Human-to-Dog Transmission of Methicillin-Resistant Staphylococcus aureus
Engeline van Duijkeren,*Comments Maurice J.H.M. Wolfhagen,† Adrienne T.A. Box,‡ Max E.O.C. Heck,� Wim J.B. Wannet,� and Ad C. Fluit‡
*Faculty of Veterinary Medicine, Utrecht, the Netherlands; †Isala Clinics, Zwolle, the Netherlands; ‡University Medical Center Utrecht, Utrecht; the Netherlands; and �National Institute of Public Health and the Environment, Bilthoven, the Netherlands
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Methicillin-resistant Staphylococcus aureus (MRSA) was cultured from the nose of a healthy dog whose owner was colonized with MRSA while she worked in a Dutch nursing home. Pulsed-field gel electrophoresis and typing of the staphylococcal chromosome cassette mec (SCCmec) region showed that both MRSA strains were identical.
In 2000, a methicillin-resistant Staphylococcal aureus (MRSA) strain was isolated from a patient admitted to a multisite 1,100-bed tertiary-care teaching hospital in the Netherlands. This strain recurred during several outbreaks and spread to a 190-bed nursing home, which is part of the hospital. During a large outbreak in 2003 in the nursing home, 48 patients and 15 nurses were identified as carriers of MRSA, either in their nares, throat, perineum, or a combination of these sites. All MRSA isolates from the outbreaks were sent to the National Institute of Public Health and the Environment (RIVM) for identification and genotyping by pulsed-field gel electrophoresis (PFGE). Most MRSA had the same PFGE pattern, RIVM cluster 35.
In 2003, a 31-year-old female nurse who had psoriasis was identified as an MRSA carrier during the above-mentioned MRSA outbreak. The nurse was treated to eliminate MRSA carriage by applying mupirocin ointment in her nares and washing with a chlorhexidine in ethanol solution for 7 days. Initially she became MRSA-negative but later converted to a carrier state again: samples from her nose, throat, perineum, and skin lesions were taken, and MRSA could be isolated from all sites. She was treated for her psoriasis with topical application of triamcinolonacetonide/tetracycline to minimize the skin lesions and thereafter with oral doxycycline and rifampin to eliminate MRSA. However, after some weeks, she became colonized again at all previously mentioned sites. Screening her home environment showed that her 1-year-old daughter, who also had psoriasis, was colonized in the nose, throat, and skin lesions. The nares, but not the perineum, of their healthy pet dog were also colonized. The dog had not been treated with antimicrobial drugs in the past. Samples from nose, throat, and perineum from the patient's husband were MRSA negative, as were samples from nose, throat, perineum, and skin lesions of the baby's grandmother, who also had psoriasis and took care of the baby when the mother worked.