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Comparative in vitro activity of telithromycin against macrolide-resistant and -susceptible Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae.
J Antimicrob Chemother. 2004 May; 53(5):793-6.JA

Abstract

OBJECTIVES

The first objective was to investigate the in vitro activity of telithromycin against respiratory tract pathogens in comparison with other antimicrobial agents. The second objective was to identify the influence of the erm(B) and mef(A) genes on the susceptibility of Streptococcus pneumoniae to telithromycin.

METHODS

The in vitro activity of telithromycin against S. pneumoniae, Moraxella catarrhalis and Haemophilus influenzae, isolated from the UK and 40 macrolide-resistant S. pneumoniae from four different countries was compared with a variety of antimicrobial agents. The 140 isolates were examined for the presence of the erm(B) and mef(A) genes. The impact of 5% CO(2) on susceptibility testing was also investigated.

RESULTS

Telithromycin showed greatest activity against S. pneumoniae, but also had good activity against M. catarrhalis and H. influenzae, which was independent of their resistance profiles to other antibiotics. The MIC(90) of telithromycin for S. pneumoniae was 0.12 mg/L, which was 64-fold lower than the lowest macrolide MIC; 21% of the S. pneumoniae were macrolide resistant. Thirty-eight per cent of the macrolide-resistant strains were erm(B)-positive and 62% were mef(A)-positive, but no strain contained both genes. The activity of telithromycin was similar to that of azithromycin against both M. catarrhalis and H. influenzae, Erythromycin was slightly less active: 1% and 8% of M. catarrhalis and H. influenzae, respectively, were resistant to erythromycin, but none were resistant to telithromycin. Five per cent of the S. pneumoniae strains and 4% of the H. influenzae strains changed from telithromycin susceptible to non-susceptible entirely because of the incubation conditions. The MIC(50)s and MIC(90)s of S. pneumoniae, M. catarrhalis and H. influenzae increased by one dilution when incubated in CO(2).

CONCLUSIONS

Telithromycin has shown high in vitro activity against S. pneumoniae, including those strains that are macrolide susceptible and resistant as well as M. catarrhalis and H. influenzae. This study has also demonstrated that there is no cross-resistance between erythromycin and telithromycin. The impact of 5% CO(2) on susceptibility testing should be investigated further before providing definite guidelines on telithromycin susceptibility testing.

Authors+Show Affiliations

Department of Medical Microbiology, Medical School, University of Edinburgh, Edinburgh EH8 9AG, UK. fwalsh@staffmail.ed.ac.ukNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15056640

Citation

Walsh, Fiona, et al. "Comparative in Vitro Activity of Telithromycin Against Macrolide-resistant and -susceptible Streptococcus Pneumoniae, Moraxella Catarrhalis and Haemophilus Influenzae." The Journal of Antimicrobial Chemotherapy, vol. 53, no. 5, 2004, pp. 793-6.
Walsh F, Carnegy F, Willcock J, et al. Comparative in vitro activity of telithromycin against macrolide-resistant and -susceptible Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae. J Antimicrob Chemother. 2004;53(5):793-6.
Walsh, F., Carnegy, F., Willcock, J., & Amyes, S. (2004). Comparative in vitro activity of telithromycin against macrolide-resistant and -susceptible Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae. The Journal of Antimicrobial Chemotherapy, 53(5), 793-6.
Walsh F, et al. Comparative in Vitro Activity of Telithromycin Against Macrolide-resistant and -susceptible Streptococcus Pneumoniae, Moraxella Catarrhalis and Haemophilus Influenzae. J Antimicrob Chemother. 2004;53(5):793-6. PubMed PMID: 15056640.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Comparative in vitro activity of telithromycin against macrolide-resistant and -susceptible Streptococcus pneumoniae, Moraxella catarrhalis and Haemophilus influenzae. AU - Walsh,Fiona, AU - Carnegy,Francis, AU - Willcock,Joanne, AU - Amyes,Sebastian, Y1 - 2004/03/31/ PY - 2004/4/2/pubmed PY - 2004/7/14/medline PY - 2004/4/2/entrez SP - 793 EP - 6 JF - The Journal of antimicrobial chemotherapy JO - J Antimicrob Chemother VL - 53 IS - 5 N2 - OBJECTIVES: The first objective was to investigate the in vitro activity of telithromycin against respiratory tract pathogens in comparison with other antimicrobial agents. The second objective was to identify the influence of the erm(B) and mef(A) genes on the susceptibility of Streptococcus pneumoniae to telithromycin. METHODS: The in vitro activity of telithromycin against S. pneumoniae, Moraxella catarrhalis and Haemophilus influenzae, isolated from the UK and 40 macrolide-resistant S. pneumoniae from four different countries was compared with a variety of antimicrobial agents. The 140 isolates were examined for the presence of the erm(B) and mef(A) genes. The impact of 5% CO(2) on susceptibility testing was also investigated. RESULTS: Telithromycin showed greatest activity against S. pneumoniae, but also had good activity against M. catarrhalis and H. influenzae, which was independent of their resistance profiles to other antibiotics. The MIC(90) of telithromycin for S. pneumoniae was 0.12 mg/L, which was 64-fold lower than the lowest macrolide MIC; 21% of the S. pneumoniae were macrolide resistant. Thirty-eight per cent of the macrolide-resistant strains were erm(B)-positive and 62% were mef(A)-positive, but no strain contained both genes. The activity of telithromycin was similar to that of azithromycin against both M. catarrhalis and H. influenzae, Erythromycin was slightly less active: 1% and 8% of M. catarrhalis and H. influenzae, respectively, were resistant to erythromycin, but none were resistant to telithromycin. Five per cent of the S. pneumoniae strains and 4% of the H. influenzae strains changed from telithromycin susceptible to non-susceptible entirely because of the incubation conditions. The MIC(50)s and MIC(90)s of S. pneumoniae, M. catarrhalis and H. influenzae increased by one dilution when incubated in CO(2). CONCLUSIONS: Telithromycin has shown high in vitro activity against S. pneumoniae, including those strains that are macrolide susceptible and resistant as well as M. catarrhalis and H. influenzae. This study has also demonstrated that there is no cross-resistance between erythromycin and telithromycin. The impact of 5% CO(2) on susceptibility testing should be investigated further before providing definite guidelines on telithromycin susceptibility testing. SN - 0305-7453 UR - https://www.unboundmedicine.com/medline/citation/15056640/Comparative_in_vitro_activity_of_telithromycin_against_macrolide_resistant_and__susceptible_Streptococcus_pneumoniae_Moraxella_catarrhalis_and_Haemophilus_influenzae_ L2 - https://academic.oup.com/jac/article-lookup/doi/10.1093/jac/dkh178 DB - PRIME DP - Unbound Medicine ER -