Antimicrobial drugs bacterial resistance

The phenomenon of bacterial resistance to antibiotics was already known by the pioneers of the era of antibiotics, like Paul Ehrlich, who coined the term selective toxicity as the basic principle of antimicrobial therapeutics, as well as Gerhard Domagk, the inventor of the sulfonamide drugs, and Sir Alexander Fleming, the discoverer of the penicillins. When penicillin G was introduced into clinical practice in 1944, as many as 5% of the isolates of Staphylococcus aureus were resistant to penicillin, while 5 years later the percentage was 50%. 

Bacterial resistance to conventional antibiotics has become a serious problem in infection control, and has led to intensive research efforts to develop an effective novel antimicrobial agent. Antimicrobial peptides have already played a crucial role in pharmaceutical research as biomedically useful agents or as lead compounds for drug development. More specifically, cyclic peptides have shown some potential as a possible new class of... 

The use of a combination of a glucocorticoid with an antimicrobial drug is illogical and should generally be avoided because of the possibility of the emergence of resistant bacterial strains. It would be highly preferable if prescriptions for these drugs were issued by... 

To prevent the rapid development of bacterial resistance. Erythromycin and rifampin are used in combination in the treatment of foals with Rhodococcus (R.) equi infections. Each drug has a completely different mechanism of antimicrobial action their combination reduces the chance of chromosomal mutations conferring bacterial resistance. 

Drugs used prophylactically should not be those that are used routinely for therapy, to avoid bacterial resistance caused by previous exposure to that antimicrobial agent. 

Apart from a very occasional anaphylactic reaction, antimicrobial agents do not produce clinically observable pharmacological effects unless (acute reaction) or until toxicity is manifested. The latter is generally associated with multiple dosing that leads to drug accumulation and can be precipitated by the presence of a concurrent disease state, such as renal function impairment or hepatic dysfunction. Inherent dangers associated with the indiscriminate use of antimicrobials are the widespread development of bacterial resistance and the production of toxicity without premonitory signs. 

For most of the drug substances the environmental impact is unknown, but for different types of antibiotics or antimicrobials a lot of concern is raised because of the development of bacterial resistance towards the drugs through different molecular mechanisms (Kruse and Sorum, 1994). This poses a threat to animals as well as humans, with the development of multiresistant, sometimes pathogenic, microbial strains (Midtvedt, 1998)... 

Many of the new antimicrobials are clearly outstanding contributions to the art of chemotherapy and are, as such, real triumphs of pharmacological research. Others are molecular modifications of established compounds and are introduced with claims that some desired feature—such as greater potency, more rapid absorption, more sustained blood levels, reduced bacterial resistance, or fewer side effects—has been added to the more familiar properties. Since all such claims need to be viewed skeptically until they have been confirmed by impartial investigators and extended experience, compounds of this type often make only a numerical rather than a qualitative contribution to the list of available drugs, and thus add only confusion. 

There are food safety issues present today that deserve attention. These include bacterial resistance to antimicrobial drugs that result in food contamination by resistant bacteria and human consumption of beef from cows that... 

TESTING FOR MICROBIAL SENSITIVITY TO ANTIMICROBIAL AGENTS Bacterial strains, even from the same species, may vary widely in sensitivity to antibiotics. Information about the antibiotic sensitivity of the infecting microorganism is important for appropriate drug selection. Various methods are used to assess susceptibility, including disk-diffusion, dilution test, and automated broth dilution. The results are either reported on a semi-quantitative scale i.e., resistant, intermediate, or susceptible) or in terms of the minimal inhibitory concentration (MIC). 

Up to the present, the perfect antibiotic has not been found. [67] The problem is, that our armamentarium of drugs is facing a multitude of diverse pathogens, which have perfected their survival strategies under permanent selection pressure over millions of years. Microorganisms are able to adapt to changing conditions of their environment by rapid mutations. For each new antibiotic, it is only a matter of time, before resistance ruins its antimicrobial efficacy. There is a continuous race between the innovation cycle for new drugs and the reoccurrence of bacterial resistance. While the time it takes to develop a new pharmaceutical compound cannot be shortened at will, every effort should be made to ensure an extended therapeutic benefit of currently available antibiotics. 

Reviews - The experimental aspects of the chemotherapy of tuberculosis were reviewed by Batten, clinical aspects were discussed editorially. Browne reviewed the treatment of leprosy. A favorable editorial comment was made on the use of an antimutagen (quinacrlne) with standard treatment of urinary tract Infection to prevent the rise of resistant bacterial strains. Lampe examined the changing concepts in the therapy of urinary tract disease. The not unrelated fields of sulfonamides, and nitro-furans were also reviewed. The resistance development as a consequence of antimicrobial drugs in animal feeds was examined. Topical antimicrobials were reviewed in several contexts antiseptics and disinfectants, soap bacteriostats,deodorants and antlperspirants,and antimicrobial biguanides. The topical treatment of burns and the renaissance of mafenide for such use was discussed by Moncrief. Veterinary ophthalmic antimicrobials were reviewed. 

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