Antibiotikaresistens i kjæledyr og deres hjemmemiljø : fra et Én helse perspektiv

Antimicrobial resistance (AMR) is disseminated in all three sectors comprised by the One Health concept: Humans, animals, and environment. Yet, much is unknown regarding the reservoirs for antimicrobial resistance in our immediate surroundings, namely our companion animals and home environments. Therefore, this thesis investigates the companion animals’ and home environments’ roles as reservoirs for antimicrobial resistance genes (ARGs), methicillin-resistant staphylococci (MRS), and mammaliicocci (MRM). Further does the thesis investigate the transmission potential of clinical methicillin-resistant staphylococci from infected pets to their owners and surrounding environments. Fecal samples from healthy dogs and owners were analyzed for the presence of ARGs. Humans, companion animals, and home environments from different types of households (infected pet, healthy pet, and no-pet households) were screened for MRS and MRM. Bacterial isolates were further examined phenotypically and genotypically to determine their species identity, sequence types, SCCmec and to characterize their resistance and virulence genes. By analyzing the fecal samples, we documented high rates of aminoglycoside resistance genes and mecA, the gene responsible for methicillin resistance, in the canine fecal samples. At the group level, dogs and owners carried many of the same resistance genes. However, only a moderate proportion of the ARGs were simultaneously present in dogs and owners from the same household, indicating a low level of transmission. Interestingly, older dogs had more fecal ARGs in common with their owners. Furthermore, we have documented that methicillin-resistant coagulase-negative staphylococci (MRCoNS) and MRM were close to ubiquitous in the home environments, regardless of type of household or human/pet carriage of MRCoNS/MRM. In addition to harboring the mecA gene, the majority of isolates were multidrug-resistant, expressing resistance to three or more classes of antimicrobials. Despite the vast presence of MRCoNS and MRM in their home environments, none of the healthy companion animals tested positive for methicillin-resistant bacteria. In contrast, several cases of human and infected-pet carriage of MRCoNS were documented, of which some isolates of the same sequence type and resistance profiles were present in the home environment. Clinical MRS were primarily recovered from the infected dogs and locations in direct contact with dogs. Nonetheless, in half of the households, clinical MRS were present in locations out of reach for the dogs, indicating an indirect transmission. In terms of zoonotic transmission, clinical MRS were recovered from the noses of two owners. In addition, several cases of owners testing positive for methicillin-susceptible Staphylococcus pseudintermedius (MSSP) was documented. In all the cases, MSSP was not recovered the following day, indicating that the human carriership was temporary. The resilience of clinical MRS was demonstrated by their presence in the home environment, despite infection recovery, cleaning measures, and the euthanization of one dog. In summary, the findings in this thesis have illuminated our immediate surroundings as reservoirs for AMR. The study contributes to a broader knowledge base for studies and risk assessments regarding AMR transmission in the interface between humans, companion animals, and home environment.Antibiotikaresistens er utbredt i alle sektorer innebefattet av Én Helse-begrepet: Mennesker, dyr og miljø. Allikevel er det mye man ikke vet om reservoarer for antibiotikaresistens i våre nærmeste omgivelser. Denne avhandlingen undersøker derfor kjæledyrs og hjemmemiljøets rolle som reservoar for antibiotikaresistensgener, meticillinresistente stafylokokker (MRS) og mammalikokker (MRM). I tillegg fokuserer avhandlingen på overføringspotensialet til MRS fra kjæledyr til eiere og deres omgivelser. Avføringsprøver fra friske kjæledyr og eiere har blitt undersøkt for antibiotikaresistensgener. I tillegg har mennesker, kjæledyr og hjemmemiljøet fra ulike typer husholdninger blitt screenet for meticillinresistente stafylokokker og mammalikokker. Videre ble bakterieisolater fenotypisk og genotypisk analysert for identifisering av art, sekvenstype, SCCmec-kassett, samt virulens- og resistensgener. Gjennom analysen av hundeavføringsprøvene avdekket vi en høy frekvens av aminoglykosidresistensgener og mecA, genet som gir meticillinresistens. Hunder og eiere bar på mange av de samme resistensgenene på gruppenivå, men innad i husholdningene var det kun en moderat andel av resistensgener til felles, noe som tyder på et lavt overføringsnivå mellom hund og menneske. Interessant nok, fant vi at eldre hunder hadde flere resistensgener til felles med eierne sine enn yngre hunder. Studien har videre dokumentert at meticillinresistente koagulasenegative stafylokokker (MRKNS) og MRM nærmest er ubikvitære i hjemmemiljøer uavhengig av type husholdning og bærerskapsstatus hos menneske/kjæledyr. Flertallet av miljøisolatene var multiresistente. Til tross for den høye forekomsten av MRKNS og MRM i hjemmemiljøet var det ingen av de friske kjæledyrene som testet positivt for MRKNS eller MRM. I stedet avdekket vi flere humane tilfeller av bærerskap, samt flere hunder som i tillegg til å ha en pågående infeksjon med meticillinresistente Staphylococcus pseudintermedius bar på MRKNS. Kliniske MRS ble hovedsakelig funnet på hundene med pågående infeksjon og på steder disse hundene hadde direkte kontakt med. Vi fant også kliniske MRS på steder utenfor rekkevidde for hundene, noe som tyder på at det har forekommet indirekte overføring av bakteriene innad i husholdningen. Når det gjelder zoonotisk overføring, avdekket vi to tilfeller av humant bærerskap av kliniske MRS. I tillegg registrerte vi flere tilfeller der eiere testet positivt for meticillinsensitive S. pseudintermedius (MSSP). Vi kunne imidlertid ikke påvise noen tilfeller av humant bærerskap av MSSP over flere dager på rad, noe som indikerer at bærerskapet kun var midlertidig. De kliniske MRSenes motstandsdyktighet manifesterte seg ved at de kunne påvises i hjemmemiljøet flere uker uten kliniske symptomer eller tilstedeværelse av hund. Kort oppsummert har studien belyst våre nærmeste omgivelsers rolle som reservoar for antibiotikaresistens. Funnene i studien bidrar til et bedre kunnskapsgrunnlag for utredning av risiko for overføring av resistens i krysspunktet mellom menneske, kjæledyr og hjemmemiljø.NORM- Norsk overvåkningssystem for antibiotikaresistens hos mikrobe

Antimicrobial resistance—Do we share more than companionship with our dogs?

Aims To investigate and compare antimicrobial resistance genes (ARGs) in faeces from cohabiting dogs and owners. Methods and Results DNA from faecal samples from 35 dogs and 35 owners was screened for the presence of 34 clinically relevant ARGs using high throughput qPCR. In total, 24 and 25 different ARGs were present in the dog and owner groups, respectively. The households had a mean of 9.9 ARGs present, with dogs and owners sharing on average 3.3 ARGs. ARGs were shared significantly more in households with dogs over 6 years old (3.5, interquartile range 2.75–5.0) than in households with younger dogs (2.5, interquartile range 2.0–3.0) (p = 0.02). Dogs possessed significantly more mecA and aminoglycoside resistance genes than owners. Conclusions Dogs and owners can act as reservoirs for a broad range of ARGs belonging to several antimicrobial resistance classes. A modest proportion of the same resistance genes were present in both dogs and owners simultaneously, indicating that ARG transmission between the dog and human gut is of minor concern in the absence of antimicrobial selection. Significance and Impact of the Study This study provides insight into the common dog and human gut resistomes, contributing to an improved knowledge base in risk assessments regarding ARG transmission between dogs and humans.Antimicrobial resistance—Do we share more than companionship with our dogs?publishedVersio

Transmission of Methicillin-Resistant Staphylococcus spp. from Infected Dogs to the Home Environment and Owners

Dogs with methicillin-resistant Staphylococcus spp. (MRS) infections often undergo treatment in their homes, interacting with their owners and surroundings. This close contact between dogs and owners may facilitate the interspecies transmission of MRS. Therefore, this study aimed to investigate the transmission of MRS from infected dogs to their owners and home environments. Seven households with dogs that had been diagnosed with methicillin-resistant S. pseudintermedius (MRSP) and one household with a dog with methicillin-resistant S. epidermidis (MRSE) participated in the study. Dogs, owners, and the home environments were screened for the presence of clinical MRS. A selection of 36 staphylococcal isolates were whole-genome sequenced and screened for resistance genes and virulence genes. Clinical MRS were primarily identified from the dogs and their immediate surroundings, but these were also detected in locations that were out of reach for the dogs, indicating indirect transmission. Two of eight owners carried clinical MRS in their nostrils, while one owner carried methicillin-susceptible S. pseudintermedius (MSSP). All clinical MRS were multi-resistant, and several possessed resistance genes that were not expressed phenotypically. Clinical MRSP persisted in the home environment for a prolonged period, despite infection recovery and one dog being euthanized. Regardless of the stable presence of MRSP in the surroundings, the owners in these homes remained negative, but tested positive for MSSP on three occasions

The Home Environment Is a Reservoir for Methicillin-Resistant Coagulase-Negative Staphylococci and Mammaliicocci

Coagulase-negative staphylococci (CoNS) and mammaliicocci are opportunistic human and animal pathogens, often resistant to multiple antimicrobials, including methicillin. Methicillin-resistant CoNS (MRCoNS) have traditionally been linked to hospitals and healthcare facilities, where they are significant contributors to nosocomial infections. However, screenings of non-hospital environments have linked MRCoNS and methicillin-resistant mammaliicocci (MRM) to other ecological niches. The aim of this study was to explore the home environment as a reservoir for MRCoNS and MRM. A total of 33 households, including households with a dog with a methicillin-resistant staphylococcal infection, households with healthy dogs or cats and households without pets, were screened for MRCoNS and MRM by sampling one human, one pet (if present) and the environment. Samples were analyzed by a selective culture-based method, and bacterial species were identified by MALDI-TOF MS and tested for antibiotic susceptibility by the agar disk diffusion method. Following whole-genome sequencing, a large diversity of SCCmec elements and sequence types was revealed, which did not indicate any clonal dissemination of specific strains. Virulome and mobilome analyses indicated a high degree of species specificity. Altogether, this study documents that the home environment is a reservoir for a variety of MRCoNS and MRM regardless of the type of household

Transmission of Methicillin-Resistant <i>Staphylococcus</i> spp. from Infected Dogs to the Home Environment and Owners

Dogs with methicillin-resistant Staphylococcus spp. (MRS) infections often undergo treatment in their homes, interacting with their owners and surroundings. This close contact between dogs and owners may facilitate the interspecies transmission of MRS. Therefore, this study aimed to investigate the transmission of MRS from infected dogs to their owners and home environments. Seven households with dogs that had been diagnosed with methicillin-resistant S. pseudintermedius (MRSP) and one household with a dog with methicillin-resistant S. epidermidis (MRSE) participated in the study. Dogs, owners, and the home environments were screened for the presence of clinical MRS. A selection of 36 staphylococcal isolates were whole-genome sequenced and screened for resistance genes and virulence genes. Clinical MRS were primarily identified from the dogs and their immediate surroundings, but these were also detected in locations that were out of reach for the dogs, indicating indirect transmission. Two of eight owners carried clinical MRS in their nostrils, while one owner carried methicillin-susceptible S. pseudintermedius (MSSP). All clinical MRS were multi-resistant, and several possessed resistance genes that were not expressed phenotypically. Clinical MRSP persisted in the home environment for a prolonged period, despite infection recovery and one dog being euthanized. Regardless of the stable presence of MRSP in the surroundings, the owners in these homes remained negative, but tested positive for MSSP on three occasions

Antimicrobial resistance—Do we share more than companionship with our dogs?

Aims To investigate and compare antimicrobial resistance genes (ARGs) in faeces from cohabiting dogs and owners. Methods and Results DNA from faecal samples from 35 dogs and 35 owners was screened for the presence of 34 clinically relevant ARGs using high throughput qPCR. In total, 24 and 25 different ARGs were present in the dog and owner groups, respectively. The households had a mean of 9.9 ARGs present, with dogs and owners sharing on average 3.3 ARGs. ARGs were shared significantly more in households with dogs over 6 years old (3.5, interquartile range 2.75–5.0) than in households with younger dogs (2.5, interquartile range 2.0–3.0) (p = 0.02). Dogs possessed significantly more mecA and aminoglycoside resistance genes than owners. Conclusions Dogs and owners can act as reservoirs for a broad range of ARGs belonging to several antimicrobial resistance classes. A modest proportion of the same resistance genes were present in both dogs and owners simultaneously, indicating that ARG transmission between the dog and human gut is of minor concern in the absence of antimicrobial selection. Significance and Impact of the Study This study provides insight into the common dog and human gut resistomes, contributing to an improved knowledge base in risk assessments regarding ARG transmission between dogs and humans