[Evaluation of common commercial systems for the identification of yeast isolates in microbiology laboratories: a multicenter study]. / Mikrobiyoloji laboratuvarlarinda maya türlerinin tanimlanmasinda sik kullanilan ticari sistemlerin degerlendirilmesi: Çok merkezli bir çalisma.

Accurate and rapid identification of yeast isolates have become important in recent years for not only antifungal susceptibility testing due to the species-specific clinical resistance breakpoints but also early initiation of appropriate antifungal therapy. In clinical microbiology laboratories species identification of yeasts is often performed with several commercial systems based on biochemical properties and rarely according to the physiological and morphological characteristics. The aim of this study was to compare the two common commercial systems, VITEK 2 YST ID Card (Vitek; bioMérieux, France) and API 20C AUX (API; bioMérieux, France) with conventional mycological methods. A total of 473 clinical yeast strains isolated from clinical specimens in different university and training/research hospitals and identified by Vitek system were included in the study. The isolates were re-identified with API and conventional methods including morphological identification in the Mycology Reference Laboratory of the Public Health Institute of Turkey. Candida dubliniensis MYA 583, Candida krusei ATCC 6258, Candida parapsilosis ATCC 22019, Candida albicans ATCC 10231 and Cryptococcus neoformans ATCC 32268 were used as quality control strains and those standard strains were studied consecutively 10 days with both of the methods. The results of identification by Vitek and API were compared with the results of conventional methods for those 473 yeast isolates [6 genus (Candida, Cryptococcus, Blastoshizomyces, Rhodotorula, Saccharomyces, Trichosporon), 17 species (5 common and 12 rarely isolated)]. The performances of the systems were better (Vitek: 95%; API: 96%) for the commonly detected species (C.albicans, C.parapsilosis, C.glabrata, C.tropicalis and C.krusei) than those for rarely detected species (Vitek: 78.4%; API: 71.6%) (p= 0.155). Misidentification or unidentification were mostly detected for C.parapsilosis (Vitek: 6/87; API: 7/87) and C.glabrata (Vitek: 9/104; API: 3/104) by both of the systems. For rarely detected yeast isolates, misidentification or unidentification were most frequently observed in species of C.pelliculosa (Vitek: 3/11; API: 6/11) and C.dubliniensis (API and Vitek: 2/5) isolates. Candida guilliermondii (API: 2/5) isolates had lower rate of identification with API compared to other species. Blastoschizomyces capitatus and Saccharomyces cerevisiae isolates could not be identified by both of the systems. As a result, the accurate diagnosis of Vitek and API systems were similar in terms of consistency (86.3%). Two systems performed well in correct identification of common clinical yeast species (at least 95%), while the identification of rare species was more challenging indicating that they require further morphological and physiological testing. The addition of morphological identification to commercial systems will be useful for accurate diagnosis and treatment of mixed infections.

[Comparison of GeneXpert® vanA/vanB PCR system and culture methods in the surveillance of vancomycin-resistant enterococci]. / Vankomisine dirençli enterokoklarin sürveyansinda GeneXpert® vanA/vanB PCR sistemi ile kültür yönteminin karsilastirilmasi

Vancomycin-resistant enterococci (VRE) are important agents of hospital infections worldwide. Early recognition of VRE colonization is important in the control of hospital infections. The aim of this study was to compare a real-time PCR (Rt-PCR) system and culture methods in the detection of VRE colonization. A total of 210 perirectal swab samples obtained from the patients (142 were in internal and 68 were in surgical intensive care units) hospitalized at Ankara Training and Research Hospital, Turkey between January-September 2013 were included in the study. The samples were simultaneously evaluated with both Rt-PCR (GeneXpert®vanA/vanB, Cepheid, USA) and the culture methods. The samples were cultivated in enterococcosel agar and incubated at 370C for culture. Culture plates were evaluated for three days on a daily basis. Bacterial identification was done by conventional methods and automated Vitek 2.0 system (BioMérieux, France). Antibiotic susceptibility testing was performed by the E-test. VRE was detected in 76 (36.1%) of the samples by the Rt-PCR method; of them 70 were positive for vanA, two for vanB, and four for vanA + vanB. On the other hand, VRE was detected in 71 (33.8%) of the samples by the culture method. Out of 71 samples, colony growth was observed on the first day in 39 cases, on the second day in 29 cases, and on the third day in three cases. The two strains identified as vancomycin-sensitive enterococci by the Vitek 2 Compact system were determined as vanB positive by PCR. These samples were also confirmed as VRE by E-test. The PCR result of a sample which was found to be invalid, also yielded negative result by culture. Five out of the seven culture-negative samples were positive for vanA, and two for vanB by the GeneXpert® system. In our study, the sensitivity, specificity, positive and negative predictive values of the GeneXpert vanA/vanB PCR system were determined as 97.4%, 98.4%, 97.4%, and 97.4%, respectively. Although the GeneXpert® vanA/vanB RT-PCR method seems to be more attractive regarding the turn around time, it has a higher cost than the culture method. Thus, it was concluded that all laboratories should choose the most appropriate method for screening VRE in the hospital setting according to their own capacities.

Antibiotic resistance patterns of urinary tract pathogens in Turkish children.

BACKGROUND: Knowledge of local antimicrobial resistance patterns is essential for evidence- based empirical antibiotic prescribing. We aimed to investigate the distribution and changes in causative agents of urinary tract infections in children and the resistance rates, and to recommend the most appropriate antibiotics. METHODS: In this retrospective study, we evaluated causative agents and antimicrobial resistance in urine isolates from the positive community from September 2014 to April 2016 in a single hospital in Ankara, Turkey. RESULTS: A total of 850 positive urine cultures were identified, of which 588 (69.2%) were from girls and 262 (30.8%) were from boys. Their mean age was 36.5 ± 45.0 months. The most common causative agent was Escherichia coli (64.2% of cases) followed by Klebsiella pneumoniae (14.9%). The overall resistance to ampicillin (62.6%), cephalothin (44.2%), co-trimoxazole (29.8%) and cefuroxime (28.7%) was significant. No resistance to imipenem was detected in the isolates. The least resistance was for amikacin, ceftriaxone, ciprofloxacin and cefepime (0.1, 2.4, 7.5 and 8.3%, respectively). Imipenem was the most active agent against E. coli followed by amikacin (0.2%), ceftriaxone (2.7%) and nitrofurantoin (5.1%). High resistance rates to nitrofurantoin were detected in K. pneumoniae, Proteus and Enterobacteriae. CONCLUSIONS: E. coli was the most common causative agent of urinary tract infection in children. Ampicillin, trimethoprim-sulfometaxazole, cephalothin and cefuroxim had the highest resistance rates against urinary tract pathogens in our center. For oral empirical antibiotherapy, cefixime is the most appropriate choice so as to include Klebsiella strains.

A Case of Onychomycosis Caused by Rhodotorula glutinis.

Rhodotorula spp. have emerged as opportunistic pathogens, particularly in immunocompromised patients. The current study reports a case of onychomycosis caused by Rhodotorula glutinis in a 74-year-old immunocompetent female. The causative agent was identified as R. glutinis based on the pinkish-orange color; mucoid-appearing yeast colonies on Sabouraud Dextrose Agar at 25°C; morphological evaluation in the Corn Meal-Tween 80 agar; observed oval/round budding yeast at 25°C for 72 hours; no observed pseudohyphae; positive urease activity at 25°C for 4 days; and assimilation features detected by API ID 32C kit and automated Vitek Yeast Biochemical Card 2 system. Antifungal susceptibility test results were as follows: amphotericin B (MIC = 0.5 µg/mL), fluconazole (MIC = 128 µg/mL), itraconazole (MIC = 0.125 µg/mL), voriconazole (MIC = 1 µg/mL), posaconazole (MIC = 0.5 µg/mL), anidulafungin (MIC = 0.5 µg/mL), and caspofungin (MIC = 16 µg/mL). Antifungal therapy was initiated with oral itraconazole at a dose of 400 mg/day; seven-day pulse therapy was planned at intervals of three weeks. Clinical recovery was observed in the clinical evaluation of the patient before the start of the third cure. Although R. glutinis has rarely been reported as the causative agent of onychomycosis, it should be considered.