Chapter 19 - Gram-Positive Bacilli in Medical Microbiology - (NSU - BIOL 251) - Microbiology by Talaro

Gram-Positive Bacilli

Bacteria characterized by thick peptidoglycan cell wall.

Endospore-formers

Bacilli that produce resistant spores for survival.

Non-endospore-formers

Bacilli that do not produce spores.

Sporulation cycle

Process of spore formation and germination.

Bacillus anthracis

Pathogen causing anthrax, found in soil.

Anthrax

Infection from spores; not communicable.

Cutaneous anthrax

Skin infection from spores; least dangerous.

Pulmonary anthrax

Inhalation of spores; severe respiratory illness.

Gastrointestinal anthrax

Ingestion of spores; affects digestive system.

Injection anthrax

Infection from injecting drug use; emerging concern.

Clostridium perfringens

Spores in soil; causes food poisoning and gas gangrene.

Food Poisoning

1 million cases annually in the USA.

Gas Gangrene

Infection requiring damaged tissue and anaerobic conditions.

Tetanus

Neuromuscular disease caused by Clostridium tetani.

Tetanospasmin

Neurotoxin causing muscle paralysis and spasms.

C. difficile

Causes antibiotic-associated colitis; disrupts gut flora.

Botulism

Severe intoxication from Clostridium botulinum toxin.

Infant botulism

Caused by ingested spores; leads to flaccid paralysis.

Wound botulism

Symptoms similar to food-borne botulism from wounds.

Listeria monocytogenes

Non-spore-forming; causes listeriosis from contaminated food.

Corynebacterium diphtheriae

Causes diphtheria; presents in pleomorphic bacilli.

Diphtheria

Upper respiratory infection; can cause severe complications.

Virulence factors

Traits that enhance pathogen's ability to cause disease.

Enterotoxins

Toxins causing gastrointestinal symptoms like diarrhea.

Anaerobic conditions

Environment lacking oxygen; necessary for certain bacteria.

Debridement

Removal of dead tissue to promote healing.

Hyperbaric oxygen therapy

Treatment to enhance oxygen delivery in infections.

Reservoir

Natural habitat where pathogens live and multiply.

Portals of entry

Routes through which pathogens enter the body.

Incubation period

Time between exposure and onset of symptoms.

Diphtherotoxin

Toxin that inhibits protein synthesis, causing cell death.

Pseudomembrane

Film formed in throat due to diphtheria inflammation.

Asphyxiation

Suffocation due to airway obstruction.

Endocytosis

Process of cell membrane engulfing substances.

Mycobacteria

Acid-fast bacilli, slow-growing, gram-positive bacteria.

Mycobacterium tuberculosis

Bacteria causing tuberculosis, no exotoxins produced.

Tubercle bacillus

Another name for Mycobacterium tuberculosis.

Epidemiology of Tuberculosis

Study of TB distribution and risk factors.

Primary TB

Initial infection stage, forms tubercles in lungs.

Infectious dose

10 cells required to cause primary TB infection.

Tubercles

Granulomas formed in response to TB infection.

Secondary TB

Reactivation of TB after primary infection.

Mortality rate

60% if untreated during secondary TB.

Extrapulmonary TB

TB spreading to organs outside the lungs.

Diagnosis of TB

Includes tuberculin testing and blood tests.

Mantoux test

Skin test for TB using PPD injection.

Interferon-gamma release assays

Blood test detecting TB bacterial products.

Mycobacterium leprae

Bacteria causing leprosy, slowest growing mycobacterium.

Leprosy

Chronic disease affecting skin and nerves.

Tuberculoid leprosy

Asymmetrical lesions causing local pain loss.

Lepromatous leprosy

Severe disfigurement and widespread infection.

Granuloma

Inflammatory mass formed during TB infection.

Caseous necrosis

Cheese-like tissue death in TB granulomas.

Cord factor

Mycobacterial virulence factor preventing immune destruction.

Catalase

Enzyme produced by mycobacteria, protects from oxidative stress.