Haemophilus 2 Flashcards
Specimen collection issues concerning B.pertussis
B. pertussis: specimens must be collected from the nasal passage (not throat, sputum or anterior nose); specimen should be immediately inoculated onto selective media (or placed into transport media)
Microscopy concerns of Legionella
(Gram stain and/or Fluorescent Antibody)
• Legionella may not be detectable in initial specimen smears due to their poor staining
Antigen concerns of Legionella
Rapid detection of Legionella antigen in urine by enzyme immunoassay
- Gram-negative pleomorphic coccobacilli/rods
- Facultative anaerobes
- Most species are non-pathogenic
- Require preformed growth factors present in the blood for growth:
General characteristics of Haemophilus
Growth factors : X factor (hemin) and/or V factor (nicotinamide-adenine dinucleotide – NAD)
- Normal flora of the respiratory tract (exception)
- Person to person and endogenous (exception)
- Capsule, Pili, surface factors
Habitat and Epidemiology(transmission/Virulence factors) of Haemophilus
Exceptions : H. ducreyi only found in humans during infection, and transmitted via sexual contact
Clinical significance of Haemophilus species :
H. influenzae, ducreyi, aegyptius
HI - pneumonia; meningitis; epiglottitis; otitis; sinusitis
HD - Chancroid
HA - Conjuntivitis
- Gram-negative coccobacilli
- Fastidious; grow best in increased CO2
- Normal flora of the oral cavity of humans
- Mode of transmission: many endogenous
General characteristics of HACEK
- Small, gram-negative bacilli
- Nasopharynx and gastrointestinal tract of wild and domestic animals
- Transmitted by animal bite/scratch infects soft tissue and blood
- Capsule
General characteristics of Pasteurella
Strict aerobe
• Very small, gram-negative coccobacilli/rods
• Four species
General characteristics of Brucella
• Acute: symptoms appear in 1 to 3 weeks post exposure
• Malaise, chills, sweats, fatigue, weakness, myalgia, weight loss,
nonproductive cough
• Chronic/relapse can occur 3 to 6 months post therapy
Brucellosis
- Strict aerobe
- Faintly staining, gram-negative coccobacilli
- Carried by wild rodents, rabbits, beavers, ticks
General Characteristics of Francisella
Ulceroglandular/Oculoglandular/Pneumonic tularemia
UT - painful papule develops at site of inoculation and progresses to ulcer
OT - Following inoculation into eye; painful conjunctivitis
PT - Pneumonitis with signs of sepsis develops rapidly after exposure to contaminated aerosols; high mortality
• Strict aerobes
• Require L-cysteine for primary isolation
• Pleomorphic, weekly staining gram-negative bacilli
• Ubiquitous and widely distributed in the environment
(predominately in aquatic habitats)
Legionella general characteristics
Pontiac fever
Non-pneumonic form of legionellosis
• Self-limited, febrile illness that lasts 2 to 5 days
Legionnaire’s disease
Atypical pneumonia
• Incubation period of 2 to 10 days, acute illness
• Mortality ranges from 15 to 75%
