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ABSTRACT: Nineteen clinical isolates ofCandida albicans andC. dubliniensis were isolated from patients (majority of them HIV-positive) in Slovakia, Brazil, Thailand and Japan. Species discrimination
was performed by using growth on CHROMagar Candida, commercial biochemical set API 20C AUX, germ-tube test in human serum,
growth at 42 and 45°C on Sabouraud-dextrose agar as well as on CHROMagar Candida, assimilation ofd-xylose and methyl α-d-glucoside by glass-tube test, and production of chlamydospores. These tests were completed by PCR using Cd-oligo2/F and Cd-oligo2/R
primer pair specific forC. dubliniensis. Six clinical isolates were confirmed to beC. dubliniensis, remaining 13 strains were determined asC. albicans. The use of conventional method showed that the determination is markedly influenced by personal evaluation suggesting the
necessity of using the combination of many tests to obtain correct results comparing with accurate and rapid PCR assay. For
discrimination betweenC. albicans andC. dubliniensis we recommend the combination of primo-cultivation on CHROMagar, followed by germ-tube test and PCR.
Folia Microbiologica 04/2012; 49(4):484-490. · 0.68 Impact Factor
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ABSTRACT: Occurrence and transferability of β-lactam resistance in 30 multi-resistantEscherichia coli, Klebsiella spp.,Enterobacter spp.,Pantoea agglomerans, Citrobacter freundii andSerratia marcescens strains isolated from children between 0 and 3 years of age is presented. The strains were resistant to ampicillin (30),
cefoxitin (22), cefotaxime (30), ceftriaxone (30), ceftazidime (30) and aztreonam (28), but susceptible to cefepime (30) and
imipenem (26). Twenty-eight of 30 isolates possessed a transferable resistance confirmed by conjugation and isolation of 79–89-kb
plasmids. The β-lactam resistance was due to production of β-lactamases and ceftazidime proved to be stronger β-lactamase
inductor than ceftriaxone. Twenty-five clinical isolates expressed transferable extended spectrum β-lactamases, and chromosomally
encoded AmpC β-lactamase.
Folia Microbiologica 04/2012; 46(4):339-344. · 0.68 Impact Factor
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ABSTRACT: Enterococcus faecalis and E. faecium are grampositive commensal bacteria that may become pathogenic under the selection pressure. In view of natural resistance and effective mechanisms of genetic transfer, the treatment of enterococcal diseases is rather complicated. Aminoglycosides are clinically relevant antimicrobials that are frequently prescribed in practice since having good pharmacokinetics and showing synergism with beta-lactam and glycopeptides. One of the major mechanisms involved in aminoglycoside resistance is inactivation of the antibiotic agent by aminoglycoside-modifying enzymes (AGMEs) differing in the capacity for inactivation of specific types of aminoglycosides. The factors of virulence are also involved in enterococcal pathogenicity but their role in the pathogenesis of infectious diseases remains unclear. Production of beta-hemolysin (Hly), gelatinase (Gel), and aggregation substance (AS), and synthesis of enterococcal surface protein (Esp) are among the most frequently studied potential virulence factors.
Epidemiologie, mikrobiologie, imunologie: casopis Spolecnosti pro epidemiologii a mikrobiologii Ceske lekarske spolecnosti J.E. Purkyne 05/2005; 54(2):65-74.
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ABSTRACT: This study presents the efficiency of the experimental antifungal agents 6-amino-2-n-pentylthiobenzothiazole (APB) and the echinocandin micafungin, and amphotericin B against fluconazole-resistant Candida albicans and Candida dubliniensis (MIC95 for fluconazole > 64 mg/l). The benzothiazole APB was less active against C. albicans and C. dubliniensis (MIC80 = 8 - 32 mg/l, MIC95 = 16 - 64 mg/l) than amphotericin B, which was efficient in a concentration range from 0.125 to 2 mg/l. However, the efficiency of micafungin was very high with MIC80, and MIC100 < or = 0.031 mg/l.
Pharmazie 07/2004; 59(7):573-4. · 1.01 Impact Factor
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ABSTRACT: Nineteen clinical isolates of Candida albicans and C. dubliniensis were isolated from patients (majority of them HIV-positive) in Slovakia, Brazil, Thailand and Japan. Species discrimination was performed by using growth on CHROMagar Candida, commercial biochemical set API 20C AUX, germ-tube test in human serum, growth at 42 and 45 degrees C on Sabouraud-dextrose agar as well as on CHROMagar Candida, assimilation of D-xylose and methyl alpha-D-glucoside by glass-tube test, and production of chlamydospores. These tests were completed by PCR using Cd-oligo2/F and Cd-oligo2/R primer pair specific for C. dubliniensis. Six clinical isolates were confirmed to be C. dubliniensis, remaining 13 strains were determined as C. albicans. The use of conventional method showed that the determination is markedly influenced by personal evaluation suggesting the necessity of using the combination of many tests to obtain correct results comparing with accurate and rapid PCR assay. For discrimination between C. albicans and C. dubliniensis we recommend the combination of primo-cultivation on CHROMagar, followed by germ-tube test and PCR.
Folia Microbiologica 02/2004; 49(4):484-90. · 0.68 Impact Factor
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ABSTRACT: Extended-spectrum beta-lactam antibiotics have found great medical importance, but their wide use in clinical practice leads to increasing resistance to them. The more frequent occurrence of infections caused by Bush group 1 beta-lactamase producing organisms, including species of the genus Enterobacter, is a serious problem in this field. Resistance to beta-lactams in this important nosocomial pathogens can be due to 1) reduction in outer membrane permeability to antibiotics caused by alterations in outer membrane lipopolysacharides or proteins (porins); 2) production of beta-lactamases, which inactivate beta-lactams and can also lead to resistance by non-hydrolytic mechanism called trapping. Production of plasmid-mediated extended-spectrum beta-lactamases, but especially chromosomally-mediated inducible cephalosporinase AmpC, which can be synthesized constitutively in large amounts as consequence of spontaneous chromosomal mutations, are of great clinical importance. Fourth-generation cephalosporins and carbapenems are the most effective in the treatment of infections caused by species belonging to the genus Enterobacter, but combination of high level beta-lactamase production and decreased outer membrane permeability, which is not rare in Enterobacter spp., leads to resistance even to these drugs.
Epidemiologie, mikrobiologie, imunologie: casopis Spolecnosti pro epidemiologii a mikrobiologii Ceske lekarske spolecnosti J.E. Purkyne 09/2001; 50(3):121-30.
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ABSTRACT: The influence of the Cu(II)-complexes of thiophene oligomers synthesized by oxidative polymerization of thiophene with Cu2+ ions in ZSM-5 zeolite channels on fungicidal and antimicrobial properties was studied. It has been found that the heterogeneous system culture medium-modified zeolite increases sporulation of the tested fungus (Aspergillus niger) and concurrently kills yeast (Candida albicans). These effects are attributed to a slow release of Cu2+ ions and thiophene oligomers into the culture medium. As for the tested bacteria (G+ Staphylococcus aureus, G- Escherichia coli), the percentage of the killed cells increases due to light activation of the system. The light effect is assigned to photogeneration of the reactive oxygen species (ROS), mainly *OH radicals, which were registered in the water solution by EPR spectroscopy. It has been confirmed that the thiophene oligomers present in the Cu-ZSM-5 microstructure slow down the release of copper into the medium.
Chemosphere 08/2001; 44(3):313-9. · 3.21 Impact Factor
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ABSTRACT: Occurrence and transferability of beta-lactam resistance in 30 multi-resistant Escherichia coli, Klebsiella spp., Enterobacter spp., Pantoea agglomerans, Citrobacter freundii and Serratia marcescens strains isolated from children between 0 and 3 years of age is presented. The strains were resistant to ampicillin (30), cefoxitin (22), cefotaxime (30), ceftriaxone (30), ceftazidime (30) and aztreonam (28), but susceptible to cefepime (30) and imipenem (26). Twenty-eight of 30 isolates possessed a transferable resistance confirmed by conjugation and isolation of 79-89-kb plasmids. The beta-lactam resistance was due to production of beta-lactamases and ceftazidime proved to be stronger beta-lactamase inductor than ceftriaxone. Twenty-five clinical isolates expressed transferable extended spectrum beta-lactamases, and chromosomally encoded AmpC beta-lactamase.
Folia Microbiologica 02/2001; 46(4):339-44. · 0.68 Impact Factor
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ABSTRACT: The transferability and expression of beta-lactam resistance were compared in multiresistant clinical isolates of Enterobacter spp. collected from different hospitals in Bratislava, Slovakia (n = 15) and Innsbruck, Austria (n = 19) during 1996-1997. The strains from Bratislava were resistant to ampicillin, cefoxitin, cefotaxime, ceftazidime and ceftriaxone. All strains from Innsbruck were resistant to ampicillin and cefoxitin; 17 were also resistant to ceftazidime and aztreonam but the majority remained susceptible to cefotaxime and ceftriaxone. All strains were susceptible to cefepime and imipenem. The majority of the tested strains transferred resistance determinants to E. coli recipient by conjugation. Production of beta-lactamase including ESBL was the major mechanism of beta-lactam resistance. Large plasmids of 77-88 and 91 kb were confirmed in clinical isolates from Bratislava and Innsbruck.
International Journal of Antimicrobial Agents 10/2000; 16(1):31-6. · 4.13 Impact Factor
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International Journal of Antimicrobial Agents 08/2000; 15(2):153-4. · 4.13 Impact Factor
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ABSTRACT: The influence of six antifungal agents on the expression of the fungal iC3b binding protein was studied in germ-tubes and the mycelial form of several Candida albicans strains. All antifungal agents inhibited not only the yeast-mycelial transformation, but also the formation of rosettes consisting of complement-coated sheep erythrocytes (EAiC3b) bound to the mycelial form of C. albicans. Immunofluorescence as well as ELISA, employing the monoclonal antibody OKM-1 which recognizes the alpha chain of human CR3 and which cross-reacts with the fungal iC3b binding protein, revealed that subinhibitory concentrations of 0.1 mg l(-1) (which did not affect the growth of either germ-tubes or the mycelial form of C. albicans) inhibited the expression of the iC3b binding protein, while lower concentrations (0.01 mg l(-1)) allowed a comparable and sometimes even slightly higher expression of this protein, in comparison with the untreated control. However, treatment with antifungal agents apparently did not lead to a major cleavage of the protein. The dependence of the amount of the iC3b binding protein expressed on the concentration of added antifungal drugs and on the morphological forms of individual C. albicans isolates suggests a drug dependent influence on the expression of this protein and a possible association with the changing virulence of C. albicans strains during antifungal therapy.
FEMS Immunology & Medical Microbiology 11/1999; 26(1):1-10. · 2.44 Impact Factor
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ABSTRACT: Three representative Candida albicans strains were selected out of 26 clinical isolates and strains from culture collections on the basis of their high level of conversion to germ tubes and mycelial form at mycelium-promoting culture conditions, and on their different sensitivity to 6-amino-2-n-pentylthiobenzothiazole (APB). When these strains were treated with APB at mycelium-promoting culture conditions, a concentration-dependent decrease in the proportion of germ tubes and hyphae was observed, while the proportion of the yeast from increased. When non-saponifiable lipids were extracted from these cultures and analyzed, a concentration-dependent decrease in ergosterol and an increase in 4-methylated sterols was observed. However, the sensitivity of sterol biosynthesis did not directly relate to the sensitivity of the morphological conversion, and was exhibited at higher concentrations of APB. On the basis of these results it is suggested that the inhibition of germ tube formation and filamentation is not a consequence of inhibition of ergosterol biosynthesis in APB-treated C. albicans.
Folia Microbiologica 02/1999; 44(5):523-6. · 0.68 Impact Factor
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ABSTRACT: Mechanisms and transferability of beta-lactam resistance in 50 ceftazidime resistant strains of Enterobacteriaceae was studied. These strains were selected from 1991 E. coli, 1035 Enterobacter spp., 168 Citrobacter spp. and 1371 Klebsiella spp., isolated from patients hospitalized in ICUs and in the pediatric and urology departments of six hospitals in Bratislava during the years 1994-1996. The selected strains expressed the resistance not only to ceftazidime (50/50) but also to ampicillin (50/50), ceftriaxone (50/50), cefotaxime (49/50) and cefoxitin (45/50). The mechanism of resistance in all 50 strains was the production of beta-lactamases by conjugation, using either ceftazidime or cefotaxime for the selection of transconjugants and by isolation of R-plasmids ranging from to 55-87 kb from donor strains and from transconjugants. A total of 21 isolates possessed chromosomally encoded resistance and 25 clinical isolates and their transconjugants expressed ESBL sensitive to clavulanate. Selected E. coli and Klebsiella pneumoniae isolates expressed the presence of TEM and SHV enzymes determined by isoelectric focusing. The possible trends in the development of antimicrobial resistance in Slovakia in the future are indicated.
International Journal of Antimicrobial Agents 06/1998; 10(2):135-41. · 4.13 Impact Factor
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ABSTRACT: Beta-lactams are considered to be very important drugs used in the therapy of many serious bacterial infections. In the last few years, the number of isolated clinical strains from the Enterobacteriaceae family, mainly Enterobacter and Klebsiella spp. resistant to 3rd generation cephalosporins, rapidly increased. Resistance can be located on chromosomes or be determined by plasmids and transposons. The production of beta-lactamases is the most frequent manifestation of beta-lactam resistance. Spread of such resistance, especially plasmid-encoded, is believed to be a serious risk factor. Therefore the study of the resistance mechanism is Gram-negative bacilli to beta-lactams not only indicates the present situation, but also trends in future medical therapy.
Epidemiologie, mikrobiologie, imunologie: casopis Spolecnosti pro epidemiologii a mikrobiologii Ceske lekarske spolecnosti J.E. Purkyne 06/1997; 46(2):73-80.
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Pharmazie 09/1996; 51(8):606-8. · 1.01 Impact Factor
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ABSTRACT: Candida albicans has become one of the most important pathogens in intensive care units. Adherence of C. albicans to the vascular endothelium is believed to represent a critical step in the pathogenesis of disseminated candidiasis and may involve molecules analogous to human beta 2-integrins such as the complement receptor 3 (CR3) analogue of C. albicans (C.a.-CR3). Its expression was detected by a sensitive rosetting assay when Candida was present in its hyphal form but not in its yeast form, the latter being generally considered to be less pathogenic. However, the presence of hyphae alone was not sufficient: C.a.-CR3 expression was found to be temperature-dependent for 4 (out of 10) clinical isolates. Two rosetted better after growth at 30 degrees C, the other 2 after growth at 37 degrees C. This temperature dependence was most pronounced for 1 laboratory strain: C.a.-CR3 expression was best at 30 degrees C and markedly decreased with increasing temperatures. At 37 degrees C no rosettes were detected at all. Modifications of the culture conditions (e.g. agitation, pH) exerted a marked influence on the morphology of this strain but always allowed rosette formation once hyphae were formed at 30 degrees C. However, none of these modifications was able to induce rosettes at 37 degrees C. Adhesion of C. albicans isolates to an endothelial cell line was also temperature-dependent but not strongly correlated with C.a.-CR3 expression. Most strains exhibited a better adherence when grown at 30 degrees C. This finding may be of importance for exogenous infections, with Candida spp. invading the body from the outside, where the temperature is usually lower than the physiological body temperature.
Experimental and Clinical Immunogenetics 02/1996; 13(3-4):161-72.
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ABSTRACT: The effects of 6-amino-2-n-pentylthiobenzothiazole (APB), a new antifungal agent, on ergosterol biosynthesis in Candida albicans and Saccharomyces cerevisiae were studied, using [14C]acetate incorporation. In C. albicans, the inhibition of growth was accompanied by a marked inhibition of acetate incorporation in 4-desmethylsterols, with a significant portion of the radiolabel being incorporated in 4,4-dimethylsterols, lanosterol, and 4,4-dimethylzymosterol and minor amounts being incorporated in 4-methylsterols and squalene. The data are interpreted as evidence of a block of the ergosterol biosynthesis pathway at the level of 4-demethylation of 4,4-dimethylzymosterol, with partial inhibition of lanosterol 14-dimethylation and squalene epoxidation also being possible. In 6-amino-2-n-pentylthiobenzothiazole-treated S. cerevisiae, a significant amount of the radiolabel was incorporated also in 4-methylsterols, 4-methylzymosterol, and 4-methylfecosterol, indicating that in this microorganism there are different sensitivities of the two 4-demethylations and that the pathway is blocked at the level of 4-demethylation of 4-methylsterols.
Antimicrobial Agents and Chemotherapy 08/1995; 39(7):1538-41. · 4.84 Impact Factor
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ABSTRACT: In vitro and in vivo antifungal activities of synthetically parepared 6-amino-2-n-pentylthiobenzothiazole (APB) against Trichophyton strains were studied. APB inhibited the growth of 3 Trichophyton strains at 65 micrograms/ml. 2-Mercaptobenzothiazole was not effective at 125 micrograms/ml and ketoconazole inhibited the growth at 20-30 micrograms/ml. Treatment of experimental dermatophytosis in guinea pigs using 2.5% APB cream was studied in comparison to Canesten cream (1% clotrimazole). Dermatophytosis was considerably reduced after both APB and Canesten therapies.
Mycopathologia 07/1995; 130(3):141-5. · 1.65 Impact Factor
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Pharmazie 07/1995; 50(6):440-1. · 1.01 Impact Factor
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Pharmazie 03/1995; 50(2):156. · 1.01 Impact Factor
