title: Boronic acid disk tests for identification of extended-spectrum beta-lactamase production in clinical isolates of Enterobacteriaceae producing chromosomal AmpC beta-lactamases.
abstract: A study using boronic acid (BA) was designed to detect the extended-spectrum beta-lactamases (ESBLs) in Enterobacteriaceae producing chromosomal AmpC beta-lactamases. A total of 197 clinical isolates of Enterobacter spp. (n=100), Serratia marcescens (n=62) and Citrobacter freundii (n=35) were analysed. Genes encoding ESBLs were detected by polymerase chain reaction (PCR) amplification followed by direct sequencing of PCR products. The Clinical and Laboratory Standards Institute confirmatory test detected only 72.1% of the ESBL-producing isolates. When a > or =5mm increase in the zone diameter of either the cefotaxime/clavulanic acid and/or the ceftazidime/clavulanic acid disks tested in combination with BA versus cefotaxime and/or ceftazidime containing BA was considered to be a positive for ESBL, the method detected 60 (98.4%) of the 61 isolates that harboured ESBLs and showed no false-positive results for ESBL-non-producing isolates. In conclusion, the BA disk test is a highly sensitive and specific method for the detection of ESBLs in Enterobacteriaceae producing chromosomal AmpC beta-lactamases.
authors.affiliation: Department of Laboratory Medicine, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Seok Hoon
authors.initials: SH
authors.lastname: Jeong
authors.forename: Wonkeun
authors.initials: W
authors.lastname: Song
authors.forename: Min-Jeong
authors.initials: MJ
authors.lastname: Park
authors.forename: Jae-Seok
authors.initials: JS
authors.lastname: Kim
authors.forename: Han-Sung
authors.initials: HS
authors.lastname: Kim
authors.forename: Il Kwon
authors.initials: IK
authors.lastname: Bae
authors.forename: Kyu Man
authors.initials: KM
authors.lastname: Lee
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001897:Boronic Acids / Q000378:metabolism*; D016971:Citrobacter freundii / Q000201:enzymology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004754:Enterobacter / Q000201:enzymology*; D006801:Humans; D008826:Microbial Sensitivity Tests / Q000379:methods*; D016133:Polymerase Chain Reaction; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA; D012706:Serratia marcescens / Q000201:enzymology*; D001618:beta-Lactamases / Q000235:genetics / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D001897:Boronic Acids; D004269:DNA, Bacterial; C048795:AmpC beta-lactamases; D001618:beta-Lactamases