title: Modified double-disc test for detection of extended-spectrum beta-lactamases in Escherichia coli and Klebsiella pneumoniae.
abstract: This study evaluates the performance of a modified double-disc test (MDDT) for the detection of extended-spectrum beta-lactamases (ESBLs) in clinical isolates of Escherichia coli and Klebsiella pneumoniae. Ninety-six isolates of E. coli and 40 K. pneumoniae are studied for ESBL production by the National Committee for Clinical Laboratory Standards (NCCLS) combination disc tests and MDDT A total of 112 (82%) isolates (80 [83%] E. coli, 32 [80%] K. pneumoniae) were positive for ESBL by MDDT compared to 102 (75%; 72 [75%] E. coli and 30 [75%] K. pneumoniae) by the NCCLS method. In 10 (7.4%) isolates, ESBLs were detected only by MDDT Twenty-four (17.6%) isolates were negative for ESBL by both methods. The protocol described in this study provides a more sensitive approach than does the NCCLS method for ESBL detection in E. coli and K. pneumoniae.
authors.affiliation: Department of Clinical Microbiology, Almana General Hospital, P. O. Box 1364, Al Khobar 31952, Saudi Arabia. aakader@doctor.com
authors.forename: A A
authors.initials: AA
authors.lastname: Kader
authors.forename: K K
authors.initials: KK
authors.lastname: Angamuthu
authors.forename: K A
authors.initials: KA
authors.lastname: Kamath
authors.forename: M N
authors.initials: MN
authors.lastname: Zaman
mesh_terms: D000900:Anti-Bacterial Agents / Q000378:metabolism; D000077723:Cefepime; D002511:Cephalosporins / Q000378:metabolism; D019818:Clavulanic Acid / Q000378:metabolism; D024881:Drug Resistance, Bacterial; D004357:Drug Synergism; D004926:Escherichia coli / Q000201:enzymology*; D007711:Klebsiella pneumoniae / Q000201:enzymology*; D008826:Microbial Sensitivity Tests / Q000379:methods; D001618:beta-Lactamases / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D019818:Clavulanic Acid; D000077723:Cefepime; D001618:beta-Lactamases