Related Experiment Videos
[Sensitivity of group A beta-hemolytic Streptococcus isolated from pediatric pharyngotonsillitis to erythromycin and
J García de Lomas1, C Gimeno, J Díez
1Departamento de Microbiología, Hospital Clínico Universitario y Facultad de Medicina, Valencia. jlomas@mx3.redestb.es
Background:
The recent increase in the prevalence of macrolide-resistant group A beta-haemolytic Streptococcus (BHSGA) strains reported in some areas in Spain and several neighboring countries underscores the need to perform a periodic surveillance, with the adequate methodology, of the level of its susceptibility to these antimicrobials which are frequently used in our country for the treatment of acute streptococcal pharingotonsillitis and respiratory tract infections.
Patients And Methods:
The susceptibility of 293 isolates of BHSGA to the macrolides erythromycin and clarithromycin was evaluated by the broth microdilution procedure recommended by the NCCLS (1997). The isolates were prospectively obtained from children with acute pharyngotonsillitis (n = 757) who were seen at primary care centers in ten Spanish cities.
Results:
An overall prevalence of 8.9 and 7.8% erythromycin- and clarithromycin-resistant BHSGA isolates was respectively found. The percentage of resistant isolates varied considerably among the different cities subjected to study (0-33%). Overall, the intrinsic activity of clarithromycin (MIC50 and MIC90 of 0.007 and 0.25 mg/ml, respectively) was slightly higher than that of erythromycin (MIC50 and MIC90 of 0.015 and 0.5 mg/ml, respectively). All strains studied were uniformly susceptible to penicillin.
Conclusions:
Macrolide antibiotics, erythromycin and clarithromycin, continue to be highly active against BHSGA. The mean level of resistant strains found in Spain from community acquired infections and recovered prospectively is comparable to that of our neighboring countries.