Gram-Negative Bacteria Flashcards

Flashcards covering key aspects of Gram-Negative Bacteria discussed in the lecture, including characteristics, pathogenesis, and diseases.

Gram-negative bacteria

A large group of human pathogens characterized by Lipid A (endotoxin)

Neisseria meningitidis

Pairs of cocci that can cause meningitis and are transmitted through respiratory droplets

Neisseria meningitidis pathogenesis

Evades phagocytosis through its capsule, uses fimbriae for adhesion, and produces secretory IgA protease

Neisseria meningitidis Meningitis Onset

May be rapid and can lead to septicemia and hemorrhagic lesions

Neisseria gonorrhoeae

Pairs of cocci, sexually transmitted, and on the CDC's URGENT list

Neisseria gonorrhoeae pathogenesis

Evades phagocytosis, uses fimbriae for attachment, and produces secretory IgA protease

N. gonorrhoeae infections in infants

Can lead to blindness in infants if infected during delivery; prevented with topical antibiotics

One treatment option for Gonorrhea

Injected ceftriaxone + oral azithromycin

Enterobacteriaceae

A family of bacteria that includes Escherichia and Klebsiella, often causing UTIs and bacteremia

Carbapenem-Resistant Enterobacteriaceae (CRE)

Antibiotic-resistant Enterobacteriaceae associated with higher mortality rates

Coliforms Morphology

Rods that are normal microbiota of the GI tract and can cause UTIs

Escherichia coli Virulent strains

Can cause UTIs, meningitis (in neonates), and gastroenteritis through exotoxins

Pathogenic E. coli

UPEC (Uropathogenic E. coli), ETEC (Enterotoxigenic E. coli), and EHEC (Enterohemorrhagic E. coli)

Uropathogenic E. coli Virulence

Fimbriae

Treatment for E. coli Gastroenteritis

Supportive care (fluids & electrolytes); antibiotics & anti-diarrheal medication often counter-indicated

EHEC

E. coli O157:H7 produces Shiga-like toxin

Proteus mirabilis & Proteus vulgaris Morphology

Rods that are Urease +

Proteus pathogenesis

Opportunistic and forms biofilms, especially with long-term urinary catheters

Urease increasing pH

Leads to infection-induced kidney stones by raising pH and causing salts to precipitate

Pseudomonas aeruginosa Morphology

Rods that are opportunistic, antibiotic-resistant, and cause 10% of HAIs

Pseudomonas aeruginosa Invasive Diseases

Burn infections, wound infections, and lung infections in Cystic Fibrosis patients

Type III Secretion System

Allows pathogen to inject virulence factors directly into host cells

Salmonella enteritidis (non-typhoid) Morphology

Rods that is an Intracellular pathogen. Normal microbiota of poultry & reptiles

Salmonella enteritidis (typhoid) Morphology

Rods that is an Intracellular pathogen. Humans are only host and the Gall bladder is reservoir in human carriers

Typhoid Salmonella Symptoms

High fever, rash, muscle aches, and alternating constipation and diarrhea

Typhoid Fever Prevention

Sanitation and Vaccine -- Provides temporary protection

Shigella Morphology

Rods that is an Intracellular pathogen and needs as few as 10 bacterial cells can make you sick!

Shigella pathogenesis Virulence

Causes actin polymerization and produces toxins

Yersinia pestis Morphology

Rods that transmitted through Biological vector à fleas and uses Respiratory droplets

Bubonic plague

Grossly swollen lymph nodes

Pneumonic plague

Bloody cough, acute respiratory distress

Bordetella pertussis Morphology

Rods that target respiratory epithelial cells and is transmitted through Respiratory droplets

Pertussis toxin: major toxin that increases mucous production

Increases mucous production and inhibits lymphocyte migration

Pertussis Symptoms

Prolonged spasmodic coughing

Legionella pneumophila

Aerosols from water sources and Replication in macrophages

Legionnaire’s Disease

Type of pneumonia