Phenotypic characterization and antibiotic resistance of enterobacteria strains isolated from samples of patients in the towns of Moundou and Sarh in Chad

Today, enterobacteria constitute one of the most predominant causes of nosocomial and acquired infections in our communities. The bactericidal action of antibiotics on bacteria is used therapeutically, unfortunately the latter have started to develop resistances. Antibiotic resistance remains a major global public health issue, a serious problem in some of the world's poorest countries such as Chad. The objective of this study is to identify the strains of enterobacteria coming from samples of patients admitted to the Moundou and Sarh health centers, and to report their resistance profiles. A total of 278 samples consisting of urine (133) and stools (145) were collected in the laboratories of the two provincial hospitals of Sarh and Moundou between September and December 2021. The samples were processed and analyzed according to standard microbiology methods. The study of the sensitivity of different strains of enterobacteria with 14 antibiotic disks was evaluated by the disk diffusion method in agar medium. A total of 278 samples (urine, stool) including 111 strains of Enterobacteria, including 55 strains of E. coli, Enterobacter spp (n=17), klebsiella (n=11), Salmonella (n=9), Serratia ( n=7), Citrobacter (n=6) and Shigella (n=2) were isolated in the laboratory in the towns of Moundou and Sarh in Chad. The antibiogram carried out on all isolated strains of enterobacteria expressed a resistance ranging between 33.3% and 83.3% to 3rd generation cephalosporins, 30.3% and 50.0% to aminoglycosides. On the other hand, a strain of Salmonella is resistant to imipenem in Sarh. This study shows a high level of resistance acquired to different families of antibiotics by our bacterial strains studied. This resistance highlights the need to adapt therapeutic regimens to local epidemiology. Keywords : Characterization, Phenotype, Antibiotic resistance, Enterobacteria, Cities, Chad