Marilyn C Roberts1, Olusegun O Soge2, Jeremy A Horst3, Kiet A Ly4, Peter Milgrom5. 1. Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA. Electronic address: marilynr@u.washington.edu. 2. Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA. 3. Department of Oral Biology, University of Washington, Seattle, WA. 4. Department of Dental Public Health Sciences, University of Washington, Seattle, WA. 5. Department of Dental Public Health Sciences, University of Washington, Seattle, WA; Northwest Center to Reduce Oral Health Disparities, School of Dentistry, University of Washington, Seattle, WA.
Abstract
BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) isolated from frequently touched dental school clinic surfaces were compared with MRSA isolated nasal cultures of dental students. METHOD: Sixty-one dental students and 95 environmental surfaces from 7 clinics were sampled using SANICULT (Starplex Scientific Inc, Etobicoke, Ontario, Canada) swabs. Antimicrobial susceptibility testing was performed, and pulsed-field gel electrophoresis analysis, the mecA gene, multilocus sequence type, and SCCmec type were determined by polymerase chain reaction and sequencing. RESULTS: Thirteen (21%) dental students and 8 (8.4%) surfaces were MRSA positive. Three MRSA strains were SCCmec type IV, whereas 3 were nontypeable isolates and Panton-Valentine leukocidin positive (PVL+), and none were USA300. One surface and 1 student isolate shared the same multilocus sequence type ST 8 and were 75% related. Two groups of students carried the same MRSA strains. CONCLUSION: The MRSA-positive samples were from 4 of 7 dental clinics. In addition, 21% of the dental students carried MRSA, which is > 10 times higher than the general public and twice as frequent as in other university students. This is the first study to characterize MRSA from dental clinic surfaces and dental students and suggests that both may be reservoirs for MRSA. Further studies are needed to verify this premise.
BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) isolated from frequently touched dental school clinic surfaces were compared with MRSA isolated nasal cultures of dental students. METHOD: Sixty-one dental students and 95 environmental surfaces from 7 clinics were sampled using SANICULT (Starplex Scientific Inc, Etobicoke, Ontario, Canada) swabs. Antimicrobial susceptibility testing was performed, and pulsed-field gel electrophoresis analysis, the mecA gene, multilocus sequence type, and SCCmec type were determined by polymerase chain reaction and sequencing. RESULTS: Thirteen (21%) dental students and 8 (8.4%) surfaces were MRSA positive. Three MRSA strains were SCCmec type IV, whereas 3 were nontypeable isolates and Panton-Valentine leukocidin positive (PVL+), and none were USA300. One surface and 1 student isolate shared the same multilocus sequence type ST 8 and were 75% related. Two groups of students carried the same MRSA strains. CONCLUSION: The MRSA-positive samples were from 4 of 7 dental clinics. In addition, 21% of the dental students carried MRSA, which is > 10 times higher than the general public and twice as frequent as in other university students. This is the first study to characterize MRSA from dental clinic surfaces and dental students and suggests that both may be reservoirs for MRSA. Further studies are needed to verify this premise.
Authors: Olusegun O Soge; David No; Karen E Michael; Jennifer Dankoff; Jennifer Lane; Keith Vogel; Jeremy Smedley; Marilyn C Roberts Journal: J Antimicrob Chemother Date: 2016-07-20 Impact factor: 5.790