成都地区血浆凝固酶阴性葡萄球菌耐药性及分子流行病学分析

Antimicrobial resistance and molecular epidemiology of coagulase-negative Staphylococci in Chengdu

目的探讨成都地区血浆凝固酶阴性葡萄球菌(CoNS)耐药性及分子流行病学特征。方法采集成都市15所医院和6所疾病预防控制中心分离的不重复的2038株CoNS,按NCCLS推荐的方法和判断标准进行药敏试验。同时将CoNS作质粒和PFGE分型。结果(1)CoNS以表皮葡萄球菌、溶血葡萄球菌和腐生葡萄球菌为主,3种葡萄球菌占CoNS的82.2%,不同来源菌株的构成不完全一致。(2)CoNS对一种及一种以上抗菌药物有耐药性,耐药率为80.4%,对复方新诺明(SMZ)、青霉素G、氨苄青霉素、红霉素、TMP-SMZ和四环素等抗菌药物有较高的耐药性,对万古霉素、氟哌酸、丁胺卡那霉素较敏感。共检出25种耐药谱型,主要耐药谱型为氨苄青霉素+红霉素+青霉素G+SMZ、氨苄青霉素+庆大霉素+链霉素+四环素、氨苄青霉素+青霉素G+四环素、链霉素+红霉素+青霉素G+SMZ+TMP-SMZ、红霉素+新生霉素+青霉素G+SMZ+TMP-SMZ和青霉素G+SMZ+TMP-SMZ。不同来源CoNS的主要耐药谱型不完全一致,主要生化型别CoNS耐药性表现出一定的相似性。(3)CoNS质粒检出率为72.9%,共分为12个质粒谱型(Ⅰ-Ⅻ),以Ⅰ、Ⅱ、Ⅲ型为主,3个型别占1485株携带质粒的CoNS的80.1%。(4)CoNS共有29种PFGE谱型和112个亚型,A、B、C、D、E等5型占总数的89.1%,在不同来源的CoNS中均为优势基因型。不同来源的CoNS中A型具有较相似的构成比且均为最主要的基因型,其它几种优势基因型的构成缺乏相似性。结论本地区CoNS耐药率相当高,多重耐药的现象普遍存在于不同类型的人群中。不同来源CoNS尤其是来自医务人员和患儿的CoNS有很高的同源性,存在着互相传播的潜在可能。

Objective To investigate the antimicrobial resistance and molecular prevalence of coagulase-negative Staphylococcus （CONS） in Chengdu. Methods Disk diffusion method was used to test antimicrobial resistance of 2038 CoNS isolated from 15 hospitals and 6 CDCs （center for disease control and prevention） in Chengdu, the results were interpreted according to the guideline of National Committee for Clinical Laboratory Standards. CoNS were typed with plasmid and PFGE （pulsed field gel electrophoresis） profiles. Results （1） S. epidermidis, S. haemolyticus, and S. saporophyticus accounted for 82.2% of the CoNS isolated from Chengdu, with different constituent ratio of CoNS among patients, medical staff, sick children and normal people. （2） CoNS resisted to one or more antimicrobial agents with resistance rate of 80.4%. CoNS resisted highly to SMZ, penicillin-G, ampicillin, erythromycin, TMP-SMZ and tetracycline, but were susceptible to vancomycin, norfloxacin and amikacin. 25 antimicrobial resistance profiles were acquired, and Amp＋Ery＋P-G＋SMZ, Amp＋Gen＋Str＋Tet, Amp＋P-G＋Tet, ChI＋Ery＋P-G＋SMZ＋TS, Ern＋ Nov ＋ P-G ＋ SMZ ＋ TS, as well as P-G ＋ SMZ ＋ TS were main profiles. The main antimicrobial resistance profiles of CoNS isolated from patients, medical staff, sick children and normal people had some differences, but the antimicrobial resistance of main biochemical subtypes was similar a lot. （3） Plasmid prevalence of CoNS was 72.9% , with 12 plasmid profiles （ Ⅰ - Ⅻ ） of all CONS. The main profiles were Ⅰ , Ⅱ , and Ⅲ type, which accounted for 80.1% of 1485 CoNS with plasmid. （4） 29 PFGE genotypes and 112 subtypes were found in 2038 strains. C.enotypes A, B, C, D and E were the predominant types in CoNS from patients, medical staff, sick children and normal people and contributed 89.1% to 2038 CONS. C.enotypes A was the major type and had similar constituent ratio in CoNS from 4 sources, and no enough similarity of constituent ratio in other dominant genotypes. Conclusion Antimicrobial resistance rate of CoNS was very high in Chengdu and multi-resistance existed in various populations generally. High homology was found in CoNS from different sources, especially from medical staff as well as sick children and infant, and a latent inter-transmission may occur in these populations. So it was no time to delay the monitoring and investigation of antimicrobial resistance and molecular epidemiology for CoNS in Chengdu.