PYR TEST KIT AND PYR REAGENT
|Cat. no. Z75||PYR Test Kit||25 tests/kit|
|Cat. no. Z175||PYR Test Kit||100 tests/kit|
|Cat. no. Z275||PYR Test Kit||75 tests/kit|
|* Cat. no. Z127||PYR Reagent||15ml|
|* This product sold separately|
Hardy Diagnostics PYR Test Kit and PYR Reagent are recommended for the detection of pyrolidonyl arylamidase (also called pyrolidonyl aminopeptidase) activity in certain groups of bacteria, such as Streptococcus pyogenes (group A strep), Enterococcus spp., some coagulase-negative staphylococci, and some Enterobacteriaceae.
PYR is a rapid colorimetric method for presumptive identification of certain groups of bacteria based on the activity of the enzyme pyrolidonyl arylamidase. L-pyroglutamic acid beta-naphthylamide is impregnated into the test disk or card and serves as the substrate for the detection of pyrolidonyl arylamidase. Hydrolysis of the substrate yields beta-naphthylamide which combines with the PYR Reagent (p-dimethylamino-cinnamaldehyde) to form a bright pink to cherry red color. A positive PYR tests allows for the presumptive identification of group A streptococci ( Streptococcus pyogenes ) and group D enterococci. In addition, investigators have determined that PYR activity is a key test for differentiation of some species of coagulase-negative Staphylococcus and for some genera of the family Enterobacteriaceae .
The PYR Test Kit contains disks (Cat. nos. Z75 and Z175) or filter paper (Cat. no. Z275) impregnated with L-pyroglutamic acid beta-naphthylamide and a reagent bottle of chromogenic solution (PYR Reagent); 0.015% p-dimethylaminocinnamaldehyde.
STORAGE AND SHELF LIFE
Upon receipt store at 2-8ºC. Do not remove PYR test cards (Cat. no. Z275C) from the sealed bag until ready to use. Products should not be used if there are any signs of deterioration or if the expiration date has passed. Protect reagents from freezing.
Specimen Collection: This product is not intended for primary isolation of patient specimens. It should be used only with cultures of isolated organism. This product is used in conjunction with other biochemical tests to identify cultures of isolated organism.
Method of Use: The Chromogenic Solution (PYR Reagent) is designed for use in the PYR Test Kit or with the StrepQuick™ (Cat. no. Z122). Moisten the PYR Disk or filter paper slightly with distilled or deionized water. Do not saturate. Alternatively, the disk may be placed on a blood agar plate, which will adequately moisten the disk. Using a sterile loop, pick 2-3 well isolated, 18-24 hour colonies (grown on a non-selective media such as Blood Agar, Cat. no. A10) and rub into a small area of the PYR Disk or filter paper so that there is a visible paste. After the test organism has been inoculated onto the disk or filter paper, allow it to react for two minutes. After this incubation period add one drop of Chromogenic Solution (PYR Reagent).
Note: Refer to the Instructions for Use (IFU) for StrepQuick™ for procedural use and interpretation of results.
INTERPRETATION OF RESULTS
A bright pink or cherry red color will appear within one minute if the test is positive. A negative test is indicated by no color change. The development of an orange, salmon, or yellow color should be interpreted as a negative reaction.
Organisms expected to give a positive result:
- Group A streptococci (Streptococcus pyogenes)
- Group D enterococci (Enterococcusspp.)
- Coagulase-negative Staphylococcus spp.: haemolyticus, lugdunensis and schleiferi
- Citrobacter, Klebsiella, Yersinia, Enterobacter and Serratia spp.
Removing PYR test cards (Cat. no. Z275C) from the sealed bag during long-term storage may result in a decreased shelf life. Maintain cards in the sealed bag until ready to use for best performance.
PYR may be used in the presumptive separation of group A streptococci and group D enterococci from other streptococci. Additional testing, using a pure culture, is recommended for complete identification.
It is important that testing first be performed to determine that the organism is in the Streptococcus genus. Only group A streptococci and group D enterococci are PYR-positive. Other streptococci are negative; however additional testing, using a pure culture, may be necessary to separate group A streptococci (S. pyogenes) from beta-hemolytic enterococci.
A Gram stain and catalase test should be performed to confirm the presence of gram-positive, catalase-negative cocci. The ability to hydrolyze bile esculin may be used to presumptively identify group D enterococci.
Some Staphylococcus, Aerococcus, Lactococcus, most Corynebacterium (Arcanobacterium) haemolyticum, as well as some Enterobacteriaceae and other gram-negative bacilli, are also PYR-positive.
Rare gram-positive cocci will be positive in this test but are not enterococci or group A streptococci. These organisms appear in a Gram stained smear arranged in tetrads or clusters. Additionally, the organisms produce tiny colonies and are not significant pathogens.
A false-negative test can result if the disk or filter paper are too moist.
Weak, pale results occur with the disk test for Staphylococcus aureus; positive results may need to be confirmed with other tests or with the tube PYR test, which is available in commercial rapid identification kits.
False-negative tests can result if selective media or tube biochemical agars are used to provide inocula.
Most human infections associated with group D streptococci are caused by Enterococcus faecalis and Streptococcus bovis.
Escherichia coli and indole-positive Proteus spp. obtained from media containing a high tryptophan content may yield a blue-green color development. This is a negative result.
MATERIALS REQUIRED BUT NOT PROVIDED
Standard microbiological supplies and equipment such as loops, forceps, StrepQuick™ (Cat. no. Z122), Blood Agar (Cat. no. A10), incinerators, and incubators, etc., as well as serological and biochemical reagents, are not provided.
ATCC ® 29212
|Positive; pink to cherry red color change|
|Positive; pink to cherry red color change|
|Negative; no color change|
|Negative; blue color change|
User Quality Control
It is recommended that each new lot or shipment be tested with known positive and negative controls. (1,5)
PYR Test Disks and filter paper should appear white in
color. Disks and filter paper should not be used if they appear pink or
red in color.
- Chromogenic Solution (PYR Reagent) should appear clear and colorless with no precipitate.
Showing positive PYR reaction with the PYR Test Kit
(Cat. no. Z75).
Enterococcus faecalis(ATCC® 29212) growth was applied to a PYR Disk moistened with deionized water and incubated at room temperature for two minutes. Subsequently, one drop of Chromogenic Solution (PYR Reagent) was applied to the disk. The pink to red color development was indicative of a positive PYR reaction.
Showing negative PYR reaction with the PYR Test Kit
(Cat. no. Z75).
Streptococcus agalactiae (ATCC® 12386) growth was applied to a PYR Disk moistened with deionized water and incubated at room temperature for two minutes. Subsequently, one drop of Chromogenic Solution (PYR Reagent) was applied to the disk. No pink to red color development was indicative of a negative PYR reaction.
PYR Test Kit (Cat. no. Z75).
1. Anderson, N.L., et al. Cumitech 3B; Quality Systems in the Clinical Microbiology Laboratory, Coordinating ed., A.S. Weissfeld. American Society for Microbiology, Washington, D.C.
2. Versalovic, J., et al. Manual of Clinical Microbiology. American Society for Microbiology, Washington, D.C.
3. Tille, P., et al. Bailey and Scott's Diagnostic Microbiology, C.V. Mosby Company, St. Louis, MO.
4. Ellner, P.D., et al. 1985. Preliminary evaluation of a rapid colorimetric method for the presumptive identification of group A streptococci and enterococci. J. Clin. Microbiol.; 22:880-881.
Isenberg, H.D. Clinical Microbiology Procedures Handbook, Vol. I, II & III. American Society for Microbiology, Washington, D.C.
ATCC is a registered trademark of the American Type Culture Collection.