Chlamydia trachomatis is an obligate intracellular parasite of which 18 serologically distinct variants exist (these have been categorized by identifying monoclonal antibodies). These serotypes are:

Chlamydia is spread by sexual contact (vaginal, anal, or oral sex) and as vertical transmission at birth from mothers to infants.

The higher the number of sexual partners is, the greater the risk of contracting the infection is.

Indeed, the principal risk factor for contracting Chlamydia is having had a new sexual partner in the last 6 months.

Any clinical symptoms appear 1–3 weeks after infection. In women, Chlamydia infects the cervix, and, in most cases, the urethra, causing vaginal discharge, coital bleeding, and dyspareunia. On physical examination, mucopurulent or purulent discharge from the endocervical canal and cervical friability are common (Fig. 14.1). In an elevated number of cases, the infection can involve the urethra and the symptoms are characterized by dysuria, bladder tenesmus, and urinary frequency. Infection can cause pelvic inflammatory disease with abdominal pain, fever, backache, intermenstrual bleeding, and possible persistent fallopian tube damage.

Men may act as disease carriers, spreading the condition, but rarely developing long-term health problems. Infection could be silent for months or years. In this case, the condition may be identified during a screening programme and/or routine testing. In men, chlamydia infection causes urethritis and epididymitis (from 30 to 50% of non-gonococcal urethritis is caused by chlamydia). The symptoms are dysuria and discharge when squeezing urethral meatus. If the infection is transmitted by anal sex, the symptoms are characterized by proctitis with pain and bleeding. If the transmission is by oral sex, the manifestation is a pharyngeal infection.

Despite the fact that symptoms are tolerable and are often not diagnosed, the consequences for the reproductive organs, and especially for women infected with Chlamydia, may be very serious. Untreated chlamydia infections put women at an increased risk (40–67%) of developing pelvic inflammatory disease. The involvement of the fallopian tubes, the uterus, and of other adjacent tissues can cause permanent damage (tubal occlusion being the worst possible consequence), or lead to peri-hepatitis (Fitz-Hugh-Curtis syndrome). Additional negative outcomes include chronic pelvic pain, tubaric infertility, and ectopic, or “extra-uterine”, pregnancy. Tropism from Chlamydia in the cylindrical epithelial cells of the endo-cervix causes an inflammatory reaction which attracts polymorphonucleated cells and consequently leads to the development of a humoral immune response. Replication of the micro-organism in the host leads to cellular lysis with associated tissue damage which is worsened by the immune response. Several studies demonstrated that tubal damage pathogenesis is prevalently caused by the host immune reactivity, and, in particular, by the prolonged production of cytokine and chemokine by the tubaric epithelium. Immune reaction reactivation, is also possible, however, in the case of persistent infection, or re-infection, which trigger fibrotic responses towards Chlamydia antigens, among which is the Hsp60 (CT-Hsp60) protein which shares common amino acid sequences with man and with other bacteria, such as Escherichia coli [7].

In men, permanent damage seems less probable, although Reiter’s syndrome has a higher incidence, which is a form of sero-negative arthritis that includes skin lesions, urethritis, and iridocyclitis.

Chlamydia infection may also increase susceptibility to HIV, which, in adolescents, has been shown to increase by a factor of 5. Moreover, a persistent Chlamydia infection can increase the risk of infection by oncogenic types of HPV, thus increasing the risk of cervical cancer [8, 9].

Urogenital infections caused by Chlamydia may be diagnosed using endocervical tampon samples (in women) and endo-urethral tampon sample (in men) or by testing “first emission” urine samples.

Nucleic acid amplification tests (NAATs) are the most sensitive tests and are recommended for detecting Chlamydia trachomatis infection [10].

NAATs can be performed on endocervical, urethral, vaginal, pharyngeal, rectal, or urine samples. The accuracy of NAATs on urine samples has been found to be nearly identical to that of samples obtained directly from the cervix or urethra [11].

Treating Chlamydia infections prevents adverse reproductive health complications and continued sexual transmission, and treating their sexual partners can prevent re-infection and infection of other partners.

A meta-analysis of 12 randomized clinical trials of azithromycin versus doxycycline for the treatment of urogenital chlamydial infection demonstrated that the treatments were equally efficacious, with microbial cure rates of 97% and 98%, respectively [12].

A high prevalence of Chlamydia trachomatis infection has been observed in previously treated patients. Most of these post-treatment case are not due to the inefficacy of the treatment, but rather, are usually caused by re-infection following unprotected sexual intercourse with, either, an inadequately treated partner, or with a new, partner who is also infected. For this reason is very important to treat the partner, or partners, whether or not they are asymptomatic, and, even, following a negative test. Complete abstention from sexual activity is recommended until 7 days after therapy with single-dose azithromycin or until after treatment with doxycycline has been completed. The use of barrier contraception (e.g. a condom) significantly reduces the risk of transmission but does not eliminate it completely. Given the wide diffusion of asymptomatic Chlamydia infections, an annual chlamydia screening programme would be opportune for sexually active women below the age of 25, as well as for all sexually active women with frequent new or multiple sexual partners, having a partner with a sexually transmitted infection, and for all pregnant women. In some European countries, the annual report of the National Chlamydia Screening Programme has registered a reduction in the episodes of pelvic inflammatory disease [13, 14].

It is a sexually transmitted infection caused by some serotypes of Chlamydia trachomatis (L₁L₂L_3,) which cause a chronic disease. It is endemic in Asia, Africa, and South America and was observed among male homosexuals in Europe (especially if infected HIV), where is a relatively common cause of proctitis [15–17].

The heterosexual transmission has been attributed to asymptomatic women carriers whereas in male homosexuals, the asymptomatic rectal infection is the likely source of transmission [18]. The contagion can only be contracted through vaginal, oral, and anal sexual intercourse. The infection is manifested by a vesicle in uro-genital or rectal region that may erode, with the formation of a small painless ulcer that heals in a week with no results, and that often goes unnoticed. In the next phase, for the spread of the bacterium in the lymphatic system, the typical symptoms are a unilateral lymphadenitis (potentially involving the iliac, perirectal, and inguinal lymph nodes) associated with fever, malaise, and arthralgia. If not treated in good time, the infection may complicate with peri-rectal abscesses, fistulas, and scars that requiring surgery.

It is an infection caused by Gram-negative bacillus Haemophilus ducreyi, rare in Europe, but particularly common in tropical countries, although the prevalence of chancroid appears to have decreased worldwide. Transmission occurs as a result of a trauma during sexual intercourse, and after an incubation period of about 3–10 days, the infection is manifested by the appearance of a papule with erythematous edge on the skin or on mucosal of the genitals. After about 24–28 h, the papule develops first in pustule and then in soft, bleeding, and painful ulcer. Clinically, an inguinal lymphoadenopathy and general symptoms may be associated. The combination of painful genital ulcer with inguinal adenopathy suppurative could be indicative of chancroid, especially after excluding other diseases responsible for genital ulcers (syphilis, herpes, lymphogranuloma venereum); the diagnosis can be confirmed by identifying the H. ducreyi even if the culture is difficult to perform [20].

As with other sexually transmitted infection leading ulcers in the genitals, the chancroid increases the risk of HIV transmission, and therapy in HIV-infected subjects is more complex.

Gonorrhoea is a sexually transmitted disease caused by infection with the Neisseria gonorrhoea bacterium. The incubation period varies from 3 to 10 days. N. gonorrhoea infects the mucous membranes of the reproductive tract, including the cervix, uterus, and fallopian tubes in women, and the urethra in women and men and can also infect the mucous membranes of the mouth, throat, eyes, and rectum. The organism adheres first to the epithelial cells, infects the epithelial layer, then penetrates into the sub-epithelial space, initiating the inflammatory process and its complications. Trans-luminal spread in males can lead to prostatitis orchiepididymitis and in females leads to PID (10–20% of the cases) and peritonitis. The bacterial dissemination can also cause bacteraemia, cutaneous lesions, fever, arthralgia, arthro-synovitis, especially of knee, hip, and wrist. Transmission can occur through sexual contact with the penis, vagina, mouth, or anus of an infected partner. Gonorrhoea can also be spread perinatally from mother to baby during childbirth. Highest reported rates of infection are among sexually active teenagers and young adults (15–29 years old). Gonorrhoea infection, in particular, is also concentrated in specific geographical locations and communities. Subgroups of MSM are at high risk of gonorrhoea infection.

Asymptomatic infection of the genital tract is very frequent in women, occurring in about 90% of cases, and does occur in males, but in only about 5% of cases.

Rectal and pharyngeal infections are generally asymptomatic.

In women, symptoms are generally correlated with endocervical and urethral infections and include an increase or a variation in the characteristics of vaginal secretions, intermenstrual spotting, dysuria, menorrhagia, dyspareunia, muco-purulent urethral or cervical discharge. Gonorrhoeal infection should be excluded proactively in young females presenting with lower abdominal pain, pain during uterus and adnexa mobilization and in women with a significant sexual history. Pelvic inflammatory disease is thought to affect one in five women who remain untreated for gonorrhoea. The gonococco bacterium can cause Bartholin’s abscesses and can lead to inflammation of the para-urethral glands. In males, gonorrhoea infection generally causes acute urethritis, displaying profuse mucopurulent urethral discharge, dysuria, and meato-urethral erythema [22, 23].

The diagnosis is based on the identification of N. gonorrhoea in genital, rectal, pharyngeal, and ocular secretions [10].

Culture testing is a cheap, specific diagnostic test which permits rapid identification of the bacteria and also permits testing for antibiotic susceptibility. The use of selective culture terrains with the addition of antibiotics is recommended. Culture testing is recommended for samples which have been taken from the endocervix, urethra, rectum, and pharynx, and samples should be taken according to the information contained in the sexual anamnesis of the girl. The sensibility of culture testing is elevated for samples taken from the genital area as long as collection, transport, and storage of the sample itself are appropriate.

Instant microscopic evaluation with Gram, or methylene blue has good sensitivity (>95%), and good specificity, as a rapid diagnostic test in symptomatic men with urethral secretions. Microscopy has poor sensitivity (<55%) in asymptomatic men and in identifying endocervical infections (<55%) or rectal infections (<40%). Microscopic evaluation cannot be recommended as a diagnostic test in these circumstances.

Nucleic acid amplification tests (NAATs) for the detection of Neisseria gonorrhoeae have a sensitivity >95% compared with microbiological culture although sensitivity varies from one type of NAAT to another. In the case of confirmation of diagnosis, or on failure of therapy, an antibiogram culture should be performed. NAAT can be used on endocervical swabs, vaginal swabs, urethral swabs, and urine samples. In women, NAAT sensitivity on urine is lower than that of NAAT performed on endocervical and vaginal swab. A single vaginal or endocervical specimen evaluated with NAAT has a sufficient sensibility (90%) when used as a screening test. Collection of urethral, urine, rectal, and pharyngeal specimens should be directed by the anamnesis and from the personal sexual habits.

Gonorrhoea treatment is complicated by the ability of Gonorrhoea to develop resistance to antimicrobials, and this causes grave limitations to the therapeutic approach [24, 25].

However, there is a geographical variability of the diffusion of the resistant types. For this reason, it is useful to consider different therapeutic options established by the national surveillance system.

Increasing bacterial resistance also extends to these antibiotics and makes it essential, whenever persistent symptomatology is encountered, to repeat microbiological culturing with antibiogram of the isolated strain.

The Centre for disease control recommended a possible dual therapy by the addition to Ceftriaxone of Azithromycin 1 g, orally, in a single dose. Recent sex partners (i.e., persons having sexual contact with the infected patient within the 60 days preceding onset of symptoms, or gonorrhoea diagnosis) should be referred for evaluation, testing, and for treatment.

The therapy must be extended to any partners with the strong recommendation to abstain from any sexual activity until the therapy has been completed and the symptoms have disappeared.

It is a complex sexually transmitted infection caused by the bacterium Treponema pallidum.

It develops in several stages, each characterized by different symptoms and course and is considered a chronic systemic disease marked by alternating active phases and periods of latency.

According to data provided by the WHO, there is an increased prevalence of syphilis in the general population, and men are affected more than women.

Transmission is by sexual contact or by vertical, mainly transplacental (congenital syphilis).