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[Present problems and future trend of antifungals for deep seated mycosis. Azole antifungal agents].

Azole antifungal agents are the most common drugs for the treatment of deep seated mycosis throughout the world, because of their favorable anti-fungal spectrum, pharmacokinetics and safety. However there are some weak points in each drug or class, such as emerging resistance or interactions with other drugs. Many new derivatives are now under pre-clinical and clinical evaluation and among them, voriconazole and SCH56592 are showing satisfactory results in their early clinical studies. At the same time, however the ability of doctors to make an appropriate and logical choice for use of these drugs also essential.

Animals↗

The role of azole antifungal agents for systemic antifungal therapy.

Although amphotericin B remains the cornerstone of antifungal drug therapy, fluconazole and itraconazole have been found useful for long-term maintenance or prophylactic regimens. This article reviews characteristics of fluconazole and itraconazole and compares them with ketoconazole and amphotericin B.

Amphotericin B↗

Two new treatment options for infections due to drug-resistant gram-positive cocci.

Gram-positive cocci, including enterococci and Staphylococcus aureus, have become the leading cause of hospital-acquired infections, and their resistance to antibiotics is increasing. Two important new drugs-quinupristin/dalfopristin (Synercid) and linezolid (Zyvox)-were designed specifically to treat infections due to drug-resistant gram-positive cocci. But their use must be tempered by their cost, toxicity, and concerns about further development of resistant strains.

Acetamides↗

General principles of antimicrobial therapy.

Antimicrobial agents are appropriate treatment for acute, severe, persistent, or progressive infectious diseases. The efficacy of treatment depends on the accuracy of the diagnosis of infection and the appropriateness of the antimicrobial agent for the causative microorganism. In this symposium, the antimicrobial agents reviewed correspond with the bacterial, fungal, viral, mycobacterial, parasitic, chlamydial, and other microorganisms that cause disease in humans. Usually, the etiologic possibilities can be limited on the basis of the history and physical examination, laboratory tests, or results of treatment trials. Many of the same findings, however, can result from noninfectious, other inflammatory, or unknown mechanisms. Manifestations such as fever and organ dysfunction are nonspecific and often not caused by an infectious process. Even when infection is clinically apparent, the causative microorganism may not be identified, and empiric treatment with broad-spectrum agents is appropriate in many cases of serious disease.

Ambulatory Care↗

Bactericidal studies of penicillin-gentamicin combinations against group B streptococci.

The bactericidal activity of penicillin-aminoglycoside combinations was studied in 16 strains of Group B streptococci. Minimal inhibitory concentrations (MIC) against kanamycin or gentamicin were greater than 50 microgram/ml, whereas ampicillin or penicillin inhibitory concentrations were uniformly less than 0.1 microgram/ml. Although all strains had bactericidal concentrations (MBC) less than 0.1 microgram penicillin/ml, penicillin at a concentration equal to each strains respective MBC reduced inoculum colony forming units (CFU) 2 logs in only 6 of 16 strains in bactericidal kinetic studies. However, the addition of gentamicin in concentrations of 5.0 or 10.0 microgram/ml to penicillin markedly enhanced bactericidal activity in all strains tested. The addition of lower concentrations of gentamicin (1.0 microgram/ml) had minimal advantage over penicillin alone. No distinct advantage was noted for combinations including either ampicillin or kanamycin. The theoretical advantage of penicillin-aminoglycoside combinations in experimental conditions, suggests that the use of antibiotic combinations in clinical infections due to Group B streptococci, may result in a more rapid eradication of these organisms.

Ampicillin↗

The comparative beta-lactamase resistance and inhibitory activity of 1-oxa cephalosporin, cefoxitin and cefotaxime.

The beta-lactamase stability and inhibitory activity of 1-oxa cephalosporin, (6R,7R)-7-[[carboxy(4-hydroxyphenyl)acetyl]amino]-7-methoxy-3-[[(1-methyl-1H-tetrazol-5-yl)thio]methyl]-8-oxo-5-oxa-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid, was investigated and compared to that of cefoxitin and cefotaxime. There was no detectable beta-lactamase hydrolysis of 1-oxa cephalosporin, cefotaxime and cefoxitin when incubated with beta-lactamases of plasmid or chromosomal origin which were primarily cephalosporinases or enzymes which hydrolyzed both penicillins and cephalosporins. The beta-lactamase inhibitory activity of 1-oxa cephalosporin was comparable to that of cefoxitin and cefotaxime. At equal molar concentration of substrate and inhibitor, cefoxitin, cefotaxime and 1-oxa cephalosporin effectively inhibited cephalosporinase hydrolysis of cephaloridine. Cefoxitin and cefotaxime were more effective inhibitors than the 1-oxa cephalosporin against a Providencia enzyme, whereas cefotaxime and 1-oxa cephalosporin were more effective inhibitors of a Citrobacter cephalosporinase.

Bacteria↗

Asparenomycins A, B and C, new carbapenem antibiotics. IV. Antibacterial activity.

Asparenomycins (ASM) A, B and C, new members of the carbapenem family of antibiotics, are broad spectrum antibiotics with activity against Gram-positive and Gram-negative bacteria. ASM A was bactericidal to both aerobic and anaerobic bacteria, although morphological alterations of ASM A exposed cells differed significantly between Escherichia coli and Bacteroides fragilis; with the former ovoidal forms were produced while with the latter elongated forms were seen. Synergistic activities were observed with a combination of ASM A and ampicillin (ABPC) against various ABPC-resistant bacteria presumably as a result of the inhibition by ASM A of beta-lactamases. ASM A showed relatively weak therapeutic activity against E. coli infected mice, because of instability in body fluids, a common property of the carbapenem family of antibiotics.

Animals↗

5-N-acetylardeemin, a novel heterocyclic compound which reverses multiple drug resistance in tumor cells. I. Taxonomy and fermentation of the producing organism and biological activity.

The ardeemins are a new family of secondary metabolites produced by submerged fermentation of a fungus which was isolated from a soil sample collected in Brazil. Based on taxonomic studies, the producing culture was identified as Aspergillus fischeri var. brasiliensis strain AB 1826M-35. 5-N-Acetylardeemin potentiated the cytotoxicity of the anticancer agent vinblastine in multidrug resistant human tumor cells.

Antibiotics, Antineoplastic↗

Drugs five years later: acyclovir.

In the 5 years since its release for clinical use, acyclovir (9-[2-hydroxyethoxymethyl]guanine) has proved to be a safe and effective agent for therapy of herpes simplex and varicella-zoster infections. The drug's availability in topical, oral, and intravenous preparations has allowed its use in a range of clinical situations. Acyclovir must be phosphorylated by viral thymidine kinase in infected cells, where it then acts to inhibit viral DNA replication specifically. Epstein-Barr virus and human cytomegalovirus infections do not seem to respond to acyclovir therapy, although in-vitro effects on these viruses may be seen. Acyclovir is well absorbed and distributed, with cerebrospinal fluid levels 50% that of plasma. Clearance is almost entirely by the renal route, with a half-life of 20 hours in the anuric patient. Acyclovir has an excellent safety profile, its major adverse effect being transient serum creatinine elevations during high-dose intravenous use. Major uses include treatment of primary and recurrent genital herpes and herpes encephalitis and prophyllaxis and therapy of mucocutaneous herpes and varicella-zoster infections in immunocompromised patients. Resistance to acyclovir in herpes simplex virus is rarely encountered and does not seem to be due to long-term chronic suppressive therapy.

Acyclovir↗

Rifampin.

In 1971, rifampin was approved for treatment of pulmonary tuberculosis and asymptomatic carriers of Neisseria meningitidis. At present, the approved indications remain the same. However, rifampin in conjunction with at least one other antituberculous drug may be of great value in therapy of extrapulmonary tuberculosis and infections due to other susceptible mycobacteria. In addition, results of clinical trials in leprosy have been highly encouraging. Rifampin appears to induce light chain proteinuria in a majority of patients and has been implicated in suppression of both humoral and cell-mediated immune responses. However, these effects appear to have been of little consequence to treated patients. A variety of possibly immunologically mediated reactions to rifampin has been closely associated with irregular administration of the drug. These reactions and hepatic toxcity may be preventable in many patients. Rifampin or one of its congeners, alone or in combination with other antibiotics, may prove useful in treatment of various infectious, and possibly malignant, diseases.

Animals↗

Suppression of replication of multidrug-resistant HIV type 1 variants by combinations of thymidylate synthase inhibitors with zidovudine or stavudine.

The replication of recombinant multidrug-resistant HIV-1 clones modeled on clinically derived resistant HIV-1 strains from patients receiving long-term combination therapy with zidovudine (AZT) plus 2',3'-dideoxycytidine was found to regain sensitivity to AZT and stavudine (D4T) as a consequence of a pharmacologically induced decrease in de novo dTMP synthesis. The host-cell system used was phytohemagglutinin-stimulated peripheral blood mononuclear cells; dTMP and dTTP depletion were induced by single exposures to a low level of the thymidylate synthase inhibitor 5-fluorouracil (5-FU) or its deoxynucleoside, 2'-deoxy-5-fluorouridine. The host-cell response to the latter was biphasic: a very rapid decrease in the rate of de novo dTMP formation and, consequently, in intracellular dTTP pools, followed by slower recovery in both indices over 3 to 24 h. With the additional presence of AZT or D4T, however, replication of the multidrug-resistant HIV-1 strains remained inhibited, indicating dependence of HIV DNA chain termination by AZT-5'-monophosphate or 2',3'-didehydro-2', 3'-dideoxythymidine-5'-monophosphate in these resistant strains on simultaneous inhibition of host-cell de novo synthesis of thymidine nucleotides. No effect on viability of control (uninfected) phytohemagglutinin-stimulated/peripheral blood mononuclear cells was noted on 6-day exposures to 5-FU or 2'-deoxy-5-fluorouridine alone or in combination with AZT or D4T, even at drug levels severalfold higher than those used in the viral inhibition studies. These studies may provide useful information for the potential clinical use of AZT/5-FU or D4T/5-FU combinations for the prevention or reversal of multidrug resistance associated with long-term dideoxynucleoside combination therapy.

Anti-HIV Agents↗

[The need for new antituberculosis agents in Japan].

We discussed the need of new antituberculosis agents in Japan concerning drug adverse reactions in particular as well as drug interactions and drug resistance. We reviewed medical charts of hospitalized patients receiving standard antituberculosis chemotherapy (INH + RFP + EB/SM +/- PZA), and analyzed all symptoms, signs and abnormal laboratory data presumably caused by the chemotherapy. About 48% of 228 cases analyzed had at least 1 episode of adverse reactions: 77 episodes of hepatotoxicity, 15 episodes of ototoxicity, 14 episodes of eruption, 14 episodes of ocular toxicity and so on. About 23% cases treated with RFP, 20% cases with SM, 12% cases with INH and 7.7% cases with EB had at least 1 episode of adverse reactions due to the corresponding agent. In 59 cases, at least one agent was stopped to administer because of adverse reactions. Finally, standard chemotherapy could not be completed in 23% of all cases, and in stead, the other agents, mainly new quinolones, were administered. RFP induces cytochrome P450 3A in the liver to decrease the activities of many drugs, such as cyclosporin A, tacrolimus, protease inhibitor, itraconazole, and clarithromycin. In some clinical settings, RFP cannot be administered in combination with such drugs. In conclusions, new antituberculosis agents that have strong activities with less adverse reactions and drug interactions are needed in Japan, even without considering drug resistance.

Aged↗

[Antibiotic policy].

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Anti-Bacterial Agents↗

[Trovafloxacin].

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Animals↗