Bacteriostatic drug

Sulphanilamide, the simplest member of a large series of bacteriostatic drugs, can readily be prepared by the following reactions. Acetanilide, when treated v ith an excess of chlorosulphonic acid, gives p-acetaniidobenzencsulphonyl chloride (Reaction A), w hich readily reacts with ammonia to give p-acetamido-benzenesulphonamide (Reaction H). The acetamido-group in the latter... 

Antimicrobial drugs can be classified as bacteriostatic (for example, tetracyclines, sulfonamides) and as bactericidal (for example, penicillin). Bacteriostatic drugs inhibit bacterial growth, but do not destroy these organisms in clinically attainable concentrations. It should be expected that the MBC of such drugs will be significantly higher than the MIC. 

Thus sulfonamides are bacteriostatic drugs that inhibit bacterial growth by interfering with the microbial synthesis of folic acid. More specifically, sulfonamides block the biosynthetic pathway of folic acid synthesis, thus competitively inhibiting the transformation of p-aminobenzoic acid to folic acid (mediated by the enzyme dihydropteroate synthetase), which allows them to be considered as antimetabolites. 

Both sulfonamides and trimethoprim (not a sulfonamide) sequentially interfere with folic acid synthesis by bacteria. Folic acid functions as a coenzyme in the transfer of one-carbon units required for the synthesis of thymidine, purines, and some amino acids and consists of three components a pteridine moiety, PABA, and glutamate (Fig. 44.1). The sulfonamides, as structural analogues, competitively block PABA incorporation sulfonamides inhibit the enzyme dihydropteroate synthase, which is necessary for PABA to be incorporated into dihydropteroic acid, an intermediate compound in the formation of folinic acid. Since the sulfonamides reversibly block the synthesis of folic acid, they are bacteriostatic drugs. Humans cannot synthesize folic acid and must acquire it in the diet thus, the sulfonamides selectively inhibit microbial growth. 

Bacteriostatic drug. It is effective against a variety of gram positive and negative organisms including E. coli and Aerobacter. It is most commonly used as urinary antiseptic for prophylaxis and treatment of urinary tract infections. 

Antimicrobial sulpha drugs, e.g. sulphanilamide, are the amide of sulpha-nilic acid, and certain related substituted amides. Sulphanilamide, the first of the sulpha drugs, acts by inhibiting the bacterial enzyme that incorporates para-aminobenzoic acid into folic acid. Sulphanilamide is a bacteriostatic drug, i.e. inhibits the further growth of the bacteria. 

Effects of bactericidal and bacteriostatic drugs on the growth of bacteria in vitro. 

This type of kinetic analysis of growth inhibition works with predominantly bacteriostatic drugs such as chloramphenicol or the tetracyclines25 but has been extended to the study of the bactericidal antibiotic, streptomycin26. ... 

Less used in modern clinical practice, the classification is somewhat arbitrary because most bacteriostatic drugs can be shown to be bactericidal at high concentrations, under certain incubation conditions in vitro and against some bacteria. 

Bacteriostatic drugs inhibit the growth and multiplication of bacteria, but do not directly kill them (e.g. sulfonamides, tetracyclines, chloramphenicol). 

Bacteriostatic drugs, actively taken up by susceptible bacteria... 

In contrast to many other, primarily bacteriostatic drugs, both colistin and polymyxin rarely induce resistance during repeated passage of normally sensitive strains in subinhibitory concentrations. 

A bacteriostatic drug inhibits the further growth of bacteria a bactericidal drug kills the bacteria. In recent years, many bacteria have become resistant to all antibiotics, so drug resistance has become an increasingly important problem in medicinal chemistry. 

A bacteriostatic drug interferes with bacterial cell function and impairs the ability of the bacteria to reproduce. Thus, the bacterial population is gradually reduced, as the organisms gradually die out and are not replaced. 

Does a bacteriostatic drug kill the cell directly ... 

List possible mechanisms of action for a bacteriostatic drug. 

Antibacterial drugs can be either bactericidal or bacteriostatic The effectiveness of bacteriostatic drugs depends on an intact host immune system. Antimicrobial agents may be administered singly or in combination. Some combinations induce synergy and/or delay emergence of resistance. 

Figure 7.3 Bacteriostatic drugs require an intact immune system to eradicate an infection.

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