Genetic characterization of Staphylococcus aureus isolated from Norway rats in Boston, Massachusetts.

BACKGROUND: Despite the importance of domesticated animals in the generation and transmission of antibiotic-resistant Staphylococcus aureus, the role of wild animals, specifically rodents, in the ecology of S. aureus remains unclear. We recovered and genotyped S. aureus isolates from wild Norway rats (Rattus norvegicus) in Boston, Massachusetts to examine genetic relationships between common human and animal S. aureus isolates in a large US metropolitan area. METHODS: We collected and necropsied 63 rats from June 2016 to June 2017. Nasal, foot pad, fur, and fecal swabs were collected. Staphylococcus aureus was isolated using culture-based methods and polymerase chain reaction confirmation. S. aureus isolates were spa typed, tested for antibiotic susceptibility, and whole genome sequenced. Assembled sequences were uploaded to the Comprehensive Antibiotic Resistance Database to identify antibiotic resistance elements. A phylogenetic tree was constructed using the neighbor-joining method with the maximum composite likelihood distance in MEGA7. RESULTS: We recovered 164 Gram-positive bacterial isolates from Norway rats. Nineteen isolates from eight individual rats were confirmed as S. aureus (prevalence: 12.9% (8/63)). All S. aureus isolates were methicillin-susceptible S. aureus (MSSA), pvl-negative, and resistant to penicillin. Two isolates displayed resistance to erythromycin. Four different S. aureus spa types were detected (t933, t10751, t18202, and t189). Thirteen unique antibiotic resistance elements were identified, and all isolates shared genes mepR, mgrA, arlR, and S. aureus norA. Phylogenetic analysis if the 19 S. aureus isolates revealed they were genetically similar to four clades of S. aureus with similar resistance gene profiles isolated from both human- and animal-derived S. aureus, as well as formed a distinct phylogenetic cluster composed only of rat isolates. CONCLUSIONS: Wild rodents may serve as a reservoir or vector of antibiotic resistance genes in the urban environment with relevance for human and animal health.

Comparative knowledge, attitudes, and practices regarding anthrax, brucellosis, and rabies in three districts of northern Tanzania.

BACKGROUND: Knowledge, attitudes, and practices (KAP) surveys regarding zoonotic diseases are crucial to understanding the extent of knowledge among citizens and for guiding health-related education programs. METHOD: Employing a structured questionnaire, we interviewed residents (n = 388) in three districts of northern Tanzania (Karatu n = 128, Monduli n = 114, Babati n = 146) to assess knowledge, attitudes and reported practices regarding three zoonotic diseases that occur in the region (anthrax, brucellosis, and rabies). We used generalized linear mixed effects models and multi-model inference to identify demographic correlates of knowledge. RESULTS: Proportional average district- and disease- specific knowledge scores ranged from 0.14-0.61. We found positive correlations between age and knowledge of symptoms, causes and treatments of anthrax (three districts), brucellosis (three districts), and rabies (one district). Gender, ethnic identity, formal education and ownership of livestock or dogs had variable effects on knowledge among the interviewed population. Risk perceptions regarding different diseases varied across districts and were positively correlated with knowledge of the specific diseases. Direct interactions with livestock and domestic dogs were reported to occur across all demographic groups, suggesting that most people living in rural settings of our study area are potentially exposed to zoonotic diseases. Behaviors which may favor transmission of specific pathogens (such as consumption of raw milk or meat) were occasionally reported and varied by district. Wildlife was generally regarded as negative or neutral with regard to overall veterinary and human health. CONCLUSION: The combination of variable knowledge about zoonotic diseases in the three districts, reported occurrence of practices that are conducive to pathogen transmission, and previously documented circulation of pathogens causing anthrax, brucellosis and rabies in our study system, call for health education programs embedded in a holistic One Health approach.