title: Staphylococcus aureus ST6-t701 isolates from food-poisoning outbreaks (2006-2013) in Xi'an, China.
abstract: The aim of the study was to investigate the molecular epidemiologic of Staphylococcus aureus isolated from seven staphylococcal food-poisoning (SFP) outbreaks between 2006 and 2013 in Xi'an, northwest China. A total of seven S. aureus isolates associated with seven SFP outbreaks were obtained and characterized by determining the multilocus sequence typing, spa typing, pulsed-field gel electrophoresis (PFGE), antimicrobial susceptibility, toxin and resistant genes. The results showed that S. aureus ST6-t701 (71.4%) was the most predominant clone, followed by ST5-t002 and ST59-t172 (each 14.3%). Seven different PFGE patterns were obtained. Moreover, resistance was most frequently observed to trimethoprim and penicillin (each 71.4%), followed by erythromycin (28.6%), ampicillin, clindamycin, and tetracycline (each 14.3%). All strains were susceptible to chloramphenicol, cefoxitin, oxacillin, amikacin, and vancomycin. Three of seven strains displayed resistance to three or more antimicrobials. Resistance genes were found as follows: linA/linA' (100%), blaZ (85.7%), tet(K), ermC, ermT, and ermB (each 14.3%). Other resistant genes were not detected. In addition, the most frequently identified exotoxin genes were seu, lukED, hla, hlb, hld (each 100%), followed by hlg and hlgv (each 85.7%), lukPV (71.4%), sea (57.1%), see (42.9%), etd (28.6%), and seb, sec, sed, sej, and sek (each 14.3%). The results indicated that S. aureus ST6-t701, with a high prevalence in the northwest of China, exhibited multidrug resistance and harbored multiple toxin and resistance genes. Therefore, strict hygienic and preventative measures should be taken in order to avoid the contamination of food by S. aureus and toxin production in foods.
authors.affiliation: 1 College of Food Science and Engineering, Northwest A&F University , Yangling, Shaanxi, China .
authors.forename: Guanghui
authors.initials: G
authors.lastname: Li
authors.forename: Shouzhi
authors.initials: S
authors.lastname: Wu
authors.forename: Wen
authors.initials: W
authors.lastname: Luo
authors.forename: Yulan
authors.initials: Y
authors.lastname: Su
authors.forename: Yang
authors.initials: Y
authors.lastname: Luan
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002681:China / Q000453:epidemiology; D004196:Disease Outbreaks; D024901:Drug Resistance, Multiple, Bacterial / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D004768:Enterotoxins / Q000235:genetics*; D005098:Exotoxins / Q000235:genetics*; D005516:Food Microbiology; D006801:Humans; D008826:Microbial Sensitivity Tests; D058889:Molecular Typing; D058885:Multilocus Sequence Typing; D013202:Staphylococcal Food Poisoning / Q000453:epidemiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000302:isolation & purification*; D037521:Virulence Factors / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D004768:Enterotoxins; D005098:Exotoxins; D037521:Virulence Factors