Clinically overt infections with methicillin-resistant Staphylococcus aureus in animals in New Zealand: a pilot study.
OBJECTIVE
To describe clinically overt infections with methicillin resistant Staphylococcus aureus (MRSA) in animals in New Zealand, characterise clinical isolates, and track their sources.


METHODS
MRSA isolates identified in 2005 and 2006 by a veterinary diagnostic laboratory were referred to Massey University for confirmation and characterisation. Clinical information was extracted from the laboratory records or obtained from referring clinicians.


RESULTS
Seven MRSA isolates from animals and contact persons were characterised. All the isolates belonged to the British epidemic MRSA 15 strain (EMRSA-15). Three EMRSA-15 were isolated from post-operative infections in two dogs. An EMRSA-15 indistinguishable from the isolate recovered from one dog was isolated from the anterior nares of a healthy hospital staff member involved in the care of the animal, suggesting nosocomial transmission. Other EMRSA-15 isolates of uncertain clinical significance were isolated from the femoral head of a cat, and from a sample of cow's milk. AlleMRSA-15 isolates were resistant to ciprofloxacin, and four were resistant to erythromycin; the latter four isolates also exhibited inducible resistance to clindamycin.


CONCLUSIONS
MRSA can cause clinically overt and difficult-to-treat infections in animals in New Zealand. The rapid emergence of EMRSA-15 as the dominant MRSA strain in humans has resulted in infection spill over to animals.


CONCLUSIONS
Little is known about the incidence of clinically overt infections with MRSA in animals. The cases described here illustrate the complexities involved in the pharmacological management of EMRSA-15 infections, which is compounded by the universal resistance to beta-lactams, and by the strain's fluoroquinolone resistance and frequent inducible resistance to clindamycin. Such complexities indicate there is a need to develop specific empirical antimicrobial treatment strategies and antibiotic susceptibility testing protocols in countries where EMRSA-15 is dominant.
Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, New Zealand. a.grinberg@massey.ac.nz
A
A
Grinberg
D D
DD
Kingsbury
I R
IR
Gibson
B M
BM
Kirby
H J
HJ
Mack
D
D
Morrison
D017750:Animal Technicians; D000818:Animals; D002353:Carrier State / Q000382:microbiology; D002415:Cats; D002417:Cattle; D003428:Cross Infection / Q000662:veterinary; D004285:Dogs; D006736:Horses; D006762:Hospitals, Animal; D006801:Humans; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000472:pathogenicity*; D009520:New Zealand; D010802:Phylogeny; D010865:Pilot Projects; D011183:Postoperative Complications / Q000662:veterinary; D013203:Staphylococcal Infections / Q000382:microbiology / Q000473:pathology / Q000635:transmission* / Q000662:veterinary*; D015047:Zoonoses