Characterization of TEM and CMY-2 beta-lactamases in Enterobacteriaceae strains isolated at the Brazzaville University and hospital center in Congo

Abstract

This study aimed to characterize the genes coding for ESBLs in TEM and CMY-2 Enterobacteriaceae. 65 strains of Enterobacteriaceae were isolated from 65 patients, of which 32.43% came from outpatients and 67.56% from hospitalized patients. The study was carried out over 6 months. The samples (urine, pus, and blood) were collected from hospitalized and external patients at the Brazzaville University Hospital. Strains were identified by API20E. An antibiogram was by diffusion in agar medium (MH) according to CA-SFM. The ESBL phenotype was detected by synergy. The plasmid cephalosporinase phenotype was determined by decreasing the diameter of inhibition around the cefoxitime disc in a strain resistant to ESBL inhibitors. Antibiotic resistance genes were characterized by PCR and sequencing. Sequences were assembled by Codon Code Aligner and compared by BlastX with Genbank, NCBI, and ARGANNOT. Phylogenetic gene trees were constructed using MEGA 7 software. 65 strains of Enterobacteriaceae were isolated from 65 patients, of which 32.43% came from outpatients and 67.56% from hospitalized patients. Except for imipenem, colistin; the amikacin and fosfomycin, tested antibiotics show high resistance to most of the beta-lactam, as well as resistance to very frequent aminoglycosides, sulfamides, tetracyclines, and Fluoroquinolones. PCR reveals that 97.29% possessed the TEM gene and 5.40% produced the CMY-2 gene. 64% of the isolates were isolated from urine samples, with a predominance of Enterobacter cloacae strains on ESBL production (75%). 60% of ESBL strains were isolated in the service of metabolic diseases. Sequencing of the amplification products revealed that the blaCTX-M1 strains were all TEM-1. Une consecvation des motifs SxxK en positions ABL 71 à 74 était observée pour l’alignement des sequences du groupe TEM. This study revealed the presence of the TEM and CMY-2 genes at disturbing frequencies. It proves the need to promote an infection prevention program with the regulation of antibiotic therapy in hospitals in Congo Brazzaville.