Abstract
A total of 34 isolates ofListeria monocytogenes were tested against ampicillin, cephalothin, chloramphenicol, erythromycin, tetracycline, and penicillin-G using the Autobac 3-h AIS and the Autobac 5-h MIC procedures. The results were compared to susceptibility category interpretations and MICs determined using the Sceptor system. With the Sceptor System, all isolates were interpreted to be moderately susceptible to ampicillin and penicillin-G, and susceptible to the four other antibiotics. With the Autobac AIS, all isolates were interpreted to be susceptible to all the antibiotics except penicillin-G. All but one of the 34 isolates were interpreted to be resistant to penicillin-G with the Autobac AIS test. The remaining isolate was interpreted to be indeterminant. The Autobac AIS test was unsatisfactory for determining the susceptibility ofL. monocytogenes isolates to penicillin-G. The Autobac MIC results correlated well with the MIC results of the Sceptor system provided that the Autobac was programmed as though it were testing enterococci. The Autobac MIC reported penicillin-G MICs in units per milliliter and required the use of a conversion factor to obtain micrograms per milliliter, and did not allow for the testing of erythromycin. The Autobac MIC susceptibility category interpretations must not be used, as they were derived from an outdated susceptibility standard. The Autobac MIC test may be used if the limitations given above are observed.
Similar content being viewed by others
Literature Cited
Fleming DW, Cochi, SL, MacDonald KL, Brondum J, Hayes PS, Plikaytis BD, Holmes MB, Audurier A, Brome CV, Reingold AL (1985) Pasteurized milk as a vehicle of infection in an outbreak of listeriosis. N Engl J Med 312:404–407
Morbidity and Morality Weekly Report (1985) Listeriosis outbreak associated with Mexican-style cheese: California. Morbid Mortal Week Rep 34:357–359
National Committee for Clinical Laboratory Standards (1980) Standard methods for dilution antimicrobial susceptibility tests for bacteria which grow aerobically. Proposed standard: PSM-7. Villanova PA: National Committee for Clinical Laboratory Standards
National Committee for Clinical Laboratory Standards (1984) Performance standards for antimicrobial disk susceptibility tests: M2-A3. Villanova PA: National Committee for Clinical Laboratory Standards
National Committee for Clinical Laboratory Standards (1985) Methods for dilution antimicrobial susceptibility tests for bacteria that grow aerobically: M7-A. Villanova PA: National Committee for Clinical Laboratory Standards
Schlech III WF, Lavigne PM, Bortolussi RA, Allen AC, Haldane EV, Wort AJ, Hightower AW, Johnson SE, King SH, Nicholls ES, Broome CV (1983) Epidemic listeriosis: evidence for transmission by food. N Engl J Med 308:203–206
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Dillon, P.A., Overman, S.B. & Overman, T.L. Rapid determination of antimicrobial susceptibility patterns ofListeria monocytogenes isolates by the autobac AIS and MIC procedures. Current Microbiology 15, 137–140 (1987). https://doi.org/10.1007/BF01577261
Issue Date:
DOI: https://doi.org/10.1007/BF01577261