Bacteriostatic activity

Specific bacteriostatic activity against Escherichia coli (681, 896, 899), Staphylococcus aureus (681, 896), Cocci (900), Shigella dysenteriae (681), Salmonella ryphi (681), Proteus vulgaris (681), Pseudomonas aeruginosa (681), Streptococcus (889, 901, 902) and Pneumococcus (901-904). 

Sucrose monoesters (SMEs) are used as nonionic surfactants, in detergents and as emulsifiers in foods. Some SMEs have bacteriostatic activity and are used to prevent spoilage in beverages. Semperfresh, an SME produced in the U.K., is used as a coating to extend the shelf life of fmits and vegetables (21,29). 

Whereas these preparations do not possess the high bacteriostatic activity of quaternary ammonium germicides, they have the alternate advantage of being rapidly functional in acid solution. In comparative experiments of several different disinfectants, the acid—anionic killed bacteria at lower concentration than five other disinfectants. Only sodium hypochlorite and an iodine product were effective at higher dilution than the acid—anionic. By the AO AC use dilution test, the acid—anionic killed Pseudomonas aeruginosa at 225 ppm. Salmonella choleraesuis at 175 ppm, and Staphylococcus aureus at 325 ppm (172). 

Number and type of organism Bacteriostatic activity, ppm Bactericidal activity, log reduction... 

Pterin, 6-hydroxymethyl-7,7-dimethyl-7,8-dihydro-bacteriostatic activity, 3, 325 Pterin, 1-methyl-hydrolysis, 3, 294 5-oxide... 

The sulfonamides are primarily bacteriostatic, which means they slow or retard the multiplication of bacteria This bacteriostatic activity is due to sulfonamide antag-... 

The penicillins may be bactericidal (destroy bacteria) or bacteriostatic (slow or retard the multiplication of bacteria). They are bactericidal gainst sensitive microorganisms (ie, those microorganisms that will be affected by penicillin) provided there is an adequate concentration of penicillin in the body. An adequate concentration of any drug in the body is referred to as the blood level. An inadequate concentration (or inadequate blood level) of penicillin may produce bacteriostatic activity, which may or may not control the infection. 

Trimethoprim (Trimpex) interferes with the ability of bacteria to metabolize folinic acid, thereby exerting bacteriostatic activity. Trimethoprim is used for UTIs that are caused by susceptible microorganisms. Trimethoprim administration may result in rash, pruritus, epigastric distress, nausea, and vomiting. When trimethoprim is combined with sulfamethoxazole (Septra), the adverse effects associated with a sulfonamide may also occur. The adverse reactions seen with other anti-infectives, such as ampicillin, the sulfonamides, and cephalosporins, are given in their appropriate chapters. 

Effect of surface activity 4.1 Tests for bacteriostatic activity... 

Table 37.3 shows the complete table of eight indicator variables for 10 triply substituted tetracyclines [31 ] that have been tested for bacteriostatic activity (1/Z), which is defined here as the ratio of the number of colonies grown with a substituted and with the unsubstituted tetracycline. In this application we have three substitution positions, labelled U, V and W. The number of substituents at the three sites equals 2,3 and 3, respectively. Arbitrarily, we chose the compound with substituents H, NOj and NO2 at the sites U, V and W as the reference compound. This leads to a reduction of the number of indicator variables from eight to five, as shown in Table 37.4. The solution of the Free-Wilson model can be obtained directly by means of multiple regression ...

Complete indicator table and bacteriostatic activities of 10 triply substituted tetracyclines. The three substitution positions are labeled U, V and W [31]. 

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... 

Lincomycins bacteriostatic activity is based on the inhibition of the bacterial proteic synthesis. Lincomycin A in particular have been largely employed in clinical therapy of infections caused by micoplasmas, Gram-positive bacteria, and cocci but it presents a lot of side effects overcome by 7-clindamycin (Fig. 21), a semi-synthetic drug with larger spectrum of action and major antibacterial activity. 

The hexitol anhydrides also have medicinal uses.97 Carr and Krantz98 found that l,4 3,6-dianhydro-D-mannitol was quite non-toxic to man and was a valuable diuretic. The dinitrates of both isomannide and isosorbide" have possible uses as agents for lowering blood pressure, though Burn and Stephenson100 found that the D-sorbitol derivative was twice as active as the D-mannitol derivative in this respect. 2,5-Diam-ino-2,5-didesoxy-l,4 3,6-dianhydro-D-mannitol and -D-sorbitol have been prepared and their sulfanilamido derivatives obtained.101 These however showed no outstanding bacteriostatic activity. 

Trimethoprim inhibits bacterial DHF reductase, the human enzyme being significantly less sensitive than the bacterial one (rarely bone marrow depression). A 2,4-diaminopyrimidine, trimethoprim, has bacteriostatic activity against a broad spectrum of pathogens. It is used mostly as a component of co-trimoxazole. 

Qiloramphenicol inhibits peptide synthetase. It has bacteriostatic activity against a broad spectrum of pathogens. The chemically simple molecule is now produced synthetically. 

Dapsone, which was first proposed in 1941, possesses both bactericidal as weU as bacteriostatic activity with respect to Mycobacterium leprae and Mycobacterium tuberculosis. It is used to treat patients with herpetiform dermatitis. It is believed that the mechanism of its action consists of competitive inhibition of the enzyme dihydroprotease synthetase, which blocks synthesis of folic acid in microorganisms, allowing it to also be viewed as an analog of p-aminobenzoic acid. Synonyms of this drug are avosulfon, croysulfon and others. 

The demonsfrafion fhaf fhe bacteriostatic activity of lactoferrin can be independenf of fhe level of iron saturation (Arnold et ah, 1980) suggests that lactoferrin has ofher antimicrobial mechanisms. Lactoferrin has been... 

Fusidic acid is a product of, among others, the fungus Fusidium coccineum. It has a steroidal structure and has mainly bacteriostatic activity. Its mechanism of action is based on inhibition of bacterial protein synthesis. Its indications are limited to the treatment of severe staphylococcal infections, usually in combination with another antistaphylococcal agent to prevent the emergence of resistance. 

Benzoyl peroxide is a keratolytic drug. It has bacteriostatic activity against Propionibacterium acnes. Initial irritation is common. Rarely, contact sensitivity occurs. Potassium permanganate is used for the same indications. 

Triclosan also has a broad-range bacteriostatic activity against gram-positive and gram-negative bacteria, fungi, molds, and yeasts. It is metabohzed to its glucuronide... 

Mechanism of Action Anantituhercular agent active against Mycobackrium tuberculosis. Thought to exhibit competitive antagonismoffolicacid synthesis. Therapeutic Effect Bacteriostatic activity in susceptible microorganisms. 

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. 

Tetracycline Prevents bacterial protein synthesis by binding to the 30S ribosomal subunit Bacteriostatic activity against susceptible bacteria Infections caused by mycoplasma, chlamydiae, rickettsiae, some spirochetes malaria H pylori acne Oral mixed clearance (half-life 8 h) dosed every 6 h divalent cations impair oral absorption Toxicity Gastrointestinal upset, hepatotoxicity, photosensitivity, deposition in bone and teeth... 

Chloramphenicol Prevents bacterial protein synthesis by binding to the 50S ribosomal subunit Bacteriostatic activity against susceptible bacteria Use is rare in the developed world because of serious toxicities Oral, IV hepatic clearance (half-life 2.5 h) dosage is 50-100 mg/kg/d in four divided doses Toxicity Dose-related anemia, idiosyncratic aplastic anemia, gray baby syndrome... 

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