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Biology 431 Gram (+), Acid-Fast, and Wall-Less Rods Chapters 25-27, 29, 44

Biology 431 Gram (+), Acid-Fast, and Wall-Less Rods Chapters 25-27, 29, 44. Bacillus anthracis Soil/spores; historically - agriculture/veterinary disease. Virulence Factors Antiphagocytic protein capsule - poly-D-glutamic acid Protective Ag - binds receptor (broadly expressed)…

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Biology 431 Gram (+), Acid-Fast, and Wall-Less Rods Chapters 25-27, 29, 44

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  1. Biology 431Gram (+), Acid-Fast, and Wall-Less RodsChapters 25-27, 29, 44

  2. Bacillus anthracisSoil/spores; historically - agriculture/veterinary disease Virulence Factors Antiphagocytic protein capsule - poly-D-glutamic acid Protective Ag - binds receptor (broadly expressed)… Binding initiates cleavage that form entry pores for… LF: destroys MAP, leading to lysis - macrophage EF: increases cAMP levels, leading to edema One of two pathogenic species among 70 - with most virulence factor genes on plasmids pXO1-2.

  3. Anthrax Diseases Historically - agriculture and veterinary disease Cutaneous: skin lesions, edema, 20% fatal/untreated GI: nausea, vomiting, systemic, ~100% fatal/untreated Inhaled: latency, systemic ~100% fatal /untreated Treated with penicillin, ciprofloxacin - varying resistance Vaccination of animals, animal workers, military Only relative cereus causes some cases of diarrhea and ocular infections using 2-3 toxins.

  4. Listeria monocytogenesSoil, feces, plant decay; 5% people carry in GI tracts Virulence Factors INL protein - binds receptor, uptake, acid pH activates… Listeriolysin O - phospholipase, releases to cytoplasm Bacteria divide - propelled by ActA, nucleates host actin Actin/bacteria shoot into neighboring cells - invasion Outcome is movement into GI lining, MALT, macrophage; spreading to liver, spleen - systemic.

  5. Listeria Diseases Neonatal/Early: in utero,highly fatal systemic Neonatal/Late: post-birth, meningitis and septicemia Adults: flu-like bacteremia, GI, meningitis Treated with penicillin; resistant to cephalosporins Vaccination of animals, animal workers, military Relative Erysipelothrix - skin infections or blood/endocarditis; prominent veterinary/agriculture.

  6. Mycobacterium DiseasesLimited reservoirs for pathogens; poorly understood. Virulence Factors 60% lipid/mycoloic acid wall - resistance, more in lab Pigments/carotenes - can oxidize defensive chemicals Quiescent? No spores - but spore-like genes? Latent? Intracellular survival, alveolar macrophage - cord factor? Unusually - NO known toxins… disease level:# agents Injected TB test = PPDs that stimulate memory T cells

  7. M. tuberculosis Disease Defenses react - WBC, complement, O2 radicals… Eventually, fibrin encapsulates, protects - Ca/tubercles 5% exposed develop active TB in 2 years (5-10% later) 10% if HIV, more likely to develop miliary (systemic) Multidrug cocktail 6-9 months - isoniazid (wall-specific) BCG (M. bovis) - live attenuated, efficacy? HIV?

  8. M. leprae Disease - a.k.a. Hansen’s Disease Spread by contact, armadillos only known US reservoir Tuberculoid - strong T; granulomas, skin macules, mild Lepromatous - strong Ab; dermal/nerves, disfiguring Since 1985 - dropped by 90% worldwide, WHO efforts

  9. M. avium Complex (MAC) Disease Ubiquitous in water, plants, soil - ingested, inhaled… Most serious in IC/AIDS - pneumonia, systemic Even relatives like bovis - similar problems in IC/AIDS Whole group of “rapidly growing” species (also soil and water) associated with wound infections, nosocomial.

  10. Corynebacterium diphtheriaeExtremely prevalent in/on plants, animals as flora Virulence Factors Short-chain mycolic acid in wall (hint - Mycobacterium) Only B-phage-lysogenized strains are virulent… Tox gene makes A-B exotoxin - 1 of many examples… B = binds host receptor, translocates protein into cell A = catalytic, inactivates EF2 ribosome/translation factor Host receptor = heart and nerve epidermal growth factor

  11. Diphtheria Disease Cutaneous: pre-existing breaks - worsening ulcer Respiratory: 2-6 days - toxin damages pharynx… Exudate, pseudomembrane, obstructed airway Neutralizing IgG (blood exposure); toxoid DPT vaccine Most relative species cause nosocomials (sepsis, UTI).

  12. MycoplasmaAlthough wall-less, genetically related to Gram (+) Virulence Factors and Diseases Smallest - no cell wall but sterols, drug implications Some surface Ag cross-react with human tissues P1 binds host epithelial cilia - ciliostasis, cell death, SAg pneumoniae - mild walking pneumonia, 2-6 weeks genitalium - urethritis; hominis - PID, postpartum fever Treated with non-wall drugs; condoms for STD’s

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