A comparison of antibiotic disks from different sources on Quicolor and Mueller-Hinton agar media in evaluation of antibacterial susceptibility testing.
OBJECTIVE
Antibacterial susceptibility testing of clinical bacterial isolates through disk diffusion method plays a major role in antibacterial treatment. One of the main factors affecting the result of these tests is the type, structure and quality of the disks. The main objective of this study was to compare the agreement of antibiotic disks originated from three companies on Quicolor and Mueller-Hinton agar.


METHODS
Quicolor and Mueller-Hinton agar media were used in disk diffusion method. Seventy clinical isolates fromEnterobacteriaceaefamily (21Klebsiella spp.,36Escherichia coli,1Enterobacter spp. and 12Shigella spp.) were investigated in the study. After obtaining data, the results were interpreted as resistant, sensitive or intermediate. Kappa coefficient measured the agreement of two media. Coefficient of variation (CV) was also calculated for antibiotic disks.


RESULTS
The kappa agreement values for three types of antibiotic disks on Quicolor and Mueller-Hinton agar plates were good or excellent for all the examined antibiotics. CV values were also very satisfactory in the majority of cases.


CONCLUSIONS
Antibiotic disks from three manufacturers can successfully be used on both Quicolor and Mueller-Hinton agar plates.
Department of Biotechnology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran.
Neda
N
Saffari
Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran.
Siavosh
S
Salmanzadeh-Ahrabi
Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Tehran, Iran.
Ahya
A
Abdi-Ali
Institute of Health & Wellbeing, Health Economics & Health Technology Assessment, University of Glasgow.
Mohsen
M
Rezaei-Hemami
Antibiotic Disks; Disk Diffusion; Quicolor medium