BACKGROUND: The aim of this study was to know the antibiotic resistence of Streptococcus pyogenes to erythromycine, clindamycine and/or tetracycline in community samples. The second aim was to determine the existence of multiresistant strains and to know the relationship between resistant strains, clinical samples and age of the patient. METHOD: A retrospective analysis was performed in all the strains of S. pyogenes isolated from January 1992 to December 1994. Antibiotic sensitivity was studied by MIC by the microdilution method using the Pasco semiautomatic system. RESULTS: During the study period 573 beta hemolytic streptococci were identified as S. pyogenes. The global resistance to erythromycine (2.8%), clindamycine (1.4%) and tetracycline (7.3%) remains at low levels but has significantly increased in the case of erythromycine (p < 0.05) and tetracycline (p < 0.05) over these 3 years. The incidence of strains resistant to clindamycine has also increased slowly although this rise is not significant. Five strains (0.9%) were not sensitive to the three antibiotics studied, 4 being isolated in the last trimester of 1994 in pharyngeal exudates. S. pyogenes resistant to erythromycine was most frequently isolated from cutaneous lesions and in pediatric patients (under the age of 14 years). CONCLUSIONS: These results confirm the trend towards an increase in the number of strains of S. pyogenes resistant to erythromycine, clindamycine and/or tetracycline, being most often found in cutaneous lesions and pediatric patients.
BACKGROUND: The aim of this study was to know the antibiotic resistence of Streptococcus pyogenes to erythromycine, clindamycine and/or tetracycline in community samples. The second aim was to determine the existence of multiresistant strains and to know the relationship between resistant strains, clinical samples and age of the patient. METHOD: A retrospective analysis was performed in all the strains of S. pyogenes isolated from January 1992 to December 1994. Antibiotic sensitivity was studied by MIC by the microdilution method using the Pasco semiautomatic system. RESULTS: During the study period 573 beta hemolytic streptococci were identified as S. pyogenes. The global resistance to erythromycine (2.8%), clindamycine (1.4%) and tetracycline (7.3%) remains at low levels but has significantly increased in the case of erythromycine (p < 0.05) and tetracycline (p < 0.05) over these 3 years. The incidence of strains resistant to clindamycine has also increased slowly although this rise is not significant. Five strains (0.9%) were not sensitive to the three antibiotics studied, 4 being isolated in the last trimester of 1994 in pharyngeal exudates. S. pyogenes resistant to erythromycine was most frequently isolated from cutaneous lesions and in pediatric patients (under the age of 14 years). CONCLUSIONS: These results confirm the trend towards an increase in the number of strains of S. pyogenes resistant to erythromycine, clindamycine and/or tetracycline, being most often found in cutaneous lesions and pediatric patients.