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Chen Z, Zhang Y, Mao D, Wang X, Luo Y. NaClO Co-selects antibiotic and disinfectant resistance in Klebsiella pneumonia: Implications for the potential risk of extensive disinfectant use during COVID-19 pandemic. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134102. [PMID: 38554506 DOI: 10.1016/j.jhazmat.2024.134102] [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: 10/15/2023] [Revised: 02/01/2024] [Accepted: 03/19/2024] [Indexed: 04/01/2024]
Abstract
The inappropriate use of antibiotics is widely recognized as the primary driver of bacterial antibiotic resistance. However, less attention has been given to the potential induction of multidrug-resistant bacteria through exposure to disinfectants. In this study, Klebsiella pneumonia, an opportunistic pathogen commonly associated with hospital and community-acquired infection, was experimentally exposed to NaClO at both minimum inhibitory concentration (MIC) and sub-MIC levels over a period of 60 days. The result demonstrated that NaClO exposure led to enhanced resistance of K. pneumonia to both NaClO itself and five antibiotics (erythromycin, polymyxin B, gentamicin, tetracycline, and ciprofloxacin). Concurrently, the evolved resistant strains exhibited fitness costs, as evidenced by decreased growth rates. Whole population sequencing revealed that both concentrations of NaClO exposure caused genetic mutations in the genome of K. pneumonia. Some of these mutations were known to be associated with antibiotic resistance, while others had not previously been identified as such. In addition, 11 identified mutations were located in the virulence factors, demonstrating that NaClO exposure may also impact the pathogenicity of K. pneumoniae. Overall, this study highlights the potential for the widespread use of NaClO-containing disinfectants during the COVID-19 pandemic to contribute to the emergence of antibiotic-resistant bacteria. ENVIRONMENTAL IMPLICATION: Considering the potential hazardous effects of disinfectant residues on environment, organisms and biodiversity, the sharp rise in use of disinfectants during COVID-19 pandemic has been considered highly likely to cause worldwide secondary disasters in ecosystems and human health. This study demonstrated that NaClO exposure enhanced the resistance of K. pneumonia to both NaClO and five antibiotics (erythromycin, polymyxin B, gentamicin, tetracycline, and ciprofloxacin), highlighting the widespread use of NaClO-containing disinfectants during the COVID-19 pandemic may increase the emergence of antibiotic-resistant bacteria in the environment.
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Affiliation(s)
- Zeyou Chen
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China
| | - Yulin Zhang
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China
| | - Daqing Mao
- School of Medicine, Nankai University, Tianjin, China
| | - Xiaolong Wang
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China.
| | - Yi Luo
- College of Environmental Science and Engineering, Ministry of Education Key Laboratory of Pollution Processes and Environmental Criteria, Nankai University, Tianjin 300071, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, China.
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2
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Alfei S. Shifting from Ammonium to Phosphonium Salts: A Promising Strategy to Develop Next-Generation Weapons against Biofilms. Pharmaceutics 2024; 16:80. [PMID: 38258091 PMCID: PMC10819902 DOI: 10.3390/pharmaceutics16010080] [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: 11/24/2023] [Revised: 01/03/2024] [Accepted: 01/04/2024] [Indexed: 01/24/2024] Open
Abstract
Since they are difficult and sometimes impossible to treat, infections sustained by multidrug-resistant (MDR) pathogens, emerging especially in nosocomial environments, are an increasing global public health concern, translating into high mortality and healthcare costs. In addition to having acquired intrinsic abilities to resist available antibiotic treatments, MDR bacteria can transmit genetic material encoding for resistance to non-mutated bacteria, thus strongly decreasing the number of available effective antibiotics. Moreover, several pathogens develop resistance by forming biofilms (BFs), a safe and antibiotic-resistant home for microorganisms. BFs are made of well-organized bacterial communities, encased and protected in a self-produced extracellular polymeric matrix, which impedes antibiotics' ability to reach bacteria, thus causing them to lose efficacy. By adhering to living or abiotic surfaces in healthcare settings, especially in intensive care units where immunocompromised older patients with several comorbidities are hospitalized BFs cause the onset of difficult-to-eradicate infections. In this context, recent studies have demonstrated that quaternary ammonium compounds (QACs), acting as membrane disruptors and initially with a low tendency to develop resistance, have demonstrated anti-BF potentialities. However, a paucity of innovation in this space has driven the emergence of QAC resistance. More recently, quaternary phosphonium salts (QPSs), including tri-phenyl alkyl phosphonium derivatives, achievable by easy one-step reactions and well known as intermediates of the Wittig reaction, have shown promising anti-BF effects in vitro. Here, after an overview of pathogen resistance, BFs, and QACs, we have reviewed the QPSs developed and assayed to this end, so far. Finally, the synthetic strategies used to prepare QPSs have also been provided and discussed to spur the synthesis of novel compounds of this class. We think that the extension of the knowledge about these materials by this review could be a successful approach to finding effective weapons for treating chronic infections and device-associated diseases sustained by BF-producing MDR bacteria.
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Affiliation(s)
- Silvana Alfei
- Department of Pharmacy, University of Genoa, Viale Cembrano, 4, 16148 Genova, Italy
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3
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Maillard JY, Pascoe M. Disinfectants and antiseptics: mechanisms of action and resistance. Nat Rev Microbiol 2024; 22:4-17. [PMID: 37648789 DOI: 10.1038/s41579-023-00958-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2023] [Indexed: 09/01/2023]
Abstract
Chemical biocides are used for the prevention and control of infection in health care, targeted home hygiene or controlling microbial contamination for various industrial processes including but not limited to food, water and petroleum. However, their use has substantially increased since the implementation of programmes to control outbreaks of methicillin-resistant Staphylococcus aureus, Clostridioides difficile and severe acute respiratory syndrome coronavirus 2. Biocides interact with multiple targets on the bacterial cells. The number of targets affected and the severity of damage will result in an irreversible bactericidal effect or a reversible bacteriostatic one. Most biocides primarily target the cytoplasmic membrane and enzymes, although the specific bactericidal mechanisms vary among different biocide chemistries. Inappropriate usage or low concentrations of a biocide may act as a stressor while not killing bacterial pathogens, potentially leading to antimicrobial resistance. Biocides can also promote the transfer of antimicrobial resistance genes. In this Review, we explore our current understanding of the mechanisms of action of biocides, the bacterial resistance mechanisms encompassing both intrinsic and acquired resistance and the influence of bacterial biofilms on resistance. We also consider the impact of bacteria that survive biocide exposure in environmental and clinical contexts.
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Affiliation(s)
- Jean-Yves Maillard
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Wales, UK.
| | - Michael Pascoe
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Wales, UK
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Shepherd JA, Parker MD. Repeat-exposure in vitro protocol to assess the risk of antimicrobial resistance (AMR) development from use of personal care products: Case study using an antibacterial liquid handwash. J Microbiol Methods 2023; 215:106851. [PMID: 37907118 DOI: 10.1016/j.mimet.2023.106851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 10/17/2023] [Accepted: 10/27/2023] [Indexed: 11/02/2023]
Abstract
The global crisis we are facing with regard to antibiotic resistance has been largely attributed to the overuse and misuse of antibiotics in healthcare and agriculture. However, there is also growing global concern about cross-resistance between biocides and antibiotics. This has made clear the need for more research in this area along with easy-to-perform, but realistic, methods to characterise the potential risk associated with cross-resistance to antibiotics due to biocide use. The primary aim of this work was to develop a repeat-exposure method for predicting bacterial resistance to microbicides, including their cross-resistance to antibiotics. Realism is incorporated in the presented protocol through the use of relevant concentrations and contact times, validated neutralisers, appropriate test organisms and repeat-exposures. The protocol can be applied to formulated microbicides, as shown in the liquid handwash case study presented here. Five bacterial strains were included in the study: Staphylococcus aureus ATCC 6538, Pseudomonas aeruginosa ATCC 15442, Staphylococcus epidermidis ATCC 14990, Escherichia coli ATCC 10536 and Enterococcus hirae ATCC 10541. The protocol parameters used in the case study reflected a worst-case exposure scenario (in terms of contact time and concentration). The results demonstrated that repeated exposure to the liquid handwash would not be expected to lead to development of bacterial resistance or cross-resistance to antibiotics. It is envisaged that this protocol could be used by manufacturers of microbicidal formulations to assess whether repeated use of the test products would contribute to bacterial resistance development or cross-resistance to antibiotics.
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Affiliation(s)
- J A Shepherd
- Unilever Safety and Environmental Assurance Centre (SEAC), Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK.
| | - M D Parker
- Unilever Safety and Environmental Assurance Centre (SEAC), Colworth Science Park, Sharnbrook, Bedfordshire MK44 1LQ, UK
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Rutala WA, Weber DJ, Barbee SL, Gergen MF, Sobsey MD, Samsa GP, Sickbert-Bennett EE. Evaluation of antibiotic-resistant bacteria in home kitchens and bathrooms: Is there a link between home disinfectant use and antibiotic resistance? Am J Infect Control 2023; 51:A158-A163. [PMID: 37890947 DOI: 10.1016/j.ajic.2023.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Accepted: 04/05/2023] [Indexed: 10/29/2023]
Abstract
OBJECTIVE To determine the relationship between home disinfectant use and the prevalence of antibiotic resistance among environmental isolates of human pathogens. METHODS Bacteria were cultured from 5 kitchen and 5 bathroom sites using quantitative methods. Antibiotic susceptibility was determined by standard methods. Home disinfectant use was assessed via a questionnaire. RESULTS The overall total mean log10 counts (total CFU) for the kitchen and bathroom were 4.31 and 4.88, respectively. Gram-positive bacteria were more common in the bathroom (4.05) than in the kitchen (3.60), while Gram-negative bacilli were more common in the kitchen (4.23) than in the bathroom (3.86). The sink and bath drains were the most contaminated sites with 6.16-log10 of total CFU and 6.6-log10 in the kitchen and bathroom, respectively. Households reported cleaning frequency with a variety of commercial products. Most respondents used antibacterial products (eg, soaps, surface disinfectants) in the home. Antibiotic-resistant pathogens were infrequently isolated in the homes evaluated. CONCLUSIONS Compared to pathogens causing community-acquired clinical infections in the ICARE study, pathogens isolated from households are less likely to demonstrate antibiotic resistance. In addition, no relationship between antibacterial use or frequency of cleaning or disinfection and antibiotic resistance was revealed.
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Affiliation(s)
- William A Rutala
- Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC; NC Statewide Program for Infection Control and Epidemiology, University of North Carolina School of Medicine, Chapel Hill, NC.
| | - David J Weber
- Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC; Department of Infection Prevention, University of North Carolina Health Care System, Chapel Hill, NC
| | - Susan L Barbee
- NC Statewide Program for Infection Control and Epidemiology, University of North Carolina School of Medicine, Chapel Hill, NC
| | - Maria F Gergen
- Department of Infection Prevention, University of North Carolina Health Care System, Chapel Hill, NC
| | - Mark D Sobsey
- Department of Engineering and Environmental Sciences, University of North Carolina School of Public Health, Chapel Hill, NC
| | - Gregory P Samsa
- NC Statewide Program for Infection Control and Epidemiology, University of North Carolina School of Medicine, Chapel Hill, NC
| | - Emily E Sickbert-Bennett
- Division of Infectious Diseases, University of North Carolina School of Medicine, Chapel Hill, NC; Department of Infection Prevention, University of North Carolina Health Care System, Chapel Hill, NC
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Edwards M, Graziadio S, Shore J, Schmitz ND, Galvain T, Danker WA, Kocaman M, Pournaras DJ, Bowley DM, Hardy KJ. Plus Sutures for preventing surgical site infection: a systematic review of clinical outcomes with economic and environmental models. BMC Surg 2023; 23:300. [PMID: 37789307 PMCID: PMC10548560 DOI: 10.1186/s12893-023-02187-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 09/07/2023] [Indexed: 10/05/2023] Open
Abstract
BACKGROUND Surgical site infections (SSIs) represent ~ 20% of all hospital-acquired infections in surgical patients and are associated with prolonged hospital stay, admission to intensive care, and mortality. We conducted a systematic review with economic and environmental models to assess whether triclosan-coated sutures (Plus Sutures) provide benefits over non-coated sutures in the reduction of SSI risk. METHODS Searches were conducted in fifteen databases. A total of 1,991 records were retrieved. Following deduplication and screening by two independent reviewers, 31 randomized controlled trials in adults and children were included in the review. Similarity of the studies was assessed by narrative review and confirmed by quantitative assessment. A fixed effects meta-analysis of SSI incidence model including all groups of patients estimated a risk ratio of 0.71 (95% confidence interval: 0.64 to 0.79) indicating those in the Plus Sutures group had a 29% reduction in the risk of developing an SSI compared with those in the control group (p < 0.001). Safety outcomes were analysed qualitatively. RESULTS The economic model estimated the use of Plus Sutures to result in average cost savings of £13.63 per patient. Plus Sutures remained cost-saving in all subgroup analyses with cost-savings ranging between £11 (clean wounds) and £140 (non-clean wounds). The environmental impact of SSI is substantial, and the model suggests that the introduction of Plus Sutures could result in potential environmental benefits. CONCLUSIONS The evidence suggests that Plus Sutures are associated with a reduced incidence of SSI across all surgery types alongside cost savings when compared with standard sutures.
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Affiliation(s)
- M Edwards
- York Health Economics Consortium, University of York, Enterprise House, Innovation Way, York, YO10 5NQ, UK.
| | - S Graziadio
- York Health Economics Consortium, University of York, Enterprise House, Innovation Way, York, YO10 5NQ, UK
| | - J Shore
- York Health Economics Consortium, University of York, Enterprise House, Innovation Way, York, YO10 5NQ, UK
| | - N D Schmitz
- Johnson & Johnson MEDICAL GmbH, Robert-Koch-Strasse 1, 22851, Norderstedt, Germany
| | - T Galvain
- Global Health Economics, Johnson & Johnson Medical Devices, New Brunswick, NJ, USA
| | - W A Danker
- Ethicon Inc., 1000 US-202, Raritan, NJ, 08869, USA
| | - M Kocaman
- Johnson & Johnson Medical Limited, Berkshire, UK
| | - D J Pournaras
- Department of Bariatric and Metabolic Surgery, Southmead Hospital, North Bristol NHS Trust, Bristol, UK
| | - D M Bowley
- University Hospitals Birmingham NHS Foundation Trust, Mindelsohn Way, Edgbaston, Birmingham, B15 2WB, UK
| | - K J Hardy
- Derbyshire Pathology, University Hospitals Derby and Burton NHS Trust, Royal Derby Hospital, Derby, UK
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Geraldes C, Tavares L, Gil S, Oliveira M. Biocides in the Hospital Environment: Application and Tolerance Development. Microb Drug Resist 2023; 29:456-476. [PMID: 37643289 DOI: 10.1089/mdr.2023.0074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/31/2023] Open
Abstract
Hospital-acquired infections are a rising problem with consequences for patients, hospitals, and health care workers. Biocides can be employed to prevent these infections, contributing to eliminate or reduce microorganisms' concentrations at the hospital environment. These antimicrobials belong to several groups, each with distinct characteristics that need to be taken into account in their selection for specific applications. Moreover, their activity is influenced by many factors, such as compound concentration and the presence of organic matter. This article aims to review some of the chemical biocides available for hospital infection control, as well as the main factors that influence their efficacy and promote susceptibility decreases, with the purpose to contribute for reducing misusage and consequently for preventing the development of resistance to these antimicrobials.
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Affiliation(s)
- Catarina Geraldes
- Department of Animal Health, Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Science (AL4AnimalS), Lisbon, Portugal
| | - Luís Tavares
- Department of Animal Health, Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Science (AL4AnimalS), Lisbon, Portugal
| | - Solange Gil
- Department of Animal Health, Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Science (AL4AnimalS), Lisbon, Portugal
- Department of Animal Health, Biological Isolation and Containment Unit (BICU), Veterinary Hospital, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | - Manuela Oliveira
- Department of Animal Health, Centre for Interdisciplinary Research in Animal Health (CIISA), Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
- Associate Laboratory for Animal and Veterinary Science (AL4AnimalS), Lisbon, Portugal
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8
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Maillard J. Impact of benzalkonium chloride, benzethonium chloride and chloroxylenol on bacterial antimicrobial resistance. J Appl Microbiol 2022; 133:3322-3346. [PMID: 35882500 PMCID: PMC9826383 DOI: 10.1111/jam.15739] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/22/2022] [Accepted: 07/23/2022] [Indexed: 01/11/2023]
Abstract
This review examined 3655 articles on benzalkonium chloride (BKC), benzethonium chloride (BZT) and chloroxylenol (CHO) aiming to understand their impact on antimicrobial resistance. Following the application of inclusion/exclusion criteria, only 230 articles were retained for analysis; 212 concerned BKC, with only 18 for CHO and BZT. Seventy-eight percent of studies used MIC to measure BKC efficacy. Very few studies defined the term 'resistance' and 85% of studies defined 'resistance' as <10-fold increase (40% as low as 2-fold) in MIC. Only a few in vitro studies reported on formulated products and when they did, products performed better. In vitro studies looking at the impact of BKC exposure on bacterial resistance used either a stepwise training protocol or exposure to constant BKC concentrations. In these, BKC exposure resulted in elevated MIC or/and MBC, often associated with efflux, and at time, a change in antibiotic susceptibility profile. The clinical relevance of these findings was, however, neither reported nor addressed. Of note, several studies reported that bacterial strains with an elevated MIC or MBC remained susceptible to the in-use BKC concentration. BKC exposure was shown to reduce bacterial diversity in complex microbial microcosms, although the clinical significance of such a change has not been established. The impact of BKC exposure on the dissemination of resistant genes (notably efflux) remains speculative, although it manifests that clinical, veterinary and food isolates with elevated BKC MIC carried multiple efflux pump genes. The correlation between BKC usage and gene carriage, maintenance and dissemination has also not been established. The lack of clinical interpretation and significance in these studies does not allow to establish with certainty the role of BKC on AMR in practice. The limited literature and BZT and CHO do not allow to conclude that these will impact negatively on emerging bacterial resistance in practice.
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Affiliation(s)
- Jean‐Yves Maillard
- School of Pharmacy and Pharmaceutical SciencesCardiff UniversityCardiffUK
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Do Triclosan Sutures Modify the Microbial Diversity of Surgical Site Infections? A Systematic Review and Meta-Analysis. Microorganisms 2022; 10:microorganisms10050927. [PMID: 35630370 PMCID: PMC9146332 DOI: 10.3390/microorganisms10050927] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 04/25/2022] [Accepted: 04/25/2022] [Indexed: 02/05/2023] Open
Abstract
Randomised controlled clinical trials (RCTs) report a lower incidence rate of surgical site infections (SSIs) with triclosan sutures (TSs) compared with non-triclosan sutures (NTSs). Do triclosan sutures modify the microbial diversity of culture-confirmed SSIs (ccSSIs)? If so, this would support the association between TS antimicrobial activity and the SSI incidence rate. This prospective systematic literature review (PROSPERO CRD42019125099) was conducted according to PRISMA. RCTs that compared the incidence of SSIs with TSs and NTSs and reported microbial counts from SSI cultures per suture group were eligible. The microbial species were grouped by genus, and the association between genera and sutures was tested. The pooled relative risk (RR) of ccSSIs was also calculated. Twelve RCTs were eligible. No publication bias was identified. The microorganism count was 180 in 124 SSIs with TSs versus 246 in 199 SSIs with NTSs. No significant difference in microbial diversity was found, but statistical power was low for test results to support or challenge the association between the antimicrobial activity of TSs and the reduced rate of SSIs. The RR of the ccSSIs was significant and consistent with comprehensive meta-analyses. The certainty of the pooled RR was moderate.
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10
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Chen B, Han J, Dai H, Jia P. Biocide-tolerance and antibiotic-resistance in community environments and risk of direct transfers to humans: Unintended consequences of community-wide surface disinfecting during COVID-19? ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 283:117074. [PMID: 33848900 PMCID: PMC8019131 DOI: 10.1016/j.envpol.2021.117074] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 03/09/2021] [Accepted: 03/30/2021] [Indexed: 05/17/2023]
Abstract
During the current pandemic, chemical disinfectants are ubiquitously and routinely used in community environments, especially on common touch surfaces in public settings, as a means of controlling the virus spread. An underappreciated risk in current regulatory guidelines and scholarly discussions, however, is that the persisting input of chemical disinfectants can exacerbate the growth of biocide-tolerant and antibiotic-resistant bacteria on those surfaces and allow their direct transfers to humans. For COVID-19, the most commonly used disinfecting agents are quaternary ammonium compounds, hydrogen peroxide, sodium hypochlorite, and ethanol, which account for two-thirds of the active ingredients in current EPA-approved disinfectant products for the novel coronavirus. Tolerance to each of these compounds, which can be either intrinsic or acquired, has been observed on various bacterial pathogens. Of those, mutations and horizontal gene transfer, upregulation of efflux pumps, membrane alteration, and biofilm formation are the common mechanisms conferring biocide tolerance in bacteria. Further, the linkage between disinfectant use and antibiotic resistance was suggested in laboratory and real-life settings. Evidence showed that substantial bacterial transfers to hands could effectuate from short contacts with surrounding surfaces and further from fingers to lips. While current literature on disinfectant-induced antimicrobial resistance predominantly focuses on municipal wastes and the natural environments, in reality the community and public settings are most severely impacted by intensive and regular chemical disinfecting during COVID-19 and, due to their proximity to humans, biocide-tolerant and antibiotic-resistant bacteria emerged in these environments may pose risks of direct transfers to humans, particularly in densely populated urban communities. Here we highlight these risk factors by reviewing the most pertinent and up-to-date evidence, and provide several feasible strategies to mitigate these risks in the scenario of a prolonging pandemic.
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Affiliation(s)
- Bo Chen
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, PR China; Department of Environmental Science and Engineering, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, PR China
| | - Jie Han
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, PR China.
| | - Han Dai
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, PR China
| | - Puqi Jia
- Department of Environmental Science and Engineering, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, 730000, PR China
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11
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Evaluation of a Biocide Used in the Biological Isolation and Containment Unit of a Veterinary Teaching Hospital. Antibiotics (Basel) 2021; 10:antibiotics10060639. [PMID: 34071748 PMCID: PMC8229411 DOI: 10.3390/antibiotics10060639] [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: 04/21/2021] [Revised: 05/24/2021] [Accepted: 05/25/2021] [Indexed: 11/17/2022] Open
Abstract
Hospital-acquired infections (HAIs) are a rising problem worldwide, and the best way of coping with them is through infection tracking and surveillance systems, combined with prevention strategies, namely efficient disinfection protocols, that employ various biocides. However, increasing reports about reductions in biocide susceptibility and the development of cross-resistance to antimicrobials emphasize the need for identifying the factors influencing biocide efficiency. In this study, 29 bacterial isolates (n = 3 E. coli, n = 2 Pseudomonas spp., n = 23 Enterococcus spp., and n = 1 Staphylococcus pseudintermedius), obtained from environmental samples collected from the Biological Isolation and Containment Unit (BICU), of the Veterinary Teaching Hospital of the Faculty of Veterinary Medicine, University of Lisbon, were tested in order to determine their antimicrobial susceptibility to various antibiotics. Thirteen of these isolates were further selected in order to determine their antimicrobial susceptibility to Virkon™ S, with and without the presence of organic matter. Afterward, seven of these isolates were incubated in the presence of sub-lethal concentrations of this formulation and, subsequently, new susceptibility profiles were determined. Fourteen of the 29 isolates (48.3%) were classified as multidrug resistant, all previously identified as enterococci. Concerning Virkon™ S's susceptibility, the Minimal Bactericidal Concentration (MBC) of this biocide regarding all isolates was at least eight times lower than the concentration regularly used, when no organic matter was present. However, when organic matter was added, MBC values rose up to 23 times. After exposure to sub-lethal concentrations of Virkon™ S, four enterococci presented a phenotypical change regarding antimicrobial susceptibility towards gentamicin. Virkon™ S also resulted in higher MBC values, up to 1.5 times, in the presence of low concentrations of organic matter, but no rise in these values was observed in assays without interfering substance. Virkon™ S seemed to be an efficient formulation in eliminating all bacteria isolates isolated from the BICU. However, organic matter could represent a hindrance to this ability, which emphasizes the importance of sanitization before disinfection procedures. The changes seen in antimicrobial susceptibility could be explained by a general stress-induced response promoted by the sub-lethal levels of Virkon™ S. Additionally, when no organic matter was present, a decrease in susceptibility to this biocide seemed to be non-existent.
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12
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Maillard JY, Bloomfield SF, Courvalin P, Essack SY, Gandra S, Gerba CP, Rubino JR, Scott EA. Reducing antibiotic prescribing and addressing the global problem of antibiotic resistance by targeted hygiene in the home and everyday life settings: A position paper. Am J Infect Control 2020; 48:1090-1099. [PMID: 32311380 PMCID: PMC7165117 DOI: 10.1016/j.ajic.2020.04.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 04/07/2020] [Accepted: 04/08/2020] [Indexed: 12/12/2022]
Abstract
Antimicrobial resistance (AMR) continues to threaten global health. Although global and national AMR action plans are in place, infection prevention and control is primarily discussed in the context of health care facilities with home and everyday life settings barely addressed. As seen with the recent global SARS-CoV-2 pandemic, everyday hygiene measures can play an important role in containing the threat from infectious microorganisms. This position paper has been developed following a meeting of global experts in London, 2019. It presents evidence that home and community settings are important for infection transmission and also the acquisition and spread of AMR. It also demonstrates that the targeted hygiene approach offers a framework for maximizing protection against colonization and infections, thereby reducing antibiotic prescribing and minimizing selection pressure for the development of antibiotic resistance. If combined with the provision of clean water and sanitation, targeted hygiene can reduce the circulation of resistant bacteria in homes and communities, regardless of a country's Human Development Index (overall social and economic development). Achieving a reduction of AMR strains in health care settings requires a mirrored reduction in the community. The authors call upon national and international policy makers, health agencies, and health care professionals to further recognize the importance of targeted hygiene in the home and everyday life settings for preventing and controlling infection, in a unified quest to tackle AMR.
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Affiliation(s)
- Jean-Yves Maillard
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, UK; International Scientific Forum on Home Hygiene, Somerset, UK.
| | | | | | - Sabiha Y Essack
- Antimicrobial Research Unit, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Sumanth Gandra
- Division of Infectious Diseases, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Charles P Gerba
- Departments of Soil, Water and Environmental Science and Environmental Health, University of Arizona, Tucson, AZ, USA
| | - Joseph R Rubino
- Research & Development, Home Hygiene, Lysol/Harpic, Reckitt Benckiser LLC., One Philips Parkway, Montvale, NJ, USA
| | - Elizabeth A Scott
- College of Natural, Behavioral and Health Sciences, Simmons University, Boston, MA, USA
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Novak Babič M, Gostinčar C, Gunde-Cimerman N. Microorganisms populating the water-related indoor biome. Appl Microbiol Biotechnol 2020; 104:6443-6462. [PMID: 32533304 PMCID: PMC7347518 DOI: 10.1007/s00253-020-10719-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/22/2020] [Accepted: 06/02/2020] [Indexed: 12/17/2022]
Abstract
Modernisation of our households created novel opportunities for microbial growth and thus changed the array of microorganisms we come in contact with. While many studies have investigated microorganisms in the air and dust, tap water, another major input of microbial propagules, has received far less attention. The quality of drinking water in developed world is strictly regulated to prevent immediate danger to human health. However, fungi, algae, protists and bacteria of less immediate concern are usually not screened for. These organisms can thus use water as a vector of transmission into the households, especially if they are resistant to various water treatment procedures. Good tolerance of unfavourable abiotic conditions is also important for survival once microbes enter the household. Limitation of water availability, high or low temperatures, application of antimicrobial chemicals and other measures are taken to prevent indoor microbial overgrowth. These conditions, together with a large number of novel chemicals in our homes, shape the diversity and abundance of indoor microbiota through constant selection of the most resilient species, resulting in a substantial overlap in diversity of indoor and natural extreme environments. At least in fungi, extremotolerance has been linked to human pathogenicity, explaining why many species found in novel indoor habitats (such as dishwasher) are notable opportunistic pathogens. As a result, microorganisms that often enter our households with water and are then enriched in novel indoor habitats might have a hitherto underestimated impact on the well-being of the increasingly indoor-bound human population. KEY POINTS: Domestic environment harbours a large diversity of microorganisms. Microbiota of water-related indoor habitats mainly originates from tap water. Bathrooms, kitchens and household appliances select for polyextremotolerant species. Many household-related microorganisms are human opportunistic pathogens.
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Affiliation(s)
- Monika Novak Babič
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
| | - Cene Gostinčar
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia
- Lars Bolund Institute of Regenerative Medicine, BGI-Qingdao, Qingdao, 266555, China
| | - Nina Gunde-Cimerman
- Department of Biology, Biotechnical Faculty, University of Ljubljana, Jamnikarjeva 101, 1000, Ljubljana, Slovenia.
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14
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Kwaśniewska D, Chen YL, Wieczorek D. Biological Activity of Quaternary Ammonium Salts and Their Derivatives. Pathogens 2020; 9:E459. [PMID: 32531904 PMCID: PMC7350379 DOI: 10.3390/pathogens9060459] [Citation(s) in RCA: 77] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/05/2020] [Accepted: 06/08/2020] [Indexed: 12/20/2022] Open
Abstract
Besides their positive role, microorganisms are related to a number of undesirable effects, including many diseases, biodeterioration and food spoilage, so when their presence is undesired, they must be controlled. Numerous biocides limiting the development of microorganisms have been proposed, however, in this paper the biocidal and inhibitory activity of quaternary ammonium salts (QASs) and their zwitterionic derivatives is addressed. This paper presents the current state of knowledge about the biocidal activity of QAS and their derivatives. Moreover, the known mechanisms of antimicrobial activity and the problem of emerging resistance to QAS are discussed. The latest trends in the study of surfactants and their potential use are also presented.
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Affiliation(s)
- Dobrawa Kwaśniewska
- Department of Technology and Instrumental Analysis, Institute of Quality Science, Poznań University of Economics and Business, 61-875 Poznań, Poland;
| | - Ying-Lien Chen
- Department of Plant Pathology and Microbiology, National Taiwan University, Taipei 100, Taiwan;
| | - Daria Wieczorek
- Department of Technology and Instrumental Analysis, Institute of Quality Science, Poznań University of Economics and Business, 61-875 Poznań, Poland;
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15
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Abstract
Pseudomonas aeruginosa, a versatile Gram-negative pathogen that can cause a wide range of infections, is the most common causative agent in cases of bacterial keratitis associated with contact-lens use. Corneal infections with P. aeruginosa often have poor clinical outcomes and can result in long and costly treatments. During the infection process, the pathogen exploits its large genome, encoding complex regulatory networks and a wide range of virulence factors, including motility and the secretion of various proteases and toxins. Although antibiotic resistance levels in the UK are low, higher levels have been seen in some other countries. In the face of increasing antibiotic resistance, alternative therapeutic approaches such as antivirulence strategies and phage therapy are being developed. There is increasing evidence to suggest that keratitis infections are associated with a phylogenetic subgroup of P. aeruginosa isolates carrying the gene encoding the potent cytotoxin exotoxin U, one of two mutually exclusive exotoxins secreted via the type III secretion system. The mechanisms behind this association are unclear, but understanding the genetic differences that predispose P. aeruginosa to cause corneal infections may allow for the development of targeted and more effective future treatments to reduce the morbidity of P. aeruginosa keratitis. In order to minimize the risk of severe P. aeruginosa eye infections, a wide range of contact-lens disinfection solutions are available. Constant exposure to biocides at a range of concentrations, from sub-inhibitory to inhibitory, could contribute to the development of resistance to both antibiotics and disinfectants.
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Affiliation(s)
- Yasmin Hilliam
- Department of Clinical Infection, Microbiology, and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
| | - Stephen Kaye
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Craig Winstanley
- Department of Clinical Infection, Microbiology, and Immunology, Institute of Infection and Global Health, University of Liverpool, Liverpool, L69 7BE, UK
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Karmakar S, Abraham TJ, Kumar S, Kumar S, Shukla SP, Roy U, Kumar K. Triclosan exposure induces varying extent of reversible antimicrobial resistance in Aeromonas hydrophila and Edwardsiella tarda. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 180:309-316. [PMID: 31102840 DOI: 10.1016/j.ecoenv.2019.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/22/2019] [Accepted: 05/03/2019] [Indexed: 06/09/2023]
Abstract
Triclosan (TCS) is a biocide commonly used in household and personal care items to prevent the microbial growth and is currently considered as an emerging pollutant. It has a ubiquitous distribution which can substantially contribute towards antimicrobial resistance. The present study was designed to evaluate the effect of different concentrations of TCS exposure on the antibiotic sensitivity of aquatic bacteria. Aeromonas hydrophila ATCC® 49140™ and Edwardsiella tarda ATCC® 15947™ exposed to TCS for short (30 min) and long duration (serial passages). The agar-disc diffusion assay during the serial passages of TCS exposure and subsequent exposure withdrawal showed clinically insignificant changes in the zone of inhibition for six selected antibiotics in both bacterial strains at all exposure concentrations. Four folds concentration-dependent increase in the minimum inhibitory concentrations (MICs) of TCS was observed in both the strains following TCS exposure. Similarly, a concentration-dependent increase in the MICs of oxytetracycline (OTC) up to 4 folds in A. hydrophila, and up to 8 folds in E. tarda, was also documented during the TCS exposure. In all the cases, withdrawal of TCS exposure effectively reduced the MICs of TCS and OTC in blank passages suggesting a decline in acquired resistance. The frequencies of mutation during 30 min TCS exposure for E. tarda and A. hydrophila ranged between >10-6 and 10-7 levels. Nevertheless, the TCS exposure did not cause any detectable mutation on the fabV gene of A. hydrophila indicating that the TCS may elicit phenotypic adaptation or other resistance mechanism. Although the reduction in MICs due to exposure withdrawal did not restore the bacterial susceptibility up to the initial level, the study proved that the reduced TCS use could significantly help reduce the antimicrobial-resistance and cross-resistance in pathogenic bacteria.
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Affiliation(s)
- Sutanu Karmakar
- Aquatic Environment and Health Management Division, ICAR- Central Institute of Fisheries Education, Mumbai, 400061, India
| | - T J Abraham
- Department of Aquatic Animal Health, Faculty of Fishery Sciences, West Bengal University of Animal and Fishery Sciences, Kolkata, 700094, India
| | - Saurav Kumar
- Aquatic Environment and Health Management Division, ICAR- Central Institute of Fisheries Education, Mumbai, 400061, India
| | - Sanath Kumar
- Fisheries Resources, Harvest and Post-Harvest Management Division, ICAR- Central Institute of Fisheries Education, Mumbai, 400061, India
| | - S P Shukla
- Aquatic Environment and Health Management Division, ICAR- Central Institute of Fisheries Education, Mumbai, 400061, India
| | - Utsa Roy
- Fish Genetics and Biotechnology Division, ICAR- Central Institute of Fisheries Education, Mumbai, 400061, India
| | - Kundan Kumar
- Aquatic Environment and Health Management Division, ICAR- Central Institute of Fisheries Education, Mumbai, 400061, India.
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17
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Kampf G. Biocidal Agents Used for Disinfection Can Enhance Antibiotic Resistance in Gram-Negative Species. Antibiotics (Basel) 2018; 7:E110. [PMID: 30558235 PMCID: PMC6316403 DOI: 10.3390/antibiotics7040110] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/10/2018] [Accepted: 12/11/2018] [Indexed: 11/17/2022] Open
Abstract
Biocidal agents used for disinfection are usually not suspected to enhance cross-resistance to antibiotics. The aim of this review was therefore to evaluate the effect of 13 biocidal agents at sublethal concentrations on antibiotic resistance in Gram-negative species. A medline search was performed for each biocidal agent on antibiotic tolerance, antibiotic resistance, horizontal gene transfer, and efflux pump. In cells adapted to benzalkonium chloride a new resistance was most frequently found to ampicillin (eight species), cefotaxime (six species), and sulfamethoxazole (three species), some of them with relevance for healthcare-associated infections such as Enterobacter cloacae or Escherichia coli. With chlorhexidine a new resistance was often found to ceftazidime, sulfamethoxazole and imipenem (eight species each) as well as cefotaxime and tetracycline (seven species each). Cross-resistance to antibiotics was also found with triclosan, octenidine, sodium hypochlorite, and didecyldimethylammonium chloride. No cross-resistance to antibiotics has been described after low level exposure to ethanol, propanol, peracetic acid, polyhexanide, povidone iodine, glutaraldehyde, and hydrogen peroxide. Taking into account that some biocidal agents used in disinfectants have no health benefit (e.g., in alcohol-based hand rubs) but may cause antibiotic resistance it is obvious to prefer products without them.
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Affiliation(s)
- Günter Kampf
- University Medicine Greifswald, Institute for Hygiene and Environmental Medicine, 17475 Greifswald, Germany.
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18
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Abstract
Biocides and formulated biocides are used worldwide for an increasing number of applications despite tightening regulations in Europe and in the United States. One concern is that such intense usage of biocides could lead to increased bacterial resistance to a product and cross-resistance to unrelated antimicrobials including chemotherapeutic antibiotics. Evidence to justify such a concern comes mostly from the use of health care-relevant bacterial isolates, although the number of studies of the resistance characteristics of veterinary isolates to biocides have increased the past few years. One problem remains the definition of "resistance" and how to measure resistance to a biocide. This has yet to be addressed globally, although the measurement of resistance is becoming more pressing, with regulators both in Europe and in the United States demanding that manufacturers provide evidence that their biocidal products will not impact on bacterial resistance. Alongside in vitro evidence of potential antimicrobial cross-resistance following biocide exposure, our understanding of the mechanisms of bacterial resistance and, more recently, our understanding of the effect of biocides to induce a mechanism(s) of resistance in bacteria has improved. This article aims to provide an understanding of the development of antimicrobial resistance in bacteria following a biocide exposure. The sections provide evidence of the occurrence of bacterial resistance and its mechanisms of action and debate how to measure bacterial resistance to biocides. Examples pertinent to the veterinary field are used where appropriate.
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19
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Widely Used Benzalkonium Chloride Disinfectants Can Promote Antibiotic Resistance. Appl Environ Microbiol 2018; 84:AEM.01201-18. [PMID: 29959242 DOI: 10.1128/aem.01201-18] [Citation(s) in RCA: 100] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 06/23/2018] [Indexed: 01/15/2023] Open
Abstract
While the misuse of antibiotics has clearly contributed to the emergence and proliferation of resistant bacterial pathogens, with major health consequences, it remains less clear if the widespread use of disinfectants, such as benzalkonium chlorides (BAC), a different class of biocides than antibiotics, has contributed to this problem. Here, we provide evidence that exposure to BAC coselects for antibiotic-resistant bacteria and describe the underlying genetic mechanisms. After inoculation with river sediment, BAC-fed bioreactors selected for several bacterial taxa, including the opportunistic pathogen Pseudomonas aeruginosa, that were more resistant to several antibiotics than their counterparts in a control (no BAC) bioreactor. A metagenomic analysis of the bioreactor microbial communities, confirmed by gene cloning experiments with the derived isolates, suggested that integrative and conjugative elements encoding a BAC efflux pump together with antibiotic resistance genes were responsible for these results. Furthermore, the exposure of the P. aeruginosa isolates to increasing concentrations of BAC selected for mutations in pmrB (polymyxin resistance) and physiological adaptations that contributed to a higher tolerance to polymyxin B and other antibiotics. The physiological adaptations included the overexpression of mexCD-oprJ multidrug efflux pump genes when BAC was added in the growth medium at subinhibitory concentrations. Collectively, our results demonstrated that disinfectants promote antibiotic resistance via several mechanisms and highlight the need to remediate (degrade) disinfectants in nontarget environments to further restrain the spread of antibiotic-resistant bacteria.IMPORTANCE Benzalkonium chlorides (BAC) are biocides broadly used in disinfectant solutions. Disinfectants are widely used in food processing lines, domestic households, and pharmaceutical products and are typically designed to have a different mode of action than antibiotics to avoid interfering with the use of the latter. Whether exposure to BAC makes bacteria more resistant to antibiotics remains an unresolved issue of obvious practical consequences for public health. Using an integrated approach that combines metagenomics of natural microbial communities with gene cloning experiments with isolates and experimental evolution assays, we show that the widely used benzalkonium chloride disinfectants promote clinically relevant antibiotic resistance. Therefore, more attention should be given to the usage of these disinfectants, and their fate in nontarget environments should be monitored more tightly.
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20
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Biofilm formation and susceptibility to biocides of recurring and transient Escherichia coli isolated from meat fabrication equipment. Food Control 2018. [DOI: 10.1016/j.foodcont.2018.02.050] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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21
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Pepper IL, Brooks JP, Gerba CP. Antibiotic Resistant Bacteria in Municipal Wastes: Is There Reason for Concern? ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:3949-3959. [PMID: 29505255 DOI: 10.1021/acs.est.7b04360] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Recently, there has been increased concern about the presence of antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARG), in treated domestic wastewaters, animal manures and municipal biosolids. The concern is whether these additional sources of ARB contribute to antibiotic resistance levels in the environment, that is, "environmental antibiotic resistance." ARB and ARG occur naturally in soil and water, and it remains unclear whether the introduction of ARB in liquid and solid municipal and animal wastes via land application have any significant impact on the background levels of antibiotic resistance in the environment, and whether they affect human exposure to ARB. In this current review, we examine and re-evaluate the incidence of ARB and ARG resulting from land application activities, and offer a new perspective on the threat of antibiotic resistance to public health via exposure from nonclinical environmental sources. Based on inputs of ARBs and ARGs from land application, their fate in soil due to soil microbial ecology principles, and background indigenous levels of ARBs and ARGs already present in soil, we conclude that while antibiotic resistance levels in soil are increased temporally by land application of wastes, their persistence is not guaranteed and is in fact variable, and often contradictory based on application site. Furthermore, the application of wastes may not produce the most direct impact of ARGs and ARB on public health. Further investigation is still warranted in agriculture and public health, including continued scrutiny of antibiotic use in both sectors.
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Affiliation(s)
- Ian L Pepper
- Water and Energy Sustainable Technology Center (WEST) , The University of Arizona , 2959 W. Calle Agua Nueva , Tucson , Arizona 85745 , United States
| | - John P Brooks
- Genetics and Sustainable Agriculture Research Unit, USDA ARS , Mississippi State , Mississippi , 39762 , United States
| | - Charles P Gerba
- Water and Energy Sustainable Technology Center (WEST) , The University of Arizona , 2959 W. Calle Agua Nueva , Tucson , Arizona 85745 , United States
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22
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Ghanem B, Haddadin RN. Multiple drug resistance and biocide resistance in Escherichia coli environmental isolates from hospital and household settings. Antimicrob Resist Infect Control 2018; 7:47. [PMID: 29619214 PMCID: PMC5880012 DOI: 10.1186/s13756-018-0339-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 03/21/2018] [Indexed: 11/21/2022] Open
Abstract
Background Antibiotic resistance of environmental Escherichia coli in hospitals could be increased due to extensive use of biocides resulting in serious infections. In this study, the prevalence of antibiotic resistance of environmental isolates of E. coli from hospitals and household settings were evaluated and compared. In addition, the association between biocide minimum inhibitory concentration (MIC) and multiple drug resistance (MDR) was investigated. Methods Environmental samples were collected from different homes and hospitals in Amman, Jordan. The isolates were identified phenotypically and by PCR. Antibiotic susceptibility tests and MIC of selected biocides were performed on the isolates. Screening for blaCTX-M group 1 was also performed. Results Of 21 E. coli strains isolated, 47.6% were MDR and 67.9% were phenotypically identified as extended spectrum beta-lactamase (ESBL) producers. The occurrence of these ESBL isolates was comparable between household and hospital settings (P > 0.05). The MIC values of the biocides tested against all isolates were well below the in-use concentration of biocides. Moreover, the MICs of biocides were comparable between isolates from households and those from hospitals (P > 0.05). No association was found between MDR and biocide MIC (P > 0.05). Most of ESBL isolates harboured blaCTX-M 1. Conclusions The extensive use of biocides in hospitals is not associated with MDR nor does it affect the MIC of biocides against E.coli.
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Affiliation(s)
- Bothyna Ghanem
- Department of Pharmaceutics and Pharmaceutical Technology, School of Pharmacy, The University of Jordan, Amman, 11942 Jordan
| | - Randa Nayef Haddadin
- Department of Pharmaceutics and Pharmaceutical Technology, School of Pharmacy, The University of Jordan, Amman, 11942 Jordan
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Yueh MF, Tukey RH. Triclosan: A Widespread Environmental Toxicant with Many Biological Effects. Annu Rev Pharmacol Toxicol 2016; 56:251-72. [PMID: 26738475 DOI: 10.1146/annurev-pharmtox-010715-103417] [Citation(s) in RCA: 175] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Triclosan (TCS) is a broad-spectrum antimicrobial agent that has been added to personal care products, including hand soaps and cosmetics, and impregnated in numerous different materials ranging from athletic clothing to food packaging. The constant disposal of TCS into the sewage system is creating a major environmental and public health hazard. Owing to its chemical properties of bioaccumulation and resistance to degradation, TCS is widely detected in various environmental compartments in concentrations ranging from nanograms to micrograms per liter. Epidemiology studies indicate that significant levels of TCS are detected in body fluids in all human age groups. We document here the emerging evidence--from in vitro and in vivo animal studies and environmental toxicology studies--demonstrating that TCS exerts adverse effects on different biological systems through various modes of action. Considering the fact that humans are simultaneously exposed to TCS and many TCS-like chemicals, we speculate that TCS-induced adverse effects may be relevant to human health.
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Affiliation(s)
- Mei-Fei Yueh
- Laboratory of Environmental Toxicology, Department of Chemistry and Biochemistry and Department of Pharmacology, University of California, San Diego, La Jolla, California 92093; ,
| | - Robert H Tukey
- Laboratory of Environmental Toxicology, Department of Chemistry and Biochemistry and Department of Pharmacology, University of California, San Diego, La Jolla, California 92093; ,
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Haque M, Rahman NIA, Zulkifli Z, Ismail S. Antibiotic prescribing and resistance: knowledge level of medical students of clinical years of University Sultan Zainal Abidin, Malaysia. Ther Clin Risk Manag 2016; 12:413-26. [PMID: 27042083 PMCID: PMC4795448 DOI: 10.2147/tcrm.s102013] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
The innovation of penicillin by Dr Alexander Fleming in 1928 and its use in clinical practice saved many lives, especially during the Second World War. Tuberculosis still carries a significant public health threat and has re-emerged over the past two decades, even in modern countries where tuberculosis was thought to be eliminated. The World Health Organization defines antimicrobial resistance as the resistance of a microorganism to an antimicrobial drug that was initially effective for treatment of infections caused by the microbe. Therefore, the findings of the current study will provide data to enable the design of a new educational program to better equip our students in confronting antimicrobial resistance. This study was a cross-sectional, questionnaire-based survey, which was undertaken in the Faculty of Medicine, Universiti Sultan Zainal Abidin, Kuala Terengganu, Malaysia. The study participants were students of the Bachelor of Medicine and Bachelor of Surgery program (MBBS) of Year III, IV, and V. A total of 142 out of 164 (86%) medical students returned the questionnaire. Specifically, the year-wise breakdown of responses was 29% (41), 39% (55), and 32% (45) for Year III, IV, and V, respectively. Among the study respondents, 28% (40) were male, and the remaining 72% (102) were female. In all, 67% of the participants felt more confident in "making an accurate diagnosis of infection/sepsis." The majority (88%) of the study participants stated that they would like more training on antibiotic selection. This research has found that there is a gap between theoretical input and clinical practice; the students are demanding more educational intervention to face the threat of antimicrobial resistance.
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Affiliation(s)
- Mainul Haque
- Faculty of Medicine, Universiti Sultan Zainal Abidin, Kuala Terengganu, Terengganu, Malaysia
| | - Nor Iza A Rahman
- Faculty of Medicine, Universiti Sultan Zainal Abidin, Kuala Terengganu, Terengganu, Malaysia
| | - Zainal Zulkifli
- Faculty of Medicine, Universiti Sultan Zainal Abidin, Kuala Terengganu, Terengganu, Malaysia
| | - Salwani Ismail
- Faculty of Medicine, Universiti Sultan Zainal Abidin, Kuala Terengganu, Terengganu, Malaysia
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Kim SA, Moon H, Lee K, Rhee MS. Bactericidal effects of triclosan in soap both in vitro and in vivo. J Antimicrob Chemother 2015; 70:3345-52. [PMID: 26374612 DOI: 10.1093/jac/dkv275] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/10/2015] [Indexed: 11/12/2022] Open
Abstract
OBJECTIVES On December 2013, the US FDA proposed a rule stating that manufacturers must provide data to demonstrate that antibacterial soap is more effective than plain soap or water. The objective of the present study was to examine the in vitro and in vivo bactericidal effect of triclosan (the most widely used antiseptic agent in soap) in soap. METHODS Twenty bacterial strains (proposed by the FDA) were exposed to plain and antibacterial soaps (the same formulation as plain soap, but containing 0.3% triclosan) for 20 s at 22°C (room temperature) and 40°C (warm temperature). The temperature and time were selected to simulate the hand washing conditions and procedures used by consumers. The triclosan concentration of 0.3% is the maximum allowed by law. The decontamination efficacy of plain soap and antibacterial soap was also examined in vivo: the hands of volunteers were artificially inoculated with Serratia marcescens. RESULTS There was no significant difference (P > 0.05) in bactericidal activity between plain soap and antibacterial soap at either test temperature. However, antibacterial soap showed significantly greater bactericidal effects after 9 h. These results suggest that although triclosan-containing soap does have antibacterial activity, the effects are not apparent during the short time required for hand washing. CONCLUSIONS Antibacterial soap containing triclosan (0.3%) was no more effective than plain soap at reducing bacterial contamination when used under 'real-life' conditions. The present study provides practical information that may prove useful for both industry and governments.
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Affiliation(s)
- S A Kim
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Republic of Korea
| | - H Moon
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Republic of Korea
| | - K Lee
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Republic of Korea
| | - M S Rhee
- Department of Biotechnology, College of Life Sciences and Biotechnology, Korea University, Seoul, 136-713, Republic of Korea
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Dhillon GS, Kaur S, Pulicharla R, Brar SK, Cledón M, Verma M, Surampalli RY. Triclosan: current status, occurrence, environmental risks and bioaccumulation potential. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2015; 12:5657-84. [PMID: 26006133 PMCID: PMC4454990 DOI: 10.3390/ijerph120505657] [Citation(s) in RCA: 268] [Impact Index Per Article: 29.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 05/18/2015] [Accepted: 05/18/2015] [Indexed: 01/14/2023]
Abstract
Triclosan (TCS) is a multi-purpose antimicrobial agent used as a common ingredient in everyday household personal care and consumer products. The expanded use of TCS provides a number of pathways for the compound to enter the environment and it has been detected in sewage treatment plant effluents; surface; ground and drinking water. The physico-chemical properties indicate the bioaccumulation and persistence potential of TCS in the environment. Hence, there is an increasing concern about the presence of TCS in the environment and its potential negative effects on human and animal health. Nevertheless, scarce monitoring data could be one reason for not prioritizing TCS as emerging contaminant. Conventional water and wastewater treatment processes are unable to completely remove the TCS and even form toxic intermediates. Considering the worldwide application of personal care products containing TCS and inefficient removal and its toxic effects on aquatic organisms, the compound should be considered on the priority list of emerging contaminants and its utilization in all products should be regulated.
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Affiliation(s)
| | - Surinder Kaur
- INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, QC G1K 9A9, Canada.
- Department of Mycology & Plant Pathology, Institute of Agricultural Sciences, Banaras Hindu University (BHU), Varanasi-221005, India.
| | - Rama Pulicharla
- INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, QC G1K 9A9, Canada.
| | - Satinder Kaur Brar
- INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, QC G1K 9A9, Canada.
| | - Maximiliano Cledón
- INRS-ETE, Université du Québec, 490, Rue de la Couronne, Québec, QC G1K 9A9, Canada.
- CONICET-IIMyC, National Council of Scientific and Technical Research, C1033AAJ Buenos Aires, Argentina.
| | - Mausam Verma
- CO2 Solutions Inc., 2300, Rue Jean-Perrin, Québec, QC G2C 1T9, Canada.
| | - Rao Y Surampalli
- Department of Civil Engineering, University of Nebraska-Lincoln, N104 SEC P.O. Box 886105, Lincoln, NE 68588, USA.
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Knapp L, Amézquita A, McClure P, Stewart S, Maillard JY. Development of a protocol for predicting bacterial resistance to microbicides. Appl Environ Microbiol 2015; 81:2652-9. [PMID: 25636848 PMCID: PMC4375328 DOI: 10.1128/aem.03843-14] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 01/26/2015] [Indexed: 01/05/2023] Open
Abstract
Regulations dealing with microbicides in Europe and the United States are evolving and now require data on the risk of the development of resistance in organisms targeted by microbicidal products. There is no standard protocol to assess the risk of the development of resistance to microbicidal formulations. This study aimed to validate the use of changes in microbicide and antibiotic susceptibility as initial markers for predicting microbicide resistance and cross-resistance to antibiotics. Three industrial isolates (Pseudomonas aeruginosa, Burkholderia cepacia, and Klebsiella pneumoniae) and two Salmonella enterica serovar Typhimurium strains (SL1344 and 14028S) were exposed to a shampoo, a mouthwash, eye makeup remover, and the microbicides contained within these formulations (chlorhexidine digluconate [CHG] and benzalkonium chloride [BZC]) under realistic, in-use conditions. Baseline and postexposure data were compared. No significant increases in the MIC or the minimum bactericidal concentration (MBC) were observed for any strain after exposure to the three formulations. Increases as high as 100-fold in the MICs and MBCs of CHG and BZC for SL1344 and 14028S were observed but were unstable. Changes in antibiotic susceptibility were not clinically significant. The use of MICs and MBCs combined with antibiotic susceptibility profiling and stability testing generated reproducible data that allowed for an initial prediction of the development of resistance to microbicides. These approaches measure characteristics that are directly relevant to the concern over resistance and cross-resistance development following the use of microbicides. These are low-cost, high-throughput techniques, allowing manufacturers to provide to regulatory bodies, promptly and efficiently, data supporting an early assessment of the risk of resistance development.
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Affiliation(s)
- Laura Knapp
- Cardiff School of Pharmacy and Pharmaceutical Science, Cardiff, Wales, United Kingdom
| | - Alejandro Amézquita
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park, Bedford, United Kingdom
| | - Peter McClure
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park, Bedford, United Kingdom
| | - Sara Stewart
- Unilever Safety and Environmental Assurance Centre, Colworth Science Park, Bedford, United Kingdom
| | - Jean-Yves Maillard
- Cardiff School of Pharmacy and Pharmaceutical Science, Cardiff, Wales, United Kingdom
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Abstract
Quaternary ammonium compounds (QACs) are among the most commonly used disinfectants. There has been concern that their widespread use will lead to the development of resistant organisms, and it has been suggested that limits should be place on their use. While increases in tolerance to QACs have been observed, there is no clear evidence to support the development of resistance to QACs. Since efflux pumps are believe to account for at least some of the increased tolerance found in bacteria, there has been concern that this will enhance the resistance of bacteria to certain antibiotics. QACs are membrane-active agents interacting with the cytoplasmic membrane of bacteria and lipids of viruses. The wide variety of chemical structures possible has seen an evolution in their effectiveness and expansion of applications over the last century, including non-lipid-containing viruses (i.e., noroviruses). Selection of formulations and methods of application have been shown to affect the efficacy of QACs. While numerous laboratory studies on the efficacy of QACs are available, relatively few studies have been conducted to assess their efficacy in practice. Better standardized tests for assessing and defining the differences between increases in tolerance versus resistance are needed. The ecological dynamics of microbial communities where QACs are a main line of defense against exposure to pathogens need to be better understood in terms of sublethal doses and antibiotic resistance.
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Affiliation(s)
- Charles P Gerba
- Department of Soil, Water, and Environmental Science, University of Arizona, Tucson, Arizona, USA
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29
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Burgess C, Desvaux M, Ölmez H. 1st Conference of BacFoodNet: mitigating bacterial colonisation in the food chain: bacterial adhesion, biocide resistance and microbial safety of fresh produce. Res Microbiol 2014; 165:305-10. [DOI: 10.1016/j.resmic.2014.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 03/21/2014] [Indexed: 10/25/2022]
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30
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Taché J, Carpentier B. Hygiene in the home kitchen: Changes in behaviour and impact of key microbiological hazard control measures. Food Control 2014. [DOI: 10.1016/j.foodcont.2013.07.026] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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31
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Borrusso P, Quinlan JJ. Development and Piloting of a Food Safety Audit Tool for the Domestic Environment. Foods 2013; 2:572-584. [PMID: 28239139 PMCID: PMC5302284 DOI: 10.3390/foods2040572] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 11/21/2013] [Accepted: 11/27/2013] [Indexed: 11/17/2022] Open
Abstract
Research suggests that consumers often mishandle food in the home based on survey and observation studies. There is a need for a standardized tool for researchers to objectively evaluate the prevalence and identify the nature of food safety risks in the domestic environment. An audit tool was developed to measure compliance with recommended sanitation, refrigeration and food storage conditions in the domestic kitchen. The tool was piloted by four researchers who independently completed the inspection in 22 homes. Audit tool questions were evaluated for reliability using the κ statistic. Questions that were not sufficiently reliable (κ < 0.5) or did not provide direct evidence of risk were revised or eliminated from the final tool. Piloting the audit tool found good reliability among 18 questions, 6 questions were revised and 28 eliminated, resulting in a final 24 question tool. The audit tool was able to identify potential food safety risks, including evidence of pest infestation (27%), incorrect refrigeration temperature (73%), and lack of hot water (>43 °C, 32%). The audit tool developed here provides an objective measure for researchers to observe and record the most prevalent food safety risks in consumer's kitchens and potentially compare risks among consumers of different demographics.
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Affiliation(s)
- Patricia Borrusso
- Department of Nutrition Sciences, Drexel University, 1505 Race St., Mail Stop 1030, Philadelphia, PA 19102, USA.
| | - Jennifer J Quinlan
- Department of Nutrition Sciences, Drexel University, 1505 Race St., Mail Stop 1030, Philadelphia, PA 19102, USA.
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32
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Maillard JY, Bloomfield S, Coelho JR, Collier P, Cookson B, Fanning S, Hill A, Hartemann P, Mcbain AJ, Oggioni M, Sattar S, Schweizer HP, Threlfall J. Does Microbicide Use in Consumer Products Promote Antimicrobial Resistance? A Critical Review and Recommendations for a Cohesive Approach to Risk Assessment. Microb Drug Resist 2013; 19:344-54. [DOI: 10.1089/mdr.2013.0039] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Affiliation(s)
- Jean-Yves Maillard
- Cardiff School of Pharmacy and Pharmaceutical Sciences, Cardiff University, Cardiff, United Kingdom
| | - Sally Bloomfield
- London School of Hygiene and Tropical Medicine, International Scientific Forum on Home Hygiene, London, United Kingdom
| | | | - Phillip Collier
- School of Contemporary Sciences, University of Abertay Dundee, Dundee, United Kingdom
| | - Barry Cookson
- Division of Infection & Immunity, Faculty of Medical Sciences, University College London, London, United Kingdom
| | - Séamus Fanning
- UCD Centres for Food Safety and Molecular Innovation & Drug Design, School of Public Health, Physiotherapy & Population Science, University College Dublin, Dublin, Ireland
| | - Andrew Hill
- Epidemiology, Surveillance and Risk Group, Animal Health and Veterinary Laboratories Agency, Weybridge, United Kingdom
| | - Philippe Hartemann
- Départment Environment et Santé Publique, Faculté de Médecine, Vandoeuvre-les-Nancy, France
| | - Andrew J. Mcbain
- School of Pharmacy and Pharmaceutical Sciences, the University of Manchester, Manchester, United Kingdom
| | - Marco Oggioni
- Laboratory of Molecular Microbiology and Biotechnology, Università degli Studi di Siena, Siena, Italy
| | - Syed Sattar
- Centre for Research on Environmental Microbiology, University of Ottawa, Ottawa, Ontario, Canada
| | - Herbert P. Schweizer
- Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, Colorado
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Kassem TM, El-Sawy AA, Mohamed AS, Mohamed DE, Abdelhafiz FM. Novel Diphenyl Methane Based Quaternary Ammonium Surfactants: Synthesis, Surface Properties and Antimicrobial Activity. TENSIDE SURFACT DET 2013. [DOI: 10.3139/113.110260] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
A homologous series of cationic gemini diphenyl methane quaternary ammonium salts have been synthesized via chloromethylation of diphenyl methane followed by quaternization using tertiary amines with different chain length. The chemical structures of the prepared surfactants were confirmed using different spectroscopic techniques including, FTIR and 1H-NMR spectra. Surface activity of these compounds have been thoroughly studied and their surface properties including surface and interfacial tension, emulsification power, critical micelle concentration, effectiveness, efficiency, maximum surface excess and minimum surface area were determined. The new synthesized surfactants were screened as antimicrobial agents against different strains of bacteria, yeast and fungi.
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34
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Combination of extracts from Aristolochia cymbifera with streptomycin as a potential antibacterial drug. SPRINGERPLUS 2013; 2:430. [PMID: 24040585 PMCID: PMC3771021 DOI: 10.1186/2193-1801-2-430] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 08/22/2013] [Indexed: 11/19/2022]
Abstract
The appearance of new antibiotic-resistant bacteria is a societal problem that requires the development of new alternative treatments. Therefore, this work evaluated the antibacterial activity of ethanolic (EHI), dichloromethanic (EDI) and hexanic (EHE) extracts from Aristolochia cymbifera stems and the combination of these extracts with an antimicrobial drug to develop a new antibacterial therapy. The EDI, EHE and EHI extracts were obtained by maceration using three different solvents. The minimal inhibitory concentrations (MIC) of these extracts were determined using the microdilution test to determine the antibacterial potential of these extracts and their combination with streptomycin against Staphylococcus aureus, Bacillus cereus, Klebsiella pneumoniae and Shigella flexneri. The extract dose leading to the cytotoxicity of 50% of the cells (CC50) was evaluated using mammalian cells MA104 and the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. The extracts had a MIC under 500 mg/L and a CC50 lower than 50 mg/L. The antibiotic/extract proportion influenced the antibacterial activity of the mixtures, and the proportion that optimized the antibacterial activity of streptomycin was a mixture that contained 75 percent of extract. This composition included less than 6.5 mg/L of extract and 2.5 mg/L of streptomycin and has potential as a new antibacterial therapy.
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35
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Saleh I, Zouhairi O, Alwan N, Hawi A, Barbour E, Harakeh S. Antimicrobial resistance and pathogenicity ofEscherichia coliisolated from common dairy products in the Lebanon. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 2013; 103:39-52. [DOI: 10.1179/136485909x384965] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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36
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Wright O, Stan GB, Ellis T. Building-in biosafety for synthetic biology. Microbiology (Reading) 2013; 159:1221-1235. [DOI: 10.1099/mic.0.066308-0] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Oliver Wright
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Centre for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, UK
| | - Guy-Bart Stan
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Centre for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, UK
| | - Tom Ellis
- Department of Bioengineering, Imperial College London, London SW7 2AZ, UK
- Centre for Synthetic Biology and Innovation, Imperial College London, London SW7 2AZ, UK
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37
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Skovgaard S, Nielsen LN, Larsen MH, Skov RL, Ingmer H, Westh H. Staphylococcus epidermidis isolated in 1965 are more susceptible to triclosan than current isolates. PLoS One 2013; 8:e62197. [PMID: 23614034 PMCID: PMC3628582 DOI: 10.1371/journal.pone.0062197] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 03/18/2013] [Indexed: 01/09/2023] Open
Abstract
Since its introduction to the market in the 1970s, the synthetic biocide triclosan has had widespread use in household and medical products. Although decreased triclosan susceptibility has been observed for several bacterial species, when exposed under laboratory settings, no in vivo studies have associated triclosan use with decreased triclosan susceptibility or cross-resistance to antibiotics. One major challenge of such studies is the lack of strains that with certainty have not been exposed to triclosan. Here we have overcome this challenge by comparing current isolates of the human opportunistic pathogen Staphylococcus epidermidis with isolates collected in the 1960s prior to introduction of triclosan to the market. Of 64 current S. epidermidis isolates 12.5% were found to have tolerance towards triclosan defined as MIC≥0.25 mg/l compared to none of 34 isolates obtained in the 1960s. When passaged in the laboratory in the presence of triclosan, old and current susceptible isolates could be adapted to the same triclosan MIC level as found in current tolerant isolates. DNA sequence analysis revealed that laboratory-adapted strains carried mutations in fabI encoding the enoyl-acyl carrier protein reductase isoform, FabI, that is the target of triclosan, and the expression of fabI was also increased. However, the majority of the tolerant current isolates carried no mutations in fabI or the putative promoter region. Thus, this study indicates that the widespread use of triclosan has resulted in the occurrence of S. epidermidis with tolerance towards triclosan and that the adaptation involves FabI as well as other factors. We suggest increased caution in the general application of triclosan as triclosan has not shown efficacy in reducing infections and is toxic to aquatic organisms.
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Affiliation(s)
- Sissel Skovgaard
- Department of Clinical Microbiology, Hvidovre Hospital, Copenhagen, Denmark
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (SS); (HW)
| | - Lene Nørby Nielsen
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marianne Halberg Larsen
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Robert Leo Skov
- Department of Microbiological Surveillance and Research, Statens Serum Institut, Copenhagen, Denmark
| | - Hanne Ingmer
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Westh
- Department of Clinical Microbiology, Hvidovre Hospital, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- * E-mail: (SS); (HW)
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38
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Biocide tolerance in bacteria. Int J Food Microbiol 2013; 162:13-25. [PMID: 23340387 DOI: 10.1016/j.ijfoodmicro.2012.12.028] [Citation(s) in RCA: 150] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 10/24/2012] [Accepted: 12/15/2012] [Indexed: 02/07/2023]
Abstract
Biocides have been employed for centuries, so today a wide range of compounds showing different levels of antimicrobial activity have become available. At the present time, understanding the mechanisms of action of biocides has also become an important issue with the emergence of bacterial tolerance to biocides and the suggestion that biocide and antibiotic resistance in bacteria might be linked. While most of the mechanisms providing antibiotic resistance are agent specific, providing resistance to a single antimicrobial or class of antimicrobial, there are currently numerous examples of efflux systems that accommodate and, thus, provide tolerance to a broad range of structurally unrelated antimicrobials, both antibiotics and biocides. If biocide tolerance becomes increasingly common and it is linked to antibiotic resistance, not only resistant (even multi-resistant) bacteria could be passed along the food chain, but also there are resistance determinants that can spread and lead to the emergence of new resistant microorganisms, which can only be detected and monitored when the building blocks of resistance traits are understood on the molecular level. This review summarizes the main advances reached in understanding the mechanism of action of biocides, the mechanisms of bacterial resistance to both biocides and antibiotics, and the incidence of biocide tolerance in bacteria of concern to human health and the food industry.
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39
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The frequency of antibiotic-resistant bacteria in homes differing in their use of surface antibacterial agents. Curr Microbiol 2012; 65:407-15. [PMID: 22752336 DOI: 10.1007/s00284-012-0172-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 06/06/2012] [Indexed: 10/28/2022]
Abstract
Antibacterial agents are common in household cleaning and personal care products, but their long-range impacts on commensal and pathogenic household bacteria are largely unknown. In a one-time survey of 38 households from Boston, MA [19] and Cincinnati, OH [18], 13 kitchen and bathroom sites were sampled for total aerobic bacteria and screened for gram phenotype and susceptibility to six antibiotic drug families. The overall bacterial titers of both user (2 or more antibacterial cleaning or personal care products) and non-user (0 or 1 product) rooms were similar with sponges and sink drains consistently showing the highest overall titers and relatively high titers of antibiotic-resistant bacteria. The mean frequency of resistant bacteria ranged from ≤20 % to as high as 45 % and multi-drug resistance was common. However, no significant differences were noted between biocide users and non-users. The frequency of pathogen recovery was similar in both user and non-user groups.
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40
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El-Attar LMR, Scott S, Goh S, Good L. A pestivirus DNA vaccine based on a non-antibiotic resistance Escherichia coli essential gene marker. Vaccine 2011; 30:1702-9. [PMID: 22212129 DOI: 10.1016/j.vaccine.2011.12.078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 12/07/2011] [Accepted: 12/17/2011] [Indexed: 12/26/2022]
Abstract
Antibiotic resistance genes are widely used to produce plasmid DNA vaccines, but risk unwanted exposure to antibiotic residues and the spread of resistance genes. To overcome the limitations of existing selection technologies, we developed an alternative system applying the widely used household biocide triclosan as the selective agent and an endogenous growth essential target gene, fabI, as the plasmid-borne marker in Escherichia coli. The fabI/triclosan system enables efficient, non-antibiotic selection of transformed bacteria, with improved safety and plasmid production features. Here we aimed to evaluate the performance of this non-antibiotic selection system using a plasmid DNA vaccine against bovine viral diarrhoea virus as an example. The new system displayed high-yield plasmid DNA production in a standard E. coli host strain and growth media. Notably, the purified pDNA provided efficient in vitro protein expression and a strong in vivo neutralising antibody response in a mouse model, with measures comparable to that of the parental plasmid DNA based on ampicillin resistance. The fabI/triclosan system requires only low levels of triclosan for selection (1 μM) and residual triclosan in isolated DNA was below the limit of detection (< 20 parts per trillion). The fabI/triclosan selection system provides a simple, non-antibiotic resistance marker for plasmid selection, applicable to DNA vaccines and possibly other recombinant vaccine applications.
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Affiliation(s)
- Laila M R El-Attar
- Department of Pathology and Infectious Diseases, Royal Veterinary College, University of London, North Mymms, Hertfordshire AL9 7TA, UK.
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41
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Leaper D, Assadian O, Hubner NO, McBain A, Barbolt T, Rothenburger S, Wilson P. Antimicrobial sutures and prevention of surgical site infection: assessment of the safety of the antiseptic triclosan. Int Wound J 2011; 8:556-66. [PMID: 21854548 PMCID: PMC7950790 DOI: 10.1111/j.1742-481x.2011.00841.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
This article is based on a second Hygienist Panel meeting held in London on 16-17 June 2010. The Panel discussed the current use of antimicrobials and care bundles in the prevention of surgical site infection; the need to comply with good antibiotic stewardship, to reduce the risk of antibiotic-resistant and emergent organisms; and the need to revisit the use of antiseptics. The discussion was driven by concerns of the use of triclosan, which had been raised by a publication from the Scientific Committee on Consumer Products of the Directorate General for Health and Consumers, European Commission. Uncertainties that excessive use of triclosan for preservation and in cosmetics could select naturally resistant environmental organisms or induce reduced triclosan-susceptibility or antibiotic resistance were considered. It was concluded that the uses of triclosan with demonstrable health benefits, as in some medical applications (such as antimicrobial sutures), need to be distinguished from those where there is no proven benefit, such as its use in certain consumer products. The addition of triclosan to a product must be substantiated in any claim of preventive or therapeutic health benefit. Triclosan is the most widely studied biocide and this same level of information should be available for other topically used antimicrobials, which are widely used in surgical practice and chronic wound care.
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Affiliation(s)
- David Leaper
- Department of Dermatology and Wound Healing, Cardiff University, Cardiff, UK.
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42
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Dann AB, Hontela A. Triclosan: environmental exposure, toxicity and mechanisms of action. J Appl Toxicol 2011; 31:285-311. [PMID: 21462230 DOI: 10.1002/jat.1660] [Citation(s) in RCA: 532] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Triclosan [5-chloro-2-(2,4-dichlorophenoxy)phenol; TCS] is a broad spectrum antibacterial agent used in personal care, veterinary, industrial and household products. TCS is commonly detected in aquatic ecosystems, as it is only partially removed during the wastewater treatment process. Sorption, biodegradation and photolytic degradation mitigate the availability of TCS to aquatic biota; however the by-products such as methyltriclosan and other chlorinated phenols may be more resistant to degradation and have higher toxicity than the parent compound. The continuous exposure of aquatic organisms to TCS, coupled with its bioaccumulation potential, have led to detectable levels of the antimicrobial in a number of aquatic species. TCS has been also detected in breast milk, urine and plasma, with levels of TCS in the blood correlating with consumer use patterns of the antimicrobial. Mammalian systemic toxicity studies indicate that TCS is neither acutely toxic, mutagenic, carcinogenic, nor a developmental toxicant. Recently, however, concern has been raised over TCS's potential for endocrine disruption, as the antimicrobial has been shown to disrupt thyroid hormone homeostasis and possibly the reproductive axis. Moreover, there is strong evidence that aquatic species such as algae, invertebrates and certain types of fish are much more sensitive to TCS than mammals. TCS is highly toxic to algae and exerts reproductive and developmental effects in some fish. The potential for endocrine disruption and antibiotic cross-resistance highlights the importance of the judicious use of TCS, whereby the use of TCS should be limited to applications where it has been shown to be effective.
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Affiliation(s)
- Andrea B Dann
- Department of Biological Sciences, Alberta Water and Environmental Science Bldg, 4401 University Dr. W., University of Lethbridge, Lethbridge, Alberta, Canada
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43
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Cole MR, Li M, El-Zahab B, Janes ME, Hayes D, Warner IM. Design, synthesis, and biological evaluation of β-lactam antibiotic-based imidazolium- and pyridinium-type ionic liquids. Chem Biol Drug Des 2011; 78:33-41. [PMID: 21443681 DOI: 10.1111/j.1747-0285.2011.01114.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We herein report the preparation and investigation of antibacterial activity of biocidal ionic liquids (ILs) consisting of cationic imidazolium or pyridinium and an anionic β-lactam antibiotic. The antibacterial properties were quantified by measuring the minimum inhibitory concentration and minimum bactericidal concentration against Escherichia coli O157:H7, Klebsiella pneumoniae, Staphylococcus aureus, and Enterococcus faecium. In general, the ILs had improved antibacterial activity than their parent materials, whether individually or in combination. In 83% of the experiments, the ampicillin ILs (Amp-ILs) had better antibacterial activities than their quaternary halide parent materials, whereas in 92% of the experiments, Amp-ILs outperformed the commercially available sodium ampicillin salt. Amp-ILs had up to 43 times improved antibacterial activity than sodium ampicillin. Overall, when normalized for ampicillin content, ILs had greater antimicrobial activity against E. coli O157:H7, K. pneumoniae, S. aureus, and E. faecium than sodium ampicillin alone.
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Affiliation(s)
- Marsha R Cole
- Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA
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44
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Hoefer D, Hammer TR. Antimicrobial active clothes display no adverse effects on the ecological balance of the healthy human skin microflora. ISRN DERMATOLOGY 2011; 2011:369603. [PMID: 22363849 PMCID: PMC3262534 DOI: 10.5402/2011/369603] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Accepted: 02/27/2011] [Indexed: 11/23/2022]
Abstract
The progressive public use of antimicrobial clothes has raised issues concerning skin health. A placebo-controlled side-to-side study was run with antimicrobial clothes versus fabrics of similar structure but minus the antimicrobial activity, to evaluate possible adverse effects on the healthy skin microflora. Sixty volunteers were enrolled. Each participant received a set of form-fitting T-shirts constructed in 2 halves: an antibacterial half, displaying activities of 3–5 log-step reductions due to silver-finishes or silver-loaded fibres and a nonantibacterial control side. The microflora of the scapular skin was analyzed weekly for opportunistic and pathogenic microorganisms over six weeks. The antibacterial halves did not disturb the microflora in number or composition, whereas a silver-containing deodorant displayed a short-term disturbance. Furthermore, parameters of skin morphology and function (TEWL, pH, moisture) did not show any significant shifts. In summary, antimicrobial clothes did not show adverse effects on the ecological balance of the healthy skin microflora.
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Affiliation(s)
- Dirk Hoefer
- Institute for Hygiene and Biotechnology, Hohenstein Institutes, Schloss Hohenstein, 74357 Boennigheim, Germany
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45
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Mc Cay PH, Ocampo-Sosa AA, Fleming GTA. Effect of subinhibitory concentrations of benzalkonium chloride on the competitiveness of Pseudomonas aeruginosa grown in continuous culture. Microbiology (Reading) 2010; 156:30-38. [DOI: 10.1099/mic.0.029751-0] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
This study investigates the link between adaptation to biocides and antibiotics in Pseudomonas aeruginosa. An enrichment continuous culture of P. aeruginosa NCIMB 10421 (MIC 25 mg BKC l−1) was operated (D=0.04 h−1, 792 h) with added benzalkonium chloride (BKC). A derivative, PA-29 (696 h), demonstrated a >12-fold decrease in sensitivity to the biocide (MIC >350 mg BKC l−1). The variant demonstrated a 256-fold increase in resistance to ciprofloxacin, with a mutation in the gyrA gene (Thr-83→Ile). Similarly, culturing of the original strain in a continuous-culture system with ciprofloxacin selection pressure led to the evolution of BKC-adapted populations (MIC 100 mg BKC l−1). Efflux pump activity predominantly contributed to the developed phenotype of PA-29. An amino acid substitution (Val-51→Ala) in nfxB, the Mex efflux system regulator gene, was observed for PA-29. Overexpression of both MexAB-OprM and MexCD-OprJ was recorded for PA-29. Similarly, mexR, a repressor of the Mex system, was downregulated. Competition studies were carried out in continuous culture between PA-29 and the original strain (in the presence of subinhibitory concentrations of BKC). The outcome of competition was influenced by the concentration of biocide used and the nature of limiting nutrient. The inclusion of 1 mg BKC l−1 in the medium feed was sufficient to select (S=0.011) for the BKC-adapted strain in magnesium-limited culture. Conversely, the presence of 10 mg BKC l−1 in the medium supply was insufficient to select for the same organism (S=−0.017) in the glucose-limited culture. These results indicate the importance of environmental conditions on selection and maintenance of biocide adaptation.
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Affiliation(s)
- Paul H. Mc Cay
- Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Alain A. Ocampo-Sosa
- Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Gerard T. A. Fleming
- Department of Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
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Lamichhane-Khadka R, Riordan JT, Delgado A, Muthaiyan A, Reynolds TD, Wilkinson BJ, Gustafson JE. Genetic changes that correlate with the pine-oil disinfectant-reduced susceptibility mechanism of Staphylococcus aureus. J Appl Microbiol 2009; 105:1973-81. [PMID: 19120644 DOI: 10.1111/j.1365-2672.2008.03956.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS To identify factors associated with the Staphylococcus aureus pine-oil disinfectant-reduced-susceptibility (PD(RS)) mechanism and to describe one possible PD(RS) model. METHODS AND RESULTS Comparative genomic sequencing (CGS) and microarray analysis were utilized to detect mutations and transcriptome alterations that occur in a S. aureus PD(RS) mutant. Mutant analysis, antimicrobial gradient plates, growth studies and 3-hydroxy-3-methylglutaryl coenzyme A synthase assays were then performed to confirm the biological consequences of the 'omics' alterations detected in a PD(RS) mutant. CGS uncovered three mutations in a PD(RS) mutant in a(n): alcohol dehydrogenase (adh), catabolite control protein A (ccpA) and an NADPH-flavin oxidoreductase (frp). These mutations lead to increased growth rates; increased transcription of an NAD-dependent D-lactate dehydrogenase gene (ddh); and increased flux through the mevalonate pathway. PD(RS) mutants demonstrated reduced susceptibility to bacitracin and farnesol, and one PD(RS) mutant displayed upregulation of bacA, a bacitracin-resistance gene. Collectively, this evidence demonstrates altered undecaprenol metabolism in PD(RS) mutants. CONCLUSIONS The PD(RS) mechanism proposed results from increased catabolic capabilities and increased flux through the mevalonate pathway as well as altered bactoprenol physiology. SIGNIFICANCE AND IMPACT OF THE STUDY A novel mechanism that bacteria utilize to overcome the killing effects of PD formulations is proposed that is unique from the PD(RS) mechanism of the enterobacteraciae.
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Affiliation(s)
- R Lamichhane-Khadka
- Department of Biology, New Mexico State University, Las Cruces, NM 88003-8001, USA
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Cerf O, Carpentier B, Sanders P. Tests for determining in-use concentrations of antibiotics and disinfectants are based on entirely different concepts: "resistance" has different meanings. Int J Food Microbiol 2009; 136:247-54. [PMID: 19853944 DOI: 10.1016/j.ijfoodmicro.2009.10.002] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 09/28/2009] [Accepted: 10/01/2009] [Indexed: 02/07/2023]
Abstract
There are concerns that more extensive application of disinfectants in the food industry could result in increased resistance of bacteria to antibiotics and that therapeutic failure could ensue. This paper highlights the differences in application and mode of action between antibiotics in human or animal medicine and disinfectants in the food industry. It describes the completely different methods used to determine in-use concentrations in the two contexts. It points out that the minimum inhibitory concentration (MIC) is never the concentration at which disinfectants should be applied. It also discusses erroneous conclusions that may be drawn when the failure of therapy or disinfection is attributed to intrinsic properties of the molecules rather than to misuse of antibiotics or disinfectants. The paper suggests that the intended meaning of the word "resistance" be carefully defined in scientific articles with due reference to the measurement mentioned in the abstract and possibly reflected in the title. It also suggests that in matters of disinfection the word "resistance" be preferred when the phenomenon being studied is killing and "tolerance" when it is the adaptation to inhibitory concentrations.
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Affiliation(s)
- O Cerf
- Epidemiology and Risk Analysis, Alfort Veterinary School, 7 avenue du Général de Gaulle, FR-94700 Maisons-Alfort, France.
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Is there a role for triclosan/copolymer toothpaste in the management of periodontal disease? Br Dent J 2009; 207:117-25. [DOI: 10.1038/sj.bdj.2009.669] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/22/2009] [Indexed: 11/08/2022]
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Scott E, Duty S, McCue K. A critical evaluation of methicillin-resistant Staphylococcus aureus and other bacteria of medical interest on commonly touched household surfaces in relation to household demographics. Am J Infect Control 2009; 37:447-53. [PMID: 19361887 DOI: 10.1016/j.ajic.2008.12.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Revised: 12/01/2008] [Accepted: 12/02/2008] [Indexed: 10/20/2022]
Abstract
BACKGROUND We sought to characterize and quantify bacteria of medical interest on commonly touched household surfaces and to evaluate predictors such as employment, day care attendance, and presence of infants and pets. METHODS A convenience sample of 35 homes was recruited from the metro-Boston area, and up to 32 surfaces were sampled in kitchens, bathrooms, and living areas. RESULTS Highest bacterial counts were associated with wet sites including hand/skin contact surfaces such as the tub, kitchen sink, and faucet handles. Surfaces were found to be contaminated with the bacteria of medical interest including species of Enterobacteriaceae, Pseudomonas, methicillin-sensitive Staphyloccus aureus (MSSA), and methicillin-resistant Staphyloccus aureus (MRSA). CONCLUSION A number of hand/skin contact surfaces were found to be frequently contaminated with one or more of the bacteria of medical interest. The presence of a cat in the home was found to be a strong predictor for the isolation of MRSA. This study provides further insight about microorganisms of medical interest on surfaces in American homes and the impact of factors that can influence bacterial contamination. The study may indicate that cleaning in private homes should be directed to the areas pinpointed by the study as very rich in bacteria of potential medical importance.
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Goh S, Good L. Plasmid selection in Escherichia coli using an endogenous essential gene marker. BMC Biotechnol 2008; 8:61. [PMID: 18694482 PMCID: PMC2527308 DOI: 10.1186/1472-6750-8-61] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2008] [Accepted: 08/11/2008] [Indexed: 12/04/2022] Open
Abstract
Background Antibiotic resistance genes are widely used for selection of recombinant bacteria, but their use risks contributing to the spread of antibiotic resistance. In particular, the practice is inappropriate for some intrinsically resistant bacteria and in vaccine production, and costly for industrial scale production. Non-antibiotic systems are available, but require mutant host strains, defined media or expensive reagents. An unexplored concept is over-expression of a host essential gene to enable selection in the presence of a chemical inhibitor of the gene product. To test this idea in E. coli, we used the growth essential target gene fabI as the plasmid-borne marker and the biocide triclosan as the selective agent. Results The new cloning vector, pFab, enabled selection by triclosan at 1 μM. Interestingly, pFab out-performed the parent pUC19-ampicillin system in cell growth, plasmid stability and plasmid yield. Also, pFab was toxic to host cells in a way that was reversed by triclosan. Therefore, pFab and triclosan are toxic when used alone but in combination they enhance growth and plasmid production through a gene-inhibitor interaction. Conclusion The fabI-triclosan model system provides an alternative plasmid selection method based on essential gene over-expression, without the use of antibiotic-resistance genes and conventional antibiotics.
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Affiliation(s)
- Shan Goh
- Department of Cell and Molecular Biology, Karolinska Institute, Stockholm, SE-17177, Sweden.
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