Chlamydia trachomatis: WRONG Target for
Sexually Transmitted Diseases (STD) in Hong Kong!
Clement Leung-kwok CHAN
MBBS (HK), ECFMG (USA), AMC (Aust), MD (S’pore), FRCOG (UK),
FRANZCOG (Aust/NZ), FHKCOG (HK), FHKAM (OG),
FAMS (S’pore), FICS (USA), FACS (USA)
1. Director, Women’s Health And Reproductive Medicine (WHARM)
Centre, Hong Kong
2. Hon. Clinical Assoc. Professor, Dept. of O & G, Hong Kong
University, Hong Kong
3. Hon. Clinical Assoc. Professor, Dept. of O & G, Chinese
University of Hong Kong Hong Kong
4. Adjunct Assoc. Professor, School of Biomedical Sciences,
Chinese University of Hong Kong Hong Kong
5. Visiting Professor, Cebu Institute of Medicine, Philippines
6. Asian Federation Secretary & Executive Board Member,
International College of Surgeons, USA
7. Ex-Chairman & Professor, University of Tasmania, Australia
Chlamydia trachomatis: WRONG Target for
Sexually Transmitted Diseases (STD) in Hong Kong!
Clement Leung-kwok CHAN
MBBS (HK), MD (S’pore), FRCOG (UK), FRANZCOG (Aust/NZ), FHKCOG
(HK), FHKAM (OG)
1. Consultant, Women’s Health And Reproductive Medicine (WHARM) Centre,
Hong Kong
2. Adjunct Assoc. Professor, School of Biomedical Sciences, Chinese University
of Hong Kong, Hong Kong
Wai Yee CHAN BSc (CUHK), PhD (Florida)
Director & Professor, School of Biomedical Sciences, Chinese University of
Hong Kong, Hong Kong
Chrssitopher CHENG Bsc (CUHK), PhD (Lond)
Professor, School of Biomedical Sciences, Chinese University of Hong Kong,
Hong Kong
Chlamydia urethritis
Chlamydia trachomatis: WRONG Target for
sexually transmitted disease in Hong Kong?
-Chlamydia trachomatis- obligate intracellular human pathogen, is 1
of 3 species in genus Chlamydia.
- Gram (-) bacteria, therefore cell wall components retain the
counter-stain safranin & appear pink under light microscope
- appear as either coccoid or rod shape
- inclusion bodies of C trachomatis 1st described 1942
- 1st cultured in yolk sacs of eggs by Prof.Feifan Tang et al in 1957
- 3 human biovars:
a) Serovars Ab, B, Ba, or C  trachoma (infection of eyes 
blindness , prevalent in Africa)
b) serovars D-K  urethritis, pelvic inflammatory disease, ectopic
pregnancy, neonatal pneumonia & neonatal conjunctivitis
c) serovars L1, L2 & L3  lymphogranuloma venereum(LGV)
- Many, but not all strains have an extrachromosomal plasmid
Chlamydia trachomatis: WRONG Target for
sexually transmitted disease in Hong Kong?
Chlamydia trachomatis:
1) Both sexes - urethritis, proctitis (rectal disease and
bleeding), trachoma & infertility.
2) Men- prostatitis & epididymitis
3) Women- cervicitis, pelvic inflammatory disease (PID),
ectopic pregnancy (EP), & acute or chronic pelvic pain
4) Neonate- trachoma & pulmonary Cx
-single most important infectious agent associated with
blindness;
- ≈ 600 M worldwide - C. trachomatis eye infections 
20 M blindness
Chlamydia trachomatis: WRONG Target for
sexually transmitted disease in Hong Kong?
Tests for Chlamydia trachomatis:
1) Nucleic acid amplification tests (NAAT)
 chlamydia DNA; e.g polymerase chain reaction (PCR) -can use urine
- most sensitive, very accurate & very unlikely false-negative
2) Nucleic acid hybridization tests (DNA probe test)
 Also chlamydia DNA- very accurate but not as sensitive
3) Enzyme-linked immunosorbent assay (ELISA, EIA)
- quick test finds chlamydia antigens
4) Direct fluorescent antibody test (DFA).
- quick test also finds chlamydia antigens.
5) Chlamydia cell culture.
-suspected chlamydia sample grown in a vial of cells in laboratory. The
pathogen infects the cells and after a set incubation time (48 hours) the
vials are stained and viewed on a fluorescent light microscope.
- more expensive, longer time (2 days)
Chlamydia trachomatis: WRONG Target for
sexually transmitted disease in Hong Kong?
-Chlamydial genital infection - most common bacterial STD in USA
(Cates W. Sex Transm Dis 1999; 26:S2–7)
- prevalence highest in persons </ =25 yrs of age (Centers for Disease
Control & Prevention. STD surveillance 2002 suppl. Chlamydia Prevalence
Monitoring. Project Ann Report 2002. Atlanta, GA: US Dept of Health & Human
Services, Centers for Disease Control & Prevention, Oct 2003)
- also commonest curable STD in England &Wales (Taylor-Robinson D.
BMJ 1994; 308: 150-151) (Sexually transmitted diseases quarterly report.
Communicable Dis Rep 1995; 5: 122-123)
- Asymptomatic (up to 70%); common among both sex; is one of main
causes of pelvic inflammatory disease (PID) in developed world (Cates
W, Wasserheit JN. AJOG 1991; 164: 1771-81)
- PID infertility, ectopic pregnancy (EP) & miscarriage (US Dept of
Health & Human Services. Morbidity MortalityWeekly Rep 1993; 42: 1-38)
(Oakeshott P, Hay P. Br J Gen Pract 1995; 45: 615-20)
Chlamydia trachomatis: WRONG Target for
sexually transmitted disease in Hong Kong?
-detection often relies on screening
- Centers for Disease Control & Prevention (CDC) & US
Preventive Services Task Force each recommend annual
chlamydial screening for
a) all sexually active women </=25 yrs of age &
b) older women with risk factors (e.g. new or multiple sex partners)
(CDC & Prevention. STD treatment guidelines 2002. MMWR Recomm Rep 2002;
51(RR-6):1–78) (US Preventive Services Task Force. Screening for chlamydial
infection: recommendations & rationale. Am J Prev Med 2001; 20(Suppl 3): 90–
4)
- estimated cost of Dx & Mx genital chlamydia & its Cx in UK 
> £50 M /yr (Taylor-Robinson D. BMJ 1994; 308: 150-151) (Sexually transmitted
diseases quarterly report. Communicable Dis Rep 1995; 5: 122-123)
Chlamydia trachomatis: WRONG Target for
sexually transmitted disease in Hong Kong?
Screening programs in women 
a)  prevalence of chlamydia (Mertz KJ etal. Sex Transm Dis 1997;
24:169–75) (Centers for Disease Control and Prevention. Chlamydia trachomatis
genital infections United States, 1995. MMWR Morb Mortal Wkly Rep 97;
46:193–8) &
b) rates of PID (Scholes D et al. NEJM 96; 334:1362–6) (Kamwendo F et
al. STD 96; 23:384–91)
Chlamydia trachomatis: WRONG Target for
sexually transmitted disease in Hong Kong?
Mx of uncomplicated genital chlamydial infection in adults
1)Px of patients   Cx & prevent transmission to partners
2)Px of sex partners  prevent reinfection of index patient &
infection of other partners
3)risk-reduction counselling, &
4)repeat chlamydial testing few months after Px (to detect
failure/recurrent / persistent infections).
Ureaplasma
Mycoplasma
Chlamydia trachomatis: WRONG Target for
sexually transmitted disease in Hong Kong!
Ureaplasma & Mycoplasma
(Bryan Larsen,Joseph Hwang. Infect Dis Obstet Gynecol. 2010;2010. pii: 521921)
- Mycoplasma hominis, Ureaplasma urealyticum for several
decades - among experts in genital tract infectious disease with
indications that former can be part of normal flora of
sexually experienced women & both may chorioamnionitis,
salpingitis, bacterial vaginosis, & postpartum endometritis.
- availability of molecular methods substantially  valid
information about the pathogenic potential of these bacteria
which lack rigid cell walls (Molicutes, specifically the family
Mycoplasmataceae)
- Mycoplasma hominis & Ureaplasma urealyticum have
historically been the subject of attention, but Mycoplasma
genitalis  male urethritis & colonizing female genital tract
- Ureaplasma - two species, urealyticum & parvum
Chlamydia trachomatis: WRONG Target for
sexually transmitted disease in Hong Kong!
Viscardi RM. Ureaplasma species: role in neonatal morbidities and outcomes. Arch
Dis Child Fetal Neonatal Ed. 2014;99:F87-92.
-In our institution, ≈ 50% preterm infants < 32 wk Ureaplasma
(+) in >/= 1 compartment (respiratory, blood &/or CSF)
 most common pathogens affecting population.
-compelling epidemiological & experimental evidence linking
perinatal Ureaplasma species exposure to important morbidities
of prematurity, e.g. bronchopulmonary dysplasia,
intraventricular haemorrhage & necrotising enterocolitis
Chlamydia trachomatis: WRONG Target for
sexually transmitted disease in Hong Kong!
Capoccia R et al. Ureaplasma urealyticum, Mycoplasma hominis and adverse pregnancy
outcomes. Curr Opin Infect Dis. 2013;26:231-40.
- review recent data on epidemiology & clinical role in
pregnancy many observational studies assoc. with
preterm labour, but proof of causality remains limited.
- PCR- excellent (cf culture) for Dx, but culture  CST.
- ?? Px effectively  adverse pregnancy outcomes more Ix
SUMMARY:
1) Mycoplasma & U. urealyticum  adverse pregnancy
outcomes is increasingly accepted.
2) However, sole presence of these in vaginal flora might be
insufficient to cause pathological issues, but + other factors
(e.g. bacterial vaginosis or cervical incompetence) may be
additionally needed  preterm birth
Chlamydia trachomatis: WRONG Target for
Sexually Transmitted Diseases (STD) in Hong Kong!
Aims of study
1)Is Chlamydis trachomatis the most prevalent
organism in HK?
2)What are the relative prevalence of the various
STD organisms?
3)For male, which is the more sensitive method of
collection of specimen, semen or urine?
Chlamydia trachomatis: WRONG Target for
Sexually Transmitted Diseases (STD) in Hong Kong!
Methods and Materials
- from 1 July 2005 to 30 June 2013  8 yr solo private practice
- Patient selection:
1) Subfertility or discharge - initial screen - C trachomatis & U
urealyticum DNA for females (Real Time PCR using Applied
Biosystem 7500- based on 36% prevalence of infection, sensitivity,
specificity, PPV & NPV = 87, 96, 94, & 93% respectively);
- only if anyone is (+), then counsel COUPLE, explain to couples to
do STD full check package ( DNA for C. trachomatis, U urealyticum,
M hominis, N gonorrhoea; VDRL or RPR for syphilis; Herpes I & I
IgG; HIV only on request)
Chlamydia trachomatis: WRONG for
Sexually Transmitted Diseases (STD) in Hong Kong!
Methods and Materials
2) Pelvic (or genital) infection, or pain- counsel Patient, explain &
suggest: do STD full check package
- RPR: ASI RPR Card Test for Syphilis, which is a qualitative and
semi-quantitative non-treponemal flocculation test for the detection
of regain antibodies in human serum and plasma as a screening test
in syphilis serology.
- HSV II Antibody IgG: Euroimmun Anti-HSV-2 (gG2) ELISA (IgG)
kit. The kit is claimed to have 95.5% specificity and 100% sensitivity
HSV I Antibody IgG: Euroimmun Anti-HSV-1 (gC1) ELISA (IgG)
kit. The kit is claimed to have 100% sensitivity and specificity
Overall Percentage of C. trachomatis DNA & U. urealyticum DNA (including
patients who have either the SCREENING or FULL STD CHECK)
Chlamydia
trachomatis
Ureaplasma
urealyticum
P-value
FEMALE
48/862
(5.57%)
334/901
(37.07%)
< 0.001
MALE
10/177
(5.65%)
40/289
(13.84%)
0.006
P-value
0.966
< 0.001
TOTAL:
1,039 cases
1,190 cases
STD in Relation to Patient’s Indication
Chlamydia Neisseria Mycoplasma Ureaplasma
trachomatis gonorrhoea
hominis
urealyticum
VDRL/
RPR
HSV II
IgG
HSV I
IgG
PELVIC
DISCOMFORT
10/81
(12.35%)
10/92
(10.87%)
0/81
(0.00%)
1/92
(1.09%)
10/81
(12.35%)
13/92
(14.13%)
9/81
(11.11%)
36/92
(39.13%)
0/81
10/81
58/81
(0.00%) (12.35%) (71.60%)
1/92
21/92
78/92
(1.09%) (22.83%) (84.78%)
SUBFERTILITY
19/343
(5.54%)
4/343
(1.17%)
46/343
(13.41%)
139/343
(40.52%)
3/343
67/343 247/343
(0.87%) (19.53%) (72.01%)
VAGINAL
DISCHARGE
4/63
(6.35%)
0/63
(0.00%)
10/63
(15.87%)
26/63
(41.27%)
0/63
10/63
53/63
(0.00%) (15.87%) (84.13%)
UNCLASSIFIED
1/41
(2.44%)
0/41
(0.00%)
6/41
(14.63%)
10/41
(24.39%)
0/41
10/41
26/41
(0.00%) (24.39%) (63.41%)
TOTAL
44/620
(7.1%)
5/620
(0.8%)
85/620
(13.7%)
220/620
(35.5%)
4/620
(0.64%)
0.200
0.708
0.979
< 0.001
0.779
INFECTION*
P-value
118/620 462/620
(19%) (74.5%)
0.350
0.015
% of Frequency
C. trachomatis
22/620 (3.55%)
N. gonorrhoea
1/620 (0.16%)
U. urealyticum
173/620 (27.90%)
M. hominis
47/620 (7.58%)
C. trachomatis + U. urealyticum
13/620 (2.10%)
C. trachomatis + M. hominis
6/620 (0.97%)
N. gonorrhoea + U. urealyticum
4/620 (0.65%)
U. urealyticum + M. hominis
27/620 (4.35%)
C. trachomatis + U. urealyticum + M.
hominis
4/620 (0.65%)
All negative
323/620 (52.10%)
PAIRED COUPLE WITH COMPLETE STD PROFILE
Chlamydia Neisseria Mycoplasma Ureaplasma RPR/
HSV II
trachomatis gonorrhoea hominis urealyticum Syphilis
IgG
14/127
FEMALE (11.03%)
HSV I
IgG
3/127
(2.36%)
23/127
(18.11%)
83/127
1/127 29/127 100/127
(65.35%) (0.79%) (22.83%)(78.74%)
MALE
4/127
(3.15%)
0/127
(0%)
16/127
(12.60%)
31/127
1/127 18/127 86/127
(24.41%) (0.79%) (14.17%)(67.71%)
p-value
0.014
0.247
0.223
< 0.001
Comment : this slide should be paired analysis.
P –values are based on unpaired
1.0
0.076
0.047
Semen vs urine
Chlamydia Neisseria Mycoplasma Ureaplasma RPR/
trachomatis gonorrhoea hominis
urealyticum Syphilis
HSV II
IgG
HSV I
IgG
semen
10/166
(6.02%)
0/166
(0.00%)
21/166
(12.65%)
31/166
(18.67%)
1/166
24/166 111/166
(0.60%) (14.46%) (66.87%)
urine
1/21
(4.76%)
0/21
(0.00%)
2/21
(9.52%)
5/21
(23.81%)
0/21
4/21
14/21
(0.00%) (19.05%) (66.67%)
P-value
0.512
-
0.981
0.674
other
doctors
(urine
sample)
0/11
(0.00%)
0/11
(0.00%)
2/11
(18.19%)
2/11
(18.19%)
Total: 199 cases
1.0
0.670
0.640
0/11
2/11
7/11
(0.00%) (18.19%) (63.64%)
Chlamydia trachomatis: WRONG for
Sexually Transmitted Diseases (STD) in Hong Kong!
SUMMARY:
Chlamydia trachomatis
Neissera gonorrhoea
Mycoplasma hominus
Ureaplasma urealyticum
Syphilis
HSV I IgG
HSV II IgG
7.4%
0.8%
14%
35.3%
0.5%
74.2%
18.7%
Chlamydia trachomatis: WRONG for
Sexually Transmitted Diseases (STD) in Hong Kong!
CONCLUSION:
1 ) Chlamydia trachomatis incidence is much lower than U
urealyticum, M hominus
2) This is more obvious in those presenting with pelvic pain cf
subfertility
3) Guideline in testing C trachomatis should be changed to U
urealyticum, M hominus (with/ without C trachomatis & N
gonorhoea)
4) Apparently, there is no significant difference using urine or semen
specimen
Chlamydia trachomatis: WRONG for
Sexually Transmitted Diseases (STD) in Hong Kong!
Problems to solve:
1) How to diagnose Upper Genital Tract infection?
2) Role of U parvum?
3) More sensitive & specific tests?
4) Efficacy of different treatment regimes?
Chlamydia trachomatis: WRONG for
Sexually Transmitted Diseases (STD) in Hong Kong!
THANK YOU