Beta-Lactamase bioassay: a simplified method to determine extended-spectrum beta-lactamases (ESBL) in enterobacteria
Silva-Sánchez, J.; Aguilar-Zacarías, C.
Archives of Medical Research 28(2): 285-287
1997
ISSN/ISBN: 0188-4409 PMID: 9204623 Document Number: 483938
With the simultaneous use of an isoelectric focusing gel (IEF) and a nitrocefin/cefotaxime bioassay, it is possible to identify the Extended-Spectrum beta-lactamases (ESBL) with precision. A mixture of soft agar and susceptible bacterial cells are layered over the gel following overnight incubation and areas of cell growth are detected where the antibiotic has been hydrolyzed by specific enzymes. This innovative method improves sensitivity and specificity for the identification of ESBLs in those enterobacteria strains producing more than one beta-lactamase and are resistant to third generation cephalosporines.