Susceptibility of penicillin-resistant and penicillin-susceptible Streptococcus pneumoniae to newer antimicrobial agents

Agar dilution minimum inhibitory concentration (MIC) methodology, according to NCCLS guidelines, was used to test the activity of three glycopeptides (LY 333328 [LY], vancomycin [VAN], and teicoplanin [TEI]), four fluoroquino lones (trovafloxacin [TRO], BAY 12-8039 [BAY], ciprofloxacin [CIP], and ofl oxacin [OFL]), five macrolide-lincosamide-streptogramin antibiotics (erythr omycin [ERY], azithromycin [AZI], miocamycin [MOM], clindamycin CLN], and q uinupristin-dalfopristin [SYN] against 126 Streptococcus pneumoniae strains , isolated in Lozano Blesa Hospital of Zaragoza (Spain). MIC50/MIC90 (mu g/ ml) values for penicillin-susceptible (PS), penicillin-intermediate (PI) an d penicillin-resistant (PR) strains show an excellent antipneumococcal acti vity of LY 333326-a new glycopeptide, for the fluoroquinolones trovafloxaci n and moxifloxacin [BAY 12-8039], and for quinupristin/dalfopristin, regard less of the resistance phenotype of the strains.