Increased microbicidal activity of green tea (Camellia sinensis) in combination with butylated hydroxyanisole.

We have demonstrated that green tea (Camellia sinensis) shows increased antimicrobial activity against bacteria and fungi when used in combination with butylated hydroxyanisole (BHA). Glycolic extract taken from green tea showed only limited activity against Streptococcus mutans and no activity against Candida albicans and certain strains of Escherichia coli. BHA, at non inhibitory concentrations, increased the microbicidal activity of green tea against 10(10) S. mutans (p<0.01), non-susceptible E. coli (p<0.01) and C. albicans (p<0.01). Green tea in combination with BHA reduced the hydrophobicity of S. mutans (p<0.01) and greatly inhibited (p<0.001) the formation of hyphae in C. albicans. The increased antimicrobial activity of green tea is related to an impairment of the barrier function in microorganisms and a depletion of thiol groups. The increased activity of green tea as an oral antimicrobial product is discussed.

Tetracycline in combination with sodium dioctylsulfosuccinate show increased antimicrobial activity in resistant microorganisms.

We present evidence that sodium dioctylsulfosuccinate, at non inhibitory concentrations (1000 mg/L), is able to increase the antimicrobial activity of tetracycline in non susceptible bacterial and fungal strains. In culture inhibition tests, pretreatment with sodium dioctylsulfosuccinate caused a 52-fold decrease in the geometric mean MIC to tetracycline in 10 Candida albicans strains (p<0.01), a 165-fold decrease in the geometric mean MIC to tetracycline in 10 E. coli strains (p<0.001) and a significant decrease in the mean MIC of 3 strains of Candida krusei and Candida glabrata. In microbicidal tests, tetracycline in association with sodium dioctylsulfosuccinate killed 10(4) cfu tetracycline-resistant Candida albicans in 15 min and 10(4) CFU resistant E. coli in 3 min (p<0.001). Furthermore, in the N-acetyl-D-glucosamine test to calculate the number of hyphal cells, a combination of tetracycline (50 mg/L) (non inhibitory concentrations) plus sodium dioctylsulfosuccinate (25 mg/L) caused a 50-fold increase in the inhibition of hyphal cells in C. albicans (p<0.001); C. albicans cells treated with tetracycline plus sodium dioctylsolfosuccinate annulled the cell surface hydrophobicity (p<0.001). This increase in antimicrobial activity may be attributed to impairment and alteration of the membrane barrier within the microorganisms and a depletion of the thiol groups (p<0.001) critical to their efficiency.

Enhanced contact activity of fluconazole in association with antioxidants against fluconazole-resistant organisms.

Fluconazole alone does not demonstrate any contact activity against resistant organisms. Phenolic antioxidants, such as butylated hydroxyanisole, appear to promote fluconazole activity resulting in the killing of 10(4) cfu/mL of 11 resistant Candida albicans strains within 3-15 min and of 10(4) cfu/mL of 10 resistant Escherichia coli strains within 6-15 min. Fluconazole activity was increased by the addition of ethyl alcohol (20%). Antioxidants appear to promote fluconazole activity by increasing cell membrane permeability. This combination has potential advantages in the administration of topical fluconazole.

Contact imidazole activity against resistant bacteria and fungi.

The activities of miconazole and miconazole sulphosalicylate were evaluated by a contact test using strains of Enterococcus faecalis and Escherichia coli and Candida spp selected for their resistance. The results showed that killing of the organisms occurred within a few minutes. Imidazole activity required a medium of low electrical conductivity and a pH of 5.6. Greater sensitivity could be obtained with pretreatment of the microbial suspensions with sodium dioctylsulphosuccinate. Microorganisms tested in culture media with low electrical conductivity and at pH 5.6 showed enhanced sensitivity to azoles with MIC values about 20-30 times lower than those obtained using control media. Practical implications of the use of topical drugs are discussed.

In vitro activity of propyl gallate-azole drug combination against fluconazole- and itraconazole-resistant Candida albicans strains.

AIMS: The influence of an antioxidant, propyl gallate (PG), on the in vitro antifungal activity of itraconazole and fluconazole, was investigated to determine whether PG could increase the antifungal activity and reduce strain resistance. METHODS AND RESULTS: Susceptibility tests were performed against azole-resistant isolates of Candida albicans by the microbroth dilution method in the presence of PG at 400 microg ml-1. PG-triazole combination brought about a marked reduction of inhibitory azole concentration. In particular, the MIC90 for itraconazole and fluconazole dropped from 1 microg ml-1 to 0.125 microg ml-1 and from > 64 microg ml-1-8 microg ml-1, respectively. CONCLUSION: It is likely that more than one mechanism is involved in the above synergistic interaction, including effects of PG on ATP synthesis, thus reducing the ABC transporters activity, or an effect on the target of azole, i.e. the P-450 cytochrome. SIGNIFICANCE AND IMPACT OF THE STUDY: The PG-triazole combination may have a role in future topical antifungal strategies but other studies are warranted.

Anticandidal activity of SPA-S-843, a new polyenic drug.

The activity of a new, soluble and stable polyene (SPA-S-843) against Candida albicans was assessed by contact and culture tests and by inhibition of germ-tube formation. The drug demonstrated a higher contact activity and lower MICs than amphotericin B. This antimicrobial activity was more evident under acid pH and low ionic strength. In addition, the ability of SPA-S-843 to inhibit Candida sp. conversion from yeast to mycelial form was evident at low drug concentrations (0.25-0.62 mg/L).

Antifungal activity of ketoconazole and other azoles against Malassezia furfur in vitro and in vivo.

The in vitro activity of several antifungal agents (ketoconazole, miconazole, econazole, fenticonazole, itraconazole, fluconazole) in routine clinical use against Malassezia furfur infections has been studied with freshly isolated strains of M. furfur from pityriasis versicolor lesions. The results indicate that the drugs tested exert a good activity, and both ketoconazole and itraconazole appear very active (0.8 mg/l respectively). Hair samples from the beards of volunteer patients affected by pityriasis versicolor but otherwise healthy were examined to determine ketoconazole levels during oral therapy (one or two 200 mg tablets daily). It was shown that the drug progressively accumulates in the beard, reaching levels proportional to the dose administered, although blood levels did not increase in parallel. The study of drug concentration profile has evidenced a long ketoconazole persistence in the beard at therapeutic levels. In conclusion, the possibility of reaching high and lasting ketoconazole levels in the keratin layer of the epidermis indicates that systemic ketoconazole therapy could be useful for eradication of M. furfur in patients affected by pityriasis versicolor.

Overcoming Streptococcus agalactiae in vitro resistance to imidazoles.

The increased diffusion of Streptococcus agalactiae in the urinary tract and vagina has affected the strain's resistance to antimicrobial agents, so we decided to study the possibility of overcoming its resistance to imidazoles. Our data suggest that overcoming S. agalactiae resistance to imidazoles in contact and growth culture tests depends partly on the electrical conductivity of the culture medium. Although imidazole contact activity and culture activity have different targets in cell structures, we have demonstrated that imidazole resistance in S. agalactiae cells in both types of tests can be affected by the same conditions regulating membrane permeability.

In vivo and in vitro antifungal activity of the polyene derivative SPA-S-753 against encapsulated form of Cryptococcus neoformans.

The in vitro and in vivo activity of SPA-S-753 (N-dimethylaminoacetyl-partricin A 2-dimethylaminoethylamide diaspartate), a new water soluble polyene, was compared with amphotericin B against Cryptococcus neoformans in encapsulated (K) and nonencapsulated (N) morphological forms. In vitro tests against 17 isolates of C. neoformans (in K or N form) showed that SPA-S-753 activity is about ten times higher than that of amphotericin B. In direct contact tests the SPA-S-753 cytocidal action was significantly higher than that of amphotericin B; the K cells are, however, less sensitive to the cytocidal action exerted by the two polyenes even when using concentrations 4-fold higher than those used against the N cells and they present a smaller potassium ion release. The cytocidal activity of the two polyenes is favoured by a low electrolyte concentration and an acid pH. SPA-S-753 microbicidal activity by contact in vivo, in mice infected with C. neoformans N cells by i.p. route, is more powerful than that of amphotericin B. In protection tests in mice infected with 10 LD50 of C. neoformans K cells, SPA-S-753 action is again more powerful, but not to a significant degree, than that of amphotericin B. In conclusion, both substances showed a reduced in vitro and in vivo activity against C. neoformans in the K morphological form. Nevertheless our results demonstrate that SPA-S-753 exerts an antifungal overall activity that is more effective than that of amphotericin B under similar experimental conditions.

Utilization of electrochemical silver ions as preservative agent in cosmetic dispersions.

The use of anodic silver ions as preserving agents in cosmetics was tested by a challenge test in a set of cosmetic dispersions with the addition of known preservative inhibitors or micro-organism growth-promoters such as humectants, hydrosoluble collagen and vegetable extracts. Silver's microbicidal efficacy, compared to that of imidazolidinyl urea or methyl p-hydroxybenzoate, showed a more efficient activity especially in the presence of proteinaceous material. This agent may represent a good and safe protection for finished products both in manufacture and during use.

Emergency medical services in mass gatherings: the experience of the Formula 1 Grand Prix 'San Marino' in Imola.

Mass gatherings are special situations for which mass medical care must be preplanned. Acute emergencies occur at public gatherings and medical coverage on site has proven benefit. Responsibility of general plan, management of specific problems, transport planning, communications system, guidelines and protocols, special situations management, ancillary supports, sources of extra help for unforeseen needs are the most important items to consider. In mass gatherings the whole emergency medical service (EMS) planning and management has to depend on the emergency department direction, with its authority on all aspects of patient care in the EMS system. This report concerns the planning of EMS and of medical care in a situation at risk for mass casualties at the Formula I Grand Prix-Championship Racing 'San Marino' of Imola.

Study of interaction effects of polyacrylic acid polymers (carbopol 940) on antimicrobial activity of methyl parahydroxybenzoate against some gram-negative, gram-positive bacteria and yeast.

Cosmetic or pharmaceutical formulations containing hydrophilic polymers of natural or synthetic origin, may be more exposed to successful microbial contamination because of a polymer-preservative interaction. The experimental data reported in this paper relate to the possible interference of Carbopol 940 with methyl parahydroxybenzoate. Results show that this hydrophilic polymer, widely employed in many formulations, exerts, on the contrary, an interesting synergism on microbicidal activity of the preserving agent against E. coli and P. Aeruginosa. A reduction in microbicidal activity against S. aureus and C. albicans is observed for a polymer concentration higher than that needed for anti-Gram-negative synergy.

Synthesis and microbiological evaluations of (N-heteroaryl) arylmethanamines and their Schiff bases.

The synthesis as well as the antimicrobial and antiviral activities of new (N-heteroaryl)arylmethanamines and their Schiff bases are reported. None of the tested compounds shown activity against Herpes simplex virus type 2 and against Gram positive and Gram negative bacteria. Weak or moderate activity on poliovirus Sabin type 1, on reverse transcriptase and against Cryptococcus neoformans was shown by some of the tested compounds. Viceversa several synthesized compounds exhibited a moderate or good activity against strains of Candida albicans, while only some of the tested compounds were found moderately active against strains of Candida sp. Instead numerous new compounds 3 or 4 were active as control against isolates of plant pathogenic fungi. The obtained results are discussed on the basis of structure-activity relationships.

Overcoming imidazole resistance in Escherichia coli.

We have demonstrated that the high resistance to imidazoles in 60 Escherichia coli strains is overcome by lowering the minimum inhibitory concentration (MIC) in culture from > 3200 to < 0.39 micrograms ml(-1) and, by determining, in contact tests, the disappearance of 10(4) CFU with 25 micrograms ml(-1) of imidazoles after 3 min. Although the contact activity was not the same as growth inhibition due to the different target of the drug in the cell structures, we annulled E. coli imidazole resistance in cultural and direct tests by means of the same non-antimicrobial conditions related to outer membrane functions.

Identification of a glucan-associated enolase as a main cell wall protein of Candida albicans and an indirect target of lipopeptide antimycotics.

Growth-subinhibitory nonlytic doses of cilofungin (lipopeptide antibiotic affecting (1,3)-beta-D-glucan synthesis) inhibited the incorporation of 46- to 48-kDa glucan-associated (46K) protein into the growing cell wall of Candida albicans. The purified 46K protein constituent strongly reacted with a monoclonal antibody against enolase, a major cytoplasmic enzyme of the fungus. In addition, two internal fragments of 12- and 15-amino acid residues from a tryptic digest of 46K protein showed 100% identity with amino acids in positions 34-45 and 66-80 of enolase. By immunoelectron microscopy with polyclonal and monoclonal anti-enolase antibodies, the 46K protein was clearly detected in the inner layers of the fungal cell wall. Thus, consistent with the proposed immunogenic and diagnostic roles of enolase in candidiasis, biochemical, immunochemical, and ultrastructural evidence strongly suggest that the cilofungin-susceptible 46K protein is a cell wall-associated form of this enzyme.

Antimicrobial activity of electrochemical silver ions in nonionic surfactant solutions and in model dispersions.

The microbicidal effectiveness against Gram-positive and Gram-negative bacteria and Candida albicans of electrochemical silver ions in aqueous solutions containing nonionic surfactants was investigated. From the perspective of the possible use of anodic silver as a preservative in cosmetic or pharmaceutical preparations, microbicidal efficacy was also studied in oil/water model dispersions. Surfactants and botanical extracts partially inhibited the microbicidal effectiveness of anodic silver. Nevertheless in all the experimental conditions, silver ions reduced the microbial concentration up to 4 log units of the starting inoculum in less than 6 h. The wide microbicidal spectrum and the high rate of kill of silver ions appear, therefore, attractive enough to suggest a possible utilization of anodic silver as a preserving agent.

Research on antibacterial and antifungal agents. XII--Synthesis and antimicrobial activity of some Mannich bases of diarylpyrroles.

The synthesis and antimicrobial activity of some Mannich bases of diarylpyrroles are reported. The obtained data show that activity is closely connected to molecular basicity. Results are discussed on the basis of structure activity relationships.

Antifungal agents, Part 11. Biphenyl analogues of naftifine: synthesis and antifungal activities.

A series of naftifine analogues having the biphenyl instead of the naphthyl moiety have been synthesized in a search devoted to study bioanalogues of clinically efficacious antifungal agents. The new derivatives were tested against Candida albicans by the direct contact method. They were also assayed against Gram-positive and Gram-negative bacteria and against some isolates of plant pathogenic fungi. Derivatives 8a, 8c, and 9a were found to be active against Candida albicans, derivative 5a was active against E. coli, a very resistant species to antimycotic agents, and derivatives 8a and 8b inhibited the plant pathogenic Rhizoctonia solani.

Study of the Mannich reaction: beta-amino-methylation of N-aryl and N-azaheteroaryl-substituted 2,5-dimethylpyrroles, compounds with potential biological activity.

Owing to the increasing need of drugs for the treatment of a variety of fungal and bacterial opportunistic infections, a study has been started with the aim of synthesizing structures amenable to a number of easily-to-perform structural modifications in order to meet the requirement of bypassing resistance phenomena. This paper reports on the synthesis of several N-(alpha-azaheteroaryl)-substituted 2,5-dimethyl-pyrroles bearing in one beta-position (or in both beta-positions) aminomethyl groups, introduced via a Mannich reaction. Electronic and steric effects by the N-(azaheteroaryl) substituents and the 2- and 5-methyl groups on the course of the Mannich reaction are discussed along with the results of in vitro tests against many Candida species, some bacteria, and several pathogenic plant fungi.