A case report of proctitis associated with Mycoplasma genitalium in a man who has sex with men

Case report

A 49-year-old man who has sex with men (MSM) presented with anal pain, tenesmus and bloody discharge for eight days, without systemic symptoms. During the previous three months, he reported having had sex with nine partners, including condomless anal sex two weeks before the visit. He was on antiretroviral therapy with a well-controlled HIV infection. He had previously had gonorrhoea and eight months before the visit he had been diagnosed of hepatitis C and secondary syphilis. At the time of the visit he was not receiving treatment for hepatitis C and his laboratory results were: HIV viral load <40 copies/mL, CD4 cell count 963cells/ mm³ (33.2%), hepatitis C virus (HCV) viral load 218,867 UI/mL and rapid plasma reagin (RPR) 1:2. The patient had no other relevant medical history including anal conditions.

At physical examination he had no cutaneous, genital or perianal lesions and no inguinal nodes enlargement. Proctoscopy showed an erythematous rectal mucosae and mucopurulent exudate with blood. A rectal Gram stain showed 25 polymorphonuclear cells per high-powerfield without Gram-negative diplococci. Empirical treatment of proctitis was started with doxycycline 100 mg twice daily for seven days. The timeline of events is shown in Table 1. Nucleic acid amplification tests from rectum were negative for Chlamydia trachomatis, Neisseria gonorrhoeae, herpes simplex virus and Treponema pallidum but positive for Mycoplasma genitalium. His RPR test was 1:8. The patient improved after seven days of treatment with doxycycline but the tenesmus persisted. By then he started treatment with azithromycin 500 mg oral as a single dose followed by 250 mg oral once daily for four days. Three weeks later the patient reported only mild abdominal discomfort. A test of cure for M. genitalium remained positive. At that time he was treated for early latent syphilis with benzathine penicillin G 2.4 million units IM as a single dose. Two weeks later, moxifloxacin 400 mg oral once daily for seven days was started. During the following four months, the patient remained asymptomatic and his rectal M. genitalium tests were negative. Retrospectively, only the sample of day 0 was available for antimicrobial resistance testing and macrolide-resistance was found. Although contact tracing was advised, it could not be known if partners were tested or if reinfection could have occurred during the study period.

OPEN IN VIEWER

Table 1.

Timeline of clinical, laboratory and treatment events in a case of M. genitalium proctitis.

Symptoms of proctitis	+++	++	+	0	0	0
M. genitalium	Positive		Positive		Negative	Negative
RPR	1:8		1:16		1:8	Negative
Treatment	Doxycycline 100 mg twice daily for seven days	Azithromycin 500 mg stat followed by 250 mg daily for four days	Benzathine penicillin G 2.4 million units	Moxifloxacin 400 mg once daily for seven days
Day	0	8	29	49	72	192

Discussion

Mycoplasma genitalium is becoming an infection of increasing concern due to its potential to cause reproductive tract sequelae and its development of antimicrobial resistance. In many Western countries azithromycin resistance approaches 50%. About 10% of patients infected by macrolide-susceptible M. genitalium may develop resistant infections after this treatment, which is caused by a single-base mutation in region V of the 23S rRNA.¹ M. genitalium is an established pathogen that causes urethritis and increases the risk of cervicitis and pelvic inflammatory disease. ² Although its role as a cause of proctitis has not been defined, some literature about this is emerging. Bissessor et al. conducted a prospective study in MSM presenting with symptomatic proctitis and M. genitalium was detected in 12% of cases. HIV-positive men were significantly more likely to have this rectal infection than HIV-negative men (21% versus 8%). Moreover, in symptomatic patients the median load of the microorganism was higher than in asymptomatic rectal infection. ³ Similar results were previously obtained in a clinical cross-sectional survey of MSM in San Francisco. ⁴ Ong et al. described that proctitis caused by M. genitalium were less symptomatic than those cases caused by C. trachomatis or N. gonorrhoeae and, additionally, M. genitalium was more prevalent among symptomatic MSM compared to asymptomatic ones. ⁵ The case presented shows the association of M. genitalium as a possible cause of proctitis, since it was the only pathogen found after excluding other infections known to cause sexually acquired infectious proctitis. The patient improved after treatment and the test of cure was negative.

Previous studies conducted among asymptomatic MSM reviewed by Bissessor et al. showed that prevalence rates of rectal M. genitalium were not higher than 5%. ³ The same rate, with low bacterial loads, was also found in a recent study from Italy. ⁶ Nonetheless, we found a prevalence of 8.7% among 461 asymptomatic MSM reporting anal sex, tested in a rapid screening service in our setting during 2017–2018.⁷ Although M. genitalium has a similar prevalence to C. trachomatis, screening cannot be systematically recommended. M. genitalium’s natural history is still poorly understood, making screening’s effectiveness unclear and there is concern about drug toxicity and increasing antimicrobial resistance to macrolides and also to second-line therapies.^8,9 Some authors recommend to avoid identifying M. genitalium in asymptomatic infections due to the consequent imperative need to treat it and to undertake contact tracing. ¹⁰ The rationale for the clinical need for diagnosing M. genitalium infection has been debated. ¹¹ So far the indications for testing it in Europe are: patients with defined symptoms – including proctitis (with low level of evidence) – and their partners. ² As more data are appearing, proctitis might become a stronger indication for testing M. genitalium, together with antimicrobial resistance-guided therapy. ¹²

Herein we presented a case of a HIV- and HCV-positive MSM with proctitis caused by M. genitalium, who also had latent syphilis, showing the need to take into account M. genitalium as a cause of proctitis in people with high-risk sexual behaviour.