Nationwide German multicenter study on the prevalence of antibiotic resistance in streptococcal blood isolates from neutropenic patients and comparative in vitro activities of quinupristin-dalfopristin and eight ether antimicrobials

In a prospective multicenter study (1996 to 1999), 156 episodes of bacterem ic streptococcal infections of neutropenic patients were evaluated. Strepto coccus oralis (26.3%), S, pneumoniae (26.3%), S, agalactiae (11.5%), s, mit is (9%), and S. pyogenes (5.8%) were the predominant species. Four strains (2.6%) were found to be intermediately resistant to penicillin. One strain (0.6%) was found to be highly resistant to penicillin (MIC, 8 mg/liter), Re duced susceptibility to penicillin was detected among S, oralis (14.6%), S. mitis (7.1%), and S. pneumoniae (4.9%) isolates but was not recorded among S, agalactiae and S, pyogenes. Resistance rates and intermediate resistanc e rates for other antimicrobials were as follows tall species): amoxicillin . 1.3 and 3.2% erythromycin, 16 and 2.6%: clindamycin, 5.8 and 0%; ciproflo xacin, 1.9 and 7.7%. Quinupristin-dalfopristin showed goad in vitro activit y against most streptococcal isolates (MIC: at which 50% of the isolates we re inhibited [MIC50], 0.5 mg/liter; MIC90, 1 mg/liter, MIC range, 0.25 to 4 mg/liter).