Effects of clarithromycin at sub-minimum inhibitory concentrations on early ermB gene expression, metabolic activity and growth of an erm(B)-expressing macrolide-resistant strain of Streptococcus pneumoniae

dc.contributor.authorCockeran, Riana
dc.contributor.authorSteel, Helen Carolyn
dc.contributor.authorWolter, Nicole
dc.contributor.authorDe Gouveia, L.
dc.contributor.authorVon Gottberg, Anne
dc.contributor.authorKlugman, Keith P.
dc.contributor.authorLeanord, A.T.
dc.contributor.authorInverarity, D.J.
dc.contributor.authorMitchell, Timothy J.
dc.contributor.authorFeldman, Charles
dc.contributor.authorAnderson, Ronald
dc.contributor.emailriana.cockeran@up.ac.zaen_US
dc.date.accessioned2012-06-19T07:14:09Z
dc.date.available2012-06-19T07:14:09Z
dc.date.issued2012-02
dc.description.abstractAIM: To investigate the effects of exposure of a macrolide-resistant [erm(B)-expressing] strain of Streptococcus pneumo- niae (strain 2507) to clarithromycin (0.5 and 5 mg/L) added at the outset and 6 hours after initiation of culture on early gene expression, energy metabolism, and growth. METHODS: Bacterial growth was determined by turbidometric and colony counting procedures, energy metabolism by measurement of ATP, while analysis of gene expression was per- formed using reverse transcription-PCR and sequencing. RESULTS: Addition of clarithromycin, at either concentration, at the outset of culture, caused transient suppression of growth of 10 - 12 hours duration, while delayed addition of antibi-otic (during the logarithmic phase) resulted in an abrupt halt in growth followed by recovery. These inhibitory effects of clarithromycin on bacterial growth were associated with up-regulation of expression of erm(B), decreased ATP and protein synthesis, and were unaffected by inclusion of either catalase (500 and 1000 kunits/L), or compe- tence-stimulating peptide (CSP-1, 0.5 mg/L). The inhibitory effects could, however, be overcome by pre-exposure of the bacteria to the antibiotic. Moreover, clarithromycin appeared to potentiate the antimicrobial actions of ceftriaxone, at sub-MIC concentrations, for strain 2507. CONCLUSIONS: Unlike several other common bacterial pathogens, the full expression of erm(B)-mediated macrolide resistance by the pneumococcus has a slow onset, which is associated with transient susceptibility to macrolides and inhibition of growth.en_US
dc.description.sponsorshipCF is supported by the National Research Foundation of South Africa.en_US
dc.description.urihttp://www.SciRP.org/journal/ojrden_US
dc.identifier.citationCockeran, R, Steel, HC, Wolter, N, De Gouveia, L, Von Gottberg, A, Klugman, KP, Leanord, AT, Inverarity, DJ, Mitchell, TJ, Feldman, C & Anderson, R 2012, 'Effects of clarithromycin at sub-minimum inhibitory concentrations on early ermB gene expression, metabolic activity and growth of an erm(B)-expressing macrolide-resistant strain of Streptococcus pneumoniae', Open Journal of Respiratory Diseases, vol. 2, no. 1, pp. 1-8.en_US
dc.identifier.issn2163-940X (print)
dc.identifier.issn2163-9418 (online)
dc.identifier.other10.4236/ojrd.2012.21001
dc.identifier.urihttp://hdl.handle.net/2263/19209
dc.language.isoenen_US
dc.publisherScientific Research Publishing Incen_US
dc.rightsCopyright © 2012 SciRes.en_US
dc.subjectClarithromycinen_US
dc.subjectPneumococcusen_US
dc.subjectMacrolide-resistanceen_US
dc.subject.lcshPneumonia -- Treatmenten
dc.titleEffects of clarithromycin at sub-minimum inhibitory concentrations on early ermB gene expression, metabolic activity and growth of an erm(B)-expressing macrolide-resistant strain of Streptococcus pneumoniaeen_US
dc.typeArticleen_US

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