Métodos alternativos para detecção de betalactamase de espectro estendido em Escherichia coli e Klebsiella pneumoniae

Abstract

Introduction: Antimicrobial resistance has increased apace in Brazil and worldwide in the last years, even though there is a great variety of resistance mechanisms and extended spectrum beta-lactamases (ESBL) is among the main ones. These enzymes are plasmid mediated, which causes resistance to some beta-lactam antimicrobials and are inhibited by compounds such as clavulanic acid, sulbactam and tazobactam. Objective: The objective of this study was to compare alternative methods to the standard ESBL detection technique recommended by the Clinical and Laboratory Standards Institute (CLSI). Material and method: Tests with 36 isolates (26 E. coli and 10 K. pneumoniae) were performed by means of CLSI disk diffusion method and alternative techniques designated as half disk (HD) and disk substitution (SD). Conclusion: Both methods yielded satisfactory results with higher sensitivity (90%) and lower costs in comparison with the reference one (CLSI disk diffusion method), which corroborates its use in ESBL investigation.