Evaluation of Pastorex Staph Plus Rapid Agglutination Test to Confirm Staphylococcus aureus Isolated from Clinical Specimens in a Tertiary Care Teaching Hospital

Abstract

Background: Staphylococcus aureus is one of the most common pathogen isolated. Accurate and rapid identification of S. aureus and MRSA is of great importance for proper care of the patient. Keeping this in mind, we had used Pastorex Staph plus rapid agglutination test to confirm S. aureus. Aim: To evaluate Pastorex Staph plus rapid agglutination test for confirming Staphylococcus aureus isolated from clinical specimens. Study Design: Cross-sectional type. Methodology: This study was conducted in a tertiary care hospital in Eastern India. It included all clinical samples, where Staphylococcus spp. was isolated. The phenotypic confirmation of the isolate was done by slide coagulase test, tube coagulase test, mannitol fermentation test and Pastorex Staph plus rapid agglutination test. Methicillin Resistant Staphylococcus aureus (MRSA) strains were identified as per CLSI 2017 guideline. Statistical analyses of the results were done to evaluate the validity, diagnostic accuracy & reliability of the tests. Tube coagulase test was taken as the gold standard test. Results: Among the total 83 Staphylococcus spp. isolates, 31 isolates (37%) were Staphylococcus aureus. Among these S. aureus isolates, only 1(3.2%) isolate was MRSA. Statistical analysis showed that, in identification of Staphylococcus aureus, Pastorex Staph plus test had highest sensitivity (100%), specificity (98%) and diagnostic accuracy (98.4%) with Cohen’s Kappa coefficient as 0.97. Conclusion: Considering the sensitivity, specificity, accuracy and Cohen's kappa coefficient, it was concluded that Pastorex Staph plus rapid agglutination test can be used as rapid and effective method to diagnose S. aureus.