Coagulase test: Difference between revisions

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**Checks for agglutination after a drop of plasma is combined with a suspension of the bacteria on a slide
 
**Checks for agglutination after a drop of plasma is combined with a suspension of the bacteria on a slide
 
**Positive if clumping is apparent within 10 seconds or less, and no clumping is observed in saline or water
 
**Positive if clumping is apparent within 10 seconds or less, and no clumping is observed in saline or water
**A few species of [[coagulase-negative staphylococci]] may be positive due to membrane-bound clumping factor, including [[Staphylococcus lugdenensis]] and [[Staphylococcus intermedius]]
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**A few species of [[coagulase-negative staphylococci]] may be positive due to membrane-bound clumping factor
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***[[Staphylococcus lugdenensis]], [[Staphylococcus schleiferi]] subsp. ''schleiferi'', [[Staphylococcus sciuri]] subsp. ''carnaticus'', [[Staphylococcus sciuri]] subsp. ''rodentium'', and [[Staphylococcus intermedius]]
 
**[[Staphylococcus aureus]] is negative in 15% of tests, especially MRSA, so negative results need to be confirmed with tube coagulase
 
**[[Staphylococcus aureus]] is negative in 15% of tests, especially MRSA, so negative results need to be confirmed with tube coagulase
 
*'''Tube coagulase'''
 
*'''Tube coagulase'''
 
**Mix a heavy inoculum of bacteria into a tube filled with rabbit plasma
 
**Mix a heavy inoculum of bacteria into a tube filled with rabbit plasma
 
**Positive if clot is formed within 4 hours when incubated at 37ºC
 
**Positive if clot is formed within 4 hours when incubated at 37ºC
**A few species of [[Coagulase-negative staphylococci]] may be positive
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**A few species of [[Coagulase-negative staphylococci]] may be positive: [[Staphylococcus intermedius]], [[Staphylococcus saccharolyticus]], and [[Staphylococcus schleiferi]]
   
 
[[Category:Diagnostics]]
 
[[Category:Diagnostics]]

Revision as of 18:31, 23 August 2020