Phenotypic and genotypic characterization of Beta-lactamases in clinical isolates of Escherichia coli and Klebsiella pneumoniae from patients in Kinshasa, Democratic Republic of Congo

Background: The emergence and worldwide circulation of strains of beta-lactamase-producing Enterobacterales represent a major public health problem. The aim of this study was the characterization of extended spectrum beta-lactamase (ESBL) and carbapenemase-producing strains of Escherichia coli and Klebsiella pneumoniae resistant strains isolated in Kinshasa hospitals. Methods: Urine samples were collected from hospitalized and non-hospitalized patients. Bacteria were identified by using conventional biochemical tests and MALDI-TOF. Antibiotic susceptibility testing was performed by disk diffusion method. ESBL and carbapenemase phenotypes were screened using standard microbiological tests. ESBL-encoding genes were tested by multiplex end-point PCR assays and carbapenemase enzymes were identified by immunochromatography assay. Results: Out of 286 urines, 200 (69.9%) Gram negative bacteria were isolated, among them 70 (35.0 %) E. coli and 23 (11.5%) K. pneumoniae. ESBL were identified in 62.9 % (44/70) and in 52.2% (12/23) of E. coli and K. pneumoniae strains respectively. The rate of ESBL-producing Enterobacterales was 60.2% (56/93). Among ESBL producers, the blaCTX-M1 gene was identified in 88.6 % (39/44) isolates of E. coli and in 100% (12/12) isolates of K. pneumoniae. The bla-gene blaCTX-M-1 was identified in 91.2% (51/56) of all ESBL producers strains. Only 3.2% (3/93) of Enterobacterales strains produced the NDM enzyme. The Other genes encoding beta-lactamase were blaTEM (64.3 %), blaOXA-1/-30 (58.9 %), and blaSHV (39.3%). Conclusion: A high rate of ESBL-producing Enterobacterales was observed. The results of the study report the first description of metallo-β-lactamase NDM producing E. coli and K. pneumoniae strains from patients in Democratic Republic of Congo.