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an enzyme that induces coagulation

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2012/11/01 13:17:36」(JST)

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(TEM cryomicroscopy technique) - S. aureus forms a fibrin capsule that protects it from the immune system of cattle

Coagulase is a protein enzyme produced by several microorganisms that enables the conversion of fibrinogen to fibrin. In the laboratory, it is used to distinguish between different types of Staphylococcus isolates. Importantly, S. aureus is coagulase-positive, meaning that coagulase negativity excludes S. aureus.

It is also produced by Yersinia pestis.^[1]

Coagulase reacts with prothrombin in the blood. The resulting complex is called staphylothrombin, which enables the enzyme protease to convert fibrinogen to fibrin. This results in clotting of the blood. Coagulase is tightly bound to the surface of the bacterium S. aureus and can coat its surface with fibrin upon contact with blood. It has been proposed that fibrin-coated staphylococci resist phagocytosis, making the bacteria more virulent. Bound coagulase is part of the larger family of MSCRAMM.

Coagulase test

The coagulase test is used to differentiate Staphylococcus aureus from coagulase-negative staphylococci. S.aureus produces two forms of coagulase (i.e., bound coagulase and free coagulase). Bound coagulase, otherwise known as "clumping factor", can be detected by carrying out a slide coagulase test, and free coagulase can be detected using a tube coagulase test.

Slide test

A slide coagulase test is run with a negative control to rule out autoagglutination. Two drops of saline are put onto the slide labeled with sample number, Test (T) and control (C). The two saline drops are emulsified with the test organism using a wire loop, straight wire, or wooden stick. A drop of plasma (rabbit plasma anticoagulated with EDTA is recommended)^[2] is placed on the inoculated saline drop corresponding to test, and mixed well, then the slide is rocked gently for about 10 seconds.

If 'positive', macroscopic clumping would be observed in the plasma within 10 seconds, with no clumping in the saline drop.
If 'negative', no clumping will be observed.

If the slide coagulase test is negative, a tube test should follow as a confirmation. Clumping in both drops is an indication of autoagglutination, so a tube test should be carried out.

Tube test

A fibrin clot formed in a test tube by the coagulase reaction

The tube test uses rabbit plasma that has been inoculated with a staphylococcal colony (i.e., Gram-positive cocci which are catalase positive). The tube is then incubated at 37°C for 1.5 hours. If negative, then incubation is continued up to 18 hours.

If 'positive' (i.e., the suspect colony is S. aureus), the serum will coagulate,^[3] resulting in a clot (sometimes the clot is so pronounced, the liquid will completely solidify).
If 'negative', the plasma remains a liquid. The negative result may be S. epidermidis but only a more detailed identification test can confirm this, using biochemical tests as in analytical profile index tests methods. A false negative can be perceived if the sample is not allowed to cool for about 30 minutes at room temperature or 10 minutes in the freezer, given that the serum can melt. If truly negative, the serum will remain liquid after cooling.

List of coagulase-positive staphylococci: Staphylococcus aureus subsp. anaerobius, S. a. aureus, S. a. delphini, S. hyicus, S. intermedius, S. lutrae, and Staphylococcus schleiferi subsp. coagulans.

List of coagulase-negative staphylococci of clinical significance: S. saprophyticus, S.cohnii subsp. cohnii, S. cohnii subsp. urealyticum, S. captitus subsp. captitus, S. warneri, S.hominis, S.epidermidis, S. caprae, and S.lugdunensis

References

^ "coagulase" at Dorland's Medical Dictionary
^ A.Forbes, Betty; Daniel F.Sahm, Alice S.Weissfeld. BAILEY& SCOTT'S Diagnostic Microbiology (Tenth Edition ed.). Don Ladig. pp. 430–431. ISBN 0-8151-2535-6.
^ "coagulase test" at Dorland's Medical Dictionary

External links

Tube coagulase test - rabbit plasma video
Coagulase at the US National Library of Medicine Medical Subject Headings (MeSH)
Coagulase test procedure

UpToDate Contents

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1. コアグラーゼ陰性ブドウ球菌による感染症の治療 treatment of infections due to coagulase negative staphylococci
2. コアグラーゼ陰性ブドウ球菌の疫学、微生物学、および病因 epidemiology microbiology and pathogenesis of coagulase negative staphylococci
3. メチシリン耐性黄色ブドウ球菌の微生物学 microbiology of methicillin resistant staphylococcus aureus
4. コアグラーゼ陰性ブドウ球菌による感染症の臨床症状 clinical manifestations of infection due to coagulase negative staphylococci
5. 血管内カテーテル感染症治療 treatment of intravascular catheter related infections

English Journal

Assessment of the suitability of mannitol salt agar for growing bovine-associated coagulase-negative staphylococci and its use under field conditions.

De Visscher A, Haesebrouck F, Piepers S, Vanderhaeghen W, Supré K, Leroy F, Van Coillie E, De Vliegher S.SourceM-team and Mastitis and Milk Quality Research Unit, Department of Reproduction, Obstetrics, and Herd Health, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium. Electronic address: Anneleen.Devisscher@UGent.be.
Research in veterinary science.Res Vet Sci.2013 Oct;95(2):347-51. doi: 10.1016/j.rvsc.2013.05.015. Epub 2013 Jul 1.
This study aimed at testing the applicability of mannitol salt agar (MSA), a medium generally used in human medicine for differentiating Staphylococcus aureus from coagulase-negative staphylococci (CNS), for culturing bovine-associated CNS species. All test isolates from a comprehensive collection o
PMID 23809647

Real-time evaluation of milk quality as reflected by clotting parameters of individual cow's milk during the milking session, between day-to-day and during lactation.

Leitner G, Merin U, Jacoby S, Bezman D, Lemberskiy-Kuzin L, Katz G.Source1 National Mastitis Reference Center, Kimron Veterinary Institute, PO Box 12, Bet Dagan 50250, Israel.
Animal : an international journal of animal bioscience.Animal.2013 Sep;7(9):1551-8. doi: 10.1017/S1751731113000542. Epub 2013 Mar 28.
Real-time analysis of milk coagulation properties as performed by the AfiLab™ milk spectrometer introduces new opportunities for the dairy industry. The study evaluated the performance of the AfiLab™ in a milking parlor of a commercial farm to provide real-time analysis of milk-clotting paramete
PMID 23537499

Antimicrobial Activity of the Pleuromutilin Antibiotic BC-3781 against Bacterial Pathogens Isolated in the SENTRY Antimicrobial Surveillance Program in 2010.

Paukner S, Sader HS, Ivezic-Schoenfeld Z, Jones RN.SourceNabriva Therapeutics AG, Vienna, Austria.
Antimicrobial agents and chemotherapy.Antimicrob Agents Chemother.2013 Sep;57(9):4489-95. doi: 10.1128/AAC.00358-13. Epub 2013 Jul 8.
BC-3781 is a novel semisynthetic pleuromutilin antibiotic inhibiting bacterial protein synthesis. BC-3781 has completed a phase 2 clinical trial in acute bacterial skin and skin structure infections (ABSSSI). Its antibacterial spectrum additionally covers the predominant pathogens causing community-
PMID 23836172

Japanese Journal

Clinical significance of methicillin-resistant coagulase-negative staphylococci obtained from sterile specimens

Tashiro Masato,Izumikawa Koichi,Ashizawa Nobuyuki,Narukawa Munetoshi,Yamamoto Yoshihiro
Diagnostic Microbiology and Infectious Disease 81(1), 71-75, 2015-01
… Distinguishing true coagulase-negative staphylococci bacteremia from contamination remains a challenge. … We conducted a retrospective analysis of 183 patients with methicillin-resistant coagulase-negative staphylococci (MR-CoNS)-positive and methicillin-resistant Staphylococcus aureus-positive cultures obtained from sterile sites such as blood, synovial fluid, ascitic fluid, and cerebrospinal fluid. …
NAID 120005526596

コアグラーゼ試験およびラテックス凝集反応 : Staphylococcus属の鑑別におけるピットフォール

三澤慶樹,吉田敦,奥住捷子
日本臨床微生物学雑誌 = The journal of the Japanese Society for Clinical Microbiology 25(1), 19-25, 2015
NAID 40020317672

尿管皮膚瘻造設術後症例における尿培養分離菌の検討

村井亮介,窪田成寿,金哲將
泌尿器科紀要 = Acta urologica Japonica 60(12), 605-609, 2014-12
… One methicilline-resistant coagulase-negative Staphylococcus (MRCNS) strain was isolated. …
NAID 120005528124

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リンク元	「コアグラーゼ」「凝固酵素」
拡張検索	「bound coagulase」「coagulase-negative staphylococcal infection」「hemocoagulase」