Characterization of a P1-like bacteriophage carrying CTX-M-27 in Salmonella spp. resistant to third generation cephalosporins isolated from pork in China

• Published in: Scientific reports 2017-01, Vol.7 (1), p.40710-40710, Article 40710
• Main Authors: Yang, Ling, Li, Wan, Jiang, Gui-Ze, Zhang, Wen-Hui, Ding, Huan-Zhong, Liu, Ya-Hong, Zeng, Zhen-Ling, Jiang, Hong-Xia
• Format: Article
• Language: English
• Subjects: 42; 45/22; 45/23; 45/77; 631/326/22/1434; 631/326/421; Abattoirs; Antibiotics; Antimicrobial resistance; Cephalosporins; Epidemiology; Humanities and Social Sciences; Incp plasmids; multidisciplinary; Phages; Plasmids; Pork; Salmonella; Science; Serotypes; Typing
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep40710

The aim of this study was to elucidate the epidemiology of third generation cephalosporin resistant Samonella isolates from pork of a slaughterhouse in China and the features of transferable elements carrying bla CTX-M genes. One hundred and twenty-six (7.3%) Salmonella isolates were identified; S . Derby and S . Rissen were the most two prevalent serotypes. Among these isolates 20 (15.8%) were resistant to third generation cephalosporins and nine of them carried bla CTX-M-27 . S1-PFGE and replicon typing of bla CTX-M-27 -carrying plasmids showed that seven were untypeable plasmids of about 104 Kb and two were IncP plasmids of about 300 Kb. Complete sequence analysis of one PBRT-untypeable plasmid showed it was a P1-like bateriophage, named SJ46, which contained a non-phage-associated region with several mobile elements, including Tn1721, IS Ecp1B and IS903D. The other six 104 Kb PBRT-untypeable bla CTX-M-27 -carrying plasmids also harboured the same phage-insertion region of SJ46 suggesting that they were the same P1-like bacteriophage. PFGE profiles of the parental strains revealed both potential vertical and horizontal spread of this P1-like bla CTX-M-27 -containing element. Additionally, the representative gene of the P1 family bacteriophage, repL , was detected in 19.0% (24/126) of the isolates. This study indicated a potential role of P1-family bacteriophage in capture and spread of antimicrobial resistance in pathogens.