Molecular identification of biological contaminants in different drinking water resources of the Jazan region, Saudi Arabia

Seasonal variations and health risk assessment of microbial contaminations of groundwater in selected coastal communities of Ghana

This study investigated seasonal variations in microbial contaminations of groundwater and associated health risks in four coastal communities (Essiama, Winneba, Accra, and Keta) in Ghana. Membrane filtration methods, sanitary risk inspection, and quantitative microbial risk assessment were employed, respectively, to (i) quantify bacteriological quality, (ii) identify risks to contamination, and (iii) assess health risks associated with Escherichia coli in groundwater. Results showed 70.00%, 53.33%, 70.37% and 90.00% of groundwater sources in Essiama, Winneba, Accra, and Keta, respectively, were at intermediate risk, whereas 3.33%, 40.00%, 14.81%, and 3.33%, respectively, were at high risk. Very high-risk levels of contamination were recorded only in Accra. The presence of animal wastes within a 10 m radius of groundwater collection point, bad drainage systems, collection of spilt water in apron area, the use of ropes and buckets when fetching groundwater, and absence of aprons and well covers put more than 60.00% of the groundwater points in two or more locations at risk of contaminations. Assessment of bacteriological quality of groundwater indicated that mean total coliforms and E. coli ranged, respectively, between 123.40-501.30 and 30.98-141.90 CFU/100 ml for the communities; the highest microbial counts for dry and wet seasons occurred in Winneba and Keta, respectively. Seasonal variations in E. coli counts in Winneba and Accra were significantly higher in the dry season than in the wet season; Essiama and Keta showed no significant seasonal variations. Exposure to E. coli O157:H7 through drinking groundwater ranged between 5 and 23 cells per day. Although exposure to E. coli O157:H7 through bathing was less than 1 cell per day in all communities, residents were exposed to one E. coli, at least, every 62, 141, 237, and 282 days in Winneba, Accra, Keta, and Essiama, respectively. The risk of infection and illness for all communities was 1 for drinking, whereas that for bathing ranged from 0.57 to 0.98. The estimated Disability-Adjusted Life Years (DALY) exceeded the WHO-acceptable DALY. These findings show that groundwater resources in the selected coastal communities were prone to microbial contaminations, and this may be a setback to Sustainable Development Goals 6. Implications of the findings are discussed.

High fluoride resistance and virulence profile of environmental Pseudomonas isolated from water sources

In our previous study, all Pseudomonas strains THP6, THP41, and OHP5 were identified as fluoride-resistant bacteria isolated from Dindigul district, Tamilnadu, India. The selected strains exhibiting a high level of fluoride resistance was determined in Luria broth (LB) medium and LB agar plates. In a further effort, fluoride-resistant organisms were tested for hemolytic activity and showed β-hemolysis on blood agar plates. The virulence factors such as gyrB, toxA, algD and lasB, plcH, rhlC and biofilm response genes (pslA, pelA, ppyR) were detected by PCR analysis. The putative genus-specific and species-specific PCR also confirmed that the selected fluoride-resistant strains were belonging to Pseudomonas aeruginosa species. Fluoride-resistance gene crcB was amplified by gene-specific primers. The crcB gene was cloned in TA vector and transformed into E. coli DH5α. Comparative and blast analysis of THP6, THP41, and OHP5 strains crcB gene sequences were high homology with P. aeruginosa fluoride efflux transporter crcB and P. aeruginosa putative fluoride ion transporter crcB. The recombinants were efficiently growing in the NaF containing LB agar plates. The fluoride tolerance of these strains was also associated with resistance to multiple antibiotics. These results can lead to the use of the fluoride resistance gene of P. aeruginosa for the development of a biosensor for fluoride detection.