The Silent Threat: Crossing the Species Barrier: Is Dog-Borne Infections Driving India’s Next Pandemic?

The Silent Threat: How Stray Dogs Accelerate Antimicrobial Resistance, Posing a Grave Global Health Crisis

Antimicrobial resistance (AMR) stands as an urgent global health and socioeconomic crisis, threatening to reverse many of the gains made in modern medicine. This phenomenon occurs when microorganisms like bacteria, parasites, viruses, or fungi develop the ability to survive in the presence of antimicrobials, rendering common treatments ineffective. While AMR is a complex problem driven by the misuse and overuse of antimicrobials across various sectors, including human medicine, agriculture, and livestock, emerging evidence points to stray animal populations, particularly dogs, as significant reservoirs and vectors in its spread. The interconnectedness of human, animal, and environmental health, often referred to as the One Health approach, is crucial to understanding and combating this escalating threat.

Stray Dogs: Potent Reservoirs of Drug-Resistant Pathogens

Stray dogs, due to their close contact with humans and the environment, serve as potent reservoirs of drug-resistant pathogens. Studies have isolated a variety of multidrug-resistant (MDR) bacteria from dog fecal samples collected from urban streets. These include:

• Multidrug-resistant Enterococci and methicillin-resistant Staphylococcus aureus (MRSA). A significant 65.7% of Enterococcus spp. isolated from dog feces exhibited high-level aminoglycoside resistance (HLAR). MRSA strains isolated from pets have been observed to resemble those found in hospital settings, suggesting potential transmission between animals and humans.

• Escherichia coli (EC) and Klebsiella pneumoniae (KP) strains that are multidrug-resistant and produce extended-spectrum β-lactamase (ESBL), AmpC β-lactamase, and metallo-β-lactamase (MBL), including those carrying blaNDM-1 and blaNDM-5 genes. Research indicates a considerably higher prevalence of multidrug resistance in E. colistrains from stray dogs compared to owned pets.

• Colistin-resistant E. coli carrying the mcr-1 gene, an antibiotic of last resort, have been identified in stray dog fecal samples.

• The drug-resistant yeast Candida auris, recognized by the World Health Organization (WHO) as a "critical priority" fungal pathogen due to its resistance to common antifungals, has been isolated from the ear canals of stray dogs. Researchers suggest these dogs could serve as transmission vehicles to other animals and humans.

Remarkably, these drug-resistant pathogens have been found in stray dogs even without a history or scope of prior antimicrobial therapy, highlighting the role of the environment in the spread of such pathogens and the further possibility of human infections.