Fastidious/Misc Gram-Nagative Bacilli – Flashcards

Non-Motile; Gram-Negative Bacilli ranging from coccobacilli to filamentous rods; the more mature they are the more pleomorphic they are.

DO NOT GROW ON SHEEP BLOOD AGAR; only species that does this

Fastidious: require one or both of the accessory growth factors, called X Factor (Heme; heat stable) and V Factor (NAD: nicotinamide adenine dinucleotide)

Nitrate Reduction Positive

Members of indigenous microflora of oral cavity and upper respiratory tract

Acronym of the first initial of each genus that belong in the group:
Haemophilus aphrophilus

Actinobacillus actinomycetemcomitans

Cardiobacterium hominis

Eikenella corrodens - pitts the agar; smells like bleach

Kingella species

Found as indigenous microflora of the oral cavity and can cause a certain type of endocarditis

Small, Gram-Negative Bacilli or coccobacilli

One of the leading causes of meningitis, ear infections, and sinus infections.

Satellites around S. aureus and some other colonies on sheep agar

Porphyrin synthesis (δ-aminolevulinic acid test) NEGATIVE

Requires BOTH X AND V FACTORS

Grows on Chocolate agar in 5% CO₂; DOESN'T GROW ON SHEEP AGAR

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Most common Haemophilus;spp. in the indigenous microflora of the upper respiratory tract

Colonies are flat, grayish, semiopaque, and either smooth or rough and wrinkled after 24 hours incubation

X Factor Negative; Requires V Factor (Positive)

ALA - Porphryrin Test Positive

Beta-Hemolysis Negative

Indigenous microflora of the upper respiratory tract

Associated with acute purulent ; contagious form of conuuntivitis (pink eye)

Especially fastidious

Very small, smooth colonies

Requires BOTH X and V FACTORS

ALA - Porphryrin Test Variable (+/-)

Beta-Hemolysis Negative

Indigenous microflora of upper respiratory tract

Not pathogenic

REQUIRES BOTH X and V FACTORS

ALA-Porphryrin Test Negative

Beta-Hemolytic POSITIVE

Indigenous microflora of upper respiratory tract

Not pathogenic; associated with pharyngitis, lower respiratory tract infections, and oral abscesses

REQUIRES X FACTOR; V Factor Negative

ALA-Porphryrin Test Positive

Strongly Hemolytic; large zones of hemolysis

Long, slender Gram-Negative bacillus

Microflora of oral cavity (found in dental plaque), blood and Meninges

Associated with brain abscesses, postoperative infections, arthritis

Rough, raised colonies rarely exceeding 1 mm in diameter

REQUIRES NEITHER X and/or V FACTORS

ALA-Porphryrin Test Positive

Beta-Hemolysis Negative

Causes CHANCROID a sexually transmitted disease in Asia, Africa, Latin America

Especially Fastidious

Grows best at 33;C

Produces long parallel rows of small bacilli in chains; school of fish, railroad track or fingerprint appearance)

Smooth, semitranslucent, gray

Cohesive colonies can be pushed across the agar

REQUIRES X FACTOR; V Factor Negative

ALA-Porphryrin Test Negative

Beta-Hemolysis Negative

Gram-Negative bacilli

Require an increased CO₂;environment (5-10%)

Flora of oral cavity; significant cause of endocarditis; opportunists in immunocompromised patients

Colonies have irregular edges and finger-like projections (gliding or sliding motility) that appear as a thin film surrounding the central part of the colony.

Colonies may have a moist, mottled, or "sweaty" appearance

Colonies adhere to agar surface and most are non-hemolytic

Catalase Negative

Oxidase Negative

Indole Negative

Urease Negative

Produce Negative decarboxylase tests

Capnocytophaga;spp. associated with infected dog/cat bite wounds are: C. canimorsus;and C. cynodegmi;

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Oxidase Positive ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Catalase Positive

;Small Gram-Negative coccobacillus that appears singly or in pairs

Etiologic agent (cause) of whooping cough (very contagious)

Preferred Media: Bordet-Gengou and Regan-Lowe (CHB) mediums

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Colonies look like mercury droplets or partially imbedded pearls

SHOULD BE INCUBATED AT 35;c IN ROOM AIR FOR MIN. OF 7 DAYS

Catalase Positive ; ; ; ; ; ; ; ; ; ; ; ; ; ; ;Oxidase Positive

Nitrate Negative ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Urease Negative

Non-Motile ; ; ; ; ; ; ; NO GROWTH ON BAP OR MAC

Erythromycin = drug of choice for treatment ; prophylaxis of pertussis

General Characteristics:

Colonizes mucous membranes of the upper respiratory tract and gastrointestinal tracts of mammals or birds

Human infections occur from bites and scratches infected by animals (mostly dog and cat bites

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Penicillin is the drug of choice for treating Pasteurella;infections ; ; ;;Most common isolated species is Pasteurella multocida

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Blood/Chocolate Agar: small, smooth, convex colonies; "Musty Odor"

May be mucoid and watery when isolated from respiratory secretions

NO GROWTH ON MAC

Very small, Gram-Negative Rods with "safety pin" (bipolar) appearance

Bipolar staining with Giemsa or methylene blue

Oxidase Positive ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Catalase Positive

Indole Positive ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; Ferments Glucose

Quick screening is their penicillin susceptibility (unusual for GNB)

Gram-Negative Rods found, appearing, or present everywhere

Fastidious, aerobic bacteria:

* Unable to grow on blood agar and require the amino acid L-cysteine for growth.

Buffered Charcoal Yeast Extract (BCYE) = preferred agar

Acquired through inhalations of aerosols by humans

Febrile disease w/pneumonia (Legionnaire's disease) and extrapulmonary involvement

Pontiac Fever (without pulmonary involvement)

Asymptomatic infection

L. pneumophilia = the species most commonly associated with human disease

Motile, faintly staining Gram-Negative Bacilli; range in appearance from small coccobacilli to long filaments

One of the etiologic agents (causes) of legionellosis (Legionnaires disease)

Requires cysteine for in vitro growth

Will grow on Chocolate Agar; will not grow on standard culture media

Buffered Charcoal Yeast Extract (BCYE) is primary agar medium used; usually supplemented with α-ketoglutarate, L-cysteine, and ferric pyrophosphate

Colonies are whitish green

3 Rapid methods for identifying Legionella isolates approved by FDA:

* Direct fluorescent antibody (DFA)

* DNA detection

*Urine antigen Testing

Usual basis for Identification Include:

1) cellular morphology (thin, weakly staining Gram-Negative bacilli or filaments)

2) their requirement for cysteine

3) their non-fermentative metabolism

4) serotyping by slide agglutination or direct fluorescent antibody stain

Tiny, faintly staining Gram-Negative coccobacilli

Non-Motile

Etiologic agent (cause) of tularemia (aka: tick fever, deerfly fever, and rabbit fever) Hunters especially with contact w/infected animals

Potential bioterrorism land biological warfare agent

Grows poorly, if at all, on ordinary media

Optimal growth with: media supplemented with sulfhydral compounds, such as cysteine, cystine, thio-sulfate, and Iso Vitalex

Causes acute febrile granulomatous disease with rapid onset and flu-like symptoms