Profile of predominant gram-negative pathogenic bacteria in River Sosiani and wastewater systems in Eldoret Town, Uasin Gishu County, Kenya

Gram-negative pathogenic bacteria play a significant role in spreading infections, with some strains exhibiting resistance to multiple antibiotics. Aquatic and wastewater systems, which receive effluents from various sources, contain pathogenic bacteria, chemicals, and antibiotic contaminants. This study investigated the bacterial load and antibiotic resistance profiles of gram-negative bacteria in water samples from wastewater systems and River Sosiani in Eldoret town, Kenya. Water samples were aseptically processed using standard microbiological techniques, followed by antibiotic susceptibility testing using the disc diffusion method. Data were coded and analyzed using Microsoft Excel and ANOVA. The highest bacterial count was detected at Kipkaren bridge (296) and the lowest at Kipkenyo boundary effluent (21). The study identified pathogenic gram-negative bacteria with varying frequencies: Escherichia coli (30.3%), Enterobacter aerogenes (20.9%), Klebsiella pneumoniae (10.3%), Salmonella enteritidis (8.7%), Citrobacter freundii (7.8%), Yersinia enterocolitica (5.6%), Proteus vulgaris (5.6%), Proteus mirabilis (5.1%), Pseudomonas aeruginosa (4.4%), and Klebsiella oxytoca (2.7%). Antibiotic susceptibility tests revealed that all isolates were susceptible to ciprofloxacin, doxycycline, gentamicin, and chloramphenicol, with high multi-antibiotic resistance indices recorded in E. coli (60%), E. aerogenes (33.3%), C. freundii (30%), K. oxytoca (30%), K. pneumoniae (25%), P. mirabilis (25%), P. vulgaris (16.7%), P. aeruginosa (12.5%), and Y. enterocolitica (12.5%) but not in S. enteritidis (0%). The study demonstrates rivers and wastewater systems as the critical reservoirs of pathogenic bacteria, exhibiting varying levels of multi-antibiotic resistance index. This poses threats of multi-drug resistant infections outbreak from the environment to public health, hence prompting the need for quick remedial action. IMPORTANCE The study highlights the critical role of wastewater and aquatic systems as reservoirs for pathogenic gram-negative bacteria, which play a key role in the spread of infections. The findings reveal an alarming presence of various antibiotic-resistant bacteria, with particularly high multi-antibiotic resistance index in several species to commonly used antibiotics. These findings demonstrate the urgent need for enhanced wastewater treatment practices and the regular monitoring of water sources to curb the spread of waterborne diseases and safeguard public health.