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Chin Med J (Taipei) 1997;59:259-64.
Section of Bacteriology, Division of Clinical Pathology, Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan, R.O.C.
Background. Group A streptococci and enterococci can be differentiated from other streptococci on the basis of their ability to cleave L-pyrrolidonyl-beta-naphthylamide.
Methods. In the present study, the L-pyrrolidonyl-beta-naphthylamide (PYR) test, pigment medium and bile esculin medium have been used to presumptively identify the streptococci. In total, 114 strains of group A streptococci, 350 strains of non-group A streptococci, 202 strains of enterococci and 197 strains of non-enterococci have been tested.
Results. The results of the present investigation show that sensitivities of different test methods are: PYR broth, 99.08%; Murex PYR, 98.48%; bacitracin, 95%; bacitracin and sulfamethoxazole/trimethoprim (SXT), 95%; pigment medium, 99.23%; bile esculin medium, 99.26%. Additionally, specificities of various tests are: PYR broth and Murex PYR, 99.82%; bacitracin, 90.90%; bacitracin and SXT, 98.87%; pigment medium and bile esculin medium, 100%, respectively.
Conclusions. PYR test has been observed to be very easy to use and may hence be considered as a rapid, reliable and cost-effective method for presumptive identification of group A streptococci and enterococci in the clinical laboratory.
[Chin Med J (Taipei) 1997;59:259-64.]
Keywords: enterococci, group A streptococci, PYR test
Received: April 20, 1996.
Accepted: February 4, 1997.
Address reprint requests to:
Chi-Hsiang Chen
Section of Bacteriology
Division of Clinical Pathology
Department of Pathology
Tri-Service General Hospital
National Defense Medical Center
No. 8, Section 3, Ting Chow Road
Taipei, Taiwan, R.O.C.
Copyright: 1997, Chinese Medical Association (Taipei)