Water safety, antifungal‐resistant aflatoxigenic aspergillus flavus and other pathogenic fungi in a community hand‐dug wells

• Published in: Journal of applied microbiology Vol. 133; no. 2; pp. 673 - 682
• Main Authors: Shittu, Olufunke Bolatito, Iwaloye, Opeoluwa Favour, Oloyede, Adejare Rasak, Oni, Eniola Oluyemisi, Ajibola, Abiola Tosin, Arowosegbe, Adediwura Oladunni, Oluwasanya, Grace Olutope
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 01.08.2022
• Subjects: Aflatoxin B1; Aflatoxins; antifungal resistance; Aspergillus; Clotrimazole; Coliforms; Contamination; Correlation coefficient; Correlation coefficients; Densitometers; Deoxyribonucleic acid; DNA; Drinking; Drinking water; Dug wells; E coli; Fluconazole; Fungi; Fungicides; Gene sequencing; Griseofulvin; hand‐dug well water; Ketoconazole; Mycotoxins; Nystatin; Penicillium; Risk analysis; Rural areas; Rural communities; Safety; Water analysis; water safety; Water sampling; Water wells; Well water; hand-dug well water; aflatoxins; drinking water; fungi; antifungal resistance; water safety
• ISSN: 1364-5072; 1365-2672
• DOI: 10.1111/jam.15559

Aim To investigate hand‐dug well water used for drinking and domestic purposes in a rural community in Southwest Nigeria for water safety and fungal presence as well as to determine the antifungal resistance and aflatoxigenic potentials of isolated fungi. Methods and Results Water samples were analysed for risk of contamination, bacteriological and mycological parameters using a standard sanitary survey checklist and microbiological culturing. Isolates were identified and subjected to antifungal resistance profiling using the diffusion method for susceptibility testing of filamentous fungi. Multidrug‐resistant strains were confirmed with DNA barcoding identification. Fungal isolates were screened for aflatoxigenic potentials by culture methods and confirmed by densitometric analysis. From the 23 hand‐dug wells assessed, 56.52% had a high risk of contamination (ROC) score, nitrate >50 mg/L (73.9%), and the presence of total coliforms (100%), Escherichia coli (43.48%) and fungi (91.3%). Spearman rank correlation coefficient gave a positive and strong correlation between Total Fungi and Faecal Coliform (r = 0.701; p = 0.016; n = 23) at 0.05 significance level (2‐tailed). Aspergillus sp. (34%), Penicillium sp. (18%) and Rhizopus sp. (17%) were the most dominant fungal genera. Isolates were resistant to fluconazole (76.19%), ketoconazole (73.80%), clotrimazole (92.86%), griseofulvin (88.09%) and nystatin (100%). Penicillium and Aspergillus (50%) were positive for cultural mycotoxin screening. A strain of antifungal‐resistant A. flavus produced aflatoxin B1 (752 ppb) and B2 (15 ppb). Significance of the study The existence of antifungal‐resistant and aflatoxigenic fungi in water used for drinking and domestic purposes shows that filamentous fungi constitute greater threats than previously recognized and this call for a paradigm shift from the perceived safety of untreated hand‐dug well‐water.