Other antibiotics

CHLORAMPHENICOL ANTICANCER AND IMMUNOMODULATING DRUGS-TACROLIMUS Toxic blood levels of tacrolimus, usually on the second day of starting chloramphenicol Attributed to impaired clearance of tacrolimus by chloramphenicol 1 dose of nearly 80% of tacrolimus may be required to prevent toxicity. Watch for adverse effects (see below). Monitor tacrolimus plasma concentrations 

CHLORAMPHENICOL ANTICOAGULANTS-ORAL Occasional episodes of t anticoagulant effect Uncertain at present Monitor INR every 2-3 days 

CHLORAMPHENICOL ANTIDIABETIC DRUGS-SULPHONYLUREAS Possibly 1 hypoglycaemic effect of sulphonylureas Mechanism uncertain. Chloramphenicol is an inhibitor of CYP3A4 Be aware 

DRUGS TO TREAT INFECTIONS OTHER ANTIBIOTICS Chloramphenicol 

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Tolypomycin Y (48) shows strong antibacterial activity against gram-positive bacteria and Neisseriagonorrheae. When adininistered by subcutaneous, intraperitoneal, and intravenous routes, tolypomycin Y is effective in mice infected with Staphylococcus aureus Streptococcuspyrogenes and Diplococcuspneumoniae. Cross-resistance is observed with rifampicia but not with other antibiotics. Resistance to tolypomycin Y develops rapidly. The bioactivity of tolypomycin R... 

Veterinary Potential or Fiorfenicol. The absolute ban on the use of chloramphenicol ia food producing animals ia the United States and Canada has accentuated the need for an effective broad spectmm antibiotic ia animal food medicine. Fiorfenicol and other antibiotics commonly used ia veterinary medicine have been evaluated in vitro against a variety of important veterinary and aquaculture pathogens. Some of these data ate shown in Tables 4 and 5, respectively. Fiorfenicol was broadly active having MICs lower than those of chloramphenicol in each of the genera tested (Table 4). Florfenicol was also superior to chloramphenicol, thiamphenicol, oxytetracycline [79-57-2] ampicillin [69-53-4] and oxolinic acid [14698-29-4] against the most commonly isolated bacterial pathogen of fish in Japan (Table 5) (37). 

Table 5. Minimum Inhibitory Concentrations (MIC q ) of Florfenicol (2) and Other Antibiotics Against Bacterial Pathogens Isolated from Fish in Japan, Jg/mL...

Although the antibacterial spectmm is similar for many of the sulfas, chemical modifications of the parent molecule have produced compounds with a variety of absorption, metaboHsm, tissue distribution, and excretion characteristics. Administration is typically oral or by injection. When absorbed, they tend to distribute widely in the body, be metabolized by the Hver, and excreted in the urine. Toxic reactions or untoward side effects have been characterized as blood dyscrasias crystal deposition in the kidneys, especially with insufficient urinary output and allergic sensitization. Selection of organisms resistant to the sulfonamides has been observed, but has not been correlated with cross-resistance to other antibiotic families (see Antibacterial AGENTS, synthetic-sulfonamides). 

Bacitracin given parenteraHy is sufftciendy nephrotoxic that it is rarely used in human medicine for other than topical indications (80). Thus safe and effective use, especially as the zinc salt, is limited almost completely to ointments, sprays, and solutions for skin and ophthalmic use in concentrations of 250 to 1000 units per milliliter. Bacitracin is only rarely skin sensitizing. As in the case of polymyxin, bacitracin is usually combined with other antibiotics to enlarge its spectmm of activity, or with corticoids or analgesics to reUeve pain or itching. 

The commercial production of penicillin and other antibiotics are the most dramatic in industrial microbiology. The annual production of bulk penicillin is about 33 thousand metric tonnes with annual sales market of more than US 400 million.8 The worldwide bulk sales of the four most important groups of antibiotics, penicillins, cephalosporins, tetracyclines and erythromycin, are US 4.2 billion per annum.10... 

The clinical aspects of several antibiotics such as penicillin G, cephalosporin and many other antibiotics are summarised in Table 11.1. The potential microorganisms for the production of various antibiotics and then activities on site or mode of action of the antibiotics are also listed. 

The sulfonamides (sulfa) drug s were the first antibiotic dragp developed that effectively treated infections. Although the use of sulfonamides began to decline after the introduction of more effective anti-infectives, such as the penicillins and other antibiotics, these drug s still remain important for the treatment of certain types of infections. 

These antibiotics are effective in the treatment of infections caused by a wide range of gram-negative and gram-positive microorganisms. The lincosamides are used for the more serious infections. In serious infections they may be used in conjunction with other antibiotics. 

Other antibiotics inhibit protein synthesis on all ribosomes (puromycin) or only on those of eukaryotic cells (cycloheximide). Puromycin (Figure 38—11) is a structural analog of tyrosinyl-tRNA. Puromycin is incorporated via the A site on the ribosome into the carboxyl terminal position of a peptide but causes the premature release of the polypeptide. Puromycin, as a tyrosinyl-tRNA analog, effectively inhibits protein synthesis in both prokaryotes and eukaryotes. Cycloheximide inhibits peptidyltransferase in the 60S ribosomal subunit in eukaryotes, presumably by binding to an rRNA component. 

Employed as a sodium salt, fusidic acid (Fig. 5.14B) is achve against many types of Gram-positive bacteria, especially staphylococci, although streptococci are relatively resistant. It is employed in the treatment of staphylococcal infections, including strains resistant to other antibiotics. However, bacterial resistance may occur in vitro and in vivo. 

Manufacturing processes for cephalosporin C and benzylpenicilhn are broadly similar. In common with mai other antibiotic fermentations, no specific precursor feed is necessary for cephalosporin C. There is sufficient acetyl group substrate for the terminal acetyltransferase reaction available fiom the organism s metabolic pool. 

Acquired resistance to the glycopeptides is transposon-mediated and has so far been largely confined to the enterococci. This has been a problem clinically because many of these strains have been resistant to all other antibiotics and were thus effectively untreatable. Fortunately, the enterococci are not particularly pathogenic and infections have been confined largely to seriously ill, long-term hospital patients. Two types of acquired glycopeptide resistance have been described (Woodford et al. 1995). The VanA phenotype is resistant to vancomycin and teicoplanin, whereas VanB is resistant... 

Another approaeh to the problem of providing an intravenous drug additive serviee is to add the drug to a small-volume (50-100 ml) infusion in a eollapsible plastie eontainer and store the preparation at -20°C in a freezer. The infusion ean be removed when required and thawed rapidly by microwave. Many antibiotics are stable for several months when stored in minibags at -20° C and are unaffected by the thawing process in a suitable microwave oven. Other antibiotics, e.g. ampieillin, are degraded when frozen. 

Skinner R, E Cundliffe, FJ Schmidt (1983) Site of action of a ribosomal RNA methylase responsible for resistance to erythromycin and other antibiotics. J Biol Chem 258 12702-12706. 

Although rum ammonia levels are not routinely measured, it is a useful indicator of Reye s syndrome and should be monitored in newborns at risk of developing hyperammonemia Ammonia is produced in many analytically useful enzyme reactions and the ammonium ISE has been used as the base sensor in several enzyme electrodes (see next section). In addition to valinomycin, other antibiotics such as the nonactin homalogs and gramicidins also behave as ionophores. The nonactin homolo were originally studied for their ability to selectively bind potassiiun ions It was then discovered that ammonium ions were preferred over potassium ions, and the selectivity coefficient Knh+ = 0.12 was reported. Since ammonia is present at fairly low levels in serum, this selectivity is not sufficient to to accurately measure NH4 in the presence of K. An extra measure of selectivity can be gained by using a gas permeable membrane to separate the ammonia gas from the sample matrix... 

The cornerstone of cholera treatment is fluid replacement. Without treatment, the case-fatality rate for severe cholera is approximately 50%. For cholera, rice-based ORT is better than glucose-based ORT because it reduces the number of stools.21 Patients with significant disease should receive a short antibiotic course, 1 to 3 days, to shorten the duration of illness and decrease the number of stools. Doxycycline 300 mg once daily is the drug of choice. Other antibiotics shown to be effective include erythromycin, azithromycin, trimethoprim-sulfamethoxazole, and ciprofloxacin.2 Antibiotic resistance has been documented in V cholerae since 1977.2 Antibiotic prophylaxis is not warranted. 

Baltz, R.H. (2006) Molecular engineering approaches to peptide, polyketide and other antibiotics. Nature Biotechnology, 24, 1533. 

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