Abstract
An original algorithm referred to as the radial profile analysis algorithm was implemented on a Macintosh Quadra 700 computer to provide an automatic determination of the inhibition zone diameters of antibiotic susceptibility tests performed with the disk diffusion method. After digitization of the petri plate image, each antibiotic disk is recognized and labeled. Pixels of the local zone around each disk are then used for generating a profile pattern that is subjected to decision rules. The resulting estimate of the inhibition zone diameter is then automatically compared with conventional breakpoints for classifying the tested strain in one of the clinical categories of antibiotic susceptibility. The program is also able to request a human reading for some rare plates difficult to interpret. The algorithm accuracy was tested by comparing the results with a combination of independent human measurements performed on the tested plates. The test sample was composed of 98 strains, and 2,552 tests of 40 distinct antibiotics were subjected to the analysis. The difference between the automatic and human diameter estimates was less than 4 mm in 90% of the tests. The agreement between the automatic and human clinical categorizations amounted to 95.5%, and severe (major and very major) disagreements were found in 5.6% of the tests performed with staphylococci but only 0.3% of the tests with gram-negative rods. We conclude that the radial profile analysis algorithm is a solid backbone for an automatic system dedicated to the clinical interpretation of disk diffusion antibiotic susceptibility tests.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Backes B. A., Cavalieri S. J., Rudrik J. T., Britt E. M. Rapid antimicrobial susceptibility testing of Gram-negative clinical isolates with the AutoMicrobic system. J Clin Microbiol. 1984 Jun;19(6):744–747. doi: 10.1128/jcm.19.6.744-747.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bauer A. W., Kirby W. M., Sherris J. C., Turck M. Antibiotic susceptibility testing by a standardized single disk method. Am J Clin Pathol. 1966 Apr;45(4):493–496. [PubMed] [Google Scholar]
- D'Amato R. F., Hochstein L., Vernaleo J. R., Cleri D. J., Wallman A. A., Gradus M. S., Thornsberry C. Evaluation of the BIOGRAM antimicrobial susceptibility test system. J Clin Microbiol. 1985 Nov;22(5):793–798. doi: 10.1128/jcm.22.5.793-798.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kelly M. T., Latimer J. M., Balfour L. C. Comparison of three automated systems for antimicrobial susceptibility testing of gram-negative bacilli. J Clin Microbiol. 1982 May;15(5):902–905. doi: 10.1128/jcm.15.5.902-905.1982. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nolte F. S., Krisher K. K., Beltran L. A., Christianson N. P., Sheridan G. E. Rapid and overnight microdilution antibiotic susceptibility testing with the Sensititre Breakpoint Autoreader system. J Clin Microbiol. 1988 Jun;26(6):1079–1084. doi: 10.1128/jcm.26.6.1079-1084.1988. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Philippon A., Labia R., Jacoby G. Extended-spectrum beta-lactamases. Antimicrob Agents Chemother. 1989 Aug;33(8):1131–1136. doi: 10.1128/aac.33.8.1131. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Reiber N. E., Kelly M. T., Latimer J. M., Tison D. L., Hysmith R. M. Comparison of the Cathra Repliscan II, the AutoMicrobic system Gram-Negative General Susceptibility-Plus Card, and the Micro-Media System Fox Panel for dilution susceptibility testing of gram-negative bacilli. J Clin Microbiol. 1985 Jun;21(6):959–962. doi: 10.1128/jcm.21.6.959-962.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sanders C. C., Sanders W. E., Jr Emergence of resistance to cefamandole: possible role of cefoxitin-inducible beta-lactamases. Antimicrob Agents Chemother. 1979 Jun;15(6):792–797. doi: 10.1128/aac.15.6.792. [DOI] [PMC free article] [PubMed] [Google Scholar]