Quinteros M, Radice M, Gardella N, Rodriguez M M, Costa N, Korbenfeld D, Couto E, Gutkind G
Hospital de Enfermedades Infecciosas "F J Muñiz" Facultad de Bioquímica y Farmacia UBA, Buenos Aires, Argentina.
Antimicrob Agents Chemother. 2003 Sep;47(9):2864-7. doi: 10.1128/AAC.47.9.2864-2867.2003.
Resistance to extended-spectrum cephalosporins is often associated with plasmid encoded extended spectrum beta-lactamases (ESBL). In order to evaluate the prevalence and diversity of ESBLs in enterobacteria in our city, a 1-month-period survey was carried out from April to May 2000. Extended-spectrum-cephalosporin-resistant strains, isolated from inpatient clinical specimens other than stools, were collected among 17 participating hospitals. From a total of 427 enterobacterial strains that were collected during this period, 39 were extended-spectrum cephalosporin resistant. The National Committee for Clinical Laboratory Standards' Screening and Confirmatory Tests for ESBL production were performed using cefotaxime and ceftazidime; cefepime and cefepime-clavulanic acid-containing disks were included. beta-Lactamases were characterized by isoelectric focusing and PCR amplification using specific primers. Three different ESBLs were detected: SHV-related (4 isolates), PER-2-type (9 isolates), and CTX-M-2-related (26 isolates). Sequencing of the corresponding genes confirmed CTX-M-2 in 19 of 21 and CTX-M-31 (an allelic variant) in the remaining 2 of 21. CTX-M-2 (or its variant) was detected in all Escherichia coli, Enterobacter aerogenes, Serratia marcescens, Proteus mirabilis, and Providencia stuartii strains, while PER-2 was detected in Enterobacter cloacae, E. aerogenes, and Klebsiella pneumoniae; SHV-related ESBL were found only in K. pneumoniae. These results clearly show that CTX-M-2 is the most prevalent ESBL produced by enterobacterial species isolated from public hospitals in Buenos Aires.
对超广谱头孢菌素的耐药性通常与质粒编码的超广谱β-内酰胺酶（ESBL）有关。为了评估我市肠杆菌科细菌中ESBL的流行情况和多样性，于2000年4月至5月进行了为期1个月的调查。从17家参与调查的医院收集了从住院患者粪便以外的临床标本中分离出的对超广谱头孢菌素耐药的菌株。在此期间共收集了427株肠杆菌科细菌，其中39株对超广谱头孢菌素耐药。使用头孢噻肟和头孢他啶按照美国国家临床实验室标准委员会的ESBL产生筛选和确证试验进行检测；还包括头孢吡肟和含头孢吡肟-克拉维酸的纸片。通过等电聚焦和使用特异性引物的PCR扩增对β-内酰胺酶进行鉴定。检测到三种不同的ESBL：SHV相关型（4株）、PER-2型（9株）和CTX-M-2相关型（26株）。相应基因的测序在21株中的19株中确认了CTX-M-2，在其余2株中确认了CTX-M-31（一种等位变体）。在所有大肠杆菌、产气肠杆菌、粘质沙雷氏菌、奇异变形杆菌和斯氏普罗威登斯菌菌株中均检测到CTX-M-2（或其变体），而在阴沟肠杆菌、产气肠杆菌和肺炎克雷伯菌中检测到PER-2；仅在肺炎克雷伯菌中发现了SHV相关的ESBL。这些结果清楚地表明，CTX-M-2是从布宜诺斯艾利斯公立医院分离出的肠杆菌科细菌产生的最常见的ESBL。
