Abstract
Three-site genital and extragenital screening for Mycoplasma genitalium in 102 asymptomatic Air Force members with human immunodeficiency virus (HIV) infection revealed 19 (18.6%) cases of M. genitalium, commonly (58%) in rectal samples. Because M. genitalium is associated with both HIV acquisition and transmission, these findings suggest that it should be included in routine screening of HIV-infected individuals for sexually transmitted infections.
Keywords: Mycoplasma genitalium HIV Air Force
The rates of curable sexually transmitted infections (STIs)— chlamydia, gonorrhea, and syphilis—have been rising in the United States, especially among individuals aged 15–24 years and men who have sex with men (MSM), with highest reported rates in the southern and northeastern United States [1]. Among MSM, the prevalence of STIs was higher among men with human immunodeficiency virus (HIV) infection than among those who were uninfected [1]. STIs are risk factors for HIV acquisition and transmission. Neisseria gonorrhoeae infection, Trichomonas vaginalis infection, urethritis, and other STIs have been associated with increased HIV viral load levels in semen, thereby increasing its infectious potential and HIV disease progression [2, 3]. National STI treatment guidelines recommend screening for Chlamydia trachomatis, N. gonorrhoeae, and syphilis at the first HIV-related visit and at subsequent annual visits [4].
Mycoplasma genitalium has been recognized as an etiologic agent of urethritis in men, and data suggest an association with symptomatic proctitis, with patients exihibiting symptoms having a 26% higher load of M. genitalium than asymptomatic patients [5]. In an effort to inform and enhance STI screening among HIV-infected US Air Force (USAF) members, screening for M. genitalium and T. vaginalis was added to the existing STI panel among patients with new or chronic HIV infection.
METHODS
Patient Population
By Air Force regulation, active duty personnel with a diagnosis of HIV infection undergo mandatory medical evaluations every 6–12 months at the USAF HIV Medical Evaluation Unit (MEU; Joint Base San Antonio, Texas) [6]. All HIV-infected service members with a clinical visit from May 16 through 30 September 2016 were included in this analysis.
Urine and extragenital samples from patients were tested for M. genitalium and T. vaginalis. A nurse practitioner collected an extra rectal and oropharyngeal sample from all patients routinely tested for extragenital C. trachomatis and N. gonorrhoeae and conducted a brief risk assessment using a standardized 1-page instrument that solicited patient demographics, history of STI diagnosis and symptoms, and sexual contact and condom use since the last visit or in the past year. In addition, an aliquot of urine, provided by patients for urinalysis and C. trachomatis and N. gonorrhoeae testing, was acquired for M. genitalium and T. vaginalis screening. Patient testing and data collection were undertaken as a part of an HIV/blood-borne pathogen threat reduction project that was approved by the Army Public Health Center’s Public Health Research Board (No. 14–311) as a public health programmatic activity, and by the Walter Reed Army Institute of Research’s Institutional Review Board (No. 1861E) as a public health activity/clinical initiative and did not require informed consent.
Laboratory Procedures
All extragenital and urine samples for M. genitalium and T. vaginalis screening were collected in a urine transport tube, or a unisex swab collection kit (Aptima; Hologic) and shipped to the HIV Diagnostics and Reference Laboratory for analysis. Two nucleic acid amplification test assays conducted on the Panther platform (Hologic) were used for qualitative detection of ribosomal M. genitalium and T. vaginalis RNA (Aptima M. genitalium research-use-only analyte-specific reagents and Aptima T. vaginalis, Hologic). Validations of M. genitalium and T. vaginalis assays for extragenital samples were performed at the HIV Diagnostics and Reference Laboratory by calculating the percentage of agreement in a comparison study with reference specimens obtained from College of American Pathology–accredited laboratories performing the same assays on the Panther platform. A specimen was considered positive for M. genitalium if the assay result was ≥50 000 relative light units (RLU) [7, 8]. Testing for C. trachomatis and N. gonorrhoeae were conducted at MEU clinical laboratories at routine visits for HIV care.
Data Analysis
Demographic, laboratory, behavioral risk, and clinical characteristics for the patient population were assessed using data collected from risk assessment interview, local and send-out laboratory results, and past STI history extracted from electronic medical records available for service members since their entry into military service or since 2004 when the electronic medical record system was implemented. The risk assessment form solicited information about patient symptoms such as discharge or discharge or itching or burning in the penis, vagina, or anus; pain during sexual intercourse or in the lower abdominal area or the rectum/during bowel movements; or bleeding from the rectum/anus, or ulcers/sores in the genital area. The overall frequency (prevalence) of M. genitalium, T. vaginalis, C. trachomatis, and N. gonorrhoeae was examined, as well as the frequency of M. genitalium by demographic and clinical characteristics and 2-tailed confidence intervals at 0.95 probability (95% CIs), obtained using the Clopper-Pearson (exact) method. To compare proportions, prevalence odds ratios (ORs) and tests of significance were estimated using logistic regression. Data were managed and analyzed using Statistical Analysis Software (SAS; version 9.3).
RESULTS
Patient Population
A total of 102 patients received HIV care at the MEU from May 16 through 30 September 2016 and provided 298 urine, rectal, or oropharyngeal samples (Table 1). Almost all patients (99%) were male, with a median age of 31.0 years (interquartile range [IQR], 26.0–36.0 years) and an HIV diagnosis for a median of 3 years (IQR, 1–6 years); a majority (74%) had an undetectable or unquantifiable viral load (<20 copies/mL), and the median CD4 cell count was 748.0 cells/µL (IQR, 573.5–976.5 cells/µL).
Table 1.
Prevalence of Mycoplasma genitalium by Patient Characteristics
| Characteristic | Patients Positive for M. genitalium, No./ Patients Tested No. (Prevalence %; 95% CI) | Prevalence OR (95% CI) | P Value |
|---|---|---|---|
| Age, y | |||
| 20–29 | 8/46 (17.4; 7.8–31.4) | 1.00 | … |
| 30–60 | 11/56 (19.6; 10.2–32.4) | 1.16 (.42–3.18) | .77 |
| Race | |||
| White | 10/40 (25.0; 12.7–41.2) | 1.96 (.72–5.37) | .19 |
| Black | 9/50 (18.0; 8.6–31.4) | 1.00 | … |
| Other | 0/12 (0.0; 0.0–26.5) | ||
| Education, highest level | |||
| High school | 2/12 (16.7; 2.1–48.4) | 1.00 | … |
| Some college or more | 17/90 (18.9; 11.4–28.5) | 1.16 (.23–5.81 | .85 |
| Marital status | |||
| Ever married | 5/31 (16.1; 5.5–33.7) | 1.00 | … |
| Never married | 14/71 (19.7; 11.2–30.9) | 1.28 (.42–3.92) | .67 |
| Pay grade | |||
| E1–E5 | 12/62 (19.4; 10.4–31.4) | 1.20 (.35–4.17) | .77 |
| E6–E9 | 4/24 (16.7; 4.7–37.4) | 1.00 | … |
| Officer | 3/16 (18.7; 4.0–45.6) | 1.15 (.22–6.02) | .87 |
| Ethnicity | |||
| Missing | 8/59 (13.5; 6.0–25.0) | … | … |
| Hispanic | 5/13 (38.5; 13.9–68.4) | 2.50 (.60–10.46 | .21 |
| Non-Hispanic | 6/30 (20.0; 7.7–38.6) | 1.00 | … |
| Sample typea | |||
| Urine | 9/97 (9.3; 4.3–16.9) | … | … |
| Rectal swab | 11/99 (11.1; 5.7–19.0) | … | … |
| Pharyngeal swab | 1/102 (0.98; 0.0–5.3) | … | … |
| Coinfection with Chlamydia trachomatis/Neisseria gonorrhoeae | |||
| Yes | 2/15 (13.3; 1.7–40.5) | 1.00 | … |
| No | 16/86 (18.6; 11.0–28.4) | 1.48 (.30–7.24) | .62 |
| Coinfection with C. trachomatis | |||
| Yes | 2/10 (20.0; 1.7–40.5) | 1.09 (.21–5.65) | .91 |
| No | 16/86 (18.6; 10.2–25.8) | 1.00 | … |
| Coinfection with N. gonorrhoeae | |||
| Yes | 0/7 (0.0; 0.0–41.0) | … | |
| No | 17/87 (19.5; 11.8–29.4) | … | |
| History of past STI | |||
| Yes | 12/54 (22.2; 12.0–35.6) | 1.67 (.60–4.67) | .32 |
| No | 7/48 (14.6; 6.1–27.8) | 1.00 | … |
| History by type | |||
| C. trachomatis | 6/24 (25.0; 9.8–46.7) | 1.67 (.56–5.00) | .36 |
| N. gonorrhoeae | 7/27 (25.9; 11.1–46.3) | 1.84 (.64–5.30) | .26 |
| Syphilis | 1/4 (25.0; 0.6–80.6) | 1.48 (.15–15.08) | .74 |
| Other STI | 5/16 (31.2; 11.0–58.7) | 2.34 (.70–7.78) | .17 |
| Treatment history | |||
| Azithromycin (1 g; oral)/ rocephin (250 mg)/ doxycycline (100 mg)/ cefixime (400 mg) | 9/38 (23.7; 11.4–40.2) |
1.68 (.61–4.59) | .31 |
| None | 10/64 (15.6; 7.8–26.9) | 1.00 | … |
| Symptomsb of STI before visit | |||
| Yes | 6/22 (27.3; 10.7–50.2) | 1.93 (.64–5.87) | .24 |
| No | 13/80 (16.3; 8.9–26.2) | 1.00 | … |
| Urine leukocyte esterase | |||
| Positive | 3/7 (42.8; 10.7–26.8) | 3.90 (.79–19.23) | .09 |
| Negative | 15/93 (16.1; 9.7–24.7) | 1.00 | … |
| Time since HIV diagnosis, y | |||
| 0–1 | 11/44 (25.0; 13.2–40.3) | 2.08 (.76–5.73) | .15 |
| 2–16 | 8/58 (13.8; 6.1–25.4) | 1.00 | … |
| Type of sexual partners in past year | |||
| Men, men and women | 18/75 (24.0; 14.9–35.3) | 8.21 (1.04–64.81) | .046 |
| None/women only | 1/27 (3.7; 0.1–19.0) | 1.00 | … |
| New same-sex/male partner in past year | |||
| Yes | 11/41 (26.8; 14.2–42.9) | 2.43 (.88–6.70) | .09 |
| No | 8/61 (13.1; 5.8–24.2) | 1.00 | … |
… denotes that the logistic regression model could not be fit to the data.
Abbreviations: CI, confidence interval; HIV, human immunodeficiency virus; OR, odds ratio; STI, sexually transmitted infection.
aTwo patients had positive results in both urine and rectal samples.
bPatients were asked if they had had discharge or itching or burning in the penis, vagina, or anus; pain during sexual intercourse or in the lower abdominal area or the rectum/during bowel movements; or bleeding from the rectum/anus, or ulcers/sores in the genital area.
Frequency of Sexually Transmitted Infection
Nineteen patients (18.6%; 95% CI, 11.6%–27.6%) tested positive for M. genitalium in 21 specimens (11 of 21 positive specimens [52.3%] were rectal specimens, 9 [42.9%] were urine specimens, and 1 [4.8%] was an oropharyngeal specimen); all 19 patients were male. Two patients (2%; 95% CI, 0.2%–6.9%) tested positive for T. vaginalis, exclusively in oropharyngeal samples. No one was coinfected with M. genitalium and T. vaginalis. The prevalence of other STIs was as follows: C. trachomatis, 9.8% (95% CI, 5.1%–18.3%; 10 of 96); N. gonorrhoeae, 6.9% (3.0%–14.7%; 7 of 94), and C. trachomatis/N. gonorrhoeae, 15% (8.6%–23.3%; 15 of 101); only 2 patients were coinfected with M. genitalium and C. trachomatis, and none with M. genitalium and N. gonorrhoeae.
A higher prevalence of M. genitalium was detected among patients who were not coinfected with C. trachomatis/N. gonorrhoeae (19% vs 13%; OR, 1.48; 95% CI, 0.30–7.24); no patient with M. genitalium was coinfected with N. gonorrhoeae. Only 2 patients with M. genitalium had a history of C. trachomatis/N. gonorrhoeae infection and azithromycin/ceftriaxone treatment in the prior 3 months. Although no one reported symptoms of an STI at their screening visit, 31% reported a STI symptom during the interval between their last and current screening visit (median, 356.0 days; IQR, 236.0–365.0 days); a greater proportion of M. genitalium–positive patients reported a symptom compared with patients positive for C. trachomatis/N. gonorrhoeae (32% [6 of 19] vs 13% [2 of 15], respectively).
A majority of M. genitalium–positive patients (n = 15) had negative urine leukocyte esterase levels; of 3 patients with trace leukocyte esterase levels, only 1 had a total of 5 urinary white blood cells per high-power field. The prevalence of M. genitalium was higher among patients with HIV infection diagnosed within the past year than among those whose HIV infection was diagnosed >1 year before M. genitalium positivity (25% vs 14%). A majority (95%) of M. genitalium–positive patients reported having had sexual contact in the past year with male partners and had higher odds of infection than patients with no partners or female partners in the past year (OR, 8.21; 95% CI 1.04–64.81, P = .046) and 58% reported having new partners and had higher odds of infection than those who did not report new partners (OR, 2.43; 95% CI, 0.88–6.70; P = .09).
DISCUSSION
This is the first report in the United States to describe the results of incorporating M. genitalium as part of standard STI screening for HIV-infected patients. The prevalence of M. genitalium was high and substantially higher than the prevalences of C. trachomatis, N. gonorrhoeae, and T. vaginalis among USAF patients with newly diagnosed or chronic HIV infection who were stationed throughout the United States and receiving HIV specialty care at a central medical facility. M. genitalium was detected most commonly in rectal samples, among patients with recently diagnosed HIV infection, as well as patients who reported having male sex partners in the past year.
In men, M. genitalium has been associated consistently with both nongonococcal urethritis (NGU) and nonchlamydial NGU, with nonchlamydial NGU prevalence ranging from 10% to 35% and with a higher prevalence among those reporting symptoms [9, 10]. Comparatively, the prevalence among men and women in the general population has ranged from 1% to 3.3% [10]. Similarly, and unlike the findings for C. trachomatis or N. gonorrhoeae, HIV-infected men bear a higher burden of M. genitalium than uninfected men, which reportedly has been at least 8 times higher in 1 study [11].
Our preliminary findings of an overall M. genitalium prevalence of 18.6%, and 24.0% among patients reporting MSM risk in the past year, are consistent with the findings of a study among asymptomatic HIV-infected men in China in which M. genitalium prevalence was 25.5% among men reporting same-sex acquisition of HIV and 28.8% among those who acquired HIV heterosexually; in that study only urine specimens were tested for M. genitalium [12]. Comparatively, in Guangdong province, China, M. genitalium prevalence in urine specimens from largely asymptomatic HIV-uninfected MSM was 7.6% [13]. Various reasons have been cited for the disproportionate burden and include (1) the association of more sexual partners among HIV-infected men with M. genitalium infection, (2) a hypothesis that T-cell deficiency in rectal mucosa may contribute to susceptibility to M. genitalium, and (3) the association of M. genitalium with HIV infection [11, 14].
Among HIV-infected patients, M. genitalium was more commonly detected among those whose HIV infection was recently diagnosed. This may be related to the immune status of these patients compared with chronically infected patients receiving antiretroviral therapy, with associated viral load suppression and immune reconstitution. Median CD4 cell counts were slightly lower among patients with HIV infection diagnosed ≤2 years ago than among those with a diagnosis for >2 year (671.5 cells/µL vs 830.5 cells/µL, respectively; P > .05).
Alternatively, M. genitalium infection may have played a role in acquisition of HIV. In a meta-analysis of cross-sectional studies that examined the association of M. genitalium and HIV infection, individuals with M. genitalium were found to have an overall 2-fold higher odds of HIV infection, with a stronger association among those in sub-Saharan Africa [15]. This effect also was seen in a longitudinal study of women, recruited from family planning and STI clinics, and sex worker networks; this study found an overall M. genitalium prevalence ranging from 6.5% to 14.9%, and women with M. genitalium had a ≥2-fold higher risk of HIV acquisition than those without M. genitalium [14].
Routine extragenital screening and treatment of identified C. trachomatis and N. gonorrhoeae infections was initiated in February 2013 as part of routine HIV care among USAF HIV-infected patients. Although this therapeutic practice may have cleared prevalent M. genitalium infection in patients with chronic HIV infection and may account for a higher prevalence of M. genitalium among patients with recently diagnosed HIV infection who were not routinely screened for C. trachomatis and N. gonorrhoeae, the low prevalence of M. genitalium and C. trachomatis/N. gonorrhoeae coinfection suggests otherwise. Whether there is a significant relationship between M. genitalium infection and factors such as duration of HIV infection and history of C. trachomatis/N. gonorrhoeae remains to be determined with a larger cohort of patients. In conclusion, preliminary findings from enhanced STI screening of HIV-infected individuals revealed a high prevalence of M. genitalium and low prevalence of T. vaginalis. Screening for and treatment of M. genitalium should therefore be considered in routine HIV care.
Notes
Acknowledgments. We are grateful to laboratory staff members Ashley Shutt and Catherine Stewart for their efforts in validating M. genitalium assays for extragenital samples.
Disclaimer. The views, opinions and/or findings contained in this report are those of the authors and should not be construed as an official position, policy or decision of the Department of the Army, Brooke Army Medical Center, the US Army Medical Department, the US Army Office of the Surgeon General, the Department of the Air Force, Department of Defense or the US government unless so designated by other documentation.
Financial support. This work was supported by the US Army Medical Research and Materiel Command (contract W81XWH-16-C-0225) and by a cooperative agreement (W81XWH-11-2-0174) between the Henry M. Jackson Foundation for the Advancement of Military Medicine and the US Department of Defense.
Potential conflicts of interest. All authors: No reported conflicts of interest. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.
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