Active substances: Doxycycline
Single-dose azithromycin has been shown in observational studies and 2 randomized clinical trials to be more effective than 7 days of doxycycline for the treatment of M. Failure of azithromycin is predominantly attributable to macrolide resistance mutations in the 23 S ribosomal RNA rRNA molecule within the 50 S subunit of the bacterial ribosome.
These single-nucleotide polymorphisms in position 2058 and 2059 Escherichia coli numbering of the 23 S rRNA gene confer high-level resistance to azithromycin. Selection of resistance following 1 g azithromycin has been described in a number of studies, and an extended azithromycin regimen 500 mg followed by 250 mg daily for 4 days is currently recommended in the European M.
Although there have not been randomized clinical trials comparing 1 g of azithromycin to extended regimens, a number of observational studies and 1 treatment trial included patients treated with both regimens.
Pooled data from these studies 469 M. However, a significant proportion of patients treated with extended azithromycin in these studies had received and failed doxycycline, impacting on the direct comparison of the 2 azithromycin regimens.
Interestingly, several studies have shown that susceptible infections with high bacterial load are more likely to fail and develop detectable posttreatment resistance, supporting the concept of selection and survival of strains with heterotypic resistance; however, work in this area is ongoing.
Mycoplasma genitalium has reduced susceptibility to the fluoroquinolones—levofloxacin and ofloxacin—and greater susceptibility to fourth-generation agents such as moxifloxacin and sitafloxacin.
Moxifloxacin has been the most commonly used fluoroquinolone for macrolide-resistant M. These parC mutations and associated failure of moxifloxacin, although rare in Scandinavia J.
Preliminary studies have shown some evidence of a synergistic effect between moxifloxacin and doxycycline in moxifloxacin-susceptible strains J.
Sitafloxacin, another fourth-generation fluoroquinolone, has in vitro activity against M.
Interestingly, in vitro studies of sitafloxacin show it maintained activity with MICs of 0. Sitafloxacin has lower MICs in moxifloxacin-susceptible isolates and has shown some evidence of susceptibility in isolates that display moxifloxacin resistance J.
Watkins reports that he has received research bacterial sexually transmitted infection worldwide. N Engl J Med.