فهرست مطالب hristina yotova hitkova

 Vancomycin-resistant enterococci (VRE) are recognized as nosocomial pathogens with increased importance in recent years. These bacteria are frequently isolated from patients admitted to intensive care units (ICUs). Enterococcal pathogenicity is enhanced by different antibiotic resistance and virulence determinants.

 The present study aimed to assess the prevalence of genes encoding resistance to antibiotics and virulence factors in intestinal VRE isolates from ICU patients.

 In this study, 23 VREs were investigated. Minimum inhibitory concentrations (MICs) to nine antimicrobial agents were examined using E-test. Genes encoding vancomycin resistance (vanABCDMN), aminoglycoside-modifying enzymes (aac(6')-Ie-aph(2")-Ia, aph(2")-Ib, aph(2")-Ic, aph(2")-Id, aph(3')-IIIa, ant(3')-Ia, ant(4')-Ia, ant(6')-Ia), together with genes for various virulence factor (ace/acm, asa1, cylA, efaA, esp, gelE and hyl), were detected using multiplex PCR.

 The species distribution of the tested VRE was as follows: Nine Enterococcus casseliflavus, seven E. gallinarum, and seven E. faecium. The vanA gene was found in all E. faecium, in six of which the classical VanA phenotype was observed. The vancomycin (vanC) phenotype was associated with the presence of vanC1 gene in E. gallinarum and the vanC2 gene in E. casseliflavus isolates. The aac(6')-Ie-aph(2")-Ia gene was encoding high-level gentamicin resistance (HLGR) in the studied VRE. All E. faecium were positive for acm and esp, while acm in combination with esp or hyl was detected in 2 vanC enterococci.

 According to the findings, there was a correlation between the phenotype and the genotype of glycopeptide resistance in the tested VRE. HLGR was more prevalent in E. faecium because of the presence of aac(6')-Ie-aph(2")-Ia. The higher prevalence of virulence determinants was confirmed in vanA isolates compared to the studied vanC-carrying enterococci.

 Emerging non-albicans Candida (NAC) species are a major threat because of their intrinsic or acquired resistance to routinely applied antifungal agents.

 The purpose of our study was to reveal in vitro activity of nine antifungal agents against NAC isolates.

 A total of 67 NAC (27 Candida glabrata, 10 C. tropicalis, 6 C. krusei, 6 C. parapsilosis, 4 C. lusitaniae, 4 C. lipolytica, etc.) were identified and tested. The antifungal susceptibility was estimated on the basis of minimum inhibitory concentrations (MIC).

 Overall, 13 species were determined, of which C. glabrata was the most common (40.3%), followed by C. tropicalis (14.9%), C. krusei, and C. parapsilosis (8.9 % each). Forty-nine NAC isolates (73.13%) demonstrated decreased susceptibility to one or more antifungals, and 18 of them were resistant to all azoles. Out of 27 C. glabrata, 12 (44.4%) were resistant to fluconazole with MICs: 32 - >128 µg/mL and 15 (55.6%) were intermediate with MICs: 8 - 16 µg/mL Non-albicans Candida revealed a good susceptibility to echinocandins. Amphotericin B resistance was found in 5.97% of the isolates. Of particular interest was the detection of 6 (8.95%) multidrug-resistant NAC, which expressed resistance to azoles and echinocandins and/or amphotericin B.

 About one-fourth of the studied NAC were resistant to all azoles. These findings as well as the detection of several multidrug-resistant isolates determine the necessity of susceptibility testing of clinically important yeast isolates and control of the antifungal drugs in our hospital.
 

The precise identification of yeasts and their antifungal sensitivity is a key factor in the choice of a suitable drug for treatment and prevention of fungal infections. The aim of the present study was to determine in vitro susceptibility of clinical Candida albicans isolates to nine antifungal agents. A total of 61 C. albicans isolates were tested. Antifungal susceptibility was evaluated by determination of minimum inhibitory concentrations (MIC). Fifty C. albicans isolates were susceptible to nine antifungal agents. The remaining 11 yeasts were resistant to one ormoreantifungals. All C. albicans were susceptible to amphotericin B with MICs 0.25 to 1 g/mL and exhibited sensitivity to 5-fluorocytosine with MIC90 of 0.125 g/mL. The MIC50 and MIC90 of fluconazole were 0.5 and 32 g/mL, whereas the MIC50 and MIC90 of voriconazole were considerably lower - 0.0078 and 2 g/mL. The isolates showed susceptibility to echinocandins with MIC90 of micafungin, anidulafungin and caspofungin of 0.015, 0.031, and 0.125g/mL, respectively. Of particular interest was detection of seven C. albicans isolates, which expressed a high-level resistance to all azoles and one of them was also resistant to echinocandins. In conclusion, detection of resistance in C. albicans, which is a species typically susceptible to antifungals, is of great importance for clinical practice.