Phenotypic Detection of Enterobacterales Strains Susceptible of Producing OXA-48 Carbapenemase

Abstract

Background: Nowadays, emergence of Carbapenemase-Producing Enterobacterales (CPE) throughout the world has become a public health problem, especially in countries with limited resources. In recent years, CPE of type OXA-48 (Ambler class D) have been identified in Dakar. The aim of this study was to evaluate the phenotypic detection of OXA-48 CPE using a temocillin disc (30 μg). Methodology: A retrospective study was carried out at Medical Biology Laboratory of Pasteur Institute in Dakar on Ertapenem-Resistant Enterobacterales (ERE) strains isolated from 2015 to 2017. These strains were then tested with a 30 μg temocillin disc. Any strain resistant to temocillin (inhibition diameter < 12 mm) was considered to be OXA-48 CPE. Confirmation of OXA-48 CPE was performed by PCR and sequencing. Results: Forty-one ERE isolated during the study period were tested, of which 34 (82.9%) were OXA-48 based on phenotypic detection using temocillin disc and confirmed by PCR (100%). OXA-48 CPE strains detected were composed of Klebsiella pneumoniae (n = 14; 41.2%), Enterobacter cloacae (n = 8; 23.5%), Escherichia coli (n = 7, 20.5%), Citrobacter freundii (n = 3; 8.8%), Cronobacter sakazakii (n = 1; 3%) and Morganella morganii (n = 1; 3%). Conclusion: Temocillin resistance has a good positive predictive value for detecting OXA-48 CPE by phenotypic method, confirmed by PCR. Temocillin is therefore a good marker for detection of OXA-48 CPE except Hafnia alvei .