Active surveillance for candidemia, Australia

Consensus guidelines for the treatment of yeast infections in the haematology, oncology and intensive care setting, 2014

Pathogenic yeast forms are commonly associated with invasive fungal disease in the immunocompromised host, including patients with haematological malignancies and patients of haemopoietic stem cell transplants. Yeasts include the Candida spp., Cryptococcus spp., Pneumocystis jirovecii and some lesser-known pathogens. Candida species remain the most common cause of invasive yeast infections (and the most common human pathogenic fungi). These guidelines present evidence-based recommendations for the antifungal management of established, invasive yeast infections in adult and paediatric patients in the haematology/oncology setting. Consideration is also given to the critically ill patient in intensive care units, including the neonatal intensive care unit. Evidence for 'pre-emptive' or 'diagnostic-driven antifungal therapy' is also discussed. For the purposes of this paper, invasive yeast diseases are categorised under the headings of invasive candidiasis, cryptococcosis and uncommon yeast infections. Specific recommendations for the management of Pneumocystis jirovecii are presented in an accompanying article (see consensus guidelines by Cooley et al. appearing elsewhere in this supplement).

Candida species epidemiology 2000-2013: a laboratory-based report

OBJECTIVE

To describe a prospective laboratory-based surveillance of Candida species that were collected from different anatomical sites of patients admitted to the University of Malaya Medical Centre, Malaysia, from the year 2000 to 2013.

METHODS

Conventional (culture, microscopic examination and carbohydrate assimilation test) and molecular (PCR amplification and DNA sequencing) techniques were used to identify Candida species.

RESULTS

A total of 16 Candida species isolated from 34 392 clinical samples were from the oral cavity (oral swabs and throat swabs), blood, respiratory tract (sputum, tracheal secretions, nasopharyngeal aspirates, bronchoalveolar lavage), high vaginal swab, pus and urine. C. albicans (66.70%, 22 941/34 392), C. glabrata (11.71%, 4029/34 392), C. parapsilopsis (10.74%, 3692/34 392), C. tropicalis (9.19%, 3162/34 392) and C. krusei (1.15%, 396/34 392) were the five predominant Candida species. C. albicans was the predominant species isolated from the oral cavity, respiratory tract and high vaginal swab; while the Candida species isolated from blood, urine and pus were predominant non-albicans Candida. Uncommon Candida species, such as C. lusitaniae, C. haemulonii, C. humicola, Pichia ohmeri and C. ciferrii, were also isolated in this study.

CONCLUSION

Our study expands the current knowledge of the epidemiology of non-invasive and invasive candidiasis in Malaysia. The variability of the Candida species distribution from different anatomical sites highlights the significance of local epidemiology in disease management and selection of antifungal agents.

Incidence and species distribution of candidaemia in Asia: a laboratory-based surveillance study

The epidemiology of candidaemia varies between hospitals and geographic regions. Although there are many studies from Asia, a large-scale cross-sectional study across Asia has not been performed. We conducted a 12-month, laboratory-based surveillance of candidaemia at 25 hospitals from China, Hong Kong, India, Singapore, Taiwan and Thailand. The incidence and species distribution of candidaemia were determined. There were 1601 episodes of candidaemia among 1.2 million discharges. The overall incidence was 1.22 episodes per 1000 discharges and varied among the hospitals (range 0.16-4.53 per 1000 discharges) and countries (range 0.25-2.93 per 1000 discharges). The number of Candida blood isolates and the total number of fungal isolates were highly correlated among the six countries (R² = 0.87) and 25 hospitals (R² = 0.77). There was a moderate correlation between incidence of candidaemia and the intensive care unit (ICU)/total bed ratio (R² = 0.47), although ICUs contributed to only 23% of candidaemia cases. Of 1910 blood isolates evaluated, Candida albicans was most frequently isolated (41.3%), followed by Candida tropicalis (25.4%), Candida glabrata (13.9%) and Candida parapsilosis (12.1%). The proportion of C. tropicalis among blood isolates was higher in haemato-oncology wards than others wards (33.7% versus 24.5%, p 0.0058) and was more likely to be isolated from tropical countries than other Asian countries (46.2% versus 18.9%, p 0.04). In conclusion, the ICU settings contribute, at least in part, to the incidence variation among hospitals. The species distribution is different from Western countries. Both geographic and healthcare factors contribute to the variation of species distribution.

Surveillance of antifungal susceptibilities in clinical isolates of Candida species at 36 hospitals in China from 2009 to 2013

BACKGROUND

The purpose of this study was to determine the species distribution and to monitor the antifungal susceptibility profiles of clinical Candida isolates collected in China from 2009 to 2013.

METHODS

The antifungal susceptibilities of 952 Candida isolates were tested.

RESULTS

Candida albicans was the most common species, accounting for 65.7% of the total isolates. The most frequently isolated non-albicans Candida species in this study was Candida glabrata (193, 20.3%). Nearly 7.6%, 3.2%, 1.8%, and 1.1% of the 952 isolates exhibited decreased susceptibility to fluconazole, voriconazole, itraconazole, and flucytosine, respectively. Moreover, seven C. albicans and one Candida krusei had an amphotericin B minimum inhibitory concentration (MIC) of 2 μg/ml.

CONCLUSIONS

The distribution of species and the prevalence of antifungal resistance in Candida isolates varied among different areas in China. Continuous monitoring of resistance patterns is necessary to control the spread of resistance in clinical isolates of Candida species.

Incidence, characteristics and outcome of ICU-acquired candidemia in India

PURPOSE

A systematic epidemiological study on intensive care unit (ICU)-acquired candidemia across India.

METHOD

A prospective, nationwide, multicentric, observational study was conducted at 27 Indian ICUs. Consecutive patients who acquired candidemia after ICU admission were enrolled during April 2011 through September 2012. Clinical and laboratory variables of these patients were recorded. The present study is an analysis of data specific for adult patients.

RESULTS

Among 1,400 ICU-acquired candidemia cases (overall incidence of 6.51 cases/1,000 ICU admission), 65.2 % were adult. Though the study confirmed the already known risk factors for candidemia, the acquisition occurred early after admission to ICU (median 8 days; interquartile range 4-15 days), even infecting patients with lower APACHE II score at admission (median 17.0; mean ± SD 17.2 ± 5.9; interquartile range 14-20). The important finding of the study was the vast spectrum of agents (31 Candida species) causing candidemia and a high rate of isolation of Candida tropicalis (41.6 %). Azole and multidrug resistance were seen in 11.8 and 1.9 % of isolates. Public sector hospitals reported a significantly higher presence of the relatively resistant C. auris (8.2 vs. 3.9 %; p = 0.008) and C. rugosa (5.6 vs. 1.5 %; p = 0.001). The 30-day crude and attributable mortality rates of candidemia patients were 44.7 and 19.6 %, respectively. Logistic regression analysis revealed significant independent predictors of mortality including admission to public sector hospital, APACHE II score at admission, underlying renal failure, central venous catheterization and steroid therapy.

CONCLUSION

The study highlighted a high burden of candidemia in Indian ICUs, early onset after ICU admission, higher risk despite less severe physiology score at admission and a vast spectrum of agents causing the disease with predominance of C. tropicalis.

Antifungal susceptibilities of Candida glabrata species complex, Candida krusei, Candida parapsilosis species complex and Candida tropicalis causing invasive candidiasis in China: 3 year national surveillance

OBJECTIVES

To define the antifungal susceptibility patterns of the most common non-albicans Candida spp. in China.

METHODS

We evaluated the susceptibilities to nine antifungal drugs of Candida parapsilosis species complex, Candida tropicalis, Candida glabrata species complex and Candida krusei isolates from patients with invasive candidiasis at 11 hospitals over 3 years. Isolates were identified by MALDI-TOF MS supplemented by DNA sequencing. MICs were determined by Sensititre YeastOne(TM) using current clinical breakpoints/epidemiological cut-off values to assign susceptibility (or WT), and by CLSI M44-A2 disc diffusion for fluconazole and voriconazole.

RESULTS

Of 1072 isolates, 392 (36.6%) were C. parapsilosis species complex. C. tropicalis, C. glabrata species complex and C. krusei comprised 35.4%, 24.3% and 3.7% of the isolates, respectively. Over 99.3% of the isolates were of WT phenotype to amphotericin B and 5-flucytosine. Susceptibility/WT rates to azoles among C. parapsilosis species complex were ≥97.5%. However, 11.6% and 9.5% of C. tropicalis isolates were non-susceptible to fluconazole and voriconazole, respectively (7.1% were resistant to both). Approximately 14.3% of C. glabrata sensu stricto isolates (n = 258) were fluconazole resistant, and 11.6% of C. glabrata sensu stricto isolates were cross-resistant to fluconazole and voriconazole. All C. krusei isolates were susceptible/WT to voriconazole, posaconazole and itraconazole. Overall, 97.7%-100% of isolates were susceptible to caspofungin, micafungin and anidulafungin, but 2.3% of C. glabrata were non-susceptible to anidulafungin. There was no azole/echinocandin co-resistance. Disc diffusion and Sensititre YeastOne(TM) methods showed >95% categorical agreement for fluconazole and voriconazole.

CONCLUSIONS

In summary, reduced azole susceptibility was seen among C. tropicalis. Resistance to echinocandins was uncommon.

Variation in proanthocyanidin content and composition among commonly grown North American cranberry cultivars (Vaccinium macrocarpon)

BACKGROUND

Cranberry fruit (Vaccinium macrocarpon) is rich in polyphenols, particularly oligomeric proanthocyanidins (PACs) possessing antimicrobial and antioxidant properties. PACs may play a role in resistance to fruit rot. Although many cranberry cultivars are grown for use in foods, beverages and nutraceuticals, data on PAC content among cultivars is limited. Eight cultivars were sampled from four growing regions during the 2010 season and analyzed for PAC content and composition.

RESULTS

MALDI-TOF MS showed that isolated PACs had similar oligomer profiles among cultivars. The major constituents were A-type (epi)catechin oligomers of two to eight degrees of polymerization. Total PAC content ranged between 18 and 92 g PAC kg⁻¹ dried fruit, quantified as procyanidin A2 by the dimethylaminocinnamaldehyde method. Among the cultivars sampled, Howes had the highest total PACs (76-92 g kg⁻¹), followed by Mullica Queen and Early Black (48-82 g kg⁻¹). Ben Lear, a disease-susceptible variety, was significantly lower in PACs than the other cultivars (P < 0.001).

CONCLUSIONS

Several traditional and newer cultivars of cranberry from various growing regions in North America are excellent sources of PACs, particularly the Howes, Mullica Queen and Early Black cultivars. PAC content may play a role in keeping quality.

Support for the EUCAST and revised CLSI fluconazole clinical breakpoints by Sensititre® YeastOne® for Candida albicans: a prospective observational cohort study

OBJECTIVES

Species-specific clinical breakpoints (CBPs) for Candida spp. were established following consideration of clinical outcomes in patients with oesophageal candidiasis. We sought to further determine the validity of the current CBPs based on data from a prospective candidaemia study.

PATIENTS AND METHODS

All Candida albicans candidaemia episodes in patients enrolled in the Australian Candidaemia Study and who were treated with fluconazole monotherapy were included. Fluconazole MICs were established using Sensititre(®) YeastOne(®).

RESULTS

Two hundred and seventeen evaluable episodes were identified, 93.5% of which occurred in adult patients. Fluconazole was commenced within 72 h of blood culture positivity in 96.3% (209/217) of episodes. Fluconazole doses were appropriate in 89.9% (195/217) of episodes and the median duration of therapy was 14 days (IQR 8-21 days) for the whole cohort. The all-cause 30 day mortality was 19.8% (43/217), with 37.2% (16/43) of deaths attributed to candidaemia. Classification and regression tree (CART) analysis identified a fluconazole MIC target of ≥2 mg/L for infection-related mortality and ≥4 mg/L for overall 30 day mortality. Overall mortality was no different in episodes with isolates above or below the identified MIC target, although there was a trend towards significance (P = 0.051). On univariate analysis, infection-related mortality was significantly increased in C. albicans episodes with an MIC ≥2 mg/L compared with those below this MIC target (20.6% versus 4.9%; P = 0.001). This target remained an independent predictor of infection-related mortality (OR 8.2; 95% CI 2.3-29.7; P = 0.001).

CONCLUSIONS

We observed a direct relationship between infection-related mortality and rising fluconazole MIC for C. albicans candidaemia; overall, the data support the EUCAST and revised CLSI fluconazole clinical breakpoints.

Epidemiology and risk factors for invasive candidiasis

The number of immunosuppressive patients has increased significantly in recent years. These patients are at risk for opportunistic infections, especially fungal infections. Candidiasis is one of the most frequent fungal infections determined in these immunosuppressive patients and its epidemiology has changed over the last two decades. Recently, new antifungal agents and new therapy strategies such as antifungal prophylaxis, secondary prophylaxis, and preemptive therapy have come into use. These changes resulted in the alteration of Candida species causing invasive infections. The incidence of Candida albicans was decreased in many countries, especially among patients with immunosuppressive disorders, while the incidence of species other than C. albicans was increased. In this review, incidence, risk factors, and species distribution of invasive candidiasis are discussed.

Anidulafungin: advantage for the newcomer?

Anidulafungin is the most recently approved compound of the echinocandin antifungal class. Its mode of action is the noncompetitive inhibition of β-(1,3)-D-glucan synthesis. Potent fungicidal activity has been demonstrated against many Candida spp., including non-albicansCandida spp. and fluconazole-resistant strains, as well as fungistatic activity against Aspergillus spp. Owing to low oral bioavailability, it can only be administered intravenously. Anidulafungin is not metabolized by the liver and renal clearance is negligible, thus rendering dosage adjustments in patients with impaired hepatic or renal function unnecessary. Due to lack of interference with the cytochrome P450 pathway, it displays minimal drug-drug interaction. Anidulafungin has been approved by the US FDA for the treatment of esophageal and invasive candidiasis after clinical trials demonstrated its noninferiority to fluconazole. In September 2007, anidulafungin gained EMEA approval for the treatment of invasive candidiasis in adult non-neutropenic patients. For those with invasive or noninvasive candidiasis with resistance or intolerance to fluconazole in particular, as well as those requiring antifungal medication, that anidulafungin does not interact with concomitant medication means it may be regarded as a safe and efficacious treatment option. Promising results from animal models and experience with the other echinocandins indicate several potential lines of investigation: invasive aspergillosis, prophylaxis and treatment of transplant patients, and empirical treatment in patients with febrile neutropenia. Significant differences in clinical efficacy or safety favoring anidulafungin over the other echinocandins are yet to be discovered.

Candida identification: a journey from conventional to molecular methods in medical mycology

The incidence of Candida infections have increased substantially in recent years due to aggressive use of immunosuppressants among patients. Use of broad-spectrum antibiotics and intravascular catheters in the intensive care unit have also attributed with high risks of candidiasis among immunocompromised patients. Among Candida species, C. albicans accounts for the majority of superficial and systemic infections, usually associated with high morbidity and mortality often caused due to increase in antimicrobial resistance and restricted number of antifungal drugs. Therefore, early detection of candidemia and correct identification of Candida species are indispensable pre-requisites for appropriate therapeutic intervention. Since blood culture based methods lack sensitivity, and species-specific identification by conventional method is time-consuming and often leads to misdiagnosis within closely related species, hence, molecular methods may provide alternative for accurate and rapid identification of Candida species. Although, several molecular approaches have been developed for accurate identification of Candida species but the internal transcribed spacer 1 and 2 (ITS1 and ITS2) regions of the rRNA gene are being used extensively in a variety of formats. Of note, ITS sequencing and PCR-RFLP analysis of ITS region seems to be promising as a rapid, easy, and cost-effective method for identification of Candida species. Here, we review a number of existing techniques ranging from conventional to molecular approaches currently in use for the identification of Candida species. Further, advantages and limitations of these methods are also discussed with respect to their discriminatory power, reproducibility, and ease of performance.

Epidemiology of candidaemia and invasive candidiasis. A changing face

Invasive candidiasis is a leading cause of mortality. Candidaemia is the most common clinical presentation of invasive candidiasis but more that 30% of these infections do not yield positive blood cultures. Candida albicans remains the predominant aetiology, accounting for 50% of all cases. However, there has been an epidemiological shift in the last decades. Some species of Candida different to C. albicans have emerged as an important cause of severe candidaemia as they can exhibit resistance to fluconazole and other antifungal agents. Moreover, there is a different distribution of non C. albicans Candida species in relationship to patients' and hospital characteristics. Thus, Candida parapsilosis has been associated to candidaemia in neonates and young adults. This species usually has an exogenously origin and contaminates medical devices, causing central venous catheter-associated candidaemias. Candida glabrata, Candida tropicalis and Candida krusei are isolated in blood cultures from older patients (>65 years) with important risk factors, such as major abdominal surgery, solid tumours and haematologic malignancies, transplants, and/or prolonged treatment with corticoids. Moreover, important geographical differences in the distribution of the Candida species different to C. albicans causing invasive candidiasis have been reported: C. parapsilosis predominates in Australia, Latin America and Mediterranean countries of Africa, Asia and Europe. In contrast, C. glabrata has an important aetiological role in USA and Central and Northern Europe. Finally, an important and worrying issue is that mortality due to invasive candidiasis remains unacceptably high. This manuscript is part of the series of works presented at the "V International Workshop: Molecular genetic approaches to the study of human pathogenic fungi" (Oaxaca, Mexico, 2012).

Distribution and drug susceptibilities of Candida species causing candidemia from a medical center in central Taiwan

Invasive fungal infections have increased significantly in the past few decades because of the increase in high-risk populations. To investigate the distribution and drug susceptibilities of such infections, we analyzed all 152 Candida isolates causing candidemia from 2004 to 2006 at the China Medical University Hospital, a medical center in central Taiwan. Candida albicans was the most common species, accounting for 52.6% of the isolates, followed by C. tropicalis (19.7%), C. parapsilosis (14.5%), C. glabrata (8.6%), C. guilliermondii (3.9%), and C. pelliculosa (0.7%). All isolates were susceptible to amphotericin B, anidulafungin, micafungin, and voriconazole according to minimum inhibitory concentrations (MICs) after a 24-h incubation; 0.7%, 6.6%, and 7.9% of isolates were resistant to amphotericin B, fluconazole, and voriconazole, respectively, after 48-h incubation. Both C. albicans and C. parapsilosis had high degrees of agreement for azoles between 24- and 48-h incubation periods, whereas C. glabrata (38.5-46.2%) and C. tropicalis (56.7-63.3%) did not. The majority of the isolates with high azole MICs displayed a trailing growth phenotype. Hence, the MICs of different drugs after 24-h incubation may be considered for prognosis of candidemia.

Species distribution and drug susceptibilities of Candida isolates in TSARY 2010

Susceptibilities to antifungal drugs of 1083 Candida isolates collected in Taiwan Surveillance of Antimicrobial Resistance of Yeasts in 2010 were determined. There were 422 (39%) C. albicans, 270 (24.9%) C. tropicalis, 258 (23.8%) C. glabrata, 87 (8%) C. parapsilosis, 18 (1.7%) C. krusei, and 28 (2.6%) of 13 other species. In the present study, we have applied species-specific clinical breakpoints for common species and epidemiological cutoff values for rare species. We found that majority of isolates were susceptible to tested drugs. A total of 15, 3, 2, and 0 isolates were not susceptible to fluconazole, voriconazole, amphotericin B, and anidulafungin, respectively. We found that three of the four fluconazole non-susceptible C. albicans isolates were resistant to voriconazole. Hence, there is an issue of cross-resistance among azole-type drugs.

Invasive fungal infections in acute leukemia

Invasive fungal infection (IFI) is among the leading causes for morbidity, mortality, and economic burden for patients with acute leukemia. In the past few decades, the incidence of IFI has increased dramatically. The certainty of diagnosis of IFI is based on host factors, clinical evidence, and microbiological examination. Advancement in molecular diagnostic modalities (e.g. non-culture-based serum biomarkers such as β-glucan or galactomannan assays) and high-resolution radiological imaging has improved our diagnostic approach. The early use of these diagnostic tests assists in the early initiation of preemptive therapy. Nonetheless, the complexity of IFI in patients with leukemia and the limitations of these diagnostic tools still mandate astute clinical acumen. Its management has been further complicated by the increasing frequency of infection by non-Aspergillus molds (e.g. zygomycosis) and the emergence of drug-resistant fungal pathogens. In addition, even though the antifungal armamentarium has expanded rapidly in the past few decades, the associated mortality remains high. The decision to initiate antifungal treatment and the choice of anti-fungal therapy requires careful consideration of several factors (e.g. risk stratification, local fungal epidemiologic patterns, concomitant comorbidities, drug-drug interactions, prior history of antifungal use, overall cost, and the pharmacologic profile of the antifungal agents). In order to optimize our diagnostic and therapeutic management of IFI in patients with acute leukemia, further basic research and clinical trials are desperately needed.

Antifungal efficacy during Candida krusei infection in non-conventional models correlates with the yeast in vitro susceptibility profile

The incidence of opportunistic fungal infections has increased in recent decades due to the growing proportion of immunocompromised patients in our society. Candida krusei has been described as a causative agent of disseminated fungal infections in susceptible patients. Although its prevalence remains low among yeast infections (2-5%), its intrinsic resistance to fluconazole makes this yeast important from epidemiologic aspects. Non mammalian organisms are feasible models to study fungal virulence and drug efficacy. In this work we have used the lepidopteran Galleria mellonella and the nematode Caenorhabditis elegans as models to assess antifungal efficacy during infection by C. krusei. This yeast killed G. mellonella at 25, 30 and 37°C and reduced haemocytic density. Infected larvae melanized in a dose-dependent manner. Fluconazole did not protect against C. krusei infection, in contrast to amphotericin B, voriconazole or caspofungin. However, the doses of these antifungals required to obtain larvae protection were always higher during C. krusei infection than during C. albicans infection. Similar results were found in the model host C. elegans. Our work demonstrates that non mammalian models are useful tools to investigate in vivo antifungal efficacy and virulence of C. krusei.

Nationwide study of candidemia, antifungal use, and antifungal drug resistance in Iceland, 2000 to 2011

Candidemia is often a life-threatening infection, with highly variable incidence among countries. We conducted a nationwide study of candidemia in Iceland from 2000 to 2011, in order to determine recent trends in incidence rates, fungal species distribution, antifungal susceptibility patterns, and concurrent antifungal consumption. A total of 208 infection episodes in 199 patients were identified. The average incidence during the 12 years was 5.7 cases/100,000 population/year, which was significantly higher than that from 1990 to 1999 (4.3/100,000/year; P = 0.02). A significant reduction in the use of blood cultures was noted in the last 3 years of the study, coinciding with the economic crisis in the country (P < 0.001). Age-specific incidence rates were highest among patients at the extremes of age, 20.7/100,000 for <1 year of age and 18.1/100,000 for >60 years, and varied by gender. Age-specific incidence among males >80 years old was 28.6/100,000/year, and it was 8.3/100,000/year for females in this age group (P = 0.028). The 30-day survival rate among adult patients remained unchanged compared to that from 1990 to 1999 (70.4% versus 69.5%, P = 0.97). Candida albicans was the predominant species (56%), followed by C. glabrata (16%) and C. tropicalis (13%). The species distribution remained stable compared to that from previous decades. Fluconazole use increased 2.4-fold from 2000 to 2011, with no increase in resistance. In summary, the incidence of candidemia in Iceland has continued to increase but may have reached a steady state, and no increase in antifungal drug resistance has been noted. Decreased use of blood cultures toward the end of the study may have influenced detection rates.

Catheter-related fungemia caused by Candida dubliniensis

Infections caused by Candida dubliniensis in humans are rare and have never been reported in Taiwan. We report two cancer patients with catheter-related fungemia due to C. dubliniensis infection in Taiwan. The two isolates were confirmed to the species level using an oligonucleotide array system and sequence analysis, and both showed high in vitro susceptibilities to nine antifungal agents. The catheters were removed, and both patients responded well to antifungal treatment. Although this type of infection is rare, physicians should consider C. dubliniensis as one of the possible pathogens causing catheter-related infections in Taiwan.

Mortality in patients with early- or late-onset candidaemia

OBJECTIVES

Although candidaemia is a well-known complication of hospital stay and has a crude mortality of ∼40%, few data are available for episodes diagnosed within 10 days after hospital admission. In this paper, we compared the risk factors for mortality according to the onset of candidaemia.

METHODS

This was a retrospective study of hospitalized patients with early-onset candidaemia (EOC; ≤ 10 days) or late-onset candidaemia (LOC; >10 days) to identify any distinct clinical characteristics and risk factors for 30 day mortality in two Italian academic centres.

RESULTS

A total of 779 patients were included in the study: 183 EOC and 596 LOC. Mortality was significantly lower in EOC (71/183, 38.8% versus 283/596, 47.5%, P=0.03). In EOC, multivariate analysis showed that inadequate initial antifungal therapy (IIAT) (P=0.005, OR 3.02, 95% CI 1.40-6.51), Candida albicans aetiology (P=0.02, OR 2.17, 95% CI 1.11-4.26) and older age (P<0.001, OR 1.05, 95% CI 1.02-1.07) were independent risk factors for mortality. In LOC, liver disease (P=0.003, OR 2.46, 95% CI 1.36-4.43), IIAT (P=0.002, OR 2.01, 95% CI 1.28-3.15) and older age (P<0.001, OR 1.03, 95% CI 1.02-1.04) were independently associated with a fatal outcome, while treatment with caspofungin was associated with survival (P<0.001, OR 0.42, 95% CI 0.26-0.67).

CONCLUSIONS

EOC has different clinical characteristics and risk factors for mortality compared with LOC. Although EOC mortality is significantly lower, the rate of inappropriate antifungal treatment is higher. Treatment with caspofungin is significantly associated with survival in patients with LOC. Efforts are needed to improve the diagnosis and treatment of EOC.

The PATH (Prospective Antifungal Therapy) Alliance® registry and invasive fungal infections: update 2012

The Prospective Antifungal Therapy Alliance (PATH Alliance®) performed prospective surveillance of invasive fungal infections (IFIs) among patients hospitalized at 25 medical centers in North America between 2004 and 2008, collecting information on the epidemiology, diagnosis, treatment, and mortality rates of IFIs. In total, 7526 IFIs were identified in 6845 patients. Candida spp. (73.4%) were the most common pathogens, followed by Aspergillus spp. (13.3%), and other yeasts (6.2%). Culture was the most frequently used diagnostic test in the majority of IFI categories. Most patients with invasive candidiasis were treated with fluconazole (48.3%) and the echinocandins (34.0%), while voriconazole (45.5%) was the main antifungal agent for invasive aspergillosis. The 12-week survival rate ranged from 37.5% for hematopoietic stem cell transplant recipients to ~75.0% for those with HIV/AIDS. In summary, the findings of the PATH Alliance® registry provide a better understanding of the epidemiology of a vast variety and large numbers of IFIs.

Species identification and antifungal susceptibility testing of Candida bloodstream isolates from population-based surveillance studies in two U.S. cities from 2008 to 2011

Between 2008 and 2011, population-based candidemia surveillance was conducted in Atlanta, GA, and Baltimore, MD. Surveillance had been previously performed in Atlanta in 1992 to 1993 and in Baltimore in 1998 to 2000, making this the first population-based candidemia surveillance conducted over multiple time points in the United States. From 2,675 identified cases of candidemia in the current surveillance, 2,329 Candida isolates were collected. Candida albicans no longer comprised the majority of isolates but remained the most frequently isolated species (38%), followed by Candida glabrata (29%), Candida parapsilosis (17%), and Candida tropicalis (10%). The species distribution has changed over time; in both Atlanta and Baltimore the proportion of C. albicans isolates decreased, and the proportion of C. glabrata isolates increased, while the proportion of C. parapsilosis isolates increased in Baltimore only. There were 98 multispecies episodes, with C. albicans and C. glabrata the most frequently encountered combination. The new species-specific CLSI Candida MIC breakpoints were applied to these data. With the exception of C. glabrata (11.9% resistant), resistance to fluconazole was very low (2.3% of isolates for C. albicans, 6.2% for C. tropicalis, and 4.1% for C. parapsilosis). There was no change in the proportion of fluconazole resistance between surveillance periods. Overall echinocandin resistance was low (1% of isolates) but was higher for C. glabrata isolates, ranging from 2.1% isolates resistant to caspofungin in Baltimore to 3.1% isolates resistant to anidulafungin in Atlanta. Given the increase at both sites and the higher echinocandin resistance, C. glabrata should be closely monitored in future surveillance.

In vitro susceptibilities of yeast species to fluconazole and voriconazole as determined by the 2010 National China Hospital Invasive Fungal Surveillance Net (CHIF-NET) study

We conducted active, laboratory-based surveillance for isolates from patients with invasive infections across China from August 2009 to July 2010. DNA sequencing methods were used to define species, and susceptibility to fluconazole and voriconazole was determined by the Clinical and Laboratory Standards Institute M44-A2 disk diffusion method but using up-to-date clinical breakpoints or epidemiological cutoff values. Candida spp. made up 90.5% of the 814 yeast strains isolated, followed by Cryptococcus neoformans (7.7%) and other non-Candida yeast strains (1.7%). Bloodstream isolates made up 42.9% of the strains, isolates from ascitic fluid made up 22.1%, but pus/tissue specimens yielded yeast strains in <5% of the cases. Among the Candida isolates, Candida albicans was the most common species from specimens other than blood (50.1%) but made up only 23% of the bloodstream isolates (P < 0.001). C. parapsilosis complex species were the most common Candida isolates from blood (33.2%). Uncommon bloodstream yeast strains included Trichosporon spp., C. pelliculosa, and the novel species C. quercitrusa, reported for the first time as a cause of candidemia. Most (>94%) of the isolates of C. albicans, C. tropicalis, and the C. parapsilosis complex were susceptible to fluconazole and voriconazole, as were all of the Trichosporon strains; however, 12.2% of the C. glabrata sensu stricto isolates were fluconazole resistant and 17.8% had non-wild-type susceptibility to voriconazole. Seven C. tropicalis strains were cross-resistant to fluconazole and voriconazole; six were from patients in the same institution. Resistance to fluconazole and voriconazole was seen in 31.9% and 13.3% of the uncommon Candida and non-Candida yeast strains, respectively. Causative species and azole susceptibility varied with the geographic region. This study provided clinically useful data on yeast strains and their antifungal susceptibilities in China.

Accurate and rapid identification of Candida spp. frequently associated with fungemia by using PCR and the microarray-based Prove-it Sepsis assay

The rapid identification of microbes responsible for bloodstream infections (BSIs) allows more focused and effective therapies and outcomes. DNA sequence-based methods offer an opportunity for faster, accurate diagnosis and for effective therapy. As our objective of the study, the ability of the Prove-it Sepsis platform, already proven as a rapid PCR- and microarray-based assay for the majority of sepsis-causing bacteria, was extended to also rapidly identify clinically relevant yeasts in blood culture. The performance characteristics of this extended platform are described. We found that the extended diagnostic Prove-it Sepsis platform was found to be highly accurate when analyzing primary isolates, spiked blood cultures, nucleic acid extracts from a retrospective blood culture data set, and primary blood cultures. Comparison of the blood culture results from the Prove-it Sepsis platform with those from conventional culture-based methods or by gene sequencing demonstrated a sensitivity of 99% and a specificity of 98% for fungal targets (based on analysis of a total of 388 specimens). Total assay time was 3 h from DNA extraction to BSI diagnosis. These results extend the performance characteristics of the Prove-it platform for bacteria to the easy, rapid, and accurate detection and species identification of yeasts in positive blood cultures. Incorporation of this extended and rapid diagnostic platform into the tools for clinical patient management would allow possibly faster identification and more focused therapies for BSIs.

Candida dubliniensis: an appraisal of its clinical significance as a bloodstream pathogen

A nine-year prospective study (2002–2010) on the prevalence of Candida dubliniensis among Candida bloodstream isolates is presented. The germ tube positive isolates were provisionally identified as C. dubliniensis by presence of fringed and rough colonies on sunflower seed agar. Subsequently, their identity was confirmed by Vitek2 Yeast identification system and/or by amplification and sequencing of the ITS region of rDNA. In all, 368 isolates were identified as C. dubliniensis; 67.1% came from respiratory specimens, 11.7% from oral swabs, 9.2% from urine, 3.8% from blood, 2.7% from vaginal swabs and 5.4% from other sources. All C. dubliniensis isolates tested by Etest were susceptible to voriconazole and amphotericin B. Resistance to fluconazole (≥8 µg/ml) was observed in 2.5% of C. dubliniensis isolates, 7 of which occurred between 2008–2010. Of note was the diagnosis of C. dubliniensis candidemia in 14 patients, 11 of them occurring between 2008–2010. None of the bloodstream isolate was resistant to fluconazole, while a solitary isolate showed increased MIC to 5-flucytosine (>32 µg/ml) and belonged to genotype 4. A review of literature since 1999 revealed 28 additional cases of C. dubliniensis candidemia, and 167 isolates identified from blood cultures since 1982. In conclusion, this study highlights a greater role of C. dubliniensis in bloodstream infections than hitherto recognized.

Proanthocyanidin-rich extracts from cranberry fruit (Vaccinium macrocarpon Ait.) selectively inhibit the growth of human pathogenic fungi Candida spp. and Cryptococcus neoformans

Cranberry ( Vaccinium macrocarpon ) has been shown in clinical studies to reduce infections caused by Escherichia coli and other bacteria, and proanthocyanidins are believed to play a role. The ability of cranberry to inhibit the growth of opportunistic human fungal pathogens that cause oral, skin, respiratory, and systemic infections has not been well-studied. Fractions from whole cranberry fruit were screened for inhibition of five Candida species and Cryptococcus neoformans , a causative agent of fungal meningitis. Candida glabrata , Candida lusitaniae , Candida krusei , and Cryptococcus neoformans showed significant susceptibility to treatment with cranberry proanthocyanidin fractions in a broth microdilution assay, with minimum inhibitory concentrations as low as 1 μg/mL. MALDI-TOF MS analysis of subfractions detected epicatechin oligomers of up to 12 degrees of polymerization. Those containing larger oligomers caused the strongest inhibition. This study suggests that cranberry has potential as an antifungal agent.

Diagnostic issues, clinical characteristics, and outcomes for patients with fungemia

This study investigated microbiological, clinical, and management issues and outcomes for Danish fungemia patients. Isolates and clinical information were collected at six centers. A total of 334 isolates, 316 episodes, and 305 patients were included, corresponding to 2/3 of the national episodes. Blood culture positivity varied by system, species, and procedure. Thus, cases with concomitant bacteremia were reported less commonly by BacT/Alert than by the Bactec system (9% [11/124 cases] versus 28% [53/192 cases]; P < 0.0001), and cultures with Candida glabrata or those drawn via arterial lines needed longer incubation. Species distribution varied by age, prior antifungal treatment (57% occurrence of C. glabrata, Saccharomyces cerevisiae, or C. krusei in patients with prior antifungal treatment versus 28% occurrence in those without it; P = 0.007), and clinical specialty (61% occurrence of C. glabrata or C. krusei in hematology wards versus 27% occurrence in other wards; P = 0.002). Colonization samples were not predictive for the invasive species in 11/100 cases. Fifty-six percent of the patients had undergone surgery, 51% were intensive care unit (ICU) patients, and 33% had malignant disease. Mortality increased by age (P = 0.009) and varied by species (36% for C. krusei, 25% for C. parapsilosis, and 14% for other Candida species), severity of underlying disease (47% for ICU patients versus 24% for others; P = 0.0001), and choice but not timing of initial therapy (12% versus 48% for patients with C. glabrata infection receiving caspofungin versus fluconazole; P = 0.023). The initial antifungal agent was deemed suboptimal upon species identification in 15% of the cases, which would have been 6.5% if current guidelines had been followed. A large proportion of Danish fungemia patients were severely ill and received suboptimal initial antifungal treatment. Optimization of diagnosis and therapy is possible.

Cost-effectiveness analysis of anidulafungin versus fluconazole for the treatment of invasive candidiasis

BACKGROUND

Anidulafungin was found to be non-inferior to and possibly more efficacious than fluconazole for treatment of invasive candidiasis (IC) in a major randomized clinical trial (RCT). There are no data comparing the cost-effectiveness between azoles and echinocandins in treating IC. This economic analysis investigated the cost-effectiveness of anidulafungin compared with fluconazole for treatment of IC in an Australian setting.

METHODS

A decision analytic model was constructed to capture downstream consequences of using either agent for treatment of IC. The main outcomes analysed in the model were treatment success and treatment failure (observed and indeterminate). Outcome probabilities and treatment pathways were derived from a published RCT. Resources used were estimated by an expert panel and cost inputs were derived from the latest Australian resources. The analysis was based on an Australian hospital perspective. Sensitivity analyses were conducted using Monte Carlo simulation.

RESULTS

Anidulafungin (AU$74,587) had a higher total cost than fluconazole (AU$60,945) per successfully treated patient, primarily due to its higher acquisition cost. Hospitalization was the main cost driver for both comparators. However, when the rates of mortality in both treatment arms were considered, treatment with anidulafungin was expected to save an additional 0.53 life-years, with an incremental cost-effectiveness ratio (ICER) of AU$25 740 per life-years saved, which was below the implicit ICER threshold value for Australia. The results were robust over a wide range of variables.

CONCLUSIONS

This is the first economic evaluation of anidulafungin versus fluconazole in the treatment of IC in Australia. Anidulafungin appears to be a cost-effective option.

Epidemiology of invasive candidiasis

PURPOSE OF REVIEW

This review covers candidaemia in numbers, susceptibility issues, host groups, risk factors and outcome.

RECENT FINDINGS

The incidence of candidaemia has increased over the last decades. Candida glabrata is particularly common in the northern hemisphere and with increasing age whilst the opposite is true for C. parapsilosis, C. glabrata, C. krusei and a number of emerging species are not fully susceptible to azoles. C. parapsilosis and C. guilliermondii are not fully susceptible to echinocandins. Increasing rates of C. parapsilosis have been observed at centres with a high use of echinocandins, and outcome for this species is not superior comparing echinocandins with fluconazole. Acquired azole resistance has recently been described in as many as a third of 19% resistant isolates and echinocandin resistance has emerged and been detected as early as day 12 of echinocandin therapy. ICU stay and abdominal surgery are among the most important risk factors. Outcome is dependent on species involved, timing, dosing and choice of therapy and management of the primary focus of infection. However, host factors are dominating predictors of mortality in recent studies of ICU candidiasis.

SUMMARY

The changing epidemiology highlights the need for close monitoring of local incidence, species distribution and susceptibility in order to optimize therapy and outcome.

National surveillance of fungemia in Denmark (2004 to 2009)

A 6-year nationwide study of fungemia in Denmark was performed using data from an active fungemia surveillance program and from laboratory information systems in nonparticipating regions. A total of 2,820 episodes of fungemia were recorded. The incidence increased from 2004 to 2007 (7.7 to 9.6/100,000) and decreased slightly from 2008 to 2009 (8.7 to 8.6/100,000). The highest incidences were seen at the extremes of age (i.e., 11.3 and 37.1/100,000 for those <1 and 70 to 79 years old, respectively). The rate was higher for males than for females (10.1 versus 7.6/100,000, P = 0.003), with the largest difference observed for patients >50 years of age. The species distribution varied significantly by both age and gender. Candida species accounted for 98% of the pathogens, and C. albicans was predominant, although the proportion decreased (64.4% to 53.2%, P < 0.0001). C. glabrata ranked second, and the proportion increased (16.5% to 25.9%, P = 0.003). C. glabrata was more common in adults and females than in children and males, whereas C. tropicalis was more common in males (P = 0.020). C. krusei was a rare isolate (4.1%) except at one university hospital. Acquired resistance to amphotericin and echinocandins was rare. However, resistance to fluconazole (MIC of >4 μg/ml) occurred in C. albicans (7/1,183 [0.6%]), C. dubliniensis (2/65 [3.1%]), C. parapsilosis (5/83 [6.0%]), and C. tropicalis (7/104 [6.7%]). Overall, 70.8% of fungemia isolates were fully fluconazole susceptible, but the proportion decreased (79.7% to 68.9%, P = 0.02). The study confirmed an incidence rate of fungemia in Denmark three times higher than those in other Nordic countries and identified marked differences related to age and gender. Decreased susceptibility to fluconazole was frequent and increasing.

Candida bloodstream infections: comparison of species distributions and antifungal resistance patterns in community-onset and nosocomial isolates in the SENTRY Antimicrobial Surveillance Program, 2008-2009

Community-onset (CO) candidemia, defined as a positive blood culture taken at or within 2 days of hospital admission, represents a distinct clinical entity associated with substantial morbidity and mortality. Reference MIC results from the SENTRY Antimicrobial Surveillance Program (2008-2009) were analyzed to compare the antifungal resistance patterns and species distributions from patients with CO and nosocomial bloodstream infections (BSI) in 79 medical centers. Among 1,354 episodes of BSI, 494 (36.5%) were classified as CO and 860 (63.5%) as nosocomial in origin. More than 95% of the isolates from both BSI types were contributed by Candida albicans (48.4%), C. glabrata (18.2%), C. parapsilosis (17.1%), C. tropicalis (10.6%), and C. krusei (2.0%). C. albicans was more common in CO BSI (51.0%) than nosocomial BSI (46.9%), whereas C. parapsilosis and C. krusei were more common in nosocomial BSIs (18.1 and 2.7%, respectively) than in CO BSIs (15.4 and 0.8%, respectively). C. glabrata and C. tropicalis were comparable in both CO (18.4 and 10.5%, respectively) and nosocomial (18.1 and 10.6%, respectively) episodes. Resistance to azoles (fluconazole, posaconazole, and voriconazole) and echinocandins (anidulafungin, caspofungin, and micafungin) was uncommon (<5%) in CO BSI using recently established Clinical and Laboratory Standards Institute breakpoint criteria. Resistance to echinocandins (anidulafungin [3.8%], caspofungin [5.1%], and micafungin [3.2%]) and azoles (fluconazole [7.7%], posaconazole [5.1%], and voriconazole [6.4%]) was most prevalent among nosocomial BSI isolates of C. glabrata. CO candidemia is not uncommon and appears to be increasing worldwide due to changing health care practices. Although resistance to the azoles and echinocandins remains uncommon among CO isolates, we demonstrate the emergence of nosocomial occurrences of C. glabrata expressing resistance to both monitored classes of antifungal agents.

Recent exposure to caspofungin or fluconazole influences the epidemiology of candidemia: a prospective multicenter study involving 2,441 patients

A prospective multicenter surveillance program on yeast bloodstream infections was implemented in the Paris, France, area without restrictions on ward of hospitalization (intensive care unit, hematology, and surgery) or age (adults and children). The present analysis concerns 2,618 isolates collected over 7 years from 2,441 patients. Centralized species identification and antifungal susceptibility testing using the EUCAST methodology were performed. Almost 10% (232/2,441) of the patients had recently (≤30 days) been treated with antifungal drugs. We analyzed the effect of recent exposure to fluconazole (n = 159) or caspofungin (n = 61) on the proportions of the five major Candida species. For both drugs, preexposure was associated with a decreased prevalence of Candida albicans in favor of less drug-susceptible species (C. glabrata and C. krusei for the former and C. parapsilosis and, to a lesser extent, C. glabrata and C. krusei for the latter; P = 0.001). In the multivariate analysis, the risk of being infected with an isolate with decreased susceptibility to fluconazole was independently associated with an age of ≥15 years (odds ratio [OR] = 2.45; 95% confidence interval [CI] = 1.39 to 4.31; P = 0.002) and with recent exposure to fluconazole (OR = 2.17; 95% CI = 1.51 to 3.13; P < 0.001), while the risk of being infected with an isolate with decreased susceptibility to caspofungin was independently associated with an age <15 years (OR = 2.53; 95% CI = 1.43 to 4.48; P = 0.001) and with recent exposure to caspofungin (OR = 4.79; 95% CI = 2.47 to 9.28; P < 0.001). These findings could influence future recommendations for the management of candidemia.

Year in review 2009: Critical Care--infection

In 2009 Critical Care provided important and clinically relevant research data for management and prevention of infections in critically ill patients. The present review summarises the results of these observational studies and clinical trials and discusses them in the context of the current relevant scientific and clinical background. In particular, we discuss recent epidemiologic data on nosocomial infections in intensive care units, present new approaches to prevention of ventilator-associated pneumonia, describe recent advances in biomarker-guided antibiotic stewardship and attempt to briefly summarise specific challenges related to the management of infections caused by multidrug-resistant microorganisms and influenza A (H1N1).