Occurrence of multidrug resistant Escherichia coli in groundwater of Brij region (Uttar Pradesh) and its public health implications

Aim: The study evaluates the microbial as well as physicochemical pollution of groundwater of Brij region of Uttar Pradesh, a major tourist destination in the country along with estimating the drug resistance evident in the isolated Escherichia coli.

Materials and methods: A total of 60 samples of groundwater were collected from six different sites and assessed for physicochemical (pH, color, taste, turbidity, total dissolved solids [TDS], total hardness [TH], chlorides, fluorides, nitrates, and iron) and microbiological parameters (standard plate count [SPC], most probable number test [MPN], E. coli).

Results: A majority of the samples were found to be out of the range for most of the parameters except iron. Particularly, high values of TDS (up to 9000 ppm), TH (1500 mg/L), chlorides (3250 mg/L), fluorides (2.5 mg/L), and nitrates (100.2 mg/L) were observed at most of the sites in the region highlighting the fact that groundwater of the area is not potable. Samples were turbid and salty to taste. High SPC values, up to 3500 colony-forming unit/ml and coliforms beyond BIS range were found in 40% samples suggesting gross microbial contamination. Only 2 sites (G3 and G5) had low MPN values. Overall 16 (26.67%) E. coli were isolated with 3 (18.75%) producing red colonies on conge red agar, hence supposed to be pathogenic. No E. coli O157:H7 was isolated. High antimicrobial resistance was observed against amoxicillin and erythromycin, whereas E. coli isolates were sensitive toward cefotaxime-clavulanic acid and imipenem. 12 isolates (75%) were multidrug resistant (MDR) with MDR index >20%, and 2 isolates (12.5%) were found to be extended spectrum beta-lactamases positive.

Conclusion: Groundwater is considered to be a safe option for potable water but it is obvious from the findings of this study that considerable physicochemical and microbial contamination is there in groundwater samples of Brij region. The occurrence of MDR E. coli in these waters is a matter of great public health concern.