Phenotypic Characterization of Klebsiella Producing Extended-Spectrum β-Lactamases and Carbapenemases in Three Referral Hospitals in the City of Yaounde, Cameroon

Background: Antimicrobial resistance has become a major public health threat globally. The resistance mechanisms of Klebsiella include the production of extended-spectrum beta-lactamases (ESBLs) and carbapenemases, limiting the effectiveness of standard treatments. Objectives: The main objective of this study was to carry out the phenotypic characterization of β-lactam-resistant Klebsiella strains isolated from blood, pus and urine in three referral hospitals in the city of Yaounde. Methods: This was a cross-sectional study. Data collection was carried out over a one-year period from January to December 2023 in the bacteriology laboratories of three referral hospitals in Yaounde: Yaounde University Teaching Hospital (YUTH), Yaounde General Hospital, Yaounde Gynecological-Obstetric and Pediatric Hospital. Antimicrobial susceptibility testing by the disc diffusion method in accordance with the Antibiogram Committee of the French Society of Microbiology made the identification of the different resistance phenotypes possible. Results: Of the 264 clinical specimens analyzed, majority were from female patients, n = 135 (51.1%). The clinical specimens analyzed were urine, suppuration and blood (39.8%, 31.4% and 28.8% respectively). Klebsiella pneumoniae pneumoniae was the most frequently isolated subspecies (62.2%). The antibiotic susceptibility study showed an overall predominance of resistant strains with high rates of resistance to cefalexin, cefixime, ceftriaxone and cefotaxime (75.4%; 74.7%; 73.0% and 72.1% respectively). However, imipenem, meropenem, ceftazidime/avibactam and ertapenem were the most effective molecules against the Klebsiella species tested, with resistance rates of 10.6%, 14.3%, 21.7% and 30.4%, respectively. Phenotypic tests revealed the predominance of the following resistant phenotypes among the strains: extended-spectrum β-lactamase (42.4%), low-level/wild-type penicillinase (20.1%), derepressed penicillinase (3.0%), carbapenemases (33.7%) and high-level cephalosporinase (4.9%). Taking into consideration of the “screening carbapenemase-producing strains” algorithm, 89 isolates were suspected of producing carbapenemase, representing 33.7% of our isolates. Conclusion: Our findings demonstrate the circulation of strains with worrying resistance phenotypes, highlighting the urgent need for action by the Cameroonian health authorities.