Isolation and antimicrobial resistance of Staphylococcus aureus isolates in a dental clinic environment.
OBJECTIVE
To determine the number of Staphylococcus aureus isolates collected in a dental clinical environment and to determine their susceptibility to antimicrobial agents commonly used in dentistry.


METHODS
Undergraduate clinic of the Dental School of Piracicaba, University of Campinas, Brazil.


METHODS
Sterile cotton swabs were used to collect the samples from dental-chair push buttons, light handles, 3-in-1 syringes, computer "Enter" keys, doorknobs, and X-ray tubes before, during, and after clinical procedures. These samples were spread on brain-heart infusion agar and were incubated at 37 degrees C for 24 hours. The resulting S. aureus isolates were counted and classified using Gram staining and biochemical tests. The counts among the 3 periods and the groups were analyzed by Kruskal-Wallis and Dunn tests (alpha =5%). Commercial paper disks containing widely prescribed antimicrobial agents (beta-lactams, macrolides, clindamycin, and vancomycin) were used to perform the antimicrobial susceptibility tests.


RESULTS
An increase in the number of microorganisms was observed during clinical procedures (P<.05). The highest bacterial resistance rates were observed for the beta -lactam group. All isolated strains were sensitive to vancomycin, and 2% of them were resistant to methicillin.


CONCLUSIONS
Clinical procedures increased the number and proportion of antimicrobial-resistant S. aureus isolates dispersed in a dental clinical environment. The present study highlights the need to establish strategies to prevent emergence of drug-resistant bacterial strains in dental settings.
Motta
Rogério Heládio Lopes
RH
Department of Physiologic Sciences, São Leopoldo Mandic, Campinas, Brazil. rogeriomotta@fop.unicamp.br
Groppo
Francisco Carlos
FC
Bergamaschi
Cristiane de Cássia
Cde C
Ramacciato
Juliana Cama
JC
Baglie
Sinvaldo
S
de Mattos-Filho
Thales Rocha
TR
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001938:Brazil; D003740:Dental Clinics; D024881:Drug Resistance, Bacterial; D016106:Methicillin Resistance; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification*; D014640:Vancomycin / Q000494:pharmacology; D018440:beta-Lactam Resistance
D000900:Anti-Bacterial Agents; D014640:Vancomycin