Parvobacteria, Haemophilus

Question 1

Parvobacteria characteristics :

Answer 1

gram- negative coccobacilli
Grow only in enriched media ( needs alot of nutrients ) & ( media should be enriched in nutrients in order to grow the pathogen in the lab )

Question 2

Description and morphology of haemophilus :

Answer 2

Small, non-motile, non spore-forming
Gram-negative pleomorphic bacilli (coccobacilli) depend on blood for growth (blood loving ) generic name
Most pathogenic strains are capsulated

Question 3

Growth requirements haemophilus :

Answer 3

X-factor :protoporphyrins essential for catalases, perioxidases and cytochrom of the electron transport chain
X- factor : can be supplied by heat- stable iron containing pigments like “ blood containing media”
V-factor is heat-labile, coenzyme : supplied by nicotine adenine dinucleotide (NAD or NADP)

NAD : present inside RBC

Question 4

Media of haemophilus :

Answer 4

Chocolate ager( heated blood agar)
Blood with staphylococcus aureusa (known to release NAD in media)
Nutrient media with x and v factors
5-10% co2

Question 5

Habitat of haemophilus :

Answer 5

Normal flora of upper respiratory tract

Question 6

Haemophili of medical importance include:

Answer 6

H.influenzae ( most common pathogen)
H.Parainfluenzae ( secondary pathogen, need something to facilate it)
H.aegypticus (cause eye infection)
H.ducreyi ( cause sexual disease)

Question 7

Haemophilius influenza pathogenesis:

Answer 7

1- capsul
2- six types : a, b, c, d, e, f
Most important type is B associated with invasive infections

Question 8

Virulence factor of h. Influenza:

Answer 8

Capsule
antigenic : immune cells produce protective antibodies
Direct antigen detection from clinical samples by latex agglutination using anti-capsular antibodies
Vaccine by using capsule as target

Question 9

Normal carriage of haemophilius influenza :

Answer 9

1- strict human pathogen ( cant get it from environment)
2- reside in upper respiratory tract
3- non-cabsulated carriage in nasopharynx ~ 25-80% of healthy people
4- carriage of capsulated strains ~ 5-10%

Question 10

Invasive infections because of haemophilins influenzae:

Answer 10

Usually caused by type b

Most causes ocurr in children < 2years of age

Question 11

Haemophilus influenza
Invasive infection ( most need admission to hospital)
Clinical diagnosis :

Answer 11

1-Meningitis 60%
2-Epiglottitis 15% 
3-Bacteraemia 10% 
4-Cellulitis 5% 
5-Pneumonia 5% 
6-Septic arthrits 5%

Question 12

Meningitis :

Answer 12

Most common invasive disease
droplet infection
mortaliy ~5%
neurological complications especially hearing loss~10-30%.

Question 13

Haemophilus inflenza
Non- invasive
Caused by ?

Answer 13

Non -capsulated strains
Local infections associated with underlying pathology e.g. secondary to viral infection
Typically with :
Otitis media
Sinusitis
Exacerbation of chronic obstructive pulmonary disease COPD

Question 14

Laboratory diagnosis of haemophilus infuenza :

Answer 14

1- CSF, blood, aspirate from joint, ear, sinuses 
2- Direct micriscopy 
3- Direct antigen detection 
4-Culture : grow in chocolate ager 
5-Need x & v factors

Question 15

Treatment of haemophilus influenzae :

Answer 15

Ampicillin : 25% resistance of type b
Cefotaxime & ceftriaxone : drug of first choice mainly for meningitis & other invasive diseases
Amoxacellin-clavulinic acid & azitharomycin: respiratory infections

Question 16

How to control haemophilus influenzae ?

Answer 16

Immunization 
   H.influenzae type b 
   Hib vaccine (conjugate vaccine) infants at 2,3 & r monthes

Question 17

What is chemopraphylaxis?

Answer 17

Stops transmission from people with close contant
Important for patients with haemophilus / cleans the carrying area
Chemoprophylaxis prevent infection through antibiotic

Rifampicin ( for children less than 12 years) or ciprofloxacin (for adults)

Question 18

Haemophilus species:

Answer 18

H.aegypticus : epidemic conjunctivitis
Eye disease (not invasive)
Treatment : eye drops

H.ducreyi (sexual transmitted disease)
Painful penile ulcer i.e. chancroid
Prevalent in tropical countries
Treatment is tetracyline (oral antibiotic)