Block 3 Microbiology Summary

These flashcards cover various pathogenic bacteria discussed in Block 3 Microbiology, including their characteristics, diseases they cause, and key diagnostic and treatment points.

Neisseria Gonorrhea

Causes gonorrhea, septic arthritis, neonatal conjunctivitis, pelvic inflammatory disease, and Fitz-Hugh-Curtis syndrome; transmitted sexually or perinatally.

Meningococcus

Causes meningococcemia with petechial hemorrhages and gangrene of toes, meningitis, and Waterhouse-Friderichsen syndrome; transmitted via respiratory secretions.

Moraxella catarrhalis

Gram-negative diplococci and oxidase-positive, causing otitis media and sinusitis; resistant to 1st-generation β-lactams.

Haemophilus influenzae

Gram-negative coccobacilli, facultative anaerobe with capsulated (Hib) and non-capsulated (NTHi) types; causes infections like meningitis and pneumonia.

Bordetella pertussis

Causes whooping cough; attachment mediated by filamentous hemagglutinin and fimbriae; toxin-related pathogenesis.

Legionella pneumophila

Causes Legionnaire's disease through contamination of water; diagnosis includes BCYE agar culture.

Pseudomonas aeruginosa

Opportunistic pathogen associated with pulmonary infections, skin infections, and urinary tract infections, known for blue-green pigment production.

Escherichia coli

Gram-negative rod with various pathogenic strains causing UTIs, septicemia, and gastroenteritis with specific virulence factors.

Salmonella

Gram-negative rods that are strictly pathogenic via fecal-oral route; includes S. typhi as a major pathogen.

Shigella

Highly infectious non-motile pathogen causing bacillary dysentery through low infective dose.

Yersinia pestis

Causes plague with forms including bubonic and pneumonic; transmission by flea bites or respiratory droplets.

Klebsiella pneumoniae

Gram-negative rod, lactose-fermenting, associated with distinct mucoid sputum in pneumonia and opportunistic infections.

Proteus spp.

Gram-negative rods, non-lactose fermenting, known for urease production leading to urinary stones.

Campylobacter

Curved Gram-negative rods that cause gastroenteritis; can lead to Guillain-Barre syndrome as a post-infection complication.

Helicobacter pylori

Gram-negative spiral-shaped bacterium linked to gastric ulcers and cancers through urease and vacuolating toxins.

Treponema pallidum

Causes syphilis, transmitted sexually or via blood; diagnosis includes serologic testing and dark field microscopy.

Borrelia burgdorferi

Causes Lyme disease, characterized by bulls-eye rash and transmitted by ticks.

Brucella spp.

Small Gram-negative bacilli associated with undulant fever, commonly from unpasteurized dairy products.

Mycoplasma pneumoniae

Lacks a cell wall and causes atypical pneumonia; treatment includes macrolides.

Chlamydia trachomatis

Obligate intracellular pathogen causing various STDs, diagnosed via ELISA and NAAT.

Rickettsiae

Intracellular pathogens leading to diseases like Rocky Mountain spotted fever; transmitted by ticks.

What are the key virulence factors of Neisseria Gonorrhea?

Pili (for attachment and antigenic variation), Opa proteins (opacity proteins for adhesion), Por proteins (porin proteins for nutrient uptake and resistance), Lipooligosaccharide (LOS, an endotoxin), and IgA protease.

What are the key virulence factors of Meningococcus?

Polysaccharide capsule (for resistance to phagocytosis), Lipooligosaccharide (LOS, an endotoxin), IgA protease, and Pili (for attachment).

What are the key virulence factors of Moraxella catarrhalis?

Adhesins (for attachment to host cells) and Endotoxin (LOS).

What are the key virulence factors of Haemophilus influenzae?

Polyribitol phosphate (PRP) capsule (for Hib strains, enabling evasion of phagocytosis), IgA protease, Fimbriae (for adherence), and Lipooligosaccharide (LOS, an endotoxin).

What are the key virulence factors of Bordetella pertussis?

Pertussis toxin (inhibits host defenses), Adenylate cyclase toxin, Tracheal cytotoxin (damages ciliated cells), Filamentous hemagglutinin (for attachment), and Fimbriae (for attachment).

What are the key virulence factors of Legionella pneumophila?

Icm/Dot secretion system (for intracellular survival), Flagella (for motility), and LPS (lipopolysaccharide).

What are the key virulence factors of Pseudomonas aeruginosa?

Exotoxin A (inhibits protein synthesis), Endotoxin (LPS), Elastase, Phospholipase C, Pili/Flagella (for motility and adherence), Alginate capsule (mucoid phenotype, promotes biofilm formation), Pyocyanin and Pyoverdine (pigments with toxic properties).

What are the key virulence factors of Escherichia coli?

LPS (endotoxin), K antigen capsule, Fimbriae (pili for adherence), Shiga-like toxins (STEC strains), Heat-labile and Heat-stable toxins (ETEC strains), and Alpha-hemolysin.

What are the key virulence factors of Salmonella?

Flagella (for motility), LPS (endotoxin), Type III secretion systems (for injecting effector proteins into host cells), and Vi antigen (S. typhi, for capsule production).

What are the key virulence factors of Shigella?

Shiga toxin (inhibits protein synthesis), Type III secretion system (for invading host cells), and Ipa proteins (for invasion).

What are the key virulence factors of Yersinia pestis?

Pla protease (plasminogen activator, aids dissemination), Yersinia outer proteins (YOPs, for immune evasion), F1 capsular antigen (antiphagocytic), and LPS (endotoxin).

What are the key virulence factors of Klebsiella pneumoniae?

Polysaccharide capsule (K antigen, antiphagocytic and contributes to mucoid sputum), LPS (endotoxin), Adhesins, and Urease.

What are the key virulence factors of Proteus spp.?

Urease (breaks down urea, leading to struvite stones), Flagella (for swarming motility), and Hemolysins.

What are the key virulence factors of Campylobacter?

Flagella (for motility), Cytolethal distending toxin (CDT), and Adhesins.

What are the key virulence factors of Helicobacter pylori?

Urease (neutralizes stomach acid), Vacuolating cytotoxin (VacA, induces cell vacuolation), CagA (injects into host cells), Flagella (for motility), and Adhesins.

What are the key virulence factors of Treponema pallidum?

Outer membrane proteins (as adhesins for attachment), Hyaluronidase (for tissue penetration).

What are the key virulence factors of Borrelia burgdorferi?

Outer surface proteins (OspA, OspC for attachment and immune evasion), and Flagella (for motility).

What are the key virulence factors of Brucella spp.?

LPS (endotoxin), Type IV secretion system (for intracellular survival), and ability to survive and replicate within host phagocytes.

What are the key virulence factors of Mycoplasma pneumoniae?

P1 adhesin (for attachment to respiratory epithelium), and CARDS toxin (Community Acquired Respiratory Distress Syndrome toxin).

What are the key virulence factors of Chlamydia trachomatis?

Obligate intracellular growth (evades immune system), Type III secretion system (for host cell manipulation), and MOMP (Major Outer Membrane Protein).

What are the key virulence factors of Rickettsiae?

Obligate intracellular growth (evades immune system), Phospholipase D (enables escape from phagosome), and O