MICRO: - BACILLI (FASTIDIOUS GNB)

Question 1

Why are the fastidious species termed fastidious?

Answer 1

They have complex or specific nutritional requirements

• require increased carbon dioxide environment
• Special nutrients/ growth factors

Question 2

When testing for the presence of a fastidious organism, relying on culture alone is not effective because…

Answer 2

negative culture results may be false negative

Question 3

Other options to use other then culture to test for presence of fastidious organism?

Answer 3

serology, molecular tests

Question 4

Shape of fastidious species

Answer 4

coccoid or coccobacilli

Question 5

The smallest of all gram negative bacterias?

Answer 5

Fastidous GNB

Question 6

Why using a microscope on fastidious species may not be appropriate?

Answer 6

Fastidious species fail to discolourise completely on the gram stain, they faintly stain

Question 7

Fastidous GNB are________signaling that they vary in size/shape/ staining

Answer 7

pleomorphic

Question 9

The five fastidious GNB species

Answer 9

-Haemophilus Influenzae
- HACEK organisms
-Pasteurella species
-Bordetella Pertussis
-Legionella spp
-Capnocytophaga spp.

Question 10

The name Haemphilus influenza tells us the bacteria is_______

Answer 10

Blood loving

Question 11

A small, pleomorphic coccobacilli or rods species____

Answer 11

Haemophilus influenzae

Question 12

Part of the normal flora of upper respiratory tract in most adults and rarely cause disease

Answer 12

Haemophilus influenza

Question 13

Hemophilus influenza species associated with humans

Answer 13

• H influenzae
• H ducreyi

Question 14

how is haemophilus influenza spreads?

Answer 14

-Through direct contact
- respiratory secretions/droplets

(note: Does not cause influenza flu)

Question 15

Major virulence factor of H. Influenzae

Answer 15

Polysaccharide Capsule

Question 15

Important sources of dissemination for H influenzae?

Answer 15

-families
- and daycare centres

Question 16

Other important virulence factors of H influenzae?

Answer 16

• Fimbriae
  -Immunoglubulin A protease
• Outer membrane proteins and lipopolysaccharide

Question 17

Which H influenzae strains cause most invasive infection?

Answer 17

The encapsulated strains (Type B)

Question 17

Most common invasive disease from haemophilus influenza encapsulated strains?

Answer 17

meningitis

(Pneumonia and bacteremia occur in older children and adult with underlying disease)

Question 18

Invasive diseases from encapsulated H. Influenza strains?

Answer 18

Septicemia, meningitis, arthritis, epiglottitis, pneumonia

Question 19

T/F: Non-encapsulated H. Influenza cause invasive disease only on immunocompromised patients.

Answer 19

True

Question 20

Non-invasive diseases from non-encapsulated H influenza strains?

Answer 20

otitis media, sinusitis, conjuctivitis

Question 21

H. Influenza growth requirements as it’s one of the fastidious spp?

Answer 21

Requires growth factors present in RBCs.

X factor (unknown factor)- hemin or hematin
V factor (vitamin)- NAD

• H influenza requires chocolate agar for recovery of the species from clinical specimens
• Grow better in CO2

Question 22

Require environment rich in CO for optimum growth

Answer 22

-HACEK org

Question 23

Fastidious species forming part of normal human flora of oral cavity

Answer 23

HACEK org

Question 24

HACEK are non-invasive oral flora org. Two ill practices can introduce these organisms into your blood stream. These are_____and _____

Answer 24

- Poor dental hygiene - Oral surgery

Question 25

T/F: HACEK can cause opportunistic infections on the immunocompromised

Answer 25

True

Question 26

The pleomorphic GNB with pibolar staining( ends of the bacilli stain more intensely than the middle).

Answer 26

Pasteurella species

Question 27

A fastidious GNB requiring high CO2 , with some species requiring a V factor

Answer 27

Pasteurella species

Question 28

The most common Pasteurella species causing disease in human?

Answer 28

Pasteurella multocida

Question 29

Where is the Pasteurella multocida found on living organisms? Like its habitat

Answer 29

-Mouth /GI and Respiratory tract of healthy animals (esp cats, dogs, horses, cattle etc)

Question 30

How are human infected with Pasteurella multocida?

Answer 30

Through animal bites - Humans present with skin/soft tissue infection following animal bites.

Question 31

Upon animal bites and infection with Pasteurella multocida. The infection can rarely cause______

Answer 31

-Lung abscesses, empyema, septicaemia...

Question 32

Also a tiny gram negative coccobacilli

Answer 32

Bordatella pertussis

Question 33

How is Bordatella Pertusis transmitted?

Answer 33

Inhalation of highly infectious respiratory droplets---the disesase then colonises the respiratory mucosa

Question 34

Outcome from infection with Bordatella pertusis

Answer 34

-Damaged ciliated epithelium from bacterial toxins -Whooping cough

Question 35

Preferrable daignoses of bordatella pertusis?

Answer 35

PCR

Question 36

Preventative strategy of bordatella pertusis

Answer 36

Vaccine

Question 37

Fastidious GNB which lives in aquatic bodies- rivers, streams, air conditioner, water coolers?

Answer 37

Legionella spp. (L. Pneumophilia)

Question 38

Mode of transmission of legionella spp?

Answer 38

Inhalation of contaminated aerosol

Question 39

A fastidious spp which causes pontiac fever, legionnaires disease, a rapidly progressive pneumonia?

Answer 39

Legonella spp

Question 40

fastidious species requiring specialised media containing iron and cysteine? The species is slow growing

Answer 40

Legionella spp

Question 41

Diagnoses of Legionella is through?

Answer 41

Molecular identification methods: PCR

Question 42

Majority of this species are part of the normal flora of human oral cavity?

Answer 42

Capcytophaga spp

Question 43

Thin, spindle shaped GNB with pointed ends, requiring increased CO2 for growth?

Answer 43

Capnocytophaga

Question 44

Can cause the sever illness in individuals with asplenia; And Septicaemia in neutropenic patients

Answer 44

encapsulated capnocytophaga

Question 45

Source of oral ulcers?

Answer 45

capnocytophaga spp