The Reliability of Using Vitek 2 Compact System to Detect Extended-Spectrum Beta-lactamase-producing Isolates in Escherichia coli and Klebsiella pneumoniae in Accra, Ghana

Abstract

Extended-spectrum beta-lactamases (ESBLs) are plasmid-mediated beta-lactamases that are capable of hydrolysing ?-lactams except carbapenems and cephamycins. The global increased prevalence of ESBL-producing bacteria creates an urgent need for laboratory diagnostic methods that will accurately and rapidly identify the presence of ESBL phenotypes in clinical isolates. The Vitek 2 System (bioMérieux, France) is a rapid automated microbiological system used for bacteria and yeast identification, antimicrobial susceptibility testing (AST), resistance mechanism detection and epidemiologic trending and reporting using its advanced expert system. This present work sought to determine the reliability of routinely using Vitek 2 System to accurately and rapidly detect ESBL-producing E. coli and K. pneumoniae in Accra. The ESBL phenotypes for 400 E. coli and K. pneumoniae isolates were determined using the Vitek 2 system and combined disc synergy method. The results were used to determine the sensitivity, specificity, negative predictive value and positive predictive value of the Vitek 2 ESBL test through comparative analysis with the combined disk synergy method which is the reference method recommended by CLSI. The findings of this work indicated that the sensitivity, specificity, positive predictive value and negative predictive value of Vitek 2 system was 98.5%, 98.9%, 99% and 98.5% respectively. Consequently, Vitek 2 system is a reliable semi-automated microbiology system which may be used for routine, accurate and rapid detection of ESBL strains in health facilities in Accra, Ghana.

Keywords: Vitek 2 Compact System, Extended spectrum beta-lactamase, bioMérieux, E. coli and K.  pneumonia