江苏省2012-2015年伤寒/副伤寒沙门菌耐药及分子分型研究

目的 回顾性分析2012-2015年江苏省伤寒/副伤寒沙门菌的耐药表型和分子分型特征。方法 采集江苏省伤寒/副伤寒监测病例的血液和粪便标本，分离培养伤寒/副伤寒沙门菌后进行生化鉴定和血清分型；采用Kirby-Bauer纸片法检测菌株对抗菌药物的敏感性；应用PFGE技术对伤寒和甲型副伤寒沙门菌进行分子分型。结果 134株伤寒沙门菌和甲型副伤寒沙门菌对萘啶酸的耐药率最高，分别为61.2%和86.7%，其余抗生素的耐药率均低于15.0%。伤寒和甲型副伤寒沙门菌中只耐1种抗生素的菌株最多，多重耐药菌在伤寒沙门菌中占2.6%，而在甲型副伤寒沙门菌中占13.3%。2015年伤寒沙门菌的全敏感菌株构成比较2012年增加了44.3%，同年副伤寒沙门菌中出现了耐5种和6种抗生素的多重耐药株。甲型副伤寒沙门菌可分为8种PFGE型别，多重耐药株与其他菌株条带相似性低，不同型别与耐药谱有对应关系；伤寒沙门菌可分为68种PFGE型别，不同型别间变异度较大，与耐药谱无对应关系。结论 2012-2015年江苏省伤寒/副伤寒沙门菌对抗生素的耐药性总体随时间降低，耐药种类数有所增加。伤寒沙门菌株PFGE带型呈现多样性，无耐药谱对应性；而甲型副伤寒菌株PFGE带型较少，有耐药谱对应性。需要加强重点地区重点型别菌株的监测。

Antimicrobial resistance and molecular subtypes of Salmonella typhi and Salmonella paratyphoid isolates from Jiangsu province, 2012-2015

Objective To retrospectively analyze the antimicrobial resistance phenotype and molecular typing characteristics of Salmonella (S.) typhi and S. paratyphi in Jiangsu province from 2012 to 2015. Methods The samples were collected from typhoid and paratyphoid patients in Jiangsu province. The biochemical identification and serotyping were carried out after isolation and culture. Kirby-Bauer (K-B) testing was used to detect the drug susceptibility of the strains. The molecular typing characteristics of S. typhi and S. paratyphi were analyzed by pulsed field gel electrophoresis (PFGE). Results The resistant rates of 134 S. typhi and S. paratyphi A strains to nalidixic acid were highest (61.2% and 86.7%), while the resistant rates to remaining antibiotics were less than 15.0%. Most of S. typhi and S. paratyphi A strains were resistant to only one antibiotic. Multidrug-resistant (MDR) strains of S. typhi and S. paratyphi A accounted for 2.6% and 13.3% respectively. The composition of the all-sensitive strains of S. typhi increased by 44.3% in 2015, at the same time, there were also MDR S. paratyphi A strains, which were resistant to 5 and 6 antibiotics. S. paratyphi A could be divided into eight molecular patterns by PFGE, showing that the similarity between the MDR strains and other strains was relatively low. The S. paratyphi A strains with same pattern were resistant to same antibiotics. S. typhi could be divided into 68 molecular patterns by PFGE, with large variability between different patterns. There was no corresponding relationship between the patterns and the drug resistance characteristics. Conclusions The overall antibiotic resistance of S. typhi and S. paratyphi A strains showed a decreasing trend, but the number of antibiotics to which they were resistant increased. PFGE patterns of S. typhi showed diversity without correspondence to antibiotic characteristics. PFGE patterns of S. paratyphi A were less with correspondence to antibiotic characteristics. We should pay more attention to key patterns in key areas.