Effectiveness of Disc Diffusion Method for Vancomycin Sensitivity Testing of Staphylococcus aureus [Letter]

Dear editor

We read this study¹ with great interest. This study focused on isolation, identification and antibiotic sensitivity pattern of bacterial isolates from postsurgical site infections in public hospitals in Northern Jordan. The study mentioned various methods to identify bacterial isolates, which were further subjected to antibiotic sensitivity testing as per CLSI guidelines.²

We would like to add some comments regarding this study and suggest the criteria for identification and antibiotic sensitivity testing need to be urgently revisited:

1. A minor change needs to be made in the title, which indicates it as a multicentric study involving several hospitals in Northern Jordan, whereas author has collected samples from one single hospital.
2. The susceptibility testing using vancomycin against Staphylococcus aureus is not recommended by any disk diffusion method as per CLSI guidelines.² Authors in the present study have used vancomycin 30 µg disc against Staphylococcus aureus.
3. Authors have reported that 87.5% of Staphylococcus aureus were sensitive to vancomycin, which is not acceptable due to the use of incorrect methodology. In this context, Vancomycin Resistant Staphylococcus aureus (VRSA) being a high priority pathogen as per WHO report-2017 should be identified by the currently acceptable method(s).³

Nevertheless, we congratulate the authors who focused on characterizing pathogenic isolates from various postsurgical site infection in a public health hospital in Northern Jordan.