Final Exam Review: Bacteria and Pathogenesis

Nucleoid

Large circular chromosome in bacterial cells.

Plasmids

Small DNA molecules often carrying virulence genes.

Cocci

Bacterial shape that is round.

Bacilli

Bacterial shape that is rod-like.

Spiral

Bacterial shape that is twisted.

Gram Positive

Retains stain, thick cell wall, one membrane.

Gram Negative

Does not retain stain, thin cell wall, two membranes.

Peptidoglycan

Polymer that affects bacterial cell shape.

Teichoic Acid

Polymers affecting Gram-positive cell development.

Obligate Aerobes

Require oxygen for metabolic activity.

Facultative Anaerobes

Can use both aerobic and anaerobic respiration.

Obligate Anaerobes

Oxygen is toxic; use fermentation.

Spores

Non-active, resistant structures formed by bacteria.

Pathogenicity

Ability of an organism to cause disease.

Pathogen

Organism capable of causing disease.

Virulence

Degree of pathogenicity of a bacterium.

Primary Pathogens

Always harmful bacteria to hosts.

Opportunistic Pathogens

Harmful only under certain conditions.

Commensal Bacteria

Generally beneficial bacteria in the body.

Antiphagocytosis

Capsule prevents immune system from attacking.

Exotoxins

Toxins secreted by bacteria affecting host cells.

Endotoxins

Part of Gram-negative bacteria, activates immune response.

Antimicrobial

Substances that kill or inhibit microbes.

Bactericidal

Antibiotics that kill bacteria.

Bacteriostatic

Antibiotics that inhibit bacterial growth.

Minimal Inhibitory Concentration

Lowest antibiotic concentration preventing bacterial growth.

Beta-lactams

Antibiotics interfering with peptidoglycan cross-linking.

Glycopeptides

Inhibit peptidoglycan synthesis; last resort antibiotics.

Aminoglycosides

Bind to bacterial ribosomes, blocking protein synthesis.

Tetracyclines

Bacteriostatic antibiotics with broad-spectrum activity.

Fluoroquinolones

Inhibit DNA topoisomerase, broad-spectrum antibiotics. (blocks topoisomerase which helps bactier unwind to copy their DNA; block them, the bacteria can’t divide = bacterial death)

Beta-lactamase

Enzyme that destroys beta-lactam antibiotics.

Staphylococcus Aureus

Pathogenic bacteria producing various harmful toxins.

Alpha-toxin

Pore-forming toxin affecting cell membranes.

Superantigens

Toxins causing massive cytokine release.

Enterotoxins

Toxins causing food poisoning symptoms.

Gram-positive

Bacteria that retain crystal violet stain.

Facultative anaerobes

Can grow with or without oxygen.

Catalase positive

Produces enzyme that breaks down hydrogen peroxide.

Protein A

Binds to Fc region of antibodies.

Clumping factor

Coagulase that promotes bacterial clumping.

Fibronectin-binding proteins

Facilitates bacterial adhesion to host cells.

Toxin-mediated disease

Diseases caused by bacterial toxins.

Bullous impetigo

Skin infection with blisters caused by toxins.

Exfoliative toxin

Causes skin peeling in infections.

Scalded skin syndrome

Severe skin condition from exfoliative toxin.

Toxic shock syndrome

Severe illness caused by superantigens.

Coagulase-negative staph

Bacteria lacking coagulase, often form biofilms.

S. Saprophyticus

Causes urinary tract infections, especially in women.

Streptococcus

Small, round bacteria found in chains.

Alpha-hemolytic

Partial lysis of red blood cells.

Beta-hemolytic

Complete lysis of red blood cells.

Group A strep

Causes pharyngitis and skin infections.

Scarlet fever

Rash and fever from Group A strep infection.

M protein

Helps bacteria evade immune response.

Corynebacteria

Gram-positive rods causing diphtheria.

Diphtheria toxin

A-B toxin causing cell death.

Mycobacteria

Bacteria causing tuberculosis and leprosy.

Acid-fast

Resistant to decolorization by acid-alcohol.

Mycolic acid

Component of thick cell wall in mycobacteria.

Lipoarabinomannan

Similar to LPS, found in mycobacterial cell wall.

Niacin

Vitamin used for tuberculosis testing.

Granulomas

Immune response causing localized inflammation.

M. Tuberculosis

Bacteria causing tuberculosis, infects lungs.

Tuberculin test

Skin test for tuberculosis exposure.

Acid-fast smears

Microscopy technique for detecting mycobacteria.

Reactivation

Return of tuberculosis due to stress.

Necrosis

Tissue death due to infection.

Isoniazid

Antibiotic used to treat tuberculosis.

Ethambutol

Antibiotic targeting tuberculosis bacteria.

BCG vaccine

Vaccine derived from M. Bovis for TB.

Leprosy

Infection caused by M. Leprae.

Schwann Cells

Nerve cells infected by leprosy.

Tuberculoid leprosy

Localized leprosy with strong immune response.

Lepromatous leprosy

Widespread leprosy with extensive damage.

Enterobacteriaceae

Family of gram-negative bacteria, includes E. coli.

Pili

Hair-like structures for bacterial attachment.

Alpha Hemolysin

Toxin causing red blood cell damage.

Shiga toxin

Cytotoxic toxin modifying ribosomes.

Enterotoxigenic E. coli

Causes traveler's diarrhea via toxins.

Type III secretion system

Bacterial syringe for injecting virulence factors.

Enterohemorrhagic E. coli

Causes bloody diarrhea, linked to food.

Shigellosis

Dysentery caused by Shigella bacteria.

Virulence factors

Molecular traits enhancing bacterial pathogenicity.

Coli

No flagella; very low infectious dose.

M cells

Targeted by pathogens for invasion and uptake.

Salmonella

Complex antigens; causes systemic infections.

Typhoid fever

Chronic infection; spreads through blood.

Yersinia

Slow-growing; causes plague and pseudotuberculosis.

Invasin

Protein aiding Yersinia in cell invasion.

Vibrio Cholerae

Causes cholera; linked to contaminated water.

Cholera toxin

A-B toxin causing massive diarrhea.

cAMP

Cyclic AMP; regulates chloride secretion.

El Tor strain

More resilient; causes subclinical cholera infections.

Helicobacter

Curved, gram-negative; causes stomach ulcers.

CagA

Protein disrupting normal cell functions.

Clostridium

Gram-positive; spore-forming; obligate anaerobes.

C. Perfringens

Causes gas gangrene; hemolytic alpha-toxin.

Gas gangrene

Wound infection; muscle destruction from toxins.

C. Botulism

Neurotoxin causing flaccid paralysis.