Mycoplasma genitalium testing pattern and macrolide resistance: a Danish nationwide retrospective survey

Abstract

Background: Mycoplasma genitalium is a common cause of nongonococcal urethritis (NGU) and cervicitis. The aim of the study was to analyze the M. genitalium testing pattern and distribution of positive results according to sex and age in a 5-year period where all diagnostic M. genitalium testing in Denmark was centralized at the Statens Serum Institut. A secondary aim was to estimate the occurrence of macrolide resistance in a 3-year period.

Methods: The study was performed as a nationwide retrospective survey of specimens submitted from general practice, private specialists, and hospitals to Statens Serum Institut for detection of M. genitalium by polymerase chain reaction between 1 January 2006 and 31 December 2010. Macrolide resistance screening was introduced December 2007.

Results: A total of 31 600 specimens from 28 958 patients were tested for M. genitalium, with an increasing trend from 3858 per year in 2006 to 7361 in 2010. The majority (54%) of the patients were tested in general practice. For both sexes, the positive rate increased significantly, from 2.4% to 3.8% for women and from 7.9% to 10.3% for men (P < .0005). Macrolide resistance was detected in 38% (385/1008) of the M. genitalium-positive patients, and the highest rate was found in patients tested at sexually transmitted disease clinics (43%).

Conclusions: Testing for M. genitalium has become important for clinicians treating sexually transmitted infections. In this nationwide survey, macrolide resistance was found in almost 40% of the specimens, raising concern about single-dose azithromycin treatment of NGU, and emphasizing that NGU treatment should be guided by etiologic diagnosis.

Keywords: Mycoplasma genitalium; macrolide resistance; prevalence.

Figure 1.

Number of patients tested for Mycoplasma genitalium per calendar year in Denmark, 1 January 2006–31 December 2010, stratified by sex: women (black) and men (gray). The lines indicate the positivity rate for women (dotted black line) and men (solid black line).

Figure 2.

Age distribution of Danish men tested for Mycoplasma genitalium. White bars: total number of men tested; black bars: number of men testing positive. The age-specific positivity rate among Danish men is indicated by the dotted line.

Figure 3.

Age distribution of Danish women tested for Mycoplasma genitalium. White bars: total number of women tested; black bars: number of women testing positive. The age-specific positivity rate among Danish women is indicated by the dotted line.

Figure 4.

Distribution of macrolide resistance–mediating mutations in region V of the 23S ribosomal RNA gene.