云南某医院多耐药E.coli和K.pneumoniae分子流行病学分析

Molecular epidemiological analysis of multi-drug resistant E. coli and K.pneumoniae isolates in Yunnan, China

目的分析云南某医院E.coli和K.pneumonia菌耐药基因分子流行病学特征。方法全自动微生物分析仪分类鉴定菌株及抗生素敏感试验。扩增并序列分析耐药基因。MLST及PFGE分析菌株遗传变异关系。结果共收集23株E.coli菌和9株K.pneumonia菌,除了1株XDR K.pneumoniae,其余均为MDR菌。全部菌株对一代、二代头孢霉素,甚至三代头孢霉素CRO耐药。绝大多数菌株对氟化奎林酮类、氨基苷类及磺胺类抗生素耐药。39.1%和69.6%E.coli携带blaTEM和blaCTX基因,而44.4%和100.0%K.pneumoniae检测到blaTEM和blaCTX基因。bla TEM均为TEM-1基因型。CTX-M-55及CTX-M-15为该地区优势基因型。所有K.pneumonia菌株携带blaSHV基因,SHV-11为优势型。87.5%E.coli和77.8%K.pneumoniae菌株携带ISEcp1。91.3%E.coli和77.8%K.pneumoniae携带int1。44.4%K.pneumoniae携带ISCR1基因。PFGE及MLST研究显示菌株存在明显的遗传多态性。结论云南该医院多重耐药E.coli和K.pneumonia菌呈高度流行,耐药基因在不同菌株及菌种间快速传播。

Objective To analyze molecular epidemiologieal characteristics of the drug resistance of local E. coli and K. pneumoniae isolates obtained from a hospital in Yunnan Province. Methods Identification and antimicrobial snsceptibility testing （AST） for all the isolates were conducted using the VITEKw2 system. ESBL genes were amplified and sequenced. PFGE and MIST were performed to understand clonally relationship among these isolates. Results The 23 E.coli strains and 9 K. pneumoniae strains except 1 （XDR） K. pneumoniae isolate were MDR and all of the E. coli and K. pneumoniae isolates were resistant to the ampicill∽n, cefuroxim, cefazolin and ceftriaxone. Moreover, most K. pneumoniae and E. eoli isolates were resistant to aztreonam, ampiciUin/sulbactam and ceftazidime. 39.1% of E. coli and 44.4% of K. pneumoniae isolates shared blnrEM gene, and 69.6 % of E. coli and 100.0% of K. pneumoniae isolates carried blaCTX, blarEM were TEM-I gene, and leading genotypes were CTX-M-55 and CTX-M-15. All K. pneumoniae isolates shared blas∽ genes, with the dominant SHV-11 genotype. 87.5% of E. coli isolates and 77.8% of K. pneumoniae isolates carried the ISEcpl gene, 91.3% of E. coli isolates and 77.8% of K. pneumoniae isolates shared the intl gene, and 44.4% of K. pneumoniae isolates carried the IS CR1 gene. Genetically heterogeneous isolates were confirmed by MIST and PFGE analysis. Conclusions Polyclonal spread of MDR E. coli and K. pneumoniae isolates occurred among clinical isolates in local regions.