Molecular characterization of carbapenemase-encoding genes in carbapenem-resistant Pseudomonas aeruginosa isolated from clinical samples in Yaoundé, Cameroon.

The surge in Carbapenem resistant Pseudomonas aeruginosa strains has significantly narrowed treatment options, mainly driven by the production of carbapenemases disseminated through mobile genetic elements. Alarmingly, Cameroon has witnessed an increase in the spread of carbapenemases producing Pseudomonas aeruginosa isolates, highlighting a pressing public health issue. Thus, in this study we molecularly characterized carbapenemase-encoding genes in Carbapenem-resistant P. aeruginosa (CRPA) isolates recovered across six health facilities in Yaoundé, Cameroon. Carbapenem-resistant Pseudomonas aeruginosa isolates with different Carbapenem resistance profiles were selected and re-identified by culturing on Cetrimide and Nutrient Agar and carrying out biochemical identification using the API 20 NE system. Later on, the carbapenemases genes were evidenced via conventional polymerase chain reaction. Of the 217 isolates, 125 (representing 57.6%) were confirmed as Pseudomonas aeruginosa, with 31.2% (39/125) resistant to carbapenems. Among these, 48.7% (19/39) were resistant to Imipenem, and 51.3% (20/39) were resistant to Meropenem. Phenotypically, Carbapenemase production was observed in 46.2% (18/39) of CRPAs. The blaVIM gene was detected in 11 isolates (28.2%), representing the most frequently identified carbapenemase in our study. Specifically, we found that 6 isolates (15.4%) expressed blaNDM-1, 5 isolats (12.8%) presented blaDIM, 1 isolate (2 .6%) displayed blaKPC, while 2 isolates (5.1%) had blaOXA-50. Consistently, the majority of isolates (n = 22, or 56.4%) carried a single resistance gene. These results evidence the circulation of carbapenem resistant P. aeruginosa strains mediated by enzymatic resistance mechanisms in Yaoundé, Cameroon. Urgent need for innovative therapeutic strategies, antimicrobial stewardship and surveillance is imperative.