institute of Food Science and Technology, University of León, E-24071, León, Spain.
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34
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Kampf G. Antibiotic ResistanceCan Be Enhanced in Gram-Positive Species by Some Biocidal Agents Used for Disinfection. Antibiotics (Basel) 2019; 8:antibiotics8010013. [PMID: 30717270 PMCID: PMC6466599 DOI: 10.3390/antibiotics8010013] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 01/29/2019] [Accepted: 02/01/2019] [Indexed: 12/25/2022] Open
Abstract
Some biocidal agents used for disinfection have been described to enhance antibiotic resistance in Gram-negative species. The aim of this review was therefore to evaluate the effect of 13 biocidal agents at sublethal concentrations on antibiotic resistance in Gram-positive species. A MEDLINE search was performed for each biocidal agent on antibiotic tolerance, antibiotic resistance, horizontal gene transfer, and efflux pump. Most data were reported with food-associated bacterial species. In cells adapted to benzalkonium chloride, a new resistance was most frequently found to ampicillin (seven species), cefotaxime and sulfamethoxazole (six species each), and ceftazidime (five species), some of them with relevance for healthcare-associated infections such as Enterococcus faecium and Enterococcus faecalis. With chlorhexidine, a new resistance was often found to imipenem (ten species) as well as cefotaxime, ceftazidime, and tetracycline (seven species each). Cross-resistance was also found with triclosan and ceftazidime (eight species), whereas it was very uncommon for didecyldimethylammonium chloride or hydrogen peroxide. No cross-resistance to antibiotics has been described after low level exposure to glutaraldehyde, ethanol, propanol, peracetic acid, octenidine, povidone iodine, sodium hypochlorite, and polyhexanide. Preference should be given to disinfectant formulations based on biocidal agents with a low or no selection pressure potential.
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Affiliation(s)
- Günter Kampf
- Institute for Hygiene and Environmental Medicine, University Medicine Greifswald, 17475 Greifswald, Germany.
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35
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Cherifi T, Carrillo C, Lambert D, Miniaï I, Quessy S, Larivière-Gauthier G, Blais B, Fravalo P. Genomic characterization of Listeria monocytogenes isolates reveals that their persistence in a pig slaughterhouse is linked to the presence of benzalkonium chloride resistance genes. BMC Microbiol 2018; 18:220. [PMID: 30572836 PMCID: PMC6302515 DOI: 10.1186/s12866-018-1363-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 12/02/2018] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND The aim of this study was to characterize the genomes of 30 Listeria monocytogenes isolates collected at a pig slaughterhouse to determine the molecular basis for their persistence. RESULTS Comparison of the 30 L. monocytogenes genomes showed that successive isolates (i.e., persistent types) recovered from thew sampling site could be linked on the basis of single nucleotide variants confined to prophage regions. In addition, our study revealed the presence among these strains of the bcrABC cassette which is known to produce efflux pump-mediated benzalkonium chloride resistance, and which may account for the persistence of these isolates in the slaughterhouse environment. The presence of the bcrABC cassette was confirmed by WGS and PCR and the resistance phenotype was determined by measuring minimum inhibitory concentrations. Furthermore, the BC-resistant strains were found to produce lower amounts of biofilm in the presence of sublethal concentrations of BC. CONCLUSIONS High resolution SNP-based typing and determination of the bcrABC cassette may provide a means of distinguishing between resident and sporadic L. monocytogenes isolates, and this in turn will support better management of this pathogen in the food industry.
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Affiliation(s)
- Tamazight Cherifi
- Chaire de Recherche en Salubrité des Viandes, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
- Centre de Recherche sur les Maladies Infectieuses Porcine et Avicole, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
- Groupe de Recherche et D’enseignement En Salubrité Des Aliments, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
| | - Catherine Carrillo
- Food Microbiology Research Team, Canadian Food Inspection Agency, Ottawa, ON Canada
| | - Dominic Lambert
- Food Microbiology Research Team, Canadian Food Inspection Agency, Ottawa, ON Canada
| | - Ilhem Miniaï
- Chaire de Recherche en Salubrité des Viandes, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
- Centre de Recherche sur les Maladies Infectieuses Porcine et Avicole, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
- Groupe de Recherche et D’enseignement En Salubrité Des Aliments, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
| | - Sylvain Quessy
- Chaire de Recherche en Salubrité des Viandes, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
- Centre de Recherche sur les Maladies Infectieuses Porcine et Avicole, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
- Groupe de Recherche et D’enseignement En Salubrité Des Aliments, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
| | - Guillaume Larivière-Gauthier
- Chaire de Recherche en Salubrité des Viandes, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
- Centre de Recherche sur les Maladies Infectieuses Porcine et Avicole, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
- Groupe de Recherche et D’enseignement En Salubrité Des Aliments, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
| | - Burton Blais
- Food Microbiology Research Team, Canadian Food Inspection Agency, Ottawa, ON Canada
| | - Philippe Fravalo
- Chaire de Recherche en Salubrité des Viandes, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
- Centre de Recherche sur les Maladies Infectieuses Porcine et Avicole, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
- Groupe de Recherche et D’enseignement En Salubrité Des Aliments, Faculté de Médecine Vétérinaire, Université de Montréal, Saint-Hyacinthe, QC Canada
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MdrL, a major facilitator superfamily efflux pump of
Listeria monocytogenes
involved in tolerance to benzalkonium chloride. Appl Microbiol Biotechnol 2018; 103:1339-1350. [DOI: 10.1007/s00253-018-9551-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/21/2018] [Accepted: 11/30/2018] [Indexed: 12/16/2022]
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37
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Zhang H, Hu Y, Zhou C, Yang Z, Wu L, Zhu M, Bao H, Zhou Y, Pang M, Wang R, Zhou X. Stress resistance, motility and biofilm formation mediated by a 25kb plasmid pLMSZ08 in Listeria monocytogenes. Food Control 2018. [DOI: 10.1016/j.foodcont.2018.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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38
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Yu T, Jiang X, Zhang Y, Ji S, Gao W, Shi L. Effect of Benzalkonium Chloride Adaptation on Sensitivity to Antimicrobial Agents and Tolerance to Environmental Stresses in Listeria monocytogenes. Front Microbiol 2018; 9:2906. [PMID: 30546352 PMCID: PMC6279922 DOI: 10.3389/fmicb.2018.02906] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 11/13/2018] [Indexed: 01/09/2023] Open
Abstract
Listeria monocytogenes is an important food-borne pathogen that can persist in food processing environments and thus contaminate food products. Benzalkonium chloride (BC) is a common disinfectant widely used in food industry. Selective pressure associated with exposure to BC may result in adaptation to this agent in L. monocytogenes. In this study, the effect of BC adaptation on susceptibility to antimicrobial agents and tolerance to environmental stresses, as well as the role of efflux pumps in BC adaptation were investigated in Listeria monocytogenes. Exposure of L. monocytogenes to progressively increasing concentrations of BC led to adaptation not only to BC but also to several other antimicrobial agents with different modes of action, including cefotaxime, cephalothin, ciprofloxacin, and ethidium bromide (EtBr), indicating that the disinfectant BC has the ability to select for antibiotic resistance. Reserpine, an efflux pump inhibitor, reduced minimum inhibitory concentrations (MICs) of cephalosporins, ciprofloxacin, and EtBr in BC adapted strains, indicating that efflux pumps are involved in cross-adaptation to these antimicrobial agents. Our results showed that expression levels of the efflux pump MdrL in the BC adapted strains increased significantly relative to the corresponding wild-type strains (P < 0.05), with the highest increase in one BC adapted strain named HL06BCA. Moreover, the knockout mutant HL06BCAΔmdrL showed impaired growth compared to that of HL06BCA when exposed to 2 μg/ml of BC. It suggests that efflux pump MdrL is associated with BC adaptation in L. monocytogenes. However, we did not find mdrL to be associated with cross-adaptation to cephalosporins, ciprofloxacin, and EtBr in HL06BCA. Additionally, increased sensitivity to acid, alkali, osmotic, ethanol, and oxidative stresses was observed in most strains after repeated exposure to BC. These results suggest rotation of different disinfectant is helpful to maintain high effectiveness of BC toward L. monocytogenes and ethanol and hydrogen peroxide are at least the appropriate candidates.
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Affiliation(s)
- Tao Yu
- Department of Life Science and Technology, Xinxiang University, Xinxiang, China
| | - Xiaobing Jiang
- Department of Life Sciences, Henan Normal University, Xinxiang, China
| | - Yige Zhang
- Department of Life Sciences, Henan Normal University, Xinxiang, China
| | - Shengdong Ji
- Department of Life Sciences, Henan Normal University, Xinxiang, China
| | - Wujun Gao
- Department of Life Sciences, Henan Normal University, Xinxiang, China
| | - Lei Shi
- Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
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39
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Hung YT, McLandsborough LA, Goddard JM, Bastarrachea LJ. Antimicrobial polymer coatings with efficacy against pathogenic and spoilage microorganisms. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2018.07.046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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40
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Jiang X, Yu T, Xu P, Xu X, Ji S, Gao W, Shi L. Role of Efflux Pumps in the in vitro Development of Ciprofloxacin Resistance in Listeria monocytogenes. Front Microbiol 2018; 9:2350. [PMID: 30319598 PMCID: PMC6170607 DOI: 10.3389/fmicb.2018.02350] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/12/2018] [Indexed: 12/19/2022] Open
Abstract
Efflux is a primary fluoroquinolone resistance mechanism in Listeria monocytogenes. In the present study, ciprofloxacin resistant strains were selected by exposure of sensitive strain to progressively increasing concentrations of ciprofloxacin and then the roles of efflux pumps Lde and MdrL in the development of resistance to ciprofloxacin were also investigated in L. monocytogenes. Ciprofloxacin sensitive strain of L. monocytogenes exhibited reduced susceptibility to this antibiotic after induction. Cross-resistance to ethidium bromide (EtBr) was observed in ciprofloxacin-induced strains. However, cross-resistance to benzalkonium chloride (BC) did not occur in this study. Compared to the wild-type strain HL06, the expression levels of lde were increased in four ciprofloxacin-induced strains. The single-gene deletion mutants of lde and mdrL from the ciprofloxacin-induced resistant strain HL06CIP4 were constructed. However, decreased minimum inhibitory concentration (MIC) of ciprofloxacin was observed only in HL06CIP4Δlde compared to that of the parental strain HL06CIP4. Ciprofloxacin uptake appeared to be obviously increased in HL06CIP4Δlde in relative to HL06CIP4. These evidences suggested that efflux pump Lde is involved in ciprofloxacin resistance in L. monocytogenes HL06CIP4. The deletion of lexA had no effect on the expression levels of lde in HL06CIP4 in the absence or presence of ciprofloxacin, indicating that LexA was not involved in the regulation of efflux pump Lde in L. monocytogenes.
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Affiliation(s)
- Xiaobing Jiang
- College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Tao Yu
- College of Life Science and Technology, Xinxiang University, Xinxiang, China
| | - Ping Xu
- College of Life Science and Technology, Xinxiang University, Xinxiang, China
| | - Xiaobo Xu
- College of Life Science and Technology, Xinxiang University, Xinxiang, China
| | - Shengdong Ji
- College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Wujun Gao
- College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Lei Shi
- Institute of Food Safety and Nutrition, Jinan University, Guangzhou, China
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41
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Luque-Sastre L, Fox EM, Jordan K, Fanning S. A Comparative Study of the Susceptibility of Listeria Species to Sanitizer Treatments When Grown under Planktonic and Biofilm Conditions. J Food Prot 2018; 81:1481-1490. [PMID: 30109972 DOI: 10.4315/0362-028x.jfp-17-466] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Listeria species are ubiquitous in nature and can adapt to survive in a variety of niches, including food processing environments. Listeria species that colonize these environments may also have the potential to persist. Food safety strategies designed to manage these niches include regular cleaning and disinfection with proven sanitizers containing biocide-active compounds. Typically, these sanitizers are effective against bacteria growing under planktonic conditions, but their efficacy may be compromised when bacteria are contained in biofilms. The susceptibility of persistent Listeria isolates, i.e., those capable of forming biofilms, to a selection of sanitizers was investigated. A quaternary ammonium compound-based sanitizer was the biocide most effective against planktonic bacteria, with a MIC of 0.0015 to 0.006%. In contrast, ethanol-based sanitizers were the least effective. Although, no triclosan tolerance was observed for planktonic Listeria isolates, triclosan was the only biocide that resulted in a significant biomass reduction. Differences between Listeria species were observed; L. monocytogenes and L. welshimeri biofilms were more tolerant to quaternary ammonium compound-based sanitizers than were L. innocua biofilms. These findings extend our understanding of the application of commonly used sanitizers in the food industry and the efficacy of these sanitizers against Listeria species and their associated biofilms.
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Affiliation(s)
- Laura Luque-Sastre
- 1 Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Belfield, Dublin D04 N2E5, Ireland (ORCID: http://orcid.org/0000-0002-1922-8836 [S.F.])
| | - Edward M Fox
- 2 CSIRO Agriculture and Food, Werribee, Victoria, Australia; and
| | - Kieran Jordan
- 3 Department of Food Safety, Teagasc Food Research Centre, Moorepark, Fermoy, County Cork, Ireland
| | - Séamus Fanning
- 1 Centre for Food Safety, School of Public Health, Physiotherapy and Sports Science, University College Dublin, Belfield, Dublin D04 N2E5, Ireland (ORCID: http://orcid.org/0000-0002-1922-8836 [S.F.])
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42
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Peña-Gómez N, Ruiz-Rico M, Fernández-Segovia I, Barat JM. Development of amino-functionalized membranes for removal of microorganism. INNOV FOOD SCI EMERG 2018. [DOI: 10.1016/j.ifset.2018.05.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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43
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Rodríguez-López P, Rodríguez-Herrera JJ, Vázquez-Sánchez D, López Cabo M. Current Knowledge on Listeria monocytogenes Biofilms in Food-Related Environments: Incidence, Resistance to Biocides, Ecology and Biocontrol. Foods 2018; 7:E85. [PMID: 29874801 PMCID: PMC6025129 DOI: 10.3390/foods7060085] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 05/31/2018] [Accepted: 06/01/2018] [Indexed: 12/16/2022] Open
Abstract
Although many efforts have been made to control Listeria monocytogenes in the food industry, growing pervasiveness amongst the population over the last decades has made this bacterium considered to be one of the most hazardous foodborne pathogens. Its outstanding biocide tolerance capacity and ability to promiscuously associate with other bacterial species forming multispecies communities have permitted this microorganism to survive and persist within the industrial environment. This review is designed to give the reader an overall picture of the current state-of-the-art in L. monocytogenes sessile communities in terms of food safety and legislation, ecological aspects and biocontrol strategies.
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Affiliation(s)
- Pedro Rodríguez-López
- Department of Microbiology and Technology of Marine Products (MICROTEC), Instituto de Investigaciones Marinas (IIM-CSIC), 6, Eduardo Cabello, 36208 Vigo, Spain.
| | - Juan José Rodríguez-Herrera
- Department of Microbiology and Technology of Marine Products (MICROTEC), Instituto de Investigaciones Marinas (IIM-CSIC), 6, Eduardo Cabello, 36208 Vigo, Spain.
| | - Daniel Vázquez-Sánchez
- "Luiz de Queiroz" College of Agriculture (ESALQ), University of São Paulo (USP), 11, Av. Pádua Dias, 13418-900 São Paulo, Brazil.
| | - Marta López Cabo
- Department of Microbiology and Technology of Marine Products (MICROTEC), Instituto de Investigaciones Marinas (IIM-CSIC), 6, Eduardo Cabello, 36208 Vigo, Spain.
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44
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Heir E, Møretrø T, Simensen A, Langsrud S. Listeria monocytogenes strains show large variations in competitive growth in mixed culture biofilms and suspensions with bacteria from food processing environments. Int J Food Microbiol 2018; 275:46-55. [PMID: 29631210 DOI: 10.1016/j.ijfoodmicro.2018.03.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 03/22/2018] [Accepted: 03/26/2018] [Indexed: 02/05/2023]
Abstract
Interactions and competition between resident bacteria in food processing environments could affect their ability to survive, grow and persist in microhabitats and niches in the food industry. In this study, the competitive ability of L. monocytogenes strains grown together in separate culture mixes with other L. monocytogenes (L. mono mix), L. innocua (Listeria mix), Gram-negative bacteria (Gram- mix) and with a multigenera mix (Listeria + Gram- mix) was investigated in biofilms on stainless steel and in suspensions at 12 °C. The mixed cultures included resident bacteria from processing surfaces in meat and salmon industry represented by L. monocytogenes (n = 6), L. innocua (n = 5) and Gram-negative bacteria (n = 6; Acinetobacter sp., Pseudomonas fragi, Pseudomonas fluorescens, Serratia liquefaciens, Stenotrophomonas maltophilia). Despite hampered in growth in mixed cultures, L. monocytogenes established in biofilms with counts at day nine between 7.3 and 9.0 log per coupon with the lowest counts in the Listeria + G- mix that was dominated by Pseudomonas. Specific L. innocua inhibited growth of L. monocytogenes strains differently; inhibition that was further enhanced by the background Gram-negative microbiota. In these multispecies and multibacteria cultures, the growth competitive effects lead to the dominance of a strong competitor L. monocytogenes strain that was only slightly inhibited by L. innocua and showed strong competitive abilities in mixed cultures with resident Gram-negative bacteria. The results indicates complex patterns of bacterial interactions and L. monocytogenes inhibition in the multibacteria cultures that only partially depend on cell contact and likely involve various antagonistic and bacterial tolerance mechanisms. The study indicates large variations among L. monocytogenes in their competitiveness under multibacterial culture conditions that should be considered in further studies towards understanding of L. monocytogenes persistence in food processing facilities.
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Affiliation(s)
- Even Heir
- Nofima, The Norwegian Institute of Food, Fishery and Aquaculture Research, N-1430 Aas, Norway.
| | - Trond Møretrø
- Nofima, The Norwegian Institute of Food, Fishery and Aquaculture Research, N-1430 Aas, Norway
| | - Andreas Simensen
- Nofima, The Norwegian Institute of Food, Fishery and Aquaculture Research, N-1430 Aas, Norway
| | - Solveig Langsrud
- Nofima, The Norwegian Institute of Food, Fishery and Aquaculture Research, N-1430 Aas, Norway
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45
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Bergholz TM, Shah MK, Burall LS, Rakic-Martinez M, Datta AR. Genomic and phenotypic diversity of Listeria monocytogenes clonal complexes associated with human listeriosis. Appl Microbiol Biotechnol 2018; 102:3475-3485. [PMID: 29500754 DOI: 10.1007/s00253-018-8852-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 02/08/2018] [Accepted: 02/10/2018] [Indexed: 12/11/2022]
Abstract
Listeria monocytogenes is a pathogen of significant concern in many ready to eat foods due to its ability to survive and multiply even under significant environmental stresses. Listeriosis in humans is a concern, especially to high-risk populations such as those who are immunocompromised or pregnant, due to the high rates of morbidity and mortality. Whole genome sequencing has become a routine part of assessing L. monocytogenes isolated from patients, and the frequency of different genetic subtypes associated with listeriosis is now being reported. The recent abundance of genome sequences for L. monocytogenes has provided a wealth of information regarding the variation in core and accessory genomic elements. Newly described accessory genomic regions have been linked to greater virulence capabilities as well as greater resistance to environmental stressors such as sanitizers commonly used in food processing facilities. This review will provide a summary of our current understanding of stress response and virulence phenotypes of L. monocytogenes, within the context of the genetic diversity of the pathogen.
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Affiliation(s)
- Teresa M Bergholz
- Department of Microbiological Sciences, North Dakota State University, 130A Van Es, Fargo, ND, 58102, USA.
| | - Manoj K Shah
- Department of Microbiological Sciences, North Dakota State University, 130A Van Es, Fargo, ND, 58102, USA
| | - Laurel S Burall
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD, 20708, USA
| | - Mira Rakic-Martinez
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD, 20708, USA
| | - Atin R Datta
- Center for Food Safety and Applied Nutrition, Food and Drug Administration, Laurel, MD, 20708, USA
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46
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Mohammed AN, Abdel Aziz SAA. Ecological Study on Listeria monocytogenes and the Extent of its Resistance to Different Disinfectants in Dairy Farm for Improving Animal Health. ACTA ACUST UNITED AC 2017. [DOI: 10.3923/ajava.2017.302.310] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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47
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Piercey MJ, Ells TC, Macintosh AJ, Truelstrup Hansen L. Variations in biofilm formation, desiccation resistance and Benzalkonium chloride susceptibility among Listeria monocytogenes strains isolated in Canada. Int J Food Microbiol 2017; 257:254-261. [PMID: 28710947 DOI: 10.1016/j.ijfoodmicro.2017.06.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 04/18/2017] [Accepted: 06/25/2017] [Indexed: 11/17/2022]
Abstract
Listeria monocytogenes is a pathogenic foodborne microorganism noted for its ability to survive in the environment and food processing facilities. Survival may be related to the phenotype of individual strains including the ability to form biofilms and resist desiccation and/or sanitizer exposure. The objectives of this research were to compare 14 L. monocytogenes strains isolated from blood (3), food (6) and water (5) with respect to their benzalkonium chloride (BAC) sensitivity, desiccation resistance, and ability to form biofilm. Correlations were tested between those responses, and the presence of the SSI-1 (Stress Survival Islet) and LGI1/CC8 (Listeria Genomic Island 1 in a clonal complex 8 background) genetic markers. Genetic sequences from four strains representing different phenotypes were also probed for predicted amino acid differences in biofilm, desiccation, and membrane related genes. The water isolates were among the most desiccation susceptible strains, while strains exhibiting desiccation resistance harboured SSI-1 or both the SSI-1 and LGI1/CC8 markers. BAC resistance was greatest in planktonic LGI1/CC8 cells (relative to non-LGI1/CC8 cells), and higher BAC concentrations were also needed to inhibit the formation of biofilm by LGI1/CC8 strains during incubation for 48h and 6days compared to other strains. Formation of biofilm on stainless steel was not significantly (p>0.05) different among the strains. Analysis of genetic sequence data from desiccation and BAC sensitive (CP4 5-1, CP5 2-3, both from water), intermediate (Lm568, food) and desiccation and BAC resistant (08 5578, blood, human outbreak) strains led to the finding of amino acid differences in predicted functional protein domains in several biofilm, desiccation and peptidoglycan related genes (e.g., lmo0263, lmo0433, lmo0434, lmo0771, lmo0973, lmo1080, lmo1224, lmo1370, lmo1744, and lmo2558). Notably, the LGI1/CC8 strain 08-5578 had a frameshift mutation in lmo1370, a gene previously associated with desiccation resistance. In conclusion, the more desiccation and BAC resistant LGI1/CC8 isolates may pose a challenge for sanitation efforts.
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Affiliation(s)
- Marta J Piercey
- Department of Process Engineering and Applied Science, Dalhousie University, 1360 Barrington Street, Halifax B3H 4R2, Canada.
| | - Timothy C Ells
- Agriculture and Agri-Food Canada, 32 Main Street, Kentville, Nova Scotia, Canada.
| | - Andrew J Macintosh
- Department of Process Engineering and Applied Science, Dalhousie University, 1360 Barrington Street, Halifax B3H 4R2, Canada.
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48
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Rodríguez-López P, Cabo ML. Tolerance development in Listeria monocytogenes-Escherichia coli dual-species biofilms after sublethal exposures to pronase-benzalkonium chloride combined treatments. Food Microbiol 2017. [PMID: 28648294 DOI: 10.1016/j.fm.2017.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
This study was designed to assess the effects that sublethal exposures to pronase (PRN) and benzalkonium chloride (BAC) combined treatments have on Listeria monocytogenes-Escherichia coli dual-species biofilms grown on stainless steel in terms of tolerance development (TD) to these compounds. Additionally, fluorescence microscopy was used to observe the changes of the biofilm structure. PRN-BAC exposure was carried out using three different approaches and TD was evaluated treating biofilms with a final 100 μg/ml PRN followed by 50 μg/ml BAC combined treatment. Results showed that exposure to PRN-BAC significantly decreased the number of adhered L. monocytogenes (P < 0.05), while E. coli counts remained generally unaltered. It was also demonstrated that the incorporation of recovery periods during sublethal exposures increased the tolerance of both species of the mixed biofilm to the final PRN-BAC treatment. Moreover, control biofilms became more resistant to PRN-BAC if longer incubation periods were used. Regardless of the treatment used, log reduction values were generally lower in L. monocytogenes compared to E. coli. Additionally, microscopy images showed an altered morphology produced by sublethal PRN-BAC in exposed L. monocytogenes-E. coli dual-species biofilms compared to control samples. Results also demonstrated that L. monocytogenes-E. coli dual-species biofilms are able to develop tolerance to PRN-BAC combined treatments depending on way they have been previously exposed. Moreover, they suggest that the generation of bacterial tolerance should be included as a parameter for sanitation procedures design.
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Affiliation(s)
- Pedro Rodríguez-López
- Department of Microbiology and Technology of Marine Products, Instituto de Investigaciones Marinas (IIM-CSIC), Eduardo Cabello 6, 36208 Vigo, Pontevedra, Spain
| | - Marta López Cabo
- Department of Microbiology and Technology of Marine Products, Instituto de Investigaciones Marinas (IIM-CSIC), Eduardo Cabello 6, 36208 Vigo, Pontevedra, Spain.
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49
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Odić D, Prah J, Avguštin G. Identification of bacterial contaminants from calcium carbonate filler production lines and an evaluation of biocide based decontamination procedures. BIOFOULING 2017; 33:327-335. [PMID: 28402176 DOI: 10.1080/08927014.2017.1310848] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 03/11/2017] [Indexed: 06/07/2023]
Abstract
The aim of this study was to analyze the bacterial community in the production line of a calcium carbonate filler production company and to investigate possible causes for bacterial presence. Throughout 2012, 24 carbonate slurry and six groundwater samples were analyzed. Pseudomonas and Microbacterium were the most frequent contaminants in the slurry, whereas Pseudomonas and Brevundimonas dominated the groundwater samples. Of the 43 different bacterial strains isolated, only five were found both in the slurry and the groundwater, indicating that the latter was not a major source of contamination. The efficacy of 54 commercial biocidal formulations was tested against an artificial bacterial consortium composed of selected slurry isolates. A formulation containing 7.5-15% (v v-1) bronopol and 1.0-2.5% (v v-1) [chloroisothiazolinone (CIT) + methylisothiazolinone (MIT)] exhibited the highest efficacy. Of the possible causes for bacterial presence, sporogenesis and biocide adsorption to carbonate particles were found to be less probable compared to bacterial adsorption to particles, and the acquisition of resistance to biocides.
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Affiliation(s)
- Duško Odić
- a Microbiology and Microbial Biotechnology, Zootechnical Department, Biotechnical Faculty , University of Ljubljana , Domžale , Slovenia
| | - Jana Prah
- a Microbiology and Microbial Biotechnology, Zootechnical Department, Biotechnical Faculty , University of Ljubljana , Domžale , Slovenia
| | - Gorazd Avguštin
- a Microbiology and Microbial Biotechnology, Zootechnical Department, Biotechnical Faculty , University of Ljubljana , Domžale , Slovenia
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Meier AB, Guldimann C, Markkula A, Pöntinen A, Korkeala H, Tasara T. Comparative Phenotypic and Genotypic Analysis of Swiss and Finnish Listeria monocytogenes Isolates with Respect to Benzalkonium Chloride Resistance. Front Microbiol 2017; 8:397. [PMID: 28386248 PMCID: PMC5362634 DOI: 10.3389/fmicb.2017.00397] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 02/27/2017] [Indexed: 12/29/2022] Open
Abstract
Reduced susceptibility of Listeria monocytogenes to benzalkonium chloride (BC), a quaternary ammonium compound widely used in food processing and hospital environments, is a growing public health and food safety concern. The minimal inhibitory concentration of BC on 392 L. monocytogenes strains from Switzerland (CH) and Finland (FIN) was determined. Within this strain collection, benzalkonium chloride resistance was observed in 12.3% (24/195) of Swiss and 10.6% (21/197) of Finnish strains. In both countries, the highest prevalence of BC-resistant strains (CH: 29.4%; FIN: 38.9%) was detected among serotype 1/2c strains. Based on PCR analysis, genes coding for the qacH efflux pump system were detected for most of the BC-resistant strains (CH: 62.5%; FIN: 52.4%). Some Swiss BC-resistant strains harbored genes coding for the bcrABC (16.7%) efflux pump system, while one Finnish BC-resistant strain harbored the emrE gene previously only described among BC-resistant L. monocytogenes strains from Canada. Interestingly, a subset of BC-resistant strains (CH: 5/24, 20.8%; FIN: 9/21, 42.8%) lacked genes for efflux pumps currently known to confer BC resistance in L. monocytogenes. BC resistance analysis in presence of reserpine showed that the resistance was completely or partially efflux pump dependent in 10 out of the 14 strains lacking the known BC resistance genes. Sequence types 155 and ST403 were over-representated among these strains suggesting that these strains might share similar but yet unknown mechanisms of BC resistance.
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Affiliation(s)
- Anja B Meier
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich Zurich, Switzerland
| | - Claudia Guldimann
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich Zurich, Switzerland
| | - Annukka Markkula
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki Helsinki, Finland
| | - Anna Pöntinen
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki Helsinki, Finland
| | - Hannu Korkeala
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki Helsinki, Finland
| | - Taurai Tasara
- Institute for Food Safety and Hygiene, Vetsuisse Faculty University of Zurich Zurich, Switzerland
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