Yeast-like fungi as etiologic agents of blood infections in patients hospitalized in 1998-1999

The aim of the study was the analysis of frequency of yeast-like fungi as etiological agents of fungemias in patients hospitalized in operative and conservative wards of Medical Academy Central Clinical Hospital in Warsaw in 1998-1999. Peripheral blood samples and collected from vascular catheters were incubated in BacT/Alert system(Organon Teknika, USA). Positive blood samples were inoculated on Sabouraud medium with chloramphenicol (bioMerieux, France) (the time of cultivation from 48 h to 7 days at 30 C) and on chromogenic medium BBL CHROMagar Candida (Becton Dickinson, USA). Fungal strains were identified by standard mycological procedures using ID 32 C strips (ATB system, bioMerieux, France) and tests of Sanofi Diagnostics Pasteur (France). The total number of positive blood cultures was 1724. Fifty eight fungal strains were isolated from blood samples (3.36%). Strains belonged to 4 genera: Candida (55), Trichosporon (1), Saccharomyces (1) and Pichia (1). Thirty eight fungal strains were isolated from peripheral blood samples. Forty seven fungal strains were cultured from patients hospitalized in operative wards. Among fungi isolated from peripheral blood samples C. albicans (10), C. glabrata (9) and C. parapsilosis (5) strains dominated. From blood samples collected from vascular catheters most often C. albicans (7), C. glabrata (4) and C. parapsilosis (3) were isolated.     

Characterization of Candida Species from Different Populations in Taiwan

The opportunistic Candida species existing as part of commensal microbiota in humans are usually the etiological agents causing infections. We investigated whether isolates collected from different age groups, hospital units, and sources have distinct characteristics. A total of 913 isolates comprising 395 Candida albicans, 230 Candida tropicalis, 202 Candida glabrata, 62 Candida parapsilosis, 13 Candida krusei, and 11 of other six species were analyzed. Urine was the most common source (41.2%), followed by sputum (16.3%), blood (15.2%), and others (27.3%). Candida albicans and C. parapsilosis were more prevalent in the working group [from 19 to 65 years], whereas C. tropicalis and C. glabrata were more prevalent in the elder one (≥ 66 years). We found that the age of patients and the source of isolates affect the distribution of species. On the other hand, the drug susceptibility of isolates was associated with fungal species and whether patients were hospitalized.     

Species distribution, antifungal susceptibility and clonal relatedness of Candida isolates from patients in neonatal and pediatric intensive care units at a medical center in Turkey

The aim of this study was to assess species distribution, antifungal susceptibility and clonal relationships among Candida strains isolated from a group of pediatric/neonatal intensive care (PICU/NICU) patients that had a very high mortality rate (76%). The cases of 21 patients (19 with candidemia, 2 with Candida meningitides) treated over a 1-year period in a Turkish hospital PICU and NICU were retrospectively analyzed. Twenty-eight Candida isolates were detected from blood (20), cerebrospinal fluid (CSF) (2) and other specimens (6). Candida species were identified using the API ID 32C System. Susceptibility testing was done (all 28 isolates) for amphotericin B, fluconazole and itraconazole using the broth microdilution method. Arbitrarily primed polymerase chain reaction (AP-PCR) was used for molecular typing of the 3 most common ones; C. albicans (15), C. parapsilosis (6), and C. pelliculosa (4). Electrophoretic karyotyping (EK) was done to check clonal identity obtained by AP-PCR. Of the 20 blood isolates, 8 (40%) were C. albicans, 12 (60%) were non-albicans Candida, and one of the 2 CSF isolates was C. albicans. The overall species distribution was as follows: 15 C. albicans isolates, 6 C. parapsilosis isolates, 4 C. pelliculosa isolates, 2 C. famata isolates and 1 C tropicalis isolate. Amphotericin B had the best antifungal activity with a MIC90 of 0.125 microg/ml, and the rates of susceptibility to fluconazole and itraconazole were 93% and 82%, respectively. AP-PCR revealed 11 genotypes (4 were identical pairs, 7 were distinct) among the 15 C. albicans isolates, 2 genotypes (5 were classified in the same type) among the 6 C. parapsilosis isolates, and 4 separate genotypes for the 4 C. pelliculosa isolates. Karyotyping results correlated well with the AP-PCR findings. As indicated in the previous research, our results confirmed that non-albicans Candida species have become more frequently causative agents for invasive fungal infections in the ICU. Transmission of C. albicans and C. pelliculosa was relatively low, but transmission of C. parapsilosis was high, suggesting that more effective control and very strict treatment protocols are needed for patients having high mortality and invasive fungal infection in ICU.     

Slime production and proteinase activity of Candida species isolated from blood samples and the comparison of these activities with minimum inhibitory concentration values of antifungal agents

Slime and proteinase activity of 54 strains consisting of 19 Candida parapsilosis and 35 C. albicans strains isolated from blood samples were investigated in this study. Ketoconazole, amphothericin B, and fluconazole susceptibility of Candida species were compared with slime production and proteinase activity of these species. For both Candida species, no correlation was detected between the slime activity and minimum inhibitory concentration (MIC) values of the three antifungal agents. For both Candida species no correlation was detected between the proteinase activity and the MIC values of amphothericin B, and fluconazole however, statistically significant difference, was determined between the proteinase activity and MIC values of ketoconazole (p = 0.007). Slime production was determined by using modified Christensen macrotube method and proteinase activity was measured by the method of Staib. Antifungal susceptibility was determined through the guidelines of National Committee for Laboratory Standards (NCCLS M27-A).     

2013年中国侵袭性酵母菌感染流行病学和唑类药物耐药性分析

目的通过对中国侵袭性真菌监测网(CHIF-NET)2013年中国48家综合医院收集的1 562株酵母菌进行流行病学分布及唑类耐药性分析,为临床侵袭性酵母菌的唑类用药提供数据基础。方法收集2013年中国侵袭性真菌监测网48家医院共1 562株酵母菌菌株及其原始信息,采用基质辅助激光解析电离飞行时间质谱(MALDI-TO MS,法国生物梅里埃公司)结合核糖体DNA测序明确菌种鉴定;根据美国临床实验室标准化协会(CLSI)M44-A2纸片扩散法检测菌株对氟康唑及伏立康唑的敏感性。结果本研究共分离出酵母菌1 562株,其中白念珠菌分离率最高(38.4%),其次为近平滑念珠菌复合体(18.4%)、热带念珠菌(16.4%)、光滑念珠菌复合体(9.4%)及其他少见菌种(<6.4%);患者性别中男性占比(60.7%)高于女性(38.9%);患者年龄中,65岁以上年龄段患者最多(34.2%),其次为50~65岁(30.6%)、15~49岁(29.9%)和0~14岁患者(<1.9%);标本来源中以血液标本(46.4%)为主,其次为腹水(10.2%)、导管(9.2%)及引流液(8.5%)、分泌物(5.2%),其他标本类型均较少(<4.7%)。住院患者分离率(93%)显著高于门急诊患者(7%);科室类型中以外科患者(33.8%)为主,其次为重症监护病房(ICU)患者(27.5%)、内科患者(20.5%)及其他病房(<18.2%);药敏结果显示,白念珠菌及近平滑念珠菌复合体对氟康唑及伏立康唑敏感性均较高(>94%),热带念珠菌对氟康唑及伏立康交叉耐药率最高(21.9%),光滑念珠菌复合体交叉耐药率次之(15%),其次为季也蒙念珠菌(8.1%)和菌膜念珠菌(4.3%)。结论应持续加强中国地区侵袭性酵母菌监测,在使用抗菌药物过程中,合理控制其用量,防止耐药率的上升。     

血培养分离出212株念珠菌的菌种分布及耐药性分析

目的分析血培养分离出的念珠菌的菌种分布及耐药分析,为临床念珠菌血症的诊治提供理论依据。方法回顾性分析2017年1月—2020年12月期间,本院血培养分离出的念珠菌的菌种分布、药敏试验结果及患者血培养分离出念珠菌前后96 h内的G试验结果。结果血培养中分离出念珠菌314例,阳性率2.1%,其中非重复分离株212例。检出率最高的是近平滑念珠菌(72株,34.0%),其次是白念珠菌(55株,25.9%)和光滑念珠菌(28株,13.2%)。念珠菌检出率最高的科室为ICU(62株,29.2%),其次是新生儿科(39株,18.4%)和血液科(20株,9.4%)。检出的212株念珠菌除一株近平滑念珠菌为两性霉素B的非野生株,其余均为两性霉素B的野生株。白念珠菌对唑类药物的敏感率超过90%。但光滑念珠菌和热带念珠菌对唑类药物的敏感性较低。血培养分离出念珠菌的前后96 h内,G试验的阳性率为73.7%。结论本院念珠菌检出率前3位分别是近平滑念珠菌、白念珠菌和光滑念珠菌。光滑念珠菌、热带念珠菌对唑类药物敏感性比较低,在经验用药时需要合理选择抗真菌药物。G试验对念珠菌血症有较高的价值,需要对结果进行动态监测。     

Evaluation of a new chromogenic medium (Candida ID) for the isolation and presumptive identification of Candida albicans and other medically important yeasts

Candidiasis is a frequent human infection caused mainly by Candida albicans. However, other species are emerging as important pathogens, as Candida glabrata, Candida parapsilosis, Candida tropicalis, Candida krusei or Candida guilliermondii. Rapid identification of clinical isolates could facilitate diagnosis and treatment. Candida ID (bioMerieux, Spain) is a new medium for the isolation and presumptive identification of yeasts: C. albicans grows as blue colonies, and C. tropicalis, C. guilliermondii, Candida kefyr and Candida lusitaniae as pink ones. The utility of Candida ID was evaluated with more than 700 clinical isolates and type culture collection strains from different genera including Candida, Cryptococcus, Saccharomyces, and Rhodotorula. Presumptive identification was confirmed by germ tube test, microscopic morphology and chlamydoconidia production on corn meal agar and carbohydrate assimilation on API-ATB ID 32C or Vitek (bioMerieux). Growth on Candida ID was rapid (18-24 h) for most of the yeast strains tested. Sensitivity and specificity of identification of C. albicans was significantly high (>98%), since a very low number of isolates were found to be false negative or false positive. A better result was obtained for species growing as pink colonies (>99.5%). Detection of different species of medical important yeasts was easy with Candida ID, as perfectly distinct colors and textures of colonies were observed on this medium. Candida ID allowed the discrimination between C. glabrata (creamy and smooth) and C. krusei (rough and white) colonies. Other species showed different colony textures and colours, white being the predominant colour. Candida ID was very useful for the presumptive identification C. albicans isolates.     

Analysed yeast-like fungi isolated from blood of febrile neutropenic children with neoplastic disease

The aim of the study was the analysis of frequency of yeast-like fungi as etiological agents of fungemias in 181 children suffering from cancer treated in the years 1997-2000 in the Pediatric, Hematology and Oncology Clinique of the State Clinical Hospital in Bydgoszcz. Peripheral blood samples an collected from vascular catheters were incubated in VITAL 200 (bio Mérieux). Positive blood samples were inoculated on Sabouraud medium with chloramphenicol (bio Mérieux), of cultivation from 24 hours at 37 degrees C, following two hours at 22 degrees C. Fungal strains were identified by standard mycological procedures using ID 32 strips (bioMérieux). The total number of positive blood cultures was 1032 (22,1%). There have been recognized 22 fungemia by the children with fever in neutropenia period. Among fungi isolated from peripheral blood samples Candida spp. (13.4%), C. tropicalis (8.2%), stranis dominated. From blood samples collected from vascular catheters most often Candida spp. (29.9%), Candida parapsilosis (14.4%) and C. tropicalis (9.3%) were isolated.     

Identification of Candida albicans using the chromogenic medium Albicans ID

The correct identification of the microrganism is the base for epidemiological studies and treatment of infections. The aim of our study was to evaluate the efficacy of the chromogenic media Albicans ID (bioMerieux, France) in the identification of Candida albicans. A total of 190 yeasts strains were evaluated in the study. A rate of 100% of all C. albicans (80) and Candida dubliniensis (five) strains exhibited blue color. Nevertheless, the blue color was also observed with cultures of Candida rugosa (3/5) and Candida tropicalis (3/17). Albicans ID cromogenic media presented specificity rate of 90% and positive and negative predictive values of 88% and 100%, respectively, in the identification of C. albicans.     

Evaluation of fungaemia infections in a Hungarian university hospital between 1996 and 2009

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.     

Evaluation of blood cultures of children hospitalized in Upper Silesian Health Center of Child and Mother in Katowice

Blood cultures (1613) taken from children hospitalized in 13 wards of Upper Silesian Health Center of Child and Mother were studied using Bact/Alert 240 monitoring system (bioMerieux). Around 17.7% of studied cultures were positive: 285 microorganisms were isolated. Gram-positive cocci dominated: 32.3% were strains of MRCNS Gram-negative rods, mainlyEnterobacteriaceae were isolated in 18.6% of cases, non-fermenters--in 12.9%, yeasts (mainly C. albicans)--in 10.5%. More frequently blood cultures were positive in Intensive Care Unit (37.5%).     

Identification and antifungal susceptibility of Candida isolated from intensive care unit patients

Candida was isolated in 205 of 1060 clinical specimens (19.33%) in our laboratary sent from the intensive care unit for mycological investigation between January 98-December 99. All isolated strains were identified to species level using the API Candida system (Bio-Meieux, France) as follows; Candida albicans (n:115, 56.09%), Candida tropicalis (n:23, 11.21%), Candida parapsilosis (n:21, 10.24%), Candida glabrata (n:12, 5.83%). Candida kefyr (n:9, 4.39%), Candida lusitaniae (n:7, 3.41%), Candida famata (n:6, 2.92%), Candida krusei (n:6, 2.92%), Candida guilliermondii (n:6, 2.92%). These stains were identified using congo-red-glucose-brain-heart-infusion agar and slime production was determined in Candida albicans 53.91% and 67.77% in other than Candida species. In the present study, E test (AB Biodisk, Solna, Sweeden) was used to test antifungal susceptibility. The resistance to amphotericin B was 19.51%, to fluconazole 27.31% and to flucytosine 20.00%.     

Differences in extracellular enzymatic activity between Candida dubliniensis and Candida albicans isolates

Twenty-six Candida dubliniensis and 27 Candida albicans oral strains isolated from patients infected by the human immunodeficiency virus (HIV) were tested for germ tube production and 21 extracellular enzymatic activities. Assessment of the enzymatic profile was performed by using the API-ZYM commercial kit system (bioMerieux, France), which tests 19 different enzymes. Protease activity was expressed during the first days of incubation by 100% of the strains studied and resulted higher than phospholipase activity in the C. dubliniensis and C. albicans strains tested. The API-ZYM profile of the C. dubliniensis and C. albicans strains differs with respect to the number and percentage of the enzymes considered, as well as with the intensity of the substrate metabolized by the strains, in particular for the enzymes n 8 (cystine-arylamidase), n 12 (naphtol-AS-BI-phosphohydrolase) and n 16 (alpha-glucosidase). These enzymes may be useful to differentiate C. dubliniensis and C. albicans together with other phenotypic characteristics proposed in the literature. No relationship among protease, phospholipase and other extracellular enzymatic activities was observed in C. dubliniensis. The average percentage of strains filamentation after 4 h was between 32 and 42%.     

Candida parapsilosis complex water isolates from a haemodialysis unit: biofilm production and in vitro evaluation of the use of clinical antifungals

Candida parapsilosis, currently divided into three distinct species, proliferates in glucose-rich solutions and has been associated with infections resulting from the use of medical devices made of plastic, an environment common in dialysis centres. The aims of this study were (i) to screen for Candida orthopsilosis and Candida metapsilosis (100 environmental isolates previously identified as C. parapsilosis), (ii) to test the ability of these isolates to form biofilm and (iii) to investigate the in vitro susceptibility of Candida spp biofilms to the antifungal agents, fluconazole (FLC) and amphotericin B (AMB). Isolates were obtained from a hydraulic circuit collected from a haemodialysis unit. Based on molecular criteria, 47 strains were re-identified as C. orthopsilosis and 53 as C. parapsilosis. Analyses using a formazan salt reduction assay and total viable count, together with microscopy studies, revealed that 72 strains were able to form biofilm that was structurally similar, but with minor differences in morphology. A microtitre-based colorimetric assay used to test the susceptibility of fungal biofilms to AMB and FLC demonstrated that the C. parapsilosis complex displayed an increased resistance to these antifungal agents. The results from these analyses may provide a basis for implementing quality controls and monitoring to ensure the microbiological purity of dialysis water, including the presence of yeast.     

Activity of anidulafungin against Candida biofilms

Currently, no standardized method to study the in vitro activity of antifungal agents on biofilms is available, thus, the comparison among different authors is difficult. The studies discussed in this review use the XTT reduction to measure the activity of antifungals on biofilms of 24 h of maturation. To date, biofilm anidulafungin MICs of 47 isolates of Candida spp. (25 Candida albicans, 16 Candida tropicalis, 5 Candida dubliniensis and 1 Candida parapsilosis) have been published. The geometric mean MIC of anidulafungin on biofilms of Candida spp. is of 1.18 microg/ml. Against isolates of species with great capacity of biofilm formation, the geometric mean MIC is 0.325 (C. albicans), 2 (C. parapsilosis) and 0.5 microg/ml (C. dubliniensis). No echinocandin has activity on C. tropicalis biofilms. In addition, anidulafungin can be used for lock therapy of catheters since it is the echinocandin with the least in vitro paradoxical effect.     

Diabetes mellitus and candidiases

Patients in various clinical states of diabetes mellitus (according to the recommendation of the American Diabetes Association) as a primary diagnosis were examined for fungal infections by Candida species. Candida spp. were detected in urine, in the material taken from the mouth cavity, nails, skin lesions, ears and eyes, by cultivation on the Sabouraud agar, CHROMagar Candida, and by saccharide assimilation. In the group of diabetics with symptoms of oral candidiasis and denture stomatitis C. albicans was identified in 8 cases, C. tropicalis in 3, C. parapsilosis in 2; 1 strain of C. guilliermondii was also isolated. In patients with urinary tract infections the presence of C. albicans was shown in 12 cases; C. parapsilosis was detected in 6 cases and two strains of each C. tropicalis and C. krusei were also isolated. In patients with leg ulcers C. albicans (25 cases), C. parapsilosis (5), C. tropicalis (3) and one strain of each C. krusei and C. robusta were isolated. Otomycosis was associated with one strain of C. albicans, C. parapsilosis, C. tropicalis and C. guilliermondii. C. albicans was most frequently associated with onychomycosis, paronychia and endophthalmitis; C. parapsilosis was the second most rated yeast.     

In vitro antifungal susceptibility of clinical isolates of Candida spp. obtained from patients with different predisposing factors to candidosis

The increase in the number of infections caused by Candida species and the consequent use of antifungal agents favours an increase of resistant isolates. The aim of this study was to evaluate the antifungal susceptibility of Candida spp. isolates from patients with different systemic predisposing factors to candidosis. Seventy-nine Candida spp. isolates were assayed for in vitro susceptibility to amphotericin B, fluconazole, 5-flucytosine and itraconazole using the technique proposed by the Clinical and Laboratory Standards Institute (CLSI). Four C. albicans, one C. guilliermondii, four C. parapsilosis and two C. tropicalis isolates were resistant to amphotericin B. Only two isolate was resistant to itraconazole. All the isolates tested were susceptible to fluconazole and flucytosine. It could be concluded that the most efficient drugs against the Candida isolates studied were fluconazole and flucytosine and that all of the antifungal agents used in this study were effective against the Candida spp. isolates tested.     

Multicenter survey of in vitro antifungal resistance in yeasts of medical importance isolated from Spanish patients

Twelve Spanish laboratories collected 325 yeast clinical isolates during a 30 day's period, among them 224 Candida albicans, 30 Candida glabrata, and 27 Candida parapsilosis. In vitro antifungal susceptibility to amphotericin B, ketoconazole, fluconazole and itraconazole was determined by an agar diffusion test (Neo-Sensitabs, Rosco, Denmark). All the isolates tested were susceptible in vitroto amphotericin B and nearly all (97.2%) to itraconazole. In vitrosusceptibility to fluconazole and ketoconazole was high (90.2% and 91.4% of isolates, respectively) but showed variations depending on the species tested. Resistance to fluconazole and ketoconazole was low in C. albicans (4% and 3%, respectively), but 30% of Candida guilliermondii and 36% of C. glabrata isolates were resistant to fluconazole. Ketoconazole resistance was observed in 40% of C. glabrata, and 17% of Candida tropicalis. Resistance to antifungal drugs is very low in Spain and it is related to non-C. albicans isolates.     

Evaluation of Chromalbicans Agar for presumptive identification of Candida albicans

The utility of Chromalbicans Agar (Biolife Italiana, Milano, Italy) was evaluated with 723 clinical isolates and type culture collection strains from different genera including Candida, Cryptococcus, Pichia, Rhodotorula, Saccharomyces, Trichosporon y Zygosaccharomyces. Presumptive identification was confirmed by germ tube test and carbohydrate assimilation on API-ATB ID 32C (bioMerieux, France). Growth on Chromalbicans Agar was very useful for the presumptive identification of C. albicans isolates, and sensitivity and specificity values were significantly high (>97%), since a very low number of isolates were found to be false negative or false positive.     

Point prevalence, microbiology and antifungal susceptibility patterns of oral Candida isolates colonizing or infecting Mexican HIV/AIDS patients and healthy persons

We have conducted a longitudinal study over a 3-year period to address the point prevalence, microbiological characteristics and antifungal susceptibility patterns of yeast isolates colonizing or infecting the oral cavities of 111 HIV-infected (51 adults, 60 children) and 201 non HIV-infected (109 adults, 92 children) Mexican persons. Regarding the epidemiology of oral candidiasis, Candida albicans was the most frequent species isolated. Seventy-one out of 85 isolates from colonized persons were C. albicans (83.5%), 27 isolates of them were from HIV-infected children and 44 from non HIV-infected patients. Sixty-two isolates belonged to serotype A which was the most prevalent serotype of C. albicans. Non-albicans species (Candida glabrata, Candida tropicalis and Candida parapsilosis, and Saccharomyces cerevisiae) were isolated from 16.5% of colonized patients and from 38.5% patients with candidiasis or Candida-related lesions. There were nine episodes of infection or colonization by at least 2 different yeast species. In the case of HIV/AIDS patients, it was determined that yeast carriage was not associated with the number of CD4+ cells or the viral load, but HAART reduced the prevalence of oral candidiasis. Overall, most patients harbored strains in vitro susceptible to fluconazole, however 10.8% of the yeasts were resistant to one or more azole antifungal agents and 29% were intermediate susceptible to them. On the contrary, 5-fluorocytosine was very active against all isolates tested, and amphotericin B was active against 97.9% of them.