Co-infection of salmonella typhi and soil-transmitted helminths and antimicrobial profiles in individuals attending Ukwala sub-county hospital, Kenya.

Abstract

ABSTRACT Gastrointestinal infections, such as soil-transmitted helminths (STHs) and Salmonella typhi infection, are a major cause of morbidity and mortality globally. In rural areas of Kenya, 9.1 million people are at risk of STHs infection with Western Kenya having the highest burden of both STH and S. typhi infection. Siaya County is more prone to S. typhi and STHs infection with Ukwala hospital records estimating the burden of infection at 30%. Given that STHs cause intestinal ulcers that may serve as entry points for enteric bacteria, there is need to determine the frequency of STHs and S. typhi among co-infected individuals and the demographic patterning of co-infection. Salmonella typhi isolates from Western Kenya exhibit widespread antibiotic resistance. It is known that co-infection weaken natural immunity thus compromising efficacy of the drugs in use. Whether co-occurrence of STHs and S. typhi affects efficacy of commonly used antibiotics, should therefore be investigated. This study was based in Ukwala Sub-County Hospital, Siaya County and aimed to investigate co-infection of S. typhi and STHs and antimicrobial profiles in individuals attending Ukwala Sub-County Hospital. The specific objectives were to determine: differences in frequencies of STHs in S. typhi positive and negative individuals; whether age and gender predict co-infection between S. typhi and STHs; and antimicrobial profiles of S. typhi isolates in individuals infected with S. typhi alone and individuals co-infected with S. typhi and STHs. Each stool sample cross-sectionally obtained from 325 individuals recommended for typhoid fever test was examined for the presence of eggs or larvae of Ascaris lumbricoides, Trichuris trichiura and Necator americanus by direct smear, and negative results were confirmed by formalin-ether concentration technique. Antimicrobial susceptibility test was based on disc-diffusion method on Mueller-Hinton agar. Salmonella typhi isolates were tested on four antibiotics commonly used to treat typhoid fever: ampicillin, tetracycline, chloramphenicol and ciprofloxacin. The frequency of individuals infected by STHs was higher among S. typhi negative than S. typhi positive individuals but there was no association between STHs and S. typhi infections (χ2 = 0.348, P> 0.05). Similarly, neither age nor gender significantly predicted occurrence of co-infection between S. typhi and STHs (logistic regression model, χ2 = 2.804, P> 0.05). Lastly, there was no difference in the antimicrobial resistance profiles of S. typhi isolates from individuals infected with S. typhi alone and individuals co-infected with S. typhi and STHs. The results suggest that infection by STHs does not appear to facilitate S. typhi infection. Alternatively, the level of STH infection in the population was very low, hence may have masked any patterns that may be salient under heavy disease burdens. Therefore, individuals recommended for S. typhi testing in Western Kenya, should also be tested for STHs. Furthermore, drugs of choice for the treatment of S. typhi as a single infection in Ukwala area should be used by the clinicians in treatment of individuals co-infected with S. typhi and STHs.