Antibiotics bacteriostatic activity

Antimicrobials also can be classified as possessing bactericidal or bacteriostatic activity in vitro. Bactericidal antibiotics generally kill at least 99.9% (3 log reduction) of a bacterial population, whereas bacteriostatic antibiotics possess antimicrobial activity but reduce bacterial load by less than 3 logs. Clinically, bactericidal antibiotics may be necessary to achieve success in infections such as endocarditis or meningitis. A full discussion of the application of antimicrobial pharmacodynamics is beyond the scope of this chapter, but excellent sources of information are available.15... 

The bacteriostatic activity which is inhibition of growth and multiplication of bacteria and bactericidal activity, which is bacterial death, is induced by certain types of antibiotics. Cytotoxic action is selective for invading cancer cells and altering them without affecting the host cells. 

Chloramphenicol, a broad spectrum antibiotic, is active not only against bacteria but also against other microorganisms, such as rickettsiae. Chloramphenicol has excellent activity against anaerobes. The drug is either bactericidal or (more commonly) bacteriostatic, depending on the organism. 

Streptomycin was inactivated by reducing and oxidizing agents. The bacteriostatic-activity of this antibiotic for Escherichia coli was reduced in the presence of cysteine, sodium thioglycolate, stannous chloride, sodium bisulfite, sodium hydrosulfide, sodium formate and sodium thiosulfate. Cysteine was the most active. Denkelwater, Cook and Tishler found that the cysteine inactivation of streptomycin could be reversed by iodine presumably cystine was formed during this process. Rake and Donovick inactivated streptomycin with semi-carbazide hydrochloride in order to test the sterility of concentrated streptomycin solutions. The inactivation of streptomycin by compounds containing sulfhydryl groups has been discussed by Cavallito. ... 

HOST FACTORS A critical determinant of antibiotic efficacy is the status of the host humoral and cellular defense mechanisms. In the immunocompetent host, merely halting the multiplication of the microorganism with a bacteriostatic agent frequently is sufficient to cure the infection. If host defenses are impaired, bacteriostatic activity may be inadequate and a bactericidal agent is required for cure. Examples where this applies include bacterial endocarditis, bacterial meningitis, and disseminated bacterial infections in nentropenic patients. Patients with HIV-1 infection and acquired immunodeficiency syndrome have impaired cellular immune responses. Therapy for opportunistic infection therefore often is snppressive bnt not cnrative disseminated infections with Salmonella or atypical mycobacteria typically require prolonged antibiotic therapy to prevent relapse. 

Lincosamide antibiotic bacteriostatic inhibitor of protein synthesis (50S) active against gram-positive cocci, B fragilis. Tox GI distress, pseudomembranous colitis. 

Actinorhodin (ACT) belongs to a class of aromatic antibiotics (benzoisochromane-quinones, BIQs), and is a red pigment produced by 5. coelicolor A3(2), with weak bacteriostatic activity against Staphylococcus aureus [182]. The BIQ antibiotics showed a trans confguration with respect to the C-3 and C-15 chiral centers (35,15R or 3R,155). ACT represents the former type the opposite stereochemistty is exemplified by granaticin (GRA) produced by Streptomyces violaceoruber (Figure 6.38) [183]. 

When peeling off the face, herpes simplex reactivation is less likely and antiviral prophylaxis is not required. Due to the fact that all of the peeling agents have some degree of bacteriostatic activity, jxistprocedural antibiotics are not routinely prescribed. 

Production of antagonistic compounds Several probiotics have been selected for their ability to produce compounds that are inhibitory towards the proliferation of (opportunistic) pathogens (Verschuere et al, 2000). In that way, they can be considered to be natural antibiotics. The bactericidal or bacteriostatic activity can mostly be ascribed to the production of bacteriocins, lysozymes, hydrogen peroxide, carbon dioxide or siderophores and/or the alteration in pH by the production of organic acids (Verschuere et al, 2000 Vine et al., 2006). TTie production of antagonistic compounds is a common trait for both marine and... 

Antibiotics possess antibacterial activity and are used in the treatment of eye infections. Sulfonamides possess a bacteriostatic effect against a wide range of gram-positive and gram-negative microorganisms. They are used in the treatment of conjunctivitis, comeal ulcer, and other superficial infections of the eye. See the Summary Drug Table Select Ophthalmic Preparations and Chapter 6 for additional information on the sulfonamides. 

Studies to elucidate the mode of bacteriostatic property of xanthostatin (XS), a novel depsipeptide antibiotic with an A/-acetylglydne side chain and selective antimicrobial activity against Xanthomonas spp., were carried ont by Kim and coworkers [80]. Two biotransformed XSs were isolated by the treatment of XS with the cell... 

Lincosamides (lincomycin and clindamycin) are representatives of a very small group of drugs synthesized up of an amino acid bound to an amino sugar. Lincosamides bind with the 50 S ribosomal subunit of bacteria and inhibit protein synthesis. They also inhibit pep-tidyltransferase action. Lincosamides are bacteriostatic antibiotics however, when they reach a certain level in the plasma, they also exhibit bactericidal action against some bacteria. Lincosamides are highly active against anaerobic infections such as Peptococcus, Peptostreptococcus, Actinomyces, Propionibacterium, and Clostridium fringens, a few types of Peptococcus and Clostridium. 

B. Humans cannot synthesize folic acid (A) diet is their main source. Sulfonamides selectively inhibit microbially synthesized folic acid. Incorporation (B) of PABA into microbial folic acid is competitively inhibited by sulfonamides. The TMP-SMX combination is synergistic because it acts at different steps in microbial folic acid synthesis. All sulfonamides are bacteriostatic. Inhibition of the transpeptidation reaction (C) involved in the synthesis of the bacterial cell wall is the basic mechanism of action of (3-lac-tam antibiotics Changes in DNA gyrases (D) and active efflux transport system are mechanisms for resistance to quinolones. Structural changes (E) in dihydropteroate synthetase and overproduction of PABA are mechanisms of resistance to the sulfonamides. 

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