Be alert to these 4 common pathogens! Young people are more susceptible to infection

This article is from the article "Detection of Pathogens of Four Common Sexually Transmitted Diseases in Peking Union Medical College Hospital from 2013 to 2018" in Volume 12, Issue 4 of the 2021 issue of Peking Union Medical College Journal.

Original author: Du Juan, Zhang Dong, Zhang Rui, Chen Yu, Yi Jie, Wu Jie, Dou Yaling, Yang Zhuo, Ye Ali, Kong Lingjun, Gan Yong, Yang Qiwen*

Sexually transmitted diseases (STDs) refer to a type of disease that is transmitted through sexual contact. The STDs that my country focuses on preventing and treating mainly include syphilis, gonorrhea, AIDS, genital herpes, condyloma acuminatum, chancroid, non-gonococcal urethritis (NGU), and lymphogranuloma venereum.

Non-gonococcal urethritis is one of the most common sexually transmitted diseases in my country. Its common pathogens include Chlamydia trachomatis (CT), ureaplasma urealyticum (UU), Mycoplasma genitalium (MG), Trichomonas vaginalis, Candida albicans, herpes virus, etc.

Neisseria gonorrhoeae (NG) can cause purulent infection of the urogenital system (gonorrhea) and is also one of the common pathogens of sexually transmitted diseases.

In order to better assist clinical screening and control disease transmission, Professor Yang Qiwen's team from the Laboratory Department of Peking Union Medical College Hospital retrospectively collected 12,804 specimens submitted by patients with suspected sexually transmitted diseases from Peking Union Medical College Hospital from 2013 to 2018, and analyzed the detection of four common sexually transmitted disease pathogens, including Chlamydia trachomatis (CT), Ureaplasma urealyticum (UU), Mycoplasma genitalium (MG), and Neisseria gonorrhoeae (NG). The following results were obtained:

①12,804 specimens included urine samples, female cervical swabs, and male urethral swabs, of which 6,658 were from male patients and 6,146 were from female patients. The patients were aged 2 to 87 years old, of which 76.07% were aged 21 to 40 years old (Table 1).

②The positive rates of the four common pathogens were Ureaplasma urealyticum, Chlamydia trachomatis, Mycoplasma genitalium, and Neisseria gonorrhoeae from high to low.

Ureaplasma urealyticum has the highest positive detection rate, so who should take the blame? Ureaplasma urealyticum (UU) mainly resides in the human urogenital tract, so sexual contact is the main route of its transmission. Normal people can carry it without causing disease, and the detection rate in the reproductive tract of healthy women is ≤20%. However, when the human body's immunity is reduced and the number of sexual partners is large, it is a conditionally pathogenic microorganism that can often cause various adverse effects on the human body. UU infection can cause damage to the fallopian tube mucosa and induce fallopian tube inflammation; it can also cause inflammation of the cervix and vagina, and is related to infertility and adverse pregnancy outcomes.

What harm do the other three most common pathogens with the highest positive detection rates do to the human body? Chlamydia trachomatis (CT) is a strictly eukaryotic intracellular microorganism with multiple serotypes. CT infection can not only cause trachoma, but also lead to diseases such as urogenital tract infection and venereal lymphogranuloma. Pregnant women may have no obvious symptoms after being infected with CT, but it can lead to a variety of adverse pregnancy outcomes such as low birth weight and premature birth.

Mycoplasma genitalium (MG) was first isolated from urethral specimens of two male NGU patients in 1980. It is one of the common pathogens of male urogenital tract infection. Did you know? More and more evidence shows that infection with MG can cause female mucopurulent cervicitis, endometriosis, and ectopic pregnancy or infertility secondary to fallopian tube infection. Gonorrhea caused by NG infection is one of the common STDs. Urethritis, cervicitis, and salpingitis are the most common clinical manifestations. If not diagnosed and treated in time, it can also lead to infertility.

③ In cases of infection with pathogenic microorganisms of the reproductive tract, it is necessary to be vigilant about co-infection. The most common co-infections of the above four common pathogens are ureaplasma urealyticum + Chlamydia trachomatis (4.13%) and ureaplasma urealyticum + Mycoplasma genitalium (1.98%), and the highest incidence rate is in patients ≤20 years old.

Pathogen co-infection and age/sex distribution A. Ureaplasma urealyticum + Chlamydia trachomatis

Pathogen co-infection and age/sex distribution B. Ureaplasma urealyticum + Mycoplasma genitalium

Why are young people more susceptible to sexually transmitted disease pathogens? Studies have shown that whether it is a single infection or a combined infection (except for single infection of NG and UU in female patients), the positive rate of the four pathogens is the highest in people ≤20 years old, which is consistent with the data of the Centers for Disease Control and Prevention in the United States in 2011.

Why are young people more susceptible?

Some scholars analyzed that the reason is that people aged ≤20 have relatively weak awareness of sexual protection and may have immature cervix, making them more susceptible to infection by pathogens of sexually transmitted diseases.

However, there are also reports that cervical columnar epithelial ectopy is not an independent risk factor for sexually transmitted infections in adolescent women, and the exact conclusion of cervical immaturity and pathogen infection needs further verification. It is believed that the level of sIgA, a local protective antibody in the cervical mucus of adolescent women, is slightly lower than that of adult women, which may reduce its protective effect and facilitate pathogen infection.

In addition, adolescent female sexual organs are not yet fully mature, and their vaginal flora is different from that of adults, which may increase susceptibility to sexually transmitted diseases. Males aged ≤20 years may have frequent sexual contact during adolescence and lack awareness of sexual protection, which leads to an increased infection rate of various sexually transmitted pathogens.

Therefore, we are particularly reminded that we should attach great importance to the dissemination of knowledge related to sexually transmitted diseases among young people, enhance their self-protection awareness, and reduce the risk of infection with sexually transmitted diseases.

In addition, Professor Yang Qiwen's team from the Laboratory Department of Peking Union Medical College Hospital analyzed the detection of four common STD pathogens in the hospital from 2013 to 2018 and found that the number of samples sent for inspection showed an overall increasing trend year by year, which fully demonstrates the effectiveness of health education and the enhancement of residents' awareness of medical care. People have paid more and more attention to sexually transmitted diseases.

However, since most patients with urogenital tract infection have no clinical symptoms or have mild symptoms, they are often easily ignored. If not treated in time, it can cause serious complications of the reproductive tract, so it should not be taken lightly. In clinical practice, for patients with suspected sexually transmitted diseases, the cause should be identified as soon as possible, an accurate diagnosis should be made, and targeted treatment should be carried out. Especially for those who are persistent, the possibility of co-infection should be vigilant.

In short, only by responding scientifically, enhancing immunity, and focusing on early diagnosis and treatment can we stay away from sexually transmitted diseases.

Text Compilation: Liu Yang Layout Design: Zhao Na Review and Proofreading: Li Na, Li Yule, Dong Zhe Supervisor: Wu Wenming

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