[Emerging pathogen: Candida kefyr (Kluvyeromyces marxianus)]. / Önem kazanan patojen: Candida kefyr (Kluvyeromyces marxianus).

In the central microbiology laboratory of Gazi University Hospital Candida kefyr was isolated from different clinical samples as 5.3% in 2016 and in 2017 this rate increased to 9.3% which was nearly two-fold and this has drawn our attention. The aim of this study was to evaluate the special characteristics, antifungal susceptibility and virulence properties of C.keyfr species. Germ tube, corn meal-tween 80 agar morphology and carbohydrate assimilation profiles on ID32C yeast identification system were used for the diagnosis of Candida species. In this study, DNA sequencing was performed using ITS1 and ITS4 primers amplifying fungal gene between 5.8S and 18S regions of rRNA. Antifungal susceptibility was performed using M27A microdilution method recommended by Clinical and Laboratory Standards Institute (CLSI). Minimum inhibitory concentration (MIC) values for amphotericin B, fluconazole, voriconazole and itraconazole were determined. MIC distribution, MIC50 and MIC90 values and geometric mean (GM) were detected. The existence of virulence factors caseinase, secreted aspartyl proteinase, esterase and phospholipase were investigated in vitro. A total of 865 Candida species were isolated from different clinical samples in the central microbiology laboratory of Gazi University Hospital in 2016. Among them, 46 (5.3%) were C.kefyr. In the first four months of 2017, 30 (9.3%) C.kefyr were identified among 320 Candida isolates. Ten isolates which have shown atypical morphology on corn meal agar were selected. Among these 10 isolates, nine of them were identified as C.kefyr by using ID32C system and DNA sequencing method. Amphotericin B MIC value was 2 µg/ml for one isolate, and fluconazole MIC value was 8 µg/ml for another isolate among 46 isolates. Among the 30 isolates of the year 2017, one of them presented MIC value for fluconazole as 8 µg/ml. No marked antifungal resistance was detected in our isolate group. Caseinase was positive in one C.kefyr isolate, and phospholipase were positive in eight of nine isolates. As a result, the reason of increase in the incidence of this Candida species, which does not show significant resistance and presents mostly phospholipase activity as a virulence factor, should be investigated in more detail.

[Fungicidal activity of yeast isolated from chal (camel cultured milk product)].

A Kluyveromyces strain secreting a fungicidal proteinaceous toxin has been isolated. Its maximal activity is observed at pH 5.0 and an increased osmotic pressure. This agent has been identified as a mycocin; it is active towards species belonging to the genus Kluyveromyces and some representatives of taxonomically related groups.

Comparative studies of the antioxidant effects of cis- and trans-resveratrol.

Resveratrol (3,4',5-trihydroxystilbene, RESV) is a natural phenolic compound that exists as cis and trans isomers [c-RESV or (Z)-RESV and t-RESV or (E)-RESV, respectively]. t-RESV is a natural component of Vitis vinifera L. (Vitaceae), abundant in the skin of grapes (but not in the flesh) and in the leaf epidermis, and present in wines, especially red wines. In in vitro, ex vivo and in vivo experiments t-RESV exhibits a number of biological activities, including anti-inflammatory and anticarcinogenic properties. RESV also exists in wines as a cis isomer, which (unlike t-RESV) is not currently available commercially; as a result, little is known about this isomer's pharmacological activity. In this review, I will focus on the few comparative studies of the antioxidant effects of the two RESV isomers in different experimental models.

A Kluyveromyces marxianus 2-deoxyglucoseresistant mutant with enhanced activity of xylose utilization

Thermotolerant ethanologenic yeast Kluyveromyces marxianus is capable of fermenting various sugars including xylose but glucose represses to hamper the utilization of other sugars. To acquire glucose repression-defective strains, 33 isolates as 2-deoxyglucose (2-DOG)-resistant mutants were acquired from about 100 colonies grown on plates containing 2-DOG, which were derived from an efficient strain DMKU 3-1042. According to the characteristics of sugar consumption abilities and cell growth and ethanol accumulation along with cultivation time, they were classified into three groups. The first group (3 isolates) utilized glucose and xylose in similar patterns along with cultivation to those of the parental strain, presumably due to reduction of the uptake of 2-DOG or enhancement of its export. The second group (29 isolates) showed greatly delayed utilization of glucose, presumably by reduction of the uptake or initial catabolism of glucose. The last group, only one isolate, showed enhanced utilization ability of xylose in the presence of glucose. Further analysis revealed that the isolate had a single nucleotide mutation to cause amino acid substitution (G270S) in RAG5 encoding hexokinase and exhibited very low activity of the enzyme. The possible mechanism of defectiveness of glucose repression in the mutant is discussed in this paper (AU)

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Central venous catheter infection in a child: case report and review of Kluyvera infection in children.

Kluyvera is an opportunistic pathogen that can occur in immunosuppressed as well as immunocompetent hosts. We report a case of Kluyvera species infection involving a central venous catheter, and we review the literature on Kluyvera infections in children. Our case demonstrates that removal of the central venous catheter was necessary to eradicate the infection and hasten the resolution of refractory neutropenia. The spectrum of disease due to Kluyvera infection in children includes central venous catheter infection and/or sepsis, urinary tract infection, enteritis, and, in one instance, fatal peritonitis. It is clear on the basis of our case report that uncommon, opportunistic organisms such as Kluyvera can be significant pathogens.