Haemophilus and Bordetella (and Aggregatibacter)

Question 1

Obj. 1: Describe the genus characteristics of Haemophilus.

Answer 1

1. Very tiny GNR (often appear coccobacillary)
   *Can be long, filamentous, pleomorphic in CSF
2. Very fastidious
   *Sensitive to drying and disinfectants (requires prompt transportation and
   processing)
3. Require special growth factors (X,V, or both)
4. No growth on MAC or primary media
5. Mousy smell
6. Oxidase and Catalase positive
7. Most species are non-pathogenic (opportunistic pathogens)
8. Adapted to respiratory tract (upper)

Question 2

Obj. 2: Identify the growth requirements of Haemophilus.

Answer 2

1. Very fastidious
   *Capnophilic – requires enriched media (i.e. CHOC) and increase in CO2
2. Requires growth factors (X,V, or both)

Question 3

Obj. 3: Identify sources of X and V factors (media types, organisms, enrichments).

Answer 3

1. X factor
   *Hemin – derived from RBCs
   *SBA
2. V factor
   *NAD (nicotinamide adenine dinucleotide)
   *RBCs – contain V factor and enzyme inactivating V factor
   *Yeast extract (CHOC)
   *Produced by S. aureus, Neisseria, S. pneumoniae, etc.

Question 4

Obj. 4: Identify the species of Haemophilus using X and V factor requirements and Rabbit blood hemolysis.

Answer 4

1. H. influenzae:
   *Requirements: X and V
   *Rabbit blood hemolysis: No
2. H. parainfluenzae:
   *Requirements: V
   *Rabbit blood hemolysis: No
3. H. haemolyticus:
   *Requirements: X and V
   *Rabbit blood hemolysis: Yes
4. H. parahaemolyticus:
   *Requirements: V
   *Rabbit blood hemolysis: Yes

Question 5

Obj. 17: Discuss the symptoms that are typical in women with bacterial vaginosis.

Answer 5

1. Strong fish-like odor
2. Pain, itching, burning in the vagina
3. A thin white/gray vaginal discharge

Question 6

Obj. 18: Outline the procedures recommended for diagnosis of bacterial vaginosis.

Answer 6

1. Direct exam for “Clue Cells”
2. SPS (sodium polyanethol sulfonate) susceptibility test – BV inhibited
3. S. pneumoniae inhibition

Question 7

Obj. 19: Describe the appearance of clue cells on wet prep or Gram stained direct smears.

Answer 7

Squamous epithelial cell “plastered” with bacterial rods (in a gram stain, these are gram variable rods)

Question 8

Obj. 9: Describe the differences between the genera Haemophilus and Bordetella.

Answer 8

1. Non invasive (rarely positive blood cultures)
2. Does not require X or V factors

Question 9

Obj. 10: List the growth requirements for Bordetella.

Answer 9

1. B. pertussis secretes fatty acids that inhibits its growth – charcoal/increased
   blood in medium required for growth
   *Bordet-Gengou
   *Charcoal Cephalexin
   *Regan-Lowe Agar
2. Incubate seven (7) days

Question 10

Obj.11: Identify the recommended procedures for specimen collection, primary isolation and identification of B. pertussis.

Answer 10

1. Nasopharyngeal collection w/ calcium alginate or Dacron swab
2. Primary isolation requires a charcoal/increased blood media (see Obj. 10 for
   specific types)
3. Culture and PCR is ideal

Question 11

Obj. 12: Differentiate between the classic stages of pertussis (catarrhal, paroxysmal and convalescent) including symptoms, duration and best times for culture.

Answer 11

Catarrhal:
*Symptoms: runny nose, malaise, fever, sneezing (common cold symptoms)
*Duration: 1-2 weeks
*Culture recovery: highest bacterial load – best time to recover bacteria

Paroxysmal:
*Symptoms: repetitive cough w/ whoops, vomiting, leukocytosis
*Duration: 2-4 weeks
*Culture recovery: bacterial load decreasing – less likely to recover bacteria

Convalescent:
*Symptoms: diminished cough, development of secondary complications
*Duration: 3-4 weeks (or longer)
*Culture recovery: bacteria load relatively non-existent – very unlikely to recover
bacteria

Question 12

Obj. 13: Identify one major identifying laboratory characteristic for B. parapertussis and one for B. bronchiseptica.

Answer 12

B. parapertussis: brown pigment
B. bronchiseptica: rapid positive urease result (as in an almost “immediately result upon dispensing of reagent)

Question 13

Obj. 14: Recognize the causative agent of kennel cough.

Answer 13

B. bronchiseptica

Question 14

Obj. 15: Identify the patient populations that are most susceptible to infections with Haemophilus and Bordetella.

Answer 14

Haemophilus: infants and young children (typically < 6 y.o.)
Bordetella: infants, due to not being fully vaccinated (typically by 6 y.o.)
adults, due to waning immunity (booster needed every 7-10 yrs.)

Question 15

Obj. 16: Discuss why there has been an increase in pertussis cases, in spite of early vaccination.

Answer 15

Waning immunity against B. pertussis – for adults, a booster every 10 yrs is recommended to maintain good immunity