IDENTIFICATION AND ANTIBIOTIC SENSITIVITY OF MICROORGANISMS IN PRESUMPTIVE TYPHOID FEVER PATIENTS ATTENDING SELECTED HOSPITALS IN ONDO STATE, NIGERIA

Abstract

This study was designed to identify Salmonella typhi strains, other bacteria and fungi present in blood samples of presumptive typhoid fever patients attending selected hospitals in Ondo State, Nigeria. Biochemical tests and molecular biology techniques were employed to identify and compare the isolates. The antibiotic sensitivity profile and in-vitro interactions of the microorganisms were also established using disc and agar well diffusion as well as streak and pour plate methods. Questionnaires were administered on the influence of socio-demographic factors affecting the typhoid fever infection frequency in the study areas. Blood samples were collected from five hundred and twenty presumptive typhoid fever patients attending Don Bosco Clinic, Akure, State Specialists’ Hospital, Akure, and Federal Medical Centre, Owo, Ondo State. Conventional and molecular identification techniques employed revealed the same identities for Serratia marcescens and Pseudomonas aeruginosa. Salmonella typhi isolates 1 and 3, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Shigella flexneri traditionally identified were named molecularly as Enterobacter cloacae subsp. cloacae NCTC 9394, Enterococcus casseliflavus EC20, Achromobacter xylosoxidans NBRC 15126, Shigella flexneri 2002017 and Proteus mirabilis BB2000 respectively. The nucleotides of Salmonella typhi isolate 2 and Enterobacter aerogenes were considerably different from the nucleotides in the databank. Thus, they were molecularly identified as Bacterium species clone BAO 2 and Bacterium species clone BAO 14 respectively. The isolated fungi were Aspergillus repens, Aspergillus flavus, Aspergillus niger and Penicillium italicum. Amongst the co-existing microbes, Shigella flexneri and A. flavus co-existed more with the Enterobacter cloacae than other co-existing microbes. Shigella flexneri and A. flavus co-existed with sixteen (16) and two (2) Enterobacter cloacae isolates respectively. The constructed phylogenetic tree revealed that Bacterium species clone BAO 2, Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae subsp. cloacae NCTC 9394, Serratia marcescens, Bacterium species clone BAO 14, Achromobacter xylosoxidans and Proteus mirabilis belong to the first clade, Enterococcus casseliflavus is in the second clade while Shigella flexneri belongs to the third clade. The antibiotic sensitivity profile of the bacterial isolates showed that ofloxacin inhibited the growth of Enterobacter cloacae, Pseudomonas aeruginosa, Proteus mirabilis, Achromobacter xylosoxidans, Shigella flexneri and Serratia marcescens. Enterococcus casseliflavus was susceptible to tetracycline, chloramphenicol, cotrimoxazole, erythromycin and gentamicin but resistant to augumentin, streptomycin and cloxacillin. The growth of the fungal isolates was inhibited by ketoconazole, fluconazole and amphotericin B with Aspergillus niger having the highest zone of inhibition (15.00 ± 1.00mm) and A. repens showing the least inhibitory zone (11.00 ± 1.00mm). There was a positive interaction between Enterobacter cloacae and the microbial isolates. Certain socio-demographic factors (age, sex, marital status, occupation and domestic water source) were observed to have an influence on typhoid fever prevalence in the study areas.