Studies on the Mechanism of Antibiotic-Resistance Acquirement by Enterobacteriaceae

I Report: Antibiotic-resistance of E. coli in the intestinal tract

Abstract

Antibiotic-resistance of E. coli was measured with 132 patients in the National-Ashikaga Sanatorium and 1, 138 healthy persons of various collective bodies in order to clarify the mechanism of antibiotic-resistance acquirement by enterobacteriaceae.
Antibiotic-resistance of E. coli was determined using Mac Conkey medium containing 25 ry/ml of chloramphenicol (CM), streptomycin (SM) and tetracycline (TC). Tuberculosis patients demonstrated in 83.33% and general healthy persons in 32.69%
over 25 ry/ml resistance against each one of CM, SM and TC. Over 100 ry/ml resistance against each one of the 3 antibiotics was found in 50.76% of tuberculosis patients and in 17.57% of general healthy persons.
In tuberculosis patients SM-single-resistant strains were most frequently encountered (16.67%), followed by two-antibiotics (SM, TC)-resistant strains (13.64%), threeantibiotics-resistant ones (10.67%), TC-single-resistant one (7.58%) and two-antibiotics (CM, SM)-resistant ones (3.03%), respectively. In general healthy persons, resistant strains against various antibiotics were isolated in the following percentage order:
TC-single ones in 6.94%, SM-single ones in 6.5%, CM. SM. TC-resistant ones in 2.02%, SM. TC-resistant ones in 1.32%, CM. TC-resistant ones in 0.35% and CM. SM resistant ones in 0.09%.
In tuberculosis patients treated with SM, the isolation rate of SM-highly-resistant strains was 56.00%, that of three-antibiotics-resistant ones 12.00%, that of CM. SMresistant ones 2.00%, that of SM. TC-resistant ones 20.00%, SM-single resistant ones 12.00% and TC-single-resistant ones 10.00%, revealing that a high resistance not only against SM but also against TC and CM was acquired by the bacilli.
An increasing tendency of the isolation rate of E. coli with a high antibiotic-resistance was recognized in general healthy persons in the year of 1960.