<i>Streptococcus pyogenes</i>
            Isolates with High-Level Macrolide Resistance and Reduced Susceptibility to Telithromycin Associated with 23S rRNA Mutations

Farrell, David J.; Shackcloth, Jemma; Barbadora, Karen A.; Green, Michael D.

doi:10.1128/aac.50.2.817-818.2006

Cited by 15 publications

(8 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…MLS B -ketolide resistance in Streptococcus pyogenes is mediated by either active efflux of the drug, inhibition of protein synthesis by methylation [mediated by either erm(B) or erm(A) subclass erm(TR)] or mutation at critical binding domains of the 23S rRNA target [33]. To date, telithromycin resistance in S. pyogenes has been mediated by either mutations in the erm(B) gene that result in a reduced inhibitory effect on both translation and 50S subunit synthesis [34] or by ribosomal mutations in the 23S rRNA alleles [35]. It will be interesting to investigate the mechanism responsible for telithromycin resistance in the 44 strains in this study as this information may provide clues to the ribosomal binding sites of CEM-101 that sustain activity.…”

Section: Resultsmentioning

confidence: 99%

Antimicrobial characterisation of CEM-101 activity against respiratory tract pathogens, including multidrug-resistant pneumococcal serogroup 19A isolates

Farrell¹,

Sader²,

Castanheira³

et al. 2010

International Journal of Antimicrobial Agents

Self Cite

View full text Add to dashboard Cite

Section: Resultsmentioning

confidence: 99%

Antimicrobial characterisation of CEM-101 activity against respiratory tract pathogens, including multidrug-resistant pneumococcal serogroup 19A isolates

Farrell¹,

Sader²,

Castanheira³

et al. 2010

International Journal of Antimicrobial Agents

Self Cite

View full text Add to dashboard Cite

“…A possible explanation for the presence of erythromycin resistance besides mef A, erm B, and erm TR genes includes mutations of the 23S rRNA and the L4 ribosomal protein (not investigated). 25,26 …”

Section: Discussionmentioning

confidence: 99%

Phenotypes and genotypes of erythromycin-resistant Streptococcus pyogenes strains isolated from invasive and non-invasive infections from Mexico and the USA during 1999–2010

Villaseñor-Sierra

Katahira²,

Jaramillo-Valdivia

et al. 2012

International Journal of Infectious Diseases

View full text Add to dashboard Cite

Summary Objective To compare the prevalence, phenotypes, and genes responsible for erythromycin resistance among Streptococcus pyogenes isolates from Mexico and the USA. Methods Eighty-nine invasive and 378 non-invasive isolates from Mexico, plus 148 invasive, 21 non-invasive, and five unclassified isolates from the USA were studied. Susceptibilities to penicillin, erythromycin, clindamycin, ceftriaxone, and vancomycin were evaluated according to Clinical and Laboratory Standards Institute (CLSI) standards. Phenotypes of erythromycin resistance were identified by triple disk test, and screening for mefA, ermTR, and ermB genes was carried out by PCR. Results All isolates were susceptible to penicillin, ceftriaxone, and vancomycin. Erythromycin resistance was found in 4.9% of Mexican strains and 5.2% of USA strains. Phenotypes in Mexican strains were 95% M and 5% cMLS; in strains from the USA, phenotypes were 33.3% iMLS, 33.3% iMLS-D, and 33.3% M. Erythromycin resistance genes in strains from Mexico were mefA (95%) and ermB (5%); USA strains harbored ermTR (56%), mefA (33%), and none (11%). In Mexico, all erythromycin-resistant strains were non-invasive, whereas 89% of strains from the USA were invasive. Conclusions Erythromycin resistance continues to exist at low levels in both Mexico and the USA, although the genetic mechanisms responsible differ between the two nations. These genetic differences may be related to the invasive character of the S. pyogenes isolated.

show abstract

“…Here, the presence of 23S rRNA methylases (ermA, ermB, ermC, and ermF genes), a plasmid-mediated efflux pump (mefA/E genes), macrolide 2Ј-phosphotransferase (mphA gene), ERY esterases (ereA and ereB genes), and possible mutations in the mtrR gene/promoter and riboproteins L4 and L22 (rplD and rplV genes) were tested in all the isolates with ERY rs . Moreover, mutations in the 4 copies of the 23S rRNA genes identified in N. gonorrhoeae were analyzed, as well, using the strategy described by Farrell and colleagues (16,17). Briefly, a common primer inside the 4 copies of the 23S rRNA genes and specific external primers close to each of them were designed from the complete N. gonorrhoeae NCCP11945 genome (accession number NC_011035).…”

Section: Resultsmentioning

confidence: 99%

Molecular Analysis of Antimicrobial Resistance Mechanisms in Neisseria gonorrhoeae Isolates from Ontario, Canada

Allen

Farrell

Rebbapragada

et al. 2011

Antimicrob Agents Chemother

Self Cite

View full text Add to dashboard Cite

Surveillance of gonococcal antimicrobial resistance and the molecular characterization of the mechanisms underlying these resistance phenotypes are essential in order to establish correct empirical therapies, as well as to describe the emergence of new mechanisms in local bacterial populations. To address these goals, 149 isolates were collected over a 1-month period (October-November 2008) at the Ontario Public Health Laboratory, Toronto, Canada, and susceptibility profiles (8 antibiotics) were examined. Mutations in previously identified targets or the presence of some enzymes related to resistance (r), nonsusceptibility (ns) (resistant plus intermediate categories), or reduced susceptibility (rs) to the antibiotics tested were also studied. A significant proportion of nonsusceptibility to penicillin (PEN) (89.2%), tetracycline (TET) (72.3%), ciprofloxacin (CIP) (29%), and macrolides (erythromycin [ERY] and azithromycin; 22.3%) was found in these strains. Multidrug resistance was observed in 18.8% of the collection. Although all the strains were susceptible to spectinomycin and extended-spectrum cephalosporins (ESC) (ceftriaxone and cefixime), 9.4% of them displayed reduced susceptibility to extended-spectrum cephalosporins. PBP 2 mosaic structures were found in all of these ESC rs isolates. Alterations in the mtrR promoter, MtrR repressor (TET r , PEN ns , ESC rs , and ERY ns ), porin PIB (TET r and PEN ns ), and ribosomal protein S10 (TET r ) and double mutations in gyrA and parC quinolone resistance-determining regions (QRDRs) (CIP r ) were associated with and presumably responsible for the resistance phenotypes observed. This is the first description of ESC rs in Canada. The detection of this phenotype indicates a change in the epidemiology of this resistance and highlights the importance of continued surveillance to preserve the last antimicrobial options available.

show abstract

Streptococcus pyogenes Isolates with High-Level Macrolide Resistance and Reduced Susceptibility to Telithromycin Associated with 23S rRNA Mutations

Cited by 15 publications

References 9 publications

Antimicrobial characterisation of CEM-101 activity against respiratory tract pathogens, including multidrug-resistant pneumococcal serogroup 19A isolates

Antimicrobial characterisation of CEM-101 activity against respiratory tract pathogens, including multidrug-resistant pneumococcal serogroup 19A isolates

Phenotypes and genotypes of erythromycin-resistant Streptococcus pyogenes strains isolated from invasive and non-invasive infections from Mexico and the USA during 1999–2010

Molecular Analysis of Antimicrobial Resistance Mechanisms in Neisseria gonorrhoeae Isolates from Ontario, Canada

Contact Info

Product

Resources

About