Journal article
Agar Disk Diffusion and Automated Microbroth Dilution Produce Similar Antimicrobial Susceptibility Testing Results for Salmonella Serotypes Newport, Typhimurium, and 4,5,12:i-, But Differ in Economic Cost
Foodborne pathogens and disease, Vol.8(12), pp.1281-1288
12/01/2011
Handle:
https://hdl.handle.net/2376/115610
PMCID: PMC3263306
PMID: 21877930
Abstract
Data generated using different antimicrobial testing methods often have to be combined, but the equivalence of such results is difficult to assess. Here we compared two commonly used antimicrobial susceptibility testing methods, automated microbroth dilution and agar disk diffusion, for 8 common drugs, using 222
Salmonella
isolates of serotypes Newport, Typhimurium, and 4,5,12:i-, which had been isolated from clinical salmonellosis cases among cattle and humans. Isolate classification corresponded well between tests, with 95% overall category agreement. Test results were significantly negatively correlated, and Spearman's correlation coefficients ranged from −0.98 to −0.38. Using Cox's proportional hazards model we determined that for most drugs, a 1 mm increase in zone diameter resulted in an estimated 20%–40% increase in the hazard of growth inhibition. However, additional parameters such as isolation year or serotype often impacted the hazard of growth inhibition as well. Comparison of economical feasibility showed that agar disk diffusion is clearly more cost-effective if the average sample throughput is small but that both methods are comparable at high sample throughput. In conclusion, for the
Salmonella
serotypes and antimicrobial drugs analyzed here, antimicrobial susceptibility data generated based on either test are qualitatively very comparable, and the current published break points for both methods are in excellent agreement. Economic feasibility clearly depends on the specific laboratory settings, and disk diffusion might be an attractive alternative for certain applications such as surveillance studies.
Metrics
7 Record Views
Details
- Title
- Agar Disk Diffusion and Automated Microbroth Dilution Produce Similar Antimicrobial Susceptibility Testing Results for Salmonella Serotypes Newport, Typhimurium, and 4,5,12:i-, But Differ in Economic Cost
- Creators
- Karin Hoelzer - 1Department of Food Science, Cornell University, Ithaca, New YorkKevin J Cummings - 2Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New YorkLorin D Warnick - 2Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New YorkYnte H Schukken - 2Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New YorkJulie D Siler - 2Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New YorkYrjo T Gröhn - 2Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New YorkMargaret A Davis - 3Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WashingtonTom E Besser - 3Department of Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, Pullman, WashingtonMartin Wiedmann - 1Department of Food Science, Cornell University, Ithaca, New York
- Publication Details
- Foodborne pathogens and disease, Vol.8(12), pp.1281-1288
- Academic Unit
- Veterinary Microbiology and Pathology, Department of; Paul G. Allen School for Global Animal Health
- Publisher
- Mary Ann Liebert, Inc
- Identifiers
- 99900547581401842
- Language
- English
- Resource Type
- Journal article