Risk factors for antimicrobial resistance among Staphylococcus isolated from pets living with a patient diagnosed with methicillin-resistant Staphylococcus aureus infection.

It has been suggested that pets play a critical role in the maintenance of methicillin-resistant (MR) and multidrug-resistant (MDR) Staphylococcus spp. in the household. We examined risk factors for carriage of antimicrobial-resistant coagulase-positive staphylococci, with particular attention to Staphylococcus aureus and Staphylococcus pseudintermedius isolated from pets living in households of people diagnosed with methicillin-resistant S. aureus (MRSA) skin or soft-tissue infection. We analyzed data collected cross-sectionally from a study conducted in 2012 that evaluated the transmission of MRSA and other staphylococci from humans, their pets and the environment (Pets and Environmental Transmission of Staphylococci [PETS] study). We used unadjusted and adjusted stratified logistic regression analyses with household-clustered standard errors to evaluate the association between demographic, healthcare-related, contact-related and environmental risk factors and MDR Staphylococcus spp. isolated from dogs and cats. Staphylococcal isolates obtained from dogs (n = 63) and cats (n = 47) were included in these analyses. The use of oral or injectable antimicrobials by the pets during the prior year was the main risk factor of interest. Based on our results, 50% (12/24) of S. aureus, 3.3% (1/30) of S. pseudintermedius and 25% (14/56) of other coagulase-positive staphylococci (CPS) were determined to be MDR. S. aureus isolates were more likely to be MDR compared with S. pseudintermedius. We did not find a significant statistical association between the use of oral or injectable antimicrobials in the prior year and the presence of MDR bacteria. The results suggest that drivers of antimicrobial resistance in household staphylococci may vary by bacterial species, which could have implications for one health intervention strategies for staphylococci and inform the investigation of other reverse zoonoses, such as COVID-19.

Outbreak of a novel disease caused by Staphylococcus pseudintermedius in raccoon dogs (Nyctereutes procyonoides).

This study reports outbreak of a new disease caused by Staphylococcus pseudintermedius (S. pseudintermedius) in raccoon dogs. The disease occurred in a breeding farm of raccoon dogs in Guan County of Shandong Province in China in August of 2019. 47% (425/896) of the raccoon dogs showed some abnormal symptoms; 17.6% (75/425) of which had severe skin and soft tissue infections (SSTIs), dyspnoea and severe pathological lesions in lungs, livers, etc; and 4.2% (18/425) of which died within 4 weeks. The pathogen of the disease was identified as S. pseudintermedius by mass spectrometer detection, animal pathogenicity tests, microscopic examination and biochemical reaction tests. Its nucleotide homology of 16S rRNA gene was 100% with that of other published strains, and its genotype was between the American and Brazilian strains from other animals. The isolated S. pseudintermedius strain from the diseased raccoon dogs could cause ulceration and suppuration in the skins and severe pathological lesions not only in raccoon dogs, but also in mice; and it is confirmed as a methicillin-resistant S. pseudintermedius (MRSP) strain by the amplification of mecA gene; and 12 sensitive drugs were screened by drug sensitivity tests. Full attention should be paid to the great economic loss and the potential zoonotic risk caused by the S. pseudintermedius in raccoon dogs, and this study can provide a reference for the clinical diagnosis and treatment of this new disease.

Epidemiology of bacteria and viruses in the respiratory tract of humans and domestic pigs.

Bacteria and viruses were analysed in the upper respiratory tract of symptomatic pig farmers and their domestic pigs. Eighty six human nasal and 495 (50 pools) porcine snout swabs were collected in Schleswig-Holstein, Germany. Staphylococcus (S.) aureus (62.8%, 54/86), human rhino- and coronaviruses (HRV, 29.1%, 25/86; HCoV, 16.3%, 14/86) were frequently detected in humans, while Haemophilus parasuis (90.0%, 45/50), Mycoplasma hyorhinis (78.6%, 11/14), Enterovirus G (EV-G, 56.0%, 28/50) and S. aureus (36.0%, 18/50), respectively, were highly prevalent in pigs. The detection of S. aureus in human follow-up samples indicates a carrier status. The methicillin-resistant phenotype (MRSA) was identified in 33.3% (18/54) of nasal swabs and in one of 18 (5.6%) pooled snout swabs that were tested positive for S. aureus. Strains were indicative of the livestock-associated clonal complex CC398, with t011 being the most common staphylococcal protein A type. Enterobacterales and non-fermenters were frequently isolated from swabs. Their detection in follow-up samples suggests a carrier status. All were classified as being non-multiresistant. There was no example for cross-species transmission of viruses. In contrast, transmission of S. aureus through occupational contact to pigs seems possible. The study contributes to the 'One Health' approach.