Vervoort J, Gazin M, Kazma M, Kotlovsky T, Lammens C, Carmeli Y, Goossens H, Malhotra-Kumar S
Department of Medical Microbiology, Vaccine & Infectious Disease Institute, University of Antwerp, Antwerp, Belgium.
Eur J Clin Microbiol Infect Dis. 2014 Dec;33(12):2215-21. doi: 10.1007/s10096-014-2193-9. Epub 2014 Jul 4.
The purposes of this study were to investigate the intestinal carriage of extended-spectrum β-lactamase-harbouring Enterobacteriaceae (ESBL-EN) and associated fluoroquinolone resistance (FQ-R) in 120 hospitalised patients with antibiotic-associated diarrhoea, and to investigate a correlation between Clostridium difficile (C. difficile) infection and intestinal colonisation with ESBL-EN in these patients. Stool samples were screened for C. difficile infection by toxin A/B enzyme-linked immunosorbent assay (ELISA) and for the presence of enterobacterial isolates producing β-lactamases by plating on β-lactamase screening (BLSE) agar. Recovered isolates were confirmed pheno- and genotypically for the presence of ESBL genes (bla CTX-M, bla TEM, bla SHV) by the double-disc synergy test and polymerase chain reaction (PCR) sequencing, and tested for the presence of topoisomerase mutations (gyrA, parC) and plasmid-mediated quinolone resistance (PMQR) determinants [qnrA, qnrB, qnrS, qepA, aac(6')-Ib-cr] by PCR sequencing. ESBL-EN were detected in 44/120 (37 %) stool samples. C. difficile-infected patients showed a significantly higher frequency of intestinal colonisation with ESBL-EN compared to C. difficile non-infected patients (62 % vs. 31 %, p = 0.008). Of the 73 ESBL-EN recovered, 46 (63 %) showed high-level FQ-R [ciprofloxacin minimum inhibitory concentration (MIC) ≥32 mg/L]. The largest group consisted of 21 bla CTX-M-15-harbouring Enterobacteriaceae (ciprofloxacin MIC ≥64 mg/L) with multiple topoisomerase mutations in gyrA and parC, in combination with co-carriage of aac(6')-Ib-cr. Most of them were Escherichia coli isolates belonging to sequence types ST131 and ST410. We found remarkably high rates of intestinal colonisation with high-level FQ-R ESBL-EN in hospitalised patients with antibiotic-associated diarrhoea, especially among C. difficile-infected patients. These data underscore the need for stringent infection control to contain this potentially infectious and multidrug-resistant reservoir.
本研究的目的是调查120例抗生素相关性腹泻住院患者中携带超广谱β-内酰胺酶的肠杆菌科细菌（ESBL-EN）及其相关氟喹诺酮耐药性（FQ-R）的肠道携带情况，并调查这些患者中艰难梭菌（C. difficile）感染与ESBL-EN肠道定植之间的相关性。通过毒素A/B酶联免疫吸附测定（ELISA）筛查粪便样本中的艰难梭菌感染，并通过接种于β-内酰胺酶筛选（BLSE）琼脂平板检测产β-内酰胺酶的肠杆菌分离株的存在。通过双纸片协同试验和聚合酶链反应（PCR）测序对回收的分离株进行ESBL基因（bla CTX-M、bla TEM、bla SHV）存在情况的表型和基因型确认，并通过PCR测序检测拓扑异构酶突变（gyrA、parC）和质粒介导的喹诺酮耐药性（PMQR）决定簇[qnrA、qnrB、qnrS、qepA、aac(6')-Ib-cr]的存在情况。在44/120（37%）的粪便样本中检测到ESBL-EN。与未感染艰难梭菌的患者相比，感染艰难梭菌的患者ESBL-EN肠道定植频率显著更高（62%对31%，p = 0.008）。在回收的73株ESBL-EN中，46株（63%）表现出高水平FQ-R[环丙沙星最低抑菌浓度（MIC）≥32 mg/L]。最大的一组由21株携带bla CTX-M-15的肠杆菌科细菌组成（环丙沙星MIC≥64 mg/L），其gyrA和parC存在多个拓扑异构酶突变，并伴有aac(6')-Ib-cr的共同携带。其中大多数是属于序列类型ST131和ST410的大肠杆菌分离株。我们发现，抗生素相关性腹泻住院患者中高水平FQ-R ESBL-EN的肠道定植率非常高，尤其是在感染艰难梭菌的患者中。这些数据强调了进行严格感染控制以遏制这种潜在感染性和多重耐药菌库的必要性。
