Alterations in regulatory regions of erm(B) genes from clinical isolates of enterococci resistant to telithromycin

Abstract

We determined rates of resistance to the ketolide telithromycin in 56 Enterococcus faecalis isolates and 44 Enterococcus faecium isolates collected from hospitals in Korea between 2005 and 2006. Twenty nine (51.8%) isolates of E. faecalis and 35 (79.5%) isolates of E. faecium were resistant to telithromycin (minimum inhibitory concentrations, ≥ 4 μg/mL). All of the telithromycin-resistant E. faecalis carried the erm(B) gene only. Of the telithromycin-resistant E. faecium, 29 resistant strains carried erm(B) only, the other six carried erm(A) and erm(B) together. The nucleotide sequence of the erm(B) regulatory regions from 29 E. faecalis and 29 E. faecium isolates with erm(B) only was analyzed. Five types of alterations were detected. The first and second types had point mutations that destabilize the secondary structure of erm(B) mRNA sequestering the translation initiation region of the structural gene. The third type was identical to erm(Bv1), a previously reported variant of erm(B) with different induction specificity. The fourth and fifth types had point mutations within the critical sequence for induction and a point mutation destabilizing the stem-loop of erm(B) mRNA sequestering the translation initiation region of the structural gene.

High prevalence of vancomycin and high-level gentamicin resistance in Enterococcus faecalis isolates

“…The various distributions of erm genes were shown in previous studies [5,14,15,50,51]. However, ermB gene is the most prevalent one among enterococcal species and ermA gene is more commonly found in staphylococcal strains [15,[51][52][53][54][55][56].…”

The Expression of Antibiotic Resistance Methyltransferase Correlates with mRNA Stability Independently of Ribosome Stalling

“…S2A in the supplemental material). None of these alanine substitutions has been reported in the natural isolates; however, nonsense mutations, insertions, and deletions of ErmBL have been frequently found in clinical strains that exhibit high levels of multidrug resistance (34, 35, 37, 39, 40, 43, 60). Constitutive resistance derived from a complete loss of the ermBL regulatory region has been interpreted as a permanent disruption of the inhibitory mRNA structure that leads to downstream ErmB activation.…”

Ανάπτυξη Και Χαρακτηρισμός Νέων Αντιβιοτικών - Αναστολέων Της Πρωτεϊνικής Σύνθεσης

“…Οη πην ζπλήζεο κεραληζκνί αλζεθηηθφηεηαο πνπ αλαπηχζζνπλ ηα καθξνιίδηα αθνξνχλ ηελ απέθθξηζε απφ ην θχηηαξν θαη ηελ ηξνπνπνίεζε ηνπ ζηφρνπ ηνπ αληηβηνηηθνχ ζηελ πεξηνρή ηνπ ηνχλει εμφδνπ ηεο πνιππεπηηδηθήο αιπζίδαο (Lovmar et al, 2009;Vester and Douthwaite, 2001;Douthwaite, 2010 (Min et al, 2011;Douthwaite et al, 2000;Bogdanovich et al, 2006). Έρνπλ δηαπηζησζεί θαηλφκελα αλζεθηηθφηεηαο εμαηηίαο κεηαιιάμεσλ ζηελ ξηβνζσκαηή πξνηετλε L4, θαζψο πξνθαινχλ κία ζηέλσζε ζην ηνχλει εμφδνπ, ελψ αληίζεηα κεηαιιάμεηο ζηελ L22 δελ θαίλεηαη λα επεξεάδνπλ άκεζα ηε ρεκηθή ζπγγέλεηα ηνπ θαξκάθνπ, άιια κάιινλ δξνπλ έκκεζα (Moore and Sauer, 2008;Diner and Hayes, 2009).…”