Browsing by Author "Mwanza, Francis"

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Health risks associated with urban farming: Cryptosporidium and non-sorbitol fermenting Escherichia coli as indicator organisms in Dar Es Salaam, Tanzania
(Sokoine University of Agriculture, 2016) Mwanza, Francis
Cryptosporidium and enterohaemorrhagic (EHEC) Escherichia coli O157:H7 are two important pathogens in humans among other common representative zoonotic pathogens carried by animals especially cattle and are discharged through their faeces into the environment. With the increasing practice of urban farming, the risk of transmission of these pathogens to humans is increased. The study aimed at determining the public health risks associated with integrated urban farming using Non-Sorbitol Fermenting (NSF) E. coli and Cryptosporidium as indicator organisms in Dar es Salaam, Tanzania. A questionnaire survey was used to collect data on knowledge and practices associated with urban farming. Livestock manure, leafy vegetables and fish samples were collected to isolate and identify NSF E. coli and detect Cryptosporidium oocysts. Confirmed isolates on biochemical tests were subjected to antimicrobial resistance testing and genetic similarities of the isolates were determined using Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR). A total of 156 samples including 63 cattle faeces, 26 poultry faeces, 53 vegetables and 16 fish samples were tested for presence of Cryptosporidium and NSF E. coli. Out of 156 samples, 36 (23.1%) yielded NSF E. coli and 16 (10.3%) had Cryptosporidium oocysts. Five samples (3.2%) had both Cryptosporidium oocysts and NSF E. coli including four from vegetables and one from fish. Out of the 48 isolates of NSF E. coli tested for antimicrobial resistance to six antimicrobial agents, 25 (52.1%) were resistant to at least one antimicrobial agent and of these, 12 (48.0%) showed Multidrug Resistance. ERIC-PCR profiles of the 47 isolates from different sources showed genetic similarities (74.5% - 100%) with nine major clusters identified (I - IX) determined at 90% threshold level of similarity. These results showed potential health risks that would emanate from urban integrated farming and hence the need to monitor and improve husbandry practices used in urban farming.
Occurrence and determination of antimicrobial resistant escherichia coli isolates in fish and vegetables as indicator organism of faecal contamination in Dar es salaam, Tanzania
(Hindawi International Journal of Microbiology, 2021) Mwanza, Francis; Komba, Erick Vitus Gabriel; Kambarage, Dominic Mukama
Escherichia coli such as E. coli O157:H7, a non-sorbitol-fermenting (NSF) E. coli, is an essential human pathogen among other common zoonotic pathogens carried by animals especially cattle. ,ey are discharged through cattle faeces into the environment. With the increasing practice of urban farming, livestock manure is used as organic fertiliser in either fish ponds or vegetable gardens. ,is practice increases the risk of transmission of such pathogens to humans. ,is study aimed at determining the occurrence, antimicrobial resistance profiles, and genetic relatedness of E. coli isolates from manure, vegetables, and fish. Microbiological standard methods were used to isolate and identify E. coli isolates from manure, vegetable, and fish samples. Confirmed isolates on biochemical tests were tested for resistance against six antibiotics using the disc diffusion method. Enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) typing method was used to generate fingerprints and determine the genetic relatedness of the E. coli isolates. Of 156 samples including 89 manure, 53 vegetables, and 16 fish, 36 (23.1%) samples were positive for E. coli from where a total of 48 E. coli different isolates were recovered that were subjected to antimicrobial susceptibility testing and genetic relatedness. Of these isolates, 25 (52.1%) were resistant to at least one antimicrobial agent and 12 (48.0%) showed multidrug resistance. ERIC-PCR profiles of E. coli isolates from manure, vegetables, and fish showed genetic diversity with genetic relatedness ranging from 74.5% to 100%. Nine phylogenetic clusters (I–IX) determined at 90% threshold level of genetic relatedness were identified among the isolates. ,is study determined the occurrence, antimicrobial resistant patterns, and genetic diversity of antimicrobial-resistant E. coli isolates from different sources. ,is study showed the potential of microbial health risk to humans through contamination, and hence, it is necessary to monitor and improve husbandry practices in urban farming.