Phenotypic detection of Metallo-β-Lactamase in imipenem-resistant Pseudomonas aeruginosa and Stenotrophomonas maltophilia at Schiphra Hospital of Ouagadougou in Burkina Faso

Abstract

Background: Epidemic of carbapenemase-producing bacteria has become worldwide. Thus, during the last decade, the prevalence of carbapenem-resistant Enterobacteriaceae and non fermentative Gram-negative bacteria in human patients have increased. Carbapenemase-producing bacteria are usually multidrug resistant. Therefore, early recognition of carbapenemase producers is critical to prevent their spread. Objectives: The aim of this study was to contribute establishing the prevalence of isolates producing Metallo-β-Lactamase isolated from patients admitted to Schiphra Hospital of Ouagadougou. Methods: Susceptibility of bacteria to antimicrobial agents was evaluated by disc diffusion method using imipenem as screening antibiotic. The combination of imipenem-EDTA was used after detection the resistance to imipenem. Results: A total of 52 isolates resisting one of the third generation cephalosporins were collected. Five isolates showed an intermediary resistance to imipenem (9.61%). Two isolates were resistant to imipenem-EDTA (3.85%). The test of imipenem-EDTA was done to confirm to production of Metallo-β-Lactamase. The hydrolysis of bacterial extract by meropenem was confirmed by production with a kinetic activity at spectrophotometer V₀₌4.77x10^–5µM/min for Pseudomonas aeruginosa and V₀=1.183x10^-4 µM/min for Stenotrophomonas maltophilia. Conclusion: This study showed that bacterial resistances by production to metallo-β-lactamases are a reality in Burkina Faso.