Antimicrobial agents sulfonamides

Mandell, G.L. Sande, M.A. Antimicrobial agents sulfonamides, trimethoprim, sulfamethoxazole, quinolones, and agents for urinary tract infections. In Pharmacological Basis of Therapeutics, 8th Ed. Gilman, A.G., Rail, T.W., Nies, A.S., Taylor, P., Eds. Pergamon Press New York, 1991 1047-1064. 

Host factors can help to ensure selection of the most appropriate antimicrobial agent. Age is an important factor in antimicrobial selection. With regard to dose and interval, renal and hepatic function varies with age. Populations with diminished renal function include neonates and the elderly. Hepatic function in the neonate is not fully developed, and drugs that are metabolized or eliminated by this route may produce adverse effects. For example, sulfonamides and ceftriaxone may compete with bilirubin for binding sites and may result in hyperbilirubinemia and kernicterus. Gastric acidity also depends on... 

Antimicrobial acrylic fibers, 11 215-219 Antimicrobial agents, 12 31. See also Antimicrobial compounds in continuous-filament yarns, 19 758 as preservatives, 12 57-59 silylating agents and, 22 700 as soap bar additives, 22 746 sulfonamides as, 23 494 Antimicrobial compounds, microbiological methods for determining, 20 132 Antimicrobial nanoemulsion technology, 3 630-631... 

Sulfasalazine is absorbed in the proximal intestine and is then excreted unchanged in the bile. In consequence most of orally administred sulfasalzine reaches the colon as such. It is then split by the intestinal flora into its components sulfapyridine, a sulfonamide antimicrobial agent, and 5-aminosalicylic acid (5-ASA). It has been proven that in inflammatory bowel disease 5-ASA is responsible for the beneficial effects while the sulpha component only contributes to the adverse reaction profile. Although some 5-ASA is absorbed and excreted in urine with a half-life of 0.5-1.5 hours, most is eliminated unchanged in the faeces. Sulfapyridine is to a major extend reabsorbed, metabolized in the liver and excreted in the urine with a half-life, depending on the acetylator phenotype, between 5 and 15 hours. 

Because of development of resistance and availability of more advanced antimicrobial agents, the use of sulfonamides is limited. However they are used in combination with trimethoprim. The important therapeutic uses are ... 

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

Gerhard Domagk, German pathologist and Nobel prize winner, observed the antibacterial property of a prototypical sulfonamide (Prontosil) that is considered to be the first selective antimicrobial agent... 

The sulfonamides are a group of organic compounds with chemotherapeutic activity they are antimicrobial agents and not antibiotics. They have a common chemical nucleus that is closely related to PABA, an essential component in the folic acid pathway of nucleic acid synthesis. The sulfonamides are synergistic with the diaminopyrim-idines, which inhibit an essential step further along the folate pathway. The combination of a sulfonamide and a diaminopyrimidine is advantageous because it is relatively non-toxic to mammalian cells (less sulfonamide is administered) and is less likely to select for resistant bacteria. Only these so-called potentiated sulfonamides are used in equine medicine. These drugs are formulated in a ratio of one part diaminopyrimidine to five parts sulfonamide, but the optimal antimicrobial ratio at the tissue level is 1 20, which is achieved because the diaminopyrimidines are excreted more rapidly than the sulfonamides. 

The treatment of choice for coccidiosis is the sulfonamide antimicrobial agents (see Ch. 2). The sulfonamides disrupt folic acid and nicotinamide metabolism and coenzymes I and II by competing with para-aminobenzoic acid (PABA). Coccidia must manufacture their own folic acid and, therefore, this step is mandatory in the pyrimidine pathway of these parasites. Sulfamethazine (sulfadimidine) at 220mg/kg i.v. or orally, or sul-fadimethoxine (55mg/kg) orally or sulfathiazole (66mg/kg) orally, all once daily for 5-7 days, are used commonly for the treatment of equine coccidiosis. The signs of toxicity of the sulfonamides are covered extensively in Chapter 2. Crystalluria,... 

The gastrointestinal tract is a frequent site for adverse effects of antimicrobial drugs, primarily because of disruption of normal intestinal microbial populations and proliferation of enteropatho-gens. Diarrhea, often with accompanying signs of endotoxemia, is the usual clinical manifestation. Antimicrobial agents known to be, or implicated in being, associated with antimicrobial-induced diarrhea include penicillin, ceftiofur, lincomycin, tetracycline, erythromycin and the potentiated sulfonamides. Erythromycin can also promote diarrhea via its motilide activity. 

It warrants mention that resistance to a particular antimicrobial agent in vitro may not preclude successful treatment with the drug as long as high concentrations are achieved in urine. Similarly, demonstrable susceptibility in vitro does not always guarantee a successful response to treatment. For example. Enterococcus spp. is often found to be susceptible to the potentiated sulfonamide combinations in vitro however, this pathogen is inherently resistant to these combinations in vivo (Jose-Cunilleras Hinchcliff 1999, Schott 1998). Antimicrobial therapy should be continued for at least 1 week for the treatment of lower UTIs and for 2-6 weeks for upper UTls in horses. Ideally, a voided, midstream urine sample should be submitted for bacterial culture 2-4 days after the initiation of therapy and again 1-2 weeks after treatment has been discontinued. 

Amlnocyclitols in general, and spectinomycin in particular, are effective in no more than half the patients with NGU, an observation that correlates with the fact that U. urealyticum is susceptible but C. trachomatis is not. Conversely, sulfonamide therapy is successful in chlamydial NGU, but not in NGU associated with U. urealyticum. The differential response to sulfisoxazole or spectinomycin has been used to differentiate chlamydial from ureaplasmal NGU, and a combination of these two agents deserves a clincial trial as an alternative to the tetracyclines. C. trachomatis and U. urealyticum are individually susceptible to several other antimicrobial agents,but all are clinically ineffective or have not been subjected to controlled studies. 

The lactating female can pass antimicrobial agents to her nursing child. Both nalidixic acid and the sulfonamides in breast milk have been associated with hemolysis in children with glucose-6-phosphate dehydrogenase deficiency, hi addition, sulfonamides, even in the small amounts received from breast milk, may predispose the nursing child to kemicterus. 

Penicillins Cephalosporins and Cephamycins Tetracyclines Aminoglycosides Sulfonamides Erythromycin, Its Salts, and Esters Other Antimicrobial Agents. 

Uses antibacterial agent and antimicrobial agent of sulfonamide type (topical and vaginal)... 

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