Drug tolerance and PFGE molecular typing of Salmonella paratyphi A isolated in Dengfeng,Henan province, 2009-2015 / 中华流行病学杂志

ABSTRACT

Objective To investigate the drug tolerance and PFGE patterns of Salrnonella (S.) paratyphi A strains isolated from sentinel hospitals in Dengfeng,Henan province,during 2009-2015.Methods Venous blood samples were collected from paratyphoid patients and cultured in double phase blood culture bottle.Suspicious strains were identified and used for Salomonella.O antigen and H1/2 phase flagellum-induced serum agglutination test with API20E biochemical systems and SSI Salmonella typing sera.According to Salmonella molecular typing and K-B drug susceptibility testing method published by PulseNet China bacterial infectious disease monitoring network and USA Clinical and Laboratory Standards Institute,we analyzed the drug susceptibility and PFGE molecule characteristics of S.paratyphiA strains isolated from the patients.Results A total of126 strains of S.paratyphi A were isolated from 248 blood samples,the antigen modes of them were 1,2,12a-.The resistance rate of 126 strains of S.paratyphi A was 83.3％ to ampicillin;29.4％ to ceftazidime,31.2％ to cefotaxime,17.5％ to cefepime;62.6％ to nalidixic acid;19.3％ to ciprofloxacin,26.4％ to norfloxacin;22.8％ to gentamicin,47.9％ to streptomycin;19.2％ to chloramphenicol,24.2％ to methicillin benzyl ammonium,58.6％ to compound sulfamethoxazole and 46.7％ to tetracycline.The 126 strains of S.paratyphi A had different levels of resistance to 8 kinds of antibiotics,109 strains were multidrug resistant (86.5％),9 strains were resistant to 2-3 kinds of antibiotics (7.1％),76 strains were resistant to 5-8 kinds of antibiotics (60.3％),17 strains were resistant to 9-10 kinds of antibiotics (13.5％),7 strains were resistant to 11-12 kinds of antibiotics (5.6％).The 126 strains of S.paratyphi A were divided into 14 molecular patterns by digestion with Xba I and pulsed field gel electrophoresis.The antibiotics resistance to third generation cephalosporin (CAZ,CTX),one generation and three generation of quinolones (NAL,CIP,NOR) and aminoglycosides antibiotics (STR) showed an upward trend.Each pattem contained 1-98 strains with similarity ranged from 64.10％ to 100.00％.PTYA 1,6,9 and 10 were the main PFGE belt types.Conclusion The drug resistance of clinical isolates ofS.paratyphi A was serious in Dengfeng,Henan province,PFGE pattems showed a diversity,but predominant patterns could also be found.The PFGE patterns of some strains had clustering and were related with their antidrug spectrums.