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PubMed1992

Proteolytic cleavage by neutrophil elastase converts inactive storage proforms to antibacterial bactenecins.

Bac5 and Bac7, antibiotics of the bactenecin (proline/arginine-rich peptide) family, are stored as proforms in the large granules of bovine neutrophils [Zanetti, M., Litteri, L., Gennaro, R., Horstmann, H. and Romeo, D. (1990) J. Cell Biol. 111, 1363-1371]. These proforms have been purified to homogeneity from granule extracts by immunoaffinity and reverse-phase chromatography. While mature bactenecins efficiently kill Escherichia coli, Klebsiella pneumoniae and Salmonella typhimurium with minimal inhibitory concentrations of 6-12 micrograms/ml, proBac5 and proBac7 do not affect the growth of the same microorganisms, even at 500 micrograms/ml. Previous investigations have suggested that the conversion of probactenecins into mature antimicrobial peptides is catalyzed by a neutral serine protease stored in the azurophil granules. Purified proBac5 and proBac7 were thus treated with elastase, cathepsin G or proteinase 3, which constitute the pool of neutral serine proteases of the azurophils, and the reaction products were identified by Western blot analysis, mass spectrometry, and N-terminal sequence analysis. Of the three proteases, only elastase is able to catalyze the stepwise cleavage of probactenecins into the corresponding mature peptides, which have the same mass, N-terminal sequence and antibiotic activity of authentic Bac5 and Bac7. These results point to the importance of cooperation between azurophils and large granules in mounting a defense reaction.

Animals↗
PubMed2003

Chemical and biological interactions during nitrate and goethite reduction by Shewanella putrefaciens 200.

Although previous research has demonstrated that NO(3)(-) inhibits microbial Fe(III) reduction in laboratory cultures and natural sediments, the mechanisms of this inhibition have not been fully studied in an environmentally relevant medium that utilizes solid-phase, iron oxide minerals as a Fe(III) source. To study the dynamics of Fe and NO(3)(-) biogeochemistry when ferric (hydr)oxides are used as the Fe(III) source, Shewanella putrefaciens 200 was incubated under anoxic conditions in a low-ionic-strength, artificial groundwater medium with various amounts of NO(3)(-) and synthetic, high-surface-area goethite. Results showed that the presence of NO(3)(-) inhibited microbial goethite reduction more severely than it inhibited microbial reduction of the aqueous or microcrystalline sources of Fe(III) used in other studies. More interestingly, the presence of goethite also resulted in a twofold decrease in the rate of NO(3)(-) reduction, a 10-fold decrease in the rate of NO(2)(-) reduction, and a 20-fold increase in the amounts of N(2)O produced. Nitrogen stable isotope experiments that utilized delta(15)N values of N(2)O to distinguish between chemical and biological reduction of NO(2)(-) revealed that the N(2)O produced during NO(2)(-) or NO(3)(-) reduction in the presence of goethite was primarily of abiotic origin. These results indicate that concomitant microbial Fe(III) and NO(3)(-) reduction produces NO(2)(-) and Fe(II), which then abiotically react to reduce NO(2)(-) to N(2)O with the subsequent oxidation of Fe(II) to Fe(III).

Culture Media↗
PubMed2000

The structural biology of molecular recognition by vancomycin.

Vancomycin is the archetype among naturally occurring compounds known as glycopeptide antibiotics. Because it is a vital therapeutic agent used world-wide for the treatment of infections with gram-positive bacteria, emerging bacterial resistance to vancomycin is a major public health threat. Recent investigations into the mechanisms of action of glycopeptide antibiotics are driven by a need to understand their detailed mechanism of action so that new agents can be developed to overcome resistance. These investigations have revealed that glycopeptide antibiotics exhibit a rich array of complex cooperative phenomena when they bind target ligands, making them valuable model systems for the study of molecular recognition.

Anti-Bacterial Agents↗
PubMed2003

Treatment of acne with isotretinoin: recommendations based on Australian experience.

Oral isotretinoin revolutionized acne treatment when it was introduced in 1982 in the USA. However, its use was restricted to patients with severe nodulocystic acne. Today its use worldwide has expanded to treat also patients with less severe but scarring acne who are responding unsatisfactorily to conventional therapies. These recommendations assess the potential for use of oral isotretinoin as a safe and effective treatment for severe nodulocystic acne unresponsive to conventional therapy, and acne of any severity that causes scarring or is associated with psychological distress.

Acne Vulgaris↗
PubMed1987

Institution-specific versus published in vitro antimicrobial susceptibility data in making formulary decisions.

The results of susceptibility testing of 549 isolates of gram-negative organisms to 17 antimicrobial agents were compared with published reports of the sensitivity of those organisms to those agents. All gram-negative bacilli isolated from cultures obtained from hospitalized patients during a three-month period were preserved for antimicrobial sensitivity testing. Standard Kirby-Bauer disk diffusion susceptibility tests were performed using 17 broad-spectrum antimicrobial agents that either were included in the hospital formulary or were being considered for inclusion. Organisms were recorded as being sensitive or resistant to each drug, and the results were compared with the published results of in vitro sensitivity studies. When the results of actual antimicrobial sensitivity testing varied from published results, the discordant results were assigned a ranking of 1 to 4 based on the percentage difference. In 34 of 77 drug-organism pairs tested, the results of susceptibility testing differed by more than 10% cumulative susceptibility from published values; 26 of these represented instances in which the results of actual testing were at least 10% less than published values. For seven of the antimicrobial agents that were being considered for inclusion in the hospital formulary, results indicating unexpectedly suboptimal activity against institutional pathogens were a determinant in eliminating the agents from further consideration. In vitro testing of antimicrobial susceptibility of local pathogens can be a better method of predicting the susceptibility of such pathogens to new antimicrobial agents than relying on published susceptibility data. Pharmacy and therapeutics committees should consider testing prevalent institutional pathogens for susceptibility to all antimicrobial agents that are proposed additions to the formulary.

Aminoglycosides↗
PubMed1977

[Hospital infections from a bacteriological viewpoint].

In spite of the successful treatment of bacteriological infections combined with progress in hospital hygiene there remain still problems of infective hospitalism in certain sections of the hospital. Generally, the causative bacteria are nosoparasites not being dangerous to human beings in good condition. From this point of view Pseudomonas aeruginosa and Serratia marcescens are the most important species. A successful challenge against infective hospitalism is only possible under the supervision of the bacteriologist. It is his task to isolate and differentiate the bacteria and to carry out the sensitivity tests against antibiotics. Besides this, he has to treat epidemiological and hygienic problems. Special kinds of methods sometimes have to be used to find out the sources and the routes of spreading of the infections in a hospital e.g. bacteriophage typing, bacteriocin typing and analysis of the antigenic structure. Likewise, the transmission of bacteria by air has to be studied and continuous controlling measures and monitoring are required. The bacteriologist is also responsible for preparing hygiene instructions. There always has to exist a good cooperation between the bacteriologist, the clinical doctors, the nurses and the technical staff. The whole problem can only be handled by special teams.

Antigens, Bacterial↗
PubMed2003

Use of audit tools to evaluate the efficacy of cleaning systems in hospitals.

BACKGROUND: Recent publicity has highlighted both the inadequacies of hospital cleaning and high levels of methicillin-resistant Staphylococcus aureus infections in UK hospitals. "Standards for Environmental Cleanliness" (SEC) was a checklist developed in April 1999 by the Infection Control Nurses Association and the Association of Domestic Managers to evaluate cleaning services regardless of who is the provider. More recently, the National Health Service plan (July 2000) was an attempt to generate a rapid improvement in the cleanliness and tidiness of hospitals via a National Health Service patient environment audit (PEA). On the basis of models used in the food industry to manage cleaning practices cost-effectively, a risk-based audit checklist incorporating rapid hygiene monitoring was developed to assess the adequacy of cleaning programs and standards in hospitals. This checklist (Audit for Cleaning Efficacy, or ACE) as well as the SEC and PEA approaches were applied at 4 hospitals, and environmental microbial surface counts were compared. SEC and PEA rely on visual assessment, whereas the ACE approach is more comprehensive and included more specific questions relating to the management and monitoring of cleaning as well as standards on the basis of rapid hygiene monitoring. METHODS: Two wards in each of the 4 hospitals were visited on 3 separate occasions immediately after cleaning was completed. Visual assessment, adenosine triphosphate bioluminescence, and microbiologic sampling of selected environmental sites were performed to evaluate the effectiveness of cleaning. The 3 audits were completed during the final hospital visit. RESULTS: Visual assessment indicated that 90% of sites were satisfactory, whereas adenosine triphosphate bioluminescence showed that 100% and microbiologic sampling showed that 90% of sites did not meet benchmark values. There was no significant difference between the SEC and PEA audits (P =.311), which used visual assessment, and the results suggest that they both are similar in passing surfaces that have microbiologic benchmark values that are too high. However, the ACE audit showed a significant difference (P = <.001) in results compared with the SEC and the PEA audits and did not pass surfaces with microbiologic benchmark values that were too high. The ACE audit, which incorporates rapid hygiene testing, showed a much stronger association with the microbial counts; this was not apparent with the SEC and the PEA audits. CONCLUSION: The data suggest that visual assessment is a poor indicator of cleaning efficacy and that the ACE audit gives a better assessment of cleaning programs compared with the other 2 audit methods in relation to microbial surface counts. It is recommended that hospital cleaning regimes be designed to ensure that surfaces are cleaned adequately and that efficacy is assessed with use of internal auditing and rapid hygiene testing.

Adenosine Triphosphate↗
PubMed1983

[Problems related to the deposition of microorganisms in the patent procedure].

Some practical aspects concerning deposition of microbial strains in connection with patenting are discussed. In particular, situations requiring deposition of individual strains, mixed cultures or associants are analysed. Problems of patent legislation pertinent to deposition of microorganisms are discussed.

International Cooperation↗
PubMed2004

ComBase: a common database on microbial responses to food environments.

The advancement of predictive microbiology relies on available data that describe the behavior of microorganisms in different environmental matrices. For such information to be useful to the predictive microbiology research community, data must be organized in a manner that permits efficient access and data retrieval. Here, we describe a database protocol that encompasses observations of bacterial responses to food environments, resulting in a database (ComBase) for predictive microbiology purposes. The data included in ComBase were obtained from cooperating research institutes and from the literature and are publicly available via the Internet.

Bacteria↗
PubMed2000

Failure of treatment with cephalexin for Lyme disease.

CONTEXT: Lyme disease typically presents with a skin lesion called erythema migrans (EM), which though often distinctive in appearance may be confused with cellulitis. The first-generation cephalosporin, cephalexin monohydrate, is effective for treating bacterial cellulitis but has not been recommended or studied for treating Lyme disease because of poor in vitro activity. OBJECTIVE: To describe the outcome of patients with EM who were treated with cephalexin. PATIENTS AND METHODS: Patients presenting with EM to the Lyme Disease Diagnostic Center in Westchester, NY (May 1992-September 1997). A 2-mm punch biopsy specimen of the leading edge of the EM lesion and/or blood was cultured for Borrelia burgdorferi. RESULTS: Eleven (2.8%) of 393 study patients had been initially treated with cephalexin prior to our evaluation; 9 (82%) were originally diagnosed with cellulitis. Cephalexin was administered for 8.6 days (range, 2-21 days) prior to presentation. All 11 patients had clinical evidence of disease progression, including 8 whose rash enlarged, 2 who developed seventh-nerve palsy (1 with new EM lesions), and 1 who developed new EM lesions. Borrelia burgdorferi grew in cultures from 5 patients despite a mean of 9.8 days of treatment with cephalexin (range, 5-21 days). CONCLUSION: Cephalexin should not be used to treat early Lyme disease and should be prescribed with caution during the summer months for patients believed to have cellulitis in locations where Lyme disease is endemic.

Adult↗
PubMed1980

Phenytoin therapy of recessive dystrophic epidermolysis bullosa. Clinical trial and proposed mechanism of action on collagenase.

We administered phenytoin (diphenylhydantoin) by mouth to 17 unselected patients to assess its ability to reduce blistering in recessive dystrophic epidermolysis bullosa (RDEB). Therapeutic response was correlated with blood levels of the drug. Although there was a decrease in blistering of 53 +/- 6 per cent (mean +/- S.E.) among all patients at levels of more than 8 microgram of phenytoin per milliliter, the response was variable, with 12 of 17 patients having a decrease in blistering of more than 40 per cent. Since increased collagenase in human skin has been implicated in the pathogenesis of blistering in RDEB, we examined the effect of phenytoin on this enzyme. Although the drug did not inhibit collagenase activity directly, its addition to human-skin explant and fibroblast cultures produced a 50 to 60 per cent decrease in collagenase activity and immunoreactive protein concentrations. These in vitro studies suggest that phenytoin inhibits synthesis or secretion of collagenase of both, and that the favorable clinical response can be explained by this inhibition.

Administration, Oral↗
PubMed1997

One week triple therapy for Helicobacter pylori: a multicentre comparative study. Lansoprazole Helicobacter Study Group.

BACKGROUND: Eradication of Helicobacter pylori cures and prevents the relapse of duodenal ulceration and also results in histological resolution of chronic active gastritis. AIM: To compare four treatment regimens lasting seven days of a proton pump inhibitor and two antibiotics in the eradication of H pylori. PATIENTS: Men or women with H pylori positive duodenal ulceration or gastritis, or both. METHODS: A single blind, prospectively randomised, parallel group, comparative, multicentre study. After a positive CLO test, patients underwent histology, H pylori culture, and a 13C urea breath test to confirm H pylori status. Treatment with one of four regimens: LAC, LAM, LCM, or OAM, where L is 30 mg of lansoprazole twice daily, A is 1 g of amoxycillin twice daily, M is 400 mg of metronidazole twice daily, C is 250 mg of clarithromycin twice daily, and O is 20 mg of omeprazole twice daily, was assigned randomly. A follow up breath test was done at least 28 days after completing treatment. RESULTS: H pylori eradication (intention to treat) was 104/121 (86.0%) with LAC, 87/131 (66.4%) with LAM, 103/118 (87.3%) with LCM, and 94/126 (74.6%) with OAM. There was a significant difference (p < 0.001) in the proportion of patients in whom eradication was successful between LAC and LCM when compared with LAM, but no significant difference (p = 0.15) between LAM and OAM. Metronidazole resistance before treatment was identified as a significant prognostic factor with regard to eradication of H pylori. The regimens which contained metronidazole were significantly less effective than those without metronidazole in the presence of pretreatment resistant H pylori. There was no difference among the treatment groups with regard to the incidence and severity of adverse events reported. CONCLUSIONS: All four treatment regimens were safe and effective in eradicating H pylori in the patient population studied. LAC was the most efficacious treatment in patients with pretreatment metronidazole resistant H pylori, and was significantly better than LAM and OAM in this group of patients.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMedDate not supplied

Activity of twenty-one antimicrobial agents including l-ofloxacin against quinolone-sensitive and -resistant, and methicillin-sensitive and -resistant Staphylococcus aureus.

There is a need to identify alternative agents to vancomycin for the treatment of infections with methicillin-resistant Staphylococcus aureus (MRSA). One candidate is the l isomer of ofloxacin (DR-3355). We tested 520 frozen MRSA isolates, 248 fresh MRSA isolates, and 375 fresh methicillin-susceptible S. aureus (MSSA) isolates from Minnesota, and 600 clinical isolates of S. aureus (150 MRSA and 450 MSSA) from Illinois. Over 90% of the MRSA strains were resistant to 32 micrograms/ml of oxacillin. Of the 520 frozen MRSA, 24% were susceptible to < or = 2 micrograms/ml ofloxacin, and an additional 74% were susceptible to ofloxacin between 8 and 16 micrograms/ml. More than 98% of all strains were susceptible to < or = 16 micrograms/ml ofloxacin or l-ofloxacin. All the quinolones had a bimodal distribution of in vitro activity, but for only ofloxacin and l-ofloxacin was activity confined to a very narrow range.

Anti-Bacterial Agents↗
PubMedDate not supplied

Characterization of cysteamine as a potential contraceptive anti-HIV agent.

Cysteamine (beta-mercaptoethylamine, or MEA) is a thiol-reducing agent and has anti-HIV activity. Because of these properties, cysteamine was evaluated as a vaginal contraceptive and tested for its effects on sperm function and on other sexually transmitted microbes. Cysteamine was contraceptive in the rabbit. Conception was inhibited completely when sperm were pretreated with 500 microg/ml cysteamine and was inhibited by more than 60% when 7.5 mg cysteamine was applied vaginally as a suspension in 50% K-Y Jelly. Cysteamine had multiple effects on spermatozoa. Both acrosin (EC 3.4.21.10) and hyaluronidase (EC 3.2.1.35) were reversibly inhibited by cysteamine. Calculated IC50 values were 370 microg/ml and 150 microg/ml for acrosin and hyaluronidase, respectively. Cysteamine behaved as a poor spermicide when activity was measured by the 30-second Sander-Cramer test. However, sperm motility was inhibited completely when cysteamine was preincubated for 10 minutes prior to motility evaluation, at concentrations as low as 50 microg/ml. The calcium ionophore A23187-induced human acrosome reaction was inhibited by cysteamine (IC50 = 0.5 microg/ml). Neither herpes simplex virus nor Neisseria gonorrhoeae was affected by cysteamine at concentrations as high as 500 microg/ml and 100 microg/ml, respectively. Cysteamine appears to have no effect on normal vaginal flora (i.e., lactobacillus). These results, together with published data, strongly support the further development of cysteamine as a topical contraceptive anti-HIV agent.

Acrosin↗
PubMed1976

Regulation of ion permeabilities of isolated rat liver cells by external calcium concentration and temperature.

Regulation of ion transport through the plasma membrane was studied on single cell suspensions of hepatocytes, obtained after perfusion of rat liver with collagenase/hyaluronidase solution. Steady-state intracellular K and Na contents were shown to be markedly dependent on external Ca concentration and temperature, the sum of both ion concentrations remaining nearly constant. In contrast, steady-state intracellular chloride content was found to be independent of external Ca concentration, but dependent on temperature. Using the constant field relations, the passive permeabilities PK and PCl for potassium and chloride, respectively, were derived from the experimental data. At temperatures at and above 37 degrees C, with increasing external Ca concentration, PK, exhibits a sharp decrease at about 10(-4)M. In contrast, PCl at 37 degrees C was found to be independent of Ca concentration within experimental error. Earth alkali ions other than Ca, show marked but different effects on PK if compared at equal concentrations. Preincubation of the cells with cholesterol leads to a broadening of the dependence of PK on external Ca concentration. The above results, as well as those on the dependence of PK on external Ca concentration obtained by other authors, could be quantitatively described by a theoretical model of the plasma membrane proposed earlier. This model postulates regulatory binding sites, which cooperatively undergo a cation exchange of divalent cations by K+ ions from the external medium if the cation composition of the latter is altered.

Animals↗
PubMed2002

Atopic dermatitis: review of immunopathogenesis and advances in immunosuppressive therapy.

This paper reviews the theories of the pathogenesis of atopic dermatitis (AD), with a particular emphasis on its immunopathogenesis. The contribution of predisposing factors, immunopathogenic factors and provoking factors in the pathogenesis of AD are considered. Predisposing factors explored in this article include genetics and the disturbance of skin function. Immunopathogenic factors reviewed include T cell dysfunction, biphasic cytokine expression and the role of immunoglobulin E. Provoking factors considered include microbial factors, psychosomatic interactions, contact allergens and irritants, inhalant allergens, food and climate. Immunosuppressive treatments reviewed include cyclosporin, azathioprine, methotrexate, tacrolimus, interferon-gamma, phosphodiesterase inhibitors and pimecrolimus (SDZ ASM 981).

Dermatitis, Atopic↗