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54 Cards in this Set
- Front
- Back
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What are the signs and symptoms of Streptococcal Disease?
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-sore throat
-difficulty swallowing *may progress to scarlet or rheumatic fever |
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What is the Etiological agent for Strep and how does it enter the body?
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-Group A streptococi (S. pyogenes, pneumoniae, and faecalis)
-upper respiratory tract via respiratory droplets |
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How do you treat strep?
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-penicillin or other antibiotics
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What are the different types of hemolysis seen from the three types of strep infections?
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-Alpha= S. pneumoniae
-Beta= S. pyogenes -Gamma= S. faecalis |
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What is the suppurative form of strep?
Non-suppurative? |
-pus forming, strep throat
-scarlet fever |
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What is the M protein?
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-pili/fimbrae-like structures
-used for attachment (has specificity) -major virulence antigen (80 different types; superantigen) -anti-phaocytic; important for suppurative form *antibody agains M protein is protective against infection! |
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Describe Erythrogenic toxin.
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-produces by a lysogenic bacteriophage (superantigen)
-responsible for scarlet fever rash -"Dick Test" -predisposes tissue to damage by other toxins such as endotoxins so one becomes more sensitive |
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What is the Dick Test?
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-indicates exposure to Erythrogenic toxin
-detects circulating antibody to toxin |
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What are hemolysins?
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-Streptolysin S and O
-responsible for strep throat |
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What does Streptolysin S do?
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-oxygen stable hemolysin
-responsible for blood agar reaction -toxic to tissue, leukocytes, red blood cells |
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What do Streptolysin O do?
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-oxygen labile hemolysin
-binds cholesterol, cardiotoxic and other tissues |
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What is streptokinase used for?
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-spreadin factor
-dissolves fibrin blood clots |
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What is impetigo?
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-skin form of strep infection
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What are "flesh eating" bacteria known as?
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-necrotizing fasciitis
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What is Scarlet fever?
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-produces erythrogenic toxin (encoded by phage) that causes red rash, can be very severe
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What is a sequela disease?
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-a disease that is cuased by a preceding disease or inury in the same infividual
-a follow up disease *Rheumatic fever and Acute Glomerulonephritis |
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Why is S. pyogenes such a huge problem in terms of sequela diseases?
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-antigenic similarities to human tissues so if introduction occurs again, the body is also attacked!
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Describe Rheumatic fever.
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-M protein antibodies cause pharyngitis, joint inflammation, reddened skin, heart valve damage (cross-react with myosin protein in heart)
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How do you treat Rheumatic fever?
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-antibiotics (penicillin, erythromycin) if diagnosed early
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Describe Acute Glomerulonephritis.
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-from pharyngitis or skin infection
-blood in uring, edema, hypertension, severe pain -S. pyogenes antigen-antibody complexes lodge in glomeruli of kidney |
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How do you treat Acute Gomerulonephritis?
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-antibiotics liek penicillin and erythromycin
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Describe Necrotizing fasciitis.
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-extensive destruction of subcutaneous tissue
-due to massive immune (T cell) response to M protein and exotoxins -treatable with antibiotics but can cause death in ~30% of cases due to rapid effects |
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What are the three types of tuberculosis?
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-primary; initial case
-secondary; reestablished -disseminated; tuberculosis involving many systems |
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What are the signs of initial TB?
Later? |
-minor cough and mild fever
-difficulty breathing, chest pain, wheezing, and coughing up blood |
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What is the Etiological agent of TB?
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-Mycobacterium tuberculosis
-Gram +, acid-fast bacillus -slow growing (6W to colony) -Cord factor -mycolic acid in cell wall |
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What is special about mycolic acid in TB?
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-protects cell allowing them to remain viable for long periods in aerosol drops
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What is a cord factor in TB?
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-protein attached to daughter cells in parallel alignment
-in cell wall -required to cause disease |
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Describe pathogenesis of TB
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-lodges in lungs
-surviveswithin un-activated alveolar macrophages -elicits massive ummuve response and host cell damage -forms aggregates of macrophages called tubercles |
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How do you diagnose TB?
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-TB skin test identifies previous exposure to M. tuberculosis
-doesn't distinguish between active disease, chronic carriers, or those who have been vaccinated |
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How do you treat TB?
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-nicotinamide derivative (Isoniazid) plus 3-4 other antibiotics daily for six months
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How does isoniazid work?
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-inhibits enzymes required for synthesis of mycolic acid
-growth factor analog *M. tubercolulosis is highly mutable, leadin gto increases in antibiotic-resistant strains |
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What is pneumonia and what are the three types?
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-inflammation of lungs with fluid-filled alveoli and bronchioles
-lobar, mycoplasmal, nosocomial |
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What are the signs of bacterial pneumonias?
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-fever, chills, congestion, cough, chest, pain, and short, rapid breathing
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What is the etiological agent for pneumonia?
What is its susceptibility? |
-S. pneumoniae, Gr +
-Immunocompromised individuals, harmless normal flora for most people |
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What virulence factors does S. pneumoniae have?
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-adhesins, capsule, pneumolysin (binds cholesterol and makes pores in cells)
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What are some other etiological agents?
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-Mycoplasma pneumoniae, K. pneumoniae, Haemophilus influenzae, S. aureus, Yersinia pestis, Chlamydia spp.
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What are some systemic mycoses from fungus' that are involved in the respiratory system?
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-Aspergillosis
-Blastomycosis -Coccidioidomycosis -Histoplasmosis -Pneumocystis pneumonia (common fungal pneumonia of AIDS patients) |
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What is the most common environmental mold?
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-Aspergillosis flavus
*primary and opportunistic pathogen |
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What are signs/symptoms of Aspergillosis infection?
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-rash
-cough -respiratroy distress -allergic reaction |
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Describe Aspergillus flavus.
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-inhalation of fungal microconidia into lungs
-fungus ball is non-invasive, encapsulated hyphal mass there -found in soil and dexomposting organic matter and hay (Farmer's Lung) |
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How do you treat Aspergillosis?
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-disseminated aspergillosis and ivasive pulmonary aspergillosis are both generally lethat
*anti-fungal treatment done but usually ineffective |
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What are signs and symptoms for Blastomycosis?
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-flu like symptoms and chronic pneumonia
-systemic infections can produce painless lesions on the face and upper body or purulent lesions on various organs |
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Describe the Etiological agent of Blastomycosis.
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-Blastomyces dermatitidis
-yeast like with braod based buds -found in soil -enters through inhalation of fungal spores in dust -endemic to southeastern US and Canada |
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How do you treat Blastomycosis?
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-usually progressive so treatment ALWAYS required
-amphotericin B is effective |
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What is Valley fever?
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-Coccidioidomycosis
-caused from coccidioides immitis |
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What are the signs and symptoms of valley fever?
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-resembles pneumonia or tuberculosis
-primary is asymptotic or resembles the flu (40%) -produces coin lesion in lung -progressive coccidioidomycosis can occur months or decades after primary infection! Meningitis |
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Describe Coccidioides immitis.
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-dimorphic fungus
-hyphal form in soil -arthroconidia are inhaled |
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What is the epidemiology of Valley fever and how is it diagnosed?
Treatment? |
-endemic to SW US and Mexico; 10-50% are skin positive in endemic areas
-presence of spherules in clinical specimens -Amphotericin B |
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What are the signs of Histoplasmosis?
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-generally asymptomatic (95%) adn self-limiting
-some dry cough with blood tinged sputum and skin lesions (5%) |
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Describe the etiologlical agent of Histoplasmosis.
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-Histoplasma capsulatum
-budding yeast -enters by inhalation of conidia from soil contaminated with guano -conidia engulfed by macro's and begin to grow intracellularly |
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What is the epidemiology of Histoplasmosis and how is it treated?
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-endemic to eastern US but also found in parts of Africa and Central/South America
-Amphotericin B -Defining opportunistic infection for AIDS with TX persisting for life |
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What are the signs for PCP?
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-Pneumocystis Pneumonia
-difficulty breathing -mild anemia -hypoxia -fever |
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What is the etiological agent of PCP and how does it enter?
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Pneumocystis jiroveci (previously P. carinii)
-inhalation of droplets conataining the fungus |
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What is the treatment of PCP?
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-Timethoprim and sulfamehtaxazole (TMP-SMX)
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