UTILITY OF HOSPITAL DATA TO CHARACTERIZE DIARRHOEAL BACTERIA AND THEIR SUSCEPTIBILITY TO GUAVA LEAF (Psidium guajava) EXTRACTS IN VIHIGA COUNTY, KENYA

Abstract

Studies have shown that diarrhoeal diseases are a leading toll on global morbidity and mortality especially among developing countries. Diarrhoeal cases are on the rise in Vihiga County, and residents have embraced the use of herbal medicine for diarrhoea treatment. General objectives of this study was to characterize the diarrhoeal bacteria based on hospital data and to determine their susceptibility to Psidium guajava leaf extracts in Vihiga County, Kenya. The specific objectives were; to determine the prevalence of pathogenic intestinal bacteria causing human diarrhoea, to assess the phytochemical components found in Psidium guajava leaf extracts, to determine the antimicrobial effects of Psidium guajava leaf extracts on Salmonella typhi, Escherichia coli and Shigella dysentriae, and to determine the minimum inhibitory concentration of Psidium guajava leaf extracts against the pure isolates. Primary data on diarrhoeal cases was collected at the sub-county hospitals, and secondary data on etiological agents for human bacterial diarrhoea obtained from each sub county hospital records MOH 706 from 2019-2022. Salmonella typhi with a prevalence of 37.1%, Escherichia coli at 15.4% and Shigella dysentriae at 10.6% were identified as major causative agents. Pure cultures of the identified bacteria were obtained from Friends Jumuia Hospital Kaimosi microbiology laboratory. Psidium guajava leaves were collected randomly from 70 farms across the county. Phytochemical compounds were extracted from Psidium guajava leaf extracts where flavonoids, tannins, saponins and terpenoids were found to be present. Extracts were prepared by weighing 100 g of dried Psidium guajava leaf powder, transferred into 500 mls conical flasks. 500 mls of 95% Ethanol, acetone and aqueous was poured into conical flasks with powder respectively and stirred. The mixtures were allowed to stand for 24 hours, decanted and filtered using Whitman’s filter paper, filtrates ware concentrated with 2 L series rotary evaporator at 79°C and refrigerated at 4°. On susceptibility testing against ethanol extract, Salmonella typhi had the highest zone of inhibition of 21.05 mm, Shigella dysentriae with 20.10 mm and Escherichia coli at 19.10 mm. On aqueous extracts, Escherichia coli had 11.25 mm, Salmonella typhi 8.15 mm and Shigella dysentriae 6.00 mm. On acetone, only Shigella dysentriae showed significant inhibition of 3.20 mm. Psidium guajava leaf extracts did not show any growth inhibition on Salmonella typhi and Shigella dysentriae in all concentrations of acetone extract. Salmonella typhi had the least MIC value of (2.16 mg/ml) at 100 mg/ml, Escherichia coli (7.16 mg/ml) at 100 mg/ml and Shigella dysentriae (3.0 mg/ml) at 75 mg/ml using ethanol extract. Escherichia coli recorded the highest MIC value of 11.34 mg/ml at 25 mg/ml using ethanol extracts. Data was analysed using ANOVA for variance analysis and then run through STATA (Version 16). All the Psidium guajava leaf extracts showed activities against the tested bacteria, with ethanol extracts showing the highest inhibition. The p-value from the study analysis was 0.001, which was smaller than the chosen significance level of 0.05 meaning that the difference in variation was significant. The study will address the community on the importance of diarrhoeal prevention and treatment.