Studies on Streptomycin Resistance in Pathogenic Bacteria Isolated from Diseased Lettuce

Abstract

Pseudomonas cichorii, Ps. marginalis pv. marginalis, Ps. viridiflava, Xanthomonas campestris pv. vitians and Erwinia carotovora subsp. carotovora were isolated from diseased lettuce of various localities in Japan, and their resistance to streptomycin was investigated in vitro. Two point seven percent of Ps. cichorii isolates and 3.6% of Ps. viridiflava isolates were highly resistant to streptomycin (minimal inhibitory concentrations at 200 and 400ppm, respectively), and 9.1% of the latter was moderately resistant (at MIC 25 to 100ppm). The MIC for 7.7% of the isolates of E. carotovora subsp. carotovora was within the range of 50 to 100ppm. None of the isolates of Ps. marginalis pv. marginalis and X. campestris pv. vitians was resistant to streptomycin.