Bactericidal drug

Bactericidal drugs cause death of microbial cells and their lysis at clinically attainable concentrations. For such drugs, the MBC is close or equal to the MIC. Treatment with bacteriostatics stops bacterial growth, thus allowing neutrophils and other protective powers of the body to remove the pathogen. 

Bacitracin is a bactericidal drug that inhibits the formation of linear peptidoglycan chains, which are the main component of bacterial cell membranes. Most Gram-positive bacteria,... 

Bactericidal drug for both gram positive and negative bacteria. Acts by inhibiting enzymes necessary for carbohydrate metabolism in bacteria. It is available as ointment. Used for the topical treatment of superficial wounds and skin infections. FURACIN 0.2% ointment/cream. 

It is bactericidal drug and exerts its action by combining with bacterial ribosome and induces misreading of mRNA codons. Also in sensitive bacteria, disruption of cytoplasmic membrane occurs resulting in leakage of amino acids, ions, leading to bacterial death. 

It is bactericidal drug and it exerts it action by inhibiting the synthesis of the cell wall in sensitive bacteria. 

It is the most active drug used in the treatment of tuberculosis. It is a hydrazide of isonicotinic acid. It is a bactericidal drug, effective against Mycobacterium tuberculosis and ineffective against atypical mycobacteria. 

Chloramphenicol inhibits hepatic microsomal enzymes that metabolize several drugs. Half-lives are prolonged, and the serum concentrations of phenytoin, tolbutamide, chlorpropamide, and warfarin are increased. Like other bacteriostatic inhibitors of microbial protein synthesis, chloramphenicol can antagonize bactericidal drugs such as penicillins or aminoglycosides. 

Antibacterial agents may be classified as bacteriostatic or bactericidal (Table 51-3). For agents that are primarily bacteriostatic, inhibitory drug concentrations are much lower than bactericidal drug concentrations. In general, cell wall-active agents are bactericidal, and drugs that inhibit protein synthesis are bacteriostatic. 

After the selection of a suitable test organism, the strategy of mode of action studies involves basically the testing of the compound under study for its effects on each of the five processes listed above. This requires invariably the study of actively growing cultures or, better, of organisms which are incubated in a medium which supports growth and multiplication. Bactericidal drugs, for example, penicillin... 

High doses of bactericidal drugs are needed because the organisms are difficult to access in avascular vegetations on valves and the protective host reaction is negligible. 

Impaired immune responses render the subject more liable to bacterial and viral infections. Treat all infection early and vigorously (using bactericidal drugs where practicable) use human gamma globulin to protect if there is exposure to virus infections, e.g. measles, varicella. For example, patients who have not had chickenpox and are receiving therapeutic (as opposed to replacement) doses of corticosteroid are at risk of severe chickenpox they should receive varicella-zoster immunoglobulin if there has been contact with the disease within the previous 3 months. 

Bactericidal drugs irreversibly damage and kill bacteria, usually by attacking the cell wall or plasma membrane (e.g. penicillins, cephalosporins, polymyxins). 

Bactericidal drug that acts at an early stage in cell-wall synthesis, binding at the D-ala-D-ala pentapeptide to sterically hinder the transglycosylation reactions involved in elongation of pep-tidoglycan chains. 

Bacteriostatic antibiotics inhibit bacterial growth and proliferation, while bactericidal antibiotics actually kill bacteria. Many antibiotics are bacteriostatic at low concentrations and bactericidal at higher concentrations. This distinction is often not important clinically. If bacteria are prevented from multiplying, they will eventually be destroyed by the normal immune reaction of the host. Infections in inmiunocompromized individuals (for example, those with human immunodeficiency virus (HIV) infection and those on systemic corticosteroid, anticancer or immunosuppressant therapy) have to be treated with potent bactericidal drugs. 

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 bactericidal drug kills the bacteria directly, by eliminating a necessary means of survival (e.g., disruption of the cell wall). 

List possible mechanisms of action for a bactericidal drug. 

C. Mechanisms of Action and Resistance Beta-lactam antibiotics are bactericidal drugs. They act to inhibit cell wall synthesis by the following steps (Figure 43 2) (1) binding of the drug to specific receptors (penicillin-binding proteins PBPs) located in the bacterial cytoplasmic membrane (2) inhibition of transpeptidase enzymes that act to cross-link linear peptido-glycan chains which form part of the cell wall and (3) activation of autolytic enzymes that cause lesions in the bacterial cell wall. 

Table 7.1 Bactericidal Drugs that Work at the Cell Wall ...

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