Loss of erythromycin resistance genes from strains of Streptococcus pyogenes that have developed resistance to levofloxacin.
In the past 2 to 3 decades, erythromycin resistance in Streptococcus pyogenes has been decreasing, whereas fluoroquinolone resistance (or reduction in its susceptibility) has been reported often. Although a shift of M-type prevalence and decreased pressure from macrolides have been suggested for the decrease in erythromycin resistance, we hypothesized that this might also be a result of increased antimicrobial pressure from fluoroquinolone use. Levofloxacin resistance for 4 erythromycin-resistant parent strains was induced in vitro. Their mutants became highly resistant to the fluoroquinolones but lost their erythromycin resistance trait. Erythromycin resistance was fully restored by transconjugation with respective parent strains with either mefA- or ermTR-mediated mechanisms.
Billal
Dewan Sakhawat
DS
Department of Otolaryngology, Wakayama Medical University, Japan.
Hotomi
Muneki
M
Yan
Steve S
SS
Fedorko
Daniel P
DP
Shimada
Jun
J
Fujihara
Keiji
K
Yamanaka
Noboru
N
D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003227:Conjugation, Genetic; D024881:Drug Resistance, Bacterial; D004917:Erythromycin / Q000494:pharmacology*; D017353:Gene Deletion; D022761:Gene Transfer, Horizontal; D005798:Genes, Bacterial; D005838:Genotype; D006801:Humans; D064704:Levofloxacin; D008826:Microbial Sensitivity Tests; D015242:Ofloxacin / Q000494:pharmacology*; D013297:Streptococcus pyogenes / Q000187:drug effects / Q000235:genetics*
D000900:Anti-Bacterial Agents; D004917:Erythromycin; D064704:Levofloxacin; D015242:Ofloxacin