1
|
Bolten S, Lott TT, Ralyea RD, Gianforte A, Trmcic A, Orsi RH, Martin NH, Wiedmann M. Intensive Environmental Sampling and Whole Genome Sequence-based Characterization of Listeria in Small- and Medium-sized Dairy Facilities Reveal Opportunities for Simplified and Size-appropriate Environmental Monitoring Strategies. J Food Prot 2024; 87:100254. [PMID: 38417482 DOI: 10.1016/j.jfp.2024.100254] [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: 12/14/2023] [Revised: 02/17/2024] [Accepted: 02/21/2024] [Indexed: 03/01/2024]
Abstract
Small- and medium-sized dairy processing facilities (SMDFs) may face unique challenges with respect to controlling Listeria in their processing environments, e.g., due to limited resources. The aim of this study was to implement and evaluate environmental monitoring programs (EMPs) for Listeria control in eight SMDFs in a ∼1-year longitudinal study; this included a comparison of pre-operation (i.e., after cleaning and sanitation and prior to production) and mid-operation (i.e., at least 4 h into production) sampling strategies. Among 2,072 environmental sponge samples collected across all facilities, 272 (13%) were positive for Listeria. Listeria prevalence among pre- and mid-operation samples (15% and 17%, respectively), was not significantly different. Whole genome sequencing (WGS) performed on select isolates to characterize Listeria persistence patterns revealed repeated isolation of closely related Listeria isolates (i.e., ≤20 high-quality single nucleotide polymorphism [hqSNP] differences) in 5/8 facilities over >6 months, suggesting Listeria persistence and/or reintroduction was relatively common among the SMDFs evaluated here. WGS furthermore showed that for 41 sites where samples collected pre- and mid-operation were positive for Listeria, Listeria isolates obtained were highly related (i.e., ≤10 hqSNP differences), suggesting that pre-operation sampling alone may be sufficient and more effective for detecting sites of Listeria persistence. Importantly, our data also showed that only 1/8 of facilities showed a significant decrease in Listeria prevalence over 1 year, indicating continued challenges with Listeria control in at least some SMDFs. We conclude that options for simplified Listeria EMPs (e.g., with a focus on pre-operation sampling, which allows for more rapid identification of likely persistence sites) may be valuable for improved Listeria control in SMDFs.
Collapse
Affiliation(s)
- Samantha Bolten
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853, USA; Food Safety Laboratory, Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Timothy T Lott
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Robert D Ralyea
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Anika Gianforte
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Aljosa Trmcic
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Renato H Orsi
- Food Safety Laboratory, Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Nicole H Martin
- Milk Quality Improvement Program, Department of Food Science, Cornell University, Ithaca, NY 14853, USA
| | - Martin Wiedmann
- Food Safety Laboratory, Department of Food Science, Cornell University, Ithaca, NY 14853, USA.
| |
Collapse
|
2
|
Lin LC, Kao CY, Chang SC, Hidrosollo JH, Lu JJ. Molecular characterization of lugdunin inactivation mechanisms and their association with Staphylococcus lugdunensis genetic types. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2024; 57:278-287. [PMID: 38296696 DOI: 10.1016/j.jmii.2024.01.005] [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: 09/21/2023] [Revised: 01/03/2024] [Accepted: 01/09/2024] [Indexed: 02/02/2024]
Abstract
BACKGROUND AND PURPOSE Our previous studies showed that lugdunin activities are associated with Staphylococcus lugdunensis genotypes, and most isolates do not exhibit lugdunin activity. As a continuation of our previous analysis, we focused on the reasons for defects in lugdunin production in S. lugdunensis clinical isolates. METHODS A comparative analysis of 36 S. lugdunensis whole genome sequencing data revealed three major mutation types, unknown deletion mechanism that caused most of lug operon genes lost, mobile genetic element (MGE) insertion, and nonsense mutations, which potentially damaged lugdunin production. A total of 152 S. lugdunensis clinical isolates belonging to lugdunin nonproducers were further examined for the above three mutation types. PCR products were sequenced to examine these variations. RESULTS Forty-six of the 152 isolates were CRISPR-Cas IIC isolates, including 26 ST27, 14 ST4, and 6 ST29 isolates; further investigation confirmed that all of their lug operons had lost almost all lug operon genes except lugM. An IS256 insertion in lugA was identified in 16 isolates, and most isolates (15 over 16) belonged to ST3. In addition, three nonsense mutations caused by single nucleotide substitutions (an adenine deletion in lugB at the 361th and 1219th nucleotides and an adenine deletion in lugC at the 1612nd nucleotide) that were frequently observed among 36 S. lugdunensis whole genome sequencing data were further observed in our clinical isolates. These three nonsense mutations were frequently found in most of CRISPR-Cas IIIA strains, especially in ST6 isolates. CONCLUSION Our findings suggest that the mechanisms affecting lugdunin production are associated with S. lugdunensis molecular types.
Collapse
Affiliation(s)
- Lee-Chung Lin
- Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Cheng-Yen Kao
- Institute of Microbiology and Immunology, College of Life Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shih-Cheng Chang
- Department of Medical Laboratory, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Jazon Harl Hidrosollo
- Institute of Microbiology and Immunology, College of Life Sciences, National Yang Ming Chiao Tung University, Taipei, Taiwan; University of San Agustin, College of Pharmacy and Medical Technology, Iloilo City, Philippines
| | - Jang-Jih Lu
- Department of Laboratory Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan; Department of Medical Biotechnology and Laboratory Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan; Department of Medicine, College of Medicine, Chang Gung University, Taoyuan, Taiwan.
| |
Collapse
|
3
|
Magagna G, Finazzi G, Filipello V. Newly Designed Primers for the Sequencing of the inlA Gene of Lineage I and II Listeria monocytogenes Isolates. Int J Mol Sci 2022; 23:ijms232214106. [PMID: 36430584 PMCID: PMC9698914 DOI: 10.3390/ijms232214106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 11/14/2022] [Accepted: 11/14/2022] [Indexed: 11/17/2022] Open
Abstract
Listeria monocytogenes is a major human foodborne pathogen responsible for listeriosis. The virulence factor Internalin A (inlA) has a key role in the invasion of L. monocytogenes into the human intestinal epithelium, and the presence of premature stop-codons (PMSC) mutations in the inlA gene sequence is correlated with attenuated virulence. The inlA sequencing process is carried out by dividing the gene into three sections which are then reassembled to obtain the full gene. The primers available however were only able to entirely amplify the lineage II isolates. In this study, we present a set of new primers which allow inlA sequencing of isolates belonging to both lineages, since lineage I isolates are the ones most frequently associated to clinical cases. Using newly designed primers, we assessed the presence of inlA PMSCs in food, food processing environments and clinical isolates.
Collapse
Affiliation(s)
- Giulia Magagna
- Food Safety Department, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna (IZSLER), Via A. Bianchi 9, 25124 Brescia, Italy
- Correspondence: ; Tel.: +39-0302-2906-11
| | - Guido Finazzi
- Food Safety Department, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna (IZSLER), Via A. Bianchi 9, 25124 Brescia, Italy
- Centro di Referenza Nazionale per i Rischi Emergenti in Sicurezza Alimentare—CRESA, Via A. Bianchi 9, 25124 Brescia, Italy
| | - Virginia Filipello
- Food Safety Department, Istituto Zooprofilattico Sperimentale della Lombardia e dell’Emilia Romagna (IZSLER), Via A. Bianchi 9, 25124 Brescia, Italy
| |
Collapse
|
4
|
Wu J, NicAogáin K, McAuliffe O, Jordan K, O’Byrne C. Phylogenetic and Phenotypic Analyses of a Collection of Food and Clinical Listeria monocytogenes Isolates Reveal Loss of Function of Sigma B from Several Clonal Complexes. Appl Environ Microbiol 2022; 88:e0005122. [PMID: 35481758 PMCID: PMC9128516 DOI: 10.1128/aem.00051-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 03/17/2022] [Indexed: 12/14/2022] Open
Abstract
To understand the molecular mechanisms that contribute to the stress responses of the important foodborne pathogen Listeria monocytogenes, we collected 139 strains (meat, n = 25; dairy, n = 10; vegetable, n = 8; seafood, n = 14; mixed food, n = 4; and food processing environments, n = 78), mostly isolated in Ireland, and subjected them to whole-genome sequencing. These strains were compared to 25 Irish clinical isolates and 4 well-studied reference strains. Core genome and pan-genome analysis confirmed a highly clonal and deeply branched population structure. Multilocus sequence typing showed that this collection contained a diverse range of strains from L. monocytogenes lineages I and II. Several groups of isolates with highly similar genome content were traced to single or multiple food business operators, providing evidence of strain persistence or prevalence, respectively. Phenotypic screening assays for tolerance to salt stress and resistance to acid stress revealed variants within several clonal complexes that were phenotypically distinct. Five of these phenotypic outliers were found to carry mutations in the sigB operon, which encodes the stress-inducible sigma factor sigma B. Transcriptional analysis confirmed that three of the strains that carried mutations in sigB, rsbV, or rsbU had reduced SigB activity, as predicted. These strains exhibited increased tolerance to salt stress and displayed decreased resistance to low pH stress. Overall, this study shows that loss-of-function mutations in the sigB operon are comparatively common in field isolates, probably reflecting the cost of the general stress response to reproductive fitness in this pathogen. IMPORTANCE The bacterial foodborne pathogen Listeria monocytogenes frequently contaminates various categories of food products and is able to cause life-threatening infections when ingested by humans. Thus, it is important to control the growth of this bacterium in food by understanding the mechanisms that allow its proliferation under suboptimal conditions. In this study, intraspecies heterogeneity in stress response was observed across a collection consisting of mainly Irish L. monocytogenes isolates. Through comparisons of genome sequence and phenotypes observed, we identified three strains with impairment of the general stress response regulator SigB. Two of these strains are used widely in food challenge studies for evaluating the growth potential of L. monocytogenes. Given that loss of SigB function is associated with atypical phenotypic properties, the use of these strains in food challenge studies should be re-evaluated.
Collapse
Affiliation(s)
- Jialun Wu
- Bacterial Stress Response Group, Microbiology, School of Biological and Chemical Sciences, National University of Ireland, Galway, Ireland
| | - Kerrie NicAogáin
- Bacterial Stress Response Group, Microbiology, School of Biological and Chemical Sciences, National University of Ireland, Galway, Ireland
| | | | - Kieran Jordan
- Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
| | - Conor O’Byrne
- Bacterial Stress Response Group, Microbiology, School of Biological and Chemical Sciences, National University of Ireland, Galway, Ireland
| |
Collapse
|
5
|
Prevalence and Clonal Diversity of over 1,200 Listeria monocytogenes Isolates Collected from Public Access Waters near Produce Production Areas on the Central California Coast during 2011 to 2016. Appl Environ Microbiol 2022; 88:e0035722. [PMID: 35377164 DOI: 10.1128/aem.00357-22] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A 5-year survey of public access surface waters in an agricultural region of the Central California Coast was done to assess the prevalence of the foodborne pathogen Listeria monocytogenes. In nature, L. monocytogenes lives as a saprophyte in soil and water, which are reservoirs for contamination of preharvest produce. Moore swabs were deployed biweekly in lakes, ponds, streams, and rivers during 2011 to 2016. L. monocytogenes was recovered in 1,224 of 2,922 samples, resulting in 41.9% prevalence. Multiple subtypes were isolated from 97 samples, resulting in 1,323 L. monocytogenes isolates. Prevalence was higher in winter and spring and after rain events in some waterways. Over 84% of the isolates were serotype 4b. Whole-genome sequencing was done on 1,248 isolates, and in silico multilocus sequence typing revealed 74 different sequence types (STs) and 39 clonal complexes (CCs). The clones most isolated, CC639, CC183, and CC1, made up 27%, 19%, and 13%, respectively, of the sequenced isolates. Other types were CC663, CC6, CC842, CC4, CC2, CC5, and CC217. All sequenced isolates contained intact copies of core L. monocytogenes virulence genes, and pathogenicity islands LIPI-3 and LIPI-4 were identified in 73% and 63%, respectively, of the sequenced isolates. The virulence factor internalin A was predicted to be intact in all but four isolates, while genes important for sanitizer and heavy metal resistance were found in <5% of the isolates. These waters are not used for crop irrigation directly, but they are available to wildlife and can flood fields during heavy rains. IMPORTANCE Listeria monocytogenes serotype 4b and 1/2a strains are implicated in most listeriosis, and hypervirulent listeriosis stems from strains containing pathogenicity islands LIPI-3 and LIPI-4. The waters and sediments in the Central California Coast agricultural region contain widespread and diverse L. monocytogenes populations, and all the isolates contain intact virulence genes. Emerging clones CC183 and CC639 were the most abundant clones, and major clones CC1, CC4, and CC6 were well represented. CC183 was responsible for three produce-related outbreaks in the last 7 years. Most of the isolates in the survey differ from those of lesser virulence that are often isolated from foods and food processing plants because they contain genes encoding an intact virulence factor, internalin A, and most did not contain genes for sanitizer and heavy metal resistance. This isolate collection is important for understanding L. monocytogenes populations in agricultural and natural regions.
Collapse
|
6
|
Iglesias MA, Kroning IS, Ramires T, Cunha CEP, Moreira GMSG, Camargo AC, Mendonça M, Nero LA, Conceição FR, Lopes GV, DA Silva WP. Genetic Profiles and Invasion Ability of Listeria monocytogenes Isolated from Bovine Carcasses in Southern Brazil. J Food Prot 2022; 85:591-596. [PMID: 34995347 DOI: 10.4315/jfp-21-345] [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: 09/06/2021] [Accepted: 01/05/2022] [Indexed: 11/11/2022]
Abstract
ABSTRACT The goals of this study were to evaluate the persistence and the virulence potential of Listeria monocytogenes isolated from beef carcasses obtained in processing facilities in the southern region of Rio Grande do Sul, Brazil, based on pulsed-field gel electrophoresis (PFGE), invasion ability in human colorectal carcinoma cells (HCT-116), internalin A (InlA) expression by Western blot, and identification of mutation points in inlA. PFGE profiles demonstrated that L. monocytogenes isolates were grouped based on their previously identified lineages and serogroups (lineage I: serogroup IIb, n = 2, and serogroup IVb, n = 5; lineage II: serogroup IIc, n = 5). Isolates with indistinguishable genetic profiles through this method were obtained from different slaughterhouses and sampling steps, with as much as a 3-year interval. Seven isolates showed high invasion ability (2.4 to 7.4%; lineage I, n = 6, and lineage II, n = 1) in HCT and expressed InlA. Five isolates showed low cell invasion ability (0.6 to 1.4%; lineage I, n = 1, and lineage II, n = 4) and did not express InlA, and two of them (lineage II, serogroup IIc) presented mutations in inlA that led to premature stop codon type 19 at position 326 (GAA → TAA). The results demonstrated that most L. monocytogenes isolates from lineage I expressed InlA and were the most invasive in HCT, indicating their high virulence potential, whereas most isolates from lineage II showed attenuated invasion because of nonexpression of InlA or the presence of premature stop codon type 19 in inlA. The obtained results demonstrated that L. monocytogenes with indistinguishable PFGE profiles can persist or be reintroduced in beef processing facilities in the studied region and that differences in their virulence potential are based on their lineages and serogroups. HIGHLIGHTS
Collapse
Affiliation(s)
- Mariana A Iglesias
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Isabela S Kroning
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Tassiana Ramires
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Carlos E P Cunha
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Gustavo M S G Moreira
- Technische Universität Braunschweig, Institut für Biochemie, Biotechnologie und Bioinformatik, Abteilung Biotechnologie, Spielmannstraße 7, 38106 Braunschweig, Germany
| | - Anderson C Camargo
- Departamento de Tecnologia de Alimentos, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Marcelo Mendonça
- Programa de Pós-Graduação em Sanidade e Reprodução de Animais de Produção, Universidade Federal Rural do Agreste de Pernambuco, Garanhuns, Pernambuco, Brazil
| | - Luís Augusto Nero
- Departamento de Veterinária, Universidade Federal de Viçosa, Viçosa, Minas Gerais, Brazil
| | - Fabricio R Conceição
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Graciela Volz Lopes
- Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil
| | - Wladimir Padilha DA Silva
- Centro de Desenvolvimento Tecnológico, Núcleo de Biotecnologia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil.,Departamento de Ciência e Tecnologia Agroindustrial, Faculdade de Agronomia, Universidade Federal de Pelotas, Pelotas, Rio Grande do Sul, Brazil
| |
Collapse
|
7
|
Chen T, Orsi RH, Chen R, Gunderson M, Roof S, Wiedmann M, Childs-Sanford SE, Cummings KJ. Characterization of Listeria monocytogenes isolated from wildlife in central New York. Vet Med Sci 2022; 8:1319-1329. [PMID: 35113496 PMCID: PMC9122436 DOI: 10.1002/vms3.758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Background Listeria monocytogenes (Lm) present in farming soil and food‐processing facilities threatens food safety, but little is known about the carriage of Lm by wildlife. Objectives We estimated the prevalence of faecal Lm shedding among wildlife admitted to a veterinary medical teaching hospital in central New York and characterized a subset of the Lm isolates. Methods Wildlife samples were collected between May 2018 and December 2019. We characterized the Lm isolates by assessing the growth at three temperatures approximating the body temperatures of reptiles (25°C), mammals (37°C), and birds (42°C) and identifying genotypic characteristics related to transmission and virulence. Results The apparent prevalence of faecal Lm shedding was 5.6% [18/324; 95% confidence interval (CI), 3.3%–8.6%]. Among 13 isolates that represented two lineages and 11 clonal complexes, three and five isolates were grouped into the same SNP clusters with human clinical isolates and environmental isolates, respectively. However, specific SNP difference data showed that Lm from wildlife was generally not closely related (>22 SNP differences) to Lm from human clinical sources and the food‐processing environment. While the stress response locus SSI‐2 was absent, SSI‐1 was found in four isolates. Virulence genes prfA, plcA, hly, mpl, actA, plcB, inlA, inlB, inlC, inlE, inlH, inlJ, and inlK were present, without any premature stop codons, in all isolates. Virulence loci Listeria pathogenicity island 3 (LIPI‐3) and LIPI‐4, which have been linked to hypervirulence, and inlG were found in four, three, and seven isolates, respectively. Conclusions Wildlife represents a potential reservoir for genetically diverse and putatively hypervirulent Lm strains. No statistically significant association between growth parameters and hosts was observed. However, compared to lineage I isolates, lineage II isolates showed significantly (p < 0.05) faster growth at 25°C and significantly slower growth at 42°C, suggesting that wildlife Lm isolates that belong to lineages I and II differ in their ability to grow at 25°C and 42°C.
Collapse
Affiliation(s)
- Tong Chen
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
| | - Renato H Orsi
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
| | - Ruixi Chen
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
| | - Maureen Gunderson
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
| | - Sherry Roof
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
| | - Martin Wiedmann
- Department of Food Science, College of Agriculture and Life Sciences, Cornell University, Ithaca, New York, USA
| | - Sara E Childs-Sanford
- Department of Clinical Sciences, College of Veterinary Medicine, Cornell University, NY, USA
| | - Kevin J Cummings
- Department of Public and Ecosystem Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, USA
| |
Collapse
|
8
|
Comparative Genome Analysis Reveals Accumulation of Single-Nucleotide Repeats in Pathogenic Escherichia Lineages. Curr Issues Mol Biol 2022; 44:498-504. [PMID: 35723320 PMCID: PMC8928963 DOI: 10.3390/cimb44020034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/13/2022] [Accepted: 01/17/2022] [Indexed: 11/17/2022] Open
Abstract
Homopolymeric tracts (HPTs) can lead to phase variation and DNA replication slippage, driving adaptation to environmental changes and evolution of genes and genomes. However, there is limited information on HPTs in Escherichia; therefore, we conducted a comprehensive cross-strain search for HPTs in Escherichia genomes. We determined the HPT genomic distribution and identified a pattern of high-frequency HPT localization in pathogenic Escherichia lineages. Notably, HPTs localized near transcriptional regulatory genes. Additionally, excessive repeats accumulated in toxin-coding genes. Moreover, the genomic localization of some HPTs might be derived from exogenous DNA, such as that of bacteriophages. Altogether, our findings may prove useful for understanding the role of HPTs in Escherichia genomes.
Collapse
|
9
|
Agostinho Davanzo EF, dos Santos RL, Castro VHDL, Palma JM, Pribul BR, Dallago BSL, Fuga B, Medeiros M, Titze de Almeida SS, da Costa HMB, Rodrigues DDP, Lincopan N, Perecmanis S, Santana AP. Molecular characterization of Salmonella spp. and Listeria monocytogenes strains from biofilms in cattle and poultry slaughterhouses located in the federal District and State of Goiás, Brazil. PLoS One 2021; 16:e0259687. [PMID: 34767604 PMCID: PMC8589217 DOI: 10.1371/journal.pone.0259687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 10/23/2021] [Indexed: 10/26/2022] Open
Abstract
Listeria monocytogenes and Salmonella spp. are considered important foodborne pathogens that are commonly associated with foods of animal origin. The aim of this study was to perform molecular characterization of L. monocytogenes and Salmonella spp. isolated from biofilms of cattle and poultry slaughterhouses located in the Federal District and State of Goiás, Brazil. Fourteen L. monocytogenes isolates and one Salmonella sp. were detected in poultry slaughterhouses. No isolates were detected in cattle slaughterhouses. All L. monocytogenes isolates belonged to lineage II, and 11 different pulsotypes were detected. Pulsed-field gel electrophoresis analysis revealed the dissemination of two strains within one plant, in addition to the regional dissemination of one of them. The Salmonella isolate was identified via whole genome sequencing as Salmonella enterica serovar Minnesota ST548. In the sequence analysis, no premature stop codons were detected in the inlA gene of Listeria. All isolates demonstrated the ability to adhere to Caco-2 cells, while 50% were capable of invading them. Antimicrobial resistance was detected in 57.1% of the L. monocytogenes isolates, and resistance to sulfonamide was the most common feature. The tetC, ermB, and tetM genes were detected, and four isolates were classified as multidrug-resistant. Salmonella sp. was resistant to nine antimicrobials and was classified as multidrug-resistant. Resistance genes qnrB19, blaCMY-2, aac(6')-Iaa, sul2, and tetA, and a mutation in the parC gene were detected. The majority (78.5%) of the L. monocytogenes isolates were capable of forming biofilms after incubation at 37°C for 24 h, and 64.3% were capable of forming biofilms after incubation at 12°C for 168 h. There was no statistical difference in the biofilm-forming capacity under the different evaluated conditions. Salmonella sp. was capable of forming biofilms at both tested temperatures. Biofilm characterization was confirmed by collecting the samples consistently, at the same sampling points, and by assessing biofilm formation in vitro. These results highlight the potential risk of cross-contamination in poultry slaughterhouses and the importance of surveillance and pathogen control maintenance programs within the meat production industry.
Collapse
Affiliation(s)
| | | | | | - Joana Marchesini Palma
- Faculty of Agronomy and Veterinary Medicine, University of Brasília (UnB), Brasília, DF, Brazil
| | - Bruno Rocha Pribul
- National Reference Laboratory for Bacterial Enteric Infections, Oswaldo Cruz Institute, Manguinhos, Rio de Janeiro, RJ, Brazil
| | | | - Bruna Fuga
- Laboratory of Bacterial Resistance and Therapeutic Alternatives, Biomedical Sciences Institute, University of São Paulo, São Paulo, SP, Brazil
| | - Margareti Medeiros
- Faculty of Agronomy and Veterinary Medicine, University of Brasília (UnB), Brasília, DF, Brazil
| | | | | | - Dália dos Prazeres Rodrigues
- National Reference Laboratory for Bacterial Enteric Infections, Oswaldo Cruz Institute, Manguinhos, Rio de Janeiro, RJ, Brazil
| | - Nilton Lincopan
- Laboratory of Bacterial Resistance and Therapeutic Alternatives, Biomedical Sciences Institute, University of São Paulo, São Paulo, SP, Brazil
| | - Simone Perecmanis
- Faculty of Agronomy and Veterinary Medicine, University of Brasília (UnB), Brasília, DF, Brazil
| | - Angela Patrícia Santana
- Faculty of Agronomy and Veterinary Medicine, University of Brasília (UnB), Brasília, DF, Brazil
| |
Collapse
|
10
|
Farber JM, Zwietering M, Wiedmann M, Schaffner D, Hedberg CW, Harrison MA, Hartnett E, Chapman B, Donnelly CW, Goodburn KE, Gummalla S. Alternative approaches to the risk management of Listeria monocytogenes in low risk foods. Food Control 2021. [DOI: 10.1016/j.foodcont.2020.107601] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
11
|
Medeiros M, Castro VHLD, Mota ALADA, Pereira MG, De Martinis ECP, Perecmanis S, Santana AP. Assessment of Internalin A Gene Sequences and Cell Adhesion and Invasion Capacity of Listeria monocytogenes Strains Isolated from Foods of Animal and Related Origins. Foodborne Pathog Dis 2020; 18:243-252. [PMID: 33337940 DOI: 10.1089/fpd.2020.2855] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Listeria monocytogenes is a foodborne pathogen of global relevance that causes outbreaks and sporadic cases of listeriosis, acquired through the consumption of contaminated products, including milk or meat products and ready-to-eat meat products subjected to intensive handling. The objective of the present study was to classify L. monocytogenes isolated from various food-related sources in the Federal District of Brazil and surrounding areas to sequence internalin A (inlA) genes from these isolates and assess their adhesion and invasion capacity using Caco-2 cells. In addition, 15 were classified as group I, 3 as group II, and 7 classified as group IV. Premature stop codons (PMSCs) at the nucleotide position 976 (GAA→TAA) of the inlA gene were identified in 5 of the 25 isolates. Adhesion and invasion tests in Caco-2 cells showed that all the isolates were capable of adhesion and cellular invasion, with isolates containing PMSCs exhibiting on average higher invasion capacity than those without PMSCs (p = 0.041) and a median of adhesion very distinctive from those without stop codons. These results are the first report of PMSCs in the inlA gene of L. monocytogenes from the Federal District of Brazil and Brazil.
Collapse
Affiliation(s)
- Margareti Medeiros
- Food Molecular Microbiology Laboratory, ASS 128/10, Faculty of Agronomy and Veterinary Medicine, University of Brasília (UnB), Brasília, Brazil
| | - Virgilio Hipolito Lemos de Castro
- Food Molecular Microbiology Laboratory, ASS 128/10, Faculty of Agronomy and Veterinary Medicine, University of Brasília (UnB), Brasília, Brazil
| | - Ana Lourdes Arrais de Alencar Mota
- Food Molecular Microbiology Laboratory, ASS 128/10, Faculty of Agronomy and Veterinary Medicine, University of Brasília (UnB), Brasília, Brazil
| | | | | | - Simone Perecmanis
- Food Molecular Microbiology Laboratory, ASS 128/10, Faculty of Agronomy and Veterinary Medicine, University of Brasília (UnB), Brasília, Brazil
| | - Angela Patricia Santana
- Food Molecular Microbiology Laboratory, ASS 128/10, Faculty of Agronomy and Veterinary Medicine, University of Brasília (UnB), Brasília, Brazil
| |
Collapse
|
12
|
Guerreiro DN, Wu J, Dessaux C, Oliveira AH, Tiensuu T, Gudynaite D, Marinho CM, Boyd A, García-Del Portillo F, Johansson J, O'Byrne CP. Mild Stress Conditions during Laboratory Culture Promote the Proliferation of Mutations That Negatively Affect Sigma B Activity in Listeria monocytogenes. J Bacteriol 2020; 202:e00751-19. [PMID: 32094160 PMCID: PMC7148139 DOI: 10.1128/jb.00751-19] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 02/01/2020] [Indexed: 12/18/2022] Open
Abstract
In Listeria monocytogenes, the full details of how stress signals are integrated into the σB regulatory pathway are not yet available. To help shed light on this question, we investigated a collection of transposon mutants that were predicted to have compromised activity of the alternative sigma factor B (σB). These mutants were tested for acid tolerance, a trait that is known to be under σB regulation, and they were found to display increased acid sensitivity, similar to a mutant lacking σB (ΔsigB). The transposon insertions were confirmed by whole-genome sequencing, but in each case, the strains were also found to carry a frameshift mutation in the sigB operon. The changes were predicted to result in premature stop codons, with negative consequences for σB activation, independently of the transposon location. Reduced σB activation in these mutants was confirmed. Growth measurements under conditions similar to those used during the construction of the transposon library revealed that the frameshifted sigB operon alleles conferred a growth advantage at higher temperatures, during late exponential phase. Mixed-culture experiments at 42°C demonstrated that the loss of σB activity allowed mutants to take over a population of parental bacteria. Together, our results suggest that mutations affecting σB activity can arise during laboratory culture because of the growth advantage conferred by these mutations under mild stress conditions. The data highlight the significant cost of stress protection in this foodborne pathogen and emphasize the need for whole-genome sequence analysis of newly constructed strains to confirm the expected genotype.IMPORTANCE In the present study, we investigated a collection of Listeria monocytogenes strains that all carried sigB operon mutations. The mutants all had reduced σB activity and were found to have a growth advantage under conditions of mild heat stress (42°C). In mixed cultures, these mutants outcompeted the wild type when mild heat stress was present but not at an optimal growth temperature. An analysis of 22,340 published L. monocytogenes genome sequences found a high rate of premature stop codons present in genes positively regulating σB activity. Together, these findings suggest that the occurrence of mutations that attenuate σB activity can be favored under conditions of mild stress, probably highlighting the burden on cellular resources that stems from deploying the general stress response.
Collapse
Affiliation(s)
- Duarte N Guerreiro
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Jialun Wu
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| | - Charlotte Dessaux
- Laboratory of Intracellular Bacterial Pathogens, National Center for Biotechnology (CNB)-CSIC, Madrid, Spain
| | - Ana H Oliveira
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Center of Microbial Research, Umeå, Sweden
| | - Teresa Tiensuu
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Center of Microbial Research, Umeå, Sweden
| | - Diana Gudynaite
- Molecular Microbiology Department, School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Catarina M Marinho
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
- Université Bourgogne Franche-Conté, Dijon, France
- Institut National de la Recherche Agronomique, UMR Agroécologie, Dijon, France
| | - Aoife Boyd
- Pathogenic Mechanisms Research Group, National University of Ireland, Galway, Ireland
| | | | - Jörgen Johansson
- Laboratory for Molecular Infection Medicine Sweden, Department of Molecular Biology, Umeå Center of Microbial Research, Umeå, Sweden
| | - Conor P O'Byrne
- Bacterial Stress Response Group, Microbiology, School of Natural Sciences, National University of Ireland, Galway, Ireland
| |
Collapse
|
13
|
Evolution of Listeria monocytogenes in a Food Processing Plant Involves Limited Single-Nucleotide Substitutions but Considerable Diversification by Gain and Loss of Prophages. Appl Environ Microbiol 2020; 86:AEM.02493-19. [PMID: 31900305 PMCID: PMC7054086 DOI: 10.1128/aem.02493-19] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 12/20/2019] [Indexed: 12/23/2022] Open
Abstract
Knowledge about the genetic evolution of L. monocytogenes in food processing facilities over multiple years is generally lacking. This information is critical to interpret WGS findings involving food or food-associated isolates. This study suggests that L. monocytogenes that persists in processing facilities may evolve with a low single-nucleotide mutation rate mostly driven by negative (i.e., purifying) selection but with rapid diversification of prophages. Hence, isolation of L. monocytogenes with few single-nucleotide polymorphism (SNP) differences in different locations (e.g., supplier plants and receiving plants) is possible, highlighting the importance of epidemiological and detailed isolate metadata for interpreting WGS data in traceback investigation. Our study also shows how advanced WGS data analyses can be used to support root cause analysis efforts and may, for example, pinpoint the time when a persistence event started (which then potentially could be linked to facility changes, introduction of new equipment, etc.). Whole-genome sequencing (WGS) is becoming the standard method for subtyping Listeria monocytogenes. Interpretation of WGS data for isolates from foods and associated environments is, however, challenging due to a lack of detailed data on Listeria evolution in processing facilities. Here, we used previously collected WGS data for 40 L. monocytogenes isolates obtained from a cold-smoked salmon processing facility between 1998 and 2015 to probe the L. monocytogenes molecular evolution in this facility, combined with phenotypic assessment of selected isolates. Isolates represented three clusters (1, 2, and 3); cluster 3 isolates (n = 32) were obtained over 18 years. The average mutation rate for cluster 3 was estimated as 1.15 × 10−7 changes per nucleotide per year (∼0.35 changes per genome per year); the most recent common ancestors (MRCAs) of subclusters 3a and 3b were estimated to have occurred around 1958 and 1974, respectively, within the age of the facility, suggesting long-term persistence in this facility. Extensive prophage diversity was observed within subclusters 3a and 3b, which have one shared and six unique prophage profiles for each subcluster (with 16 prophage profiles found among all 40 isolates). The plasmid-borne sanitizer tolerance operon bcrABC was found in all cluster 2 and 3 isolates, while the transposon-borne sanitizer tolerance gene qacH was found in one cluster 1 isolate; presence of these genes was correlated with the ability to survive increased concentrations of sanitizers. Selected isolates showed significant variation in the ability to attach to surfaces, with persistent isolates attaching better than transient isolates at 21°C. IMPORTANCE Knowledge about the genetic evolution of L. monocytogenes in food processing facilities over multiple years is generally lacking. This information is critical to interpret WGS findings involving food or food-associated isolates. This study suggests that L. monocytogenes that persists in processing facilities may evolve with a low single-nucleotide mutation rate mostly driven by negative (i.e., purifying) selection but with rapid diversification of prophages. Hence, isolation of L. monocytogenes with few single-nucleotide polymorphism (SNP) differences in different locations (e.g., supplier plants and receiving plants) is possible, highlighting the importance of epidemiological and detailed isolate metadata for interpreting WGS data in traceback investigation. Our study also shows how advanced WGS data analyses can be used to support root cause analysis efforts and may, for example, pinpoint the time when a persistence event started (which then potentially could be linked to facility changes, introduction of new equipment, etc.).
Collapse
|
14
|
A Structural Study on the Listeria Monocytogenes Internalin A-Human E-cadherin Interaction: A Molecular Tool to Investigate the Effects of Missense Mutations. Toxins (Basel) 2020; 12:toxins12010060. [PMID: 31968631 PMCID: PMC7020427 DOI: 10.3390/toxins12010060] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/14/2020] [Accepted: 01/16/2020] [Indexed: 02/07/2023] Open
Abstract
Listeria monocytogenes is a widespread foodborne pathogen of high concern and internalin A is an important virulence factor that mediates cell invasion upon the interaction with the host protein E-cadherin. Nonsense mutations of internalin A are known to reduce virulence. Although missense mutations are largely overlooked, they need to be investigated in respect to their effects in cell invasion processes. This work presented a computational workflow to early characterize internalin A missense mutations. The method reliably estimated the effects of a set of engineered missense mutations in terms of their effects on internalin A–E-cadherin interaction. Then, the effects of mutations of an internalin A variant from a L. monocytogenes isolate were calculated. Mutations showed impairing effects on complex stability providing a mechanistic explanation of the low cells invasion capacity previously observed. Overall, our results provided a rational approach to explain the effects of internalin A missense mutations. Moreover, our findings highlighted that the strength of interaction may not directly relate to the cell invasion capacity reflecting the non-exclusive role of internalin A in determining the virulence of L. monocytogenes. The workflow could be extended to other virulence factors providing a promising platform to support a better molecular understanding of L. monocytogenes epidemiology.
Collapse
|
15
|
Su X, Cao G, Zhang J, Pan H, Zhang D, Kuang D, Yang X, Xu X, Shi X, Meng J. Characterization of internalin genes in Listeria monocytogenes from food and humans, and their association with the invasion of Caco-2 cells. Gut Pathog 2019; 11:30. [PMID: 31198443 PMCID: PMC6558679 DOI: 10.1186/s13099-019-0307-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 05/29/2019] [Indexed: 02/07/2023] Open
Abstract
Background Internalins are surface proteins that are utilized by Listeria monocytogenes to facilitate its invasion into human intestinal epithelial cells. The expression of a full-length InlA is one of essential virulence factors for L. monocytogenes to cross the intestinal barrier in order to invade epithelial cells. Results In this study, the gene sequences of inlA in 120 L. monocytogenes isolates from food (n = 107) and humans (n = 13) were analyzed. Premature stop codon (PMSC) mutations in inlA were identified in 51 isolates (50 from food and 1 from human). Six mutation types of PMSCs were identified. Among the 51 isolates with PMSCs in inlA, there were 44 serogroup 1/2c, 3c isolates from food, of which seven belonged to serogroups 1/2a, 3a. A total of 153,382 SNPs in 2247 core genes from 42 genomes were identified and used to construct a phylogenetic tree. Serotype 1/2c isolates with inlA PMSC mutations were grouped together. Cell culture studies on 21 isolates showed that the invasion to Caco-2 cells was significantly reduced among isolates with inlA PMSC mutations compared to those without PMSC mutations (P < 0.01). The PMSC mutations in inlA correlated with the inability of the L. monocytogenes isolates to invade Caco-2 cells (Pearson’s coefficient 0.927, P < 0.01). Conclusion Overall, the study has revealed the reduced ability of L. monocytogenes to invade human intestinal epithelial cells in vitro was linked to the presence of PMSC mutations in inlA. Isolates with PMSC mutations shared the same genomic characteristics indicating the genetic basis on the potential virulence of L. monocytogenes invasion. Electronic supplementary material The online version of this article (10.1186/s13099-019-0307-8) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- Xudong Su
- 1Department of Food Science and Technology, MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Guojie Cao
- 2Department of Nutrition & Food Science, University of Maryland, College Park, MD 20742 USA
| | - Jianmin Zhang
- 1Department of Food Science and Technology, MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Haijian Pan
- 1Department of Food Science and Technology, MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Daofeng Zhang
- 1Department of Food Science and Technology, MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Dai Kuang
- 1Department of Food Science and Technology, MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Xiaowei Yang
- 1Department of Food Science and Technology, MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Xuebin Xu
- 3Shanghai Municipal Center for Disease Control and Prevention, Shanghai, 200336 China
| | - Xianming Shi
- 1Department of Food Science and Technology, MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, State Key Lab of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, 200240 China
| | - Jianghong Meng
- 2Department of Nutrition & Food Science, University of Maryland, College Park, MD 20742 USA
| |
Collapse
|
16
|
Soni DK, Ghosh A, Chikara SK, Singh KM, Joshi CG, Dubey SK. Comparative whole genome analysis of Listeria monocytogenes 4b strains reveals least genome diversification irrespective of their niche specificity. GENE REPORTS 2017. [DOI: 10.1016/j.genrep.2017.05.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
|
17
|
Genetic Stability and Evolution of the sigB Allele, Used for Listeria Sensu Stricto Subtyping and Phylogenetic Inference. Appl Environ Microbiol 2017; 83:AEM.00306-17. [PMID: 28389543 DOI: 10.1128/aem.00306-17] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/03/2017] [Indexed: 11/20/2022] Open
Abstract
Sequencing of single genes remains an important tool that allows the rapid classification of bacteria. Sequencing of a portion of sigB, which encodes a stress-responsive alternative sigma factor, has emerged as a commonly used molecular tool for the initial characterization of diverse Listeria isolates. In this study, evolutionary approaches were used to assess the validity of sigB allelic typing for Listeria For a data set of 4,280 isolates, sigB allelic typing showed a Simpson's index of diversity of 0.96. Analyses of 164 sigB allelic types (ATs) found among the 6 Listeriasensu stricto species, representing these 4,280 isolates, indicate that neither frequent homologous recombination nor positive selection significantly contributed to the evolution of sigB, confirming its genetic stability. The molecular clock test provided evidence for unequal evolution rates across clades; Listeria welshimeri displayed the lowest sigB diversity and was the only species in which sigB evolved in a clocklike manner, implying a unique natural history. Among the four L. monocytogenes lineages, sigB evolution followed a molecular clock only in lineage IV. Moreover, sigB displayed a significant negative Tajima D value in lineage II, suggesting a recent population bottleneck followed by lineage expansion. The absence of positive selection along with the violation of the molecular clock suggested a nearly neutral mechanism of Listeriasensu strictosigB evolution. While comparison with a whole-genome sequence-based phylogeny revealed that the sigB phylogeny did not correctly reflect the ancestry of L. monocytogenes lineage IV, the availability of a large sigB AT database allowed accurate species classification.IMPORTANCEsigB allelic typing has been widely used for species delineation and subtyping of Listeria However, an informative evaluation of this method from an evolutionary perspective was missing. Our data indicate that the genetic stability of sigB is affected by neither frequent homologous recombination nor positive selection, which supports that sigB allelic typing provides reliable subtyping and classification of Listeria sensu stricto strains. However, multigene data are required for accurate phylogeny reconstruction of Listeria This study thus contributes to a better understanding of the evolution of sigB and confirms the robustness of the sigB subtyping system for Listeria.
Collapse
|
18
|
Ferreira da Silva M, Ferreira V, Magalhães R, Almeida G, Alves A, Teixeira P. Detection of premature stop codons leading to truncated internalin A among food and clinical strains of Listeria monocytogenes. Food Microbiol 2017; 63:6-11. [DOI: 10.1016/j.fm.2016.10.033] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2016] [Revised: 08/31/2016] [Accepted: 10/24/2016] [Indexed: 11/26/2022]
|
19
|
Hingston P, Chen J, Dhillon BK, Laing C, Bertelli C, Gannon V, Tasara T, Allen K, Brinkman FSL, Truelstrup Hansen L, Wang S. Genotypes Associated with Listeria monocytogenes Isolates Displaying Impaired or Enhanced Tolerances to Cold, Salt, Acid, or Desiccation Stress. Front Microbiol 2017; 8:369. [PMID: 28337186 PMCID: PMC5340757 DOI: 10.3389/fmicb.2017.00369] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/22/2017] [Indexed: 01/11/2023] Open
Abstract
The human pathogen Listeria monocytogenes is a large concern in the food industry where its continuous detection in food products has caused a string of recalls in North America and Europe. Most recognized for its ability to grow in foods during refrigerated storage, L. monocytogenes can also tolerate several other food-related stresses with some strains possessing higher levels of tolerances than others. The objective of this study was to use a combination of phenotypic analyses and whole genome sequencing to elucidate potential relationships between L. monocytogenes genotypes and food-related stress tolerance phenotypes. To accomplish this, 166 L. monocytogenes isolates were sequenced and evaluated for their ability to grow in cold (4°C), salt (6% NaCl, 25°C), and acid (pH 5, 25°C) stress conditions as well as survive desiccation (33% RH, 20°C). The results revealed that the stress tolerance of L. monocytogenes is associated with serotype, clonal complex (CC), full length inlA profiles, and the presence of a plasmid which was identified in 55% of isolates. Isolates with full length inlA exhibited significantly (p < 0.001) enhanced cold tolerance relative to those harboring a premature stop codon (PMSC) in this gene. Similarly, isolates possessing a plasmid demonstrated significantly (p = 0.013) enhanced acid tolerance. We also identified nine new L. monocytogenes sequence types, a new inlA PMSC, and several connections between CCs and the presence/absence or variations of specific genetic elements. A whole genome single-nucleotide-variants phylogeny revealed sporadic distribution of tolerant isolates and closely related sensitive and tolerant isolates, highlighting that minor genetic differences can influence the stress tolerance of L. monocytogenes. Specifically, a number of cold and desiccation sensitive isolates contained PMSCs in σB regulator genes (rsbS, rsbU, rsbV). Collectively, the results suggest that knowing the sequence type of an isolate in addition to screening for the presence of full-length inlA and a plasmid, could help food processors and food agency investigators determine why certain isolates might be persisting in a food processing environment. Additionally, increased sequencing of L. monocytogenes isolates in combination with stress tolerance profiling, will enhance the ability to identify genetic elements associated with higher risk strains.
Collapse
Affiliation(s)
- Patricia Hingston
- Department of Food, Nutrition, and Health, University of British ColumbiaVancouver, BC, Canada
| | - Jessica Chen
- Department of Food, Nutrition, and Health, University of British ColumbiaVancouver, BC, Canada
| | - Bhavjinder K. Dhillon
- Department of Molecular Biology and Biochemistry, Simon Fraser UniversityBurnaby, BC, Canada
| | - Chad Laing
- Laboratory for Foodborne Zoonoses, Public Health Agency of CanadaLethbridge, AB, Canada
| | - Claire Bertelli
- Department of Molecular Biology and Biochemistry, Simon Fraser UniversityBurnaby, BC, Canada
| | - Victor Gannon
- Laboratory for Foodborne Zoonoses, Public Health Agency of CanadaLethbridge, AB, Canada
| | - Taurai Tasara
- Institute for Food Safety and Hygiene, University of ZurichZurich, Switzerland
| | - Kevin Allen
- Department of Food, Nutrition, and Health, University of British ColumbiaVancouver, BC, Canada
| | - Fiona S. L. Brinkman
- Department of Molecular Biology and Biochemistry, Simon Fraser UniversityBurnaby, BC, Canada
| | - Lisbeth Truelstrup Hansen
- Division for Microbiology and Production, National Food Institute, Technical University of DenmarkKongens Lyngby, Denmark
| | - Siyun Wang
- Department of Food, Nutrition, and Health, University of British ColumbiaVancouver, BC, Canada
| |
Collapse
|
20
|
Gorski L, Parker CT, Liang AS, Walker S, Romanolo KF. The Majority of Genotypes of the Virulence Gene inlA Are Intact among Natural Watershed Isolates of Listeria monocytogenes from the Central California Coast. PLoS One 2016; 11:e0167566. [PMID: 27907153 PMCID: PMC5131979 DOI: 10.1371/journal.pone.0167566] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Accepted: 11/16/2016] [Indexed: 11/24/2022] Open
Abstract
Internalin A is an essential virulence gene involved in the uptake of the foodborne pathogen Listeria monocytogenes into host cells. It is intact in clinical strains and often truncated due to Premature Stop Codons (PMSCs) in isolates from processed foods and processing facilities. Less information is known about environmental isolates. We sequenced the inlA alleles and did Multi Locus Variable Number Tandem Repeat Analysis (MLVA) on 112 L. monocytogenes isolates from a 3-year period from naturally contaminated watersheds near a leafy green growing area in Central California. The collection contained 14 serotype 1/2a, 12 serotype 1/2b, and 86 serotype 4b strains. Twenty-seven different inlA alleles were found. Twenty-three of the alleles are predicted to encode intact copies of InlA, while three contain PMSCs. Another allele has a 9-nucleotide deletion, previously described for a clinical strain, indicating that it is still functional. Intact inlA genes were found in 101 isolates, and 8 isolates contained the allele predicted to contain the 3-amino acid deletion. Both allele types were found throughout the 3-year sampling period. Three strains contained inlA alleles with PMSCs, and these were found only during the first 3 months of the study. SNP analysis of the intact alleles indicated clustering of alleles based on serotype and lineage with serotypes 1/2b and 4b (lineage I strains) clustering together, and serotype 1/2a (lineage II strains) clustering separately. The combination of serotype, MLVA types, and inlA allele types indicate that the 112 isolates reflect at least 49 different strains of L. monocytogenes. The finding that 90% of environmental L. monocytogenes isolates contain intact inlA alleles varies significantly from isolates found in processing plants. This information is important to public health labs and growers as to the varieties of L. monocytogenes that could potentially contaminate fresh produce in the field by various means.
Collapse
Affiliation(s)
- Lisa Gorski
- Produce Safety and Microbiology Research Unit, USDA, Agricultural Research Service, Albany, CA
- * E-mail:
| | - Craig T. Parker
- Produce Safety and Microbiology Research Unit, USDA, Agricultural Research Service, Albany, CA
| | - Anita S. Liang
- Produce Safety and Microbiology Research Unit, USDA, Agricultural Research Service, Albany, CA
| | - Samarpita Walker
- Produce Safety and Microbiology Research Unit, USDA, Agricultural Research Service, Albany, CA
| | - Kelly F. Romanolo
- Produce Safety and Microbiology Research Unit, USDA, Agricultural Research Service, Albany, CA
| |
Collapse
|
21
|
VAN Stelten A, Roberts AR, Manuel CS, Nightingale KK. Listeria monocytogenes Isolates Carrying Virulence-Attenuating Mutations in Internalin A Are Commonly Isolated from Ready-to-Eat Food Processing Plant and Retail Environments. J Food Prot 2016; 79:1733-1740. [PMID: 28221857 DOI: 10.4315/0362-028x.jfp-16-145] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Listeria monocytogenes is a human foodborne pathogen that may cause an invasive disease known as listeriosis in susceptible individuals. Internalin A (InlA; encoded by inlA) is a virulence factor that facilitates crossing of host cell barriers by L. monocytogenes . At least 19 single nucleotide polymorphisms (SNPs) in inlA that result in a premature stop codon (PMSC) have been described worldwide. SNPs leading to a PMSC in inlA have been shown to be causally associated with attenuated virulence. L. monocytogenes pathogens carrying virulence-attenuating (VA) mutations in inlA have been commonly isolated from ready-to-eat (RTE) foods but rarely have been associated with human disease. This study was conducted to determine the prevalence of VA SNPs in inlA among L. monocytogenes from environments associated with RTE food production and handling. More than 700 L. monocytogenes isolates from RTE food processing plant (n = 409) and retail (n = 319) environments were screened for the presence of VA SNPs in inlA. Overall, 26.4% of isolates from RTE food processing plant and 32.6% of isolates from retail environments carried a VA mutation in inlA. Food contact surfaces sampled at retail establishments were significantly (P < 0.0001) more likely to be contaminated by a L. monocytogenes isolate carrying a VA mutation in inlA (56% of 55 isolates) compared with nonfood contact surfaces (28% of 264 isolates). Overall, a significant proportion of L. monocytogenes isolated from RTE food production and handling environments have reduced virulence. These data will be useful in the revision of current and the development of future risk assessments that incorporate strain-specific virulence parameters.
Collapse
Affiliation(s)
- A VAN Stelten
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523.,Department of Animal and Food Sciences, Texas Tech University, Lubbock, Texas 79409
| | - A R Roberts
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523.,Department of Biological and Physical Sciences, Montana State University, Billings, Montana 59101
| | - C S Manuel
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523.,Department of Food, Bioprocessing and Nutrition Sciences, North Carolina State University, Raleigh, North Carolina 27695, USA
| | - K K Nightingale
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523
| |
Collapse
|
22
|
Kamau LM, Skilton RA, Githaka N, Kiara H, Kabiru E, Shah T, Musoke AJ, Bishop RP. Extensive polymorphism of Ra86 genes in field populations of Rhipicephalus appendiculatus from Kenya. Ticks Tick Borne Dis 2016; 7:772-781. [PMID: 27051976 DOI: 10.1016/j.ttbdis.2016.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 03/15/2016] [Accepted: 03/16/2016] [Indexed: 10/22/2022]
Abstract
Commercial vaccines based on recombinant forms of the Bm86 tick gut antigen are used to control the southern cattle tick, Rhipicephalus microplus, a 1-host species, in Australia and Latin America. We describe herein sequence polymorphism in genes encoding Ra86 homologues of Bm86 in the brown ear tick, Rhipicephalus appendiculatus, isolated from four Kenyan field populations and one laboratory colony. Sequencing of 19 Ra86 sequences defined two alleles differentiated by indels, encoding 693 amino acids (aa) and 654 aa respectively, from the Muguga laboratory reference strain. Ra86 sequences were also determined from gut cDNA from four field populations of R. appendiculatus collected in different livestock production systems in Kenya. Analysis of approximately 20 Ra86 sequences from each of the four field sites in central and Western Kenya; Makuyu, Kiambu, Kakamega and Uasin Gishu, revealed three additional size types differentiated by 39-49 amino acid indels resulting in a total of 5 indel-defined genotypes. The 693 aa type 5 was isolated only from the laboratory tick stock; genotypes 1, 2 and 3 were identified in ticks from the four Kenyan field sites and appeared to be derivatives of the shorter RA86 genotype found in Muguga laboratory stock genotype 4. By contrast no large indels have yet been observed between R. microplus sequences from Australia, South America or Africa. Evidence that selection contributes to the observed sequence variation was provided by analysis of ratio of synonymous and non-synonymous substitutions and application of the selective neutrality and neutral evolution tests to the primary data. Phylogenetic analysis clustered sequences from all Ra86 size types and Bm86, into four major clades based on amino acid substitutions, but there was no evidence that these groupings correlated with geographical separation of R. appendiculatus populations.
Collapse
Affiliation(s)
- L M Kamau
- Department of Zoological Sciences, Kenyatta University, P.O. Box 43844, Nairobi, Kenya; International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi, Kenya
| | - R A Skilton
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi, Kenya
| | - N Githaka
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi, Kenya.
| | - H Kiara
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi, Kenya
| | - E Kabiru
- Department of Zoological Sciences, Kenyatta University, P.O. Box 43844, Nairobi, Kenya
| | - T Shah
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi, Kenya
| | - A J Musoke
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi, Kenya
| | - R P Bishop
- International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi, Kenya
| |
Collapse
|
23
|
Characteristics of Listeria monocytogenes isolated from tonsils of slaughtered fattening pigs in Switzerland. J Verbrauch Lebensm 2016. [DOI: 10.1007/s00003-015-0974-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
24
|
Wu S, Wu Q, Zhang J, Chen M, Guo W. Analysis of Multilocus Sequence Typing and Virulence Characterization of Listeria monocytogenes Isolates from Chinese Retail Ready-to-Eat Food. Front Microbiol 2016; 7:168. [PMID: 26909076 PMCID: PMC4754575 DOI: 10.3389/fmicb.2016.00168] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2015] [Accepted: 02/01/2016] [Indexed: 11/13/2022] Open
Abstract
Eighty Listeria monocytogenes isolates were obtained from Chinese retail ready-to-eat (RTE) food and were previously characterized with serotyping and antibiotic susceptibility tests. The aim of this study was to characterize the subtype and virulence potential of these L. monocytogenes isolates by multilocus sequence typing (MLST), virulence-associate genes, epidemic clones (ECs), and sequence analysis of the important virulence factor: internalin A (inlA). The result of MLST revealed that these L. monocytogenes isolates belonged to 14 different sequence types (STs). With the exception of four new STs (ST804, ST805, ST806, and ST807), all other STs observed in this study have been associated with human listeriosis and outbreaks to varying extents. Six virulence-associate genes (inlA, inlB, inlC, inlJ, hly, and llsX) were selected and their presence was investigated using PCR. All strains carried inlA, inlB, inlC, inlJ, and hly, whereas 38.8% (31/80) of strains harbored the listeriolysin S genes (llsX). A multiplex PCR assay was used to evaluate the presence of markers specific to epidemic clones of L. monocytogenes and identified 26.3% (21/80) of ECI in the 4b-4d-4e strains. Further study of inlA sequencing revealed that most strains contained the full-length InlA required for host cell invasion, whereas three mutations lead to premature stop codons (PMSC) within a novel PMSCs at position 326 (GAA → TAA). MLST and inlA sequence analysis results were concordant, and different virulence potentials within isolates were observed. These findings suggest that L. monocytogenes isolates from RTE food in China could be virulent and be capable of causing human illness. Furthermore, the STs and virulence profiles of L. monocytogenes isolates have significant implications for epidemiological and public health studies of this pathogen.
Collapse
Affiliation(s)
- Shi Wu
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied MicrobiologyGuangzhou, China
- School of Bioscience and Bioengineering, South China University of TechnologyGuangzhou, China
| | - Qingping Wu
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied MicrobiologyGuangzhou, China
| | - Jumei Zhang
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied MicrobiologyGuangzhou, China
| | - Moutong Chen
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied MicrobiologyGuangzhou, China
| | - Weipeng Guo
- Guangdong Institute of Microbiology, State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Open Laboratory of Applied MicrobiologyGuangzhou, China
| |
Collapse
|
25
|
The evolution and epidemiology of Listeria monocytogenes in Europe and the United States. INFECTION GENETICS AND EVOLUTION 2015; 35:172-83. [DOI: 10.1016/j.meegid.2015.08.008] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 08/03/2015] [Accepted: 08/04/2015] [Indexed: 11/20/2022]
|
26
|
Prevalence and distribution of Listeria monocytogenes inlA alleles prone to phase variation and inlA alleles with premature stop codon mutations among human, food, animal, and environmental isolates. Appl Environ Microbiol 2015; 81:8339-45. [PMID: 26407886 DOI: 10.1128/aem.02752-15] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 09/18/2015] [Indexed: 11/20/2022] Open
Abstract
In Listeria monocytogenes, 18 mutations leading to premature stop codons (PMSCs) in the virulence gene inlA have been identified to date. While most of these mutations represent nucleotide substitutions, a frameshift deletion in a 5' seven-adenine homopolymeric tract (HT) in inlA has also been reported. This HT may play a role in phase variation and was first identified among L. monocytogenes lineage II ribotype DUP-1039C isolates. In order to better understand the distribution of different inlA mutations in this ribotype, a newly developed multiplex real-time PCR assay was used to screen 368 DUP-1039C isolates from human, animal, and food-associated sources for three known 5' inlA HT alleles: (i) wild-type (WT) (A7), (ii) frameshift (FS) (A6), and (iii) guanine interruption (A2GA4) alleles. Additionally, 228 DUP-1039C isolates were screened for all inlA PMSCs; data on the presence of all inlA PMSCs for the other 140 isolates were obtained from previous studies. The statistical analysis based on 191 epidemiologically unrelated strains showed that strains with inlA PMSC mutations (n = 41) were overrepresented among food-associated isolates, while strains encoding full-length InlA (n = 150) were overrepresented among isolates from farm animals and their environments. Furthermore, the A6 allele was overrepresented and the A7 allele was underrepresented among food isolates, while the A6 allele was underrepresented among farm and animal isolates. Our results indicate that genetic variation in inlA contributes to niche adaptation within the lineage II subtype DUP-1039C.
Collapse
|
27
|
Soni DK, Singh DV, Dubey SK. Pregnancy - associated human listeriosis: Virulence and genotypic analysis of Listeria monocytogenes from clinical samples. J Microbiol 2015; 53:653-60. [PMID: 26231373 DOI: 10.1007/s12275-015-5243-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/26/2015] [Accepted: 07/15/2015] [Indexed: 11/26/2022]
Abstract
Listeria monocytogenes, a life-threatening pathogen, poses severe risk during pregnancy, may cause abortion, fetal death or neonatal morbidity in terms of septicemia and meningitis. The present study aimed at characterizing L. monocytogenes isolated from pregnant women based on serotyping, antibiotic susceptibility, virulence genes, in vivo pathogenicity test and ERIC- and REP-PCR fingerprint analyses. The results revealed that out of 3700 human clinical samples, a total of 30 (0.81%) isolates [12 (0.80%) from placental bit (1500), 18 (0.81%) from vaginal swab (2200)] were positive for L. monocytogenes. All the isolates belonged to serogroup 4b, and were + ve for virulence genes tested i.e. inlA, inlC, inlJ, plcA, prfA, actA, hlyA, and iap. Based on the mice inoculation tests, 20 isolates showed 100% and 4 isolates 60% relative virulence while 6 isolates were non-pathogenic. Moreover, 2 and 10 isolates were resistant to ciprofloxacin and cefoxitin, respectively, while the rest susceptible to other antibiotics used in this study. ERIC- and REP-PCR collectively depicted that the isolates from placental bit and vaginal swab had distinct PCR fingerprints except a few isolates with identical patterns. This study demonstrates prevalence of pathogenic strains mostly resistant to cefoxitin and/or ciprofloxacin. The results indicate the importance of isolating and characterizing the pathogen from human clinical samples as the pre-requisite for accurate epidemiological investigations.
Collapse
Affiliation(s)
- Dharmendra Kumar Soni
- Environmental Microbiology Laboratory, Department of Botany, Banaras Hindu University, Varanasi, 221005, India
| | | | | |
Collapse
|
28
|
Jamali H, Paydar M, Ismail S, Looi CY, Wong WF, Radmehr B, Abedini A. Prevalence, antimicrobial susceptibility and virulotyping of Listeria species and Listeria monocytogenes isolated from open-air fish markets. BMC Microbiol 2015. [PMID: 26209099 DOI: 10.1186/s12866‐015‐0476‐7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND The aim of this study was to investigate the prevalence and characterization of Listeria species and Listeria monocytogenes isolated from raw fish and open-air fish market environments. Eight hundred and sixty two samples including raw fish and fish market environments (samples from workers' hands, workers' knives, containers and work surface) were collected from the open-air fish markets in the Northern region of Iran. RESULTS Listeria spp. was isolated from 104/488 (21.3%) raw fish and 29/374 (7.8%) of samples from open-air fish market environment. The isolates of Listeria spp. included L. innocua (35.3%), L. monocytogenes (32.3%), L. seeligeri (18%), and L. ivanovii (14.3%). Of the 43 L. monocytogenes isolates, 31 (72.1%), 10 (23.3%) and 2 (4.7%) belonged to serovars 1/2a, 4b, and 1/2b, respectively. The inlA, inlB, inlC, inlJ, actA, hlyA, iap, plcA, and prfA virulence-associated genes were detected in almost all of the L. monocytogenes isolates. The Listeria spp. isolates showed high resistance against tetracycline (23.3%), penicillin G, and cephalothin (each 16.5%). Besides, we observed significant resistance level to tetracycline (27.9%), ampicillin (20.9%), cephalothin, penicillin G, and streptomycin (each 16.3%) in the L. monocytogenes isolates. All of the isolates were susceptible to cefotaxime, gentamicin, kanamycin, and pefloxacin. We found that tetM (25.6%), tetA (23.3%), ampC (14%), and penA (11.6%) were the most prevalent antibiotic resistance genes in the L. monocytogenes isolates. CONCLUSIONS Recovery of potentially pathogenic L. monocytogenes from raw fish and environment of open-air fish market samples in this study is a convincing evidence for the zoonotic potential of listeriosis.
Collapse
Affiliation(s)
- Hossein Jamali
- Biohealth Science Program, Institute of Biological Science, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Mohammadjavad Paydar
- Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Salmah Ismail
- Biohealth Science Program, Institute of Biological Science, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Chung Yeng Looi
- Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Won Fen Wong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Behrad Radmehr
- Department of Food Hygiene and Quality Control, Islamic Azad University-Karaj Branch, Karaj, 31485-313, Iran.
| | - Atefeh Abedini
- Centre de Recherche en Reproduction Animale, Université de Montréal, C.P. 5000, St-Hyacinthe, QC, Canada.
| |
Collapse
|
29
|
Jamali H, Paydar M, Ismail S, Looi CY, Wong WF, Radmehr B, Abedini A. Prevalence, antimicrobial susceptibility and virulotyping of Listeria species and Listeria monocytogenes isolated from open-air fish markets. BMC Microbiol 2015; 15:144. [PMID: 26209099 PMCID: PMC4515007 DOI: 10.1186/s12866-015-0476-7] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2014] [Accepted: 07/03/2015] [Indexed: 12/03/2022] Open
Abstract
BACKGROUND The aim of this study was to investigate the prevalence and characterization of Listeria species and Listeria monocytogenes isolated from raw fish and open-air fish market environments. Eight hundred and sixty two samples including raw fish and fish market environments (samples from workers' hands, workers' knives, containers and work surface) were collected from the open-air fish markets in the Northern region of Iran. RESULTS Listeria spp. was isolated from 104/488 (21.3%) raw fish and 29/374 (7.8%) of samples from open-air fish market environment. The isolates of Listeria spp. included L. innocua (35.3%), L. monocytogenes (32.3%), L. seeligeri (18%), and L. ivanovii (14.3%). Of the 43 L. monocytogenes isolates, 31 (72.1%), 10 (23.3%) and 2 (4.7%) belonged to serovars 1/2a, 4b, and 1/2b, respectively. The inlA, inlB, inlC, inlJ, actA, hlyA, iap, plcA, and prfA virulence-associated genes were detected in almost all of the L. monocytogenes isolates. The Listeria spp. isolates showed high resistance against tetracycline (23.3%), penicillin G, and cephalothin (each 16.5%). Besides, we observed significant resistance level to tetracycline (27.9%), ampicillin (20.9%), cephalothin, penicillin G, and streptomycin (each 16.3%) in the L. monocytogenes isolates. All of the isolates were susceptible to cefotaxime, gentamicin, kanamycin, and pefloxacin. We found that tetM (25.6%), tetA (23.3%), ampC (14%), and penA (11.6%) were the most prevalent antibiotic resistance genes in the L. monocytogenes isolates. CONCLUSIONS Recovery of potentially pathogenic L. monocytogenes from raw fish and environment of open-air fish market samples in this study is a convincing evidence for the zoonotic potential of listeriosis.
Collapse
Affiliation(s)
- Hossein Jamali
- Biohealth Science Program, Institute of Biological Science, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Mohammadjavad Paydar
- Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Salmah Ismail
- Biohealth Science Program, Institute of Biological Science, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Chung Yeng Looi
- Department of Pharmacology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Won Fen Wong
- Department of Medical Microbiology, Faculty of Medicine, University of Malaya, 50603, Kuala Lumpur, Malaysia.
| | - Behrad Radmehr
- Department of Food Hygiene and Quality Control, Islamic Azad University-Karaj Branch, Karaj, 31485-313, Iran.
| | - Atefeh Abedini
- Centre de Recherche en Reproduction Animale, Université de Montréal, C.P. 5000, St-Hyacinthe, QC, Canada.
| |
Collapse
|
30
|
Genotypic characterization and antimicrobial resistance of Listeria monocytogenes from ready-to-eat foods. Food Control 2014. [DOI: 10.1016/j.foodcont.2014.03.038] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
31
|
Althaus D, Lehner A, Brisse S, Maury M, Tasara T, Stephan R. Characterization of Listeria monocytogenes strains isolated during 2011-2013 from human infections in Switzerland. Foodborne Pathog Dis 2014; 11:753-8. [PMID: 25007293 DOI: 10.1089/fpd.2014.1747] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Listeria monocytogenes, an emerging foodborne pathogen, can cause in the population at risk severe infections that are associated with high case fatality rates. A total of 93 L. monocytogenes strains isolated from different patients in Switzerland from July 2011 to September 2013 were further characterized. Septicemia was reported for 74.2% of the patients, meningitis for 10.8%, and abortion for 3.2%. The majority of the strains belonged to serotype 1/2a (n=58) followed by serotype 4b (n=28), 1/2b (n=5), and 1/2c (n=2). The strains represented 35 multilocus sequence typing sequence types, 8 of which were designated for the first time. Sequence analysis of the inlA gene in the 35 sequence types showed that most of the strains encoded full-length proteins. Screening for Listeriolysin S showed the presence of this virulence factor in 29 of the 33 genetic lineage I strains. By using ApaI and AscI for pulsed-field gel electrophoresis, most strains showed distinguishable patterns.
Collapse
Affiliation(s)
- Denise Althaus
- 1 Institute for Food Safety and Hygiene, Vetsuisse Faculty, University of Zurich , Zurich, Switzerland
| | | | | | | | | | | |
Collapse
|
32
|
Morgan CC, Mc Cartney AM, Donoghue MTA, Loughran NB, Spillane C, Teeling EC, O'Connell MJ. Molecular adaptation of telomere associated genes in mammals. BMC Evol Biol 2013; 13:251. [PMID: 24237966 PMCID: PMC3833184 DOI: 10.1186/1471-2148-13-251] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Accepted: 11/06/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Placental mammals display a huge range of life history traits, including size, longevity, metabolic rate and germ line generation time. Although a number of general trends have been proposed between these traits, there are exceptions that warrant further investigation. Species such as naked mole rat, human and certain bat species all exhibit extreme longevity with respect to body size. It has long been established that telomeres and telomere maintenance have a clear role in ageing but it has not yet been established whether there is evidence for adaptation in telomere maintenance proteins that could account for increased longevity in these species. RESULTS Here we carry out a molecular investigation of selective pressure variation, specifically focusing on telomere associated genes across placental mammals. In general we observe a large number of instances of positive selection acting on telomere genes. Although these signatures of selection overall are not significantly correlated with either longevity or body size we do identify positive selection in the microbat species Myotis lucifugus in functionally important regions of the telomere maintenance genes DKC1 and TERT, and in naked mole rat in the DNA repair gene BRCA1. CONCLUSION These results demonstrate the multifarious selective pressures acting across the mammal phylogeny driving lineage-specific adaptations of telomere associated genes. Our results show that regardless of the longevity of a species, these proteins have evolved under positive selection thereby removing increased longevity as the single selective force driving this rapid rate of evolution. However, evidence of molecular adaptations specific to naked mole rat and Myotis lucifugus highlight functionally significant regions in genes that may alter the way in which telomeres are regulated and maintained in these longer-lived species.
Collapse
|
33
|
Jamali H, Radmehr B, Thong KL. Prevalence, characterisation, and antimicrobial resistance of Listeria species and Listeria monocytogenes isolates from raw milk in farm bulk tanks. Food Control 2013. [DOI: 10.1016/j.foodcont.2013.04.023] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
34
|
Shen J, Rump L, Zhang Y, Chen Y, Wang X, Meng J. Molecular subtyping and virulence gene analysis of Listeria monocytogenes isolates from food. Food Microbiol 2013; 35:58-64. [PMID: 23628615 DOI: 10.1016/j.fm.2013.02.014] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 02/03/2013] [Accepted: 02/26/2013] [Indexed: 11/18/2022]
Abstract
A total of 67 Listeria monocytogenes isolates from 698 raw meat samples were characterized for molecular serogroup identification and antimicrobial susceptibility. Approximately one third (32.8%) of the isolates belonged to molecular serogroup 1/2a, 3a, followed by 1/2c, 3c (26.9%), 1/2b, 3b, 7 (22.4%), 4b, 4d, 4e (16.4%) and 4a, 4c (1.5%). Most of the L. monocytogenes isolates were susceptible to 14 antimicrobials tested but several were resistant to tetracycline, ciprofloxacin and nitrofurantoin. An additional 30 L. monocytogenes isolates from chicken and produce in our collection were also included to determine the presence of significant virulence markers. All 97 isolates carried inlC and inlJ except for a lineage III isolate 110-1. Most Listeriolysin S (LLS)-carrying isolates (11/12) belonged to lineage I, whereas the remaining one isolate belonged to lineage III. Five 4b, 4d, 4e isolates including two from turkey and three from produce belonged to Epidemic Clone I (ECI). Four molecular serogroup associated mutation types that lead to premature stop codons (PMSCs) in inlA were identified. PFGE and inlA sequence analysis results were concordant, and different virulence potential within 1/2a, 3a and 4b, 4d, 4e isolates were observed. The study revealed that a subset of isolates from meat and produce belonged to ECI, harbored inlC, inlJ and LLS, and produced full length InlA, suggesting that they be capable of causing human illness.
Collapse
Affiliation(s)
- Jinling Shen
- College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi Province 712100, China
| | | | | | | | | | | |
Collapse
|
35
|
Examination of food chain-derived Listeria monocytogenes strains of different serotypes reveals considerable diversity in inlA genotypes, mutability, and adaptation to cold temperatures. Appl Environ Microbiol 2013; 79:1915-22. [PMID: 23315746 DOI: 10.1128/aem.03341-12] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Listeria monocytogenes strains belonging to serotypes 1/2a and 4b are frequently linked to listeriosis. While inlA mutations leading to premature stop codons (PMSCs) and attenuated virulence are common in 1/2a, they are rare in serotype 4b. We observed PMSCs in 35% of L. monocytogenes isolates (n = 54) recovered from the British Columbia food supply, including serotypes 1/2a (30%), 1/2c (100%), and 3a (100%), and a 3-codon deletion (amino acid positions 738 to 740) seen in 57% of 4b isolates from fish-processing facilities. Caco-2 invasion assays showed that two isolates with the deletion were significantly more invasive than EGD-SmR (P < 0.0001) and were either as (FF19-1) or more (FE13-1) invasive than a clinical control strain (08-5578) (P = 0.006). To examine whether serotype 1/2a was more likely to acquire mutations than other serotypes, strains were plated on agar with rifampin, revealing 4b isolates to be significantly more mutable than 1/2a, 1/2c, and 3a serotypes (P = 0.0002). We also examined the ability of 33 strains to adapt to cold temperature following a downshift from 37°C to 4°C. Overall, three distinct cold-adapting groups (CAG) were observed: 46% were fast (<70 h), 39% were intermediate (70 to 200 h), and 15% were slow (>200 h) adaptors. Intermediate CAG strains (70%) more frequently possessed inlA PMSCs than did fast (20%) and slow (10%) CAGs; in contrast, 87% of fast adaptors lacked inlA PMSCs. In conclusion, we report food chain-derived 1/2a and 4b serotypes with a 3-codon deletion possessing invasive behavior and the novel association of inlA genotypes encoding a full-length InlA with fast cold-adaptation phenotypes.
Collapse
|
36
|
Garzón-Ospina D, López C, Forero-Rodríguez J, Patarroyo MA. Genetic diversity and selection in three Plasmodium vivax merozoite surface protein 7 (Pvmsp-7) genes in a Colombian population. PLoS One 2012; 7:e45962. [PMID: 23049905 PMCID: PMC3458108 DOI: 10.1371/journal.pone.0045962] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 08/28/2012] [Indexed: 11/18/2022] Open
Abstract
A completely effective vaccine for malaria (one of the major infectious diseases worldwide) is not yet available; different membrane proteins involved in parasite-host interactions have been proposed as candidates for designing it. It has been found that proteins encoded by the merozoite surface protein (msp)-7 multigene family are antibody targets in natural infection; the nucleotide diversity of three Pvmsp-7 genes was thus analyzed in a Colombian parasite population. By contrast with P. falciparum msp-7 loci and ancestral P. vivax msp-7 genes, specie-specific duplicates of the latter specie display high genetic variability, generated by single nucleotide polymorphisms, repeat regions, and recombination. At least three major allele types are present in Pvmsp-7C, Pvmsp-7H and Pvmsp-7I and positive selection seems to be operating on the central region of these msp-7 genes. Although this region has high genetic polymorphism, the C-terminus (Pfam domain ID: PF12948) is conserved and could be an important candidate when designing a subunit-based antimalarial vaccine.
Collapse
Affiliation(s)
- Diego Garzón-Ospina
- Fundación Instituto de Inmunología de Colombia – FIDIC, Bogotá DC, Colombia
- Microbiology postgraduate program, Universidad Nacional de Colombia, Bogotá DC, Colombia
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá DC, Colombia
| | - Carolina López
- Fundación Instituto de Inmunología de Colombia – FIDIC, Bogotá DC, Colombia
- Microbiology postgraduate program, Universidad Nacional de Colombia, Bogotá DC, Colombia
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá DC, Colombia
| | | | - Manuel A. Patarroyo
- Fundación Instituto de Inmunología de Colombia – FIDIC, Bogotá DC, Colombia
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá DC, Colombia
- * E-mail:
| |
Collapse
|
37
|
Pagadala S, Parveen S, Rippen T, Luchansky JB, Call JE, Tamplin ML, Porto-Fett ACS. Prevalence, characterization and sources of Listeria monocytogenes in blue crab (Callinectus sapidus) meat and blue crab processing plants. Food Microbiol 2012; 31:263-70. [PMID: 22608232 DOI: 10.1016/j.fm.2012.03.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 03/28/2012] [Accepted: 03/29/2012] [Indexed: 12/11/2022]
Abstract
Seven blue crab processing plants were sampled to determine the prevalence and sources of Listeria spp. and Listeria monocytogenes for two years (2006-2007). A total of 488 raw crabs, 624 cooked crab meat (crab meat) and 624 environmental samples were tested by standard methods. Presumptive Listeria spp. were isolated from 19.5% of raw crabs, 10.8% of crab meat, and 69.5% of environmental samples. L. monocytogenes was isolated from 4.5% of raw crabs, 0.2% of crab meat, and 2.1% of environmental samples. Ninety-seven percent of the isolates were resistant to at least one of the ten antibiotics tested. Eight different serotypes were found among 76 L. monocytogenes isolates tested with the most common being 4b, 1/2b and 1/2a. Automated EcoRI ribotyping differentiated 11 ribotypes among the 106 L. monocytogenes isolates. Based on ribotyping analysis, the distribution of the ribotypes in each processing plant had a unique contamination pattern. A total of 92 ApaI and 88 AscI pulsotypes among the 106 L. monocytogenes isolates were found and distinct pulsotypes were observed in raw crab, crab meat and environmental samples. Ribotypes and serotypes recovered from crab processing plants included subtypes that have been associated with listeriosis cases in other food outbreaks. Our findings suggest that molecular methods may provide critical information about sources of L. monocytogenes in crab processing plants and will augment efforts to improve food safety control strategies such as targeting specific sources of contamination and use of aggressive detergents prior to sanitizing.
Collapse
Affiliation(s)
- Sivaranjani Pagadala
- Food Science and Technology Ph.D. Program, Department of Agriculture, Food and Resource Sciences, University of Maryland Eastern Shore, 2116 Center for Food Science and Technology, Princess Anne, MD 21853, USA
| | | | | | | | | | | | | |
Collapse
|
38
|
Kovačević J, Mesak LR, Allen KJ. Occurrence and characterization of Listeria spp. in ready-to-eat retail foods from Vancouver, British Columbia. Food Microbiol 2012; 30:372-8. [DOI: 10.1016/j.fm.2011.12.015] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 12/15/2011] [Indexed: 12/21/2022]
|
39
|
Sant'Ana AS, Igarashi MC, Landgraf M, Destro MT, Franco BD. Prevalence, populations and pheno- and genotypic characteristics of Listeria monocytogenes isolated from ready-to-eat vegetables marketed in São Paulo, Brazil. Int J Food Microbiol 2012; 155:1-9. [DOI: 10.1016/j.ijfoodmicro.2011.12.036] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Revised: 12/18/2011] [Accepted: 12/19/2011] [Indexed: 10/14/2022]
|
40
|
Tsai YHL, Maron SB, McGann P, Nightingale KK, Wiedmann M, Orsi RH. Recombination and positive selection contributed to the evolution of Listeria monocytogenes lineages III and IV, two distinct and well supported uncommon L. monocytogenes lineages. INFECTION GENETICS AND EVOLUTION 2011; 11:1881-90. [PMID: 21854875 DOI: 10.1016/j.meegid.2011.08.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2011] [Revised: 08/03/2011] [Accepted: 08/04/2011] [Indexed: 10/17/2022]
Abstract
Listeriamonocytogenes lineages III and IV represent two uncommon lineages of the human and animal pathogen L. monocytogenes, characterized by occurrence of unusual phenotypic and genetic characteristics that differentiate them from the common lineages I and II. To gain further insights into the evolution of lineages III and IV, we amplified and sequenced housekeeping genes (i.e., gap, prs, purM, ribC, and sigB), internalin genes (i.e., inlA, inlB, inlC, inlG, inlC2, inlD, inlE, inlF, and inlH) and the virulence gene cluster containing prfA, plcA, hly, mpl, actA, and plcB for lineages III (n = 7) and IV (n = 4) isolates. Phylogenetic analyses of the sequences obtained along with previously reported sequence data for 40 isolates representing lineages I (n = 18), II (n = 21), and III (n = 1), showed that lineages III and IV represent divergent and monophyletic lineages. The virulence gene cluster as well as the inlAB operon were present in all isolates, with inlF absent from all lineages III and IV isolates. While all lineage IV isolates contained only inlC (in addition to inlAB), lineage III isolates showed considerable diversity with regard to internalin gene presence, including presence of (i) only inlC (n = 2), (ii) inlC and inlGC2DE (n = 3), (iii) only inlGC2DE (n = 2), and (iv) inlC and inlC2DE (n = 1). In addition to evidence for horizontal gene transfer events, among lineages III and IV isolates, in prs, actA, plcB, mpl, inlA, inlB, inlG, inlD, and inlE, we also found significant evidence for positive selection in the hly promoter region and, along the lineages III and IV branches, for actA (including in sites recognized for interactions with proteins involved in actin tail polymerization). In conclusion, lineages III and IV represent two distinct monophyletic groups with contributions of intragenic recombination to the evolution of their internalin genes as well as contributions of positive selection to evolution of the virulence genes island.
Collapse
|
41
|
Joseph SJ, Didelot X, Gandhi K, Dean D, Read TD. Interplay of recombination and selection in the genomes of Chlamydia trachomatis. Biol Direct 2011; 6:28. [PMID: 21615910 PMCID: PMC3126793 DOI: 10.1186/1745-6150-6-28] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2011] [Accepted: 05/26/2011] [Indexed: 02/02/2023] Open
Abstract
Background Chlamydia trachomatis is an obligate intracellular bacterial parasite, which causes several severe and debilitating diseases in humans. This study uses comparative genomic analyses of 12 complete published C. trachomatis genomes to assess the contribution of recombination and selection in this pathogen and to understand the major evolutionary forces acting on the genome of this bacterium. Results The conserved core genes of C. trachomatis are a large proportion of the pan-genome: we identified 836 core genes in C. trachomatis out of a range of 874-927 total genes in each genome. The ratio of recombination events compared to mutation (ρ/θ) was 0.07 based on ancestral reconstructions using the ClonalFrame tool, but recombination had a significant effect on genetic diversification (r/m = 0.71). The distance-dependent decay of linkage disequilibrium also indicated that C. trachomatis populations behaved intermediately between sexual and clonal extremes. Fifty-five genes were identified as having a history of recombination and 92 were under positive selection based on statistical tests. Twenty-three genes showed evidence of being under both positive selection and recombination, which included genes with a known role in virulence and pathogencity (e.g., ompA, pmps, tarp). Analysis of inter-clade recombination flux indicated non-uniform currents of recombination between clades, which suggests the possibility of spatial population structure in C. trachomatis infections. Conclusions C. trachomatis is the archetype of a bacterial species where recombination is relatively frequent yet gene gains by horizontal gene transfer (HGT) and losses (by deletion) are rare. Gene conversion occurs at sites across the whole C. trachomatis genome but may be more often fixed in genes that are under diversifying selection. Furthermore, genome sequencing will reveal patterns of serotype specific gene exchange and selection that will generate important research questions for understanding C. trachomatis pathogenesis. Reviewers This article was reviewed by Dr. Jeremy Selengut, Dr. Lee S. Katz (nominated by Dr. I. King Jordan) and Dr. Arcady Mushegian.
Collapse
Affiliation(s)
- Sandeep J Joseph
- Department of Medicine, Division of Infectious, Diseases Emory University School of Medicine, 615 Michael Street, Atlanta, GA 30322, USA
| | | | | | | | | |
Collapse
|
42
|
Van Stelten A, Simpson JM, Chen Y, Scott VN, Whiting RC, Ross WH, Nightingale KK. Significant shift in median guinea pig infectious dose shown by an outbreak-associated Listeria monocytogenes epidemic clone strain and a strain carrying a premature stop codon mutation in inlA. Appl Environ Microbiol 2011; 77:2479-87. [PMID: 21296943 PMCID: PMC3067448 DOI: 10.1128/aem.02626-10] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Accepted: 01/28/2011] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes contains (i) epidemic clone (EC) strains, which have been linked to the majority of listeriosis outbreaks worldwide and are overrepresented among sporadic cases in the United States, and (ii) strains commonly isolated from ready-to-eat foods that carry a mutation leading to a premature stop codon (PMSC) in inlA, which encodes the key virulence factor internalin A (InlA). Internalin A binds certain isoforms of the cellular receptor E-cadherin to facilitate crossing the intestinal barrier during the initial stages of an L. monocytogenes infection. Juvenile guinea pigs, which express the human isoform of E-cadherin that binds InlA, were intragastrically challenged with a range of doses of (i) an EC strain associated with a listeriosis outbreak or (ii) a strain carrying a PMSC mutation in inlA. Recovery of L. monocytogenes from tissues (i.e., liver, spleen, mesenteric lymph nodes, and ileum) was used to develop strain-specific dose-response curves on the basis of individual and combined organ data. Modeling of individual and combined organ data revealed an approximate 1.2 to 1.3 log(10) increase in the median infectious dose for the strain carrying a PMSC in inlA relative to that for the EC strain. Inclusion of the strain parameter significantly improved the goodness of fit for individual and combined organ models, indicating a significant shift in median infectious dose for guinea pigs challenged with an inlA PMSC strain compared to that for guinea pigs challenged with an EC strain. Results from this work provide evidence that the L. monocytogenes dose-response relationship is strain specific and will provide critical data for enhancement of current risk assessments and development of future risk assessments.
Collapse
Affiliation(s)
- A. Van Stelten
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523, Grocery Manufacturers Association, Washington, DC 20005, United States Food and Drug Administration, College Park, Maryland 20740, Exponent, Bowie, Maryland 20715, Health Canada, Ottawa, Ontario K1A OJ0, Canada
| | - J. M. Simpson
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523, Grocery Manufacturers Association, Washington, DC 20005, United States Food and Drug Administration, College Park, Maryland 20740, Exponent, Bowie, Maryland 20715, Health Canada, Ottawa, Ontario K1A OJ0, Canada
| | - Y. Chen
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523, Grocery Manufacturers Association, Washington, DC 20005, United States Food and Drug Administration, College Park, Maryland 20740, Exponent, Bowie, Maryland 20715, Health Canada, Ottawa, Ontario K1A OJ0, Canada
| | - V. N. Scott
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523, Grocery Manufacturers Association, Washington, DC 20005, United States Food and Drug Administration, College Park, Maryland 20740, Exponent, Bowie, Maryland 20715, Health Canada, Ottawa, Ontario K1A OJ0, Canada
| | - R. C. Whiting
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523, Grocery Manufacturers Association, Washington, DC 20005, United States Food and Drug Administration, College Park, Maryland 20740, Exponent, Bowie, Maryland 20715, Health Canada, Ottawa, Ontario K1A OJ0, Canada
| | - W. H. Ross
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523, Grocery Manufacturers Association, Washington, DC 20005, United States Food and Drug Administration, College Park, Maryland 20740, Exponent, Bowie, Maryland 20715, Health Canada, Ottawa, Ontario K1A OJ0, Canada
| | - K. K. Nightingale
- Department of Animal Sciences, Colorado State University, Fort Collins, Colorado 80523, Grocery Manufacturers Association, Washington, DC 20005, United States Food and Drug Administration, College Park, Maryland 20740, Exponent, Bowie, Maryland 20715, Health Canada, Ottawa, Ontario K1A OJ0, Canada
| |
Collapse
|
43
|
Diverse geno- and phenotypes of persistent Listeria monocytogenes isolates from fermented meat sausage production facilities in Portugal. Appl Environ Microbiol 2011; 77:2701-15. [PMID: 21378045 DOI: 10.1128/aem.02553-10] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The persistence of Listeria monocytogenes in food-associated environments represents a key factor in transmission of this pathogen. To identify persistent and transient strains associated with production of fermented meat sausages in northern Portugal, 1,723 L. monocytogenes isolates from raw material and finished products from 11 processors were initially characterized by random amplification of polymorphic DNA (RAPD), PCR-based molecular serotyping, and epidemic clone characterization, as well as cadmium, arsenic, and tetracycline resistance typing. Pulsed-field gel electrophoresis (PFGE) typing of 240 representative isolates provided evidence for persistence of L. monocytogenes for periods of time ranging from 10 to 32 months for all seven processors for which isolates from different production dates were available. Among 50 L. monocytogenes isolates that included one representative for each PFGE pattern obtained from a given sample, 12 isolates showed reduced invasion efficiency in Caco-2 cells, including 8 isolates with premature stop codons in inlA. Among 41 isolates representing sporadic and persistent PFGE types, 22 isolates represented lysogens. Neither strains with reduced invasion nor lysogens were overrepresented among persistent isolates. While the susceptibility of isolates to lysogenic phages also did not correlate with persistence, it appeared to be associated with molecular serotype. Our data show the following. (i) RAPD may not be suitable for analysis of large sets of L. monocytogenes isolates. (ii) While a large diversity of L. monocytogenes subtypes is found in Portuguese fermented meat sausages, persistence of L. monocytogenes in this food chain is common. (iii) Persistent L. monocytogenes strains are diverse and do not appear to be characterized by unique genetic or phenotypic characteristics.
Collapse
|
44
|
Larsen MH, Koch AG, Ingmer H. Listeria monocytogenes efficiently invades Caco-2 cells after low-temperature storage in broth and on deli meat. Foodborne Pathog Dis 2010; 7:1013-8. [PMID: 20443727 DOI: 10.1089/fpd.2009.0470] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
The objective of this study was to investigate how various growth conditions influence the virulence of Listeria monocytogenes monitored by its ability to invade the epithelial cell lines Caco-2 and INT-407. The growth conditions examined were modified atmosphere-packaged deli meat and brain heart infusion broth (BHI) with and without salt. Five strains of L. monocytogenes were selected to investigate their invasiveness and all strains invaded Caco-2 cells at higher levels than INT-407 cells. Further, the clinical strains (3443 and 3734) were more invasive (p < 0.05) than the strains isolated from meat and food-processing environments (3008, 3126, and 4140) after grown in BHI at 30 degrees C. This attenuation could not be ascribed to a defective Internalin A as all strains encoded an intact inlA gene. To determine the influence of food products on virulence, the ability of L. monocytogenes to invade Caco-2 cells was compared after growth on a fermented sausage and on cured cooked ham to that of bacteria grown in BHI broth supplemented with salt. Samples were stored under chilling conditions for up to 4 weeks. The results showed no difference (p > 0.05) in invasiveness after 7 days at 10 degrees C in BHI broth or on sausage, whereas a slight increase (p < 0.05) was observed after incubation on ham for 2 and 4 weeks compared to that in BHI broth. Most importantly, our results show that L. monocytogenes efficiently invade Caco-2 cells even after 4 weeks of storage at chilled temperature. This is highly relevant for safety assessment of this organism in food as these conditions reflect storage of ready-to-eat food products in domestic refrigerators.
Collapse
Affiliation(s)
- Marianne Halberg Larsen
- Department of Veterinary Disease Biology, Centre for Advanced Food Studies, Faculty of Life Sciences, University of Copenhagen, Frederiksberg C, Denmark.
| | | | | |
Collapse
|
45
|
Monk IR, Casey PG, Hill C, Gahan CGM. Directed evolution and targeted mutagenesis to murinize Listeria monocytogenes internalin A for enhanced infectivity in the murine oral infection model. BMC Microbiol 2010; 10:318. [PMID: 21144051 PMCID: PMC3016325 DOI: 10.1186/1471-2180-10-318] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2010] [Accepted: 12/13/2010] [Indexed: 01/30/2023] Open
Abstract
BACKGROUND Internalin A (InlA) is a critical virulence factor which mediates the initiation of Listeria monocytogenes infection by the oral route in permissive hosts. The interaction of InlA with the host cell ligand E-cadherin efficiently stimulates L. monocytogenes entry into human enterocytes, but has only a limited interaction with murine cells. RESULTS We have created a surface display library of randomly mutated InlA in a non-invasive heterologous host Lactococcus lactis in order to create and screen novel variants of this invasion factor. After sequential passage through a murine cell line (CT-26), multiple clones with enhanced invasion characteristics were identified. Competitive index experiments were conducted in mice using selected mutations introduced into L. monocytogenes EGD-e background. A novel single amino acid change was identified which enhanced virulence by the oral route in the murine model and will form the basis of further engineering approaches. As a control a previously described EGD-InlA(m) murinized strain was also re-created as part of this study with minor modifications and designated EGD-e InlA(m)*. The strain was created using a procedure that minimizes the likelihood of secondary mutations and incorporates Listeria-optimized codons encoding the altered amino acids. L. monocytogenes EGD-e InlA(m)* yielded consistently higher level murine infections by the oral route when compared to EGD-e, but did not display the two-fold increased invasion into a human cell line that was previously described for the EGD-InlA(m) strain. CONCLUSIONS We have used both site-directed mutagenesis and directed evolution to create variants of InlA which may inform future structure-function analyses of this protein. During the course of the study we engineered a murinized strain of L. monocytogenes EGD-e which shows reproducibly higher infectivity in the intragastric murine infection model than the wild type, but does not display enhanced entry into human cells as previously observed. This murinized L. monocytogenes strain will provide a useful tool for the analysis of the gastrointestinal phase of listeriosis.
Collapse
Affiliation(s)
- Ian R Monk
- Alimentary Pharmabiotic Centre & Department of Microbiology, University College Cork, Western Road, Cork, Ireland
| | | | | | | |
Collapse
|
46
|
Deng X, Phillippy AM, Li Z, Salzberg SL, Zhang W. Probing the pan-genome of Listeria monocytogenes: new insights into intraspecific niche expansion and genomic diversification. BMC Genomics 2010; 11:500. [PMID: 20846431 PMCID: PMC2996996 DOI: 10.1186/1471-2164-11-500] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 09/16/2010] [Indexed: 11/25/2022] Open
Abstract
Background Bacterial pathogens often show significant intraspecific variations in ecological fitness, host preference and pathogenic potential to cause infectious disease. The species of Listeria monocytogenes, a facultative intracellular pathogen and the causative agent of human listeriosis, consists of at least three distinct genetic lineages. Two of these lineages predominantly cause human sporadic and epidemic infections, whereas the third lineage has never been implicated in human disease outbreaks despite its overall conservation of many known virulence factors. Results Here we compare the genomes of 26 L. monocytogenes strains representing the three lineages based on both in silico comparative genomic analysis and high-density, pan-genomic DNA array hybridizations. We uncover 86 genes and 8 small regulatory RNAs that likely make L. monocytogenes lineages differ in carbohydrate utilization and stress resistance during their residence in natural habitats and passage through the host gastrointestinal tract. We also identify 2,330 to 2,456 core genes that define this species along with an open pan-genome pool that contains more than 4,052 genes. Phylogenomic reconstructions based on 3,560 homologous groups allowed robust estimation of phylogenetic relatedness among L. monocytogenes strains. Conclusions Our pan-genome approach enables accurate co-analysis of DNA sequence and hybridization array data for both core gene estimation and phylogenomics. Application of our method to the pan-genome of L. monocytogenes sheds new insights into the intraspecific niche expansion and evolution of this important foodborne pathogen.
Collapse
Affiliation(s)
- Xiangyu Deng
- National Center for Food Safety and Technology, Illinois Institute of Technology, Summit, Illinois 60501, USA
| | | | | | | | | |
Collapse
|
47
|
A targeted multilocus genotyping assay for lineage, serogroup, and epidemic clone typing of Listeria monocytogenes. Appl Environ Microbiol 2010; 76:6680-4. [PMID: 20709839 DOI: 10.1128/aem.01008-10] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A 30-probe assay was developed for simultaneous classification of Listeria monocytogenes isolates by lineage (I to IV), major serogroup (4b, 1/2b, 1/2a, and 1/2c), and epidemic clone (EC) type (ECI, ECIa, ECII, and ECIII). The assay was designed to facilitate rapid strain characterization and the integration of subtype data into risk-based inspection programs.
Collapse
|
48
|
Revelation by single-nucleotide polymorphism genotyping that mutations leading to a premature stop codon in inlA are common among Listeria monocytogenes isolates from ready-to-eat foods but not human listeriosis cases. Appl Environ Microbiol 2010; 76:2783-90. [PMID: 20208021 DOI: 10.1128/aem.02651-09] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Listeria monocytogenes utilizes internalin A (InlA; encoded by inlA) to cross the intestinal barrier to establish a systemic infection. Multiple naturally occurring mutations leading to a premature stop codon (PMSC) in inlA have been reported worldwide, and these mutations are causally associated with attenuated virulence. Five inlA PMSC mutations recently discovered among isolates from France and the United States were included as additional markers in our previously described inlA single-nucleotide polymorphism (SNP) genotyping assay. This assay was used to screen >1,000 L. monocytogenes isolates from ready-to-eat (RTE) foods (n = 502) and human listeriosis cases (n = 507) for 18 inlA PMSC mutations. A significantly (P < 0.0001) greater proportion of RTE food isolates (45.0%) carried a PMSC mutation in inlA compared to human clinical isolates (5.1%). The proportion of L. monocytogenes with or without PMSC mutations in inlA was similar among isolates from different RTE food categories except for deli meats, which included a marginally higher proportion (P = 0.12) of isolates carrying a PMSC in inlA. We also analyzed the distribution of epidemic clone (EC) strains, which have been linked to the majority of listeriosis outbreaks worldwide and are overrepresented among sporadic cases in the United States. We observed a significant (P < 0.05) overrepresentation of EC strains in deli and seafood salads and a significant (P < 0.05) underrepresentation of EC strains in smoked seafood. These results provide important data to predict the human health risk of exposure to L. monocytogenes strains that differ in pathogenic potential through consumption of contaminated RTE foods.
Collapse
|
49
|
Gilmour MW, Graham M, Van Domselaar G, Tyler S, Kent H, Trout-Yakel KM, Larios O, Allen V, Lee B, Nadon C. High-throughput genome sequencing of two Listeria monocytogenes clinical isolates during a large foodborne outbreak. BMC Genomics 2010; 11:120. [PMID: 20167121 PMCID: PMC2834635 DOI: 10.1186/1471-2164-11-120] [Citation(s) in RCA: 234] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2009] [Accepted: 02/18/2010] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND A large, multi-province outbreak of listeriosis associated with ready-to-eat meat products contaminated with Listeria monocytogenes serotype 1/2a occurred in Canada in 2008. Subtyping of outbreak-associated isolates using pulsed-field gel electrophoresis (PFGE) revealed two similar but distinct AscI PFGE patterns. High-throughput pyrosequencing of two L. monocytogenes isolates was used to rapidly provide the genome sequence of the primary outbreak strain and to investigate the extent of genetic diversity associated with a change of a single restriction enzyme fragment during PFGE. RESULTS The chromosomes were collinear, but differences included 28 single nucleotide polymorphisms (SNPs) and three indels, including a 33 kbp prophage that accounted for the observed difference in AscI PFGE patterns. The distribution of these traits was assessed within further clinical, environmental and food isolates associated with the outbreak, and this comparison indicated that three distinct, but highly related strains may have been involved in this nationwide outbreak. Notably, these two isolates were found to harbor a 50 kbp putative mobile genomic island encoding translocation and efflux functions that has not been observed in other Listeria genomes. CONCLUSIONS High-throughput genome sequencing provided a more detailed real-time assessment of genetic traits characteristic of the outbreak strains than could be achieved with routine subtyping methods. This study confirms that the latest generation of DNA sequencing technologies can be applied during high priority public health events, and laboratories need to prepare for this inevitability and assess how to properly analyze and interpret whole genome sequences in the context of molecular epidemiology.
Collapse
Affiliation(s)
- Matthew W Gilmour
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Orsi RH, Bowen BM, Wiedmann M. Homopolymeric tracts represent a general regulatory mechanism in prokaryotes. BMC Genomics 2010; 11:102. [PMID: 20144225 PMCID: PMC2831843 DOI: 10.1186/1471-2164-11-102] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 02/09/2010] [Indexed: 11/16/2022] Open
Abstract
Background While, traditionally, regulation of gene expression can be grouped into transcriptional, translational, and post-translational mechanisms, some mechanisms of rapid genetic variation can also contribute to regulation of gene expression, e.g., phase variation. Results We show here that prokaryotes evolved to include homopolymeric tracts (HTs) within coding genes as a system that allows for efficient gene inactivation. Analyses of 81 bacterial and 18 archaeal genomes showed that poly(A) and poly(T) HTs are overrepresented in these genomes and preferentially located at the 5' end of coding genes. Location of HTs at the 5' end is not driven by a preferential placement of aminoacids encoded by the AAA and TTT codons at the N-terminal of proteins. The inlA gene of the pathogen L. monocytogenes was used as a model to further study the role of HTs in reversible gene inactivation. In a number of L. monocytogenes strains, inlA harbors a 5' poly(A) HT, which regularly shows frameshift mutation leading to expression of a truncated 8 aa InlA protein. Translational fusions of the inlA 5' end allowed us to estimate that the frequency of variation in this HT is about 1,000 fold higher than the estimated average point mutation frequency. Conclusions As frameshift mutations in HTs can occur at high frequencies and enable efficient gene inactivation, hypermutable HTs appear to represent a universal system for regulation of gene expression in prokaryotes. Combined with other studies indicating that HTs also enable rapid diversification of both coding and regulatory genetic sequences in eukaryotes, our data suggest that hypermutable HTs represent a general and rapid evolutionary mechanism facilitating adaptation and gene regulation across diverse organisms.
Collapse
Affiliation(s)
- Renato H Orsi
- Department of Food Science, Cornell University, Ithaca, NY 14853, USA.
| | | | | |
Collapse
|