Mhr Topic 19: Gram Negative Respiratory Rods

Front 1

What gram negative respiratory rod has encapsulated forms?

Back 1

H. influenzae

Front 2

Haemophilus influenzae Diagnosis (gram, capsule, culture)

Back 2

Gram negative pleomorphic rods
Infections organisms have capsule
Grown on chocolate agar

Front 3

Growth factors necessary for H. influenzae and O2 requirement

Back 3

1) Need X factor (hemin precursor), and V factor (NAD/P)
2) grow aerobically or anaerobically

Front 4

Invasive diseases caused by encapsulated H. influenzae

Back 4

1) meningitis
2) epiglottitis
3) Cellulitis
4) Osteomyelitis
5) Sepsis
6) Pneumonia
7) Septic arthritis

Front 5

Non-Invasive diseases caused by encapsulated H. influenzae

Back 5

1) Conjuncivitis
2) Sinusitis
3) Otitis media

Front 6

H. Influenzae virulence factors

Back 6

1) PRP capsule - Main, Type B capsule is necessary for invasiveness. Resists opsonization and compliment.
2) LOS - Paralyzes respiratory epithelium.
3) IgA proteases.

Front 7

H. Influenzae infection mech.

Back 7

Inhalation of infected droplets

Front 8

When does H. influenzae occur and who is at risk?

Back 8

After first 3 months (maternal Ab) and before 5 years.
Increases suseptibility for
-Ig defficient
-Sickle cell
-splenectomy
-alcoholism
-chronic pulmonary disease

Front 9

Bordetella pertussis diagnosis (gram, capsule, O2, motility)

Back 9

gram negative coccobacilli
Has capsule
Aerobic
non-motile

Front 10

B. pertussis virulence factors

Back 10

1) Pertussis toxin - AB toxin targeting lymphocytes, ^cAMP leads to secretion of fluids and electrolytes.
2) Adhesins - important for colonization of nasopharynx
3) Adenylate cyclase - inhibits phagocytosis
4) Dermonecrotic tosxin - Causes tissue necrosis via aschemia
5) Tracheal cytotoxin - damages cilli

Front 11

Bordetella pertussis disease

Back 11

Whooping cough. 3 phases:
1) Catarrhal stage - Most contagious, least recognizable. Runny nose, fever sneezing, conjunctivitis
2) Paroxysmal phase - 1-2 weeks post catarrhal. Intense coughing fits, vomiting, bloody nose, conjunctival hemmorrhage. Lymphocytocis seen (^ in blood lymphocytes). Lasts 2-6 weeks.
Convalescent stage - Can last months until resp. epithelium regenerates. 1% fatality.

Front 12

Legionella pneumophila shape and O2 preferencec

Back 12

Gram - coccobacilliary, aerobic

Front 13

Legionella pneumophila who and infection

Back 13

Adult disease. Usually elderly or immunocompromized. Acquired through inhalation of contaminated water. Often a hospital acquired infection.

Front 14

Legionella pneumophila disease

Back 14

2-10 day incubation period. 2 diseases:
1) Legionnaires disease - Mild to severe pneumonia, fever, cough
2) Pontiac fever - Milder disease with fever but without pneumonia.