Antimicrobial resistance of 914 beta-hemolytic streptococci isolated from pharyngeal swabs in Spain: Results of a 1-year (1996-1997) multicenter surveillance study

A nationwide susceptibility surveillance study of beta-hemolytic streptococ cal isolates from pharyngeal swabs obtained in 11panish hospitals between M ay 1996 and April 1997 against 12 antibiotics was carried out. Of the isola tes 86% (786 of 914 isolates) were group A and 8.4% (77 of 914 isolates) we re group C. No resistance was found to beta-lactam antibiotics, but signifi cant differences (P < 0.001) with respect to lack of susceptibility to macr olides were found between groups (27% for group ii and 12% for group C) and between seasons (13.2% in summer and 31.7% in winter). Most of these isola tes displayed the hf phenotype (low-level resistance to erythromycin and su sceptibility to clindamycin).