Species distribution and antifungal susceptibility of Candida bloodstream isolates in a tertiary medical center in Israel

Epidemiology, microbiology, clinical characteristics, and outcomes of candidemia in internal medicine wards-a retrospective study

BACKGROUND

The clinical characteristics of internal medicine ward (IMW) patients with candidemia are unclear. The aim of this study was to define the clinical characteristics of candidemic IMW patients and to study the incidence, species distribution, and outcomes of these patients compared to surgical and intensive care unit (ICU) candidemic patients.

METHODS

A retrospective cohort of candidemic patients in IMWs, general surgery wards, and an ICU at Beilinson Hospital during the period 2007-2014 was analyzed.

RESULTS

A total of 118 patients with candidemia were identified in six IMWs, two general surgery wards, and one ICU in the hospital. Candida albicans was the leading causative agent (41.1%). Higher proportions of Candida parapsilosis and Candida tropicalis isolates were observed in the IMW patients. IMW patients were significantly older, with poorer functional capacity, and had more frequently been exposed to antibiotic therapy within 90 days, in particular β-lactam-β-lactamase inhibitor combinations and cephalosporins. At onset of candidemia, a significantly lower number of IMW patients were mechanically ventilated (p<0.01); these patients did not have central line catheters comparable to ICU and surgical patients (p<0.001). They were less likely to receive adequate antifungal therapy within 48h, and this was the only significant predictor of survival in these patients (p=0.028): hazard ratio 3.7 (95% confidence interval 1.14-12.5) for therapy delayed to >48h.

CONCLUSIONS

IMW candidemic patients account for a substantial proportion of candidemia cases and have unique characteristics and high mortality rates.

Comparison of nosocomial candidemia of pediatric and adult cases in 2-years period at a Turkish university hospital

OBJECTIVE

Although there are limited numerous reports of candidemia in adults, data on paediatrics are stil limeted. The aim of the present study was to compare the aetiology and risk factors of nosocomial candidemia among the paediatric and adults in our hospital.

MATERIALS AND METHODS

This study includes the patients hospitalised and diagnosed as fungemia at Ondokuz Mayis University Hospital between June 30, 2007 and June 30, 2009 whose blood cultures sent to our microbiology laboratory. After fungal growth was observed in blood cultures, the yeast cells were inoculated onto Saboraud glucose agar. The colonies were identified by conventional yeast identification methods and ID 32C yeast identification system according to the manifacturer's instructions.

RESULTS

During this period 51 paediatric and 69 adults were studied. The most common yeast form was Candida albicans (43.3%) followed by C. parapsilosis (25.0%) and C. tropicalis (17.5%). Although the non-albicans Candida species represent more than half (56.7%) of all candidemic cases C. albicans was the most common frequent etiologic agent. There was no statistically significant difference between patient age (paediatric and adult) and distribution of Candida species (p>0.05) Neoplasia (in adults) and prematurity (in paediatrics) were the main underlying diseases. Predisposing factors and mortality rates were not different among paediatrics and adults.

CONCLUSION

We reinforce the necessity of continous epidomiologic surveillance to follow the dynamics of candidemia.

Evaluation of antifungal susceptibility testing with microdilution and Etest methods of Candida blood isolates

Candida species that show an increasing number of clinical and/or microbiological resistance to several antifungals and are the most common agents of invasive fungal infections. The aim of this study was to investigate the in vitro susceptibility of Candida blood isolates to antifungal agents (amphotericin B, fluconazole, itraconazole, and voriconazole) by comparative use of the CLSI reference microdilution method and Etest. Four hundred Candida blood isolates (215 Candida albicans, 185 non-albicans Candida strains) were included in the study. The broth microdilution test was performed according to the CLSI M27 A2 document. Etest was carried out according to the manufacturer's instructions. The MIC results obtained with reference microdilution were compared with those obtained with the Etest by using percent and categorical agreements. According to MIK(90) values, voriconazole was the most active and itraconazole was the least active drug in vitro against all Candida species. Other than voriconazole, statistically significant differences were found when the susceptibility of Candida albicans and non-albicans Candida spp. to amphotericin B, fluconazole, and itraconazole were compared. These antifungal agents were found to be more active to C. albicans. Among the non-albicans Candida species, the lowest MIC values were obtained for Candida parapsilosis isolates. When the standard method was compared with Etest, the total agreement was higher for C. albicans than for non-albicans species, especially for fluconazole and voriconazole. In view of the findings, it was concluded that itraconazole showed the lowest activity against all Candida species. Etest could be an alternative method in assessing the in vitro antifungal susceptibility of Candida spp., but it is more convenient to use the microdilution method for studying in vitro susceptibility of non-albicans species, in particular for those possessing high MIC values against azoles.

Direct fluconazole susceptibility testing of positive Candida blood cultures by flow cytometry

The standard methods for yeast susceptibility testing require 24-48 h of incubation. As there has been an increase in incidence of non-albicans Candida species, the clinician is very often wary of initiating therapy with fluconazole until a final susceptibility report is generated, especially when treating very sick patients. A rapid reliable susceptibility testing method would enable the clinician to prescribe fluconazole, thus avoiding more toxic or expensive therapy. To determine the feasibility of direct susceptibility testing of Candida species to fluconazole by a rapid flow cytometric method, 50 Candida strains were seeded into blood culture bottles and were tested for susceptibility to fluconazole directly from the bottles after their being flagged as positive by the blood culture instrument. Minimal inhibitory concentration (MIC) determined by fluorescent flow cytometry (FACS) showed excellent agreement to that determined by macrodilution. Following the seeding experiments, 30 true patient specimens were tested directly from positive blood cultures, and MIC determined by both methods showed excellent agreement. Antifungal susceptibility testing by FACS directly from positive blood culture bottles is a reliable, rapid method for susceptibility testing of Candida to fluconazole. The method allows same-day results, does not require subculture to agar media, and can greatly assist in the selection of appropriate antifungal therapy.

Candida glabrata fungaemia in intensive care units

Candidaemia is increasingly important in intensive care units (ICUs). Compared with Candida albicans fungaemia, the impact of C. glabrata fungaemia on ICU patients is not well-known. The aim of this study was to investigate the clinical features, the antifungal susceptibility and the treatment outcomes of C. glabrata fungaemia in ICU patients. The medical records of ICU patients with candidaemia between 2000 and 2005 were reviewed retrospectively, and antifungal susceptibility testing was performed for isolates of C. glabrata. Among 147 episodes of candidaemia occurring in adult ICUs, C. glabrata was the second most common species and accounted for 45 (30%) episodes of candidaemia. The incidence of C. glabrata fungaemia was 1.3/1000 ICU admissions. Fluconazole resistance was found in 11% of C. glabrata isolates. The 30-day all-cause mortality rate was 58%. Therapeutic regimens containing amphotericin B were associated with better outcome. Despite higher fluconazole resistance, C. glabrata candidaemia was not associated with greater mortality than non-glabrata candidaemia in the ICU setting.

Species distribution and susceptibility to azole antifungals of Candida bloodstream isolates from eight university hospitals in Korea

PURPOSE

The incidence of Candida bloodstream infections (BSI) has increased over the past two decades. The rank order of occurrence and the susceptibility to antifungals of the various Candida species causing BSI are important factors driving the establishment of empirical treatment protocols; however, very limited multi-institutional data are available on Candida bloodstream isolates in Korea.

MATERIALS AND METHODS

We investigated the susceptibility to azole antifungals and species distribution of 143 Candida bloodstream isolates recovered from eight university hospitals over a six-month period. Minimal inhibitory concentrations (MICs) of fluconazole, itraconazole, and voriconazole for each isolate were determined by the broth microdilution method of the Clinical and Laboratory Standards Institute (CLSI).

RESULTS

The Candida species recovered most frequently from the blood cultures was C. albicans (49%), followed by C. parapsilosis (22%), C. tropicalis (14%), and C. glabrata (11%). The MIC ranges for the Candida isolates were 0.125 to 64 microg/mL for fluconazole, 0.03 to 2 microg/mL for itraconazole, and 0.03 to 1 microg/mL for voriconazole. Overall, resistance to fluconazole was found in only 2% of the Candida isolates (3/143), while the dose-dependent susceptibility was found in 6% (8/143). The resistance and dose-dependent susceptibility of itraconazole were found in 4% (6/143) and 14% (20/143) of the isolates, respectively. All bloodstream isolates were susceptible to voriconazole (MIC, < or = 1 microg/mL).

CONCLUSION

Our findings show that C. albicans is the most common cause of Candida-related BSI, followed by C. parapsilosis, and that the rates of resistance to azole antifungals are still low among bloodstream isolates in Korea.

Species distribution and antifungal susceptibility patterns of Candida spp. bloodstream isolates from a Brazilian tertiary care hospital

In this work, we collect data from surveys of bloodstream Candida isolates performed in Brazil from 1996 to 2004. Besides, we analyzed the species distribution of bloodstream Candida isolates together with potential risk factors for candidemia and the susceptibility profile of these isolates in patients from Hospital das Clínicas in Goiânia city, Brazil. Blood samples were collected in the admission day and on every 7 days, in the intensive care unit (ICU) of a tertiary hospital. Candida isolates were identified by standard protocols that included germ tube formation, chlamydoconidia production on cornmeal agar and sugar fermentation and assimilation tests. Data of patients were recorded and analyzed according to age at the time of diagnosis, gender and presence of potential risk factors. Statistical analysis was used to determine if the time of hospital permanence increased Candida colonization in ICU patients' blood. The antifungal susceptibility testing was performed by broth microdilution method according to document NCCLS/CLSI M27-A2. Among the 345 blood samples cultured, candidemia was recovered in 33 patients, which were isolated 51.5% of Candida non-albicans. Fungemia was associated with long-term hospitalization. Fluconazole, itraconzole, voriconazole and amphotericin B exhibited a potent activity against all isolates of Candida. Voriconazole MICs were much low for all isolates tested. This work confirms data of increase of Candida non-albicans species in bloodstream in ICU and shows that voriconazole in vitro activity was higher than those of itraconazole, fluconazole and amphotericin B.

Endogenous Candida endophthalmitis

Intraocular Candida infections, although uncommon, represent an important clinical problem owing to the potential for visual loss, which can be bilateral. Candida chorioretinitis and endophthalmitis are complications of systemic candidiasis with extension of the fungal pathogens to the uvea and retina. Early diagnosis and prompt management significantly affect the visual prognosis for these patients. This review evaluates the current literature on Candida endophthalmitis and includes discussion on presentation, diagnosis and management strategies. New systemic and intravitreal antifungal agents are also reviewed in the context of the management of intraocular fungal infection.