Heterogeneity and phylogenetic relationships of community-associated methicillin-sensitive/resistant Staphylococcus aureus isolates in healthy dogs, cats and their owners

Nasal Staphylococcus aureus and S. pseudintermedius carriage in healthy dogs and cats: a systematic review of their antibiotic resistance, virulence and genetic lineages of zoonotic relevance

The molecular ecology of Staphylococcus aureus, Staphylococcus pseudintermedius and their methicillin-resistant strains in healthy dogs and cats could serve as good models to understand the concept of bacterial zoonosis due to animal companionship. This study aims to provide insights into pooled prevalence, genetic lineages, virulence and antimicrobial resistance (AMR) among healthy dogs and cats. Original research and brief communication articles published from 2001 to 2021 that reported the nasal detection of S. aureus and S. pseudintermedius in healthy dogs and cats in the community, homes and outside veterinary clinics were examined and analysed. Forty-nine studies were eligible and included in this systematic review. The pooled prevalence of nasal carriage of S. aureus/methicillin-resistant S. aureus (MRSA) in healthy dogs and cats were 10.9% (95% CI: 10.1-11.9)/2.8% (95% CI: 2.4-3.2) and 3.2% (95% CI: 1.9-4.8)/0.5% (95% CI: 0.0-1.1), respectively. Conversely, the pooled prevalence of S. pseudintermedius/methicillin-resistant S. pseudintermedius (MRSP) in healthy dogs and cats were 18.3% (95% CI: 17.1-19.7)/3.1% (95% CI: 2.5-3.7) and 1.3% (95% CI: 0.6-2.4)/1.2% (95% CI: 0.6-2.3), respectively. Although highly diverse genetic lineages of S. aureus were detected in healthy dogs and cats, MSSA-CC1/CC5/CC22/CC45/CC121/CC398 and MRSA-CC5/CC93/CC22/CC30 were mostly reported in dogs; and MSSA-CC5/CC8/CC15/CC48 and MRSA-CC22/CC30/CC80 in cats. Of note, MSSA-CC398 isolates (spa-types t034 and t5883) were detected in dogs. Genetic lineages often associated with MSSP/MRSP were ST20/ST71, highlighting the frequent detection of the epidemic European MRSP-ST71 clone in dogs. S. aureus isolates carrying the luk-S/F-PV, tst, eta, etb and etd genes were seldomly detected in dogs, and luk-S/F-PV was the unique virulence factor reported in isolates of cats. S. pseudintermedius isolates harbouring the luk-S/F-I, seint and expA genes were frequently found, especially in dogs. High and diverse rates of AMR were noted, especially among MRSA/MRSP isolates. There is a need for additional studies on the molecular characterization of isolates from countries with under-studied nasal staphylococci isolates.

Whole genome sequencing of coagulase positive staphylococci from a dog-and-owner screening survey

BACKGROUND

Staphylococcus aureus and S. pseudintermedius are the two most common coagulase positive staphylococci (CPS). S. aureus is more prevalent among humans, whereas S. pseudintermedius is more commonly isolated from dogs, however, both can cause various community and hospital acquired diseases in humans.

METHODS

In the current study we screened 102 dogs and 84 owners in Hungary. We tested the antibiotic susceptibility of the strains and in order to get a better picture of the clonal relationship of the strains, we used pulsed-field gel electrophoresis. In addition, three pairs of isolates with identical PFGE patterns were whole genome sequenced, MLST and spa types were established.

RESULTS

Carriage rate of S. aureus was 23.8% in humans and 4.9% in dogs and two cases of co-carriage were found among dogs and owners. S. pseudintermedius carriage rate was 2.4% and 34.3%, respectively, with only one co-carriage. The isolates were generally rather susceptible to the tested antibiotics, but high tetracycline resistance of S. pseudintermedius strains was noted. The co-carried isolates shared almost the same resistance genes (including tet(K), bla(Z), norA, mepR, lmrS, fosB) and virulence gene pattern. Apart from the common staphylococcal enzymes and cytotoxins, we found enterotoxins and exfoliative toxins as well. The two S. aureus pairs belonged to ST45-t630, ST45-t671 and ST15-t084, ST15-t084, respectively. The co-carried S. pseudintermedius isolates shared the same housekeeping gene alleles determining a novel sequence type ST1685.

CONCLUSIONS

Based on the genomic data, dog-owner co-carried strains displayed only insignificant differences therefore provided evidence for potential human-to-dog and dog-to-human transmission.

Methicillin-sensitive and methicillin-resistant Staphylococcus aureus strains and their toxin genes in the nostrils of dogs and workers at an animal shelter

AIMS

Methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA, respectively) in the nostrils of dogs and workers at an animal shelter were cultured. Staphylococcal toxin genes were analysed to identify potential health concerns.

METHODS AND RESULTS

Samples were obtained from 441 dogs and 9 workers. The respective isolation rates of S. aureus and MRSA were 49·0% (216/441) and 1·6% (7/441) for shelter dogs and 44·4% (4/9) and 33·3% (3/9) for workers, respectively. Isolation of S. aureus in summer (61·9%) and in adult dogs (59·2%) were significantly higher than those in winter (35·8%) and in juvenile dogs (33·3%) (P < 0·001), respectively. The predominant enterotoxin genotypes and combination profiles of S. aureus were (sea, seb, seg, sei, sem, sen, seo, seu) and (sea, sea-seb, and seg-sei-sem-sen-seo-seu), respectively, and 20% of isolates carried food poisoning-associated enterotoxins. The se profiles in shelter dogs were different from those in general pet dogs and their owners. MRSA isolates were identified as SCCmec IV and VII, and they shared se combination profiles of (sec-seg-sei-sel-sem-sen-seo-seu) and (seb-sek-seq). MRSA in this shelter had similar microbiological characteristics as those reported in CA-MRSA ST59 in humans.

CONCLUSIONS

Human health-associated bacteria and food poisoning-related toxin genes were identified. Further evaluations of health concerns in animal shelters are necessary.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first study to focus on se prevalence and MRSA characteristics in an animal shelter in Taiwan. The MRSA characteristics determined in this study were similar to those of CA-MRSA strains isolated from communities in the past, indicating potential health risks in cities.

Prevalence and Risk Factors of Colonization with Staphylococcus aureus in Healthy Pet Cats Kept in the City Households

Staphylococcus aureus, especially methicillin-resistant S. aureus (MRSA), is a significant pathogen in both human medicine and veterinary medicine. The importance of pets as reservoirs of human infections is still poorly understood. This article provides detailed information of a cross-sectional study of a S. aureus colonization in clinically healthy indoor cats. The study systematically assessed a number of different anatomical locations for the S. aureus colonization and the influence of a range of potential risk factors on the value of the final S. aureus colonization rate. The incidence rates observed for cats with at least one site positive for S. aureus or MRSA were 17.5% and 6.63%, respectively. The following risk factors were identified: one or more owners working in the healthcare industry (human or veterinary); dogs being kept with the cat under investigation; treatment of the cat under investigation with antibiotics or chemotherapeutics during the previous year. In conclusion, this study revealed a higher prevalence of MRSA than what has previously been reported in healthy pets. A combination of anatomical locations from which the samples were collected had a major influence on the final value of the S. aureus colonization rate.

Is the Colonisation of Staphylococcus aureus in Pets Associated with Their Close Contact with Owners?

In human beings and animals, staphylococci constitute part of the normal microbial population. Staphylococcus aureus could be classified as an opportunistic pathogen because the bacteria are noted in clinically healthy individuals, but when the immune system becomes compromised, they can also cause a wide range of infections. The objective of this study was to test the hypothesis that cats who are in close contact with their owners are at the greatest risk of being colonised with S. aureus. Two groups of cats were investigated: single, pet (domestic) cats that do not have outdoor access; and a local population of feral cats living in urban areas. The prevalence of S. aureus in domestic cats was 19.17%, while it's prevalence in the feral cat population was only 8.3%; which was statistically significant. Analysis of antibiotic resistance, at the genotypic as well as phenotypic level, showed that S. aureus isolates from pet cats were more likely to harbour antibiotic resistant determinants. The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in households was 10.21%, while in feral cats it was only 1.4%. In conclusion, this study has revealed a correlation between close contact with humans and a higher risk of the cats being colonised with S. aureus and harbouring the antibiotic resistant determinants.

Molecular characterization of Staphylococcus aureus from nasal samples of healthy farm animals and pets in Tunisia

A total of 261 healthy farm and pet animals (75 cattle, 52 goats, 100 dogs, and 34 cats) from different regions of Tunisia were screened for Staphylococcus aureus nasal carriage. Molecular typing of isolates (by spa- and multilocus sequence-typing) was performed, and their antimicrobial resistance and virulence genotypes were determined by PCR and sequencing. S. aureus isolates were detected in 17 of 261 tested samples (6.5%). All S. aureus isolates recovered were methicillin-susceptible (MSSA), and one isolate/sample was further studied. Eight different spa types were detected (t189, t279, t582, t701, t1166, t1268, t1534, and t1773), and eight different sequence types were identified (ST6, ST15, ST45, ST133, ST188, ST700 [clonal complex CC130], ST2057, and a new ST2121). MSSA from pets (six isolates) showed resistance to (number of isolates, resistance gene): penicillin (six, blaZ), tetracycline (one, tet[M]), erythromycin one, erm[A]), streptomycin (one, ant[6]-Ia), and ciprofloxacin (one). All isolates from farm animals showed susceptibility to the tested antimicrobials, except for two penicillin-resistant isolates. Five S. aureus isolates from goats and cats harbored the lukF/lukS-PV genes, encoding the Panton-Valentine leukocidin, and six isolates from goats harbored the tst virulence gene. In addition, diverse combinations of enterotoxin genes were detected, including two variants of the egc cluster. Goats and cats could represent a reservoir of important toxin genes, with potential implications in animal and human health.

First report in South America of companion animal colonization by the USA1100 clone of community-acquired meticillin-resistant Staphylococcus aureus (ST30) and by the European clone of methicillin-resistant Staphylococcus pseudintermedius (ST71)

Background

Methicillin-resistant staphylococci can colonize and cause diseases in companion animals. Unfortunately, few molecular studies have been carried out in Brazil and other countries with the aim of characterizing these isolates. Consequently, little is known about the potential role of companion animals in transmitting these resistant bacteria to humans. In this work we searched for mecA gene among Staphylococcus isolates obtained from nasal microbiota of 130 healthy dogs and cats attended in a veterinary clinic located in the west region of Rio de Janeiro. The isolates recovered were identified to the species level and characterized using molecular tools.

Results

A community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) isolate related to USA1100 (Southwest Pacific clone) and susceptible to all non-β-lactams was detected in a cat (1.7%, 1/60). Another coagulase-positive isolate harboring mecA was recovered from a dog (1.4%, 1/70) and identified as Staphylococcus pseudintermedius (MRSP) related to the European clone (ST71). The two isolates of Staphylococcus conhii subsp. urealyticus (1.4%, 1/70 dogs and 1.7%, 1/60 cats), similarly to the MRSP isolate, also presented high-level multiresistance. The majority of the methicillin-resistant coagulase-negative staphylococci recovered were Staphylococcus saprophyticus (5.7%, 4/70 dogs and 6.7%, 4/60 cats) and all clustered into the same PFGE type.

Conclusions

This work demonstrates that mecA-harboring Staphylococcus isolates are common members of the nasal microbiota of the healthy companion animals studied (9.2%, 12/130 animals), including some high-level multiresistant isolates of S. pseudintermedius and S. conhii subsp. urealyticus. The detection, for the first time in South America, of USA1100-related CA-MRSA and of ST71 MRSP (European clone), colonizing companion animals, is of concern. Both S. pseudintermedius and S. aureus are important agents of infections for animals. The USA1100 CA-MRSA is a causative of severe and disseminated diseases in healthy children and adults. Additionally, MRSP is a nosocomial pathogen in veterinarian settings. It had already been demonstrated that the virulent ST71 MRSP is geographically spread over Europe and USA, with potential for zoonotic infections.

Incidence and characterisation of methicillin-resistant Staphylococcus aureus (MRSA) from nasal colonisation in participants attending a cattle veterinary conference in the UK

We sought to determine the prevalence of nasal colonisation with methicillin-resistant Staphylococcus aureus among cattle veterinarians in the UK. There was particular interest in examining the frequency of colonisation with MRSA harbouring mecC, as strains with this mecA homologue were originally identified in bovine milk and may represent a zoonotic risk to those in contact with dairy livestock. Three hundred and seven delegates at the British Cattle Veterinarian Association (BCVA) Congress 2011 in Southport, UK were screening for nasal colonisation with MRSA. Isolates were characterised by whole genome sequencing and antimicrobial susceptibility testing. Eight out of three hundred and seven delegates (2.6%) were positive for nasal colonisation with MRSA. All strains were positive for mecA and none possessed mecC. The time since a delegate's last visit to a farm was significantly shorter in the MRSA-positive group than in MRSA-negative counterparts. BCVA delegates have an increased risk of MRSA colonisation compared to the general population but their frequency of colonisation is lower than that reported from other types of veterinarian conference, and from that seen in human healthcare workers. The results indicate that recent visitation to a farm is a risk factor for MRSA colonisation and that mecC-MRSA are rare among BCVA delegates (<1% based on sample size). Contact with livestock, including dairy cattle, may still be a risk factor for human colonisation with mecC-MRSA but occurs at a rate below the lower limit of detection available in this study.

Transfer of multidrug-resistant bacteria between intermingled ecological niches: the interface between humans, animals and the environment

The use of antimicrobial agents has been claimed to be the driving force for the emergence and spread of microbial resistance. However, several studies have reported the presence of multidrug-resistant bacteria in populations exposed to low levels of antimicrobial drugs or even never exposed. For many pathogens, especially those organisms for which asymptomatic colonization typically precedes infection (e.g., Enterococcus spp. and Escherichia coli), the selective effects of antimicrobial use can only be understood if we considerer all biological and environmental pathways which enable these bacteria, and the genes they carry, to spread between different biomes. This ecological framework provides an essential perspective for formulating antimicrobial use policies, precisely because it encompasses the root causes of these problems rather than merely their consequences.