Question

Genmus Chlanydio See GOD. Relevant species, if applicable: Morphological Characteristics Gram stain results Additional: Habitat/Reservoir: Virulence Factors: Diseases/Symptoms: Lab ID/Control& Treatment: Unique Features or Clinical Manifestations:

Answer 1

Genus: Chlamydia spp.

Relavant species:trachomatis

Gram stain:gram negative

Other characters:

Gram-negative cocci.  Non-motile.  Obligate, aerobic intracellular parasite that only infects humans .  C. trachomatis also causes a form of blindness known as trachoma, but the sexually transmitted disease causes Chlamydia urethritis in men and cervicitis in women. It is transmitted through infected secretions, and mainly infects mucosal membranes, particularly the cervix, rectum and urethra. The name comes from the Greek word “chlamys” which basically means “cloak-like.” This is a reference to the way the intracytoplasmic inclusions caused by the bacterium are draped around the nuclei of infected host cells.  Generally parasitizes epithelial cells. The clinical features, pathogenesis, pathology and epidemiology of C. trachomatis are similar to those of viral infections.  These similarities to other pathogens are the reason that Chlamydia wasn’t recognized as a sexually transmitted disease until around 1960.

            Chlamydia has a very unique life-cycle, alternating between an infectious elementary body, and a replicating, non-infectious reticulate body. The elementary body is the dispersal form of the pathogen, much like a spore. The bacterium induces its own endocytosis upon exposure to host cells. Once inside a cell the elementary body germinates as the result of interaction with glycogen, and converts to its vegetative, reticulate form. The reticulate form divides every 2-3 hours through binary fission, and has an incubation period of about 7-21 days in its host. Since it has no cell wall, it is detected as an inclusion in the cell. After division, the pathogen reverts back to its elementary form and is released by the cell through exocytosis.

Reservoir /Habitat :Infected sexually active adults and adolescents.

Virulence factors:  Chlamydia trachomatis begin colonization using sialic acid receptors as binding sites in epithelial cells of the genitalia. Apparently, these sites are not accessible to phagocytes, T-cells, or B-cells. The pathogen also exists as 15 different serotypes, although only two of them (D and K) cause the sexually transmitted disease . C. trachomatis has a unique cell wall structure which enables it to inhibit phagolysosome fusion within phagocytes. The bacterium is Gram-negative due to an outer lipopolysaccharide membrane, but lacks peptidoglycan in its cell wall.

            It has recently been discovered that Chlamydia has a small needle-like projection called a type III secretion apparatus. It serves as a conduit form the bacteria to the cytoplasm of the host cell. This means that Chlamydia can inject proteins directly into the cytoplasm of the cell and avoid lysosomes. Scientists have also seen the Chlamydia-infested vacuole divert lipids to itself rather than to another compartment of the host cell.

Disease/symptoms:

Symptoms in women include vaginal discharge, irritation of the pubic area, burning during urination, lower abdominal pain, painful intercourse, and vaginal bleeding. Men’s symptoms usually include a clear, white, or yellow discharge from the urethra, burning sensation during urination, tenderness or pain in the testicles, and tingling or itching around the tip of the urethra. If symptoms do occur, they usually appear within 1 to 3 weeks after exposure.

            What makes Chlamydia particularly dangerous is that around 75% of women and 50% of men who are infected are asymptomatic, thus are unaware that they are infected. Prolonged exposure to the pathogen leads to infertility in both men and women. Infection also subjects women to pelvic inflammatory disease as well as ectopic pregnancy. Research has shown that women infected with Chlamydia have an increased risk for cervical cancer and HIV transmission. In men, infections often begin in the urethra, with urethritis, and can progress to the upper genital tract, causing epididymitis and prostatitis. The bacterium can also attach to sperm, which decreases the sperms viability and motility, in turn reducing fertility. This attachment to the sperm also increases the chances of transmission to women.

Control/treatment:Chlamydia is easily treated and cured with antibiotics. A single dose of azithromycin or a week of doxycycline are the most commonly prescribed treatments (CDC). Treatment is essential for preventing serious health consequences and to prevent further spreading of the disease. It is vital that all sexual partners are tested and treated as well. Screening is one of the most effective, yet underutilized, tools for preventing the further spread of STDs.

            Chlamydia can be prevented by abstinence from sexual contact or a monogamous relationship with an uninfected partner who has been tested. Latex condoms can also greatly reduce the risk of infection