Isolation of coagulase-positive staphylococci from bitches' colostrum and milk and genetic typing of methicillin-resistant Staphylococcus pseudintermedius strains

The Complex Diseases of Staphylococcus pseudintermedius in Canines: Where to Next?

Staphylococcus pseudintermedius is a pathogenic bacterium of concern within the veterinary sector and is involved in numerous infections in canines, including topical infections such as canine pyoderma and otitis externa, as well as systemic infections within the urinary, respiratory and reproductive tract. The high prevalence of methicillin-resistant Staphylococcus pseudintermedius (MRSP) within such infections is a growing concern. Therefore, it is crucial to understand the involvement of S. pseudintermedius in canine disease pathology to gain better insight into novel treatment avenues. Here, we review the literature focused on S. pseudintermedius infection in multiple anatomic locations in dogs and the role of MRSP in treatment outcomes at these niches. Multiple novel treatment avenues for MRSP have been pioneered in recent years and these are discussed with a specific focus on vaccines and phage therapy as potential therapeutic options. Whilst both undertakings are in their infancy, phage therapy is versatile and has shown high success in both animal and human medical use. It is clear that further research is required to combat the growing problems associated with MRSP in canines.

Lactation-related mammary gland pathologies-A neglected emergency in the bitch

Mastitis is a common reproductive disorder in bitches, reaching a prevalence of 0.71%. Mastitis has a wide range of forms, from asymptomatic to severe gangrenous mastitis that can lead to septic shock and death of the bitch and nurslings. However, most of the time it is overlooked, undiagnosed or mistreated. The present systematic review was performed to revise and summarize the existing knowledge related to this disorder, including diagnosis, treatment and prevention.

Breeder-reported patterns of antimicrobial use and point prevalence of methicillin-resistant Staphylococcus spp. among breeding bitches in the southwestern United States

Methicillin-resistant Staphylococcus pseudintermedius skin infections are an increasing concern in veterinary medicine, especially when found in juvenile dogs with no prior antimicrobial exposure. The objectives of this study were to assess the prevalence of methicillin-resistant staphylococci in breeding bitches and survey antimicrobial administration by their breeders. A total of 17 breeders and 54 bitches were included. Bitches were housed in diverse environments throughout the Phoenix, Arizona, USA metropolitan region. Nasal and oral gingival swabs were submitted for selective culture. Methicillin-resistant Staphylococcus aureus was not present, while methicillin-resistant Staphylococcus pseudintermedius was found in only 1/54 (1.9%) dogs. Survey results revealed that 16 bitches, which did not include the 1 MRSP-positive dog, had received antimicrobials within 6 months prior to sampling. Regardless of the low point prevalence identified, veterinarians and breeders should be cognizant of risks for bacterial resistance with the overuse of antimicrobials.

Prevalence and characterization of methicillin-resistant Staphylococcus pseudintermedius from symptomatic companion animals in Northern Italy: Clonal diversity and novel sequence types

The aim of this study was to assess the prevalence, the genotypic diversity, the antimicrobial resistance traits of canine and feline clinical methicillin-resistant Staphylococcus pseudintermedius (MRSP) isolates in a diagnostic laboratory in Italy during 2015-2016. All isolates were characterized by multilocus sequence typing (MLST), staphylococcal cassette chromosome (SCC)-mec typing and staphylococcal protein A (spa)-typing. The resistance profiles were assessed by antimicrobial susceptibility testing and confirmed genotypically by the detection of mecA gene and by microarray analyses. The prevalence of MRSP isolates was high (31.6%). All the strains were multidrug resistant and the most frequent clone was ST71-SCCmec type II-III. These results confirm a high prevalence of MRSP amongst clinical samples from pets in Italy. These isolates show multidrug resistance features that are of concern both in veterinary and human medicine for clinical and epidemiological reasons.

Occurrence and characterization of methicillin-resistant Staphylococcus pseudintermedius in successive parturitions of bitches and their puppies in two kennels in Italy

BACKGROUND

Multi-drug methicillin-resistant Staphylococcus pseudintermedius (MRSP) detection is rapidly increasing in microbial specimens from pets across Europe. MRSP has also been isolated from bitches and newborns in dog breeding kennels. This study assessed whether MRSP lineage differs between breeding kennels and is maintained over time. Post-partum bitches (at day 3 vaginal and day 3, 9 and 35 milk samples) and their litters (at day 3, 9 and 35 oral and abdominal skin samples) from two Italian breeding kennels (A and B) were sampled and MRSP was subsequently characterized via whole-genome sequencing and antibiotic susceptibility testing. The study was carried out from October 2014 to March 2016 and included successive parturitions from the same animals.

RESULTS

The analysis revealed different situations in both investigated kennels. In kennel A, circulating strains were from 7-locus sequence types ST688, ST258 and closely related isolates of ST71, which included most isolates. In kennel B, only a new isolate, ST772, was detected. In addition, most isolates from both kennels had multi-resistant antibiotic profiles. MRSP was only isolated from litters of MRSP-positive bitches, thus suggesting that bitch-litter transmission is likely.

CONCLUSIONS

Our data show that MRSP circulation can differ in different settings, that several clonal lineages can circulate together, and that vertical transmission appears common. MRSP colonization did not affect the health conditions of the bitches or of their litters.

Frequency, antimicrobial susceptibility and clonal distribution of methicillin-resistant Staphylococcus pseudintermedius in canine clinical samples submitted to a veterinary diagnostic laboratory in Italy: A 3-year retrospective investigation

In the last decade there has been a rapid global spread of methicillin-resistant Staphylococcus pseudintermedius (MRSP) clones displaying multidrug resistance in dogs. We investigated prevalence, antimicrobial susceptibility and clonal distribution of MRSP isolated from clinical canine samples between during 2011-2014. Following species identification by nuc PCR, MRSP were confirmed by the presence of mecA and characterized by antimicrobial susceptibility testing, Pulsed Field Gel Electrophoresis (PFGE), SCCmec typing, and Multi-Locus Sequence Typing (MLST) of a few isolates having distinct PFGE profiles. Both the MRSP isolation frequency in the 175 samples tested (12%) and the prevalence of methicillin resistance amongst the 63S. pseudintermedius isolates (33%) were high compared to a previous study in Italy. Sequence type (ST)71 carrying SCCmec type II-III, described as the epidemic European MRSP clone, accounted for approximately half of the isolates. The remaining isolates belonged to ST410-SCCmec type II-III, ST258-SCCmec type IV and other three clones associated with SCCmec type IV (ST261, ST290 and ST477). MRSP were consistently resistant to potentiated sulfonamides, and more frequently to clindamycin, ciprofloxacin and doxycycline than methicillin-susceptible isolates. Gentamicin was the only antibiotic showing good in vitro activity on all MRSP with 20 of the 21 isolates being susceptible. Results confirm a high prevalence of MRSP amongst clinical samples in Italy, revealing the emergence of new clones other than ST71, such as ST258, ST410, ST261, ST290 and ST477, here describe for the first time. Implementation of antimicrobial stewardship and surveillance programmes are required to prevent the emergence of new MRSP clones and reducing transmission in small animal practice.

Systematic Review on Global Epidemiology of Methicillin-Resistant Staphylococcus pseudintermedius: Inference of Population Structure from Multilocus Sequence Typing Data

Background and rationale: Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is a major cause of infections in dogs, also posing a zoonotic risk to humans. This systematic review aimed to determine the global epidemiology of MRSP and provide new insights into the population structure of this important veterinary pathogen.

Methodology: Web of Science was searched systematically for articles reporting data on multilocus sequence typing (MLST) of S. pseudintermedius isolates from dogs or other animal or human patients and carriers. Data from the eligible studies were then integrated with data from the MLST database for this species. Analysis of MLST data was performed with eBURST and ClonalFrame, and the proportion of MRSP isolates resistant to selected antimicrobial drugs was determined for the most predominant clonal complexes.

Results: Fifty-eight studies published over the last 10 years were included in the review. MRSP represented 76% of the 1428 isolates characterized by the current MLST scheme. The population of S. pseudintermedius was highly diverse and included five major MRSP clonal complexes (CCs). CC71, previously described as the epidemic European clone, is now widespread worldwide. In Europe, CC258, which is more frequently susceptible to enrofloxacin and aminoglycosides, and more frequently resistant to sulphonamides/trimethoprim than CC71, is increasingly reported in various countries. CC68, previously described as the epidemic North American clone, is frequently reported in this region but also in Europe, while CC45 (associated with chloramphenicol resistance) and CC112 are prevalent in Asia. It was estimated that clonal diversification in this species is primarily driven by homologous recombination (r/m = 7.52).

Conclusion: This study provides evidence that S. pseudintermedius has an epidemic population structure, in which five successful MRSP lineages with specific traits regarding antimicrobial resistance, genetic diversity and geographical distribution have emerged upon a weakly clonal background through acquisition of SCCmec and other mobile genetic elements.

High genotypic diversity among methicillin-resistant Staphylococcus pseudintermedius isolated from canine infections in Denmark

BACKGROUND

Methicillin-resistant Staphylococcus pseudintermedius (MRSP) has emerged globally in companion animals in the last decade. In Europe, the multidrug-resistant sequence type (ST)71 is widespread, but recently other clones have appeared. The objective of this study was to examine genotypic diversity and antimicrobial resistance of clinical MRSP isolates obtained from dogs, including dogs sampled on multiple occasions, in Denmark over a six-year period. For that purpose a total of 46 clinical MRSP isolates obtained from 36 dogs between 2009 and 2014 were subjected to antimicrobial susceptibility testing, multilocus-sequence typing (MLST) and SCCmec typing.

RESULTS

Twenty-three sequence types were identified with ST71, mostly associated with SCCmec II-III, as the most common occurring in 13 dogs. Among the remaining 33 isolates, 19 belonged to clonal complex (CC)258 comprising ST258-SCCmec IV and its single- and double-locus variants. These were susceptible to 4-7 of the 22 antibiotics tested, whereas CC71 isolates were susceptible to only 2-5 antibiotics. Clone-specific differences were especially pronounced for fluoroquinolones and aminoglycosides with most CC71 isolates being resistant and almost all CC258 isolates being susceptible. Sixteen of the 19 CC258 isolates had oxacillin MICs of 0.5 g/L, whereas MICs for CC71 isolates were consistently above 4 g/L. Four of five dogs representing multiple isolates had distinct STs on different sampling events.

CONCLUSIONS

The overall genotypic diversity of MRSP is high in Denmark indicating multiple acquisitions of SCCmec into distinct clones, and mutational evolution, which appears to be particularly rapid for certain ancestral clones such as ST258. ST71-SCCmec II-III is the most common MRSP lineage and is typically multidrug-resistant. CC258-SCCmec IV isolates, which emerged in Denmark since 2012, display susceptibility to a wider range of antimicrobials. The isolation of distinct STs in individual dogs over time suggests repeated exposure or short-term genetic evolution of MRSP clones within patients.