Table 2.

Selected Studies on Potential Transmission of Pathogens between Humans and Animals in Various Settings

Organism	Comments	Reference
Ecological
MRSA	MRSA strains found in companion animals such as dogs and cats are identical to epidemic strains found in human hospitals	[89]
MRSA	Resistance patterns and genetic make-up of MRSA isolates from dogs and cats are generally indistinguishable from the most prevalent hospital-associated MRSA strains in the human population	[90]
MRSA	Increase in companion animal MRSA, including MDRO, same clonal lines as CA&HA-MRSA	[91]
MRSA	Phylogenomic analyses showed that companion animal isolates were interspersed throughout the epidemic MRSA pandemic clade and clustered with human isolates from the United Kingdom suggesting a human source for isolates infecting companion animals	[92]
Pet Ownership
MRSA	Transmission of MRSA occurs between humans and companion animals and vice versa	[93]
MRSA	Identification of indistinguishable MRSA isolates in both pets and humans in contact with them	[94]
MRSA	MRSA was found in pets from MRSA-positive owners in 4/49 (8.2%) vs. none of the pets of the 50 uninfected human controls. ¾ of these pairs had concordant PFGE pattern	[95]
MRSA	MRSA-infected animal was initially identified, at least one MRSA-colonized person was identified in over one-quarter (6/22; 27.3%) of the study households. By contrast, only one of the 8 (12.5%) study households of MRSA-infected humans contained a MRSA- colonized pet	[96]
Enterococcus	76% of the isolates from companion dogs had belonged to hospital-adapted clonal complex, screening of 18 healthy humans living in contact with 13 of the dogs under study resulted in the identification of a single, intermittent carrier. This person carried one of the sequence types recovered from his dog	[97]
MRSA	Identical strains from both pets and their owners were identified. Typical livestock-associated S. aureus lineages were observed in humans and/or companion animals and hospital and/or community-acquired S. aureus lineages were detected among pets.	[98]
C. difficile	PFGE patterns of some dog and human C. difficile isolates were over 90% similar	[99]
Livestock
MRSA	373 (9.7%) patients coming from a high-density farming area were positive for MRSA, 292 (78%) had livestock-associated MRSA strains and 81 (22%) non-LA-MRSA strains	[100]
MRSA	Patients exposed to pigs or veal calves were shown to have 3 times higher incidence of MRSA colonization	[101]
MRSA	MRSA carriage in HCWs in contact with livestock is 10-fold higher than in other HCWs	[102]
Hospital
MRSA	Dog was implicated as a reservoir for the re-infection of two nurses after their treatment to eliminate carriage of MRSA	[103]
MRSA	Cat residing in a geriatric rehabilitation ward was implicated as the source of MRSA for nurses and patients	[104]
MRSA, C. difficile	Zoonotic agents were isolated from 80 out of 102 (80%) dogs who visit hospitals, primary pathogen was Clostridium [sic] difficile, which was isolated from 58 (58%) fecal specimens, Seventy-one percent (41/58) of these isolates were toxigenic	[105]
MRSA	Acquisition of MRSA by a pet therapy dog that had visited an elderly care ward in a healthcare facility	[106]
MRSA, C. difficile	Rates of acquisition of MRSA and C. difficile were 4.7 and 2.4 times as high, respectively, among dogs that visited human health-care facilities, C.diff 4% was toxigenic, MRSA hospital origin clone	[107]
C. difficile	Canine fecal isolate from healthy dog who visits hospitals was indistinguishable from the major strain implicated in outbreaks of highly virulent CDAD, which were occurring at increased frequency in the facility around the time the dog’s fecal specimen was collected	[108]
Veterinary Hospitals
MRSA	Cluster of five canine postoperative wound cases infected with MRSA were found to be associated with asymptomatic carriage of MRSA in one of the attending veterinary surgeons. The human and canine isolates were corresponded to the predominant epidemic strain prevalent in hospitals at this time	[109]
MRSA	MRSA was isolated from 16% (14/88) of household contacts or veterinary personnel and in all 6 identified cases at least one human isolate identical to the initial animal isolate was found.	[110]
MRSA	Comparison of genetic markers shows that identical or very similar strains disseminate among animals and veterinary personnel. Companion animals harbor PVL-positive clones - Twenty-six pets and five veterinary personnel carried PVL-positive S. aureus	[111]
MR Staph	Risk factors for nasal colonization by MRS in healthy humans: (i) being a veterinary professional (veterinarian and veterinary nurse) (p < 0.0001, odds ratio [OR] = 6.369, 95% confidence interval [CI, 2.683–15.122]), or have contacted with one MRSA- or MRSP-positive animal (p = 0.0361, OR = 2.742, 95% CI [1.067–7.045]	[112]
MRSA	One veterinary nurse, who carried Panton Valentine leucocidin-positive ST338 MRSA, also owned a ST749 MRSP-positive dog	[113]
MRSA	MRSA was isolated from 14 staff (17.9%), four dogs (9%), and three environmental sites (10%), which all had the same PFGE pattern.	[114]

MRSA methicillin-resistant Staphylococcus aureus, C. difficile Clostridioides difficile, HCW healthcare worker