(Small, Sneaky & Sinister) 

In the past few years there’s been a rise in questioning the impact of Mycoplasma and Ureaplasma bacteria on the vaginal microbiome. These lesser known pathogens are slowly starting to become better understood. 

 

1. What are Mycoplasma and Ureaplasma?

Mycoplasma and Ureaplasma are very small and unusual bacteria. They lack a typical bacterial cell wall, which allows them to resist certain antibiotics. Due to their size and relative antibiotic resistance, these bacteria often go overlooked, undiagnosed, and undetected. This can be particularly troublesome if they inhabit your respiratory or urogenital tract. 

 

The most problematic Mycoplasma and Ureaplasma species for vaginal health (1)  

  • Mycoplasma hominis is found in the vagina and cervix in 20-50% of sexually mature women. 
  • Ureaplasma urealyticum and U. parvum are present in vagina of 40-80% of women.  
  • Mycoplasma genitaliuim is present in vagina of up to 5% of women.  

Given their high prevalence, it's evident that the presence of these organisms doesn't necessarily indicate an infection or complication. However, scientific understanding has advanced significantly. Nearly 30 years ago, Ureaplasma urealyticum wasn't taken seriously, and limited reports led scientists to conclude that its presence in the lower genital tract wasn't associated with premature birth (2).  

 

 2. What issues can Mycoplasma and Ureaplasma cause? 

The recent studies and systematic reviews demonstrate that Mycoplasma and Ureaplasma have been associated with some serious urogenital conditions.  

  • Mycoplasma hominis: urethritis, bacterial vaginosis (3), cervicitis, pelvic inflammatory syndrome, infertility in both men and women (4), early miscarriages and mid-trimester miscarriage (5)  
  • Mycoplasma genitalium: cervicitis, preterm birth and miscarriages (6) 
  • Ureaplasma spp: infertility, increased risk for spontaneous preterm birth, premature rupture of foetal membranes, miscarriage, stillbirth, babies with low birth weight, bronchopulmonary disease in the preterm babies (7,8) 

Despite acknowledging the risks, the official clinical practice still does not include   screening for Mycoplasma and Ureaplasma in asymptomatic pregnancy (6,9).    

 

3. What are some of the common symptoms of Mycoplasma and Ureaplasma infection? 

The most common symptoms of Mycoplasma and Ureaplasma infections are: 

  • vaginal burning  
  • abnormal thick discharge (can be mistaken for thrush) 
  • dysuria – pain during urination 
  • recurrent infections (return of an infection after effective treatment) 
  • intermenstrual spotting 
  • cervicitis 
  • pelvic inflammatory disease 
  • high inflammation (not always present) 

There was interesting research conducted on 89 women at a sexually transmitted disease clinic. 38 women had high risk vaginal pH of 5-5.5, of which 55% had normal vaginal discharge. 51 had high risk vaginal pH of 6-7.5, of which only 14% had normal vaginal discharge. The interesting find was that the high pH group had also 2-3x higher levels of Mycoplasma hominis. The results indicate that a pH of ≥ 6.0 is strongly predictive of an infection and may be more useful than the type of discharge (10).  

If you experience any of these symptoms, consult your healthcare professional. As these symptoms are not specific to these bacterial organisms, specific diagnostic tests are required for an accurate diagnosis. Vaginal microbiome testing is performed using a vaginal swab sample, as urine samples have proven unreliable. Conventional diagnostic methods include culture methods and PCR tests. In a study involving 228 Korean pregnant women, these diagnostic tests were compared with vaginal microbial community analysis. The study confirmed that PCR testing is more accurate than culture methods (11).  

A complete vaginal microbiome mapping is more appropriate for identifying other  organisms in the vagina and depicting their proportionate quantity in the  overall microbiome.

As mentioned before, these organisms have a high prevalence in the vagina and their presence can be completely asymptomatic. It is also important to note that Mycoplasma and Ureaplasma can be transmitted through sexual contact and men can be asymptomatic carriers.  

 

4. How to treat Mycoplasma and Ureaplasma infection? 

If you are symptomatic, consult your healthcare professional. They will conduct the necessary diagnostic tests to determine the cause of your symptoms. If you test positive for Mycoplasma and Ureaplasma they will prescribe an appropriate antibiotic treatment. It is crucial to use antibiotics that do not target peptidoglycans on the cell wall (as Mycoplasma and Ureaplasma do not have one). The currently used antibiotics and their effectiveness against Mycoplasma and Ureaplasma species are listed below (12).  

  • Mycoplasma hominis treatment: clindamycin, fluoroquinolones (levofloxacin, moxifloxacin) 
    • Resistant to tetracycline (20-40% isolates), clarithromycin, erythromycin, azithromycin 
  • Ureaplasma spp. treatment: erythromycin, azithromycin (single 1g dose), fluoroquinolones 
    • clarithromycin effective in lab experiments, but not approved for use in the treatment of urogenital infections in USA 
    • Resistant to tetracycline (45% isolates) 
    • U. parvum is susceptible to doxycycline (resistance in 0.5% isolates)  

It is important to treat both yourself and your sexual partner simultaneously while avoiding all forms of sexual activity while on antibiotics (and this includes vaginal, oral, anal sex, use of sex toys, with or without condoms) (13). 

Figure 1. Statistically significant difference in relative abundance of Ureaplasma parvum (%) between control and probiotic group after 4 weeks. Adapted from Schenk et al., 2021. 

It is also important to support your vaginal microbiome with healthy, vaginally active probiotics. In a randomised prospective clinical trial involving 80 Austrian women with primary or secondary infertility and no vaginal infections, participants took oral probiotics for 4 weeks. Although the study showed no significant shift in the vaginal microbiome community, the probiotic group experienced significantly limited growth of Ureaplasma parvum compared with the control group that did not take probiotics (see Figure 1) (14).  

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References

See list of references used on this page

  1. Taylor-Robinson D. Mollicutes in vaginal microbiology: Mycoplasma hominis, Ureaplasma urealyticum, Ureaplasma parvum and Mycoplasma genitalium. Res Microbiol. 2017 Nov-Dec;168(9-10):875-881. doi: 10.1016/j.resmic.2017.02.009. 
  2. Eschenbach DA. Ureaplasma urealyticum and premature birth. Clin Infect Dis. 1993 Aug;17 Suppl 1:S100-6. doi: 10.1093/clinids/17.supplement_1.s100. 
  3. Foxman, B., Wen, A., Srinivasan, U., Goldberg, D., Marrs, C. F., Owen, J., Wing, D. A. & Misra, D. (2014). Mycoplasma, bacterial vaginosis associated bacteria BVAB3, race, and risk of preterm birth in a high risk cohort. Am J Obstet Gynecol 210, e1–e7. 
  4. Ahmed J, Rawre J, Dhawan N, Khanna N, Dhawan B. Mycoplasma hominis: An under recognized pathogen. Indian J Med Microbiol. 2021 Jan;39(1):88-97. doi: 10.1016/j.ijmmb.2020.10.020. 
  5. Noda-Nicolau NM, Tantengco OAG, Polettini J, Silva MC, Bento GFC, Cursino GC, Marconi C, Lamont RF, Taylor BD, Silva MG, Jupiter D, Menon R. Genital Mycoplasmas and Biomarkers of Inflammation and Their Association With Spontaneous Preterm Birth and Preterm Prelabor Rupture of Membranes: A Systematic Review and Meta-Analysis. Front Microbiol. 2022 Mar 30;13:859732. doi: 10.3389/fmicb.2022.859732.  
  6. Donders GGG, Ruban K, Bellen G, Petricevic L. Mycoplasma/Ureaplasma infection in pregnancy: to screen or not to screen. J Perinat Med. 2017 Jul 26;45(5):505-515. doi: 10.1515/jpm-2016-0111.  
  7. Ljubin-Sternak S, Meštrović T. Chlamydia trachomatis and Genital Mycoplasmas: Pathogens with an Impact on Human Reproductive Health. J Pathog. 2014;2014:183167. doi: 10.1155/2014/183167.  
  8. Viscardi RM. Ureaplasma species: role in neonatal morbidities and outcomes. Arch Dis Child Fetal Neonatal Ed. 2014 Jan;99(1):F87-92. doi: 10.1136/archdischild-2012-303351. 
  9. Frenzer C, Egli-Gany D, Vallely LM, Vallely AJ, Low N. Adverse pregnancy and perinatal outcomes associated with Mycoplasma genitalium: systematic review and meta-analysis. Sex Transm Infect. 2022 May;98(3):222-227. doi: 10.1136/sextrans-2021-055352.  
  10. Hanna NF, Taylor-Robinson D, Kalodiki-Karamanoli M, Harris JR, McFadyen IR. The relation between vaginal pH and the microbiological status in vaginitis. Br J Obstet Gynaecol. 1985 Dec;92(12):1267-71. doi: 10.1111/j.1471-0528.1985.tb04874.x.  
  11. Oh KY, Lee S, Park J, Park MH, Jeong JH, Yang JB, Lim CK, Ha JG, Yang YS. Vaginal microbiota of pregnant women with Ureaplasma urealyticum and Mycoplasma hominis infections. Front Cell Infect Microbiol. 2024 Sep 9;14:1445300. doi: 10.3389/fcimb.2024.1445300. 
  12. Waites KB. Ureaplasma Infection Medication, Medscape, November 2022.  
  13. University of Wisconsin School of Medicine and Public Health, Ureaplasma urealyticum and Mycoplasma Hominis, Treatment. December 2022. 
  14. Schenk M, Grumet L, Sternat J, Reinschissler N, Weiss G. Effect of probiotics on vaginal Ureaplasma parvum in women suffering from unexplained infertility. Reprod Biomed Online. 2021 Sep;43(3):503-514. doi: 10.1016/j.rbmo.2021.06.004.