調查來自同一檢體的imipenem-resistant Enterobactericeae菌株之抗藥相關性

Drug Resistance Relationship Analysis of Three Imipenem-resistant Enterobactericeae Isolated from the Same Patient's Samples

南台灣的某區域醫院，在103年3月18日從一位安養中心住民的尿液培出二株對imipenem具有抗藥性的腸內菌，一株是Providencia stuartii（IRPS, P2），一株是Klebsiella pneumoniae（IRKP, K1）。這位病患也曾在103年2月14日的尿液培養出一株IRPS（P1），因此我們使用分子生物學方法研究此二株IRPS與一株IRKP抗藥性機轉的相關性。抗生素敏感試驗顯示這三株細菌除了對meropenem具有敏感性外，對大部分被測試的抗生素都具有抗藥性。脈衝式電泳分析法證實P1及P2是來自相同的clone。此外，P2與K1都含有一個180 kb的IncA/C質體，其中都帶有blaCMY-2、qnr與aac（6'）-Ib-cr基因。限制性片段長度多型性（restriction fragment length polymorphism, RFLP）分析證實P1、P2及K1的180kb的質體幾乎相同，因此K1的抗藥性質體可能與來自P1,P2的質體同源。結果顯示菌株散播及抗藥性質體的傳播可能是安養中心具有高比率抗藥性細菌的原因。 At a regional hospital in southern Taiwan, two strains of imipenem-resistant Enterobactericeae were isolated from the urine sample of a patient from a nursing home on 18 May 2014, including Providencia stuartii (IRPS, P2) and Klebsiella pneumoniae (IRKP, K1). On 13 February 2014, one IRPS (P1) was also isolated from the urine sample of this patient. Hence, we investigated antibiotic-resistant relationship of the two IRPS and one IRKP. Antimicrobial susceptibility testing revealed the three isolates were resistant to most antibiotics tested, except meropenem. Pulsed-field gel electrophoresis (PFGE) results showed P1 and P2 are originated from the same clone. Both P2 and K1 had 180 kb IncA/C plasmids that carried blaCMY-2、qnr and aac(6')-Ib-cr genes. Further, restriction fragment length polymorphism analysis indicated that the 180 kb plasmids of P1, P2, and K1 were almost identical. Results strongly indicated a close relationship among the antibiotic-resistant plasmids of K1, P1 and P2. Thus bacterial clonal spread and the spread of antibiotic-resistant plasmid may play important roles of bacterial high drug resistance prevalence at nursing home.