د. حامد الزعبي Spirochaetes
Treponema (T. pallidum) (T. pertenue) (T.endemicum) (T. carateum) orher non pathogenic spp
T. pallidum Syphilis: Belongs to spirochetes which are thin walled, flexible spiral rods Motile by flagella: at both sides wrap around the bacterial cell body. In contrast to other motile bacteria, these flagella do not protrude into the surrounding medium but are enclosed within the bacterial outer membrane Has not been grown on bacteriologic media
Syphilis Transmission: 1. Sexually 2. Contact with skin lesions 3. Congenital (mother to baby) 4. Blood donation during primary and secondary stages
Syphilis Pathogenesis: No toxins Multiplication at primary site of infection leading to a painless ulcer called Chancre Widespread via blood to many tissues Primary, secondary, latent, late tertiary stages Human only Infectious dose less than 10 organisms
Incubation period: 2-10 weeks, 3 wks usually Early (primary and secondary), latent and tertiary stages Overall and of the early diseases: 1/3 will heal without treatment 1/3 will go into latent 1/3 into tertiary
Syphilis / clinically 1. Primary: Painless Chancre on genitalia, cervix or anogenital area Usually single Disappear spontaneously in 3 6 weeks Infectious Inguinal LNE Exudates used for diagnosis
2. Secondary syphilis (infectious): 2-12 weeks after chancre disappeared Non specific symptoms (e.g fever malaise, lethargy, headache, lymph nodeenlargement) Maculopapular and pustular rash mainly on trunk and extremities Heals spontaneously There might be Multiplication and production of lesion in lymph nodes, liver, joints, muscles, skin and mucous membranes
3. Latent: No lesion but serological evidence exists Early and late latent Early latent phase: may reactivate and manifest as a secondary lesion i.e infectious 4. Tertiary (3-30 years): Neurosyphilis: e.g Meningoencephalitis and paralysis Cardiovascular: aneurysm of ascending aorta, aortitis Skin and bone granulomatous lesions (Gummas)
Congenital syphilis: Blood placenta fetus Intrauterine death, abortion, low birth weight Facial abnormalities e.g saddle shape nose Diagnosis: 1. Detection of the organism in the exudates and lesions using dark field E.M or phase contrast, Immunofluorescent antibodies Low sensitivity
2. Serology: A. Non-specific antibodies (1-2 weeks after the primary chancre appears): Rapid plasma regain test (VDRL test): detecting anticardiolipin antibodies Cardiolipin? B. Specific antibody detection: These tests should be used to confirm that a positive result with a non-specific test is truly due to syphilis.
Syphilis / serology specific antibody detection 1. FTA-Abs (fluorescent Treponema antibodies-absorption): patient's serum is first absorbed with non-pathogenic treponemes to remove cross-reacting antibodies before reaction with T. pallidum antigens 2. TPHA (Treponema pallidum Haemagglutinin antibodies)
Treatment: Penicillin G If allergic, Doxycycline or erythromycin is a good alternative In neurosyphilis use penicillin and Doxycycline together Prevention: No vaccine Early diagnosis and treatment of case and contact is important Sexually transmitted: Test for syphilis if any STD exists
Borrelia Burgdorferi: Lyme Disease.. Common USA, Biting Insects (Ticks).. Wild Animals, Rodents, Birds..Incub. Few Weeks- Months..Single/Multiple Skin Lesions.. Systemic Disease.. Arthritis, CNS.. Cardic Abnormalities.. B. recurrentis: recurrent fever, can be fatal Liptospiral diseases: Zoonosis, mild-severe fatal systemic.. Weils s disease..high Fever, Jaundice, vasculitis, Bleeding. Diagnosis: Serological Tests, Special culture
Chlamydia
Family: Chlamydiaceae Genus: Chlamydia C. trachomatis - Urogenital infections, trachoma, conjunctivitis, pneumonia and lymphogranuloma venerium (LGV) Genus: Chlamydophilia C. psittaci - Pneumonia (psittacosis) C. pneumoniae - Bronchitis, sinusitis, pneumonia and possibly atherosclerosis
Chlamydia- Microbiology Small obligate intracellular parasites Inner and outer membrane LPS but no peptidoglycan Cell wall not well characterized Energy parasites Can t make ATP
Physiology and Structure Elementary bodies (EB) Extracellular form Rigid outer membrane Disulfide linked proteins Resistant to harsh conditions Non-replicating, non-metabolically active form Infectious form Bind to columnar epithelial cells (macrophages)
Physiology and Structure Reticulate bodies (RB) Intracellular form Fragile membrane Fewer disulfide bonds Metabolically active form Replicating form Non-infectious
Developmental Cycle of Chlamydia EB bind to host cells Epithelial Macrophage Internalization Endocytosis Phagocytosis Inhibition of phagosomelysosome fusion Reorganization into RB Breakdown of disulfide bonds Growth of RB
Chlamydia trachomatis Trachoma Inclusion conjunctivitis Infant pneumonia Ocular lymphogranuloma venerium Urogenital infections Lymphogranuloma venerium
C. trachomatis Ocular infections Worldwide Poverty and overcrowding Endemic in Africa, Middle East, India, SE Asia United States - American Indians Infection of children Transmission: droplets, hands, contaminated clothing, flies, contaminated birth canal
Clinical Syndrome -Trachoma From: G. Wistreich, Microbiology Perspectives, Prentice Hall
Clinical Syndrome -Trachoma (C.trachomatis biovar: trachoma) Chronic or repeated infection Follicle formation on conjunctiva Scarring of the conjunctiva
Eyelids turn in and abrade cornea Ulceration Scarring Blood vessel formation
Flow of tears impeded Secondary infections
C. trachomatis - Diagnosis Histo Cytology: Iodine-staining inclusions Not sensitive Culture: Iodine staining inclusions Most specific Iodine-stained inclusion bodies
C. trachomatis - Diagnosis Antigen detection (ELISA or IF) Group specific LPS Strain specific outer membrane proteins Serology Can t distinguish between current or past infection Detection of high titer IgM antibodies can be helpful Nucleic acid probes Several kits available May eventually replace culture
C. trachomatis - Treatment and Prevention Tetracycline, erythromycin and sulfonamides Vaccines are of little value Treatment coupled with improved sanitation Safe sexual practices Treatment of patients and their sexual partners
Chlamydophilia (Chlamydia) psittaci Psittacosis (Parrot fever) Ornithosis
Pathogenesis - C. psittaci Inhalation of organisms in bird droppings Person to person transmission is rare Hematogenous spread to spleen and liver Local necrosis of tissue Hematogenous spread to lungs and other organs Lymphocytic inflammatory response Edema, infiltration of macrophages, necrosis and occasionally hemorrhage Mucus plugs may develop in alveoli Cyanosis and anoxia
Laboratory Diagnosis - C. psittaci Serology Fourfold rise in titer Treatment: Tetracycline or erythromycin Quarantine of imported birds Control of bird infection Antibiotic supplementation of food
Chlamydophilia (Chlamydia) pneumoniae Person to person spread Respiratory droplets Atypical pneumonia Atherosclerosis? Diagnosis: Serology Treatment: Tetracycline or erythromycin
The End