[Activity of erythromycin and clarithromicin against isolates of Streptococcus pneumoniae with decreased sensitivity to penicillin obtained from healty carriers. Spanish Collaborative Group].

BACKGROUND

Empirical treatment of pneumococcal upper and lower respiratory infections must be chosen on the basis of the susceptibility patterns of nasopharyngeal colonizing strains isolated from healthy carriers.

METHODS

The susceptibility to erythromycin and clarithromycin was investigated by a conventional microdilution method among 103 pneumococci isolates recovered from healthy children (n = 63) and adults (n = 40) exhibiting decreased susceptibility to penicillin (MIC > or = 0.12 mg/l).

RESULTS

63% of penicillin -resistant pediatric isolates were susceptible to erythromycin and 78.9% were susceptible to clarithromycin . Among isolates with diminished susceptibility to penicillin , 77.7% were susceptible to erythromycin and 86.3% to clarithromycin . 90% of adult isolates were susceptible to erythromycin and to clarithromycin . Overall, clarithromycin exhibited a better activity than erythromycin .

CONCLUSIONS

Clarithromycin , and to a lesser extent erythromycin , are good alternatives to penicillin in the empirical treatment of respiratory tract infections caused by pneumococci with diminished susceptibility to penicillin .