Water Contamination by Commonly Used Antimicrobials Around Tertiary Care Centres in South Kerala, India: An Environmental Risk and Antimicrobial Resistance Perspective

Background- Water contamination caused by antimicrobials in water sources and its consequences such as environmental risk and antimicrobial resistance is less explored in Kerala, India.

Objectives- The study aims to find the concentration of antimicrobials in water sources and to analyze the environmental risk and antimicrobial resistance risk due to the prevailing drug concentration in water sources.

Methods- Five commonly used antimicrobials in a tertiary care centre were identified from purchase records- Azithromycin, Cefotaxime, Ciprofloxacin, Meropenem and Metronidazole Thirty-one samples of surface and ground water including drinking water sources were identified. Water from these sources were preconditioned and passed through Liquid Chromatography Mass Spectrometry instrument to quantify the concentrations of antimicrobials.

Results- Measured environmental concentration (MEC) were- Azithromycin (2.93 µg/L), Cefotaxime (3.10 µg/L), Ciprofloxacin (0.80µg/L), Meropenem (3.42 µg/L and Metronidazole (2.35 µg/L). Using Predicted no effect concentration-environment (PNEC-ENV), environmental risk (R_ENV) calculated for Azithromycin (97.67), Cefotaxime (25.83), Ciprofloxacin (1.76), Meropenem (2.28) and Metronidazole (78.0) are above the value of 1, which shows that they are at a level to cause high environmental risk. Highest MECs of the five antibiotics against PNEC-MIC (minimum inhibitory concentration) shows that risk of antimicrobial selection pressure (R_AMR) is above 1.

Conclusion- The concentration of antimicrobials in the water sources are in the range of posing environmental risk and for selection of antimicrobial resistant organisms in the environment. Modification of policy regulations, proper and safe disposal of drugs and water purification methods have to be done to prevent pharmaceuticals from entering the water sources and to remove those present in them.