Staphylococcus and Streptococcus Virulence Factors
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Questions and Answers

Which of the following virulence factors is associated with Staphylococcus aureus?

  • Lactose
  • Capsule (correct)
  • Hyaluronidase (correct)
  • Protein A (correct)

    • What is the common disease caused by Staphylococcus saprophyticus?

    Urinary tract infection (UTI)

    Staphylococcus epidermidis is catalase negative.

    False

    Match the following bacteria with their characteristics:

    <p>Streptococcus pneumoniae = Leading cause of bacterial meningitis in infants Staphylococcus aureus = Causes toxic shock syndrome Bacillus anthracis = Causes cutaneous anthrax Listeria monocytogenes = Causes listeriosis</p> Signup and view all the answers

    The virulence factor that allows Staphylococcus aureus to evade the immune response is _____.

    <p>Protein A</p> Signup and view all the answers

    Streptococcus pyogenes causes scalded skin syndrome.

    <p>False</p> Signup and view all the answers

    What test differentiates Staphylococcus saprophyticus from other Staphylococci?

    <p>Novobiocin resistance</p> Signup and view all the answers

    Which of the following tests is used for Streptococcus pneumoniae?

    <p>Optochin sensitivity test</p> Signup and view all the answers

    The organization of Corynebacterium diphtheriae appears similar to _____.

    <p>Chinese letters</p> Signup and view all the answers

    What significant disease is associated with Pasteurella multocida?

    <p>Respiratory disease</p> Signup and view all the answers

    What is the appearance of Mycoplasma pneumoniae colonies?

    <p>Fried egg appearance</p> Signup and view all the answers

    Ureaplasma urealyticum is commonly found in pregnancy-related complications.

    <p>True</p> Signup and view all the answers

    What characterizes primary syphilis?

    <p>Chancre</p> Signup and view all the answers

    Which of the following are symptoms of secondary syphilis?

    <p>Moth-eaten area</p> Signup and view all the answers

    In congenital syphilis, the tibia shows __________.

    <p>saber shin</p> Signup and view all the answers

    Match the following spirochetes with their associated diseases:

    <p>Treponema = Venereal syphilis Borrelia, B.burgdorferi = Lyme disease Leptospira = Leptospirosis Brachyspira = Relapsing fever</p> Signup and view all the answers

    Which of the following is a characteristic of Bartonella?

    <p>Short, pleomorphic, rod-shaped</p> Signup and view all the answers

    What disease is associated with Bartonella bacilliformis?

    <p>Oroya fever</p> Signup and view all the answers

    Neisseria gonorrhea is the most commonly reported STI.

    <p>False</p> Signup and view all the answers

    C. jejuni and C. coli are known to cause _______.

    <p>gastroenteritis</p> Signup and view all the answers

    What is the common test for Mycobacterium tuberculosis?

    <p>Tuberculin skin test</p> Signup and view all the answers

    Mycoplasmas are cell wall-deficient bacteria.

    <p>True</p> Signup and view all the answers

    What is a common characteristic of anaerobic bacteria?

    <p>Can grow in 5% oxygen</p> Signup and view all the answers

    What is the primary disease caused by Rickettsia rickettsii?

    <p>Rocky Mountain spotted fever</p> Signup and view all the answers

    The test for ________ is often used to determine the presence of tuberculosis.

    <p>tuberculin</p> Signup and view all the answers

    Which of the following mycobacterial species is associated with leprosy?

    <p>Mycobacterium leprae</p> Signup and view all the answers

    Study Notes

    CATALASE POSITIVE, GRAM-POSITIVE COCCI

    • Staphylococcus aureus:
      • Characteristics: Gram + cocci in clusters with PMN cells, grape-like clusters, staphyloxanthin (yellow or golden on BA)
      • Diseases: Toxic shock syndrome, Scalded skin syndrome, Septic arthritis, Nosocomial pneumonia, Acute endocarditis
      • Diagnostic tests: Catalase+, Coagulase+, b-hemolytic, PENICILLIN resistant, b-lactamase+
    • Staphylococcus epidermidis:
      • Characteristics: Small-medium, opaque, gray white colonies, slime-producing strains are extremely sticky
      • Diseases: Prosthetic valve endocarditis
      • Diagnostic tests: Catalase+, Coagulase-, Novobiocin sensitive
    • Staphylococcus saprophyticus:
      • Characteristics: Large, entire, very glossy, smooth, opaque, butyrous, convex colonies
      • Diseases: UTI in young females
      • Diagnostic tests: Catalase+, Coagulase-, Novobiocin resistant
    • Staphylococcus lugdunensis:
      • Diseases: Dog bite wound infections
    • Staphylococcus scheliferi:
      • No notable diseases or characteristics mentioned

    CATALASE NEGATIVE, GRAM-POSITIVE COCCI

    • Streptococcus pyogenes (Group A):
      • Characteristics: Gram + cocci in chains, round to oval shaped, occasionally forming elongated cells
      • Diseases: Scarlet fever, Rheumatic fever, Necrotizing fasciitis, Pharyngitis
      • Diagnostic tests: Catalase-, b-hemolytic, Bacitracin sensitive
    • Streptococcus agalactiae (Group B):
      • Characteristics: Capsule (most important virulence factor), grayish-white mucoid colonies surrounded by a small zone of β-hemolysis
      • Diseases: Pneumonia, Neonatal infections
      • Diagnostic tests: Catalase-, b-hemolytic, Bacitracin resistant, PYR-, CAMP+
    • Streptococcus pneumoniae:
      • Characteristics: Round, glistening, wet, mucoid, dome-shaped appearance
      • Diseases: Leading cause of bacterial meningitis, Pneumonia
      • Diagnostic tests: Catalase-, A-hemolytic, Bile solubility S, Optochin S, Quellung+
    • Enterococcus (Group D):
      • a. Enterococcus faecalis:
        • Diseases: UTI, Bacteremia, Endocarditis
        • Diagnostic tests: PYR+, 6.5% NaCl growth, LAP+, Cephalosporins, aminoglycosides resistant
      • b. Enterococcus faecium:
        • Diseases: UTI, Bacteremia, Endocarditis
        • Diagnostic tests: PYR+, 6.5% NaCl growth, LAP+, Cephalosporins, aminoglycosides resistant

    CATALASE POSITIVE, NON-BRANCHING, GRAM-POSITIVE BACILLI

    • Bacillus anthracis:
      • Characteristics: Spore-forming rods, large, in singles, pairs or serpentine chains, gray, flat, irregular swirling projections, "comet tails" or Medusa Head
      • Diseases: Cutaneous anthrax, Gastrointestinal anthrax, Inhalation anthrax
    • Bacillus cereus:
      • Characteristics: Spore-forming rods, large, in singles, pairs or serpentine chains
      • Diseases: Food poisoning (diarrhea and abdominal pain)
      • Toxins: Hemolysin BL, Nonhemolytic enterotoxin, Cytotoxin K, Cereulide

    LISTERIA, CORYNEBACTERIUM, AND SIMILAR ORGANISMS

    • Listeria monocytogenes:
      • Characteristics: Non-spore forming, short rod, occurs singly or short chains, end-over-end tumbling motility, umbrella-shaped pattern
      • Diseases: Listeriosis, Stillbirth
      • Diagnostic tests: Catalase-, VP+, CAMP+, Esculin+, PCR, Elek Test

    CATALASE NEGATIVE, NON-BRANCHING, GRAM-POSITIVE BACILLI

    • Erysipelothrix spp:
      • Characteristics: Short rods and long filaments, "bottle brush" appearance, delicate, curved, rods with pointed ends, occasional rudimentary branching
      • Diseases: Cellulitis (erysipeloid), Pharyngitis

    BRANCHING OR PARTIALLY ACID-FAST, GRAM-POSITIVE BACILLI

    • Nocardia asteroides:
      • Characteristics: Beaded appearance, pleomorphic, dry and heaped colonies, soil or musty basement odor
      • Diseases: Pulmonary (immunocompromised)
      • Diagnostic tests: Catalase+, Acid Fast (V)

    GRAM-NEGATIVE BACILLI AND COCCOBACILLI

    • Escherichia coli:
      • Characteristics: Greenish metallic sheen on EMB or MAC, Pili
      • Diseases: UTI, Watery diarrhea, Hemorrhagic colitis, HUS
      • Diagnostic tests: IMViC: ++ – -, Lactose+, Oxidase-
    • Shigella:
      • Characteristics: Bacillary dysentery, Fever, Watery then bloody diarrhea
      • Diseases: Bacillary dysentery
      • Diagnostic tests: Lactose-, H2S+, Lysine+, Indole-

    (Many more organisms and diseases listed in the original text, but I've condensed it to highlight the key points and characteristics of each organism.)### Burkholderia Complex

    • Not part of normal microbiota
    • Can cause severe infections in patients with cystic fibrosis or chronic granulomatous disease (CGD)
    • Burkholderia cepacia complex:
      • Can survive in human macrophages
      • Causes melioidosis
    • Burkholderia mallei:
      • Causes glanders in horses and related animals
      • Bipolar staining
    • Burkholderia pseudomallei:
      • Causes melioidosis
      • Can cause pneumonia, particularly ventilator-acquired pneumonia
      • Obligate aerobe
      • Oxidase positive
      • Produces pyocyanin, pyoverdin, and pyorubrin

    Pseudomonas spp.

    • Can form biofilms
    • Can cause pneumonia, particularly ventilator-acquired pneumonia
    • Third most common cause of nosocomial urinary tract infections
    • Associated with disrupted epidermis, cystic fibrosis, and immunocompromised patients
    • Oxidase positive
    • Produces pyocyanin (blue phenazine pigment)
    • Virulence factors:
      • Exotoxin A
      • Exoenzyme S and C
      • Proteolytic enzymes (elastases)
      • Hemolysis (phospholipase C)
      • Pili and adhesins
      • Alginate
      • Pyocyanin
      • Catalases

    Alcaligenes

    • Strict aerobic rods
    • Can cause bacteremia, ocular infections, pancreatic abscess, bone infection, and urinary tract infections
    • Catalase positive
    • Oxidase positive
    • Motile (1-12 peritrichous flagella)
    • Non-glucose utilizer

    Vibrio

    • Straight or slightly curved rods
    • Rapid or darting shooting-star motility
    • Oxidase positive
    • Glucose fermenter
    • Can cause cholera, bacteremia, septicemia, and gastroenteritis
    • Virulence factors:
      • Cholera toxin
      • Toxin coregulated pili
      • Zona occludens toxin
      • V. cholerae O1 and O139

    Aeromonas spp.

    • Straight rods with rounded ends or coccobacilli
    • Can cause gastroenteritis in children
    • Can cause severe watery diarrhea and hemolytic uremic syndrome (HUS)
    • Contains no or little WBC
    • Facultative anaerobe
    • Modified CIN (cefinase, indole, and nitrate reduction) test

    Chromobacterium violaceum

    • Straight rods with rounded ends
    • Produces violet pigment (violacein)
    • Facultative anaerobe
    • Can cause severe infections from human bites or clenched fist wounds
    • Assacharolytic
    • Oxidase positive
    • Catalase negative
    • Reduces nitrate to nitrite
    • Hydrolyzes ornithine and lysine### Bacterial Characteristics
    • Helicobacter pylori: Curved, helical or spiral, microaerophilic, small, translucent, circular colonies, produces urease, motile, urea breath test positive.

    Legionella

    • Mesophilic (20-45°C), oblige aerobic, faintly staining, thin, fastidious, small, filamentous, multiply within amoeba, motile, extrapulmonary.

    Brucella

    • Small coccobacilli, resemble fine grains of sand, catalase+, urease+, oxidase+, most strains are, hydrolyze urea, relative ability to produce H2S, titer of 1:160.

    Bordetella

    • Minute, faintly staining coccobacilli, small and shiny, resembling mercury drops, facultative, direct fluorescent antibody test, whole cell agglutination reactions.

    Francisella

    • Strict aerobes, transparent, mucoid, easily emulsified, "rabbits", tularemia, rabbit fever, deer fly fever, market man's disease, carbohydrate fermenter.

    Streptobacillus moniliformis

    • Facultative, nonaerobe, pleomorhic, long, tangled chains and filaments with bulbar swelling, "fried egg" appearance, nonmotile, urea-, lysine decarboxylase-.

    Spirillum minus

    • Gram-negative, helical, strictly aerobic, thick, spiral, with 2 or 3 coils and polytrichous polar flagella, rat-bite fever, Asia: sodoku.

    Neisseria

    • Diplococci with adjacent sides flattened, diplococci inside PMNs, "kidney- or coffee bean-shaped", oxidase+, sexually transmitted.

    Anaerobic Bacteriology

    • Strict anaerobes (0% oxygen), aerotolerant organisms (5% oxygen), foul odor, sulfur granules, brick red fluorescence under long wavelength UV light.

    Clostridia

    • Obligately anaerobe (or aerotolerant), produces yellow, ground glass colonies, chartreuse fluorescence upon exposure to UV light, horse stable odor, botulism, tetanus.

    Gram-Positive, Non-Spore Forming Bacilli

    • Eggerthella and Paraeggerthella: gram-positive filaments when crushed, "sulfur granules", periodontal disease, bacterial vaginosis.

    Gram-Negative Rods

    • Bacteroides fragilis group: mucosal surfaces of the human oral cavity and GIT, saccharolytic, bile resistant, nonpigmented, kanamycin resistant.

    Anaerobic Gram-Positive and Gram-Negative Cocci

    • Peptostreptococcus anaerobius and Parvimonas micra: gram-positive cocci vancomycin sensitive, colistin resistant, gram-negative cocci vancomycin resistant.

    Mycobacterium

    • Mycobacterium tuberculosis complex: primary TB, meningeal or military TB, latent TB, reactivation TB, tuberculin skin test or purified protein derivative test (PPD) test, T-Spot TB test, niacin test+.
    • Mycobacterium bovis: between M. tuberculosis and M. bovis, PYRAZINAMIDE sensitive.

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    Quiz on the virulence factors and characteristics of Staphylococcus aureus, Staphylococcus saprophyticus, Staphylococcus epidermidis, and Streptococcus pyogenes.

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