Chlamydia. By Madhuri Reddy

Transcription

1 Chlamydia By Madhuri Reddy Disease- Chlamydia Etiologic agent Chlamydial infection is caused by the genera Chlamydia, of which the type of species is Chlamydia trachomatis. This infection can causes diseases in many of the internal organ systems. C. trachomatis most commonly infects the cervix, urethra, uterus, nasopharynx and epididymis.(1) Transmission Chlamydia is transmitted through sexual contact or perinatally. Sexual contact transmission of chlamydia occurs with vagina, mouth, penis or anus of an infected sexual partner. (2) Chlamydia can be acquired from an untreated mother to her baby during childbirth. The exposure to chlamydia can result in ophthalmia neonatorum or pneumonia in some infants. (2) Reservoir Chlamydia trachomatis can not produce ATP on its own and requires it from the host. C. trachomatis usual reservoirs of the human body are the mucous membrane of the genital region, throat, and eyes. (3) General characteristics Chlamydiae are small gram- negative obligate intracellular microorganisms that only infect the squamocolumnar epithelial cells. (1) C. trachomatis has a unique life cycle; it is a dimorphic bacterium with a two-phase life cycle. It can survive as an elementary body and a reticulate body. The elementary body is smaller; it attaches and enters the host cell, this is the dispersal form, which is comparable to a spore.(4) The dispersal form is 0.3um and upon exposure to the target cell it induces its own endocytosis. (4) This makes it more dangerous of the two. Reticulate body is larger, and promotes metabolic activities and reproduce through binary fission, approximately 2-3 hours per generation. (4) It contains no cell wall and has an incubation period of 7-21 days in the host. After division, the body denatures back to the elementary form and is then released by exocytosis. (4) Key tests for identification Chlamydia often does not present any symptoms, therefore it can go undetected. To identify bacterium C. trachomatis is by isolating its culture. Antigen detection is the most cost and time efficient test. These methods include direct fluorescence antibody assays and enzyme

2 immunoassays. (5) Other test include nucleic acid amplification techniques, which is based on polymerase chain reactions, ligase chain reaction, and transcription- mediated amplification technology, that are associated with urine samples. (5) It is a less invasive method than obtaining culture from a genital swab. Signs and symptoms Early stages of Chlamydia trachomatis often goes undetected. Signs and symptoms start to occur after one to two weeks after exposure to chlamydia. (6) Mild symptoms include painful urination, lower abdominal pain, discharge, painful intercourse, bleeding between period and after sex in women, and testicular pain in men. (6) Symptoms of an infected rectum includes rectal pain, discharge and bleeding. (6) Historical information In 1907, Chlamydia trachomatis was discovered by Halberstädter and von Prowazek. They observed conjunctival scraping from and infected orangutan. (7) It was observed that the infectious agent and that inclusion were draped around the nucleus. This suggested the name Chlamydoza. Chlamy is greek for cloak. (7) Chlamydia was originally classified as a virus (5). However, in 1965 after further research with culture technique and electron microscopes the findings showed the presence of DNA, RNA, and ribosome which falsified the classification.(5) Virulence factors Chlamydia has a unique cell wall, it has LPS membrane but no peptidoglycan. It contains cysteine rich proteins which are function equivalent to peptidoglycan, which inhibits phagolysosome fusion. (8) Chlamydia releases an enzyme known as chlamydial proteasome/protease which causes the organisms to denature the host DNA. This allows it to evade the host immune system and hinders the activation of the genes response for the major histocompatibility complex. (8) Control/Treatment Chlamydia is curable with the right medication. Oral antibiotics are most commonly used, which include but not limited to azithromycin, doxycycline, and erythromycin. (9) People who acquire chlamydia should refrain from sex until full cycle of antibiotics is completed. This is because chlamydia can be transmitted to sexual partner during the treatment cycle causing an individual to transmit chlamydia to another and possible reinfection. (9) To prevent acquiring chlamydia individuals should get screened yearly, always wear a condom, and practice monogamy. (9) Prevention/ Vaccine

3 Currently there is not a vaccines available for patients. However, in a recent study, the Journal Vaccine recently published that the researchers show that a novel chlamydial antigen known as BD584 is a potential vaccine candidate for the most common species of chlamydia known as Chlamydia trachomatis.(10) In the research team's study, BD584 was able to reduce chlamydial shedding -- a symptom of C. trachomatis -- by 95 per cent. The antigen also decreased hydrosalpinx, another C. trachomatis symptom which involves fallopian tubes being blocked with serous fluids, by 87.5 per cent. (10) Local Cases According to Center for Disease Control and Prevention, in 2015, Chlamydia is one of the most common sexually transmitted diseases in the United States. In the U.S.A rates of reported cases of chlamydia were highest in the Southern region, cases per 100,000 population, followed by the Midwest, cases per 100,000. The western region reported cases per 100,000 and Northeast cases per 100,000. (1) Texas is ranked 10th among 50 states in chlamydial infections, which is per 100,000 persons. Reported rates of chlamydia among women are cases per 100,000, the number of cases in women was 3 times greater than those among men, which are 247 cases per 100,000. (11) Figure 1. Chlamydia- Rates of reported cases by Sex, United States Global cases or outbreaks According to World Health Organization, Chlamydia is the most common STD in the world. It is most prevalent in young and minority women. The estimated pooled prevalence for chlamydia in men globally was 2.7%, with regional values that ranged from 1.3% to 5.2% (12) An estimated

4 131 cases of Chlamydia in the world, the estimates for chlamydia was the highest in the Region of the Americas and Western Pacific Region. (12) In Figure 2, a total of 79 studies were identified, but only some provided information for all three infections. For the High Income North America region, the estimates were based on the United States national estimates. Figure 2- Number of data points that met the study inclusion criteria for WHO 2012 estimates by infection, region, and sex. Reference 1."Chlamydial Genitourinary Infections." Background, Pathophysiology, Etiology. Medscape, 07 Oct Web. 06 May "Chlamydia - CDC Fact Sheet (Detailed)." Centers for Disease Control and Prevention. Centers for Disease Control and Prevention, 17 Oct Web. 06 May "Chlamydia (genital Infection)." Health.vic, Web. 06 May "Chlamydia Trachomatis." Microbewiki, 29 Apr Web. 06 May 2016.

5 5.Peeling, Rosanna W. and Robert C. Brunham. "Chlamydiae as Pathogens: New Species and New Issues." Emerging Infectious Diseases Volume 2 OCT 1996 [ ]. 02 MAY 2007 < 6."Chlamydia Trachomatis." Mayo Clinic. Mayo Foundation for Medical Education and Research, 11 Apr Web. 06 May Budai, I. "Chlamydia Trachomatis: Milestones in Clinical and Microbiological Diagnostics in the Last Hundred Years: A Review." Acta Microbiologica Et Immunologica Hungarica.U.S. National Library of Medicine, Mar Web. 06 May Byrne, Gerald I. "Chlamydia Trachomatis strains and virulence: rethinking links to infection prevalence and disease severity." The Journal of Infectious Diseases. U.S. National Library of Medicine, 15 June Web. 06 May Gholipour, Bahar. "Chlamydia: Symptoms, Treatment and Prevention." LiveScience. Purch, 06 Oct Web. 06 May McMaster University. "First Widely Protective Vaccine against Chlamydia19." ScienceDaily. ScienceDaily, 19 July Web. 06 May Texas State Health Profile." Texas 2015 State Health Profile(n.d.): n. pag. Centers for Disease Control and Prevention, Web. 06 May "Sexually Transmitted Infections (STIs)." World Health Organization. World Health Organization, n.d. Web. 07 May 2017.