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.
Department of Otolaryngology, Wakayama Medical University, Japan.
Dewan Sakhawat
DS
Billal
Muneki
M
Hotomi
Steve S
SS
Yan
Daniel P
DP
Fedorko
Jun
J
Shimada
Keiji
K
Fujihara
Noboru
N
Yamanaka
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