Antibacterial effect

P-lactam antibiotics, exert thek antibacterial effect by interfering with the synthesis of the bacterial cell wall. These antibiotics tend to be "kreversible" inhibitors of cell wall biosynthesis and they are usually bactericidal at concentrations close to thek bacteriostatic levels. Cephalospotins are widely used for treating bacterial infections. They are highly effective antibiotics and have low toxicity. 

The antibacterial effectiveness of penicillins cephalospotins and other P-lactam antibiotics depends upon selective acylation and consequentiy, iaactivation, of transpeptidases involved ia bacterial ceU wall synthesis. This acylating ability is a result of the reactivity of the P-lactam ring (1). Bacteria that are resistant to P-lactam antibiotics often produce enzymes called P-lactamases that inactivate the antibiotics by cataly2ing the hydrolytic opening of the P-lactam ring to give products (2) devoid of antibacterial activity. 

P-Lactam antibiotics exert their antibacterial effects via acylation of a serine residue at the active site of the bacterial transpeptidases. Critical to this mechanism of action is a reactive P-lactam ring having a proximate anionic charge that is necessary for positioning the ring within the substrate binding cleft (24). 

Resorcinol unclogs pores by causing dead skin cells to slough off. It also has antifungal and antibacterial effects. 

Phillips, L.G. and Barbano, D.M., The influence of fat substitutes based on protein and titanium dioxide on the properties of low fat milks, J. Dairy Sci., 80, 2726, 1997. Choi, J.Y. et ah, Photocatalytic antibacterial effect of TiOj film formed on Ti and TiAg. J. Biomed. Mater. Res. B Appl. Biomater., epub., 2006. 

Some of the N-alkylated narceine amides and imides were tested for antibacterial effectiveness and showed activity of medium potency against Mycobacterium tuberculosis H37 Rv. Their antimycotic activity was also of medium strength. Coccidiostatic screening showed some effectiveness (100). 

By screening 53 Rhodococcus and Pseudomonas strains, an NHase-amidase biocatalyst system was identified for the production of the 2,2-dimethylcyclopropane carboxylic acid precursor of the dehydropeptidase inhibitor Cilastatin, which is used to prolong the antibacterial effect of Imipenem. A systematic study of the most selective of these strains, Rhodococcus erythropolis ATCC25 544, revealed that maximal product formation occurs at pH 8.0 but that ee decreased above pH 7.0. In addition, significant enantioselectivity decreases were observed above 20 °C. A survey of organic solvent effects identified methanol (10% v/v) as the... 

Bismuth subsalicylate is often used for treatment or prevention of diarrhea (traveler s diarrhea) and has antisecretory, antiinflammatory, and antibacterial effects. Bismuth subsalicylate contains multiple components that might be toxic if given in excess to prevent or treat diarrhea. 

Epithelial cells in the skin Some of the lactic acid produced by glycolysis is secreted in perspiration. It lowers the pH of the surface of the skin, where it has an antibacterial effect. The concentration on the surface may be as high as 15 mmol/L. 

One mechanism by which fever has an antibacterial effect is that it decreases the blood concentration of iron, which is necessary for bacterial proliferation (Chapter 17). However, iron is also necessary for the proliferation of immune cells in the lymph nodes and in the bone marrow (for formation of the iron-containing proteins, haemoglobin and mitochondrial proteins). This leads to competition for iron in the... 

Macgowan AP, Bowker KE, Noel AR. (2008) Pharmacodynamics of the antibacterial effect and emergence of resistance to tomopenem, formerly RO4908463/CS-023, in an in vitro pharmacokinetic model of Staphylococcus aureus infection. Antimicrob Agents Chemother 52 1401-1406. 

Kusuda M, Inada K, Ogawa TO, Yoshida T, Shiota T, Shiota S, Tsuchiya T, Hatano T. (2006) Polyphenolic constituents structures of Zanthoxylum piper-itum fruit and the antibacterial effects of its polymeric procyanidin on methicillin-resistant Staphylococcus aureus. Biosci Biotechnol Biochem 70 1423-1431. 

Antibiotics are commonly added to many livestock feeds at "subtherapeutic levels, defined usually as up to 200 parts per million, commonly expressed as 200 grams per ton. This increases growth and suppresses bacteria that cause certain diseases, some of them subacute. The increase in growth results from an antibacterial effect. 

Co-trimoxazole is a combination of trimethoprim and the sulfonamide sulfamethoxazole. Since THF synthesis is inhibited at two successive steps, the antibacterial effect of co-trimoxazole is better than that of the individual components. Resistant pathogens are infrequent a bactericidal effect may occur. Adverse effects correspond to those of the components. 

Mycobacteria are responsible for two diseases tuberculosis, mostly caused by M. tuberculosis, and leprosy due to M. leprae. The therapeutic principle applicable to both is combined treatment with two or more drugs. Combination therapy prevents the emergence of resistant mycobacteria Because the antibacterial effects of the individual substances are additive, correspondingly smaller doses are sufficient Therefore, the risk of individual adverse effects is lowered. Most drugs are active against only one of the two diseases. 

Like other semisynthetic penicillins, methicillin exhibits an antibacterial effect similar to that of benzylpenicillin. The main difference between methicillin and benzylpenicillin is that it is not inactivated by the enzyme penicillinase, and therefore it is effective with respect to agents producing this enzyme (staphylococci). It is used for infections caused by benzylpenicillin-resistant staphylococci (septicemia, pneumonia, empyemia, osteomyelitis, abscesses, infected wounds, and others). Synonyms of this drug are cinopenil, celbenin, staphcillin, and others. 

Rifampicin exhibits an antibacterial effect by inhibiting RNA synthesis. It inhibits DNA-dependent RNA polymerase by preventing the initial development of the chain, not by removing it. Rifampicin does not bind with the RNA polymerase nucleus of mam-maliam cells, and does not have an effect on corresponding RNA synthesis. It can inhibit mitochondrial RNA synthesis however, concentrations required for this exceed those necessary for synthesizing RNA by several hundred times. 

B) Fleming discovering the antibacterial effect of penicillium notatum... 

Lunestad B.T. and J. Gokspyr (1990). Relaxation in the antibacterial effect of ox)4etracycline in sea water by complex formation with magnesium and calcium. Diseases of Aquatic... 

Due to the antimicrobial activity of many of the phenolic compounds against different bacterial and fungal strains, several reports about the antibacterial effects of C-glycosylfla-vones have appeared. 

Michael, H.N., Guergues, S.N., and Sandak, R.N., Some polyphenolic constituents of Titricum aestivum (wheat bran, Sakha 69) and their antibacterial effect, Asian J. Chem., 10, 256, 1998. 

Antifungal/antibacterial effect of cotton fabric surface for A. niger, P. phoeniceum and S. aureus has been confirmed even at as low nanosilver concentration as 1 pgcm . The same experiments conducted for E. coli, B. subtilis and A. pullulans cultures also demonstrated a pronounced antimicrobial effect at concentrations of nanosilver of 7 pgcm, 5 pgcm" and 3 pgcm" respectively. 

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