Assessment of five phenotypic tests for detection of methicillin-resistant staphylococci in Cotonou, Benin

Abstract

The study aimed at assessing performance and cost of phenotypic tests for detecting methicillin resistance in Staphylococcus spp. isolates in Cotonou, Benin. Isolates consecutively collected from various specimens from four medical laboratories in Cotonou from December 2012 to April 2013 were included in the study. The isolates were subjected to five phenotypic tests: disk diffusion tests with cefoxitin (Cefox) and moxalactam (Moxa) on Mueller Hinton agar incubated at 37°C, oxacillin on Mueller Hinton agar incubated at 30°C (Oxa30), oxacillin on salt Mueller Hinton agar incubated at 37°C (Oxa37) and agglutination test for PBP2a detection (TPBP 2a). Results were compared with polymerase chain reaction (PCR) of mecA gene which was used as the gold standard. In addition, cost per reagent of each phenotypic test was assessed. Considering the general agreement with PCR, Cefox and Moxa were the best tests in S. aureus while in non-aureus Staphylococcus isolates, TPBP 2a was the best test but its cost was 20 times higher than that of disk diffusion tests.