Infectious Diseases Plate Rounds 1-24-24

1. Plate Round Discussion 1/24/24
• Case 1: Strep constellatus endocarditis
• Case 2: Clostridium ramosum in blood cultures
• Case 3: Bergeyella zoohelcum from cat bite
• Case 4: Haemophilus parainfluenzae bacteremia and endocarditis

2. Streptococcus
Constellatus
• Regarded generally as harmless
commensals of the oropharyngeal,
urogenital and gastrointestinal
microbiota
• These organisms are strongly
associates with abscess formation in
the brain, the oropharynx, or the
peritoneal cavity
• Streptococcus constellatus is a viridans
Streptococcus belonging to the
anginosus group.

3. Diagnostic testing
• Odor butterscotch or caramel
• Colonies can be alpha or beta hemolytic,
white, translucent, convex, matte
• Gram positive cocci in chains
• Catalase neg, optochin-R, Bile esculin neg,
PYR-neg
• Facultative anaerobic

4. Clostridium
ramosum
• Ubiquitous in nature, being found in
the soil and feces from animals and
human.
• Isolated from infants and adult feces,
indigenous to the human intestinal
tract
• Can cause bacteremia
• Produces spores hence why it is placed
in the clostridium genus

5. Diagnostic testing
• Gram positive Bacilli
• Occurring singly, in pairs or in short chains,
often in “V” arrangements, with a “rail
fence” or in irregular masses
• Nonhemolytic
• Obligate anaerobic
• Indole neg, catalase neg, H2S neg,
characteristically resistant to rifampin

6. Bergeyella
zoohelcum
• Found in environment, does not
belong to the normal flora of the
humans
• Resides in the upper respiratory
tract of dogs and cats
• Mainly found in wounds caused by
animal's bites
• Meningitis or septicemia can occur
from bite or continuous contact
with animal

7. Diagnostic testing
• Gram Negative Rod
• Obligate aerobic
• Colonies are sticky and tan to
yellow
• No growth on MAC
• Catalase pos, Oxidase pos, Indole
pos, urease pos,

8. Haemophilus
parainfluenzae
• Opportunistic pathogen that has been
associated with endocarditis,
bronchitis, otitis, conjunctivitis,
pneumonia, abscesses and genital
tract infections.
• H. parainfluenzae and H. aphrophilus
cause endocarditis.
• Can be found as part of the normal
flora of the mouth and pharynx

9. Diagnostic Testing
• Gram Negative tiny Bacilli or
coccobacillary
• X factor neg, V factor positive with no
hemolysis
• No growth on MAC
• Oxidase pos,H2S pos