HACEK GROUP and Other Gram Negative Bacilli

Question 1

HACEK GROUP

Answer 1

Haemophilus
Aggregatibacter actinomycetemcomitans
Cardiobacterium hominis
Eikenella corrodens
Kingella spp

Question 2

• Amongst all of the organisms, this is the only capnophilic, the rest are dysgonic
• Common Infection:
• Normal biota / flora of the oral cavity
• Type of organisms

Answer 2

• Cardiobacterium hominis
• Endocarditis
• ACEK
• Opportunistic organisms

Question 3

● Derived from the Greek word meaning “blood-lover”
● Fastidious bacteria

Answer 3

HAEMOPHILUS SPP.

Question 4

HAEMOPHILUS SPP.

Requirements:

Answer 4

X factor, V factor

Question 5

● V factor dependent Haemophilus spp. growth (-); RBC are still intact and contains NADase (hydrolyze V factor)
● Lysing of the red blood cells by heat; releases both the X factor and the V factor; Inactivates NADases

Answer 5

• BAP
• CAP

Question 6

Phenomenon which helps in the recognition of Haemophilus spp. that require V factor occurs when S. aureus, S. pneumoniae, or Neisseria spp. produce V factor

Answer 6

Satellitism

Question 7

○ Organisms:
○ BAP:
○ Culture the organism beside?

Answer 7

source of V factor
source of X factor
S. aureus, S. pneumoniae, or Neisseria spp.

Question 8

• Also called as “Pfieffer’s bacillus”
• plays the most significant role
• Antiphagocytic property and anticomplementary activity
• Serologic groups:
• Most invasive:
• The capsule is composed of

Answer 8

• Haemophilus influenzae
• Capsular polysaccharide
• Capsule
• a, b, c, d, e & f
• serotype b (Hib)
• ribose, ribitol, and phosphate (polyribitol phosphate)

Question 9

Only genus that produces IgA protease:

Answer 9

H. influenzae

Question 10

Adherence Mechanisms of H. influenzae
* adherent to human epithelial cells
* a serotype not adherent to human epithelial cells; systemic infections

Answer 10

• NTHi
• Serotype B

Question 11

• Also called as “Koch-Weeks bacillus” May be mistaken as Mycobacterium tuberculosis
• Conjunctivitis in Pediatric Patients
• “smallest pathogenic bacteria”; Not part of our normal flora
• Gram stain appearance: school of fish, railroad track, fingerprint

Answer 11

HAEMOPHILUS AEGYPTIUS
HAEMOPHILUS INFLUENZAE BIOGROUP AEGYPTIUS
HAEMOPHILUS DUCREYI
HAEMOPHILUS DUCREYI

Question 12

• HAEMOPHILUS AEGYPTIUS causes?
• HAEMOPHILUS INFLUENZAE BIOGROUP AEGYPTIUS causes?
• HAEMOPHILUS DUCREYI causes?
• HAEMOPHILUS PARAINFLUENZAE causes?

Answer 12

• Acute conjunctivitis “sore eyes” or pink eyes
• Brazilian Purpuric Fever (BPF)
• Chancroid (soft); Suppurative, enlarged, draining,
• inguinal lymph nodes (buboes) (similar to yersinia)
• Endocarditis

Question 13

• H. influenzae
• H. parainfluenzae
• H. haemolyticus
• H. parahaemolyticus
• H. aegyptius
• H. aphrophilus
• H. paraphrophilus
• H.ducreyi

X factor, V factor, Beta Hemo, D-ALA

Answer 13

• X, V
• V, D-ALA
• D-ALA (-)
• X factor (-)
• X, V
• D-ALA (+)
• V, D-ALA (+)
• X (+)

Question 14

• Odor of haemophilus influenzae
• Pattern of parahaemolyticus and haemolyticus
• Non-encapsulated morphology

Answer 14

Mousy odor
B-hemolytic pattern
Haemophilus influenzae biogroup aegyptius

Question 15

Culture of Haemolyticus

• H. influenzae: With 300 ml/L bacitracin; excellent medium for the isolation of Haemophilus spp. For RT specimens
• H. ducreyi & H. aegyptius
• H. ducreyi (grows best at 33C)

Answer 15

• CAP incubated between 33° C & 37° C with 5% to 10% CO2 at 18-24 hrs of incubation
• CAP with 1% IsoVitaleX or Vitox
• Nairobi biplate (GC agar base with 2% bovine hemoglobin and 5% fetal calf serum w/ vancomycin & Mueller Hinton agar with 5% chocolatized horse blood
  w/ vancomycin)

Question 16

Reagent of porphyrin test
Result: presence of porphobilinogen
Result: presence of porphyrins

Answer 16

• p-dimethylaminobenzaldehyde (Kovac’s reagent)
• Red color in lower aqueous phase
• Reddish orange fluorescence in UVL detection at 360 nm

Question 16

• Alternative method for differentiating the heme-producing species of Haemophilus
• Principle: based on the ability of the organism to convert the substrate δ-aminolevulinic acid (ALA) into porphyrins or porphobilinogen (intermediates in synthesis of X factor)

Answer 16

Porphyrin test

Question 17

Colonial mophology:

• Do not grow in MAC, CAP: “mousy” or bleach like color
• CAP: tannish and drier with a medium to large size compared with H. influenza
• CAP: small, flat, smooth, nonmucoid, transparent to opaque colonies
• BAP with Horse or rabbit blood: nonhemolytic
• BAP with Horse or rabbit blood: betahmolytic

Answer 17

• H. influenzae
• H. parainfluenzae
• H. ducreyi
• H. influenzae
• H. parahaemolyticus

Question 18

This organism is derived from the greak word means foam-loving or desires high concentration of CO2 even though it does not require it
Also known as H. aphrophilus and H. paraphrophilus

Answer 18

Aggretibacter aprophilus

Question 19

• “Star shape with four to six points” in the center of the colonies after 48 hours of incubation when cultured in BAP

Answer 19

Aggretibacter actinomycetans

Question 20

Aggretibacter spp.

Catalase, carbohydrates, urease

A. aprophilus
A. actinomycetecomitans

Answer 20

both negative
glucose, maltose, sucrose, lactose / glucose
+ / -

Question 21

Form rosettes or sticklike structures in yeast extrac

Answer 21

Cardiobacterium hominis

Question 22

Cardiobacterium hominis

Results
* MAC
* Agar
* Catalase
* Indole
* Oxidase

Answer 22

• • negative
• presence of pitting
• • nega
• • posi
• +

Question 23

Commonly associated with “clenched fist wounds” or after the skin has been broken by human teeth ○ Bacteria will be inoculated in the
wound and will result in an infected clenched fist wound.

Answer 23

EIKENELLA CORRODENS

Question 24

# Eikenella corrrodens * Agar * Odor * Catalase * Oxidase * Ornithin

Answer 24

* Pitting * Chlorine-bleach like * - * + * +

Question 25

# Kingella spp * Motility * Morphology * Catalase * Oxidase * Utilize

Answer 25

* Twitching * Cocco bacillary with squared ends in pairs or short chains * - * + * Glucose and Maltose

Question 26

* Flavobacteriaceae * Normal microbiota of the oral cavity of humans like HACEK * Fastidious, facultative anaerobe, gram (-) * Fusiform bacilli (pointed/tapered ends)

Answer 26

Capnocytophaga

Question 27

# CAPNOCYTOPHAGA SPP. * Lab results * Requires * Motility * Ferments * Reduces * Oxidase * Catalase

Answer 27

* Septicemia with neutropenia * Increased CO2 * Gliding movement * suc, glu, mal, lac * nitrates and hydrolyze esculin * - * -