During year 6 (2005-2006) of the Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin surveillance study, 6,747 Streptococcus pneumoniae isolates were collected at 119 centers. The susceptibility of these isolates to macrolides was compared with data from previous years. Macrolide resistance increased significantly in year 6 (35.3%) from the stable rate of app...

The genetic basis of macrolide resistance in Campylobacter coli (n = 17) and C. jejuni (n = 35) isolates previously subjected to in vivo selective pressure was investigated to determine if the number of copies of 23S rRNA genes with macrolide-associated mutations affects the minimum inhibitory concentration (MIC) of macrolides. Sequence data for domain V of the 23S rRNA gene revealed that two m...

BACKGROUND Many patients hospitalized with pneumonia are treated with combination macrolide/cephalosporin therapy. Macrolides have immunomodulatory effects and do not directly cause bacterial lysis. These effects suggest the possibility that initial treatment with a macrolide before a cephalosporin could improve patient outcomes by preventing the inflammatory response to rapid bacterial lysis t...

Mycoplasma pneumoniae is a major pathogen causing community-acquired pneumoniae (CAP), which is generally treated with macrolides. In recent years, however, although macrolide-resistant M. pneumoniae has been reported frequently, particularly in China, very little is known about the prevalence of macrolide-resistant M. pneumoniae infection in adults. In this study, we survey the macrolide-resis...

We correlated outpatient antibiotic use with prevalence of penicillin-nonsusceptible Streptococcus pneumoniae (PNSP), macrolide-resistant S. pneumoniae (MRSP), and macrolide-resistant S. pyogenes (MRGAS) in 20 countries. Total antibiotic use was correlated with PNSP (r = 0.75; p < 0.001), as was macrolide use with MRSP (r = 0.88; p < 0.001) and MRGAS (r = 0.71; p = 0.004). Streptococcal resista...

CONTEXT Macrolide antibiotics, including erythromycin, clarithromycin, and azithromycin, are the mainstays of empirical pneumonia therapy. Macrolide resistance among Streptococcus pneumoniae, the most common cause of community-acquired pneumonia, is increasing in the United States. Whether resistance is a significant problem or whether macrolides remain useful for treatment of most resistant st...

[reaction: see text] A novel ring opening ring closing metathesis (ROM-RCM) was demonstrated for cyclic conjugated dienes, effecting the excision of a C(2)H(2) unit and a net ring contraction. Applying the ring contraction metathesis, new 14-membered ring macrolide antibiotics were synthesized in a single step from existing 16-membered ring macrolides. This new class of macrolide antibiotics wi...

Eighty percent (21 of 26) of macrolide-resistant Peptostreptococcus strains studied harbored the ermTR gene. This methyltransferase gene is also the most frequently found gene among macrolide-lincosamide-streptogramin B-resistant Streptococcus pyogenes strains. Transfer of the ermTR gene from Peptostreptococcus magnus to macrolide-susceptible S. pyogenes strains indicates that this resistance d...