Penicillins Antimicrobial agents

Therefore, despite the 18% and 25% resistance to penicillin and macrolides, the clinical failure rate is less than this. Owing to the empirical treatment of CAP in the outpatient setting, establishing a meaningful clinical failure rate with any therapy is difficult to do. No studies have been performed that established a correlation between clinical failure rates with a particular antimicrobial agent and the percentage of resistant bacterial pathogens. 

Bjomeklett A, Midvedt T Influence of three antimicrobial agents - penicillin, metronidazole and doxycyclin - on the intestinal microflora of healthy humans. Scand J Gastroenterol 1988 94 928-932. 

Penicillin antibiotics must be used with caution because some strains of Bacillus anthracis possess an enzyme that inactivates penicillin. Other antimicrobial agents can be used as alternatives if the listed drugs are unavailable or in short supply. These include erythromycin, imipenem, clindamycin, vancomycin, and chloramphenicol.3... 

Mastitis is nearly always caused by bacterial infection. The introduction of benzyl penicillin for the treatment of intramammary infections (IMI) caused by Gram positive bacteria, followed by products containing other antimicrobial agents, was a major advance in... 

In the treatment of infections caused by E aeruginosa, the antimicrobial agent that has proved to be effective is Penicillin G Piperacillin Nafcillin Erythromycin Tetracycline... 

Other antimicrobial agents used in urinary tract infection e.g. sulfonamides, quinolones, penicillins, ... 

Antimicrobial agents— Certain antimicrobial agents e.g. penicillin, bacitracin, aeuromycin etc. are being used to reduce the bacterial count which may be beneficial in reducing the incidence of dental caries. 

In this chapter, the latest applications published in the literature from 1994 to 1998 are reviewed. The following groups of antimicrobial agents are discussed tetracyclines, penicillins, poiyethers, aminoglycosides, macrolides, amphenicols, nitrofurans, sulphonamides, quinolones and other antimicrobials. 

Enzymic inactivation The ability to destroy or inactivate the antimicrobial agent also can confer resistance on microorganisms. For example, (3-lactamases destroy many penicillins and cephalosporins and an acetyltransferase can convert chloramphenicol to an inactive compound. 

Church D, et al. Efficacy of moxifloxacin in the treatment of acute bacterial sinusitis caused by penicillin-resistant Streptococcus pneumoniae. In 40th Interscience Conference on Antimicrobial Agents and Chemotherapy, Abstract 833. Toronto, 2000. 

Three words (resistance, insusceptibility, tolerance) and their corresponding adjectives find widespread use, often interchangeably, to signify the lack of effect of an antimicrobial agent on a microbial cell. Tolerance is usually used to denote lack of lysis in some penicillin-treated streptococci. Resistance in terms of insusceptibility to biocides is often used to denote an in-... 

The anhydropenicillin (49) [50-52] may also be classified as a derivative containing an exocyclic double-bond. This compound is often cited as a typical instance contradicting the lability of )3-lactams, a misbelief descending from the early period of penicillin chemistry. Penicillin G is indeed labile in aqueous solutions, but there is also much evidence as to the stability of other /3-lactam compounds. The anhydropenicillin can undergo melting without decomposition. It is ineffective as an antimicrobial agent. 

In the case of successful antimicrobial agents, altering metabolic processes unique to microorganisms, e.g. penicillin interferes with formation of the bacterial cell wall, or by showing enormous quantitative differences in affecting a process common to both humans and microbes, e.g. inhibition of folic acid s5mthesis by trimethoprim. 

Naturally resistant strains. Some bacteria are innately resistant to certain classes of antimicrobial agent, e.g. coliforms and many other Gramnegative bacteria possess outer cell membranes which protect their cell walls from the action of certain penicillins and cephalosporins. Facultatively anaerobic bacteria (such as Escherichia colt) lack the ability to reduce the nitro group of metronidazole which therefore remains in an inactive form. In the course of therapy, naturally sensitive organisms are eliminated and those naturally resistant proliferate and occupy the biological space newly created by the drug. 

Mandell, G. L. Petri, W. A. Antimicrobial Agents Penicillins, Cephalosporins and Other P-Lactam Antibiotics. In Goodman and Gilman s The Pharmacological Basis of Therapeutics, Hardman, J. C., Limbird, L. E., Eds. McGraw-Hill New York, 1996. 

Pseudomembranous colitis was known before the introduction of antimicrobial agents and can still occur without previous antibiotic use, for example after antineoplastic chemotherapy (125) or even spontaneously. However, the number of cases has increased dramatically since antibiotics began to be used (126). Patients treated with lincomycin or clindamycin, cephalosporins, penicillinase-resistant penicillins, or combinations of several antibiotics... 

Available studies suggest that penetration of the newer quinolones into all extravascular sites (large-volume spaces i.e., ascites, pleural fluid, etc.), secretory fluids (urine, prostatic secretions, sputum, etc.), barrier fluids (CSFL), and whole tissues is high relative to the penetration reported for most other categories of antimicrobial agents, particularly, the penicillins, cephalosporins, and aminoglycosides... 

Penicillin antibiotics are part of a wide variety of antimicrobial agents that are used as veterinary drugs to prevent and treat infectious diseases. Such use may lead to problems with residues in the livestock products. To provide safe products for consumers, the quantification of these residues in foods is required. 

Much of the use of antimicrobial agents is irrational. Antimicrobial therapy for superficial wounds and single doses of penicillin administered after the elective castration of normal horses has no real therapeutic benefit and encourages antimicrobial resistance. 

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