Bacteriology-43 Haemophilus, Moraxella, And Bordetella Infections*

Front 1

What are the basic characterisitics of Haemophilus, Moraxella, and Bordetella

Back 1

Small gram negative coccobacilli
Usually require rich media (often blood or its derivatives) for growth

Front 2

What major diseases are caused by Haemophilus, Moraxella, and Bordetella

Back 2

Meningitis (Haemophilus influenzae type B)
Epiglottitis (H. influenzae type B)
Cellulitis (H. influenzae type B)
Pneumonia (H influenzae type B, Moraxella catarrhalis)
Chronic otitis media (Moraxella catarrhalis)
Acute otitis media (H. influenzae non-encapsulated)
Sinusitis (H. influenzae non-encapsulated)
Conjunctivis (H. influenzae non-encapsulated
Chancroid or soft chancre (H. ducreyi)
Whooping cough or pertussis (Bordetella pertussis)

Front 3

In the 1980s, what was the number one cause of bacterial meningitis in children 6 months-5 years

Back 3

Haemophilus influenzae. Has decreased because of vaccination

Front 4

What are the characteristics of Haemophilus

Back 4

Gram negative coccobacilli (curved ends on short rods)
Can be pleomorphic, can appear gram variable
Non-motile, non-spore forming
Fastidious, requires X (hemin, heat stable) or V (can be replaced by NAD or NADP, heat labile) or both (provided on chocolate agar)
Grows best in 5-10% CO2

Front 5

What are the antigens of Haemophilus influenzae

Back 5

Six capsular types, a-f. Strains responsible for systemic disease are primarily capsular type b. Can by typed by Quellung reaction or immunofluorescence
Type b is polyribose-ribitol phosphate (PRP)
Antiphagocytic
Antibody protective against invasive infections
Non-encapsulated forms are normal flora in the URT. Often isolated in otitis media

Front 6

What diseases are caused by typically type B Haemophilus influenzae infections

Back 6

Meningitis- unvaccinated toddlers
Epiglottitis- obstructive, cherry red epiglottis, life threatening in unvaccinated children
Pneumonia often complicated by empyema. Seen in adults with COPD
Bacteremia, cellulitis, septic arthritis

Front 7

What diseases are caused by nontypeable (non encapsulated) Haemophilus influenzae

Back 7

Acute otitis media, sinusitis- second only to Streptococcus pneumoniae, may follow viral infection
Exacerbations of COPD
Community Acquired Pneumonia
Acute respiratory tract infections in 3rd world children
Conjunctivitis- outbreaks in daycares
Neonatal and maternal sepsis- biotype 4
Bacteremia and invasive infections- in adults with underlying conditions

Front 8

What does meningitis usually result from in Haemophilus influenzae infection

Back 8

Hematogenous spread rather than direct penetration of the CNS

Front 9

What can predispose to Otitis media or bacteremia caused by Haemophilus influenzae

Back 9

Prior nasopharyngeal infection with influenza virus

Front 10

Following bloodstream invasion by Haemophilus influenzae type b, the occurrence of meningitis correlates strikingly with what

Back 10

The duration and intensity of the bacteremia. Increased incidence of bacteremia in those without proper spleens. Reduced bacteremia incidence after prior administration of specific anti-capsular antibodies or after priming with cross-reactive E.coli

Front 11

For lab diagnosis, where can specimens of Haemophilus influenzae be obtained

Back 11

Depends on the disease-- CSF, blood, joint aspirate

Front 12

How is Haemophilus isolated and identified in the lab

Back 12

Gram stain CSF (careful interpretation)
5-10% CO2
Latex agglutination reaction for type b capsule

Front 13

What immune function is important for protection against Haemophilus influenzae

Back 13

Phagocytosis. Anti-capsular antibodies act as opsonins that mediate complement-dependent phagocytosis of the organisms. Antibodies plus complement can also lead to bacterial lysis

Front 14

Why is it important to vaccinate children between 2 months and 3 years against Haemophilus influenzae

Back 14

Their antibody titers are minimal, and disease incidence is high

Front 15

How is Haemophilus influenzae treated

Back 15

3rd generation Cephalosporin, or ampicillin if susceptible. Childhood meningitis is often treated with both

Front 16

How is Haemophilus influenzae infection prevented

Back 16

Several different Hib-conjugate vaccines (Hib coupled with diphtheria toxoid)
Rifampin is given to unvaccinated house-hold contacts of Haemophilus influenzae type b-infected young children

Front 17

Besides Haemophilus influenzae, what are some other types of Haemophilus

Back 17

H. parainfluenzae- normal URT, 10% in saliva
H. aphrophilus- normal on tooth surfaces; can cause endocarditis or brain abcesses
H. aegyptius (Kochs-Weeks bacillus)- acute purulent conjunctivitis or pink eye (contagious)
H. influenzae biotype aegyptius type 1 causes Brazilian purpuric fever
H. ducreyi

Front 18

What are some signs and symptoms of Haemophilus ducreyi infection

Back 18

Causes chancroid or "soft chancre"
Ragged ulcer on genitalia with marked swelling and tenderness
Regional lymph nodes often large and tender
Associated with poor socioecomonic conditions
Increased numbers during wartime

Front 19

Haemophilus ducreyi specimens grow best on what

Back 19

Agar enriched with vitamins, amino acids, serum, and blood (Fildes-enriched gonococcal media) in atmosphere of 10% CO2 at 34C

Front 20

What are the characteristics of Moraxella

Back 20

Gram negative coccobacilli (can be diplococcus)
Oxidase positive
Some species require enriched media such as blood or chocolate agar to grow

Front 21

What diseases does Moraxella catarrhalis cause

Back 21

Moraxella catarrhalis is normal flora of the URT. It can cause otitis media and pneumonia, particularly in the elderly
It is penicillin resistant due to its Beta lactamase

Front 22

What is the definition of pertussis (whooping cough)

Back 22

Acute infectious disease of tracheobronchial tree with characteristic clinical picture. Etiological agent is Bordetella pertussis

Front 23

What are the characteristics of Bordetella

Back 23

Gram negative, short coccobacilli, pleomorphic, encapsulated when virulent
Requires enriched media that binds fatty acids (Bordet-Gengo Agar (BG) or charcoal agar base (CHB))

Front 24

What are the three main species of Bordetella

Back 24

B. pertussis- humans only
B. parapertussis- May cause pertussis-like disease in humans
B. bronchiseptica- dogs

Front 25

What are the main toxins and virulence factors in Bordetella

Back 25

Pertussis toxin: causes activation of membrane adenylate cyclase of eucaryotic cell via ADP-ribosylation of the Gi protein
Extracellular adenylate cyclase: Resembles EF of anthrax (calmodulin dependent). Has hemolytic activity
Filamentous hemagglutinin and pertactin: adhesive factors
Tracheal cytotoxin: Destroys ciliated epithelial cells. Resembles a fragment of the cell wall

Front 26

What are the proposed steps in pathogenesis of Bordetella

Back 26

Colonization without invasion of ciliated bronchial epithelia via filamentous hemagglutinin and pertactin
Localized damage with tracheal cytotoxin
Impaired host immune response due to extracellular adenylate cyclase (hemolysin)
Systemic effects due to pertussis toxin

Front 27

What is the epidemiology of Bordetella?
What are the stages of infection?

Back 27

Primarily affects unvaccinated kids under 4
Very contagious
Incubation 7-10 days
Three stages: Catarrhal (common cold); Paroxysmal (violent coughing); Convalescent (persistent cough)

Front 28

How might adolescents and adults whose natural or acquired immune response to Bordetella pertussis has waned present upon infection

Back 28

With a long-standing cough (without a whoop)

Front 29

How is pertussis treated

Back 29

Just treat the symptoms (may use corticosteroids). Can use erythromycin for the unimmunized

Front 30

What is the pertussis (aP) vaccine

Back 30

A mixture of purified, inactivated Bordetella pertussis products