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Relationship of Antibiotic Resistance to Effectiveness in Rhizobium trifolii Populations
Author(s) -
Hagedorn C.
Publication year - 1979
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1979.03615995004300050021x
Subject(s) - antibiotics , chloramphenicol , tetracycline , streptomycin , biology , antibiotic resistance , rhizobium , microbiology and biotechnology , bacteria , genetics
Fifty Rhizobium trifolii isolates were divided into five categories of symbiotic effectiveness and examined for resistance to 15 antibiotics. The cultures were resistant to high concentrations of 11 of the antibiotics but were relatively sensitive to chloramphenicol, streptomycin, tetracycline, and vancomycin. Resistance to any particular group of antibiotics was not associated with any one of the different categories of effectiveness but rather was equally dispersed between all categories. Eighteen isolates which differed in effectiveness were used to develop subcultures resistant to 3× or 4× the average minimum inhibitory concentration (MIC) of the parent strains for each of the antibiotics. Reduction in effectiveness was found in 12.5% of the resistance strains, was not associated with any particular antibiotic, and was randomly distributed throughout the five effectiveness categories. Increased effectiveness occurred with only three subcultures (2.5% of the tests). Cross‐resistance patterns were generally restricted to those antibiotics which expressed similar modes of activity and the development of cross‐resistance occurred in 5.7% of the possible resistance combinations. Results presented in this study do not agree with other reports in which antibiotics were divided into groups based on their association with effectiveness.