Isolation Serotyping and Molecular Characterization of Enteric Pathogens for Validation of “Peepoo” Sanitization along Handling Chain at Kibera, Nairobi Kenya

Abstract

An estimated 1.8 billion people in the world use water coming from fecally contaminated sources. This is as a result of 80% of the human generated wastewater ending up in rivers and other reusable water bodies before treatment. The hygienic balance is locally complicated by the fact that 57% of people in informal settlements have no access to basic sanitation, including latrines and toilets. This study sought to evaluate alternative toileting in the name of “Peepoo”, as single use personal toilet for human excreta sanitization and reuse as safe fertilizer, thus preventing dissemination of pathogens to the environment. A cross sectional study was conducted to sample 11 schools enrolled in the project working site in Kibera. Using standard microbiological methods, baseline faecal pathogen concentrations were determined as prevalences at the start of sanitisation and used to validate the “Peepoo” bag along handling chain. Specific primers were used for molecular characterization of isolated pathogens and detection of resistant genes. The prevalence of pathogenic bacteria (Salmonella enterica subspecies arizonae IIIa (0.34%), pathogenic Escherichia coli (7%), Campylobacter spp (18.3%), protozoa (Cryptosporidium spp (2.4%), Entamoeba histolytica (28%), soil transmitted helminth (Ascaris lumblicoides (20%) and Trichuris trichura (13%) eggs and gastrointestinal viruses (Rotavirus (0%) and Adenovirus (1.1%), were determined. There was marked difference in parasitism distribution among schools that was attributed to contamination of school compound with raw sewage. The identified bacteria and parasitic pathogens (Salmonella enterica, Escherichia coli, Campylobacter coli, Campylobacter jejuni, Campylobacter coli and Ascaris lumblicodes) in relation to pH, temperature and ammonia concentration were used to validate sanitation ability of the “Peepoo” bag along handling and reuse chain. Pathogenic Escherichia coli (69%) including EHEC (6.0%), EPEC (3.5%), ETEC (2.0%), DEAC (2.0%), EAEC (0.7%), EIEC (0.4%) and Campylobacter jejuni (92%), Campylobacter coli (88%), Campylobacter lari (76.9%) and Campylobacter spp (25%) were genetically identified and found to be resistant to 1st and 2nd generation antibiotics at different levels. Viral infection (Rotavirus and Adenovirus) was not identified as a health issue during the study period. Sequencing of PCR products from selected pathogenic Escherichia coli isolates confirmed their molecular identity. The results from this study demonstrated the ability of “Peepoo” bag to effectively inactivate pathogens found in human excreta when stored for 8 weeks at ambient temperature. This significantly reduced the risk of pathogens internalization by coriander grown in soil fertilized with human excreta. The peepoo bag should therefore be deliberately promoted as a method of human waste management in informal settlements and as alternative source of organic fertilizer. Mass deworming of children is also recommended after every three months in informal settlements.