Accelerated detection of extended-spectrum beta-lactamases in clinical isolates of Enterobacteriaceae.
A prospective study is carried out to evaluate the performance of a protocol for the accelerated detection of extended-spectrum beta-lactamases (ESBLs) in clinical isolates of Escherichia coli, Klebsiella pneumoniae and other Gram-negative bacteria. A modified double-disc test (MDDT) is incorporated in a Gram-negative template for routine susceptibility testing. The MDDT identified accurately ESBLs in all isolates subsequently confirmed as ESBL-producers by the standard Clinical Laboratory Standards Institute (CLSI) combined disc method. Of 1213 isolates tested, 98 (8%) were positive for ESBLs by MDDT and 95 (7.8%) were positive by the CLSI method. ESBLs were detected in 48 (7.8%) E. coli, 21 (8%) K. pneumoniae, 12 (5.8%) Proteus mirabilis, 13 (18.8%) Providencia stuartii and four (6.8%) Enterobacter cloacae isolates. Time required for ESBL detection by the MDDT method was one day. The protocol described provides a simple, rapid and low-cost method for early detection of ESBLs in Gram-negative bacteria.
Kader
A A
AA
Almana General Hospital, Department of Clinical Microbiology, PO. Box 1364, Al Khobar 31952, Saudi Arabia. aakader@doctor.com
Kamath
K A
KA
Dass
S M
SM
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002439:Cefotaxime / Q000494:pharmacology; D002442:Ceftazidime / Q000494:pharmacology; D052978:Disk Diffusion Antimicrobial Tests / Q000379:methods*; D004755:Enterobacteriaceae / Q000201:enzymology*; D004756:Enterobacteriaceae Infections / Q000175:diagnosis; D006801:Humans; D011446:Prospective Studies; D012529:Saudi Arabia; D018440:beta-Lactam Resistance; D001618:beta-Lactamases / Q000032:analysis*
D000900:Anti-Bacterial Agents; D002442:Ceftazidime; D001618:beta-Lactamases; D002439:Cefotaxime