A tube coagulase test was performed on catalase-positive, gram-positive cocci that were ?-hemolytic and grew on mannitol salt agar. The tube was checked after overnight incubation and was negative. Which of the following statements explains this discrepancy?
a. A tube coagulase should not be performed on a catalase-positive organism.
b. A ?-hemolytic colony, which is catalase positive and grows on mannitol salt, is normally coagulase negative.
c. The test should have been read in 1 to 4 hours in case any hemolysins are present.
d. No discrepancy is present; the results are accurate.
C
Some strains of S. aureus produce fibrinolysin, which will dissolve the clot after 4 hours of in-cubation at 35°C and may appear to be negative if allowed to incubate longer than 4 hours.
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Which ocean zone extends from low tide to the edge of the continental shelf?
a. Neritic zone b. Intertidal zone c. Abyssal zone d. Aphotic zone
Water has a high heat capacity because it has ____
a. covalent bonds b. ionic bonds c. low freezing point d. high boiling point e. hydrogen bonds
Protists in this group have a pellicle, and a light-sensitive organ called the stigma.
A. euglenoids B. dinoflagellates C. choanoflagellates D. foraminifera
For many plants to grow well in hot, dry weather they must be watered so their stomata will remain open for longer periods of time to let in carbon dioxid E.
a. true b. false