Staphylococcus aureus isolados da nasofaringe de crianças que frequentam creches no município de Goiânia-GO: prevalência de colonização, suscetibilidade antimicrobiana e fatores de virulência

Abstract

Staphylococcus aureus is one of the most important human pathogens, accounting for infectious diseases that can range from simple infections to serious complications such as meningitis and sepsis, reaching tod eath. S. aureus naturally colonizes the human anterior nostril and has a high spreading power, which may be potentiated according to some external factors, such as the case of children attending day care centers. The aim of this study was to determine the prevalence of S. aureus colonization in children between 36 and 59 months, the profile of antimicrobial susceptibility and to detect virulence factors in the isolated bacteria. From October to December 2010, swabs of nasal secretion from children in 59 Municipal Centers of Early Childhood Education were collected in the city of Goiânia, Goiás The samples were sent to the Laboratory of Applied Bacteriology of Tropical Pathology and Public Health at the Federal University of Goias for processing. The isolation was performed by standardized methodology. The conventional PCR was used for detection of femA (identification of the species) and mecA and lukS-F genes (virulence factors). The susceptibility profile was determined by disk diffusion and Etest® method. In total, 1,135 swabs were collected. A prevalence of 30.7% (348 isolates) was achieved for S. aureus. Through the antimicrobial susceptibility test, isolates showed resistance to the following antimicrobials: penicillin (94.5%), quinupristin / dalfopristin (35.6%), erythromycin (34.1%), clindamycin (28.6%), sulfamethoxazole / trimethoprim (9.9%), tetracycline (6.1%), ciprofloxacin (4.7%), cefoxitin (3.5%) and rifampicin (0.9%). The MLSb phenotype was detected em 93 isolates (27.1%). Among the 12 isolates resistant to cefoxitin, five (0.44%) presented the mecA gene, characterized as MRSA. The multidrug resistance profile was identified in 107 isolates (31.2%). Gene lukS-F was found in 26 isolates (7.5%). The results showed that the prevalence of S. aureus and MRSA colonization in children at this age remain constant compared to previous studies. However, the multidrug resistance that was found in 1⁄4 of the isolates and the detection of the gene that encodes the PVL are cause for concern because represent difficulty of treatment, increased virulence and risk of dissemination in the community that the daycare environment provides.