Characterization of Salmonella spp. from wastewater used for food production in Morogoro, Tanzania

Abstract

Wastewater use for crop irrigation and aquaculture is commonly practiced by communities situated close to wastewater treatment ponds. The objective of this study was to characterize Salmonella spp. and their antimicrobial susceptibility patterns among isolates from wastewater and Tilapia fish. A total of 123 Salmonella spp. isolates were isolated from 52 water and 21 fish intestinal samples. Genotyping of Salmonella spp. isolates was done by Pulsed-field Gel Electrophoresis (PFGE). Antimicrobial susceptibility testing was done by the minimal inhibitory concentration (MIC) technique. A total of 123 Salmonella spp. isolates represented 13 different serovars and 22 PFGE groups. Salmonella serovars showed resistance to 8 out of 14 antimicrobials; sulfamethaxazole (94%), streptomycin (61%), tetracycline (22%), ciprofloxacin and nalidixic acid (17%), trimethoprim (11%); gentamycin and chloramphenicol (6%). Salmonella Kentucky, S. Chandans, S. Durban and S. Kiambu showed multiple antimicrobial resistance to 7, 6 and 3 antimicrobials, respectively. This study has demonstrated that wastewater at the study sites is contaminated with Salmonella spp. which are resistant to common antimicrobials used for treatment of diseases in humans. Wastewater may, therefore, contaminate pristine surface water bodies and foodstuffs including fish and irrigated crops as well as food handlers.

Infection, colonization and shedding of Campylobacter and Salmonella in animals and their contribution to human disease: A review

“…Campylobacter and Salmonella are recurrently isolated from soil, water bodies, animal houses and effluents (Afema et al, ; Lyimo et al, ; Mhongole, Mdegela, Kusiluka, Forslund, & Dalsgaard, ; O'Mahony, Buckley, Bolton, Whyte, & Fanning, ). Free‐range or extensive systems of animal husbandry mostly practiced in rural resource‐poor settings, poor slurry management on animal farms and in slaughterhouses result in environmental bacterial contamination (Figure ; Afema et al, ).…”

Detection of Enteric Viruses and Bacterial Indicators in a Sewage Treatment Center and Shallow Water Bay

“…However, due to large quantity of bacteria in raw sewage, nonresponsive operations, or inadequate plant maintenance, pathogens can still be detected after final treatment [47]. This serious public health risk can be worsened by the ability of Salmonella to survive in the environment for long times, particularly in high salty conditions, and its ability to mutate and develop antibiotic resistance [48,49]. Salmonella isolated from effluent had been shown to have higher antibiotic resistance rates compared with those of influent [48].…”

Detection of <i>invA</i> Gene in <i>Salmonella</i> Limete Isolated from Wastewater Treatment Plant of University of Nigeria Nsukka, Nigeria

“…Isolation of Salmonella from wastewater is common, as is also the reuse of treated water for food production [1,2]. This practice is also carried out by the community living around the UNN wastewater treatment plants.…”

“…Salmonella species have been frequently isolated from wastewater, which are frequently reused in food production in different parts of the world [1,2]. Salmonella are known to cause severe disease symptoms that range from self-limiting diarrhoea to bacteraemia.…”