Coagulase test: Difference between revisions
From IDWiki
mNo edit summary |
No edit summary |
||
| Line 4: | Line 4: | ||
**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 |
**A few species of [[coagulase-negative staphylococci]] may be positive due to membrane-bound clumping factor |
||
***[[Staphylococcus lugdenensis]], [[Staphylococcus schleiferi]] subsp. ''schleiferi'', [[Staphylococcus sciuri]] subsp. ''carnaticus'', and [[Staphylococcus sciuri]] subsp. ''rodentium'' |
***[[Staphylococcus lugdenensis]], [[Staphylococcus schleiferi]] subsp. ''schleiferi'', [[Staphylococcus sciuri]] subsp. ''carnaticus'', and [[Staphylococcus sciuri]] subsp. ''rodentium'' |
||
| ⚫ | |||
*'''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 |
||
Revision as of 19:11, 23 August 2020
- Used to differentiate Staphylococcus aureus from less pathogenic coagulase-negative staphylococci
- Tests for the ability of the organism to convert fibrinogen into fibrin (that is, to form a clot)
- Slide coagulase
- 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
- Staphylococcus aureus is negative in 15% of tests, especially MRSA, so negative results need to be confirmed with tube coagulase
- A few species of coagulase-negative staphylococci may be positive due to membrane-bound clumping factor
- Staphylococcus lugdenensis, Staphylococcus schleiferi subsp. schleiferi, Staphylococcus sciuri subsp. carnaticus, and Staphylococcus sciuri subsp. rodentium
- Tube coagulase
- 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
- A short list of animal-associated staphylococci are also coagulase-positive: Staphylococcus intermedius (dogs), Staphylococcus schleiferi subsp. coagulans, Staphylococcus hyicus, Staphylococcus lutrae, Staphylococcus delphini (dolphins), and Staphylococcus pseudintermedius (dogs)1
References
- ^ Takashi Sasaki, Sae Tsubakishita, Yoshikazu Tanaka, Arihito Sakusabe, Masayuki Ohtsuka, Shintaro Hirotaki, Tetsuji Kawakami, Tsuneo Fukata, Keiichi Hiramatsu. Multiplex-PCR Method for Species Identification of Coagulase-Positive Staphylococci. Journal of Clinical Microbiology. 2010;48(3):765-769. doi:10.1128/jcm.01232-09.
