Activity of the ketolide telithromycin (HMR-3647) against erythromycin-susceptible and -resistant pneumococci isolated in the UK.
The novel ketolide telithromycin (formerly HMR-3647) was tested against a collection of pneumococci of varying sensitivity to erythromycin and clindamycin, isolated in geographically diverse UK hospitals. Telithromycin was highly active against erythromycin-susceptible pneumococci, the MIC(90) being 0.015 mg/l. Erythromycin-resistant pneumococci that contained the ermB gene, either alone or together with the mefE gene, were cross-resistant to other macrolides and to clindamycin, while erythromycin-resistant pneumococci that contained only the mefE gene were cross-resistant to azithromycin, clarithromycin and roxithromycin but remained susceptible to josamycin and clindamycin. Telithromycin was active against erythromycin-resistant pneumococci irrespective of their mechanism of macrolide resistance, although the MIC(90) (0.25 mg/l) was higher than that seen with erythromycin-sensitive isolates. Telithromycin thus appears to be a potentially useful drug in settings where pneumococcal resistance to macrolides is prevalent.
Johnson
A P
AP
Antibiotic Resistance Monitoring and Reference Laboratory, Central Public Health Laboratory, Colindale, NW9 5HT, London, UK. ajohnson@phls.nhs.uk
Henwood
C J
CJ
Tysall
L
L
Warner
M
M
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000235:genetics; D002981:Clindamycin / Q000494:pharmacology; D004352:Drug Resistance, Microbial; D018432:Drug Resistance, Multiple; D004917:Erythromycin / Q000494:pharmacology*; D048628:Ketolides; D018942:Macrolides; D008565:Membrane Proteins; D008780:Methyltransferases / Q000235:genetics; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000235:genetics
D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D048628:Ketolides; D018942:Macrolides; C431304:MefE protein, Streptococcus pneumoniae; D008565:Membrane Proteins; D002981:Clindamycin; D004917:Erythromycin; D008780:Methyltransferases; C035181:rRNA (adenosine-O-2'-)methyltransferase; C106791:telithromycin