Antibiotics susceptibility patterns and characterization of clinical Salmonella serotypes in Katsina State, Nigeria

Abstract

Serotyping characterization and antimicrobial susceptibility of Salmonella clinical isolates were examined for a period of 10-months to study the most frequently encountered serovars in salmonellosis and their antimicrobial susceptibility patterns. Seven hundred and twenty (720) samples of both stool and blood specimens were collected from out patients attending three hospitals in Katsina State, Nigeria. The samples were collected from patients diagnosed by clinicians with either pyrexia, gastroenteritis or both. Samples were cultured; isolates were identified and antibiotic susceptibility test was performed using standard procedures. The total number of 108 (15%) of the 720 samples collected yielded positive for Salmonella strains. Out of the 108 isolates, 61 (56.5%) were responsible for typhoidal salmonellosis, while 47(43.5%) were responsible for non-typhoidal salmonellosis. Of the 108 cases of salmonellosis, 91(84.3%) were from children and 17(15.7%) from adults. S. Typhi (40.7%) was the most frequently encountered, followed by S. Enteritidis (26.9%) and least encountered was S. Arizonae (2.8%). There was no significant difference in the serotypes isolated from each of the hospitals with respect to the type of salmonellosis caused with their p values >0.05. Of the total isolates, 94.2% were found to be resistant to ampicillin, 22.2% resistant to cefotaxime, 72.8% resistant to chloramphenicol, 31.8% resistant to co-trimoxazole and 4.9% resistant to nalidixic acid. However, resistance to ofloxacin and ciprofloxacin by the isolates were not found. Therefore, ofloxacin and ciprofloxacin remains the drug of choice for severe cases of salmonellosis, although caution should be exercised by clinicians in their prescriptions such that fluoroquinolones antibiotic therapy is used only in laboratory-proven cases of typhoid fever and Salmonella-associated bacteraemia to preserve its efficacy.