title: Molecular subtyping and virulence gene analysis of Listeria monocytogenes isolates from food.
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.
authors.affiliation: College of Food Science and Engineering, Northwest A&F University, Yangling, Shaanxi Province 712100, China.
authors.forename: Jinling
authors.initials: J
authors.lastname: Shen
authors.forename: Lydia
authors.initials: L
authors.lastname: Rump
authors.forename: Yifan
authors.initials: Y
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Chen
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Jianghong
authors.initials: J
authors.lastname: Meng
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins / Q000235:genetics; D015373:Bacterial Typing Techniques / Q000379:methods*; D002939:Ciprofloxacin / Q000494:pharmacology; D003001:Cloning, Molecular; D024881:Drug Resistance, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology; D006360:Heat-Shock Proteins / Q000235:genetics; D006460:Hemolysin Proteins / Q000235:genetics; D008089:Listeria monocytogenes / Q000145:classification / Q000187:drug effects / Q000302:isolation & purification* / Q000472:pathogenicity; D008460:Meat / Q000382:microbiology*; D008826:Microbial Sensitivity Tests; D009582:Nitrofurantoin / Q000494:pharmacology; D010802:Phylogeny; D012703:Serotyping; D013752:Tetracycline / Q000494:pharmacology; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D006360:Heat-Shock Proteins; D006460:Hemolysin Proteins; C069761:internalin protein, Bacteria; D002939:Ciprofloxacin; D009582:Nitrofurantoin; D013752:Tetracycline; C038705:hlyA protein, Listeria monocytogenes