Ayse Nedret Koc

Erciyes Üniversitesi, Caesarea, Kayseri, Turkey

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Publications (32)48.49 Total impact

  • M A Atalay, A N Koc, G Demir, H Sav
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    ABSTRACT: Background: The Candida species, which are one of the most common causes of nosocomial bloodstream infections, present with high mortality and morbidity rates. This study aims to investigate the production of esterase, phospholipase, proteinase, and biofilm formation ability of the Candida strains isolated from the blood cultures. Materials and Methods: Between June 2011 and July 2012, the Candida strains, which were isolated from blood cultures of a total of 50 patients, were studied. The esterase activity was analyzed in the Tween-80 agar, while phospholipase activity was studied in the egg yolk agar. The proteinase activity and biofilm formation were identified by using the petri dish method and microplate method, respectively. Results: Of 50 specimens obtained from individual patients, 17 (34%) were identified as C. albicans, 14 (28%) as C. glabrata, 9 (18%) as C. parapsilosis, 5 (10%) as C. krusei, 4 (8%) as C. kefyr, and 1 (2%) as C. tropicalis. The rate of proteinase, phospholipase, and esterase positivity was higher in the C. albicans isolates. Biofilm formation was the highest in the C. parapsilosis strains. Conclusions: Higher rate of virulence factors in the most commonly isolated Candida species than other species indicates that these virulence factors play a crucial role in the pathogenesis.
    Nigerian journal of clinical practice 01/2015; 18(1):52-55. · 0.26 Impact Factor
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    ABSTRACT: Phaeohyphomycosis is a term used to define infections caused by darkly pigmented fungi with septate hyphae which contain melanin in their cell walls. Although fungi rarely cause central nervous system (CNS) infections, the incidence of CNS infections caused by melanin-containing fungi has been increasing in the recent years. Cladophialophora bantiana is the most frequently isolated species from cerebral phaeohyphomycosis. It mostly affects adult men in the second and third decade of life and about half of the cases occurs in immunocompetent patients. In this report, the isolation of C.bantiana from brain tissue of an immunocompetent patient who was operated with the initial diagnosis of a brain abscess, was presented. A 27 year-old male patient presenting without any chronic disease was admitted to the emergency department of our hospital with the complaints of persistent headache and diplopia. Magnetic resonance imaging (MRI) showed a space-occupying lesion in the right parietal lobe and left frontal lobe. Brain abscess was diagnosed in the patient who was referred to the neurosurgery department. Treatment was initiated with ceftriaxone and metronidazole. The abscess material sent for direct microscopic examination in the mycology laboratory was stained with Gram and Giemsa and cultured in the Sabouraud dextrose agar medium (SDA) with and without antibiotics (cycloheximide and chloramphenicol). Then, it was incubated at 37°C and 25°C. Direct examination and staining revealed a septate hyphae. The patient who received liposomal amphotericin B was referred to the infectious diseases department. Surface colors of all media including SDA with cycloheximide were olive-gray to black and contained velvety colonies. Lemon-like very long and integrated chains of conidium with poor branching in cornmeal Tween 80 agar, as well as growth at 42°C in passages, positive urease test result and cycloheximide resistance suggested C.bantiana. The isolate was confirmed as C. bantiana based on its DNA sequence analysis. Minimum inhibitor concentration (MIC) values for amphotericin B, voriconazole, caspofungin, and posaconazole were 2 µg/ml, 0.03 µg/ml, 0.03 µg/ml and 0.03 µg/ml, respectively. Liposomal amphotericin B was replaced with voriconazole due to the antifungal susceptibility profile. The patient who was symptom-free was discharged at 24 days after hospitalization with oral voriconazole treatment. In conclusion, cerebral phaeohyphomycosis should be considered in immunocompetent individuals. Given the fact that early diagnosis saves lives, such specimens should promptly be sent for mycological analysis.
    Mikrobiyoloji bülteni 07/2014; 48(3):501-506. · 0.61 Impact Factor
  • Mustafa Altay Atalay, Ayşe Nedret Koc
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    ABSTRACT: Scedosporium apiospermum is a saprophytic fungus which is isolated worldwide in soil, fertilizers, polluted water, rotten vegetables, and other natural environments. It is the cause of mycetoma, a subcutaneous infection, characterized by granule formation. It may also cause severe local or diffuse infections in immunosuppressive patients. S.apiospermum-induced arthritis, endocarditis, keratitis, scleritis, endophthalmitis, meningitis, osteomyelitis, otomycosis, onychomycosis, chronic prostatitis, peritonitis, esophagitis, renal infection, and hepatosplenic abscess have been previously reported in the literature. Possible risk factors of fungal keratitis, one of the major causes of fungal ocular infection, include ocular injury, long-term therapy with topical or systemic steroids, immunosuppressive agents, and underlying diseases such as pre-existing corneal surface abnormality and diabetes mellitus, and wearing contact lenses. We paid great attention to the case report presented by Kalkan Akçay E et al. titled "Fungal keratitis caused by Scedosporium apiospermum: first report from Turkey", which was published in the October 2013 issue of Bulletin of Microbiology [Mikrobiyol Bul 2013; 47(4): 727-33]. Although it is deemed as the first case report of S.apiospermum-related fungal keratitis in Turkey, there were several previous case reports of ocular infections associated with this type of fungus in Turkey, including those of Yucel A titled "An eye mycosis caused by Scedosporium apiospermum (Monosporium apiospermum)" published in 1989, Kiratli et al. titled "Scedosporium apiospermum chorioretinitis" in 2001, Saracli et al. titled "Scedosporium apiospermum keratitis treated with itraconazole" in 2003 and Erdem et al. titled "Clinical follow up of a keratomycosis case with total corneal melting" in 2005. In conclusion, it should be highlighted that the report of Kalkan Akcay et al. is not the first case report of Scedosporium apiospermum-related fungal keratitis in Turkey. We believe, hence, that correction of this misinformation would be beneficial for further studies.
    Mikrobiyoloji bülteni 04/2014; 48(2):362-3. · 0.61 Impact Factor
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    ABSTRACT: Pneumocystis jirovecii pneumoniae (PJP) may be difficult to diagnose. Since pneumocystis cannot be cultured, the diagnosis of PJP requires microscopic examination to identify pneumocystis from induced sputum or bronchoalveolar lavage (BAL) fluid. In order to evaluate the usefulness of (1-3) beta-D-glucan (BDG) levels in the early diagnosis of PJP, we describe the case of PJP in a 25-year-old male with acute lymphoblastic leukaemia (ALL) admitted to hospital with progressive dyspnea and fever with chills. The patient was not infected with human immunodeficiency virus (HIV). Sputum, blood, and urine cultures were negative; smears for acid-fast bacilli and tests for viral antibodies were both negative. The microbiology study of the BAL with Giemsa and immunofluorescence staining, seven days after admission showed the existence of P. jiroveci in the lungs. Further, one day and five days after admission, (1-3) beta-D-glucan (BDG) levels were very high. The high serum level of BDG considerably decreased after treatment with trimethoprim-sulfamethoxazole (TMP-SMX) and the clinical condition of the patient increasingly improved.
    Le infezioni in medicina: rivista periodica di eziologia, epidemiologia, diagnostica, clinica e terapia delle patologie infettive 03/2014; 22(1):58-62.
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    ABSTRACT: Blastoschizomyces capitatus is a rare fungal pathogen that may lead to severe and fatal systemic infections especially in immunosuppressive individuals. B.capitatus strains have also been reported as the cause of hospital-acquired infections and outbreaks. In this report, three fungemia cases caused by B.capitatus with hematologic malignancies have been presented. The first case was a 20-year-old female with acute lymphoblastic leukemia, the second was a 26-year-old female with B-cell malignant lymphoma and the third was a 7-year-old male with B-cell acute lymphoblastic leukemia. All of the patients have been receiving chemotherapy, and treated with antibacterial and antifungal agents due to neutropenia. The blood cultures obtained from the second and third patients yielded B.capitatus although they were under empirical caspofungin therapy. Those patients have been treated with voriconazole and amphotericin B after the identification of B.capitatus, and clinical improvement were noted during their follow-up. However the first patient who was also under caspofungin therapy had died just before the isolation of B.capitatus from her blood culture. Conventional mycological methods [macroscopic and microscopic morphology, germ tube test, urea hydrolysis, carbohydrate assimilation tests (API 20C AUX; BioMerieux, France), growth temperature, cycloheximide sensitivity] were used for the identification of the isolates. The strains were identified as B.capitatus with the characteristics of annelloconidia formation, urease negativity, carbohydrate utilization, growth at 45°C and resistance to cycloheximide. Antifungal susceptibilities of isolates were determined by using microdilution method (for amphotericin B, fluconazole, itraconazole, voriconazole, ketoconazole) and E-test (for caspofungin). Minimum inhibitory concentration (MIC) values of the three B.capitatus strains were detected as 0.25, 0.125, 0.032 µg/ml for amphotericin B; 2, 2, 16 µg/ml for fluconazole; 0.064, 0.032, 0.032 µg/ml for itraconazole and 0.125, 0.064, 0.064 µg/ml for ketoconazole, respectively, while MIC values of all strains were 0.032 µg/ml for voriconazole and > 32 µg/ml for caspofungin. Since B.capitatus strains were isolated from the cases within about 15 days -sequentially-, the genotypes of the isolates were determined by repetitive sequence-based PCR (DiversiLab System; BioMerieux, France) to investigate the similarity rates. The results of analysis indicated 97% similarity between two (case 1 and 2) strains and 94.9% similarity in one strain (case 3) of B.capitatus, however the transmission route could not be clarified due to the absence of environmental sampling. In conclusion, B.capitatus should also be considered as a cause of systemic fungal infections in immunocompromised patients. Determination of the in vitro antifungal susceptibilities of clinical B.capitatus strains may contribute to the therapeutic approaches and epidemiological data.
    Mikrobiyoloji bülteni 10/2013; 47(4):734-41. · 0.61 Impact Factor
  • F Filiz Tekinşen, A Nedret Koç
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    ABSTRACT: Pneumocystis jirovecii causes pneumonia in premature, newborn or malnourished children, as well as in immunocompromised subjects such as chemotherapy receiving, transplant and AIDS patients. Since the mortality and morbidity rates of Pneumocystis pneumonia (PCP) in these patients were high, rapid and accurate diagnosis is important. The aim of this study was to evaluate the diagnostic value of Giemsa staining (GS), direct fluorescent antibody (DFA) assay, (1→3)-β-D-Glucan (BDG) test and real-time polymerase chain reaction (PCR) for the detection of P.jirovecii in clinical specimens. A total of 100 PCP-suspected patients with underlying diseases who were followed-up in outpatient and inpatient clinics of our hospital between December 2008-July 2010 were included in the study. All the patients (66 male, 34 female; mean age: 42.04 years) were under long-term immunosuppressive drug therapy due to their hematological malignancies, kidney transplantation, neutropenia or chronic diseases. Respiratory samples [86 bronchoalveolar lavage (BAL), 8 endotracheal aspirate, 1 nasotracheal aspirate, 3 pleural, 2 lung biopsy samples] obtained from the patients have been studied with GS (Merck, Germany), DFA (Pneumo Cel, Cellabs, Australia) and PCR (primers targeting MSG gene, LightCycler, Roche, USA), while serum samples (n= 100) with BDG (Fungitell, ACC Inc, USA) and PCR methods. In BAL samples two were found positive by GS, DFA and PCR, and six were positive only by PCR, yielding a total positivity in 8 (8%) samples. All of the sera were negative with PCR, however 29 of them were positive (> 80 pg/ml), five were equivocal (61-79 pg/ml) and 66 were negative (< 60 pg/ml) with BDG test. Eight patients with positive results in BAL-PCR were also positive with BDG test. Although the agreement between GS and DFA was high (κ= 1), it was observed as low between PCR and DFA (κ= 0.38), DFA and BDG (κ= 0.07), BAL-PCR and BDG (κ= 0.28). DFA taken as the gold standard, the sensitivity and specificity values of GS, PCR and BDG methods were calculated as 100% and 100%; 100% and 93%; 100% and 67%, respectively. In the ROC analysis performed for BDG test, with DFA and BAL-PCR taken as the gold standards, the sensitivity, specificity and cut-off values of BDG were estimated as 100%, 93.9% and 494 pg/ml, and 100%, 72.8% and 62 pg/ml, respectively. Our data indicated that, overall specificity was high (100%) when using GS and DFA tests together, while the sensitivity has been elevated to 93% with the additional use of PCR and BDG tests, in the diagnosis of PCP-suspected patients. In conclusion, combination of all these tests should be performed for the laboratory diagnosis of P.jirovecii.
    Mikrobiyoloji bülteni 10/2013; 47(4):658-67. · 0.61 Impact Factor
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    ABSTRACT: Background: To investigate the relationship between depression, nutritional status, and inflammatory markers in patients on peritoneal dialysis (PD). Patients and Methods: This prospective study included 40 PD patients and 20 healthy people. The severity of depressive symptoms was assessed using the Beck Depression Inventory, the Hamilton Depression Rating Scale, and the Hamilton Anxiety Rating Scale. The depressive patients received antidepressant drug for 8 weeks. Blood samples were taken before and after antidepressant treatment for the high-sensitive C-reactive protein (hs-CRP), interleukin (IL)-1, IL-6, and tumor necrosis factor-α (TNF-α) levels. Results: Ten (25%) of the 40 PD patients had depression. No significant difference was determined between depressive patients and nondepressive patients. The mean erythrocyte sedimentation rate was higher in depressive patients. There was no significant difference for other inflammation parameters, including hs-CRP, TNF-α, IL-1, and IL-6, between depressive patients and nondepressive patients. In the depressive patients, we did not observe any significant change in nutritional parameters after antidepressant treatment. When we evaluated inflammation parameters of the depressive patients before and after antidepressant treatment, only IL-1 and IL-6 levels were significantly increased after antidepressant treatment. Conclusion: The depressive disorder in PD patients is a common psychopathology and has no significant effects on nutritional status and inflammation.
    Renal Failure 11/2012; · 0.94 Impact Factor
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    ABSTRACT: Abstract The aim of this study was to assess the prevalence of denture-related stomatitis (DRS) in different attachment-retained overdenture wearers and its association with particular colonizing Candida species. Thirty-seven edentulous patients with implant-supported maxillary or mandibular overdentures were enrolled. A full clinical history was obtained, including details of their oral hygiene practices and the levels of erythema based on Newton's classification scale. Swabs were taken from the palate and investigated mycologically to identify the yeast colonies. Quantitative and qualitative microbiological assessments were performed, recording the total numbers of colonies (cfu), their color, and their morphological characteristics. Significant differences were found in cfu values from the attachment and inner surfaces of locator- and bar-retained overdentures (P < 0.05). Candida albicans was the most common species in both evaluations, being isolated from 81.3% of bar-retained overdentures and 38.1% of locator-retained overdentures. DRS developed in all patients using bar-retained overdentures, but in only 71.4% of those using locator-retained overdentures. No statistically significant relationship was found between bar and locator attachments according to smoking habit, overnight removal, or plaque and gingival indices (P > 0.05).
    Journal of Oral Implantology 09/2012; · 1.15 Impact Factor
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    ABSTRACT: Objective  In this study, we aimed to determine the prevalence of agents that cause superficial mycoses and clinical types of superficial mycoses in terms of age and gender in our region were aimed. Methods  Five hundred samples of nails, skin and skin with hair taken from 476 children and adult patients pre-diagnosed with superficial mycoses were examined by direct microscopy and cultural methods between October 2009 and October 2010. Results  Fungal elements were determined in 212 (42.4%) of the samples by using direct microscopy. Fungal growth was detected in 111 (22.2%) cultures of the same samples. It was found that the most common agents in superficial mycoses were Trichophyton rubrum (43.7%), Candida spp. (28%) and less often, Aspergillus spp., Malassezia spp., Saccharomyces spp., Rhodotorula spp., Trichosporon spp. and Trichophyton verrucosum. Conclusion  The significance of diagnosis by using direct microscopy and culturing together was again shown for the diagnosis of superficial fungal infections that follow a chronic course and affect the quality of life of patients. The most common agents in the superficial mycoses were T. rubrum. With this study, defining the aetiological agents of superficial mycoses in the Kayseri region is expected to contribute to the literature in terms of epidemiological data.
    Journal of the European Academy of Dermatology and Venereology 06/2012; · 2.69 Impact Factor
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    ABSTRACT: The aim of this study is to determine the clinical contribution of (1→3)-β-d-glucan (BDG) screening in the case of patients undergoing autologous haematopoietic stem-cell transplantation (HSCT). The records at our stem-cell transplantation centre were reviewed to identify the patients who underwent autologous HSCT between April 2009 and December 2010. Patients were classified as having proven invasive aspergillosis (IA), probable IA, or possible IA on the basis of the criteria established by the European Organization for Research and Treatment of Cancer and Mycoses Study Group (independent of the BDG results). During the study period, the patients were screened for BDG twice a week from transplant (day 0) until engraftment. Three patients were diagnosed with probable IA and five were diagnosed with possible IA. A total of 354 serum samples from79 patients who met the study inclusion criteria were used for statistical analysis. At the cut-off value of 80 pg ml(-1) , the sensitivity was 27.2% [95% confidence interval (CI); 7.3-60.6]; specificity, 94.4% (95% CI; 91.3-96.5); positive predictive value, 6.2%; and negative predictive, 93.7%. The clinical contribution of the BDG assay as a screening test was relatively limited in this cohort of patients undergoing autologous HSCT.
    Mycoses 04/2012; · 1.28 Impact Factor
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    ABSTRACT: To evaluate the presence of the relationship between depression and proinflammatory cytokine levels in hemodialysis (HD) patients. The study included 40 HD patients and 20 healthy controls. All participants were evaluated for the presence of depression using the structured clinical interview based on criteria defined by Diagnostic and statistical manual mental disorders (Fourth Edition, Text Revision) Axis I disorders. The severity of depressive symptoms was assessed using the Beck Depression Inventory, the Hamilton Depression Rating Scale, and the Hamilton Anxiety Rating Scale. The depressive patients received antidepressants for 8 weeks. Blood samples were taken at baseline and after 8 weeks of antidepressant treatment for interleukin-1 (IL-1), IL-6, and tumor necrosis factor-α (TNF-α) levels. A total of 9 (22.5%) of the 40 HD patients had depression. IL-1, IL-6, and TNF-α levels were significantly higher in HD patients compared with that in the control group, but were not significantly different between HD patients with and without depression. In the depressive patients, we observed no significant difference in proinflammatory cytokine levels after antidepressant treatment. The psychometric measurements in depressive patients decreased significantly after antidepressant treatment. We observed that depression is a common psychiatric disorder and has no significant effect on proinflammatory cytokine levels in HD patients; no important improvement in cytokine levels was observed after antidepressant therapy.
    Renal Failure 01/2012; 34(3):275-8. · 0.94 Impact Factor
  • Gokhan Metan, Ilkay Bozkurt, Ayse Nedret Koc
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    ABSTRACT: Respiratory infections are of particular concern in transplant patients. However, there is a significant overlap in the symptoms caused by different pathogens. Here, we report a case of Pneumocystis jiroveci pneumonia (PCP) in a renal transplant patient which was initially misdiagnosed as pandemic influenza H1N1. The patient did not improve under oseltamivir treatment and bronchoscopy was performed five days later after hospitalization. PCP was diagnosed by microscoping evaluation of bronchoalveolar lavage (BAL) fluid. Besides, BAL and serum of the patient yielded a large amount of 1,3-beta-D-glucan, a cellwall compotent of medically important mycoses including P. jiroveci. The patient was successfully treated with intravenous trimethoprim-sulfamethoxazole. Due to the lack of sensitivity of influenza case definitions, the attending physicians should be careful about alternative diagnoses particularly in transplant patients with severe respiratory infections.
    Le infezioni in medicina: rivista periodica di eziologia, epidemiologia, diagnostica, clinica e terapia delle patologie infettive 09/2011; 19(3):182-4.
  • Mycoses 01/2011; 54:80-81. · 1.28 Impact Factor
  • Mycoses 01/2011; 54:54. · 1.28 Impact Factor
  • Aslihan Cokuk, Ayse Nedret Koc, Altay Atalay
    Current Opinion in Biotechnology - CURR OPIN BIOTECHNOL. 01/2011; 22.
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    G Metan, C Ağkuş, H Buldu, A N Koç
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    ABSTRACT: The aim of this study was to investigate the interaction between intravenous piperacillin/tazobactam treatment and Aspergillus galactomannan antigen (GM) and 1,3-beta-D: -glucan (BDG) test results in patients without known risk factors for invasive fungal infections (IFI). Patients without known risk factors for IFI and who were to receive piperacillin/tazobactam monotherapy were considered eligible for the study. Serum samples were obtained both before and after antibiotic infusion on the first, third, seventh and tenth days of a piperacillin/tazobactam treatment course and 4 days after the last dose. GM was determined by Platelia Aspergillus ELISA (Bio-Rad Laboratories) and BDG was assayed using the Fungitell kit (Associates of Cape Cod, East Falmouth, MA) according to manufacturers' specifications. A total of 135 serum samples were collected from 15 patients. When a cut-off level of >or=0.7 was used for GM positivity, there were no false positive results. When a cut-off level of >or=0.5 was used, six serum samples were positive. There were no statistically significant differences between the median GM indices or median BDG levels of the various sampling times. However, 24 of 135 serum samples were positive for BDG for a threshold of 80 pg/mL. After ruling out fungal infections and all known potential causes of false BDG positivity, environmental contamination remained a possible cause of BDG reactivity. No significant interaction was observed between piperacillin/tazobactam administration and Aspergillus GM and BDG assays. Positive results for these tests should be evaluated cautiously in patients at high risk for IFI receiving piperacillin/tazobactam.
    Infection 03/2010; 38(3):217-21. · 2.44 Impact Factor
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    Mycoses 03/2010; 54(4):363-4. · 1.28 Impact Factor
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    The Veterinary record 08/2009; 165(2):57-8. · 1.80 Impact Factor
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    Peritoneal dialysis international: journal of the International Society for Peritoneal Dialysis 01/2009; 29(5):581-2. · 2.21 Impact Factor
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    ABSTRACT: The aim of the present study was to determine in vitro phospholipase and protease activities in 122 Candida spp. isolated from several anatomically distinct sites of healthy adults. C. albicans (66.4%) was the most frequently isolated Candida spp. C. glabrata (7.3%), C. tropicalis (6.3%) and C. kefyr (4.9%) were the most frequently isolated non-C. albicans Candida spp. Fifty (40.9%) of the isolates examined were phospholipase positive and 64 (52.4%) were protease positive. Forty-three (53.8%) of the C. albicans isolates tested were phospholipase producers--however, only a few strains of non-C. albicans Candida spp. behaved in the same way. Protease activity was detected in 46 (56.7%) of the C. albicans strains tested and in a few strains of non-C. albicans Candida spp. The levels of phospholipase and protease activities in commensal isolates were found to be lower than the levels of other enzyme activities previously reported in clinical Candida spp. isolates. The phospholipase activity of Candida spp. was found to be higher in oral (59.0%) and fecal (42.8%) isolates. The protease activity of Candida spp. was found to be higher in urogenital (55.1%) and skin (58.8%) isolates. We conclude that further investigations will be needed on the phospholipase and protease activity of Candida spp. in healthy subjects in order to clarify their contribution to fungal virulence.
    Japanese journal of infectious diseases 10/2007; 60(5):280-3. · 1.51 Impact Factor

Publication Stats

160 Citations
48.49 Total Impact Points

Institutions

  • 2005–2013
    • Erciyes Üniversitesi
      • • Department of Medical Microbiology
      • • Faculty of Medicine
      • • Department of Infectious Diseases and Clinical Microbiology
      • • Department of Animal Science
      Caesarea, Kayseri, Turkey