Pericarditis Bacteria Flashcards
acid-fast (+)
PPD (+)
IGRA (+)
Mycobacterium tuberculosis
Gram (+) cocci in clusters
Catalase (+)
Coagulase (+)
Mannitol Salt Agar - ferments yellow
Beta-Hemolysis
Staph. aureus
Gram (+) cocci in clusters
Catalse (+)
Coagulase (-)
Mannitol (-)
Novobiocin (sensitive)
Staph. epidermidis
Gram (+) cocci in clusters
Catalase (+)
Coagulase (-)
Mannitol (varies)
Novobiocin (resistant)
Staph. saprophyticus
Gram (+) cocci in chains
Catalase (-)
Beta Hemolytic
Bacitracin sensitive
Strep. pyogenes
Gram (+) cocci in chains
Catalase (-)
Beta-hemolytic
Strep. agalactiase
Gram (+) lancet-shaped dilococci
Catalase (-)
Alpha hemolytic
Optichin sensitive
Bile Solubility (positive)
Strep. pneumoniae
Gram (+) cocci in chains
Catalase (-)
Alpha hemolytic
Optichin resistant
Bile Solubility (negative)
Viridans strep.
Gram (+) cocci in pairs
Catalase (-)
Gamma or alpha hemolytic
PYR (+)
Enterococcus faecalis
Gram (+) rods
Albert Stain (metachromatic granules)
Tellurite agar (black colonies)
Elek test
Corynebacterium diphtheriae
Dark-field microscopy, Serology (ELISA, Western Blot) PCR
Borrelia burgdorferi
Gram stain (-)
Oxidase (+)
Lactose Fermentation on MacConkey agar (non-fermenter)
Pyocyanin (blue-green)
Pseudomonas aeruginosa
Gram (-) coccobacillus
Choclate agar w/ factor V (NAD) and factor X(hemin)
Haemophilus species
Gram (-) Rod
Pitting on agar and bleach-like odor
Eikenilla corrodens
Septate hyphae w/ acute nagle-like branching
Aspergillus niger
Clinical Scenario: A 27-year-old IV drug user presents with fever, shortness of breath, and a new systolic murmur. Blood cultures grow Gram-positive cocci in clusters.
Diagnosis: Infective endocarditis (right-sided, tricuspid valve)
Staph aureus
Key Associations: IV drug users, skin abscesses, toxic shock syndrome, pneumonia, osteomyelitis
Clinical Scenario: A 65-year-old man with a history of recent prosthetic valve replacement presents with low-grade fever and fatigue. Blood cultures show Gram-positive cocci in clusters, catalase-positive, coagulase-negative.
Diagnosis: Prosthetic valve endocarditis
Staph. epidermidis
Key Associations: Biofilm formation on prosthetic valves, catheters, and joint implants
Clinical Scenario: A 10-year-old child presents with sore throat, fever, and tonsillar exudates. A rapid strep test is positive. Two weeks later, the child develops joint pain, carditis, and erythematous skin lesions.
Diagnosis: Acute rheumatic fever (Jones criteria: carditis, migratory arthritis, subcutaneous nodules, erythema marginatum, Sydenham chorea)
Strep. pyogenes
Key Associations: Strep pharyngitis → rheumatic fever or post-strep glomerulonephritis, necrotizing fasciitis, toxic shock-like syndrome
Clinical Scenario: A newborn delivered via vaginal birth at 38 weeks develops respiratory distress and sepsis within 24 hours. The mother was not screened for GBS.
Diagnosis: Neonatal sepsis and pneumonia
Strep. agalactiae
Key Associations: Neonatal meningitis, pneumonia, and sepsis (screen mothers at 35-37 weeks; give intrapartum penicillin prophylaxis if positive)
Clinical Scenario: A 60-year-old alcoholic presents with fever, productive cough, and rust-colored sputum. Gram stain of sputum shows Gram-positive diplococci.
Diagnosis: Community-acquired pneumonia
Strep. pneumoniae
Key Associations: MOPS infections (Meningitis, Otitis media, Pneumonia, Sinusitis); encapsulated, IgA protease, sickle cell disease susceptibility
Clinical Scenario: A 45-year-old man with a history of congenital heart disease presents with fever and a new heart murmur. He recently had a dental extraction. Blood cultures grow Gram-positive cocci in chains that are optochin-resistant.
Diagnosis: Subacute infective endocarditis
Viridans strep
Key Associations: Dental procedures → subacute bacterial endocarditis; forms biofilms on damaged heart valves
Clinical Scenario: A 75-year-old man hospitalized for a urinary tract infection develops fever and bacteremia. Blood cultures show Gram-positive cocci that grow in bile and 6.5% NaCl.
Diagnosis: Nosocomial UTI or endocarditis
Enterococcus faecalis & Enterococcus faecium
Key Associations: UTIs, biliary tract infections, infective endocarditis (subacute, elderly), vancomycin resistance (VRE)
Clinical Scenario: A 6-year-old unimmunized child presents with fever, sore throat, and difficulty breathing. Examination shows grayish-white pseudomembranes in the throat.
Diagnosis: Diphtheria
Corynebacterium diphtheriae
Key Associations: Toxin-mediated disease (exotoxin inhibits EF-2 → pseudomembranes, myocarditis, polyneuritis); Elek test for toxin
Clinical Scenario: A 45-year-old man from India presents with chronic cough, weight loss, night sweats, and hemoptysis. Chest X-ray shows cavitary lesions in the upper lobes.
Diagnosis: Pulmonary tuberculosis
Mycobacterium tuberculosis
Key Associations: Acid-fast bacillus, caseating granulomas, PPD-positive, Ghon complex (primary TB), miliary TB
