Community-acquired acute pneumonia:
B-Animal, or Environmental Exposure:
1- Legionella pneumophila pneumonia:
Microscopy:
-Gram’s negative rods (in nature)
Coccobacillary;
(in clinical specimens).
-Facultative intracellular parasites.
-Rods are motile by monotrichous flagella.
Transmission:
inhalation of aerosols from contaminated water produced by
showers, humidifiers, AC air condition.
N
Pathogenesis:
-Infection of resident alveolar
macrophage.
-Inhibits phagosome-lysosome fusion.
-Formation of phagosome enveloped by endoplasmic
reticulum; formation of replicative rod form; Autophage.
-TNF-α, and INF-γ Production;
monocytic infiltration of
air spaces.
-Alveolitis (Consolidation) and
micro-abscess formation.
-Bronchi are not affected.
N
Laboratory diagnosis:
-Staining of specimens by Gram’s stain and Gimesa stain.
-Grown on buffered charcoal yeast extract agar.
(Enriched media: L-cysteine, iron, α-ketoglutarate).
-Rapid identification:
1-Immunofluorescent
microscopy
2-PCR.
Treatment:
1-Macrolides: Azithromycin
2-Fluoroquinolones: Levofloxacin.
N
2-Pneumonic tularemia: (granulomatous infection):
: Francisella tularensis infection:
Microscopy and Cultural characteristics:
-Gram’s negative pleomorphic Coccobacillus with lipidrich capsule.
-Facultative intracellular parasite.
-Obligate aerobic bacteria.
N
- Grown on buffered charcoal yeast extract agar.
(Enriched media: L-cysteine, iron, α-ketoglutarate).
Transmission:
1-Inhalation of infectious aerosols.
2-Blood sucking arthropods bite; vector (ticks, mites) from
animals (rabbit, birds).
Pathogenesis and clinical presentation:
-Infection of alveolar macrophage; granuloma of lung:
Pneumonic tularemia.
N
Pathogenesis and clinical presentation:
N
-Infection of skin macrophage; ulcerative papule;
transmitted to regional lymph nodes; lymphadenitis:
Ulceroglandular tularemia ;(the most common
presentation).
-Hematogenous dissemination to lung from other sites.
(infection of APC of liver, spleen, bone marrow).
N
Treatment of Tularemia:
1- Aminoglycosides: Gentamicin or Streptomycin.
2-Ciprofloxacin and doxycycline.
3-Pneumonic Plague: Yersinia pestis infection:
Microscopy, virulence, and cultural characteristics:
- Gram’s negative coccobacillus.
- In sputum: Gram’s negative bipolar-stained bacilli.
-Encapsulated: F1, V, and W antigen; Antiphagocytic Ag.
-Lipopolysaccharide (LPS)
endotoxin.
-Plasminogen activator:
degrades fibrin.
N
Transmission:
1-Person-to-person: inhalation of droplets.
2-Vector-borne: insect bite(Fleas) from rodents (Rat).
Pathogenesis and clinical presentation:
-Infective dose:100-500 cells.
-Incubation: 2-8 days.
-Primary: Bubonic plague: Swollen tender regional lymph
node; bubo: lymphadenitis (Hemorrhagic necrosis).
-Septicemic plague: DIC, Purpura and ecchymoses; Black).
-Pneumonic plague: (Bronchopneumonia):
A-Primary: Inhalation of droplets.
B-Secondary: Hematogenous spread.
Transmission of Yersinia pestis (Plague):
N
N
Treatment of Plague:
-Pneumonic plague should be treated within 24 hours of
appearance of symptoms, (mortality rate: 100%).
-Aminoglycosides: Streptomycin, gentamicin.
-Fluoroquinolones and doxycycline.
4-Inhalation anthrax: Woolsorter’s disease:
Bacillus anthracis infection:
-Caused by Gram’s positive aerobic spore-forming bacilli.
-Transmission: inhalation of spores.
-Not a true pneumonia.
-Alveolar macrophage transfer the spore to mediastinal
and peribronchial lymph nodes.
N
Clinical presentation of inhalation anthrax:
-Hemorrhagic Mediastinal lymphadenitis.
-In 50% of inhalation cases; Anthrax meningitis ; extensive
hemorrhage of the leptomeninges; Dark-red “Cardinal’s
cap” appearance on autopsy.
Treatment:
-Only if multiple intravenous antibiotics and passive vaccine
administered prophylactically after spore exposure.
2- Hospital-acquired Pneumonia(Nosocomial):
Pneumonia acquired during or after hospitalization.
It occurs at least 72 hour after admission.
Who are at Risk?
-Patients on mechanical ventilation ( ICU).
-Immunocompromised patients.
-Other factors: malnutrition, heart and lung diseases.
Causative agents:
(Micro-aspiration of Oropharyngeal flora of hospitalized
patients):
MRSA, Pseudomonas, Enterobacter, Klebsella,
Serratia, Acinetobacter (person-to person) and VRE.
Chronic and Subacute Pneumonias:
Chronic granulomatous pneumonia:
1-Bacterial granulomatous pneumonia:
Mycobacterium tuberculosis:
-Acid-fast bacilli (Mycolic acid rich waxy capsule).
-Non-motile aerobic rods resists drying.
-Cultured on Lowenstein-Jensen agar.
-Stained by Z.N stain.
N
Pathogenesis and Clinical presentation:
Primary Tuberculosis
90% Latent dormant
tuberculosis
10% Progressive
active infection
Living- bacteria,
granuloma
Living bacteria
&granuloma
25% arrested
granuloma
Fibrosis or Calcification.
Enlarged
Tracheobronchial lymph
nodes .
AIDS, Old,
Children
75% Breaks
down
granuloma
Apical lung
cavities
Tuberculous
pneumonia
-Caseous material
discharged; necrosis
-Cavity creation.
LymphoHemo
Meningitis
Osteomyelitis
Diagnosis of Tuberculosis:
Clinical test:1-Tuberculin skin test. (DTH:48-72 hours).
Mantoux test:
(PPD: Purified Protein Derivative)
Results: Intermediate reaction=5-9mm.
Positive reaction=greater than 9mm.
2-Radiology.
Laboratory tests:
1-Z.N stain (Low sensitivity).
2-Culture.
3-PCR (highest sensitivity).
N
2-Fungal granulomatous pneumonia: (Endemic in America):
Transmission: Direct contact with birds and bats.
A-Coccidioidomycosis.
C-Blastomycosis.
B-Histoplasmosis.
D-Paracoccidioidomycosis.
Coccidioidomycosis:
Caused by dimorphic fungi
:Coccidioides immitis.
Infective stage:
Arthrospores
generated by septate hyphae.
Diagnostic stage:
Spherule filled with many endospores.
Fungal Pneumonia in AIDS patients:
1-Pneumocystis Pneumonia:
(The most common infection).
-Caused by Pneumocystis jiroveci (P.carinii).
-Yeast lacking ergosterol in cell membrane.
-Can not be treated by Amphotericin.
-Encysted forms infects alveoli; exudate; blocks gas
exchange.
-Treatment:
Sulfamethoxazole and
trimethoprim.
Cysts of Pneumocystis carinii ; Sliver stain.
N
2-Cryptococcosis:
(The second common cause of Fungal pneumonia in AIDS pat.).
-Causative agents: Cryptococcus neoformans.
-Yeast transmitted to man from birds (pigeon).
-Capsulated microbe.
-Meningitis in Immunocompromised host.
-Treatment: Fluconazole or amphotericin B.
The Budding capsulated yeast
Cryptococcus neoformans
as shown in India ink wet
mount .