Chloramphenicol and tetracycline

Studies by Levine et al. (1983) have addressed the issue of plasmid mobilizations, the movement of plasmids between different host cells. Human volunteers fed tetracycline along with E. coli HS-4 (typical of the normal intestinal flora of humans) bearing highly mobilized plasmids (e.g., pJBK5) that carried resistance to chloramphenicol and tetracycline became co-colonized with E. coli HS-4 bearing the antibiotic-resistant plasmid. However, the use of a poorly mobilizable plasmid (pBR325) did not result in plasmid transfer. 

Example 2 Chloramphenicol and Tetracycline—Sparingly soluble broad-spectrum antibiotics like chloramphenicol and tetracycline found to damage the gastrointestinal epithelium besides changing the normal micro-flora in the Gl-tract that are required for normal good health. 

Inhibition of protein synthesis in microorganisms (aminoglycosides, erythromycin, clindamycin, chloramphenicol, and tetracyclines). 

Table 13.27 Results of Sulfonamides, Chloramphenicol, and Tetracyclines Residues Surveys from 1992 to 1995 in Switzerland...

With the differential pulse polarography [245], the antibiotics can be determined at low concentration, if necessary, at the ppm or even sub-ppm level. Tetracycline hydrochloride is determined in aqueous acetate buffer pH 4 (detection limit 0.1 ppm), but for the analysis of chlortetracycline hydrochloride, oxytetracycline hydrochloride and free tetracycline, a non-aqueous medium must be used. Streptomycin sulphate is analysed in alkaline solution, trace quantities of zinc being masked by Na2EDTA, and the detection limit is 1 ppm. A determination in blood serum or urine is also possible but the peak potentials are shifted here to more negative values. The polarographic determination is preceded by ultrafiltration. Penicillin G potassium and ampicillin must be first functionalised by nitrosation. The authors also recommend an analysis of mixtures which is however demonstrated only with chloramphenicol and tetracycline, at 2.4 and 4.2 ppm, respectively. 

Two drugs, chloramphenicol and tetracycline, interact with rRNA through atoms that are coordinated by both the drugs and the RNA phosphate oxygens (11, 14). Shared metal coordination is not a common interaction between drug and proteins it remains to be seen if this is a common phenomenon for RNA/antibiotic complexes or not. 

Umezawa and coworkers first described streptomycin adenylyl transferase in E. coli K12 ML1629 carrying an R factor resistant to streptomycin, kanamycins A, B, and C, paromamine, neamine, paromomycin, neomycin, chloramphenicol, and tetracycline, and confirmed that the inactivated product is adenylylstreptomycin. 

Antibiotics have been used for the treatment of infectious diseases and for a number of non-human applications (agriculture, animal husbandry, and aquaculture) during the past 70 years (Levy and Marshall 2004). Prior to the introduction of antibiotics, natural populations of human/animal bacterial pathogens or commensal bacteria were susceptible to antibiotics (Hughes and Datta 1983). Immediately after the entry of antibiotics in the treatment of infectious diseases, the appearance of antibiotic-resistant bacteria was observed. Today, the overwhelming majority of enterobacteria are resistant to sulfonamides, the first antibacterial chemotherapeutics introduced in clinical practice in 1937. Additionally, a high proportion of bacteria are resistant to a broad range of penicillins, streptomycin, chloramphenicol, and tetracyclines. 

Praus, R., Brettscheider, L., Kreja, L. and Kalvadora, D., 1972. Hydrophilic contact lenses as a new therapeutic approach for topical use of chloramphenicol and tetracycline. Ophthalmologica 165 62. 

In some strains of yeast, mutation to chloramphenicol and tetracycline resistance are associated with a decreased permealnlity of the cell-memln ane, while in the same strains mutation to macrolide (oythromydn) resistance is expressed as a change in the sensitivity of the mitochondrial protein-synthesizing system itself. For the same cell, erythromycin resistance was also shown to be extrachromosomi-cally inherited, and the corresponding genetic factor related to the mitochondrial Rho factor. The synthesis of yeast mitochondrial ribosomes seons to be (at least partly) under the control of the mitochondrial goietic determinant MDNA. 

The ability of streptomycin, under certain conditions, to induce misreading of the genetic code and to produce nonsense polypeptides, may be phenomena of the laboratory unrelated to the clinical use of this drug (Luzzatto, Apirion, and Schlessinger, 1968). Streptomycin is lethal to cells only when they are vigorously engaged in protein synthesis. For this reason, some other inhibitors of protein synthesis, notably chloramphenicol and tetracycline, interfere with the antibacterial action of streptomycin. 

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