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17 Cards in this Set
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Corynebacterium spp. -- upper respiratory
Pathogenic species C. diphtheriae: diphtheria C. ulcerans and C. pseudotuberculosis Occasionally produce disease. C. jeikeium: infections in ___________ Frequently resistant to multiple antibiotics. Group D-_ coryneforms: UTIs (C. urealyticum) Other non/low virulence spp. are normal flora. “diptheroids” |
Corynebacterium spp.
Pathogenic species C. diphtheriae: diphtheria C. ulcerans and C. pseudotuberculosis Occasionally produce disease. C. jeikeium: infections in immunosuppressed Frequently resistant to multiple antibiotics. Group D-2 coryneforms: UTIs (C. urealyticum) Other non/low virulence spp. are normal flora. “diptheroids” |
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C. diphtheriae - Characteristics
________ are reservoirs – URT and skin Gram ____ ; “____” shaped; motile?_____ spre forming? ______; catalase ____ Stained organisms often in palisades or “Chinese letters”. Three biotypes: gravis; mitis; intermedius colonial morphology _______ and biochemical reactions |
C. diphtheriae - Characteristics
Humans are reservoirs – URT and skin Gram POS; “club” shaped; non-motile Non-spore forming; catalase POS Stained organisms often in palisades or “Chinese letters”. Three biotypes: gravis; mitis; intermedius colonial morphology (gray-black) and biochemical reactions |
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C. diphtheriae Diseases
URT infection – toxinogenic strains Low-grade fever and sore throat Adherent pseudomembrane Tonsils and/or pharynx Cutaneous infection – Tox+ or Tox- strains insect bites; wounds; co-infected lesions Tropical climates – deep ulcers w typical pseudomembranes Toxic complications Myocarditis and/or polyneuritis |
C. diphtheriae Diseases
URT infection – toxinogenic strains Low-grade fever and sore throat Adherent pseudomembrane Tonsils and/or pharynx Cutaneous infection – Tox+ or Tox- strains insect bites; wounds; co-infected lesions Tropical climates – deep ulcers w typical pseudomembranes Toxic complications Myocarditis and/or polyneuritis |
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Pathogenesis
Is this invasive? _________ Respiratory symptoms from local effects of toxin. Pseudomembrane from back of throat to trachea. Cervical adenitis and/or edema …causes a condition known as “________" Respiratory obstruction Systemic effects Myocarditis – arrhythmia, congestive heart failure CNS - _____ t/f may paralyse? |
Pathogenesis
Non-invasive Respiratory symptoms from local effects of toxin. Pseudomembrane from back of throat to trachea. Cervical adenitis and/or edema … “bull neck” Respiratory obstruction Systemic effects Myocarditis – arrhythmia, congestive heart failure CNS - paralysis |
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C. diphtheriae – Virulence Factors
Diphtheria Toxin Encoded by toxin-converting _____ Expression under ___ iron Repressor is up-regulated in presence of Fe++ A/B subunit toxin It’s expressed as a single polypeptide (58 kDa), cleaved by a proteolytic enzyme A & B sub’s B fragment – __________ binding A fragment – internalized _______ activity |
C. diphtheriae – Virulence Factors
Diphtheria Toxin Encoded by toxin-converting phage Expression under low iron Repressor is up-regulated in presence of Fe++ A/B subunit toxin It’s expressed as a single polypeptide (58 kDa), cleaved by a proteolytic enzyme A & B sub’s B fragment – receptor binding A fragment – internalized enzymatic activity |
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Virulence Factors –cont.
Iron acquisition proteins ……and siderophores Other virulence genes facilitating invasion. Non-toxigenic strains Pathoadaptive event in Tox+ strains ?? BTW: lethal dose of DT = 0.1 mg/kg |
Virulence Factors –cont.
Iron acquisition proteins ……and siderophores Other virulence genes facilitating invasion. Non-toxigenic strains Pathoadaptive event in Tox+ strains ?? BTW: lethal dose of DT = 0.1 mg/kg |
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Diphtheria Epidemiology
Transmitted via _____ _________ Respiratory form And/or direct contact Cutaneous form And/or fomites (not frequent) Some infections followed by carrier state Months to years Sometimes for the life of the host |
Diphtheria Epidemiology
Transmitted via aerosol droplet Respiratory form And/or direct contact Cutaneous form And/or fomites (not frequent) Some infections followed by carrier state Months to years Sometimes for the life of the host |
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Epidemiology –cont.
10+ year long epidemic in Asia (respiratory) Approx. 10,000 cases per year; 4% mortality Rare in the U.S. _______ is required for school age children. Pre-vaccine freq. = 200 cases per million. Mortality reduced 4 logs. Currently less than __ cases per year. however… 1970’s – cutaneous epidemic outbreak in Seattle (over 1,000 cases) |
Epidemiology –cont.
10+ year long epidemic in Asia (respiratory) Approx. 10,000 cases per year; 4% mortality Rare in the U.S. Vaccination is required for school age children. Pre-vaccine freq. = 200 cases per million. Mortality reduced 4 logs. Currently less than 10 cases per year. however… 1970’s – cutaneous epidemic outbreak in Seattle (over 1,000 cases) |
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Treatment
One _________ of DT _________ neutralize effects. Vaccine is _______ toxin (“toxoid”) Prevents intoxication, but not _______. Combined with pertussis and _______ vaccines “DPT” Immunotherapy Passive immunization w anti-DT (from horse) |
Treatment
One serotype of DT Antibodies neutralize effects. Vaccine is inactivated toxin (“toxoid”) Prevents intoxication, but not colonization. Combined with pertussis and tetanus vaccines “DPT” Immunotherapy Passive immunization w anti-DT (from horse) |
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Listeria monocytogenes
Etiology of septicemia and abscesses in domestic animals; septicemia in humans.... and _____ ****! Mode of human infection: ________ Gram ___; ____-hemolytic; diptheroid-like ________ motility at 25oC Unlike corynebacteria 11 serotypes – flagella and teichoic acid 3 relevant to human diseases Serotype __ – almost all foodborne outbreaks. |
Listeria monocytogenes
Etiology of septicemia and abscesses in domestic animals; septicemia in humans... and meningitis****! Mode of human infection: foodborne Gram POS; beta-hemolytic; diptheroid-like Tumbling motility at 25oC Unlike corynebacteria 11 serotypes – flagella and teichoic acid 3 relevant to human diseases Serotype 4b – almost all foodborne outbreaks. |
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Epidemiology
Acquired through contaminated food. California,1985: 86 cases, 34% mortality! Mother-infant pairs From ingesting Mexican cheese**. Animal and human reservoirs. Fowl, ungulates, etc. Human intestinal colonization 2 to 12%. Can growth at ________ temps! True or false: Transplacental transmission** |
Epidemiology
Acquired through contaminated food. California,1985: 86 cases, 34% mortality! Mother-infant pairs From ingesting Mexican cheese. Animal and human reservoirs. Fowl, ungulates, etc. Human intestinal colonization 2 to 12%. Can growth at refrigerator temps! Transplacental transmission |
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Pathogenesis
Highly ________! Macrophages, epithelial cells, endothelial cells, dendritic cells, M cells, etc. ________ penetration of adjacent cells. Uses actin filaments to move through cell Forms “_____ _____” like Shigella Produces “fireworks” (like Shigella). Pop out of double-wall vacuole in fresh host cell http://www.youtube.com/watch?v=tKdwUERcV-U&NR=1 Coordinate regulation of multiple virulence factors. Immune response is ____-mediated Neutrophils and cytotoxic T-cells |
Pathogenesis
Highly Invasive! Macrophages, epithelial cells, endothelial cells, dendritic cells, M cells, etc. Lateral penetration of adjacent cells. Uses actin filaments to move through cell Forms “comet tails” like Shigella Produces “fireworks” (like Shigella) Pop out of double-wall vacuole in fresh host cell http://www.youtube.com/watch?v=tKdwUERcV-U&NR=1 Coordinate regulation of multiple virulence factors. Immune response is cell-mediated Neutrophils and cytotoxic T-cells |
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Disease Presentation
Diarrhea, abdominal pain, nausea Bacteremia (occult) sepsis Tropism for CNS! Includes brain stem and parenchyma < 1 month old: group B streptococci (70%) Listeria monocytogenes (25%)*** 60 years up: S. pneumoniae (70%) L. monocytogenes (24%) **** |
Disease Presentation
Diarrhea, abdominal pain, nausea Bacteremia (occult) sepsis Tropism for CNS! Includes brain stem and parenchyma < 1 month old: group B streptococci (70%) Listeria monocytogenes (25%) 60 years up: S. pneumoniae (70%) L. monocytogenes (24%) |
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Listeriosis –cont.
_________ infections common Intrauterine infection Stillbirth Disseminated at birth Puerperal infection Higher risk w AIDS 300-fold greater incidence of infection |
Listeriosis –cont.
Neonatal infections common Intrauterine infection Stillbirth Disseminated at birth Puerperal infection Higher risk w AIDS 300-fold greater incidence of infection |
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Definition of intrauterine
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Definition of intrauterine (adj)
Bing Dictionary in·tra·u·ter·ine [ ìntrə yóotərin ] 1.inside womb: existing, occurring, or designed to be used inside the womb |
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Virulence Factors
________ **** Modulates host cytoskeleton (actin) Induced phagocytosis ****__________ O (LLO) Confers _______ phenotype Pore-forming cytotoxin Facilitates escape from the vacuole Then inactivated by host proteases Also, pops double membrane to release bacteria which have moved into adjacent cells. |
Virulence Factors
Internalin Modulates host cytoskeleton (actin) Induced phagocytosis Listeriolysin O (LLO) Confers hemolytic phenotype Pore-forming cytotoxin Facilitates escape from the vacuole Then inactivated by host proteases Also, pops double membrane to release bacteria which have moved into adjacent cells. |
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Diagnosis and Treatment
Culture Blood CSF : Gram ____ rods are a dead give-away!**** Focal lesions Antibiotics _____ and others Vaccine None available |
Diagnosis and Treatment
Culture Blood CSF : Gram POS rods are a dead give-away! Focal lesions Antibiotics Penicillin and others Vaccine None available |
