Treated wastewater used in fresh produce irrigation in Nsukka, Southeast Nigeria is a reservoir of enterotoxigenic and multidrug-resistant .

BACKGROUND

Occurrences of pathogens in environmental and irrigation waters, as well as the use of inadequately treated sewage for fresh produce constitute potential public health threats worldwide.

OBJECTIVE

To investigate the treated wastewater used in fresh produce irrigation in Nsuskka, Southeastern Nigeria, as a reservoir enterotoxigenic and multidrug-resistant .

METHODS

Treated wastewater (from the sewage treatment facility at Nsukka, Southeast Nigeria), soil and irrigated vegetable samples were collected and analyzed using standard procedures. isolated from the samples were screened for the presence of enterotoxigenic strain encoding lt gene and profiled for antibiotic resistance using the conventional PCR and standardized agar disk diffusion assays respectively.

RESULTS

Of the total presumptive 103 isolates, PCR detected A gene in 87 (84 %), of which 23 (26 %) harboured the encoding ETEC gene. Generally, imipenem, cefuroxime and norfloxacin proved to be most effective of all the antibiotics employed. Wastewater isolates were variously susceptible to ciprofloxacin (95 %), norfloxacin (95 %), cefuroxime (93 %), chloramphenicol (93 %), trimethoprim and tetracycline (88 %), soil isolates to streptomycin (75 %) and vegetable isolates to cefuroxime (90 %), norfloxacin (86 %), ciprofloxacin (81 %) and chloramphenicol. Contrariwise, high resistances observed to other antibiotics were in the order; ampicillin (95 %), penicillin (93 %), erythromycin (90 %) and clarithromycin (83 %) among wastewater isolates, ciprofloxacin and norfloxacin (75 %) in soil isolates; penicillin, vancomycin and erythromycin (98 %), rifampicin and clarithromycin (93 %), sulphamethoxazole (83 %), ampicillin (81 %), tetracycline and imipenem (76 %), trimethoprim (72 %) and amoxicillin (71 %) among vegetable isolates, with multidrug resistance patterns ranging from three to seventeen.

CONCLUSIONS

Our results reveal the treated wastewater as a reservoir of enterotoxigenic as well as multidrug resistance that may pose a health hazard for humans and animals when released to the natural environment. Hence, there is need to develop management strategies and ensure compliance in order to prevent water-borne diarrhoea caused by ETEC and reduce the menace of antibiotic resistance in the environment.