title: Prevalence and distribution of beta-lactamase coding genes in third-generation cephalosporin-resistant Enterobacteriaceae from bloodstream infections in Cambodia.
abstract: Resistance to third-generation cephalosporins in Gram-negative bacteria is emerging in Asia. We report the prevalence and distribution of extended-spectrum beta-lactamase (ESBL), AmpC beta-lactamase and carbapenemase-coding genes in cefotaxime-resistant Enterobacteriaceae isolates from bloodstream infections (BSI) in Cambodia. All Enterobacteriaceae isolated from BSI in adult patients at Sihanouk Hospital Centre of HOPE, Phnom Penh, Cambodia (2007-2010) were assessed. Antimicrobial susceptibility testing was carried out by disc diffusion and MicroScan according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Screening for ESBL, plasmidic AmpC and carbapenemase-coding genes was performed by multiplex polymerase chain reaction (PCR) sequencing assays. Identification of the ST131 clone was performed in all CTX-M-positive Escherichia coli, using PCR targeting the papB gene. Out of 183 Enterobacteriaceae, 91 (49.7 %) isolates (84 BSI episodes) were cefotaxime-resistant: E. coli (n = 68), Klebsiella pneumoniae (n = 17) and Enterobacter spp. (n = 6). Most episodes were community-acquired (66/84; 78.3 %). ESBLs were present in 89/91 (97.8 %) cefotaxime-resistant isolates: 86 (96.6 %) were CTX-M, mainly CTX-M-15 (n = 41) and CTX-M-14 (n = 21). CTX-M of group 1 were frequently associated with TEM and/or OXA-1/30 coding genes and with phenotypic combined resistance to ciprofloxacin, sulphamethoxazole-trimethoprim and gentamicin (39/50, 78.0 %). Plasmidic AmpC (CMY-2 and DHA-1 types) were found alone (n = 2) or in combination with ESBL (n = 4). Eighteen E. coli isolates were identified as B2-ST131-O25B: 11 (61.1 %) carried CTX-M-14. No carbapenemase-coding genes were detected. ESBL among Enterobacteriaceae from BSI in Cambodia is common, mainly associated with CTX-M-15 and CTX-M-14. These findings warrant urgent action for the containment of antibiotic resistance in Cambodia.
authors.affiliation: Department of Clinical Sciences, Institute of Tropical Medicine, Nationalestraat 155, 2000, Antwerp, Belgium, evlieghe@itg.be.
authors.forename: E R
authors.initials: ER
authors.lastname: Vlieghe
authors.forename: T-D
authors.initials: TD
authors.lastname: Huang
authors.forename: T
authors.initials: T
authors.lastname: Phe
authors.forename: P
authors.initials: P
authors.lastname: Bogaerts
authors.forename: C
authors.initials: C
authors.lastname: Berhin
authors.forename: B
authors.initials: B
authors.lastname: De Smet
authors.forename: W E
authors.initials: WE
authors.lastname: Peetermans
authors.forename: J A
authors.initials: JA
authors.lastname: Jacobs
authors.forename: Y
authors.initials: Y
authors.lastname: Glupczynski
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000453:epidemiology* / Q000382:microbiology; D002160:Cambodia / Q000453:epidemiology; D002439:Cefotaxime / Q000494:pharmacology; D002511:Cephalosporins / Q000494:pharmacology*; D004755:Enterobacteriaceae / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000453:epidemiology* / Q000382:microbiology; D004926:Escherichia coli; D005260:Female; D006801:Humans; D007711:Klebsiella pneumoniae; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D060885:Multiplex Polymerase Chain Reaction; D015995:Prevalence; D011446:Prospective Studies; D017422:Sequence Analysis, DNA; D055815:Young Adult; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D001618:beta-Lactamases; D002439:Cefotaxime