Observations on the in Vivo and in Vitro Development of Bacterial Resistance to Streptomycin

Abstract

The problem of acquired resistance of microorganisms is of importance in the clinical use of the sulfona nides, but present knowledge indicates it is of lesser importance with penicillin therapy. Early work (Waksman et al., 1945) with streptomycin indicated that it might prove even more unfavorable than the sulfonamides in this respect, and recent work has confirmed these early indications. Persistence of infection after streptomycin therapy has been reported by Herrell and Nichols (1945) and Reimann et at. (1945). Buggs and coworkers (1946) noted the appearance of resistant strains after streptomycin therapy, and Miller and Bohnhoff (1946) have produced rapidly increasing resistance in vitro by culturing organisms on agar containing streptomycin. The latter authors showed that repeated subcultivation on agar containing streptomycin induced resistance of both gonococci and meningococci so rapidly that only 4 to 6 daily transfers to a medium containing streptomycin were necessary to permit abundant growth in the presence of 75,00 micrograms of streptomycin per ml. In vivo experiments confirmed the invitro resistance, since the streptomycin-resistant strains of meningococci could notbe controlled bythe largest doses of streptomycin tolerated by animals. Finland et al. (1946) has recently reported that gramnegative organisms causing urinary tract infections develop a high degree of resistance to streptomycin during treatment. In a series of 12 cases of infection with various gram-negative organisms treated with streptomycin, 8 failed to show any beneficial effects. Five of these organisms on isolation were found to have acquired more than a 4,000-fold resistance to the drug following a 48-hour treatment schedule.In an experiment designed to increase the in vitro resistance of a variety of organisms to streptomycin and streptothricin, it was found that some developed resistance rapidly, while others were not materially changed in their sensitivity to these drugs. Fourteen organisms from a stock culture collection were subjected to various amounts of the two antibiotics in broth. The organisms studied included gram-negative and gram-positive rods and cocci. The following method was utilized for increasing the resistance of the organisms under test:Each organism was subcultured from a nutrient agar slant to standard methods broth, pH 7.8, and incubated overnight. With stock solutions of streptomycin and streptothricin, which were prepared by diluting weighed aliquots of these drugs in sterile 1 per cent phosphate buffer (pH 6.0), twofold serial dilutions of each antibiotic were prepared daily. The dilution series usually consisted of ten 100 X 13 mm test tubes, each containing 0.5 ml of the antibiotic dilution.To each tube was added 1.5 ml of a 1:100 dilution in broth of the 18-to 24-hour 481 on July 16, 2020 by guest

Bacteriological Studies of Aureomycin

“…Such substances as peptone, beef extract, and even phosphate buffer at pH 6. 3 materially reduce the activity of the drug in a relatively short period of time. It is apparent that the use of a thioglycollate medium tends to preserve the potency of aureomycin to a greater degree than the other media utilized.…”

Antibacterial activity of garlic extract on streptomycin-resistant Staphylococcus aureus and Escherichia coli solely and in synergism with streptomycin

“…To increase the resistance of the strain to the particular antibiotic, the procedure described above was repeated. [ 5 ]…”

Observations on Bacteria Sensitive to, Resistant to, and Dependent upon Streptomycin

“…Some differences, such as alteration in motility and changes in growth rate and in biochemical reactions, have been reported, but these have been inconsistent (Graessle and Frost, 1946;Klein and Kimmelman, 1946;Murray et al, 1946;Petroff and Lucas, 1946;Seligmann and Wassermann, 1947;Stubblefield, 1947). Streptomycin-resistant organisms have ordinarily been obtained in vitro by repeated subculture in increasing concentrations of this antibiotic (Chandler and Schoenbach, 1947;Miller and Bohnhoff, 1946;Murray et al, 1946;Price et al, 1947;Seligmann and Wassermann, 1947), though the occurrence of a few very resistant organisms in a large inoculum of sensitive ones on initial exposure to streptomycin has been described in the case of Shigella (Klein, 1947), Escherichia coli (Clark and Rantz, 1947;Klein, 1947), Staphylococcus aureus (Klein, 1947), Staphylococcus albus (Klein, 1947), Proteus vulgaris (Klein, 1947), Hemophilus influenzae (Alexander and Leidy, 1947), meningococcus (Miller and Bohnhoff, 1947a), and Mycobacterium tuberculosis (Vennesland, Ebert, and Bloch, 1947).…”