Non-Enteric Gram Negative Rods Flashcards
Respiratory Pathogens
- Haemophilus HUMANS ONLY
- Bordetella HUMANS ONLY
- Legionella ENVIRONMENT; H20
Haemophilus Influenzae
General & Growth Info
- HUMANS ONLY
Common upper respiratory tract (unencapsulated) - Fastidious: special growth requirements
- NAD & hemin; blood agar - Slender Gram - Rod with many different shapes
Haemophilus influenzae
Virulence Factors
- Capsule (type b vaccine Hib)
- IgA protease
- Iron acquisition mechanisms
Gram - Rod
Haemophilus influenzae
Clinical Manifestation
Gram - Rod
- URT, middle ear, sinuses (sinusitis), and lungs
-
Otitis Media : common childhood illness
- also found in S. Pneumonia and M. Catarrhalis - Epiglottitis: can be life threatening
- Pneumonia
- Meningitis
- Septic arthritis
Epiglottitis
Haemophilus influenzae disease; can be life threatening
IgA Protease
Haemophilus influenzae
Haemophilus influenzae
Treatment
Fairly susceptible to antibiotics; Hib conjugate vaccine
Bortadella pertussis
- HUMANS ONLY
- v. Tiny and fastidious; can only survive for short periods in environment
- colonies on blood agar
- ID via NAAT
Gram - Rod
Pertussis
- highly infectious
- 2 week incubation period
- slow convalescence (4-6 weeks)
Bordetella pertussis
Virulence Factors
Adhesins: promote attachment and prevent clearance by phagocytes
- Filamentous hemagglutinin: binds integrins on ciliated epithel. cells
- Fimbriae: phase variation
- BrkA protein: complement resistance
Toxins: pair local clearance; systemic effects
- Tracheal cytotoxin: stimulates IL-1 mediated killing of ciliated epithel. cells
- Adenylate cyclase toxin: inhibits phagocyte function
- Pertussis toxin: systemic effects
BrkA protein
Bortadella pertussis
Complement resistance
Gram - Rod
Tracheal cytotoxin
Bordetella pertussis toxin (Gram - Rod)
Stimulates IL-2 mediated killing of ciliated epithelial cells
Adenylate Cyclase Toxin
Bordetella pertussis toxin (Gram - Rod)
Inhibits phagocyte function
Pertussis toxin
Bordetella pertussis toxin (Gram - Rod)
Systemic effects
Bordetella pertussis Prevention
DTwP vaccine
Legionella pneumonphila
- ACQUIRED FROM ENVIRONMENT: H20 (aerosolized)
- Highly fastidious: BCYE agar
- buffer, charcoal, yeast extract, iron, cysteine, antibiotics
- ID via PCR NAAT
Legionella pneumophila
- ENVIRONMENTAL: warm H20 (caught when aerosolized)
- Multiplies in protozoan host
- Multiplies in machrophages
- actively blocks phagosome/lysosome function
- Control growth via hypercholrination and high heat
Zoonoses
Pathogens transmitted from animals; directly or by insect vector
- Brucella
- Paeseurella
- Francisella
- Yersinia
Zoonotic bacteria
- small Gram - Rods or Coccobacilli
- Uncommon in US
- Little to no human-human transmission
- Multiply in phagocytes
- May require “non-standard” antibiotics
- Some highly virulent
- Possible agents of bio-terrorism
Brucella app.
Type; Source; Clinical Manifestation; Threat
Small Gram - coccobacillus
Source: Livestock, unpasteurized dairy
Clinical manifestation: Systemic febrile illness; variable symptoms
Poses significant threat to laboratory workers
Pasteurella multocida
Type; Normal Flora; Clinical Manifestation; Progression Rate
Type: Small Gram - coccobacillus
Normal Flora: oral of domestic animals
Clinical Manifestation: “snuffles” in rabbits”; rapidly progressive soft tissue infec
Infection associated with animal bites (cats)
Francisella tularensis
Type; Transmission; Infectious Dose
Type: Gram - coccobacillus
Transmission: from wild animals (rabbits) by direct contact or insect bites
Highly infectious with low infectious dose required
High risk to lab workers; little human-human passing
NAAT
Francisella tularensis
Disease
- Ulceroglandular
- ulcer at site of inoculation; most common
- Oculoglandular
- eye is site of inoculation
- Oral/pharyngeal
- contaminated water
- Respiratory infection
- aerosol inhalation
Yersinia pests
Cause of bubonic plague; Black Death
Transmitted from rodents to human by flea bite
- bacteria makes flea blood clot = regurgitation of blood from prior meal = infe
