[Staphylococcus aureus septicemia in children: bacterial tolerance to vancomycin and serum bactericidal activity]

To evaluate the susceptibility and of strains of Staphylococcus aureus isolated from children with septicemia, and to evaluate the importance of the serum bactericidal test.

Seventeen children with Staphylococcus aureus septicemia admitted to the Semi Intensive Care Unit of the Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo were studied. Twenty nine tests in the pico and 23 in the nadir of the antibiotics were made.

Strains of Staphylococcus aureus from hospital origin were resistant to all the antibiotics but vancomycin and pefloxacin. The phenomenon of tolerance was seen in 5 (50%) of the strains that were tested for vancomycin, and 4 of the children had a bad evolution. The serum bactericidal tests showed titles in the pico > or = 1/8 in 55.5% of the observations; in this group the evolution was better.

Strain of Staphylococcus aureus from hospital origin are multiresistant. The phenomenon of antimicrobial tolerance, as well as the serum bactericidal test may be related to a bad therapeutic evolution. The increasing value of the serum bactericidal test as a way to evaluate the therapeutic evolution in severe infections, and the role of the tolerance of the Staphylococcus aureus to vancomycin more studies.