First report of a mecA-positive multidrug-resistant Staphylococcus pseudintermedius isolated from a dog in New Zealand

Carriage of Staphylococcus pseudintermedius by clinically normal dogs in Canterbury, New Zealand

AIMS

To investigate the frequency of carriage of methicillin-susceptible and methicillin-resistant Staphylococcus pseudintermedius (MRSP) in a population of clinically normal dogs within the Christchurch and wider Canterbury region, an area in which MRSP has been detected.

METHODS

Buccal and perianal swabs were collected from 126 clinically normal dogs presenting at veterinary clinics in the Christchurch/Canterbury region for de-sexing or routine vaccination. S. pseudintermedius was isolated by selective culture. Isolates were tested for susceptibility to 12 antimicrobials by disc diffusion.

RESULTS

S. pseudintermedius was isolated from 92/126 (73.0 (95% CI = 64.4-80.5)%) dogs, with 38/126 (30.2 (95% CI = 22.3-39.0)%) positive dogs carrying S. pseudintermedius at both sampled sites. More animals (78/126; 61.9; (95% CI: 52.8-70.4)%) had positive mouth cultures than positive perianal region cultures (52/126; 41.3 (95% CI: 32.6-50.4)%). No MRSP was isolated from clinically normal dogs. However, resistance to penicillin (106/130 (85.1%) swabs) and tetracycline (33/130 (25.4%) swabs) was seen.

CONCLUSIONS

The majority of the dogs in this sample were carriers of S. pseudintermedius. However none of these isolates were MRSP.

CLINICAL RELEVANCE

While most clinically normal dogs in the studied region are likely to be carriers of S. pseudintermedius, only a small proportion, if any, are likely to be carriers of MRSP. Antibiotic stewardship practices may be important to maintain low-level circulation of drug-resistant bacterial lineages.

Patterns of antimicrobial, multidrug and methicillin resistance among Staphylococcus spp. isolated from canine specimens submitted to a diagnostic laboratory in Tennessee, USA: a descriptive study

Background

Multidrug- and methicillin-resistant staphylococci are both veterinary and public health concerns due to their zoonotic potential. Therefore, the objective of this study was to investigate patterns of antimicrobial, multidrug, and methicillin resistance among four Staphylococcus spp. commonly isolated from canine clinical specimens submitted to the Clinical Bacteriology Laboratory at the University of Tennessee College of Veterinary Medicine (UTCVM).

Methods

Results of antimicrobial susceptibility testing and mecA polymerase chain reaction (PCR) for isolates of four common Staphylococcus spp. isolates were obtained from the Bacteriology Laboratory at the UTCVM between 01/01/2006 and 12/31/2017. Cochran-Armitage trend test was used to assess temporal trends of antimicrobial resistance (AMR), multidrug resistance (MDR), and methicillin resistance. Kappa test of agreement was used to assess agreement between the results of PCR and disk diffusion tests.

Results

Most of the 7805 isolates were S. pseudintermedius (6453 isolates), followed by S. coagulans (860), S. aureus (330), and S. schleiferi (162). Among S. pseudintermedius isolates, 45.5% were MDR, and 30.8% were methicillin-resistant (MRSP). There was a significant temporal increase in MRSP (p = 0.017). Chloramphenicol resistance increased among both MRSP and methicillin-susceptible (MSSP) isolates (p <  0.0001). Among S. aureus isolates, 40.9% were MDR, 37.4% were methicillin-resistant (MRSA), and the proportion of MRSA isolates increased significantly (p = 0.0480) over time. There was an increasing temporal trend in the proportion of MDR isolates among MSSP (p = 0.0022), but a decrease among MRSP (p <  0.0001) and MRSA (p = 0.0298). S. schleiferi had the highest percentage (56.9%) of methicillin-resistant isolates. Oxacillin disk diffusion was superior to cefoxitin for the detection of mecA-mediated resistance and had almost perfect agreement with mecA PCR assay for S. pseudintermedius (95.4% agreement, kappa (κ) = 0.904; p <  0.0001), S. coagulans (95.6%, κ = 0.913; p <  0.0001) and S. schleiferi (97.7%, κ = 0.945; p <  0.0001). However, cefoxitin disk diffusion was superior to oxacillin disk diffusion and had almost perfect agreement with mecA PCR assay for S. aureus (95.3%, κ = 0.834; p <  0.0001).

Conclusions

The levels of resistance and increasing temporal trends are concerning. These findings have implications for treatment decisions and public health due to the zoonotic potential of staphylococci. Continued surveillance and use of antibiograms to guide clinical decisions will be critical.

Assessment of listing and categorisation of animal diseases within the framework of the Animal Health Law (Regulation (EU) No 2016/429): antimicrobial-resistant Staphylococcus pseudintermedius in dogs and cats

Staphylococcus pseudintermedius (S. pseudintermedius) was identified among the most relevant antimicrobial-resistant (AMR) bacteria in the EU for dogs and cats in a previous scientific opinion. Thus, it has been assessed according to the criteria of the Animal Health Law (AHL), in particular criteria of Article 7 on disease profile and impacts, Article 5 on its eligibility to be listed, Annex IV for its categorisation according to disease prevention and control rules as in Article 9, and Article 8 for listing animal species related to the bacterium. The assessment has been performed following a methodology previously published. The outcome is the median of the probability ranges provided by the experts, which indicates whether each criterion is fulfilled (lower bound ≥ 66%) or not (upper bound ≤ 33%), or whether there is uncertainty about fulfilment. Reasoning points are reported for criteria with uncertain outcome. According to the assessment here performed, it is uncertain whether AMR S. pseudintermedius can be considered eligible to be listed for Union intervention according to Article 5 of the AHL (30-90% probability). According to the criteria in Annex IV, for the purpose of categorisation related to the level of prevention and control as in Article 9 of the AHL, the AHAW Panel concluded that the bacterium does not meet the criteria in Sections 1, 2 and 4 (Categories A, B and D; 0-1%, 1-10% and 10-33% probability of meeting the criteria, respectively) and the AHAW Panel is uncertain whether it meets the criteria in Sections 3 and 5 (Categories C and E, 5-66% and 30-90% probability of meeting the criteria, respectively). The animal species to be listed for AMR S. pseudintermedius according to Article 8 criteria are mostly species belonging to the families of Canidae and Felidae, such as dogs and cats.

Combining MALDI-TOF and genomics in the study of methicillin resistant and multidrug resistant Staphylococcus pseudintermedius in New Zealand

Staphylococcus pseudintermedius is an opportunistic and emerging zoonotic pathogen that primarily colonises the skin of dogs. Many common variants are methicillin resistant (MRSP) or multidrug resistant (MDR), and drug resistance is increasingly reported across the globe. In New Zealand, MRSP isolation remains rare in clinics. To pre-emptively inform diagnostic and antimicrobial stewardship practices, we examine isolates of S. pseudintermedius, MRSP and MDR-MRSP from New Zealand dogs using a combination of methodologies. Genetic and genomic data combined with antimicrobial susceptibility screening identify common drug-resistance profiles and their genetic determinants. We demonstrate that sensitive and specific species-level identification of S. pseudintermedius can be achieved using Bruker MALDI-TOF MS and, further, that this technique can be used to identify some common subtype variants, providing a level of categorical precision that falls somewhere between single-locus and multi-locus sequence typing. Comparative genomics analysis of global S. pseudintermedius data shows that MRSP moves frequently across the globe, but that horizontal gene transfer events resulting in the acquisition of the SCCmec cassette (responsible for beta-lactam antibiotic resistance) are infrequent. This suggests that biosecurity and surveillance in addition to antibiotic stewardship should play important roles in mitigating the risk of MRSP, especially in countries such as New Zealand where MRSP is still rare.