“…(2) A study carried out by Zettler et al in five hospitals in the city of Porto Alegre and published in this issue of the Brazilian Journal of Pulmonology (3) revealed that 5.2% of the pneumococcal strains isolated were resistant to erythromycin, a value similar to the 4.3% found among samples isolated in three Brazilian states from 1990 to 1999. (4) The two mechanisms of resistance found were alteration in the bacterial ribosome, with a decrease in the affinity for antimicrobials (MSLB phenotype), and alteration in the active efflux, in order to remove drugs from the cytoplasm of the microorganism (M phenotype).…”