title: Dissemination of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae and Escherichia coli in Thai hospitals.
abstract: Fifty clinical isolates of Klebsiella pneumoniae and Escherichia coli with reduced susceptibility to third-generation cephalosporins, collected from 11 hospitals in Thailand, were studied. All isolates were found to produce extended-spectrum beta-lactamase (ESBL), as judged by double-disk synergy and combination disk methods. Most ESBL-producing K. pneumoniae isolates were resistant to ceftazidime (94%) and aztreonam (90%). In contrast, most ESBL-producing E. coli isolates were resistant to ceftriaxone (95%) and cefotaxime (74%). Plasmid DNA was isolated and beta-lactamase genes were identified by PCR and sequencing. We found that SHV-12 and CTX-M-14 were the main ESBLs responsible for resistance in K. pneumoniae and E. coli, respectively. SHV-27, SHV-28, and CTX-M-14 were detected in three, two, and four K. pneumoniae isolates, respectively. A high genetic diversity among ESBL-producing K. pneumoniae and E. coli isolates was observed. In addition, the finding of a few isolates that produced identical restriction patterns on pulsed field gel electrophoresis (PFGE) suggests the clonal spread of resistant bacteria within the hospital.
authors.affiliation: Department of Microbiology and Parasitology, Faculty of Medical Science, Naresuan University, Phitsanulok, 65000, Thailand. pannikan@nu.ac.th
authors.forename: Pannika R
authors.initials: PR
authors.lastname: Niumsup
authors.forename: Uttapoln
authors.initials: U
authors.lastname: Tansawai
authors.forename: Nitsara
authors.initials: N
authors.lastname: Boonkerd
authors.forename: Pitimon
authors.initials: P
authors.lastname: Polwichai
authors.forename: Surang
authors.initials: S
authors.lastname: Dejsirilert
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D016521:Electrophoresis, Gel, Pulsed-Field; D004926:Escherichia coli / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004927:Escherichia coli Infections / Q000453:epidemiology* / Q000382:microbiology; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D007710:Klebsiella Infections / Q000453:epidemiology* / Q000382:microbiology; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D010957:Plasmids; D016133:Polymerase Chain Reaction / Q000379:methods; D013785:Thailand / Q000453:epidemiology; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000096:biosynthesis / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; C456080:beta-lactamase CTX-M-14; C107198:beta-lactamase SHV-12; C430824:beta-lactamase SHV-27; D001618:beta-Lactamases