MRSA carriage in a pet therapy dog

A look at staphylococci from the one health perspective

Staphylococcus aureus and other staphylococcal species are resident and transient multihost colonizers as well as conditional pathogens. Especially S. aureus represents an excellent model bacterium for the "One Health" concept because of its dynamics at the human-animal interface and versatility with respect to host adaptation. The development of antimicrobial resistance plays another integral part. This overview will focus on studies at the human-animal interface with respect to livestock farming and to companion animals, as well as on staphylococci in wildlife. In this context transmissions of staphylococci and of antimicrobial resistance genes between animals and humans are of particular significance.

Canine-Assisted Interventions and the Relevance of Welfare Assessments for Human Health, and Transmission of Zoonosis: A Literature Review

CAIs (canine-assisted interventions) include "canine-assisted therapy" in which a therapist sets client-oriented goals, 'canine-assisted activities' with recreational goals for clients, and 'canine-assisted education/learning' in which teachers or coaches create learning goals for students or clients. CAIs vary in nearly every way; their only common trait is the involvement of dogs to respond to human need. However, the benefits of involving dogs are highly dependent on the animal's health and behavior. A dog exhibiting negative behavior or an unwell dog might pose a risk, especially for CAI target groups, specifically individuals with immunosuppression, chronic illness, children, elderly, etc. Therefore, positive animal welfare as preventative medicine to avoid incidents or transmission of zoonosis is an attractive hypothesis, with implications for human and animal, health and well-being. This review aims to summarize the current published knowledge regarding different aspects of welfare in CAIs and to discuss their relevance in the light of health and safety in CAI participants. As method for this study, a literature search was conducted (2001-2022) using the Prisma method, describing issues of dog welfare as defined in the Welfare Quality® approach. This welfare assessment tool includes 4 categories related to behavior, health, management, and environment; it was, therefore, applicable to CAIs. Results indicate that dogs working in CAIs are required to cope with diverse variables that can jeopardize their welfare. In conclusion, we propose regular welfare assessments for dogs in CAIs, which would also protect the quality of the CAI sessions and the clients' safety and well-being.

Colonization of Dogs and Their Owners with Staphylococcus aureus and Staphylococcus pseudintermedius in Households, Veterinary Practices, and Healthcare Facilities

There are uncertainties with respect to the transmission of methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA) and Staphylococcus pseudintermedius between dogs and humans. In this study, we investigated concomitant nasal colonization of dogs and humans in three cohorts. Cohort I, households owning dogs: In 42 of 84 households, 66 humans (36.9%) and 10 dogs (8.9%) carried S. aureus. MRSA, attributed to sequence type (ST) 22 and ST130, were detected in two (1.1%) of the humans but in none of the dogs. Typing by means of spa-typing and whole-genome sequencing (WGS) indicated eight transmissions of S. aureus between humans and dogs in 8 of 42 (19.0%) households with human S. aureus carriers, whereas in 11 of 38 (29.0%) households with ≥two persons and S. aureus colonization of humans, 15 human-to-human transmissions were observed (p = 0.43). S. pseudintermedius was isolated from 42 dogs (37.5%), but from only one human (0.6%). In this case, WGS-based typing indicated strong relatedness of this isolate with a canine isolate from the same household. Cohort II, dogs and their owners visiting a veterinary practice: Among 17 humans and 17 dogs attending a veterinary practice, MSSA was detected in three humans and two dogs, and S. pseudintermedius in only six dogs. Cohort III, dogs used for animal-assisted interventions in human healthcare facilities and their owners: MSSA was obtained in 1 of 59 dogs (1.7%) and in 17 of 60 (28.3%) of the dog owners, while S. pseudintermedius was isolated from seven (12%) dogs and one (1.7%) human owner. We conclude that the risk of exchanging S. aureus/MRSA between humans and dogs is higher than that for S. pseudintermedius.

Extended-Spectrum Beta-Lactamase-Producing and Carbapenem-Resistant Enterobacterales in Companion and Animal-Assisted Interventions Dogs

Animal-assisted interventions (AAIs) are being implemented in many countries for the beneficial effects they have on humans. Patients involved in AAI are often individuals at greater risk of acquiring infections, and these activities involve close contact between humans and animals, as is the case with humans living with a pet. The spread of multidrug-resistant Enterobacterales is a serious problem for human health; an integrated One Health strategy is imperative to combat this threat. Companion dogs can be a reservoir of multidrug-resistant pathogens, and animal-to-human transmission could occur during AAI sessions. The aim of this review was to collect the available data on the carriage of extended-spectrum beta-lactamase-producing and carbapenem-resistant Enterobacterales in companion dogs and in an AAI context. Several papers have generally addressed the issue of microbial transmission during AAIs. Studies on the intestinal carriage of extended-spectrum beta-lactamase and/or carbapenem-resistant Enterobacterales have mainly been conducted in companion animals while few data are available on the carriage in dogs participating in AAI sessions. This review aims to draw attention to the antibiotic resistance problem in a One Health context and to the importance of extending infection control measures to this human-animal interface, to keep the balance of benefits/risks for AAIs shifted towards the benefits of these activities.

One Health in hospitals: how understanding the dynamics of people, animals, and the hospital built-environment can be used to better inform interventions for antimicrobial-resistant gram-positive infections

Despite improvements in hospital infection prevention and control, healthcare associated infections (HAIs) remain a challenge with significant patient morbidity, mortality, and cost for the healthcare system. In this review, we use a One Health framework (human, animal, and environmental health) to explain the epidemiology, demonstrate key knowledge gaps in infection prevention policy, and explore improvements to control Gram-positive pathogens in the healthcare environment. We discuss patient and healthcare worker interactions with the hospital environment that can lead to transmission of the most common Gram-positive hospital pathogens – methicillin-resistant Staphylococcus aureus, Clostridioides (Clostridium) difficile, and vancomycin-resistant Enterococcus – and detail interventions that target these two One Health domains. We discuss the role of animals in the healthcare settings, knowledge gaps regarding their role in pathogen transmission, and the absence of infection risk mitigation strategies targeting animals. We advocate for novel infection prevention and control programs, founded on the pillars of One Health, to reduce Gram-positive hospital-associated pathogen transmission.

Risks associated with animal-assisted intervention programs: A literature review

The benefits of animal-assisted interventions (AAI), to utilize companion animals as an adjunctive treatment modality, is well-established and a burgeoning research field. However, few studies have evaluated the potential hazards of these programs, such as the potential for therapy animals to transfer hospital-associated pathogens between individuals and the hospital environment. Here we review the current literature on the possible risks of hospital-based AAI programs, including zoonotic pathogen transmission. We identified twenty-nine articles encompassing reviews of infection control guidelines and epidemiological studies on zoonotic pathogen prevalence in AAI. We observed substantial heterogeneity in infection control practices among hospital AAI programs. Few data confirmed pathogen transmission between therapy animals and patients. Given AAI's known benefits, we recommend that future research utilize a One Health framework to evaluate microbial dynamics among therapy animals, patients, and hospital environments. This framework may best promote safe practices to ensure the sustainability of these valuable AAI programs.

Current Standards and Practices Within the Therapy Dog Industry: Results of a Representative Survey of United States Therapy Dog Organizations

Organizations that deliver animal-assisted interventions (AAIs), as well as those that train, evaluate, and register therapy dogs, have proliferated in recent decades in the United States (U.S.). Each of these organizations has its own policies and procedures for screening, evaluating, and instructing dogs and their owners/handlers, but little is currently known about the range of different practices that exist nationwide. The aim of this project was to survey a representative, national sample of U.S. therapy dog organizations to investigate commonalities and differences in the types of practices in current use and to compare these to recommendations in existing published guidelines. The findings suggest the need for further research, and highlight a number of areas relating to dog welfare, human safety, and infection control in which many organizations were inconsistent in their adherence to existing guidelines. Of particular concern with regard to animal welfare was the finding that approximately half of the organizations surveyed imposed no time limit on the length of visits. Also, given the potential for zoonotic disease transmission, the finding that only a small minority of organizations prohibit the feeding of raw meat diets and treats to visiting dogs is concerning. This information will help to raise awareness among facilities with therapy animal programs and assist in the development of future best practices within the therapy dog industry.

The State of Animal-Assisted Interventions: Addressing the Contemporary Issues that will Shape the Future

As the worldwide popularity of animal-assisted interventions (AAIs) increases, the fieldis quickly approaching a paradigm shift, adjusting its image to incorporate more evidence-basedresearch and aligning its purpose for advancing a new future. Contemporary critical issues thatconfront the field today include, but are not limited, to research, animal welfare, practice guidelines,and public policy. This article will provide an overview of the history of AAI and the majormilestones that the field has undergone. The current state of AAI research will be scrutinized, andthe areas that warrant further study will be recommended. Special attention will be given to thecurrent state of animal welfare in AAI, the research that has been done in the area, and practiceguidelines that safeguard animal wellbeing. This article will then discuss how evidence-basedresearch and animal welfare guidelines inform the development of comprehensive professionalstandards and influence changes in public policy regarding AAI. The authors' perceptions for thefield's future trajectory will be presented, which will include solutions to move the field in thedirection that best advances the human-animal bond in research, practice, and public perception.

Evaluation of Risk of Zoonotic Pathogen Transmission in a University-Based Animal Assisted Intervention (AAI) Program

Introduction: Previous studies have shown that apparently healthy animals participating in Animal-Assisted Interventions (AAI) have the potential to asymptomatically carry and even transmit zoonotic pathogens to people, which is of particular concern for therapy animal teams visiting healthcare settings. This two-part study was designed to investigate the risk of zoonotic pathogen transmission within a university-based AAI program as a combination of the prevalence of these pathogens in the animal population as well as the handlers' understanding of the risks of zoonoses in AAI and their adherence to infection control practices.

Methods: In part one of the study, AAI program records were retrospectively reviewed and infectious disease screening test results were compiled from 22 dogs and 2 cats. Screening tests for dogs and cats included a zinc sulfate fecal float, fecal culture, and nasal and perianal skin swabs for methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant Staphylococcus pseudointermedius (MRSP). Additional tests for cats were blood cultures for Bartonella henselae and Toxoplasmosis IgG and IgM antibody titers. In part two, a survey was conducted of 40 registered therapy animal handlers to assess knowledge, attitudes, and perceptions regarding risk of infectious disease transmission in AAI settings, including risk to the animal, the handler, and those being visited.

Results: In part one, there were 17 total positive results of the 118 infectious disease screenings performed, 14 of which were potentially zoonotic organisms. In part two of the study, a majority (70%) of respondents expressed they had no concerns regarding infectious disease transmission in AAI settings. Despite handler education and guidelines, adherence to infection control practices was lacking.

Discussion: The results of this study support prior findings that animals participating in AAI can be asymptomatic carriers of zoonotic organisms. Compliance with infection control practices and hand hygiene are paramount to mitigate risk of zoonotic disease transmission, but was inconsistent among this group of handlers. Given the popularity of AAI programs in the U.S., similar studies should be performed on a larger scale to determine the level of adherence to currently recommended practices and potential need for improvement in infectious disease control education and/or policies.

Are all meticillin-resistant Staphylococcus aureus (MRSA) equal in all hosts? Epidemiological and genetic comparison between animal and human MRSA

Meticillin-resistant Staphylococcus aureus (MRSA) continues to pose a major threat to human health. In animals, MRSA has become established as a veterinary pathogen in pets and horses; in livestock, it presents a concern for public health as a reservoir that can infect humans and as a source of transferrable resistance genes. Genetic analyses have revealed that the epidemiology of MRSA is different in different animal hosts. While human hospital-associated MRSA lineages are most commonly involved in pet infection and carriage, horse-specific MRSA most often represent 'traditional' equine S. aureus lineages. A recent development in the epidemiology of animal MRSA is the emergence of pig-adapted strains, such as CC398 and CC9, which appear to have arisen independently in the pig population. Recent insight into the genome structure and the evolution of S. aureus has helped to explain key aspects of these three distinct epidemiological scenarios. This nonsystematic literature review summarizes the structure and variations of the S. aureus genome and gives an overview of the current distribution of MRSA lineages in various animal species. It also discusses present knowledge about the emergence and evolution of MRSA in animals, adaptation to different host species and response to selective pressure from animal-specific environments. An improved understanding of the genetics and selective pressure that underpin the adaptive behaviour of S. aureus may be used in the future to predict new developments in staphylococcal diseases and to investigate novel control strategies required at a time of increasing resistance to antimicrobial agents.

Household transmission of meticillin-resistant Staphylococcus aureus and other staphylococci

Although the role of pets in household transmission of meticillin-resistant Staphylococcus aureus (MRSA) has been examined previously, only minor attention has been given to the role of the abiotic household environment independent of, or in combination with, colonisation of pets and human beings to maintain transmission cycles of MRSA within the household. This report reviews published work about household transmission of S aureus and other staphylococci and describes contamination of household environmental surfaces and colonisation of pets and people. Household microbial communities might have a role in transfer of antimicrobial resistance genes and could be reservoirs for recolonisation of people, although additional research is needed regarding strategies for decontamination of household environments. Household-based interventions should be developed to control recurrent S aureus infections in the community, and coordination between medical and veterinary providers could be beneficial.

Role of MRSA reservoirs in the acute care setting

Background  Nosocomial infection remains the most common complication of hospitalisation. Despite infection control efforts, nosocomial methicillin-resistant Staphylococcus aureus (MRSA) transmission continues to rise. The associated costs of increased hospital stay and patient mortality cause considerable burden to the health system. Objectives  This review sought to evaluate the role of reservoirs, particularly the environment and equipment commonly found in the clinical area, in the transmission of MRSA within the acute hospital. This review updates a review previously completed by the authors and published by the Joanna Briggs Institute (2002). Search strategy  A systematic search for relevant published or unpublished literature was undertaken using electronic databases, the reference lists of retrieved papers and the Internet. This extended the search published in the original review. Databases searched included  Medline (1966-August Week 1 2005), CINAHL (1982-August Week 1 2005), EMBASE (1996-Week 33), as well as the Cochrane Library (Issue 3, 2005) and the Joanna Briggs Institute Evidence Library (August 2005). Selection criteria  All research reports published between 1990 and August 2005 in the English language that focused on the role of the environment and equipment commonly found in the clinical area on the nosocomial MRSA transmission in adult, paediatric or neonatal acute care settings were considered. Data collection and analysis  Two reviewers assessed each paper against the inclusion criteria and a validated quality scale. Studies that scored less than the mean quality score were excluded from the review. Data extraction was undertaken using a tool designed specifically for this review. Statistical comparisons of findings were not possible, so findings are presented in a narrative form. Results  Forty-two papers met the review inclusion criteria, of which 18 obtained a quality score above the threshold and are included in this review. Seven studies reported general investigations of MRSA in the clinical environment and 11 studies explored specific environmental aspects. All studies used exploratory, descriptive or comparative designs. The evidence suggests that MRSA strains within the environment often match those found in patients within that environment. MRSA can be found in the air around MRSA colonised or infected patients. The degree of airborne contamination is significantly increased by activities that promote airflow. Although the site of MRSA colonisation or infection can influence the degree of environmental contamination, these data are inconsistent. Therefore, there is limited evidence for tailoring infection control interventions based on the sites of MRSA colonisation or infection. The evidence suggests that the type of materials used in clinical equipment can influence the effectiveness of cleaning techniques. Current routine cleaning practices, including conventional terminal cleaning, do not necessarily effectively eradicate MRSA from the environment. This review demonstrates that there is a link between the environment and hospital equipment and the transmission of MRSA within the acute hospital setting. Further well-designed research is urgently required to explore the efficacy of specific cleaning and decontamination methods, staff compliance with infection control practices and the range of factors that affect the incidence of MRSA contamination of the environment and equipment commonly found in the clinical area.

Evaluation of pet contact as a risk factor for carriage of multidrug-resistant staphylococci in nursing home residents

BACKGROUND

Pets, often used as companionship and for psychological support in the therapy of nursing home residents, have been implicated as reservoirs for antibiotic-resistant bacteria. We investigated the importance of pets as reservoirs of multidrug-resistant (MDR) staphylococci in nursing homes.

METHODS

We assessed the carriage of MDR staphylococci in pets and in 2 groups of residents, those living in nursing homes with pets and those living without pet contacts. We collected demographic, health status, and human-pet contact data by means of questionnaires. We assessed potential bacteria transmission pathways by investigating physical resident-to-pet contact.

RESULTS

The observed prevalence of MDR staphylococci carriage was 84/229 (37%) in residents living with pets and 99/216 (46%) in those not living with pets (adjusted odds ratio [aOR], 0.6; 95% confidence interval [CI], 0.4-0.9). Active pet contact was associated with lower carriage of MDR staphylococci (aOR, 0.5; 95% CI, 0.4-0.8). Antibiotic treatment during the previous 3 months was associated with significantly increased risk for MDR carriage in residents (aOR, 3.1; 95% CI, 1.8-5.7).

CONCLUSIONS

We found no evidence that the previously reported benefits of pet contact are compromised by the increased risk of carriage of MDR staphylococci in residents associated with interaction with these animals in nursing homes. Thus, contact with pets, always under good hygiene standards, should be encouraged in these settings.

Community-associated methicillin-resistant Staphylococcus aureus: epidemiology and clinical consequences of an emerging epidemic

Staphylococcus aureus is an important cause of skin and soft-tissue infections (SSTIs), endovascular infections, pneumonia, septic arthritis, endocarditis, osteomyelitis, foreign-body infections, and sepsis. Methicillin-resistant S. aureus (MRSA) isolates were once confined largely to hospitals, other health care environments, and patients frequenting these facilities. Since the mid-1990s, however, there has been an explosion in the number of MRSA infections reported in populations lacking risk factors for exposure to the health care system. This increase in the incidence of MRSA infection has been associated with the recognition of new MRSA clones known as community-associated MRSA (CA-MRSA). CA-MRSA strains differ from the older, health care-associated MRSA strains; they infect a different group of patients, they cause different clinical syndromes, they differ in antimicrobial susceptibility patterns, they spread rapidly among healthy people in the community, and they frequently cause infections in health care environments as well. This review details what is known about the epidemiology of CA-MRSA strains and the clinical spectrum of infectious syndromes associated with them that ranges from a commensal state to severe, overwhelming infection. It also addresses the therapy of these infections and strategies for their prevention.

Methicillin-resistant staphylococci isolated from healthy horses and horse personnel in Italy

Methicillin-resistant staphylococci (MRS) were isolated from nasal swabs of 56 of 159 (35.2%; 95% confidence interval [CI]: 27.9-43.2%) healthy horses. Two nasal swabs were collected from each horse; 43 of 159 (27%; 95% CI: 20.5-34.8%) of the cohort were colonized by MRS strains in 1 nostril, while in the remaining 13 of 159 (8.2%; 95% CI: 4.6-13.9%), different or identical MRS strains were isolated in both nostrils. Of the 29 humans in close contact with the horses tested, 4 (13.8%; 95% CI: 4.5-32.6%) were found to be carriers of MRS. All isolates were coagulase negative with the exception of 2 coagulase-positive MRS strains, Staphylococcus aureus and Staphylococcus pseudintermedius, both isolated from horses. To assay the methicillin resistance, a susceptibility test to oxacillin with standardized disk diffusion method, a PBP-2a latex agglutination test, and a methicillin resistance gene (mecA) polymerase chain reaction assay were performed. Pulsed-field gel electrophoresis patterns of isolates from horses and humans in close contact with the horses revealed similarity. The results suggest evidence of transmission between animals, from animals to humans, and vice versa.

Reflection paper on MRSA in food-producing and companion animals: epidemiology and control options for human and animal health

The scope of this reflection paper was to review the latest research on the risk of MRSA infection and colonization in animals. Attention focused on occurrence, risk factors for colonization and infection, and human contact hazard for livestock, horses, and companion animals. Whereas the clonal relationship between MRSA strains of CC398 is straightforward in livestock this is less obvious in horses. Small companion animals typically share MRSA strains that seem to exchange with a human reservoir. Management and therapeutic options have been suggested for livestock, horses, companion animals, as well as instructions on safety measures for persons in contact with animals. Conclusions were drawn with emphasis on future research activities, especially to confirm the apparent evolution of the organism and to demonstrate efficiency of control strategies.

Companion animals: a reservoir for methicillin-resistant Staphylococcus aureus in the community?

This article reviews the literature on the epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) in dogs, cats and horses. Over the past 10 years, MRSA has emerged as an important pathogen in veterinary medicine, especially in countries with a high MRSA burden in human hospitals. During the same period, community-associated MRSA (CA-MRSA) infections in humans without apparent links to healthcare facilities have increased dramatically. Although animal infections occur outside human hospitals, significant epidemiological, clinical and genetic differences exist between CA-MRSA in humans and the majority of MRSA infections in the different animal species. The recognition of MRSA in animals has raised concern over their role as potential reservoirs or vectors for human MRSA infection in the community. However, available data on MRSA transmission between humans and companion animals are limited and the public health impact of such transmission needs to be the subject of more detailed epidemiological studies.

Methicillin-resistant Staphylococcus aureus in resident animals of a long-term care facility

Animals provide benefits to elderly and chronically ill people by decreasing loneliness, increasing social interactions, and improving mental health. As a result, many hospitals and long-term care facilities allow family pets to visit ill or convalescing patients or support animal-assisted therapy programs. These include programs that have resident animals in long-term care facilities. Despite the benefits, there are concerns about disease transmission between pets and patients. Antibiotic-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), are a recognized problem in healthcare settings leading to refractory infections and potentially life-threatening illnesses. MRSA has been isolated from numerous animal species, yet few studies are available on the carriage of this pathogen in animals residing in long-term care facilities. Our objective was to characterize MRSA carriage among resident animals in a long-term care facility.

METHODS

To document MRSA colonization, nasal swabs from 12 resident animals (one dogs and 11 cats) of a long-term care facility were collected weekly for 8 weeks. Staphylococcus isolates were characterized by antimicrobial susceptibility and MRSA isolates were further characterized by pulsed-field gel electrophoresis (PFGE). PFGE isolate patterns were compared with an existing database of MRSA isolate patterns at the Minnesota Department of Health.

RESULTS

Two of 11 cats were colonized with MRSA. MRSA was recovered from five of eight weekly samples in one cat and two of eight weekly samples in the other cat. All isolates were classified as USA100 (healthcare-associated strains).

DISCUSSION

Long-term care resident animals may acquire MRSA. Clonally related strains were identified over the 8-week sampling period. It is unclear if pets serve as an on-going source of infection to their human companions in long-term care facilities.

Prevalence of Staphylococcus aureus carriage among dogs and their owners

Case reports have indicated transmission of Staphylococcus aureus between humans and pets. We investigated associations between level of contact between dog and owner, and S. aureus colonization. In a cross-sectional study, nasal carriage and antibiotic susceptibility of S. aureus was determined for 830 dogs and 736 owners. Relatedness of isolates was investigated using antibiograms and pulsed-field gel electrophoresis (PFGE). Associations between carriage and demographics or amount of contact between owners and dogs were documented. S. aureus was isolated in 24% of humans and 8.8% of dogs. Antibiotic resistance was significantly more common in canine isolates. Of 17 owner/dog colonized pairs, six were indistinguishable by PFGE. Colonization of dogs was not associated with close human contact, but was strongly associated with health-care occupations (OR 3.29, 95% CI 1.49-7.26, P=0.002). In outbreak situations health-care workers' pets should be considered as a source of S. aureus. High rates of resistance indicate increased monitoring of antibiotic use in veterinary practice is needed.

Empowering your patients in the fight against methicillin-resistant Staphylococcus aureus

PURPOSE

To provide patient teaching points for primary care management and control of methicillin-resistant Staphylococcus aureus (MRSA) through application of the latest research regarding transmission of this bacteria.

DATA SOURCES

Case reports, scientific literature, and the recommendations of expert professional groups.

CONCLUSIONS

MRSA is a well studied yet continually evolving superbug. There is a paucity of literature regarding detailed home management and containment of MRSA. This review acknowledges the critical importance of patient education regarding MRSA infections and empowers patients with knowledge that can positively impact treatment outcomes.

IMPLICATIONS FOR PRACTICE

Awareness of transmission modes and recognition of sources for relapse of infectious states can curb the spread of MRSA in the community.

Guidelines for animal-assisted interventions in health care facilities

Many hospitals and long-term care facilities in North America currently permit animals to visit with their patients; however, the development of relevant infection control and prevention policies has lagged, due in large part to the lack of scientific evidence regarding risks of patient infection associated with animal interaction. This report provides standard guidelines for animal-assisted interventions in health care facilities, taking into account the available evidence.

Role of MRSA reservoirs in the acute care setting

BACKGROUND

Nosocomial infection remains the most common complication of hospitalisation. Despite infection control efforts, nosocomial methicillin-resistant Staphylococcus aureus (MRSA) transmission continues to rise. The associated costs of increased hospital stay and patient mortality cause considerable burden to the health system.

OBJECTIVES

This review sought to evaluate the role of reservoirs, particularly the environment and equipment commonly found in the clinical area, in the transmission of MRSA within the acute hospital. This review updates a review previously completed by the authors and published by the Joanna Briggs Institute (2002).

SEARCH STRATEGY

A systematic search for relevant published or unpublished literature was undertaken using electronic databases, the reference lists of retrieved papers and the Internet. This extended the search published in the original review.Databases searched included Medline (1966-August Week 1 2005), CINAHL (1982-August Week 1 2005), EMBASE (1996-Week 33), as well as the Cochrane Library (Issue 3, 2005) and the Joanna Briggs Institute Evidence Library (August 2005).

SELECTION CRITERIA

All research reports published between 1990 and August 2005 in the English language that focused on the role of the environment and equipment commonly found in the clinical area on the nosocomial MRSA transmission in adult, paediatric or neonatal acute care settings were considered.

DATA COLLECTION AND ANALYSIS

Two reviewers assessed each paper against the inclusion criteria and a validated quality scale. Studies that scored less than the mean quality score were excluded from the review. Data extraction was undertaken using a tool designed specifically for this review. Statistical comparisons of findings were not possible, so findings are presented in a narrative form.

RESULTS

Forty-two papers met the review inclusion criteria, of which 18 obtained a quality score above the threshold and are included in this review. Seven studies reported general investigations of MRSA in the clinical environment and 11 studies explored specific environmental aspects. All studies used exploratory, descriptive or comparative designs. The evidence suggests that MRSA strains within the environment often match those found in patients within that environment. MRSA can be found in the air around MRSA colonised or infected patients. The degree of airborne contamination is significantly increased by activities that promote airflow. Although the site of MRSA colonisation or infection can influence the degree of environmental contamination, these data are inconsistent. Therefore, there is limited evidence for tailoring infection control interventions based on the sites of MRSA colonisation or infection. The evidence suggests that the type of materials used in clinical equipment can influence the effectiveness of cleaning techniques. Current routine cleaning practices, including conventional terminal cleaning, do not necessarily effectively eradicate MRSA from the environment. This review demonstrates that there is a link between the environment and hospital equipment and the transmission of MRSA within the acute hospital setting. Further well-designed research is urgently required to explore the efficacy of specific cleaning and decontamination methods, staff compliance with infection control practices and the range of factors that affect the incidence of MRSA contamination of the environment and equipment commonly found in the clinical area.

Characterisation of methicillin-resistant Staphylococcus aureus isolates from dogs and their owners

Ten methicillin-resistant Staphylococcus aureus (MRSA) isolates from healthy owners and their pets were characterised by susceptibility testing, staphylococcal chromosome cassette (SCC)mec and agr typing, and detection of the Panton-Valentine leukocidin (PVL) genes. Two human and three dog isolates harbouring SCCmec type III appeared to be of hospital origin. The five remaining isolates carried SCCmec type IV, with three being multidrug-resistant. One type IV isolate was PVL-positive and a prototypic agr type 3, typified by strain MW2. This is the first report of this type in association with nasal carriage. Drug resistance may be increasing among community isolates of MRSA.

Prevalence of oxacillin- and multidrug-resistant staphylococci in clinical samples from dogs: 1,772 samples (2001–2005)

OBJECTIVE

To determine whether resistance to oxacillin and other antimicrobials in 3 Staphylococcus spp commonly isolated from dogs increased from 2001 to 2005.

DESIGN

Retrospective case series.

SAMPLE POPULATION

1,772 clinical samples of various types obtained from dogs examined at the University of Tennessee Veterinary Teaching Hospital or at regional veterinary hospitals and submitted to the bacteriology and mycology laboratories associated with the teaching hospital.

PROCEDURES

Samples were submitted by attending veterinarians to the bacteriology and mycology laboratories for routine aerobic microbial culture. Identification and antimicrobial susceptibility procedures were performed on all isolates. Susceptibility reports for each antimicrobial and Staphylococcus spp were determined from aggregate electronically archived test results. Oxacillin and multidrug resistance for Staphylococcus intermedius was analyzed by reviewing disk diffusion zone measurements.

RESULTS

Oxacillin resistance increased among S. intermedius isolates during the past 5 years, and the increase was associated with multidrug resistance. In 2005, 1 in 5 Staphylococcus spp isolates from canine clinical samples was resistant to oxacillin. The most common staphylococcal species isolated were S. intermedius (n = 37), Staphylococcus schleiferi (21), and Staphylococcus aureus (4), and frequencies of oxacillin resistance in isolates of these species were 15.6%, 46.6%, and 23.5%, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE

Veterinarians should be aware of the potential for empiric drug treatment failures in instances where Staphylococcus spp infections are common (eg, pyoderma). Judicious use of bacterial culture and susceptibility testing is recommended.

Antimicrobial Resistance

Development of antimicrobial resistance is an inevitable consequence of exposure of microorganisms to antimicrobial agents. Although emergence of resistance cannot be prevented, it can be retarded by minimizing use of antimicrobial agents and avoiding selection of relatively resistant pathogenic and nonpathogenic strains caused by exposure to tissue concentrations that confer a competitive advantage. Most attention in veterinary medicine has focused on the emergence of resistance in food-borne pathogens, with relatively little attention being devoted to small companion animals, despite the frequent use of antimicrobial agents in these animals, evidence that resistance is emerging, and potential for transfer of resistance between companion animals and people. To retard further emergence of resistance in small companion animals, it is imperative that surveillance programs be instituted to monitor development of resistance.

Prevalence of zoonotic agents in dogs visiting hospitalized people in Ontario: implications for infection control

Visitation of hospitalized people by dogs is becoming commonplace, but little is known about the potential health risks of introducing dogs to healthcare settings. This cross-sectional study evaluated the prevalence of zoonotic agents in a group of 102 visitation dogs from a variety of sources across Ontario. Between May and July 2004, owners were interviewed by a standardized questionnaire while dogs underwent a standardized physical examination. One specimen of faeces, hair-coat brushings and one rectal, aural, nasal, oral and pharyngeal swab were collected from each dog and tested for 18 specific pathogens. All dogs were judged to be in good health. Zoonotic agents were isolated from 80 out of 102 (80%) dogs. The primary pathogen was Clostridium difficile, which was isolated from 58 (58%) faecal specimens. Seventy-one percent (41/58) of these isolates were toxigenic. Extended-spectrum beta-lactamase Escherichia coli was isolated from one (1%) dog, extended-spectrum cephalosporinase E. coli was isolated from three (3%) dogs, and organisms of the genus Salmonella were isolated from three (3%) dogs. Pasteurella multocida or Pasteurella canis was isolated from 29 (29%) oral swabs, and Malassezia pachydermatis was isolated from eight (8%) aural swabs. Giardia antigen was present in the faeces of seven (7%) dogs, while Toxocara canis and Ancylostoma caninum were detected in two (2%) dogs and one (1%) dog, respectively. Methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci, Campylobacter spp., Microsporum canis, group A streptococci, Pseudomonas aeruginosa and Cryptosporidium spp. were not detected. Further information is needed before the full implications of these findings for infection control can be assessed properly.