WEEK 15: HAEMOPHILUS AND OTHER FASTIDIOUS Flashcards
i. Nonmotile and facultative anaerobic
ii. Ferment Carbohydrates (Except for H. ducreyi)
iii. Oxidase and Catalase Positive
iv. Reduce Nitrates to nitrite
vi. Obligate parasites
vii. Requires growth factors
▪ Hemin/hematin (X Factor)
▪ Nicotinamide adenine dinucleotide (NAD or V Factor)
Haemophilus
What are the required growth factors for Haemophilus?
▪ Hemin/hematin (X Factor)
▪ Nicotinamide adenine dinucleotide (NAD or V Factor)
It is also called Pfeiffer’s bacillus.
Haemophilus influenzae
Lacks adherent capability; associated with systemic and invasive infections
Encapsulated
Associated with localized infections or may be carried asymptomatically (nasopharynx).
Non encapsulated
- “Koch-Weeks bacillus”
- Purulent conjunctivitis “pink eye”
Haemophilus aegyptius
What is the organism that causes chancroid (genital diseases)?
Haemophilus ducreyi
▪ Small, flat, smooth, transparent to opaque
▪ Colonies can be pushed intact
▪ Clumpy in saline
H. ducreyi
BPF (Brazilian Purpuric fever)- skin lesion, sepsis, fever
H. influenzae Biogroup aegyptius
▪ 5% to 10% CO2 at 35°C to 37°C
▪ 24 to 72 hours
Most Haemophilus spp.
▪ 5% to 10% CO2 at 33°C with high humidity
▪ Up to 7 days
Haemophilus ducreyi
coccobacilli that appear as “school of fish”, “railroad tracks” or “finger prints” from genital lesions.
H. ducreyi
Small. Gram (-) coccobacilli
to long filaments. May be
encapsulated
Haemophilus
▪ Translucent, smooth and convex
▪ “Mousy” or bleach like odor in CHOC agar
▪ Encapsulated strains are larger and mucoid
H. influenzae
Satellite phenomenon
Staphylococcus Streak
Antisera is reacted with the antigens in the capsule making the capsule more prominent
Neufeld Reaction
Quadrant I
Hemin (X)
Quadrant II
Isovitale (V)
Quadrant III
Hemin(X) and Isovitale (V)
Quadrant IV
Horse blood (X) / NAD (V
Porphobilinogen is detected using?
Kovac’s rgt
i. Dysgonic (slower or poorer
growing)
ii. Associated to subacute bacterial endocarditis
iii. Normal biota of the oral cavity
iv. Fail to grow in MacConkey
v. Glucose fermenter
(Require serum to the
fermentative media)
vi. Opportunistic bacteria
Fastidious Gram Negative Bacilli
i. “foam loving” or needing high conc.of CO2
ii. Found in dental and gingival scrapings
iii. With V factor dependent and independent strains
iv. Gram Stain: Small Gram (-) coccobacilli
v. Colony Characteristics: Convex, granular and yellow with an opaque zone near the center
Aggregatibacter aphrophilus
- Infections
▪ Periodontitis; Local infection to fulminant infection (septicemia) esp. in neutropenic patients - Laboratory Diagnosis
i. Microscopy
▪ Thin and fusiform, spindle-shaped, coccoid and curved filaments
ii. Culture Characteristics
▪ Haze (gliding motility) on solid surface
▪ opaque, shiny; pale beige or yellowish
▪ Resemble HACEK in CO2 requirement
▪ May produce yellow pigment; can resemble colonies of E.corrodens
Capnocytophaga
- Infections
▪ Systemic, pneumonic and cutaneous infection from
animal (often cats) bites (zoonosis) - Laboratory Diagnosis
i. Microscopy
▪ Coccobacilli (ovoid, filamentous or bacilli);
Bipolar staining
ii. Culture Characteristics
▪ Grayish, non hemolytic, mucoid with narrow green
to brown halo around the colony
Pasteurella multocida
HACEK Group
- Aggregatibacter (formerly Haemophilus)
aphrophilus - Aggregatibacter (formerly Actinobacillus)
actinomycetemcomitans - Cardiobacterium hominis
- Eikenella corrodens
- Kingella spp.
i. Virulence Factor
▪ Collagenase and Leukotoxin
ii. Disease
▪ Destructive periodontitis
▪ Subacute bacterial endocarditis
iii. Other Characteristics
▪ Glucose fermenter (dysgonic); lactose & sucrose
non-fermenter
▪ Catalase (+); Urease (-) w/c differentiates it from
genus Actinobacillus
Aggregatibacter actinomycetemcomitans
i. Disease
▪ Oral Infections
▪ Subacute bacterial endocarditis
ii. Characteristics
▪ Fermenter (dysgonic); pits agar
▪ Pleomorphic gram (-) rod that tend to form rosettes or long filaments
Teardrop or arrowhead
appearance
Cardiobacterium hominisv
a. Microscopic characteristics
▪ Short bacilli in pairs /chains
▪ Bipolar staining “Morse Code” appearance.
b. Colonial appearance
▪ Pinpoint (24 hr ). With
star shape with 4 to 6 point”
in the center of the colony (48 hrs).
Aggregatibacter actinomycetemcomitans
i. Disease
▪ Infections from human bites or fights (clenched fist wounds)
▪ Cellulitis-needle use by drug addicts
▪ Oral Infections and Subacute bacterial endocarditis
ii. Characteristics
▪ Non Fermenter; Pit agar; Chlorine bleachlike odor
▪ Non-motile, oxidase positive, asaccharolytic, catalase
negative; yellow pigment
Eikenella corrodens
- Infections- zoonosis (ingestion, inhalation, arthropod bite), highly infectious
▪ Tularemia (ulceroglandular, pneumonic, etc)- rabbit
fever, water rat trappers disease - Laboratory Diagnosis
i. Microscopy
▪ Small, non-motile, coccobacili or bacilli
ii. Culture and Other Characteristics
▪ Strictly aerobic; require cysteine, cystine or thiosulfate
(SBA, BCYE agar, CHOC)
▪ Gray-white, smooth, raised colonies
▪ Biosafety Practice Level 3
Francisella tularensis
i. Disease-major gram(-) bacteria in bone infections in children below 3y.o
▪ Oral, blood, bone Infections
▪ Subacute bacterial endocarditis
ii. Characteristics
▪ Short bacilli to coccobacilli
with squared ends in pairs/in chains
▪ Fermenter (dysgonic); pits agar
▪ Nonhemolytic (K. denitrificans) or β-hemolytic (K.kingae)
Kingella spp
interferes to signal transduction
Pertussis toxin
▪ Aquatic sources (lakes, rivers, hot springs and mud)
▪ Man made distribution systems
▪ Humidifiers and respiratory therapy equipment
Legionella pneumophila
a. Enter, survive and multiply within macrophages
b. Survive and multiply within free-living protozoa
c. Multiply at 20°C to 43°C and survive at 40°C to 60°C
d. Capacity to adhere and persist in piped water systems
Legionella pneumophila
fever w/ pneumonia
Legionnaire’s disease
▪ Tiny gram-negative coccobacilli
▪ Smooth, glistening and silver, resembling mercury droplets
Bordetella pertussis and B. parapertussis
fever w/o pneumonia
Pontiac Fever
a. Isolation Methods
▪ Requires Iron and L-cysteine
▪ Chocolate agar and BCYE
▪ Ground-glass appearance
b. Colony Morphology
▪ Grayish-white or blue green, convex, and glistening
measuring 2-4 mm in diameter
▪ Characteristic “ground-glass” colony
Legionella pneumophila
facilitate attachment to ciliated epithelial cells
FHA and Pertactin
inhibits host epithelial and
immune effector cells
Adenylate cyclase toxin
▪ Bordet-Gengou potato infusion agar, Regan-Lowe, and Charcoal-horse blood
▪ Incubate at moist chamber at 35°C for ≥7 days
Bordetella pertussis and B. parapertussis
causes ciliostasis and DNA synthesis
Tracheal cytotoxin
- a-hemolytic with fruity odor similar to apples and strawberries on BAP
- grows well on Mac and motile
- grow on 6.5% NaCl broth
- oxidase and catalase positive
Alcaligenes faecalis
- colonize distal urethra and may cause serious and active infection
- cannot grow on Mac
Oligella
- water, dairy, and other environmental sources
- motile, saccharolytic and strong H2S producer
- isolated from humans with ocular infections, otitis media and septicemia
- colonies appear mucoid and greenish
- oxidase and ornithine decarboxylase positive
Shewanella putrefaciens
- angular catarrhalis
- small colonies and pits the agar
- no growth on Mac
- catalase, oxidase and nitrate reduction positive
Moraxella lacunata
