The occurrence of Antibiotic-Resistant Escherichia coli in the Upper Citarum River and surrounding wastewater effluents

Wastewater has the potential to introduce antibiotic-resistant bacterial contamination into the adjacent river, posing environmental health risks to surrounding community. However, there is limited data on the bacterial resistance pattern in aquatic environments of developing countries. This study aimed to explore the hazard level of Antibiotic-Resistant Escherichia coli from effluents and river water based on the enumeration and resistance pattern towards thirteen antibiotics of varying potency. Escherichia coli enumeration was performed on samples collected from nine segments of the Upper Citarum River, and the effluents of two hospitals, six farms, five pharmaceutical companies, and two municipal treatment plants. Agar dilution on Chromocult (R) Coliform Agar ES was utilized to profile antibiotic susceptibility. The results show that Escherichia coli from farm wastewater has the highest average number (43.347 CFU/100mL) and the widest range of antibiotic resistance (up to eight type), followed by Escherichia coli from domestic, hospital and pharmaceutical effluent. Meropenem-resistant Escherichia coli is already detected in all effluent sources. Escherichia coli in the river water was resistant to thirteen types of antibiotics, and the load was increasing downstream. It is important to take immediate and effective measures to address bacterial resistance occurrence in the aquatic environments.