title: Extended-spectrum beta-lactamases in enterobacteriaceae in Buenos Aires, Argentina, public hospitals.
abstract: 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.
authors.affiliation: Hospital de Enfermedades Infecciosas "F J Muñiz" Facultad de Bioquímica y Farmacia UBA, Buenos Aires, Argentina.
authors.forename: M
authors.initials: M
authors.lastname: Quinteros
authors.forename: M
authors.initials: M
authors.lastname: Radice
authors.forename: N
authors.initials: N
authors.lastname: Gardella
authors.forename: M M
authors.initials: MM
authors.lastname: Rodriguez
authors.forename: N
authors.initials: N
authors.lastname: Costa
authors.forename: D
authors.initials: D
authors.lastname: Korbenfeld
authors.forename: E
authors.initials: E
authors.lastname: Couto
authors.forename: G
authors.initials: G
authors.lastname: Gutkind
mesh_terms: D001118:Argentina / Q000453:epidemiology; D019818:Clavulanic Acid / Q000494:pharmacology; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology*; D004756:Enterobacteriaceae Infections / Q000453:epidemiology / Q000382:microbiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006779:Hospitals, Public; D006801:Humans; D007525:Isoelectric Focusing; D008826:Microbial Sensitivity Tests; D020133:Reverse Transcriptase Polymerase Chain Reaction; D065093:beta-Lactamase Inhibitors; D001618:beta-Lactamases / Q000737:chemistry* / Q000302:isolation & purification
chemical_list: D004791:Enzyme Inhibitors; D065093:beta-Lactamase Inhibitors; D019818:Clavulanic Acid; D001618:beta-Lactamases