Plastic litter: A hidden reservoir for antibiotic-resistant pathogens in coastal ecosystems

Abstract

Plastic litter carrying pathogenic bacteria pose serious threats to the health of human and aquatic life. We enumerated the abundance of Escherichia coli and Vibrio species in different types of plastic litter (biomedical, food packages, sanitary, fishing material and miscellaneous) collected from the beaches of Agatti and Kavaratti in the Lakshadweep islands of India using quantitative real-time PCR. Further the antimicrobial resistance profile of E. coli and Vibrio species isolated from these samples were also tested. A very high number (more than three thousand gene copies per gram of plastic litter) of Escherichia coli, and Vibrio spp. were detected in the plastic litter. Vibrio spp. in the plastic litter were identified as V. harveyi, V. neocaledonicus, V. japonicus, V. parahaemolyticus and V. campbelli. More than sixty percentage of E. coli and Vibrio spp. isolated from all samples except the E. coli isolated from fishing gear of Kavaratti had multiple antibiotic resistance index of more than 0.25. Most of the bacteria were resistant towards ampicillin, erythromycin, and moxifloxacin, while least resistance was observed against gatifloxacin, gentamicin, imipenem, meropenem, norfloxacin and trimethoprim. These results indicate that plastic litter may act as a conduit for the attachment and transport of multiple antibiotic resistant pathogens, causing severe setbacks to the global efforts on attaining sustainable development goals 3 (health), 6 (clean water) and 14 (life under water). Therefore, strict implementation of plastic waste management rules, awareness campaigns for cleaning beaches and citizen science initiatives to monitor and remove plastics are proposed for protecting the beaches from the deleterious effects of mismanaged plastics.