DRUG-RESISTANT BACTERIUM SPREADING BETWEEN PETS AND HUMANS, STUDY FINDS
Chinese scientists have identified a pathway for drug-resistant Acinetobacter baumannii to spread from pets to humans, according to research published in Applied and Environmental Microbiology. The bacterium, classified as "Priority 1" by the World Health Organisation owing to its resistance to antibiotics including last-resort treatments, causes conditions such as meningitis and pneumonia in humans and similar infections in companion animals. Researchers from Nanjing Agricultural University, Wuhu Institute of Technology, and Nanjing University of Chinese Medicine examined genetic data from over 500 A. baumannii samples collected from animals across 17 countries spanning 33 species.
The team analysed samples from white storks in Poland, cats, dogs, and horses treated in veterinary clinics across Europe, alongside thousands of human clinical samples from the same regions. Scientists identified two distinct groups of the bacterium: a low-resistance group dominated by livestock, poultry, and wildlife, and a high antimicrobial resistance group dominated by horses, cats, and dogs. Genome similarity between strains found in humans and in companion animals was approximately 99 per cent in most cases, with some exceeding 99.5 per cent. Several A. baumannii lineages known as "international clones" — the same strains behind hospital outbreaks worldwide — appeared repeatedly in companion animals, with one clone designated ST25 identified across nine animal species.
The findings suggest that companion animals rather than livestock may represent the primary reservoir for antibiotic-resistant A. baumannii transmission to human populations. The research indicates that A. baumannii from cats, dogs, and horses is genetically nearly indistinguishable from hospital-acquired strains infecting humans in nearby regions. The study establishes zoonotic transmission as a documented pathway for this Priority 1 pathogen, though the researchers did not specify recommendations for reducing transmission risk.