Characterization of Non-Typhoidal Salmonella Isolated from patients attending Agona Swedru Municipal Hospital

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APRIL, 2016
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Introduction: There is increasing occurance of salmonellosis with observed emergence of high level resistance to antimicrobial agents leading to the difficulty in treating infected patients with invasive infections worldwide. The study aims at determining the Salmonella species causing diarrhoea in Agona Swedru Municipal Hospital, as diarrhoea ranked the third common complaints in the hospital. Methods: Clinical samples comprising stool (n=380), blood (n=378) and urine (n=375) were cultured for Salmonella and other bacteria. The Salmonella isolates were serotyped based on Kauffmann and White scheme. Antimicrobial susceptibility testing was performed on all the isolates using the disc diffusion Kirby-Bauer method. Double-disk synergy test was used to test the isolates for Extended Spectrum -Lactamase production. The Salmonella isolates were fingerprinted by Pulsed-Field Gel Electrophoresis (PFGE) to determine their genetic relatedness. Results: Thirteen (13) Salmonellae were isolated from the diarrhoeal patients stool samples (n=380). Among the Salmonella serovars identified, Salmonella Enterica (69.2%; n=9/13) predominated, followed by Salmonella Choleraesuis (23.1%; n=3/13) and Salmonella Paratyphi B (7.7%; n=1/13). The most common pathogen isolated other than Salmonella was Escherichia coli (63.6%; n=21/33), followed by Staphylococcus aureus (18.2%; n=6/33), Citrobacter species (9.1%; n=3/33), Proteus mirabilis (6.1%; n=2/33) and Pseudomonas aeruginosa (3.0%; n=1/33). Salmonella isolates showed varied resistance to antimicrobials tested, with resistance proportions being Cotrimoxazole (9/13 (69.2%), Tetracycline (3/13, 23.1%), Amoxicillin (2/13, 15.4%), Ampicillin (2/13, 15.4). All the isolates were sensitive to Ceftriaxone, Ciprofloxacin, Amikacin, Gentamicin, Amoxicillin-Clavulanic acid, Chloramphenicol and Meropenem. None of the Salmonella isolates were multidrug resistant (MDR) and none produced Extended Spectrum -Lactamase. Extended Spectrum -Lactamase production was varied among other isolates. The Salmonella Choleraesuis isolates though were same species, were of different PFGE types. Conclusion: Prevalence of Salmonellae among patients attending Agona Swedru Municipal Hospital was 3.4%. Most of the Salmonellae were non-Typhoidal Salmonellae. Proportion of isolates resistant to antibiotics was low. There are possibly different S.Choleraesuis isolates circulating in Agona Swedru and its environs.
A thesis submitted to the School of Graduate Studies, Kwame Nkrumah University of Science and Technology in partial fulfillment of the requirements for the award of the Degree of Master of Philosophy in Clinical Microbiology