Significant decline in the erythromycin resistance of group A streptococcus isolates at a German paediatric tertiary care centre.

Group A streptococcus (GAS) is considered to be a major pathogen of bacterial tonsillopharyngitis in children. Although GAS is generally susceptible to penicillin, macrolides are often used as the second-line treatment. Over the last several decades, the rising macrolide resistance of GAS has been detected in several countries. With the current study, we aimed to determine the development of macrolide resistance at our paediatric centre. From March 2006 to May 2009, 350 GAS isolates were tested for susceptibility to erythromycin, azithromycin, clindamycin, penicillin and cefotaxime. Macrolide-resistant isolates were screened for the presence of genes related to macrolide resistance (mefA, ermB, ermTR, prtF1). In comparison to a prior study at our hospital, the erythromycin resistance rate decreased significantly from 13.6 to 2.6%. This effect may be attributable to a more restrictive use of macrolides in children in our region.