Biochemical and antibiotic resistance profile of Salmonella isolated from stool in N'Djamena, Chad: associated risk factors

Salmonella is responsible for two types of infections: foodborne gastroenteritis and typhoid and paratyphoid fevers. The objective of this study was to investigate the biochemical profile and resistance to antibiotics commonly used to treat the different Salmonella serotypes circulating in the city of N'Djamena. Isolation and identification of Salmonella in stool samples were performed at the laboratory of the National University Reference Hospital (CHU-RN) using standard clinical microbiology techniques. Of the 395 stool cultures performed, 17 (23.2%) Salmonella were isolated, among which the identified serotypes were: 5 (29.4%) Salmonella Typhi, 3 (17.6%) Salmonella Para Typhi A, 2 (11.7%) Salmonella Para Typhi B, 2 (11.7%) Salmonella Typhimurium, 2 (11.7%) Salmonella Enteritidis and 3 (17.6%) Salmonella arizonae respectively. Between the proportions of positive stool culture results in people with digestive disorders associated with symptoms (76.5%) (Group 1), and people with digestive disorders without signs of disease (23.5%) (Group 2), there is a significant difference in favor of group 1 (p = 0.001). The antibiotic efficacy test showed that 59% of Salmonella were resistant to aminopenicillins (ampicillin, amoxicillin), sulfamethoxazole-trimethoprim, nalidixic acid, and tetracycline. In contrast, 82% of Salmonella were susceptible to amoxicillin + clavulanic acid, ceftriaxone, ciprofloxacin, and imipenem. This study not only identified the serotypes of Salmonella, but also highlighted an effective antibiotic therapy for the prevention of Salmonella involved in diarrheal diseases circulating in the city of N'Djamena in Chad. Keywords: diarrhea, Salmonella, antibiotic, digestive troubles, N'Djamena, Chad.