Rothia
Cards (10)
- Rothia
- belong to the family microococcaceae
- nitrate positive
- non motile
- esculin hydrolysis positive
- urease negative
- approximately 2/3 of the isolate are catalase (+)
- contains 6 spp. but only 2 are significant
- Rothia mucilaginosa
- linked to bacteremia, endocarditis, pneumonia
- Rothia dentocariosa
- member of the normal human oropharyngeal flora and found in saliva
- Listeria monocytogenes
- Listeriosis is recognized as an uncommon but serious infection primarily of neonates, pregnant women, older adultS, and IMCP
- Virulence Factors of Rothia
- Hemolysin (listeriolysin O) which damages the phagosome membrane and effectively preventing killing of the organism by macrophages
- Catalase
- Superoxide dismutase
- Phospholipase C
- Surface protein (p60) which induces/influencing phagocytosis
- Clinical Infections
- Pregnant women - listeria can be seen on the third trimester of pregnancy - listeria monocytogenes can be responsible for spontaneous abortion and stillborn neonates
- Newborns - similar to S. agalactiae infections
- Early onset listeriosis : can cause illness shortly after birth and is associated with sepsis or infection within the amniotic fluid
- Late onset listeriosis : disease occur several days to two weeks and is most likely to manifest at meningitis
- Laboratory Diagnosis
- Gram-positive coccobacillus
- Found in singly, in short chains, or in palisades
- Grows well on SBA, chocolate agar, nutrient agar, brain-heart infusion medium and thioglycolate broth
- Prefers a slightly increased carbon dioxide (CO2)
- Colonies: small, round, smooth, and translucent surrounded by narrow zone of B-hemolysis which may be visualized only if the colony is removed
- Optimal growth temperature: 30 to 35 C but growth occurs over a wide range : 0.5 - 45 C
- Listeria monocytogenes grows at 4 C, a technique called cold enrichment may be used to isolate the organism from polymicrobial clinical specimens
- can survive at refrigerator temperature under conditions of low pH and high salt concentration
- Culture media of choice: McBride Medium
- Identification of Rothia spp.
- Hippurate hydrolysis (+) like S. agalactiae
- Positive in catalase and bile esculin hydrolysis
- Motile at room temp
- Wet mount preparations: tumbling motility
- In motility medium: umbrella (if incubated at room temp 22-25 C but not on 35 C)
- Produces a positive CAMP reaction