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Transcript
ZaidKhalid MBBS220 Mycoplasma, Ureaplasma and Chlamydia Mycoplasma General characteristics 1. Small free-living bacteria 2. Highly pleomorphic 3. Doesn’t have cell wall a. Bounded by a triple layered unit membrane that contains sterols 4. Can pass thru 0,.45um filter a. Once thought to be virus 5. Grow slowly, generation time 1 – 6 hours 6. Formed small colonies; fired egg like appearance 7. Resistant to cell wall disrupting antibiotics a. Penicillin b. Cephalosporins 8. Have affinity to mammalian cell membranes 9. Important species a. M pneumoniae b. M hominis c. M genitalium Clinical Diseases Mycoplasma pneumoniae 1. Strict human pathogen 2. Transmitted thru infected respiratory secretions 3. Initiated by attachment to tip of a receptor on the surface of respiratory epithelial cells a. Attachment by specific adhesion protein 4. During infection, bacteria remains extracellular Mycoplasma hominis 1. Associated by various diseases 2. Can be cultured from upper urinary tract a. 10% of patients with pyelonephritis 3. Strongly associated with infection of pelvic inflammatory disease 5. Causing a. URTI i. Low grade fever ii. Malaise iii. Headache iv. Dry, non-productive cough v. Develop 2-3 weeks after exposure b. LRTI i. Tracheobronchitis ii. Atypical pneumonia a. Uterine tubes b. Tubo-ovarian abscesses 4. Has been isolated form blood of pts with a. Post abortal b. Post-partum fever Mycoplasma genitalium 1. One of the causes of non-gonococcal urethritis Pathogenicity Virulence factors 1. Possesses adhesion protein P1 a. Bind to the base cilia of epithelial cells b. Lead to eventual loss of ciliated epithelial cells c. Acts as superantigen i. Stimulates the migration of inflammatory cells ii. Release of cytokines Treatment DOC 1. Erythromycin 2. Doxycycline 3. Tetracycline All are effective in combating mycoplasma Though tetracycline reserved for only adults ZaidKhalid MBBS220 Ureaplasma General characteristics 1. Colonies are extremely small a. Formerly called the T strains for tiny colonies 2. Requires 10% of urea for growth 3. Important species a. Ureaplasma urealyticum 4. Can be distinguished from mycoplasma thru production of urease 5. Cultured in liquid media of urea and phenol red a. Growth of bacteria resulting in the release of ammonia from urea i. Increase in pH ii. Change in colour as indicator Clinical Diseases Ureaplasma urealyticum 1. Common in female genital tract 2. Associated with lung disease a. In premature low-birth weight infants b. Acquired the organism during birth 3. One of the causes of non-gonococcal urethritis in men Treatment DOC 1. Erythromycin a. U urealyticum is resistant towards tetracycline ZaidKhalid MBBS220 Chlamydiaceae General characteristics 1. Consists of 2 genera a. Chlamydia i. Chlamydia trachomatis 1. Grows in cell culture a. HeLA-229 b. McCoy c. BHK21 2. Subdivided into 2 biovars a. Biovar trachoma i. 15 serovars b. Biovar LGV i. 4 serovars c. Serovars i. A,B,Ba,C 1. Primarily conjunctiva ii. D-K 1. Primarily urogenital tract iii. L1-13 1. Inguinal lymph nodes b. Chlamydophila i. Chlamydophila psittaci ii. Chalmydophila pneumoniae 2. Once regarded as virus cause a. Can pass thru 0.45um filters b. Obligate intracellular parasites 3. Exist in two morphologically distinct forms a. Infectious elementary body b. Larger non-infectious reticulate body ZaidKhalid MBBS220 Clinical Diseases Chlamydia trachomatis 1. Trachoma a. Chronic disease caused by serovars i. A ii. B iii. Ba iv. C b. Presents with conjunctivitis with diffuse inflammation c. Involves the i. Entire conjunctiva ii. Corneal ulceration iii. Scarring iv. Pannus formation (invasion of blood vessels into the cornea 2. Adult inclusion conjunctivitis a. Acute follicular conjunctivitis associated by genital infections i. A ii. B iii. Ba iv. D-K b. Characterised by i. Mucopurulent discharge ii. Keratitis iii. Corneal infiltrates 3. Neonatal conjunctivitis i. Cervicitis ii. Endometritis iii. Urethritis iv. Salphingitis v. Bartholinitis vi. Perihepatitis c. Genital infection in men is symptomatic i. Present with urethritis d. Reiter’s syndrome i. Characterised by 1. Urethritis 2. Conjunctivitis 3. Polyarthritis 4. Mucocutaneous lesions ii. Believed to be initiated by genital infections 7. Lymphogranuloma venereum a. b. i. ii. iii. iv. a. b. Exposure to the bacteria at birth Characterised by i. Swelling ii. Hyperemia of the eyelids iii. Copious purulent discharge (many discharge) v. 4. Infant pneumonia a. b. Onset within 2-3 weeks after birth Rhinitis observed followed by a distinctive staccato cough vi. 5. Ocular lymphogranuloma venereum a. i. LGV serotypes have been implicated in Parinaud’s oculoglandular conjunctivitis Conjunctival inflammation associated with 1. Preauricular 2. Submandibular 3. Cervical lymphadenopathy 6. Urogenital infections a. b. In women is asymptomatic Symptomatic cases may present with c. d. i. ii. Sexually transmitted infection serovar L1-3 Characterised by Transient genital lesion Followed by multiocular suppurative involvement of the inquinal lymph node Nodes initially discrete but progress to 1. Matted 2. Suppurative (bubos) Skin over the node may be 1. Thinned 2. Multiple draining fistulas Systemic symptoms of 1. Fever 2. Chills 3. Headache 4. Arthralgia 5. Myalgia Late complication include 1. Urethral or rectal strictures 2. Perirectal abscesses 3. Fistulas Primary genital lesion is usually Small painless ulcer/papule Heals within few days, may be unnoticed Most common complaint is lymphadenopathy ZaidKhalid MBBS220 Clinical Diseases Chlamydophila psittaci 1. Causes human psittacosis (ornithosis) a. Zoonosis contracted thru inhalation of i. Respiratory secretion ii. Dust from the droppings of infected birds 2. Causes an acute infection of lower respiratory tract, presenting the onset of a. Fever b. Headache c. Malaise d. Muscle aches e. Dry hacking f. Cough g. Bilateral interstitial pneumonia 3. Occasionally develop into systemic complications a. Myocarditis b. Encephalitis c. Hepatitis Chlamydophila pneumoniae 1. Spread thru respiration droplets 2. Not like psittacosis, birds are not the reservoir 3. Most infections present with a. Pharyngitis b. Lower respiratory disease c. Or both 4. Clinical spectrum is the same with M pneumoniae infection 5. Pharyngitis/laryngitis may occur within 1-3 weeks prior to bronchitis/pneumonia a. Cough persists for weeks ZaidKhalid MBBS220 Cell Wall Defective Bacteria Protoplasts and Spheroplasts 1. Removal of bacterial cell wall can be accomplished by a. Hydrolysis with lysozyme b. Blockage of peptidoglycan biosynthesis with antibiotic 2. In osmotically protective media, it will generate a. Protoplasts from gram positive cells b. Spheroplasts from gram negative cells 3. Spheroplasts a. Retained outer membrane b. Entrapped the peptidoglycan L-phase variants (L forms ) 1. Cell wall defective microbial forms that can replicate serially on solid media as a. Non rigid cells b. Produce colonies 2. L forms a. Some are stable b. Others are i. Unstable ii. Revert top bacterial parental forms 3. Factor determines the revert 4. 5. 6. 7. a. Presence of residual peptidoglycan b. Acts as primers in its own biosynthesis Not genetically related to Mycoplasma Result from direct mutation or effects of antibiotic a. This may produce chronic infections b. The organism remains sequestered in protective regions of the body Some L forms are resistant to antibiotic a. Develop difficulty in chemotherapy Their reversion into bacillary form can produce relapses of the overt infection