Dr Darshani Wijewickrama

1. STI diagnosis among
MSM
Dr. Darshani Wijewickrama
Acting Venereologist,
Teaching Hospital, Mahamodara

2. Overview
1. STI situation among MSM
2. Special issues related to MSM
3. Recommendations for testing

3. 1.STI situation among MSM
• Higher risk of acquiring HIV
- MSM are 19.3 times more likely to be HIV
infected than the general population¹
- Asia- the odds of MSM being infected with HIV
is 18.7 times higher than the general
population¹

4. Comparison of prevalence of STIs among HIV
positive and negative MSM
(2011 STD surveillance –CDC)
STI HIV positive HIV negative
Primary + secondary
syphilis
10.1% 2.6
Urethral gonorrhoea 12.5% 9%
Pharyngeal gonorrhoea 6.6% 5.55
Rectal gonorrhoea 12.9% 7.2%
Urethral Chlamydia 8.3% 7.4%
Rectal Chlamydia 20.6% 10.8%
Anal cancer 0.35% 0.07%

5. • High STI prevalence
Data from US
-MSM accounted for 75% of all primary and
secondary syphilis cases in 49 states in US¹ in
2013
- Proportion of isolates from MSM in selected STD
clinics from GISP sentinel sites has increased
steadily, from 4.6% in 1990 to 35.1% in 2013¹

6. Data from GUM clinics in UK
-42% of gonorrhoea diagnoses- among MSM²
-Chlamydia co-infection common among them²
-Increased LGV prevalence

7. • Data from Colombo, Sri Lanka
Syphilis prevalence among MSM
Sample proportions Population estimates
Syphilis (active) 1.8% 2.4% (0.3-4.6)
Syphilis (non active) 3.8% 3.2% (1.7-4.7)
Syphilis (total) 5.6% 5.6 (3.0-8.2%)

8. 2. Special issues related to MSM
i. Asymptomatic infections
ii. Issues related to diagnostic tests
A. Sensitivity and specificity
B. NAATs not being licensed for some sites
C. New variant Chlamydia trachomatis
D. Need of well equipped laboratories

9. - A study of STI prevalence among MSM with
HIV, revealed a 14% prevalence of
asymptomatic syphilis and gonorrhoea and
Chlamydia infections in pharynx, rectum,
urethra.
i. Asymptomatic infections

10. • Asymptomatic gonorrhoea
-rectal infections-usually asymptomatic
-pharyngeal infections->90% asymptomatic
• Asymptomatic Chlamydia infection
-urethral infections asymptomatic in >50% men
-rectal infections –usually asymptomatic

11. • Asymptomatic LGV infection
-Some studies from Europe found that up to
95% of rectal LGV cases were asymptomatic.
- one series from a large London centre found a
higher proportion of asymptomatic rectal LGV
(17.8%)

12. A. Sensitivity and specificity
• Microscopy in gonorrhoea
- Sensitivity of urethral smears
in asymptomatic men-50-70%
-sensitivity in anoscopically
obtained specimen in symptomatic
rectal infection-70-80%
-Not recommended for
asymptomatic rectal infections
and pharyngeal specimens
ii. Issues related to diagnostic tests

13. • Microscopy in syphilis
-less reliable in rectal
lesions
-not recommended for
oral lesions

14. • NAAT in gonorrhoea
-Sensitivity>96% in both symptomatic and
asymptomatic infection
-Screening –less beneficial where gonorrhoea
<1% (otherwise PPV will be low)
-A supplementary test is needed to confirm a
positive result from low prevalence
populations and for specimens from the
rectum or pharynx;

15. • NAAT in Chlamydia infection
- every positive Chlamydia result should be
confirmed using a NAAT
-preferably with an assay of
equal sensitivity+ different target.
- Recent data suggests that confirmatory testing
may be unnecessary if >90% of positive NAAT
results will be confirmed. Further work is
required to validate this strategy for extra-
genital specimens

16. • NAAT in LGV
- positive samples should be confirmed by real-
time PCR for LGV-specific DNA in cases of
suspected LGV and have been sourced from
either a symptomatic patient or a direct
sexual contact.

17. B. NAATs being not licensed for pharyngeal and
rectal specimens.
-Potentially gives valid results
- Commercially available NAATs differ in their
cross-reactivity to comensal Neisseria species
which may be present at significant levels at
anus particularly in pharynx

18. C. New variant C.trachomatis
-A C. trachomatis strain with a deletion in the
cryptic plasmid was discovered in Sweden
- resulted in false negative results.
- The target sequence of some commercially
available kits has since been modified, but not
all kits are capable of detecting the nvCT.

19. D. Need of well equipped laboratories
- NAAT - broadly implemented in the
developed world as the preferred
methodology for N. gonorrhoeae and
C.trachomatis
- Less available in developing countries

20. 3. Recommendations for testing
asymptomatic MSM
WHO recommendations
• Offering periodic testing for asymptomatic
urethral and rectal N. gonorrhoeae and C.
trachomatis infections using NAAT is
suggested over not offering such testing for
MSM.
(Conditional recommendation, low quality of
evidence)

21. • Not offering periodic testing for asymptomatic
urethral and rectal N. gonorrhoeae infections
using culture is suggested over offering such
testing for MSM.
(Conditional recommendation, low quality of
evidence)

22. • Offering periodic serological testing for
asymptomatic syphilis to MSM is strongly
recommended over not offering such
screening.
(Strong recommendation, moderate quality of
evidence)

23. Recommendations for testing
asymptomatic MSM
CDC 2015 STD Guidelines
The following screening tests should be
performed at least annually for sexually active
MSM
- HIV serology, if HIV status is unknown or
negative and the patient or his sex partner(s)
has had >1 one sex partner since most recent
HIV test.
- Syphilis serology

24. - A test for urethral gonorrhoea and Chlamydia
infection in men who have had insertive sex
during preceding year
- A test for rectal gonorrhoea and Chlamydia
infection in men who have had receptive anal
sex during preceding year

25. - A test for pharyngeal infection with N.
gonorrhoeae in men who have had receptive
oral sex during preceding year .
- Testing for C. trachomatis pharyngeal
infection is not recommended because of the
low prevalence.

26. -Hep B surface Ag testing
-Screening for HCV specially –HIV positive MSM
Screening should be performed using HCV
antibody assays followed by HCV RNA testing
for those with a positive antibody result

27. - In a recent meta-
analysis, there was no
statistically significant
difference in the
prevalence of HGAIN
between HIV-infected
and HIV-uninfected
MSM

28. -It is highly likely that regression of HGAIN
occurs even with HIV infection, as with CIN
-However, no published estimates of regression
rates, or risk factors for regression compared
with HGAIN persistence or progression to
cancer.

29. - Data are insufficient to recommend routine
anal-cancer screening with anal cytology in
HIV positive or negative MSM. However, some
clinical centres perform anal cytology to
screen for anal cancer among HIV positive
MSM, followed by high-resolution anoscopy
for those with abnormal cytologic results (e.g.,
ASC-US).