Increased Resistance to Several Antibiotics by One Mutation in an R-factor, R 1a

R-factor-mediated resistance to tetracycline in Proteus mirabilis.

The expression of R-factor-mediated resistance to tetracycline has been compared in Proteus mirabilis and Escherichia coli. Resistance to a range of concentrations of tetracycline was significantly lower in P. mirabilis than in E. coli in both induced and repressed states. Indirect evidence showed that conditions which result in a marked increase in the level of resistance of P. mirabilis harbo...

Mechanism of R factor-mediated chloramphenicol resistance.

Gentamicin resistance in Pseudomonas aeruginosa: R-factor-mediated resistance.

By disk diffusion antimicrobial susceptibility testing, 11% of 313 consecutive strains of Pseudomonas aeruginosa, examined during July to October 1973, were resistant to gentamicin (minimal inhibitory concentration 12.5 to >100 mug/ml), and a further 31% were moderately resistant (6.25 to 12.5 mug/ml) to gentamicin at the University of Alberta Hospital in Edmonton, Canada. Of 45 gentamicin-resi...

Introduction to Several Concepts of Convexity and Semicontinuity for Function from R to R

We adopt the following convention: a, b, r, s, x0, x are real numbers, f , g are partial functions from R to R, and X, Y are sets. The following propositions are true: (1) max(a, b) ­ min(a, b). (2) Let n be a natural number, R1, R2 be elements of R , and r1, r2 be real numbers. Then R1 a 〈r1〉 • R2 a 〈r2〉 = (R1 • R2) a 〈r1 · r2〉. (3) Let n be a natural number and R be an element of R. Suppose ∑...

Conjugal fertility associated with resistance factor R in Escherichia coli.

Sugino, Yoshinobu (Osaka University, Osaka, Japan) and Yukinori Hirota. Conjugal fertility associated with resistance factor R in Escherichia coli. J. Bacteriol. 84:902-910. 1962.-The introduction of the contagious drug-resistance factor, R, into an F(-) strain of Escherichia coli allows the R(+)F(-) strain to mate with F(-)R(-) strains. The chromosome fragment transferred from the R(+) cell is...