Micro Block 3-Pt 4

ptheodore's version from 2015-08-01 15:50


Question Answer
No cell wall so poor gm stain. Cell membrane has cholesterol “Fried egg” colonies on Eaton’s agar. (“Eat Fried Eggs w/ chol”)Mycoplasma pneumoniae
MCC “Walking pneumonia”. MCC Community-acquired atypical pneumoniaMycoplasma pneumoniae
Pathogenic only for humans. Adhesins; Arrests ciliary motion. Cross reactive antigens induce anti RBC autoantibodies (cold agglutinins).Mycoplasma pneumoniae
Elevated titer of cold agglutinins. Clumping in the fridgeMycoplasma pneumoniae
Treatment for Mycoplasma pneumoniaeErythromycin & Doxycycline

Mycobacterium tuberculosis

Question Answer
When Mycobacterium tuberculosis infects the bonesPott’s disease
Obligate Aerobic bacilli. Acid-fast bacteria/Carbol fuchsin (red). Mycolic acid cell wallMycobacterium tuberculosis
Appears as bright red bacilli (rods) in a sputum smear stained with the Ziehl-Neelsen stainMycobacterium tuberculosis
Purified Protein Derivative (PP) skin testMycobacterium tuberculosis
Lowenstein-Jensen (LJ) Media is used to growMycobacterium tuberculosis
TB virulence factor; Thick, hydrophobic barrier protects against free radicals and desiccation. Binds C3b to promote uptake by macrophages, but thick fatty acid layer prevents complement activation.Mycolic Acids
TB virulence factor; Prevents phagosome fusion with lysosomeCord Factor
TB virulence factor Inhibits macrophage activation and prevents phagosome fusion with lysosomeLipoarabinomannan (LAM)
Engulfed by alveolar macrophages (survive and multiply). Non-resident macs attracted. Causes fusion of macrophages to form Langhans giant cellsMycobacterium tuberculosis
Immune system responsible for warding off Mycobacterium tuberculosis & forming tubercles/granulomasCell Mediated Immune (CMI*)-Th1 Response
Caseous Necrotic core with fibrin and liquid, Giant cells, Tubercular Granuloma Mycobacterium tuberculosis
TB skin test negative, X-ray negativePrimary tuberculosis
TB skin test positive, X-Ray positive, Sputum positiveProgressive primary active infection
TB skin test positive, X-ray negavite for active diseaseLantent-dormant or vaccinated tuberculosis
Persistent cough with mucous; sometimes with blood (rusty sputum) &Weight lossMycobacterium tuberculosis
Ghon focus (granuloma); A 1-1.5 cm gray white area of caseous necrosis in sub-pleural location & Hilar lymph nodePrimary tuberculosis
Reactivation of dormant Mycobacterium tuberculosis. Original granuloma bursts or cavitates. Involves one or both apices in upper lobes. Frequently consequence of impaired immunity. Co-infection (esp. AIDS)Secondary Tuberculosis
Similar to Primary TB disease but much more sever: Cough, Fever, drenching night sweats, weight loss. and hemoptysis (coughing up blood)Secondary Tuberculosis
Disseminated TB, particularly immunocompromised. Cancer-like wastingMiliary Tuberculosis
Spread of TB in the lungs due to invasion into the bronchus or lymphatics. Spread to extra-pulmonary sitesMiliary Tuberculosis
Tuberculin Skin Testing Mantoux Method is considered what kind of a reactionType IV Hypersensitivity Reaction
Interpretation depends on person’s risk factors Ex. Low or no T cells; weak reactionTuberculin Skin Testing Mantoux Method
Patient’s blood samples is mixed with TB antigens in vitro. Test quantitates Interferon γ production by pre-sensitized cellsInterferon-gamma Release Assay (IGRA)
Treatment for Mycobacterium tuberculosis in the first 2 months (out 6)Rifampin (RNA Pol), Isoniazid (Mycolic acid), Pyrazinamide (cell membrane & wall), Ethambutol (cell wall) (RIPE)
Treatment for Mycobacterium tuberculosis in the first 2 -6 monthsRifampin (RNA Pol), Isoniazid (Mycolic acid)

Mycobacteria leprae

Question Answer
Targets dermal macrophages and Schwann cells of peripheral nerves. Affect humans and animals (armadillos)Mycobacteria leprae
High Cell Mediated Immune (Th1) Response. Flat macular lesions consisting of small granulomas with low bacterial numbers. Presentations yield LOSS OF FEELING.Tuberculoid (Mycobacteria leprae)
Lepramin skin test +ve. Maculoanasethetic patch with hypopigmented centre.Tuberculoid Leprosy (Mycobacteria leprae)
High humoral immune (Th2) Response; Raised papular lesions with no granuloma formation and high bacterial numbers. Loss of eyebrows is characteristic feature. Presentations yield LOSS OF FEELING.Lepromatous Leprosy (Mycobacteria leprae)
Lepramin skin test –ve. Glistening erythematous or skin-colored papules, nodules & plaques.Lepromatous Leprosy (Mycobacteria leprae)
Atypical pneumonia (Lady Windermere Syndrome) in elderly women. Highly disseminated disease in AIDS patients with CD4+ count <50 cells/ul often originating from GI tract.Mycobacterium avium –intracellulare Complex (MAC)
Treatement for Mycobacteria lepraeMacrolide (clarithromycin), Rifampin, Aminoglycoside (streptomycin)

Filamentous Gram +

Question Answer
Branching filaments. Weakly acid-fast, catalase (+). AEROBIC. Mycolic acid protects from complement. Cord factor interferes with phagocytic killing. Superoxides dismutase inactivate ROS.Nocardia asteroides
Nocardiosis: Opportunistic Abscess Infections pneumonia, pulmonary alveolar proteinosis, encephalitis, brain abscess, cutaneuos and sub-cutaneous mycetoma. Patients have history of dental diseaseNocardia asteroides
Short-chain mycolic acids in the cell wall of Nocardia interferes withComplement
Nocardia's virulence factor that prevents fusion of phagosome with lysosomeCord factor (glycolipid)
Branching filaments that causes Bronchio-pulmonary disease, Cutaneous and sub-cutaneous infections. Patient has history of chronic lymphocytic leukemia presents large nodules and chest pains. Primarily affects immuno-compromised (failure of T cells to activate macrophages.Nocardia asteroides
Treatment for Nocardia asteroidesCo-trimoxazole (Trimethoprim-Sulfamethoxazole, TMP-SMX)
Branching filaments. Gram +, ANAEROBIC, Sulfur granules (Foul smell). History of dental diseaseActinomyces israelii
Bacteria with sulfur (foul smell) granules. Transmitted via Dental work, inhalation, IUD. Patient present with opportunistic Abscess Infections: Pulmonary granuloma formation. Lumpy Jaw abscess, Uterine abscess, Chronic cutaneous mycetomaActinomyces israelii
Treatment for Actinomyces israeliiPenicillin


Question Answer
Type of pneumonia caused by Streptococcus pneumoniaeTypical Community acquired
Type of pneumonia caused by Haemophilus influenzaeTypical Community acquired
Type of pneumonia caused by Staphylococcus aureus (VAP)Typical Health-care Associated
Type of pneumonia caused by PseudomonasTypical Health-care Associated
Type of pneumonia caused by Klebsiella (VAP)Typical Health-care Associated
Type of pneumonia caused by NocardiaTypical
Type of pneumonia caused by Mycobacterium tuberculosisTypical
Type of pneumonia caused by Mycoplasma pneumoniaeAtypical Bacterial
Type of pneumonia caused by Legionella pneumophilaAtypical Bacterial
Type of pneumonia caused by Influenza virus types A and B (adults)Atypical Virus
Type of pneumonia caused by Parainfluenza virus (infants,children)Atypical Virus
Type of pneumonia caused by Respiratory syncytial virus RSV (infants,children)Atypical Virus