Characteristics of the study participants
During the 17-month study period, 727 individuals were recruited, 49 of whom were excluded due to missing data. A total of 678 patients—489 (72%) men and 189 (28%) women—were finally included in the present study. The mean age of the study population was 34.02 ±13.39 years (33.70±9.23 years for the men and 34.83±20.35 years for the women. Of the 489 men, 41 (6%) identified as gay and 8 (1%) as bisexual. None of the women identified themselves as lesbian or bisexual. Half of the participants were married, and 66% had completed higher education. Most (77%) had been living in Guangzhou for more than six months.
Among the 678 participants, 127 (14.2%) were symptomatic; 15.9% (108/678) of these were men, and 2.8% (19/678) were women. Other patient characteristics and MG test results are shown in Table 1.
Table 1. Demographic and behavioural characteristics of study participants attending the hospital STI clinic in Guangzhou,(n=678)
Characteristics
|
Total
|
MG positive n (%) (percentage of individuals with the characteristic)
|
P value
|
Sex
|
|
|
0.827
|
Male
|
489
|
36 (7.36, 5.04-9.68)
|
|
Female
|
189
|
13 (6.88, 3.24-10.52)
|
|
Age (years)
|
|
|
0.158
|
18-25
|
136
|
15 (11.03, 5.70-16.36)
|
|
26-45
|
474
|
30 (6.33, 4.13-8.53)
|
|
>45
|
68
|
4 (5.88, 0.15-11.62)
|
|
Marital status
|
|
|
0.264
|
Single
|
309
|
23 (7.44, 4.50-10.39)
|
|
Currently married
|
342
|
22 (6.43, 3.822-9.05)
|
|
Other
|
27
|
4 (14.81, 0.49-29.14)
|
|
Time at local residence
|
|
|
0.258
|
Less than 6 months
|
155
|
8 (5.16, 1.64-8.68)
|
|
More than 6 months
|
523
|
41 (7.83, 5.53-10.15)
|
|
Education level
|
|
|
0.329
|
Middle school or less
|
119
|
5 (4.20, 0.54-7.86)
|
|
Senior school
|
109
|
8 (7.34, 2.37-12.31)
|
|
Secondary school or junior college
|
203
|
13 (6.40, 3.00-9.80)
|
|
Bachelor’s degree or higher
|
247
|
23 (9.31, 5.66-12.96)
|
|
Sexual orientation
|
|
|
0.377
|
Heterosexual
|
629
|
47 (7.47, 5.41-9.53)
|
|
MSM
|
49
|
2 (4.08, 0.00-9.82)
|
|
Condom use in P6m
|
|
|
0.035
|
Always
|
76
|
1 (1.32, 0.00-3.94)
|
|
Not always
|
602
|
48 (7.97, 5.80-10.14)
|
|
Sexual partners in *P6m
|
|
|
0.474
|
0-1
|
368
|
23 (6.25, 3.77-8.73)
|
|
2~3
|
262
|
21 (8.02, 4.71-11.32)
|
|
>3
|
48
|
5 (10.42, 1.45-19.38)
|
|
**Symptomatic
|
|
|
0.001
|
No
|
551
|
31 (5.63, 3.70-7.56)
|
|
Yes
|
127
|
18 (14.17, 8.02-20.32)
|
|
MG prevalence among and clinical characteristics of the infected patients
MG was detected in 7.2% (49/678) of all patients in the study, corresponding to a prevalence of 7.4% (36/489) among men and to 6.9% (13/189) among women. Mg was more likely to be detected among symptomatic patients, the MG positivity rate was 14.2% among symptomatic patients, and 5.6% for asymptomatic patients, respectively.
Among patients with MG infection, only 36.7% (18/49) were symptomatic, of whom 50.0% (9/18) were co-infected with CT and/or NG. For detailed clinical manifestations, 16.7% male patients with Mg infection had abnormal physical examination findings, 47.2% had self-reported symptoms, 33.3% presented with excess leucocytes with microscopic examinations. For female patients with Mg infection, the rates for abnormal physical examination findings, self-reported symptoms and presented with excess leucocytes under microscopic examinations were 0%, 15,5%, 53.8%, respectively. Clinical manifestations of Mg infected patients with or without other infections are shown in Table 2.
Table 2. Clinical manifestations of patients with MG who were coinfected with CT and/or NG ,(n=49)
aMG (%)
|
bCT&MG (%)
|
cNG&MG (%)
|
dNG&CT&MG (%)
|
Total (%)
|
Men (n=36)
|
|
|
|
|
|
|
Physical examination findings
|
No
|
27 (90.0)
|
2 (6.7)
|
1 (5.3)
|
0 (0)
|
30 (83.3)
|
Yes
|
3 (50)
|
0 (0)
|
2 (33.3)
|
1 (16.7)
|
6 (16.7)
|
Self-reported symptoms
|
No
|
17 (89.5)
|
1 (5.3)
|
1 (5.3)
|
0 (0)
|
19 (52.8)
|
Yes
|
13 (76.5)
|
1 (5.9)
|
2 (11.8)
|
1 (5.9)
|
17 (47.2)
|
Presence of excess leucocytes
|
No
|
24 (100)
|
0 (0)
|
0 (0)
|
0 (0)
|
24 (66.7)
|
Yes
|
6 (50)
|
2 (16.7)
|
3 (25)
|
1 (8.3)
|
12 (33.3)
|
Women (n=13)
|
|
|
|
|
|
|
Physical examination findings
|
No
|
10 (76.9)
|
3 (23.1)
|
0 (0)
|
0 (0)
|
13 (100)
|
Yes
|
0 (0)
|
0 (0)
|
0 (0)
|
0 (0)
|
0 (0)
|
Self-reported symptoms
|
No
|
9 (81.8)
|
2 (18.2)
|
0 (0)
|
0 (0)
|
11 (84.6)
|
Yes
|
1 (50)
|
1 (50)
|
0 (0)
|
0 (0)
|
2 (15.4)
|
Presence of excess leucocytes
|
No
|
6 (100)
|
0 (0)
|
0 (0)
|
0 (0)
|
6 (46.2)
|
Yes
|
4 (57.1)
|
3 (42.9)
|
0 (0)
|
0 (0)
|
7 (53.8)
|
a: MG infection; b: Chlamydia trachomatis infection; c: Neisseria gonorrhoeae infection; d: Chlamydia trachomatis and Neisseria gonorrhoeae infection
The data for co-infections in patients with MG infection are shown in Tables 2 and 3. According to our data, 10.2% of the patients were co-infected with CT (5/49), 6.1% with NG (3/49), 2.0% with both CT and NG (1/49), 8.2% with HSV-2 (4/49), 4.1% with TP (2/49) and 22.4% with GW (11/49).
Table 3. STI infections in patients with and without MG infection, (n=678)
aSTI
|
MG-negative
|
MG-positive
|
P value
|
bHIV
|
|
|
0.427
|
No
|
621 (92.7)
|
49 (7.3)
|
|
Yes
|
8 (100.0)
|
0 (0.0)
|
|
cCT
|
|
|
0.802
|
No
|
544 (92.7)
|
43 (7.3)
|
|
Yes
|
85 (93.4)
|
*6 (6.6)
|
|
dHSV-2
|
|
|
0.250
|
No
|
540 (92.3)
|
45 (7.7)
|
|
Yes
|
88 (95.7)
|
4 (4.3)
|
|
eTP
|
|
|
0.879
|
No
|
606 (92.8)
|
47 (7.2)
|
|
Yes
|
23 (92.0)
|
2 (8.0)
|
|
Genital warts
|
|
|
0.271
|
No
|
441 (92.1)
|
38 (7.9)
|
|
Yes
|
188 (94.5)
|
11 (5.5)
|
|
fNG
|
|
|
0.890
|
No
|
574 (92.7)
|
45 (7.3)
|
|
Yes
|
55 (93.2)
|
*4 (6.8)
|
|
aSexually transmitted infection; b Human immunodeficiency virus; c Chlamydia trachomatis; d Herpes simplex virus 2; e Treponema pallidum; f Neisseria gonorrhoeae. * One patient had MG&CT&NG coinfection.
Infection rates for other STIs among the study subjects
The infection rates of the other STIs among the study subjects were as follows: CT, 13.4% (91/678); NG, 8.8% (59/678); HSV-2, 13.7% (92/678); GW, 29.4% (199/678); and HIV, 1.2% (8/678). Twenty-seven patients were co-infected with MG and one other STI. Sixteen patients were co-infected with MG and more than one other STI. The detailed data are shown in Table 3.
Correlates of MG infections
Univariate logistic regression showed that symptomatic patients had a higher MG infection rate than asymptomatic patients (P=0.001). Furthermore, patients who reported not using a condom during all sexual encounters were more likely to be infected with MG than patients who reported using a condom during each sexual encounter in the past 6 months (P=0.035). Multivariable logistic regression showed that only clinical symptoms were associated with MG infection (Table 4). However, MG infection was not associated with other STIs, according to our analysis (Table 3).
Table 4. Regression analysis for factors associated with MG infection in Guangzhou, China, 2017-2018 (n=678)
|
MG
|
|
Univariate OR
|
P value
|
Multivariate OR
|
P value
|
Sex
|
|
|
|
|
Male
|
Ref
|
|
|
|
Female
|
0.93 (0.48-1.79)
|
0.827
|
|
|
Age (years)
|
|
|
|
|
18-25
|
1.98 (0.632-6.23)
|
0.241
|
|
|
26-45
|
1.08 (0.37-3.17)
|
0.887
|
|
|
>45
|
Ref
|
|
|
|
Marital status
|
|
|
|
|
Single
|
Ref
|
|
|
|
Currently married
|
0.855 (0.47-1.57)
|
0.612
|
|
|
Other
|
2.16(0.69-6.79)
|
0.186
|
|
|
Time at local residence
|
|
|
|
|
Less than 6 months
|
Ref
|
|
|
|
More than 6 months
|
1.52 (0.73-3.17)
|
0.258
|
|
|
Education level
|
|
|
|
|
Middle school or less
|
Ref
|
|
|
|
Senior school
|
1.81 (0.57-5.69)
|
0.313
|
|
|
Secondary school or junior college
|
1.56 (0.54-4.49)
|
0.409
|
|
|
Bachelor’s degree or higher
|
2.34 (0.87-6.32)
|
0.093
|
|
|
Sexual orientation
|
|
|
|
|
Heterosexual
|
1.90 (0.45-8.06)
|
0.377
|
|
|
MSM
|
Ref
|
|
|
|
Condom use in Past 6m
|
|
|
|
|
Always
|
Ref
|
|
|
|
Not always
|
6.50 (1.11-8.66)
|
0.035
|
|
|
Sexual partner in Past 6m
|
|
|
|
|
0-1
|
Ref
|
|
|
|
2~3
|
1.31 (0.71-2.42)
|
0.393
|
|
|
>3
|
1.74 (0.63-4.83)
|
0.284
|
|
|
Clinical symptoms
|
|
|
|
|
No
|
Ref
|
|
Ref
|
|
Yes
|
2.52 (2.03-3.13)
|
0.001
|
2.52 (2.03-3.13)
|
0.001
|