MRSA Infections:
The roles of people, pets and the home
Delaware Healthy Homes Summit
Children’s Health & the Indoor Environment
March 12, 2014
Meghan F. Davis, DVM MPH PhD
Johns Hopkins Bloomberg School of Public Health
[email protected]
1
About this Lecture and Lecturer
• Dr. Meghan Davis
• Veterinarian
– Dairy/Mixed animal practice (PA)
– Companion animal practice (PA & MD)
– Rabies clinics (MD)
• Hopkins Postdoc in Environmental
Health
– Zoonotic disease research
– Focus on household bacterial exposures
– One health approach
• This lecture: Zoonoses in the Household
2
Outline
• The home environment & infectious disease
– Zoonoses & pets
– Children in the home
• The importance of staphylococcal bacteria
• Pets and Environmental Transmission of Staphylococci study
• Broader implications of pets in the home
3
What is a zoonosis?
•
•
•
•
Zoo- animal + -nosis disease
Disease transmitted to humans from animals (usually vertebrates)
May have animal reservoir
May be novel “emergence”
What is a zoonosis?
•
•
•
•
Zoo- animal + -nosis disease
Disease transmitted to humans from animals (usually vertebrates)
May have animal reservoir
May be novel “emergence”
Many diseases we call zoonoses
actually impact both people
and animals and can be
transmitted in both directions
(from animals to people
and from people to animals)
One Health: the Venn diagram
6
Household pets
• Pet species
–
–
–
–
–
Dogs, cats
“Pocket pets” – rodents, rabbits, etc.
Reptiles – turtles, lizards, snakes, etc.
Birds – parrots, etc.
Horses
• High level of contact with humans
& their environments
The household: a community nexus
8
The household: a community nexus
9
Davis et al., The role of the household in transmission of methicillin-resistant S. aureus and other staphylococci.
The Lancet Infectious Diseases 2012, in press.
Household Contamination Sites
10
Davis et al., The role of the household in transmission of methicillin-resistant S. aureus and other staphylococci.
The Lancet Infectious Diseases 2012, in press.
The Importance of Transmission Dynamics
Conventional clinical approaches focus on
short-term clearance following treatment in
the index patient only
Davis et al., The role of the household in transmission of methicillin-resistant S. aureus and other staphylococci.
The Lancet Infectious Diseases 2012
Transmission dynamics: consider the household as a unit
Davis et al., The role of the household in transmission of methicillin-resistant S. aureus and other staphylococci.
The Lancet Infectious Diseases 2012
Why staphylococci matter
• Share the genes for antimicrobial
resistance + the staphylococcal
chromosomal cassette (SCCmec, methicillin resistance)
• Induce toxic effects (e.g. toxic shock syndrome, enterotoxin)
• Survive on environmental surfaces
13
Background
Staphylococci: the usual suspects
• S. aureus, incl. methicillin-resistant strains (MRSA)
– Primary pathogens of people, can colonize pets & cause pet infections
– Livestock and horses have animal-adapted strains (e.g. ST398, USA500)
• S. pseudintermedius, incl. methicillin-resistant strains (MRSP)
– Primary pathogen of pets, esp. dogs, can colonize people & cause rare
human infections
• S. schleiferi, subsp. coagulans & subsp. schleiferi
– Emerging pathogen of pets, esp. dogs, can colonize people & cause rare
human infections
These are coagulase-positive staphylococci (CPS)*
* except S. schleiferi subsp. schleiferi
14
Background
MRSA Epidemiology
• Increases in MRSA nasal colonization rates based on U.S. population
estimates between 2001 and 2004
– By 2003-04 (NHANES), almost 20% of cases were associated with strain
types associated with community disease
• Increases since 1990s and 2000s appear to be due to rise in
community-associated (CA-)MRSA
Image source: Microbiology Online
15
+
=
PETS AND ENVIRONMENTAL TRANSMISSION
OF STAPHYLOCOCCI STUDY (P.E.T.S.)
Goals:
(1) To identify the roles of animals and
the environment as reservoirs of
MRSA in households, related to
human colonization and infection
(2) To evaluate animal health impacts
from exposure to people with MRSA
16
Nested Study Design
• “Epidemiology and Prevention of MRSA
in the Community” aka CURE
– Registered randomized controlled trial
(NCT00966446)
– Enrollment: 223 index patients (people)
with recent MRSA infection and their
household members
– Randomization to treatment protocol for
people (two decolonization treatment
options, education control)
• PETS study nested in CURE trial
3 months
– 95 households (43% of CURE)
– 184 pets in 67 households
17
Methods
Figure: Amy Brazil
PETS Household Enrollment
We are here
18
Results
PETS Overview
Inclusion criteria: MRSA-exposed populations
Pets of all species
(aim of PETS study)
Household and pet-related environments
(aim of PETS study)
19
Methods
People living in the house
(aim of CURE study)
PETS Overview: workflow
Collected samples from home
surfaces, pets & beds
Conducted surveys of
household & pet
characteristics
Performed laboratory
testing of samples:
• Culture-dependent
with molecular ID (PCR)
nuc
mecA/C
• Culture-independent
(microbiome,
Illumina MiSeq)
F primer with barcode
R primer
16S V4~254 bp
20
Methods
Household Enrollment: most households were urban
PETS study, n (%)
Baseline
Follow-up
96*
65
Enrollment center
HUP
CHOP
Philly community hospitals (2)
Hershey Medical Center
18 (19%)
35 (36%)
21 (22%)
22 (23%)
10 (15%)
24 (37%)
13 (20%)
18 (28%)
Randomization
Education
Unsupervised decolonization
Supervised decolonization
33 (35%)
29 (31%)
33 (35%)
26 (40%)
18 (28%)
21 (32%)
Home location
Urban
Suburban
Rural (ag and non-ag)
64 (67%)
19 (20%)
13 (13%)
37 (57%)
17 (26%)
11 (17%)
Households enrolled
* one house did not complete CURE baseline enrollment
21
Household Enrollment: many households had children
• Enrollment: 398 at baseline, 263 at follow-up
• On average 4.3 people per household (range 1-11)
• Child index patient: 44% baseline, 46% at follow-up
– CHOP and HMC enrollment centers
22
Pet Enrollment: most households had pets
PETS study
Baseline
Follow-up
95
65
67 (71%)
44 (68%)
Pets enrolled, N
184
1303
Dogs, N (%)
71 (39%)
38 (29%)
Cats, N (%)
68 (37%)
50 (38%)
Pocket pets, N (%)1
11 (6%)
9 (7%)
Reptiles, N (%)2
21 (11%)
18 (14%)
Freshwater fish tanks, N (%)
11 (6%)
13 (10%)
Birds (parrots), N (%)
2 (1%)
2 (2%)
Households enrolled, N
Homes with pets, N (%)
1 Chinchillas,
hamsters, rat, sugar glider,
ferret, rabbit
2 Turtles (primarily aquatic), lizards,
snake
23
Results
3 113
continuing pets, 17 new
pets at follow-up (10 cats, 3
reptiles, 3 fish, and a hamster)
Over half of pets lick people or share beds with them
Baseline
24
Pets enrolled, N
184
Female, N (%)
103 (56%)
Spayed/Neutered, N (%)
55 (30%)
Median age (in months)
44
Ever go outside, N (%)2
37 (20%)
Veterinary contact in past year, N (%)
55 (30%)
Abx use in past year, N (%)
10 (5%)
Ever lick people, N (%)
79 (43%)
Ever share a bed with people, N (%)
76 (41%)
63% of pets lick,
share beds, or both
CULTURE-DEPENDENT RESULTS
25
Household environments are contaminated with MRSA
PETS study
MRSA
MSSA
MSSP
60 (63%)
20 (21%)
4 (4%)
Common room, n=96*
53 (55%)
16 (17%)
3 (3%)
Bedroom (index pt), n=92
53 (58%)
13 (14%)
2 (2%)
Baseline visit, n=96*
Based on screening one isolate per visit for each location group (common room,
bedroom)
*95 homes concurrently enrolled in CURE and eligible for longitudinal study
All homes with S. pseudintermedius had pets
Environmental MRSA contamination was associated significantly with the
proportion of people who were MRSA-positive at the time of sampling.
This association was non-significant with MRSA-positive pets.
26
Results
Household environments are contaminated with MRSA
PETS study
MRSA
MSSA
MSSP
60 (63%)
20 (21%)
4 (4%)
Common room, n=96
53 (55%)
16 (17%)
3 (3%)
Bedroom (index pt), n=92
53 (58%)
13 (14%)
2 (2%)
33 (50%)
13 (20%)
3 (5%)
Common room, n=65
27 (42%)
9 (14%)
2 (3%)
Bedroom (index pt), n=57
28 (49%)
9 (33%)
2 (3%)
Baseline visit, n=96
Follow-up visit, n=65
21/65 (33%) homes were MRSA-positive at both visits.
Randomization to a treatment group lowered odds for common room
contamination with MRSA at both visits, but this estimate of association was
non-significant.
27
Results
Pet Sampling
Nares
Mouth
Dorsum
Perineum
Most sensitive!
Inguinal Region
Figure: Sally Ann Iverson
Methods
Dogs carry S. pseudintermedius more often than S. aureus
PETS study - baseline prevalence, n (%)
MRSA
MSSA
MSSP1
13 (7%)
14 (8%)
31 (18%)
Dogs, n=71
5 (7%)
9 (13%)
27 (38%)1
Cats, n=63*
7 (11%)
4 (6%)
2 (3%)
Pocket pets, rabbit, ferret, n=11
0 (0%)
0 (0%)
0 (0%)
Reptiles, n=21
0 (0%)
1 (5%)
1 (5%)
Freshwater fish tanks, n=11
1 (9%)
0 (0%)
1 (9%)
Birds (parrots), n=2
0 (0%)
0 (0%)
0 (0%)
Pets overall, n=179*
Based on screening one isolate per pet per visit
Single S. schleiferi isolate identified (dog)
1Additional single MRSP isolate identified
* Five cats enrolled but not sampled, results based on prevalence among sampled pets
29
Results
Can’t completely ignore exotic species
PETS study prevalence, n (%)
MRSA
MSSA
MSSP1
13 (7%)
14 (8%)
31 (18%)
Dogs, n=71
5 (7%)
9 (13%)
27 (38%)1
Cats, n=63*
7 (11%)
4 (6%)
2 (3%)
Pocket pets, rabbit, ferret, n=11
0 (0%)
0 (0%)
0 (0%)
Reptiles, n=21
0 (0%)
1 (5%)
1 (5%)
Freshwater fish tanks, n=11
1 (9%)
0 (0%)
1 (9%)
Birds (parrots), n=2
0 (0%)
0 (0%)
0 (0%)
Pets overall, n=179*
First report of MRSA-positive fish tank
30
Contaminated homes are associated with pet MRSA
MRSA
• Pets with owner-reported history of pet antimicrobial use in the
past year was associated with 7-fold increase in odds for MRSA
positivity (p<0.01).
• Contact with veterinary hospitals in the past year was not statistically
significantly associated with MRSA positivity.
• Positive home environments were associated with a 9-fold
increase in odds for MRSA positivity (p=0.04)
• Proportion of positive humans in the household with a nonsignificant 9-fold increase in odds for MRSA positivity (p=0.17).
Logistic regression modeling, controlled for clustering at the household level
Bivariate ORs reported; these remained generally consistent in multivariate models
31
Pets may be persistently positive for staphylococci
PETS study, three-month prevalence, n (%)
MRSA
MSSA
MSSP1
7 (5%)
12 (9%)
19 (15%)
Dogs, n=38
4 (11%)
5 (13%)
18 (45%)
Cats, n=48*
3 (6%)
7 (15%)
1 (2%)
Pocket pets, rabbit, ferret, n=9
0 (0%)
0 (0%)
0 (0%)
Reptiles, n=18
0 (0%)
0 (0%)
0 (0%)
Freshwater fish tanks, n=13
0 (0%)
0 (0%)
0 (0%)
Birds (parrots), n=2
0 (0%)
0 (0%)
0 (0%)
Pets overall, n=128*
Persistently positive pets (from 111 pets sampled longitudinally):
MRSA, 3%: 2 cats, 1 dog
MSSA, 3%: 2 cats, 1 dog
MSSP, 10%: 10 dogs, 1 cat
MRSP, 1%: 1 dog
32
Results
Clinical significance: cases of MRSA in person and pet
• Case in owner: Male Caucasian, 31 years old
– Neck abscess in June 2012
– Drained, treated successfully with IV clindamycin and oral trimethoprimsulfadimethoxazole
• Case in dog: FS Italian Mastiff, 23 months old
–
–
–
–
Cruciate surgery on the day after baseline visit (July 2012)
Only dog to have surgery between baseline and follow-up visits
Developed MRSA post-surgical infection two weeks after procedure
Treated successfully with clindamycin
• Pet’s bed the only site positive
for MRSA at baseline visit
33
Cases developed within one month of each other
34
Molecular typing links MRSA strains
PFGE, DICE coefficient ≥85%
35
Antimicrobial susceptibility changes over time
Person
treated
with
SXT
Dog
treated
with
CLI
36
MRSA
isolates
Conclusions from PETS study
• Positive home environments were associated with risk for both
positive people and positive pets.
• Pets may be more likely to carry veterinary staphylococcal bacteria
than a human pathogenic bacterium like MRSA, and this varies by
species of pet.
• Dogs were more likely to carry Staphylococcus pseudintermedius
• Cats were more likely to carry Staphylococcus aureus
• Case report illustrates clinical significance and transmission
dynamics within a household involving both people and a dog.
• Case report also suggests response to selective pressure from
antimicrobial use in either a person or a pet.
37
Selected other zoonoses/anthroponoses
• Bacteria
• Salmonella associated with reptiles - does cause disease in reptiles!
• Campylobacter, E. coli, etc.
• Parasites
• Hookworms and roundworms – puppies and kittens
• Cryptosporidium parvum – HIV+ and immunosuppressed at risk
• Toxoplasma gondii – cat feces and gardening a source for pregnant women
• Viruses
• Influenza A – variable risk, hard to quantify
• Rabies virus - household pets required to be vaccinated
38
Source: Centers for Disease Control and Prevention, November 2010
Pathogen characteristics that influence infectious disease
transmission
• Physical structure
– Size, shape, etc.
• Survival/growth in environment or reservoir
– Inoculating dose
• Lifecycle characteristics (complexity)
– Important for vector-borne diseases (host, vector, infectious agent)
• Antigen
– Structures (epitopes) on pathogen that induce immune response
• Physiologic barrier (host)
Vectors
• GENERAL: Indirect pathway of transmission, e.g. fomite
• SPECIFIC: arthropod or other insect host which either serves as a
mechanical or biological route of disease transmission
– Mechanical: Flies carry bacteria on legs
– Biological: Mosquitoes are part of the malaria parasite lifecycle
Pests
– Sources of discomfort
• lice, fleas, mites, bedbugs, spiders
– Vectors of disease
Mosquitoes
Malaria, yellow fever, dengue fever, filariasis, encephalitis,
West Nile Virus
Flies
Typhoid fever, cholera, dysentery, parasitic worm infections
Cockroaches
Allergic reactions, asthma attacks, skin irritations
Body lice
Typhus fever, trench fever
Rat fleas
Plague
Ticks
Rocky Mountain spotted fever, Lyme disease, anaplasmosis,
erlichiosis
Household pets and vectors
• Mechanical vector for pests
– Ticks (Lyme disease, other tick-borne diseases)
• Amplifying host
– Fleas
• Treatment may lead to increase in household pesticide use
Product
Active Ingredient
Product type
Revolution
Selamectin
Prescription drug
K9 Advantix II
Imidacloprid & Permethrin
Insecticide
Vectra 3D
Dinotefuran & Permethrin
Insecticide
Please note that permethrins are toxic to cats; ivermectins are toxic to collie-type dogs
43
Potential human health hazards from pesticides
• Carcinogens or potentially carcinogenic
– 60% of all herbicides
– 90% of all fungicides
– 30% of insecticides
• Endocrine disruptors
– Feminization of males
– Birth defects
– Impaired fertility
• Immune system disruptors – infectious disease incidence increases,
contact dermatitis seen
Animal-associated bioaerosols
• Allergens / dander
• Culturable microbes
•
Specific pathogens, e.g. MRSA
• Microbial products
• Endotoxin (LPS)
• Superantigens
• Bacterial cell wall components (peptidoglycan, lipoteichoic acid)
45
But it’s not all bad!
• Pets may contribute to household microbial diversity / microbial
sharing among household members
– PETS study findings corroborate the literature
• A diversity of microbial exposures in early childhood may protect
against development of asthma and other allergic disorders
Health benefits of pet ownership
• Mental health / Mood improvements
• Increased fitness
– Walking the dog leads to more routine owner exercise
Image source: Wikimedia
Take home messages
• Researchers: be aware of the influence of household pets
– Particularly on infectious disease
– Also on other correlated household environmental exposures, such as
pesticides and endotoxin
• Clinicians: consider pets and the home environment with cases of
recurrent infection with potentially zoonotic disease agents
• Public health practitioners: ask about pet ownership when
investigating outbreaks
• Community nurses: evaluate the whole household
• Engineers: design homes with pets and infectious diseases in mind
• All: consider that pets may be a sentinel for home-based exposures
(toxicant or infectious agent)
– Birds and amphibians are particularly sensitive to toxicants
Thank you!
CURE: Ebbing Lautenbach, Irving Nachamkin, Pam Tolomeo,
and the field and laboratory team, especially John, Grace and Robin
PETS: Sally Ann Iverson, Amy Brazil, Aimee Vasse, Rachael Joseph,
Patrick Baron, Elana Youssef, Jackie Ferguson
JHSPH: John Groopman, Peter Lees, Ken Nelson, & Ellen Silbergeld;
with thanks to David Sack & his lab group and the EHS department
Penn: Daniel Morris, Shelley Rankin, Elizabeth Grice, Ana Misic
PETS Funding: Johns Hopkins Center for a Livable Future, Morris Animal Foundation, & the
American College of Veterinary Dermatology; T32 training grant
49
Still scratching your head?
[email protected]
Culture-Dependent Methods
Environmental Sampling
Animal Sampling
or
Salt broth
enrichment
PFGE & whole
genome analysis
(subset – pending)
or
PCR (nuc, mecA/C)
&
Antimicrobial
broth
enrichment
Columbia CNA
Blood Agar
(staph-selective)
Baird-Parker
Agar (CPS)
Antimicrobial
Susceptibility
Testing
Davis et al., Dry collection and culture methods for recovery of methicillin-susceptible and methicillin-resistant
Staphylococcus aureus strains from indoor home environments. Applied & Environmental Microbiology 2012.
Companion Animal Results: Baseline visit
PETS study prevalence, n (%)
MRSA
MSSA
MSSP1
13 (7%)
14 (8%)
31 (18%)
Dogs, n=71
5 (7%)
9 (13%)
27 (38%)1
Cats, n=63*
7 (11%)
4 (6%)
2 (3%)
Pocket pets, rabbit, ferret, n=11
0 (0%)
0 (0%)
0 (0%)
Reptiles, n=21
0 (0%)
1 (5%)
1 (5%)
Freshwater fish tanks, n=11
1 (9%)
0 (0%)
1 (9%)
Birds (parrots), n=2
0 (0%)
0 (0%)
0 (0%)
Pets overall, n=179*
Based on screening one isolate per pet per visit
Single S. schleiferi isolate identified (dog)
1Additional single MRSP isolate identified
* Five cats enrolled but not sampled, results based on prevalence among sampled pets
52
Companion Animal Risk Factor Analysis
MSSP
• Dogs were 19 times more likely than cats to be positive for S.
pseudintermedius (p=0.001).
• Owner-reported history of licking by pet was associated with a 4fold increase in odds of S. pseudintermedius positivity (p<0.001),
but this was largely explained by pet species (dog).
• Residence in suburban or rural area was associated with 4-fold
increase in odds for pet S. pseudintermedius positivity (p<0.01).
Logistic regression modeling, controlled for clustering at the household level
Bivariate ORs reported; these remained generally consistent in multivariate models
53
Companion Animal Results: Follow-up visit
PETS study
MRSA
MSSA
MSSP1
7 (5%)
12 (9%)
19 (15%)
Dogs, n=38
4 (11%)
5 (13%)
18 (45%)
Cats, n=48*
3 (6%)
7 (15%)
1 (2%)
Pocket pets, rabbit, ferret, n=9
0 (0%)
0 (0%)
0 (0%)
Reptiles, n=18
0 (0%)
0 (0%)
0 (0%)
Freshwater fish tanks, n=13
0 (0%)
0 (0%)
0 (0%)
Birds (parrots), n=2
0 (0%)
0 (0%)
0 (0%)
Pets overall, n=128*
Based on screening one isolate per pet per visit, n=130
1Additional single MRSP isolate identified (same pet positive at baseline)
*Two cats surveyed but not sampled, results based on prevalence among sampled pets
54
Companion Animal Results: Follow-up visit
PETS study
MRSA
MSSA
MSSP1
7 (5%)
12 (9%)
19 (15%)
Dogs, n=38
4 (11%)
5 (13%)
18 (45%)
Cats, n=48*
3 (6%)
7 (15%)
1 (2%)
Pocket pets, rabbit, ferret, n=9
0 (0%)
0 (0%)
0 (0%)
Reptiles, n=18
0 (0%)
0 (0%)
0 (0%)
Freshwater fish tanks, n=13
0 (0%)
0 (0%)
0 (0%)
Birds (parrots), n=2
0 (0%)
0 (0%)
0 (0%)
Pets overall, n=128*
Persistently positive pets (from 111 pets sampled longitudinally):
MRSA, 3%: 2 cats, 1 dog
MSSA, 3%: 2 cats, 1 dog
MSSP, 10%: 10 dogs, 1 cat
MRSP, 1%: 1 dog
55
Effect of Baseline Characteristics
and Household Randomization to Treatment
on Pet MRSA Status at Follow-up
Bivariate OR [95% CI]
Multivariate OR [95% CI]
Pet Positive at Baseline
15 [2.4, 89]
23 [1.8, 303]
Environment Positive at
Baseline
3.8 [0.42, 35]
2.0 [0.12, 34]
Proportion of MRSApositive People at
Baseline
3.6 [0.37, 34]
7.0 [ 0.19, 254]
Randomization to
Treatment Group
2.4 [0.40, 14]
3.5 [0.43, 28]
Decolonization treatment of people (2/3 of homes)
~3 months
Baseline
56
Follow-up
Effect of Baseline Characteristics
and Household Randomization to Treatment
on Pet MRSA Status at Follow-up
Bivariate OR [95% CI]
Multivariate OR [95% CI]
Pet Positive at Baseline
15 [2.4, 89]
23 [1.8, 303]
Environment Positive at
Baseline
3.8 [0.42, 35]
2.0 [0.12, 34]
Proportion of MRSApositive People at
Baseline
3.6 [0.37, 34]
7.0 [ 0.19, 254]
Randomization to
Treatment Group
2.4 [0.40, 14]
3.5 [0.43, 28]
Household randomization to treatment of people did not decrease odds of
pet MRSA positivity at the follow-up visit.
57
True colonization?
• Pets with persistent positivity: 15/113 (13%)
–
–
–
–
MRSA: 2 cats, 1 dog
MSSA: 2 cats, 1 dog
MSSP: 1 cat, 7 dogs
MRSP, 1 dog
• 3 dogs had MSSP-positive skin lesions at both visits
• Pets with mixed/shifting patterns over time: 6/113 (5%)
– MRSA to MSSA: 1 cat, 1 dog
– MRSA to MSSP: 2 dogs
– MSSS to MRSA: 1 dog
• This dog also had MSSP-positive FAD at baseline visit
– MSSP to MSSA: 1 dog
58
Clinical implications: susceptibility
Prevalence of multidrug resistance
Baseline visit
Follow-up visit
Pets
Env
Pets
Env
MRSA
38%
58%
86%
44%
MSSA
21%
6%
9%
37%
MRSP*
100%
-
-
-
MSSP
0%
0%
0%
0%
MSSS*
0%
-
-
-
*Single isolate from pet
59
PETS Enrollment & Microbiome Study
PETS study
Microbiome sub-study
Baseline
Follow-up
Baseline
Follow-up
95
65
25
21
67 (71%)
44 (68%)
22 (88%)
18 (86%)
Pets enrolled, N
184
1303
63
434
Dogs, N (%)
71 (39%)
38 (29%)
36 (57%)
19 (44%)
Cats, N (%)
68 (37%)
50 (38%)
20 (32%)
18 (42%)
Pocket pets, N (%)1
11 (6%)
9 (7%)
7 (11%)
6 (14%)
Reptiles, N (%)2
21 (11%)
18 (14%)
excluded
excluded
Freshwater fish tanks, N (%)
11 (6%)
13 (10%)
excluded
excluded
Birds (parrots), N (%)
2 (1%)
2 (2%)
excluded
excluded
Households enrolled, N
Homes with pets, N (%)
1 Chinchillas,
hamsters, rat, sugar glider,
ferret, rabbit
2 Turtles (primarily aquatic), lizards, snake
60
3 113
continuing pets, 17 new pets at followup (10 cats, 3 reptiles, 3 fish, and a hamster)
4 38 continuing pets, 5 new pets at follow-up
Preliminary PCR Results: Baseline visit
PETS study
Microbiome sub-study
MRSA
MSSA
MSSP1
MRSA
MSSA
MSSP1
13 (7%)
14 (8%)
27 (15%)
5 (8%)
4 (6%)
16 (25%)
Dogs
4 (6%)
9 (13%)
23
(32%)1
3 (8%)
2 (6%)
16 (44%)
Cats
8 (12%)
4 (6%)
2 (3%)
2 (10%)
2 (10%)
0 (0%)
Pocket pets
0 (0%)
0 (0%)
0 (0%)
0 (0%)
0 (0%)
0 (0%)
Reptiles
0 (0%)
1 (5%)
1 (5%)
excluded
excluded
excluded
Freshwater fish tanks
1 (9%)
0 (0%)
1 (9%)
excluded
excluded
excluded
Birds (parrots)
0 (0%)
0 (0%)
0 (0%)
excluded
excluded
excluded
Pets overall, N (%)
Based on screening one isolate per pet per visit (**underestimate of prevalence)
Single S. schleiferi isolate identified in an mbiome-sampled dog
1Additional single MRSP isolate in an mbiome-sampled dog
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Future Directions
• Planned completion of genetic analysis
– Finish PCR speciation (all isolates at nares/mouth mbiome sites)
– PFGE typing to evaluate clonality within households (incl. people and
environmental surfaces) and within pets over time
– Movement of genes, e.g. for antimicrobial resistance (including
SCCmec), between microbes within households and over time
• Molecular epidemiology / multilevel modeling
– Pets: do certain characteristics or behaviors predict MRSA positivity?
– RCT: do environmental contamination and pet colonization with MRSA
(independently or interactively) predict re-colonization of people after
successful decolonization treatment?
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