Fastidious & Miscellaneous Gram Neg Bacilli

Question 1

Name 9 fastidious GNB groups (leave out species); FIVE have a similarity in naming that should help! One is an acronym for a whole group.

Answer 1

Haemophilus; Legionella, Bordetella, Francisella, Brucella, Pasteurella; Capnocytophaga; Streptobacillus moniliformis; The HACEK group;

Question 2

which Haemophilus organisms require X factor, what IS X factor, and what do they NOT possess as well which is why they require it?

Answer 2

H. influenzae, H. haemolyticus, H. aegyptius, and H. ducreyi They don’t convert ALA to porphyrins

Question 3

What is factor X, factor V, and which are found in CHOC and SBA?

Answer 3

Factor X is hemin (an iron-containing porphyrin) and is in both SBA and CHOC; Factor V is NAD, nicotinamide adenine dinucleotide; It is found only in CHOC bc blood cells must be lysed to release it; This is why most Haemophilus only grow on CHOC (ducreyi doesn’t need it but it is fastidious in other ways, like needs more CO2 and enriched CHOC)

Question 4

Name the 3 “Ellas” that cause zoonotic infections and the 2 non-ella we listed

Answer 4

Francisella, Pasteurella, Brucella, Capnocytphage, and Streptobacillus moniliformis

Question 5

what are the HACEK organisms other than haemophilus?

Answer 5

Aggregatibacter aphrophilus and A. actinomycetemcomitans, Cardiobacterium hominis, Eikenella, and Kingella

Question 6

What causes “rat bite fever” / Haverhill fever and describe its:

1. colonies and gram stain
2. culture requirements

Answer 6

Streptobacilllus moiliformis

1. puffball colonies; gram-neg pleomorphic can be filamentous or look like strings of beads
2. requires media with serum added, ie 20% horse serum and a CO2 incubator

Question 7

what can all the HACEK organisms cause in adults?

Answer 7

endocarditis

Question 8

Descrive Capnocytophaga :

1. source
2. oxidase/catalase/motility
3. morphology of rods
4. growth requirements

Answer 8

1. dog/cat bite
2. ox/cat positive; gliding motility on agar
3. fusiform
4. needs CO2 and often CHOC/supplemented agar

Question 9

What does Francisella need to grow? appearance on gram stain?

how should suspected Francisella be handled?

Answer 9

Cystine, so prefer g;ucose-cystine agar or cystine enriched BCYE; grows on enriched choc in 48 hrs…

coccobacilli gram negative.

As a bio safety level 3 organism, must use bio safety cabinet

Question 10

what is the cause of undulant fever? Source: give spp associated with which animal

Answer 10

Brucella spp.

B. abortus- cow

B. melitensis- sheep/goats

B. suis- pigs

Question 11

How can brucellosis be contracted? two ways

Answer 11

traditionally by handling livestock; now more often from unpasteurized dairy

Question 12

describe undulant fever and the other effects of infection possibel with Brucella

Answer 12

undulant fever means rising and falling in waves;

usually infections cause lymphadenopathy, hepatosplnomegaly, and smelly sweat; also can cause spontaneous abortion, hepatitis and endocarditis

Question 13

describe the effect of infection with Francisella adn give the colloquial name of the infection

Answer 13

rabbit or deer fly fever- usually caught from an arthropod bite or exposure to infected animals (rabbits etc)

causes ulceroglandular infection and regional lymph node enlargement

Question 14

specimen of choice for Brucella isolation>

Answer 14

blood or especially BONE MARROW

Question 15

Brucella colony requirements

Answer 15

routine media but over 7 to 10 days in 5-10% CO2

Question 16

Pasteurella is associated with what mode of transmission?

Answer 16

animal bites, especially cats

Question 17

describe the gram stain and biochemicals of Pasteurella multocida compared to Bartonella henselae: (note Bartonella not included in our main list but it is a fastidious gram negative curved bacilli

Answer 17

Pasteurella multocida: gram negative coccobacilli, nonmotile and may stain bipolar (safety pin, like Y. pestis which is in ENterobacteralis group); it is super positive: catalase, oxidase, indole, nitrate!! Grows well on nonselective agars except MAC

Bartonella henselae causes cat-scratch fever (lymphadenopathy) and also hepatitis and angiomatosis. Oxidase negative, curved gram negative bacilli

Question 18

which HACEK organism may pit the agar and has bleachy odor (colonies); known to be caused by human bites…or from punching someone in mouth

Answer 18

Eikenella corrodens

Question 19

WHat kinds of infection can the gram negative coccobacillary HACEK organims Kingella cause? more than just endocarditis. Describe the appearnce of the bacteria

Answer 19

it can also cause pediatric bone & joint infections; it is bacillary to coccobacillary and can join in chains much like the clostridium except it is gram negative and doesn’t make spores.