certain groups of bacteria, such as Streptococcus pyogenes (A group... some coagulase-negative staphylococci, and some Enterobacteriaceae.


PYR Test Kit and PYR Reagent

are used for the detection of pyrolidonyl arylamidase activity in certain groups of bacteria, such as Streptococcus pyogenes (A group strep), Enterococcus spp., some coagulase-negative staphylococci, and some Enterobacteriaceae.


PYR is a rapid method for presumptive identification of bacteria based on the pyrolidonyl arylamidase enzyme. L-pyroglutamic acid beta-naphthylamide impregnated into the strip which serves as the substrate for the pyrolidonyl arylamidase. Catabolism of the substrate produces betanaphthylamide which reacts with the PYR Reagent to form a pink/fuchsia color. A positive

PYR Test enables presumptive identification of grup A streptococci and grup D enterococci. In addition, investigators have reached a consensus that PYR activity is a key test for differentiation of some species of coagulase-negative Staphylococcus and for some genera of the family



PYR Test Kit contains test strips saturated with L-pyroglutamic acid beta-naphthylamide and chromogenic PYR reagent solution with p-dimethylaminocinnamaldehyde.


1. Take 2 or 3 colonies, cultured in non-selective medium like blood-agar, with the help of inoculation loop and spread them into the reaction site of strip.

2. Drip 10 µl of distilled or deionized water on the strip with a pipette. Avoid excessive use of water.

3. Organism to be tested should be inoculated into the test strip. In order to react, wait approximately 2 minutes.

4. After this incubation period a drop of chromogenic solution (PYR Reagent) should be added.

Chromogenic solution designated to use with the PYR Test Kit.


A pink/fuchsia color formation occurs within 30 to 60 seconds in positive test. Negative test is implying none of color change.


Testing of each new lot or shipment with the known positive or negative control microorganisms is suggested.

Reaction section of test strip should appear white. Pink/ fuchsia coloring strips should not be used.

Chromogenic Solution (PYR Reagent) should appear clear and yellow color with no precipitate. Organisms routinely in used quality control tests at LABORATORIOS CONDA are given below:

Tested Microorganism

Enterococcus faecalis

(ATCC® 29212)

Streptococcus agalactiae

(ATCC® 12386)

Escherichia coli

(ATCC® 25922)

Enterobacter aerogenes

(ATCC® 13048)


Positive; pink/fuchsia color appears.

Negative; no color change observed.

Negative; no color change observed.

Positive; pink/fuchsia color appears



Removing PYR Test strips from original package during storage might cause shortening on expiration date. In order to obtain better results keep strips in the container when they are not use.

PYR might be used in the presumptive identification of group A streptococci and group

D enterococci from other streotococci. For complete identification additional testing is required with the pure-culture.

A false-negative result can be obtained when the strips are too moist or culture to be tested is not pure.

Staphylococcus aureus

could be give weak, slight positive results with the strip test. To

be confirmed positive reactions further tests.

Escherichia coli

and indole-positive

Proteus spp

. cultures obtained from a rich tryptophan containing media may lead blue-green color formation. This result concluded as a negative reaction.

PYR Test strips must be used only for in vitro diagnostic use. Test is designed for professional use and should be used in a laboratory by trained personnel using aseptic and safety methods.

Cause irritation in eye, skin or respiratory system. Product includes carcinogenic content. Sterilize all hazard waste before disposition.


PYR Test Kit should be store at +2 between +8 ºC.

Protect from direct sunlight.

Do not remove PYR strips from its container until ready to use.

Products should not be used if there are any impairment or if the expiration date has passed.

Do not use products if they do not give positive or negative result when they are tested with the known control organisms.

Expiration date is valid for the products stored at given conditions and unopened original packages.


R. R. Facklam, J. F. Padula, L. G. Thacker, E. C. Wortham, And B. J. Sconyers (1974), Presumptive Identification of

Group A, B, and D Streptococci, Applied Microbiology, 27, 107-113.

A.R. Bennett, S. Macphee, R. Betts, D. Post (1999), Use of Pyrrolidonyl Peptidase to Distinguish Citrobacter from

Salmonella, Letters in Applied Microbiology, 28, 175-178.

S. Bascomb, M. Manafi (1998), Use of Enzyme Tests in Characterization and Identification of Aerobic and

Facultatively Anaerobic Gram-Positive Cocci, Clinical Microbiology Reviews,11, 318-340.