Authors:Ilona Dóczi, Gy. Mestyán, Erzsébet Puskás, Radka Nikolova, I. Barcs, and Elisabeth Nagy
The ARTEMIS Global Antifungal Susceptibility Program provides the collection of epidemiological data and the results of the fluconazole and voriconazole susceptibility testing of yeast isolates. Participating in this study, a total of 7318 clinical yeast isolates were tested from different geographical areas in Hungary in the period 2001 to 2003. The species isolated most frequently was C. albicans (68.8%), followed by C. glabrata (11.8%), C. tropicalis (5.7%) and C. krusei (4.6%). Isolates of C. albicans, C. kefyr, C. lusitaniae, C. tropicalis and C. parapsilosis were highly susceptible to fluconazole (78.9-100%). The rates of isolation of fluconazole-resistant C. glabrata and C. krusei were higher in our study than the global mean in 2001 (28.2% and 87.5% vs. 18.3% and 70.2%, respectively). Differences were detected in the distribution of fluconazole-susceptibility data of C. glabrata isolates in the different counties of Hungary: most of the resistant isolates were observed in the eastern part of the country.
Authors:L. Kredics, Zsuzsanna Antal, A. Szekeres, L. Manczinger, Ilona Dóczi, F. Kevei, and Elisabeth Nagy
Species belonging to the filamentous fungal genus Trichoderma are well known as potential candidates for the biological control of plant pathogenic fungi and as cellulase producers of biotechnological importance. Several data were published in the last decade also about the clinical importance of this genus, indicating that Trichoderma strains may be potential opportunistic pathogens in immunocompromised patients. However, there is a lack of information about the potential virulence factors of clinical Trichoderma strains. This study was designed to examine the extracellular proteolytic enzymes of six clinical T. longibrachiatum isolates. Supernatants from induced liquid cultures of the examined strains were screened for proteolytic enzyme activities with 11 different chromogenic p-nitroaniline substrates. The production of trypsin-like, chymotrypsin-like and chymoelastase-like protease activities cleaving N-Benzoyl-L-Phe-L-Val-L-Arg-p-nitroanilide, N-Succinyl-L-Ala-L-Ala-L-Pro-L-Phe-p-nitroanilide,and N-Succinyl-L- Ala-L-Ala-L-Pro-L-Leu-p-nitroanilide, respectively, was common among the strains examined. Separation of trypsin- and chymotrypsin-like activities by column chromatography revealed, that both systems are complex consisting of several isoenzymes. The pH-dependence of these two protease systems was also studied. Based on the results, the different isoenzymes seem to have different optimal pH values. Extracellular proteolytic enzymes may be involved in the pathogenecity of Trichoderma strains as facultative human pathogens.
Authors:Erika Dósa, Ilona Dóczi, L. Mojzes, Etelka G. Molnár, J. Varga, and Erzsébet Nagy
The fungal revolution taking place in otorhinology inspired us to study the frequency of occurrence of fungi in the nasal mucus of chronic rhinosinusitis (CRS) patients (with or without polyposis) in order to evaluate the incidence of eosinophilic fungal sinusitis in CRS patients. Ninety-six samples were examined from patients with CRS. In 74 cases mucus was collected non-invasively, and in 22 cases during operation. The Gram-stained direct smears of all samples were also evaluated. Bacteria and fungi colonizing in the mucus were detected by culturing method. The control group consisted of 50 healthy volunteers. Typical aerobic pathogenic bacteria could be isolated from 34 patients. Fifty-seven aerobic bacteria were isolated, i.e. 1.6 bacteria/positive patient with a maximum of 3 different bacteria/sample. The most frequently isolated bacteria were Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Streptococcus pneumoniae, and Haemophilus influenzae. Yeasts and moulds could be detected from 79 patients (83%): Candida albicans, Candida spp., Aspergillus spp., Cladosporium spp, and Penicillium spp. were isolated most frequently. Altogether 237 yeasts and moulds were isolated, i.e. 3.0 different fungi/positive patient, with a maximum of 5 different fungi/sample. In the control group aerobic pathogens were not isolated, only apathogenic species. Fungi were isolated from 22 healthy patients (44%). These data indicate that fungi are frequently involved in the aetiology of CRS. IgE-mediated hypersensitivity to fungal allergens could not be proven in our patients.
Authors:Ilona Dóczi, Erika Dósa, J. Varga, Zsuzsanna Antal, L. Kredics, and Elizabeth Nagy
The purpose of this study was to evaluate the Etest as an in vitro antifungal susceptibility test method for different moulds originating from human samples and from the environment. A total of 50 isolates (1 Acremonium, 18 Aspergillus, 2 Cladosporium, 1 Epicoccum, 15 Penicillium, 2 Scopulariopsis and 11 Trichoderma strains) were tested by the Etest. Forty-six of the tested moulds (92%) were resistant to fluconazole with minimal inhibitory concentrations (MICs) ³ 256 µg ml-1. There were strains resistant to ketoconazole among Aspergillus niger, A. ochraceus and Cladosporium spp. with MICs ? 32 µg ml-1. For fluconazole, no differences were observed using two different inocula, while for itraconazole, ketoconazole and amphotericin B, a 1 or less step 2-fold dilution difference in MIC was seen for the most of 10 selected strains. The MICs of fluconazole and amphotericin B obtained for Trichoderma strains by the Etest and the agar dilution method were also compared. MICs for fluconazole were in agreement, while MICs for amphotericin B were higher with 1 or 2 steps of 2-fold dilutions for most of Trichoderma strains in the case of the agar dilution method.
Authors:L. Kredics, Zsuzsanna Antal, Ilona Dóczi, L. Manczinger, F. Kevei, and Elisabeth Nagy
Cefditoren is the active form of cefditoren pivoxil, a new, broad-spectrum oral cephalosporin with strong in vitro activity against penicillin-susceptible and resistant Streptococcus pneumoniae. In this study, the minimum inhibitory concentrations (MICs) of cefditoren were determined for a special selection of S. pneumoniae isolates known to be susceptible, moderately susceptible or fully resistant to penicillin; these isolates originated from the lower respiratory tract of adults with pneumonia or the upper respiratory tract of children with or without symptoms of infection. Some of this latter group of isolates exhibited extremely high MICs to penicillin (³32 mg/l), whereas the MICs of cefditoren did not exceed 2 mg/l. The MIC50 and MIC90 of cefditoren proved to be 0.25 and 1.0 mg/l, respectively, with a range of MICs £0.015-2.0 mg/l for all the tested S. pneumoniae isolates. Its good activity suggests that cefditoren is expected to be a potent drug in infections caused by penicillin-resistant and multidrug-resistant S. pneumoniae.
Authors:Ilona Dóczi, Zoltán Pető, Eleonóra Fodor, László Bereczki, Elisabeth Nagy, and Edit Hajdú
The incidence of Candida species causing bloodstream infections in the University Hospital of Szeged, Hungary, between 1996 and 2009, and the susceptibilities of these isolates to antifungal agents were evaluated.Automated blood culture systems (Vital, bioMérieux, Marcy-l’Etoile, France; and BACTEC 9120, Becton-Dickinson Diagnostic Systems, Sparks, USA) were used. The in vitro susceptibilities of the yeast isolates to antifungal agents were determined by the Etest method (AB Biodisk, Solna, Sweden).Bloodstream infections were caused by yeast strains in 231 cases during this period, and 226 Candida strains were cultured from 216 candidaemia patients. Bloodstream infections caused by multiple Candida spp. were diagnosed almost every year. Of the 216 patients, 67 were children; and 55 infants needed intensive care. In 2005, C. glabrata caused an increase in the incidence of invasive fungal infections in the Neonatal Intensive Care Unit. The PFGE analysis of 12 isolates distinguished 4 different karyotypes. The incidence of bloodstream infections caused by fungi did not change during the 14-year study period. The most frequent species cultured from blood samples were C. albicans and C. glabrata. The incidence of resistant isolates remained constant. The local trends of fungaemia must be monitored and compared with global reports.
Authors:Zsuzsanna Antal, L. Kredics, J. Pakarinen, Ilona Dóczi, Maria Andersson, Mirja Salkinoja-Salonen, L. Manczinger, A. Szekeres, L. Hatvani, C. Vágvölgyi, and Elisabeth Nagy
Potential virulence factors of 9 saprophytic and 12 clinical Trichoderma longibrachiatum strains were examined in the present study, in order to compare their capacity to cause infection in humans. All of the strains were able to grow at temperatures up to 40 °C and at pH values ranging from 2.0 to 9.0. Carbon and nitrogen source utilization experiments revealed that all of the strains were able to utilize a series of basic amino acids both as sole carbon and nitrogen sources. The MIC values of the tested antifungal drugs were found to be 0.016-8 µg/ml for amphotericin B, 64-256 µg/ml for fluconazole, 0.5-32 µg/ml for itraconazole and 0.008-1 µg/ml for ketoconazole in the case of the examinedis olates. Metabolites of the strains inhibited the growth of different bacteria, furthermore, compounds produced by three clinical isolates reduced the motility of boar spermatozoa, indicating their toxicity to mammalian cells as well. On the whole, there were no significant differences in the examined features between strains derived from clinical or soil samples. The question, however, whether all environmental Trichoderma longibrachiatum strains have the capacity to cause infections or not, remains still unanswered.