1. PHARMACEUTICAL MICROBIOLOGY -1I PHT 313
Dr. Rasheeda HamidAbdalla
Assistant Professor

2. Rickettsiae

3. Objectives
Rickettsiae
Chlamydiae
Mycoplasma

4. Rickettsiae
The group of organisms known as rickettsiae (family Rickettsiaceae) consists of three genera:
Rickettsia
Ehrlichia
Coxiella

5. Rickettsiaceae
Rickettsia, Ehrlichia, and Coxiella have a number of features in common:
They grow only inside living host cells (obligately intracellular parasites)
Most rickettsial infections are tansmitted by infected arthropods
Rickettsial diseases are generalized infections

6. General characteristics
They are small, rod like or coccobacillary shaped
Have a typical double-layered gram-negative cell wall.
Visualized under the light microscope with one of the polychrome stains, such as Giemsa

7. Pathogenesis
Parasitized endothelial cells through out the circulatory system
Transmitted to human by arthropods (fleas, ticks, mites, or lice).
Reservoirs are rodents, humans, or arthropods
Following a bite the organisms are taken into cells by a process similar to phagocytosis.
The organism produce phospholipase that damage host cell membrane ,and facilitate cell entry

8. Pathogenesis (cont’d)
The organisms multiply in both the nucleus and cytoplasm of host cells.
host cells are killed, and rickettsia spread throughout the body
Focal thrombi are formed in various organs including the skin
Variety of small hemorrhages and hemodynamic disturbances created the symptoms of the illness

9. Clinical significance
1-Rocky Mountain spotted fever
Caused by Rickettsia rickettsii
Human infection is initiated by the bite of an infected wood or dog tick

10. Clinical significance
Symptoms:
High fever
Malaise
Prominent rash
In untreated cases, vascular disturbances and myocardial or renal failure may ensue.

11. Rocky mountain spotted fever rash

12. Clinical significance (cont’d)
2-Other spotted fevers:
Tick-borne spotted fevers similar to Rocky Mountain spotted fever
They vary in severity
Caused by
R. conorii, R. canada, and R. sibirica
3-Louseborne (epidemic) typhus
is caused by Rickettsia prowazekii
[Note: Epidemic typhus is a different disease from salmonella-induced typhoid fever

13. Clinical significance (cont’d)
4-Other forms of typhus-like fever: Murine (endemic) typhus
Caused by R. typhi, is a clinically similar, but usually milder disease than that caused by R. prowazekii

14. Laboratory identification
Serological tests
Infected cells detection by immunofluorescence or histochemical procedures on some clinical samples, such as punch biopsies from areas of rash

15. Treatment
Doxycycline is the drug of choice for the treatment of Rocky Mountain spotted fever in both adults and children, except for pregnant women who should be treated with chloramphenicol

16. Prevention of infection
Prevention depends on vector control
Personal protection
Vaccines are not currently licensed for use in the United States

17. Coxiella Coxiella burnetii,the causal agent of Q fever
Transmission to human:
Inhalation of infected dust
Via other mucous membranes, abrasions
Gastrointestinal tract through consumption of milk from infected animals.

18. Clinical significance
C. burnetii reproduces in the respiratory tract and then (in the absence of treatment) is disseminated to other organs.
Classic Q fever is an interstitial pneumonitis

19. Laboratory identification
Serologic assays are the principal means of specific diagnosis.
Treatment and prevention
Doxycycline is the drug of choice for treatment.
A vaccine has been reported to be of limited use in occupationally exposed individuals.

20. Chlamydiae Chlamydia is a genus of small bacteria
Obligate intracellular parasites
They grow in cytoplasmic vacuoles
The genus is divided into three species:
Chlamydia trachomatis,
Chlamydia psittaci,
Chlamydia pneumoniae. ..

21. C. trachomatis cause diseases of
Genitourinary tract, including many cases of nongonococcal urethritis
Ocular infections such as trachoma.
C. psittaci and C. pneumoniae infect the respiratory tract.
C. psittaci causes psittacosis (parrot fever,)
C. pneumoniae causes atypical pneumonia

22. General Features of Chlamydiae
Chlamydiae are small
Round-to-ovoid
Chlamydial cell wall resembles a gram-negative envelope
possess ribosomes and synthesize their own proteins and, therefore, are sensitive to antibiotics that inhibit this process, such as tetracyclines and macrolides

23. Pathogenesis The extracellular infectious form, the elementary body
The elementary body is taken up by phagocytosis into host cells,
The elementary body prevents fusion of the phagosome and lysosome
The particle reorganizes into a larger, noninfectious reticulate body
Reticulate body divides, forming an inclusion body.
Reticulate bodies condense to become new infectious elementary bodies.
The elementary bodies released from the cell by cytolysis, ending in host cell death

24. Laboratory identification
Direct immunofluorescence is also a common and useful procedure
In C. trachomatis only, a matrix of glycogen like material accumulates in the inclusions, which can be shown by staining with iodine.

25. Clinical significance
Chlamydia trachomatis:
divided into a number of serotypes, which correlate with the clinical syndrome they cause
C. trachomatis causes:
Genitourinary infections
Eye infections

26. Genitourinary infections
1-Nongonococcal urethritis (NGU)
Transmission:
Sexual contact
During birth
In males, the urethra is the principal locus of infection
Females may present with cervicitis and/or urethritis

27. Genitourinary infections (cont’d)
2-Lymphogranuloma venereum (LGV):
Invasive sexually transmitted disease
causes by C. trachomatis serotypes L1, L2, and L3

28. Eye Infection 3-Trachoma
inflamed granulation
on the inner surface of
the lids.
4-Neonatal conjunctivitis and other infections
5-Inclusion conjunctivitis in adults

29. Laboratory identification
-Direct tests: Microscopic examination using direct fluorescent antibody staining reveals characteristic cellular cytoplasmic inclusions -Culturing in tissue culture -PCR -Detection of serotypes: by immunofluorescence staining with monoclonal antibodies

30. Treatment and prevention
Azithromycin and tetracycline are currently the drugs of choice
Erythromycin used in small children and pregnant women because of the effects of tetracyclines on calcification
A topical ocular preparation containing erythromycin effective prophylaxis in newborns
Detection a particular problem in asymptomatic individual followed by specific treatment is the key means of control.

31. Chlamydia psittaci Psittacosis (ornithosis) a zoonotic disease
Transmitted to humans by inhalation of dust contaminated with respiratory secretions or feces of infected birds.
Affect lower respiratory tract
Causing fever, dry cough, and flulike symptoms bilateral patchy pulmonary infiltration
Enlargement of liver and spleen is a frequent accompanying feature
Doxycycline or erythromycin is effective in eradicating symptoms

32. Chlamydia pneumoniae Chlamydia Pneumoniae
C. pneumoniae is a respiratory pathogen causing pharyngitis, sometimes followed by laryngitis, bronchitis, or interstitial pneumonia.
The organism is sensitive to doxycycline and erythromycin

33. Mycoplasma Mycoplasma species : Distributed in nature
Commensals found in the mouth and genitourinary tract of humans and other mammals
Three Mycoplasma species associated with human disease

34. Mycoplasma pneumoniae
which is the cause of a primary atypical pneumonia,
Mycoplasma hominis
Ureaplasma urealyticum
which are associated with a variety of genitourinary diseases, such as
Urethritis
pelvic inflammatory disease, and
intrapartum infections

35. General Features of Mycoplasmas
Lacking cell walls,
Mycoplasmas are enclosed instead by a membrane composed of a lipid bilayer
pleomorphic.
can be grown in cell-free media
medically important species are facultative anaerobes
some genus members are strict anaerobes
Fastidious
Require cholesterol and fatty acids for growth

36. Mycoplasma Pneumoniae
M. pneumoniae is transmitted by respiratory droplets
causes a lower respiratory tract infection (unlike typical lobar pneumonia)
bronchitis,
pharyngitis,
nonpurulent otitis media

37. Pathogenesis
M. pneumoniae possesses a membrane-associated protein, P1, which functions as a cytoadhesin.
which binds to ciliated bronchial epithelial cells.
and inhibit ciliary action.
affected mucosa desquamate, and an inflammatory response develops in bronchial and adjacent tissues
The disease is an expression of host-specific immune response rather than damage created by the organism itself.
In infected individuals, organisms are shed in saliva for several days before onset of clinical illness.

38. Clinical significance
Primary atypical pneumonia (lower respiratory tract disease) is the best known form of M. pneumoniae infection (walking pneumonia)
Upper respiratory tract and ear infection more frequent

39. cont’d)) Clinical significance
Symptoms :
headache, fever, chills, and malaise.
dry or scantily productive cough.
Earache
In the absence of preexisting compromise the disease remits after 3-10 days without treatment
Complications are rare, but include CNS disturbances, a rash and mild, hemolytic anemia

40. Laboratory identification
Sputum samples or throat swabs can be cultured on special media
Serologic test.

41. Treatment
M. pneumoniae is sensitive to doxycycline or azithromycin.

42. Genital Mycoplasmas Mycoplasma hominis Ureaplasma urealyticum
Are common inhabitants of the genitourinary tract
The major clinical condition associated with M. hominis is postpartum or postabortal fever
U. urealyticum causes urethritis in men.
In women causes endometritis.
M. hominis resistant to erythromycin, in contrast to other mycoplasmas.
Tetracycline is effective for specific treatment.

43. Other Mycoplasmas
AIDS-associated mycoplasma, or
M. incognitus

44. THANKS