Susceptibility testing of yeasts to fluconazole by Etest and agar-diffusion disk test using the synthetic agar medium Mycoplate.

A total of 50 clinical Candida isolates was tested against fluconazole using both the Etest and the agar-diffusion disk test on the synthetic agar medium Mycoplate. Inhibition zones were readable, although a residual yeast growth occurred within the inhibition zones. The diameter of the inhibition zones in the disk test correlated very well with the logarithmically transformed minimal inhibitory concentrations measured with the Etest. For an inhibition zone diameter equal to or greater than 22 mm, using a 25 microg disk, the isolates were considered as fluconazole-susceptible, and for zone diameters less than 22 mm, dose-dependent susceptibility (S-DD) or resistance to fluconazole was assumed. These results are in agreement with those of other authors. The Mycoplate medium appeared to be suitable for testing yeasts for their susceptibility to fluconazole.

Prognostic value and clinicopathological profile of microsatellite instability in gastric cancer.

In this study, microsatellite instability (MI) was investigated in 126 gastric carcinomas and correlated with clinicopathological features and prognosis; at least 5-10 microsatellite loci were analyzed. MI was identified in 56 (44.5%) of all investigated carcinomas, one locus being affected in 40 (31.7%) carcinomas, two loci being affected in 6 (4.8%) carcinomas, and more than two loci being affected in 10 (8.0%) carcinomas. MI was correlated with neither age and sex of the patients nor with depth of invasion, lymph node metastasis, tumor differentiation, or histological type according to WHO and Laurén classification. The frequency of MI was the same in early gastric carcinomas as it was in advanced gastric carcinomas, suggesting that MI arises early during the tumorigenesis of gastric cancer. No significant differences in survival could be demonstrated between patients with MI-negative and MI-positive gastric carcinomas.

Quantitative screening for fluconazole-amphotericin B antagonism in several Candida albicans strains by a comparative agar diffusion assay.

Antagonism between fluconazole (FCZ) and amphotericin B (AMB) was determined with an agar diffusion technique using series of agar plates containing no or 10 mgl-1 FCZ (comparative diffusion assay). Serial dilutions of AMB produced concentration-dependent inhibition zones that varied between the two agar plate series. This technique served as screening method to determine FCZ-AMB interactions in 18 Candida albicans strains. The critical concentrations of AMB were enhanced 1.33- to 7.0-fold by FCZ. The critical time, T0, was reduced by half by FCZ.

Post-antibiotic effect and post-expositional polyene antagonism of azole antifungal agents in Candida albicans: dependence on substance lipophilia.

The lipophilic azoles itraconazole (ICZ), ketoconazole (KCZ) and miconazole (MCZ) have two things in common regarding their effect on Candida albicans. First, these azoles cause a growth inhibition that persists for at least 24 h after exposure (post-antibiotic effect), although this is only occasionally observed for ICZ. Secondly, these substances cause a decrease in the fungicidal activity of amphotericin B (AMB, 1 mg l-1) upon subsequent exposure to this drug. In contrast, fluconazole (FCZ) exhibits neither of these two effects. Further tests suggest that both of these phenomena observed may be related to the non-covalent binding of the three lipophilic azoles to lipophilic cytoplasmic components of yeast cells. With fluconazole, such bonds seem to be much weaker. The amount of relatively hydrophilic fluconazole that is bound non-specifically to the fungal cell is evidently too low to produce long-lasting post-exposure effects like those caused by lipophilic azoles.

Antagonistic interactions between azoles and amphotericin B with yeasts depend on azole lipophilia for special test conditions in vitro.

The interactions of the azole antifungal agents fluconazole, itraconazole, ketoconazole, or miconazole with amphotericin B (AmB) in their effect on Candida albicans were investigated. These four azoles antagonized the fungistatic activity of AmB at sub-MICs if both substances acted simultaneously. This coincubation test was primarily developed to observe the azole-mediated demethylase inhibition quantitatively by bioassay. Interestingly, the occurrence of azole-AmB antagonism depended on azole lipophilia if specially selected test conditions were applied. By a consecutive incubation regimen, preincubation at high azole concentrations (1 to 50 micrograms/ml) and then subsequent incubation with AmB (1 microgram/ml), only preincubation with the three lipophilic azoles decreased the fungicidal activity of AmB but not that of FCZ. It was shown that yeasts absorb only lipophilic azoles to a remarkable extent. This fact might be responsible for the absence of antagonism of FCZ to AmB when yeasts were incubated consecutively. It can be concluded with caution that consecutive treatment of candidiasis with FCZ and AmB does not necessarily result in a clinically relevant antagonism.

[Post-antibiotic effect and post-exposure polyene antagonism of azole antimycotics in Candida albicans: dependency on lipophilia]. / Postantibiotischer Effekt und postexpositioneller Polyen-Antagonismus von Azol-Antimykotika an Candida albicans: Abhängigkeit von der Substanz-Lipophilie.

With the lipophilic azoles itraconazole (ICZ), ketoconazole (KCZ), and miconazole (MCZ) two effects, occurring in parallel, on Candida albicans were observed: Firstly, these azoles caused a growth inhibition which persisted for at least 24 hours (post-antibiotic effect, found regularly with KCZ and MCZ, with ICZ only occasionally). Furthermore, the fungicidal activity of amphotericin B (AMB, 1 mg/1) after exposure to the azoles was reduced. In contrast, to this, fluconazole (FCZ) produced neither of these effects. Additional experiments indicate that both actions of the three lipophilic azoles may be related to their noncovalent binding to lipophilic cytoplasmatic components of the yeast cells. In the case of fluconazol such bonds seem to be much weaker. Presumably, the amount of the relatively hydrophilic fluconazole, which will be bound to the cell, is too low as to produce long lasting post-exposure effects like those caused by the lipophilic azoles.

Quantitative determination of fluconazole-amphotericin B antagonism to Candida albicans by agar diffusion.

Fluconazole is a bis-triazole antifungal which partly antagonizes the activity of amphotericin B against Candida albicans (and other Candida species). This antagonism can easily be demonstrated by radial agar diffusion. Amphotericin B at reservoir concentrations of up to 1.2 mg l-1 showed a diffusion behaviour which was described by means of a simple mathematical analysis. Therefore quantitative determination of the antagonism was possible. Using a reference strain of Candida albicans, the critical concentration of amphotericin B was increased by fluconazole up to 2.4-fold.

Successful treatment of a Candida albicans sepsis with a combination of flucytosine and fluconazole.

A case of a severe Candida sepsis is reported, which was treated successfully by a combination therapy of flucytosine with fluconazole. After an extensive abdominal operation, a 70-year-old man developed a syndrome of fulminant sepsis due to Candida albicans with the beginnings of renal failure. The latter fact forced us to search for a therapeutic alternative to the classical amphotericin B plus flucytosine combination therapy.

[Detection of Clostridium perfringens in mixed infection patient samples using a modified reverse CAMP test]. / Nachweis von Clostridium perfringens aus mischinfiziertem Patientenmaterial mittels modifiziertem reversen CAMP-Test.

Clostridium perfringes type A is the most common morbifying agent responsible for gas gangrene. For definitive bacteriological diagnosis the germ has to be isolated from contaminants. Suppression of contaminating germs by means of a selective rapid culture technique is also useful, but technical more expensive. The modification of the reverse CAMP-test demonstrated in this paper has the superiority of technical simplicity and is highly sensitive, too. By this method, Clostridia are isolated simultaneously. Thus, for submitting isolates of Clostridia to the reference laboratory, time and material are economized.

A rapid susceptibility testing method for yeasts to 5-fluorocytosine.

A rapid method of susceptibility testing of yeasts to 5-fluorocytosine is demonstrated. The method is based on photometric determination of the optical density of yeast suspensions before and after incubation for 4 h in the presence of the antifungal. The method was evaluated with 50 Candida strains.

[The microbial colonization pattern of newborn infants. What is its significance? Results of a study at a district hospital in the Gera district]. / Das mikrobielle Besiedlungsmuster Neugeborener. Welche Bedeutung kommt ihm zu? Ergebnisse einer Studie an einem Kreiskrankenhaus des Bezirkes Gera.

A microbiological investigation was performed under standardized conditions both on mother and child for total of 151 births, 112 of which being classified as normal, the remainder of 39 as risk births. Significant differences were found between the microbial colonization patterns for normal and risk births, respectively, as judged from cultures of smears from maternal cervices and from their neonates. In addition, colonization patterns of the newborn children turned out to be age-dependent. No correlation between the colonization pattern of the neonatal surface and infections of the newborn infants has been found.

Purification and characterization of the Ca2+-ATPase of plasma membranes from Ehrlich ascites mammary carcinoma cells.

Ca2+-ATPase was isolated from plasma membranes of Ehrlich ascites mammary carcinoma cells by means of calmodulin affinity chromatography. The purification procedure included removal of endogenous calmodulin from a Triton X-100 solubilizate of the membranes by DEAE ion-exchange chromatography as an essential step. With respect to its molecular mass, activation by calmodulin, Ca2+-dependent phosphorylation and highly sensitive inhibition by orthovanadate, the purified enzyme resembles the Ca2+-ATPase of erythrocyte membranes. In contrast to the strong calmodulin dependence of the isolated enzyme the Ca2+-ATPase in native Ehrlich ascites carcinoma cell membranes cannot be remarkably stimulated by added calmodulin. It is suggested that the membrane-bound Ca2+-ATPase in the presence of Ca2+ is activated by interaction with endogenously bound calmodulin.