Lecture 6 Chlamydia Ureaplasma Gardnerella

Urogenital System Microbiology… Lecture 6 Chlamydia Ureaplasma Gardnerella 1 _ First: Chlamydia: Three important species: Chlamydia trachomatis (considered here) Chlamydophila pneumoniae Chlamydophila psittaci _Chlamydia trachomatis I. General features: - Obligate intracellular bacterium, can’t live outside the cell - Lack peptidoglycan in the cell wall, so we can’t use antibiotics that attack cell wall - Gram negative Round cells - Has Major Outer Membrane Protein (MOMP) - Biovars: more subdivision, according to its pathogenicity: 1. A- C: Infect ocular epithelium (trachoma), may cause blindness! 2. D- K: Target UG epithelium (Non-gono-coccal urethritis “NGU”, mucopurulent cervicitis, proctitis (inflammation of the rectum), & inclusion conjunctivitis), may lead to iinfertility 3. L1- L3: Infect genital & colorectal regions (Lymphogranuloma Venereum “LGV”). II. Replicative cycle - Elementary body (EB): Small hardy forms: 1. Inert (needs an event to enter the Cycle) 2. Cycle starts by EB attachment to host cell plasma membrane, then Endocytosis, after that RB stage - Reticulate body (RB): Larger fragile intracellular replicative form 1. After EB entered the cell, it will be condensed, then multiply, finally Exocytosis occurs. 2 III. Epidemiology: - Prevalence in USA 5% generally & 20% among patients attending sexually transmetted diseases Clinics. - 1/3 of men with sexual contacts with infected females (cervicitis in females) develop Urethritis (in men). - I.P. = 2 – 6 weeks - Symptoms: Absent to mild IV. Pathogenesis: - Tropism to columnar epithelium of GUT, rectum and conjunctiva, besides other cells - Attachment via MOMP - In LGV enters via breaks in skin and mucus membrane, so it’s common in homosexuals - Tissue injury by proinflammatory cytokines and IL-8 released by infected epithelial cells - Chlamydial LPS also leads to cellular infiltration. - Macrophages & lymphocytes may aggregate at the submucosa leading to necrosis/scaring - Later stages: Immunological response to chlamydial Ags, V. Immunity: - Long time to develop; then is incomplete - 50% infected women shed organism 1 Y later - It’s an intracellular microorganism, so attacked by T cells (cell mediated immunity).. TH1 most protective; TH2 directed to MOMP; Antibodies cause injury in chronic cases VI. Clinical diseases, Genital infection manifestations: - Urogenital (D – K biovars of C. trachomatis): 1. In men: Urethritis, and epididymitis 2. In women: Cervicitis, salpingitis and urethral syndrome and complicated by PID (pelvic inflammatory disease), and infertility. - LGV (L1 – L3 biovars of C. trachomatis) 1. It is a Chronic infection of lymphatics and L.N - Those manifestations include: 1. Urethritis: Dysuria, with thin discharge 2. Cervicitis: Vaginal discharge (but commonly asymptomatic) 3. Pelvic Inflammatory Disease (PID): In 5-30%. It is an infection of the uterus, fallopian tubes (salpingitis) ovaries and inside of the pelvis. 4. Scaring: Chronic & repeated infections lead to sterility and ectopic pregnancy( when fallopian tube is blocked by scars) 3 5. Lymphogranuloma venereum (LGV): • Transient genital lesions • Multilocular suppuration of inguinal L.N. • Primary lesion: Small painless ulcer/papule (for few days and heal; unnoticed) • Systemic manifestations: fever, loss of appetite..etc • Complications: Urethral/Rectal strictures), perirectal abscesses and fistula • common in MSM (homosexual men): Hemorrhagic ulcerative proctitis • L.N. aspiration prevents rupture, (If it ruptures, serious complications may occur) VII. Diagnosis - Chlamydia detection: Smear or culture 1. Specimen: Urethra, Cervix epithelial cells 2. Culture: Inclusion bodies detected by IF, Culture incubation time: 3-7 days - DFA and Immunoassay methods - NAA tests (replace other tests; > SS & > SP) - LGV: Complement Fixation Antibody titer: Positive (the tiger is >1/32 in 80% - 90% of cases) shortly after inguinal lesions VIII. Treatment - Tetracyclines, Macrolides, Fluoroquinolones: 1. Azithromycin: First line therapy; single oral dose for non-LGV infection 2. Doxycycline: First line therapy for LGV 3. Erythromycin and Fluoroquinolones are alternatives - Prevention 1. Infected pregnant: Erythromycin (late months), To prevent transmission of bacteria to the newborn during ddelivery 2. General hygiene 4 _Second: Ureaplasma: I. General features: - - II. Related to Mycoplasma: 1. Both are Mollicutes (Prokaryotes,lacking cell wall) 2. Bound by Trilaminar membrane containing sterols which is acquired (vs other bacteria) 3. Family of both is Mycoplasmataceae” Sexually transmitted; high frequency of asymptomatic cases: Urethritis, Cervicitis, PID Very small, highly plastic, pleomorphic appear as coccoid bodies, filaments and bottle-shaped Do not stain or poorly; derived from G+ bacteria Urease positive (vs Mycoplasma) to differentiate Small dsDNA genome Species: 1. Urealyticum (T- Mycoplasma), T = Tiny 2. U. partum Treatment - Macrolides (Azithromycin, Clarithromycin,erythromycin) Tetracycline Fluoroquinolones (Alternatives) _ Third: Gardnerella I. General features: - Gram-variable, small, non-motile coccobacilli - It has G+ bacterial cell wall which is very thin (origin) - It is a facultative anaerobic bacterium - Important species: G. vaginalis - Sexual transmission 5 II. Clinical diseases: - Associated with bacterial vaginosis with other anaerobic bacteria, but does not cause it (i.e. is involved in it) not the causative agent, but help the causative - Manifested with vaginal discharge and fishy-odor when you add 10% KOH (Amine Whiff test ) - Associated with “Clue” cells = Epithelial cells covered with bacteria - Produces pore-forming toxin (vaginolysin) and other enzymes such as proteases III. Treatment: - Metronidazole and Clindamycin: Oral or Vaginal gel/cream _past years’ questions: The different between elementary and reticul: Sensitive and resistance to antibiotics 6