Use of Pristinamycin for Macrolide-Resistant Mycoplasma genitalium Infection

Abstract

High levels of macrolide resistance and increasing fluoroquinolone resistance are found in Mycoplasma genitalium in many countries. We evaluated pristinamycin for macrolide-resistant M. genitalium in a sexual health center in Australia. Microbiologic cure was determined by M. genitalium-specific 16S PCR 14-90 days after treatment began. Of 114 persons treated with pristinamycin, infection was cured in 85 (75%). This percentage did not change when pristinamycin was given at daily doses of 2 g or 4 g or at 3 g combined with 200 mg doxycycline. In infections with higher pretreatment bacterial load, treatment was twice as likely to fail for each 1 log₁₀ increase in bacterial load. Gastrointestinal side effects occurred in 7% of patients. Pristinamycin at maximum oral dose, or combined with doxycycline, cured 75% of macrolide-resistant M. genitalium infections. Pristinamycin is well-tolerated and remains an option where fluoroquinolones have failed or cannot be used.

Keywords: Australia; Mycoplasma genitalium; antimicrobal resistance; bacteria; nongonococcal urethritis; pelvic inflammatory disease; pristinamycin; sexually transmitted infections.

Figure 1

Selection of cases for analysis of microbiological cure of Mycoplasma genitalium infections with pristinamycin, Melbourne Sexual Health Centre, Melbourne, Victoria, Australia, 2012–2016.

Figure 2

Mycoplasma genitalium bacterial loads (log₁₀) and treatment outcomes, Melbourne Sexual Health Centre, Melbourne, Victoria, Australia, 2012–2016. A) M. genitalium load compared in urine (n = 67), rectal swab (n = 26), and cervical swab (n = 3) samples. For urine vs. rectal samples, p = 0.56; for urine vs. cervical samples, p = 0.70. B) Comparison of pretreatment M. genitalium loads in infections not cured (n = 26) and cured (n = 71) by pristinamycin. p<0.01. C) Comparison of M. genitalium loads in pretreatment and posttreatment samples from cases in which pristinamycin failed (n = 26). p<0.001..Box plots indicate 25th percentile (bottom of box), 75th percentile (top of box), median (horizontal line within box), and range (whiskers). Dots represent outlying individual observations.Dots under the error bars indicate individual outliers.