HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Silver, H. K. Articles by Kempe, C. H. Search for Related Content PubMed Articles by Silver, H. K. Articles by Kempe, C. H.

Resistance to Streptomycin

A Study of the Mechanisms in Its Development^*

From the Department of Pediatrics, University of California Medical School and the Children's Hospital, San Francisco

Abstract

A test of sensitivity to streptomycin employing the fertile egg as the culture-medium has been used to study the mechanism of the development of resistance to streptomycin.

The sensitivity to streptomycin of the individual components making up a single strain of E. coli was found to vary widely. When the results of the tests were plotted, they formed a typical standard curve of distribution.

Similar variations of sensitivities were found when the individual components of a resistant strain of E. coli were tested.

The results of our experiments support the belief that a single strain of a micro-organism may show remarkable variation in the response of its individual components to an antibiotic.

It is suggested that tests of susceptibility to streptomycin should be done on a mixed suspension of many colonies of any strain of an organism rather than upon one or a few isolated colonies in order to avoid the inadvertent testing of either extreme in the range of sensitivities of the individual components.

In our experiments, single strains of E. coli and A. aërogenes could be made extremely resistant to streptomycin by being cultured on the chorioallantoic membrane of fertile eggs to which had been added constant sub-inhibitory amounts of streptomycin.

Changes in the morphological structure of E. coli and of A. aërogenes were noted after exposure of the organisms to streptomycin, but these changes were unrelated to sensitivity.

Footnotes

^* Presented before the seventeenth annual meeting of the Society for Pediatric Research at Stockbridge, Mass. on May 13, 1947.

Aided by grants form the Rosenberg Foundation and the Fleischner Endowment Fund for the Study, Prevention and Treatment of Communicable Diseases in Childhood.

The authors wish to acknowledge the technical assistance of Mrs. Tillie B. Leake.