Drug-resistant bacteria found in Vellore's wastewater, disposed antibiotics to be a breeding cause

As per a study, amoxicillin (used to treat Pneumonia, Bronchitis) is the most frequently detected antibiotic in the wastewater because of its high excretion rate.

The chronic presence of disposed antibiotics in wastewater is contributing to drug resistance in the environmental bacteria, a study says.

Sewage samples collected from four different hospital wastewater in Vellore (Tamil Nadu, India) showed development of resistance in the environmental bacteria. This developing microbial resistance is not directly associated with human interaction, however, it raises concerns around unhygienic disposal of medicines, particularly, antibiotics into the wastewaters by common practices such as flushing them down the toilet or throwing them into the drains.

According to the World Health Organization (WHO), antimicrobial resistance is one of the top global health threats and nearly one in three bacterial infections in India were resistant to antibiotics in 2025.

Wastewater as a breeding ground

Wastewater is a meeting place for pharmaceutical waste, environmental bacteria and diverse microbial communities. Excess of medicinal waste often ends up accumulating into the wastewater through hospital pipelines, industry and even residential areas. The natural bacteria present in this water persists and interacts with antibiotics and other microbes, leading to genetic adaptation and a developed immunity against these medicinal salts. This poses a major risk to public health as these microbes become immune to their presence.

As per the study, amoxicillin (used to treat pneumonia, bronchitis, skin diseases) is the most frequently detected antibiotic in the wastewater because of its high excretion rate. The sample bacteria collected from the hospital sewage showed a developed resistance against amoxicillin. The study also observed traces of multi-drug resistant bacteria in the sample.

How to safely dispose unused antibiotics

Antibiotics are drugs targeted to kill bacteria causing infections. These prescription medicines must not be saved for later use but if a person still have unused antibiotics at home, the following practices must be adopted to dispose them off:

• One can drop them at the nearest pharmacy or even hospitals for re-utilisation.

• Another way is to wrap them in a sealed bag and throw them into one’s household trash as dry waste. 

• Antibiotics must not be flushed off unless instructed on their packaging. 

Improper disposal of antibiotics can lead to accidental ingestion by humans or animals, and it also actively mutates the environmental bacteria present in the drains or wastewater. 

As per the WHO, the misuse and overuse of antimicrobials in humans, animals and plants is still the leading cause of antibiotic resistance in the country.