Antimicrobial resistance and epidemiology of ESBLs-producing Escherichia coli and Enterobacter cloacae isolates from the intensive care unit in an affiliated hospital of University, China

Abstract

Background：Concerns are increasing over the importance of the hospital intensive care units (ICU) for the transmission of extended spectrum-β-lactamase (ESBLs) -producing Enterobacteriaceae. We reported the clinical characteristics and epidemiology of ESBLs isolates collected from a tertiary care hospital in China. Methods：Escherichia coli（E. coli）and Enterobacter cloacae （E. cloacae）isolates from ICU infection samples were isolated and identified. Antimicrobial susceptibility profiles and production of ESBLs were determined by using the disk diffusion method and the broth microdilution method. Clonality of isolates was determined by ERIC-PCR techniques. Results：From the included the 223 strains isolated from hospitalized patients with nosocomial infections in ICU during 2016 to 2018, the majority of isolates belonged to Gram-negative Enerobacteriaceae including E. coli (46.6% of all strains), and E. cloacae (46.2% of all strains). 63.25% of samples were separated from sputum or tracheal secretions. All of 207 isolates, ESBL-screen positive E. coli was 45.2% (47/104), and 44.7% (46/103) for E. cloacae. Resistance rates of ESBLs-producing E. coli and E. cloacae isolates were 95.5%-91.3% for ampicillin, 80.6%-76.1% for ampicillin/azobactam, 88.1%-28.3% for ciprofloxacin, 89.6%-15.2% for levofloxacin, 34.3%-45.7% for netilmicin, 82.1%-41.3% for compound sulfamethoxazole, 20.9%-43.5% for amikacin, 58.2%-37.0% for gentamicin, 20.9%-69.6% for piperacillin/tazobactam. All of ESBLs-producer isolates resistant to cefazolin, cefuroxime, ceftazidime, ceftriaxone, cefepime in additon to aztreonam were 100%, whereas the susceptibilities of isolates to imipenem and meropenem were 100%. Results of ERIC-PCR in all of ESBLs-producing E. coli isolates exhibited 11 distinct patterns using a similarity coefficient of 0.8. And one distinct ERIC profiles were observed amongst 46 strains of ESBLs-producing E. cloacae. ERIC profiles demonstrated an outbreak of nosocomial infection and ESBLs-producing E. coli and E. cloacae prevalent in the ICU of this hospital.Conclusions：Our data indicate that the ESBLs-producing E. coli and E. cloacae clones are circulating in the ICU and constitute a major source for further disseminating in this hospital. It is necessary to increase surveillance and development of adequate prevention strategies.