Miscellaneous fastidious gram negative rods

What mode of infection are the miscellaneous gnrs assoicated with?

Zoonotic or special epidemiology

How is a pasteurella multocida infection aquired?

Cat and dog bites, normal flora for cats and dogs

What is the colony morphology of pasteurella multocida?

Smooth gray, moist with brownish/green discoloration/ halo at 48 hours on BA, also grows on CHOC

What is the gram stain of pasterurella multocida?

Gram negative coccobacilli with bipolar staining (safety pin)

What is the LAO reaction for P. multocida?

-/-/+

What are the indole and nitrate reactions for P. multocida?

Positive for both

When is P. multocida H2S positive?

With lead acetate strips

What sugars can P. multocida ferment?

Glucose, sorbitol and galactose

Is P. multocida motile?

Non-motile

Which misc gram negative rods are urease negative?

Pasturella multocida and Francisella tularensis

What is the causative agent of tularemia?

Francisella tularensis

What is tularemia also known as?

Rabbit fever, deerfly fever, lemming fever

How is tularemia aqquired?

• ingestion, inhalation, arthropod bites, contact with infected tissue

• infected meat

• infected food or water

• aerosolized blood or feces

What is tularemia classified as?

A category A bioagent

What kinds of infections does tularemia cause?

• ulcer glandular disease

• tularemic pneumonia

• typhoidal tularemia

What precautions must be taken with Francisella tularensis?

BSL-3 precautions

How does Francisella tularensis grow on most media?

Poorly, needs increased CO2

What agars will Francisella tularensis grow on?

• BCYE -contains cysteine

• CHOC with cysteine

• Thayer Martin Agar

What is the colony morphology of F. tularensis?

transparent, dew-drop, mucoid

What is the gram stain of F. tularensis?

Tiny, gram negative rod or coccobacilli, faintly staining

What are the oxidase and catalase reactions of P. multicida?

Catalase and oxidase positive

What are the oxidase and urease reactions for F. tularensis?

Oxidase and urease negative

Which misc gnrs are nitrate negative?

• Francisella tularensis

• Bordetella pertussus

What is the catalase and beta-lactamase reaction of F. tularensis?

Weak to both

Is F. tularensis biochemically active?

No, fairly inert

What are the major species of brucella?

• B. abortus (cattle)

• B. suis (swine)

• B. melitensis (goats and sheep, camels)

• B. canis (dogs)

Where is Brucella normal flora?

In the genital and urinary tracts of animals

How are humans infected with Brucella?

• infected meat and dairy

• close contact with animals

• breathing in organism

• skin wounds

What is Brucella classified as?

A category B bioagent

What is the causative agent of undulant fever?

Brucella

What are the symptoms of brucella infections?

• Acute infection: flu like symptoms, hepatosplenomegaly and weight loss

• Undulant fever

• can infect lymph nodes, spleen, liver and bone

How long must brucella cultures be held for and why?

21 days as brucella is a strict aerobe and grows slowly

What is in brucella agar?

TSA base, liver infusion, calf serum and yeast

What is the colony morphology of brucella?

Smooth, gray to translucent, non-hemolytic colonies

Which misc GNR will not grow on MAC?

• pasteurella multocida

• francisella tularensis

• Bordetella pertussis and parapertussis

How does Brucella spp use glucose?

Oxidatively

What are the catalase, oxidase, nitrate and urea reactions for brucella?

All positvie

Which brucella species produce H2S?

• brucella melitensis and abortus

• B. suis is variable

Which brucella spp will grow on basic fuchsin?

Brucella melitensis and abortus

Which brucella spp will growth with thionin?

Brucella melitensis and suis

How is bordetella spp spread?

Via airborne droplets

Which bordetella is the causative agent of whooping cough?

B. pertussis

Which bordetella spp causes a milder form of whooping cough?

Bordetella parapertussis

Which bordetella spp mainly infects the immunocompromised and those the work with animals?

Bordetella bronchiseptica

What infection does bordetella brochispetica cause in animals?

Kennel cough

What agars are brodetella grown on?

• bordet-gengou

• BCYE with 10% horse blood and 40mg/dl of cephalexin

What is the gram stain of bordetella?

Gram negative coccobacillus

How are bordetella specimens collected?

Nasopharyngeal swabs or washes

How long are bordetella species incubated for?

Seven days

Which bordetella are motility and nitrate negative?

Bordetella pertussis and parapertussis

Which Bordetella is oxidase negative?

B. parapertussis

Which bordetella are urease producers?

B. parapertussis (24 hr) and B. bronchiseptica (4 hr)

Which Bordetella spp will grow on MAC?

B. bronchiseptica

Which bordetella will grow on BA but not MAC?

B. parapertussis

Where is Legionella pneumonphila usually found?

Aquatic ecosystems, hot springs and lakes

How do human get legionella infections?

• airborne spread through AC and cooloing towers

• potable water

What are the two classical manifestations of legionella pneumophila

• Legionnarie’s diease

• pontiac fever

What are the ideal specimens for legionella infections?

sputum, blood and urine

What media will legionella grown on and do colonies appear?

BCYE and as round convex colonies with opalescent appearance

What is the gram stain for legionella?

Faint staining, thin gram negative rod

Is biochemical testing useful for the detection of legionella?

No, EIA and latex agglutination are more useful. FA stain and DNA probe also used to ID

What is bartonella henselae cause?

Cat scratch fever

How are humans infected with bartonella?

Cat scratches, flea feces containing bacterium

What are the symptoms of cat scratch fever?

• non-painful bump or blister at site of injury

• Painful swollen lymph nodes

• exhaustion, headache or fever

What is the gram stain of bartonella henselae?

Slightly curved gram negative rod

How is bartonella usually diagnosed?

Serologically with acute and convalescent sera two weeks apart, look for four fold dillution

What is Bartonella henselase’s oxidase reaciton?

Negative

What does the cultivation of leptospira interrogan require?

Fletcher or stuart’s media that contain rabbit or bovine serum albumin