Performance of the β LACTA™ test for rapid detection of expanded-spectrum cephalosporin-non-susceptible Enterobacteriaceae

Abstract Objectives The aim of this study was to examine the performance of the chromogenic β LACTA™ test for the rapid detection of expanded-spectrum cephalosporin (ESC) non-susceptibility among Enterobacteriaceae in a region endemic for potent β-lactamases. Methods The β LACTA™ test was applied prospectively on 235 consecutive Enterobacteriaceae clinical isolates and 163 previously characterised ESC-non-susceptible Enterobacteriaceae producing a range of β-lactamases. Results The β LACTA™ test exhibited excellent sensitivity (96.1%) and specificity (98.5%) for the detection of ESC non-susceptibility in the 235 clinical isolates, which harboured mainly extended-spectrum β-lactamase (ESBL) and KPC- and NDM-type enzymes. Among the 163 challenged archived isolates, some false-negative or uninterpretable results were detected, mostly among ESC-non-susceptible isolates with AmpC/VIM/OXA-48-like enzymes. Conclusion β LACTA™ may be effectively applied in regions where ESC non-susceptibility among Enterobacteriaceae is mainly due to ESBL, KPC or NDM β-lactamases.