- Mycoplasma and Ureaplasma. - Rickettsia

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1 - Mycoplasma and Ureaplasma - Rickettsia

2 Mycoplasma and Ureaplasma

3 Family: Mycoplasmataceae Genus: Mycoplasma Species: M. pneumoniae Species: M. hominis Species: M. genitalium Genus: Ureaplasma Species: U. urealyticum

Morphology and Physiology Smallest free-living bacteria (0.2-0.8 µm) Require complex media for growth, PPL4. Facultative anaerobes Except M.

4 Morphology and Physiology Smallest free-living bacteria ( µm) Require complex media for growth, PPL4. Facultative anaerobes Except M. pneumoniae - strict aerobe Lack a cell wall? Part of Normal flora Cytoplasmic and cell membrane rich in cholesterol and GLYCOLIPIDS P1 antigen? Binds to RBCs I antigen Fried egg colonies

5 Fried Egg Colonies of Mycoplasmas

6 Adherence Pathogenesis - Mycoplasma P1 pili (M. pneumoniae) Movement of cilia ceases Clearance mechanism stops resulting in cough glycolipids Glycolipids: Brain cells cross antigenicity

7 Diseases Caused by Mycoplasma Organism Disease M. pneumoniae Upper respiratory tract disease, tracheobronchitis, atypical pneumonia, (chronic asthma??) M. hominis Pyleonephritis, pelvic inflammatory disease, postpartum fever M. genitalium Nongonococcal urethritis U. urealyticum Nongonococcal urethritis, (pneumonia and chronic lung disease in premature infants??) N.B. Other organisms infect humans but their disease association is not known.

8 Mycoplasma pneumoniae Tracheobronchitis Atypical pneumonia (walking pneumonia)

9 Epidemiology - M. pneumoniae Occurs worldwide No seasonal variation Proportionally higher in summer and fall

10 Clinical Syndrome - M. pneumoniae Incubation weeks Fever, headache and malaise Persistent non-productive cough Respiratory symptoms Radiological signs precede symptoms Slow resolution Rarely fatal

11 Laboratory Diagnosis - M. pneumoniae Microscopy Difficult to stain Can help eliminate other organisms Culture (definitive diagnosis) May take 2-3 weeks Serology PCR

12 Treatment Treatment and Prevention M. pneumoniae Tetracycline or erythromycin Newer fluoroquinolones Can t use cell wall synthesis inhibitors Prevention Avoid close contact No vaccine

13 Rickettsia and Orientia

14 Small obligate intracellular parasites Once considered to be viruses Gram-negative bacteria Stain poorly with Gram stain (Giemsa) Reservoirs - animals, insects and humans Arthropod vectors

15 Disease Organism Vector Reservoir Rocky Mountain R. rickettsii Tick Ticks, rodents spotted fever Scrub typhus O. tsutsugamushi Mite Mites, rodents Epidemic typhus R. prowazekii Louse Humans, squirrel fleas, Murine typhus R. thypi Flea Rodents

16 Rickettsia and Orientia N.B. Orientia was formerly Rickettsia

17 Replication of Rickettsia and Orientia Infect endothelial in small blood vessels - Induced phagocytosis Lysis of phagosome and entry into cytoplasm - Phospholipase Replication Release

18 Spotted Fever Group

19 spotted fever Rickettsia rickettsii Fluorescent Ab staining قراد Vector Tick

20 Clinical Syndrome - Rocky Mountain Spotted Fever Incubation period - 2 to 12 days Abrupt onset fever, chills, headache and myalgia Rash appears 2-3 days later in most (90%) patients Begins on hands and feet and spreads to trunk (centripetal spread) Palms and soles common Maculopapular but can become petechial or hemorrhagic

21 Rash of Rocky Mountain Spotted Fever

22 Clinical Syndrome - Rocky Mountain Spotted Fever Incubation period - 2 to 12 days Abrupt onset fever, chills headache and myalgia Rash appears 2-3 days later in most (90%) patients Begins on hands and feet and spreads to trunk (centripetal spread) Palms and soles common Maculopapular but can become petechial or hemorrhagic Complications from widespread vasculitis Gastrointestinal, respiratory, seizures, coma, renal failure Most common when rash does not appear Mortality in untreated cases - 20%

23 Laboratory Diagnosis - R. rickettsii Initial diagnosis - clinical grounds Fluorescent Ab test for Ag in punch biopsy - reference labs PCR based tests - reference labs Serology Indirect fluorescent Ab test for Ab Latex agglutination test for Ab

24 Treatment, Prevention and Control Tetracycline R. rickettsii Prompt treatment reduces morbidity and mortality No vaccine Prevention of tick bites (protective clothing, insect repellents) Prompt removal of ticks Can t control the reservoir

25 Typhus Group

26 Epidemic typhus Rickettsia prowazekii Brill-Zinsser disease Fluorescent-Ab staining Vector - Louse From: G. Wistreich, Microbiology

27 Clinical Syndrome - Epidemic typhus Incubation period approximately 1 week Sudden onset of fever, chills, headache and myalgia After 1 week rash Maculopapular progressing to petechial or hemorrhagic First on trunk and spreads to extremities (centrifugal spread) Complications Myocarditis, stupor, delirium (Greek typhos = smoke) Recovery may take months Mortality rate can be high (60-70%)

28 Laboratory Diagnosis - R. prowazekii Isolation possible but dangerous Serology

29 Treatment, prevention and Control Tetracycline R. prowazekii

30 Rickettsia typhi Murine or endemic typhus

31 Epidemiology - R. typhi Murine or endemic typhus Occurs worldwide برغوث Vector - rat flea Bacteria in feces Reservoir - rats No transovarian transmission Normal cycle - rat to flea to rat Humans accidentally infected

32 Flea

33 Clinical Syndrome- Murine Typhus Incubation period 1-2 weeks Sudden onset of fever, chills, headache and myalgia Rash in most cases Begins on trunk and spreads to extremities (centrifugal spread) Mild disease - resolves even if untreated

34 Laboratory Diagnosis - R. typhi Serology Indirect fluorescent antibody test Treatment: doxycycline

35 END

number Done by Corrected by Doctor Hamed Al Zoubi

number Done by Corrected by Doctor Hamed Al Zoubi number 17 Done by Ensherah Mokheemer Corrected by Waseem Abu Obeida Doctor Hamed Al Zoubi Today we are going to talk about the last two bacteria in this course which are Mycoplasma and Rickettsia. Let