In vitro activities of garenoxacin and levofloxacin against Chlamydia pneumoniae are not affected by presence of Mycoplasma DNA.
We studied 20 Chlamydia pneumoniae isolates obtained from respiratory sites and atheroma tissue of patients from various geographic areas to determine the susceptibilities of these isolates to a new des-fluoroquinolone, garenoxacin, and to levofloxacin. In addition, we assessed the cultures with these isolates by PCR for the presence or absence of Mycoplasma sp. DNA. Both the MIC at which 90% of isolates are inhibited (MIC(90)) and the minimal bactericidal concentration at which 90% of isolates are killed (MBC(90)) for garenoxacin were 0.06 microg/ml, and both the MIC(90) and the MBC(90) for levofloxacin were 2.0 microg/ml. The activity of garenoxacin against C. pneumoniae was 32-fold greater than that of levofloxacin. Mycoplasma sp. DNA was detected by PCR in 17 of 20 cultures. Mycoplasma amplicons from five Mycoplasma DNA-positive C. pneumoniae cultures were sequenced and found to represent four Mycoplasma species. Our data demonstrate that C. pneumoniae cultures frequently contain Mycoplasma DNA and that its presence in C. pneumoniae cultures does not appear to affect the susceptibility results for the two fluoroquinolones that we tested.
Smith
Raymond P
RP
Stratton Veterans Affairs Medical Center, New York State Department of Health, Albany, NY 12208, USA.
Baltch
Aldona L
AL
Ritz
William J
WJ
Carpenter
Andrea N
AN
Halse
Tanya A
TA
Bopp
Lawrence H
LH
D000890:Anti-Infective Agents / Q000494:pharmacology*; D002690:Chlamydia Infections / Q000382:microbiology; D016993:Chlamydophila pneumoniae / Q000187:drug effects*; D004269:DNA, Bacterial / Q000235:genetics*; D030541:Databases, Genetic; D024841:Fluoroquinolones / Q000494:pharmacology*; D006801:Humans; D064704:Levofloxacin; D008826:Microbial Sensitivity Tests; D009174:Mycoplasma / Q000235:genetics*; D015242:Ofloxacin / Q000494:pharmacology*; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000890:Anti-Infective Agents; D004269:DNA, Bacterial; D024841:Fluoroquinolones; D012336:RNA, Ribosomal, 16S; D064704:Levofloxacin; D015242:Ofloxacin; C419689:garenoxacin