Comparison of rapid and conventional methods for investigating of mecA presence in Staphylococcus Species

Objectives: Taking the determination of mecA gene by polymerized chain reaction (PCR) method as a reference in determining methicillin resistance in Staphylococcus species, we aimed at comparing the reliability levels of disk diffusion, latex agglutination test and chromogenic agar use methods.

Methods: This prospective study was conducted on 228 Staphylococcus strains isolated between January 2020 and December 2020 in Samsun Training and Research Hospital. Disk diffusion, latex agglutination and chromogen agar medium methods were applied along with the polymerized chain reaction (PCR) method.

Results: The mecA gene was detected in 47 of the isolates (20.6%) by the PCR method, and these isolates were accepted as methicillin-resistant. When the PCR result was taken as a reference, the sensitivity of the disk diffusion method became 100%, and specificity became 45.9%; sensitivity of latex agglutination was determined as 80.9%, and specificity as 70.2%; sensitivity of chromogenic agar as 85.1% and its specificity was found to be 95%. Only in S. aureus isolates, the highest sensitivity and specificity rate (100% and 88%, respectively) belonged to chromogenic agar.

Conclusion: Chromogenic agar provides more reliable data for S. aureus isolates, and the combined use of all three methods does not significantly increase reliability.