Susceptibility patterns of Candida species recovered from Canadian intensive care units

A study on candiduria in neonates and infants from a tertiary care center, North India

PURPOSE

Candida albicans is the major cause of fungal UTI in neonates and infants but nowadays non albicans Candida is also increasing and these are mostly multidrug resistant. So it's important to know the species of candidal UTI for the proper management. This study was undertaken to determine the Candida species distribution in UTI along with their susceptibility pattern and outcome in infants and neonates admitted in different wards and ICU of our hospital. We also assess the incidence rate of candiduria in ICUs.

METHOD

Urine samples were collected from infants and neonates presented in pediatrics and neonatal ICU (intensive care units) and clinical wards with a clinical suspicion of candiduria and infants at risk of invasive candidiasis were also included in the study. Identification of Candida sp. was done by Gram's staining, germ tube test, chlamydospore formation on corn meal agar, color appearance on CHROM agar and also confirmed by MALDI-TOF Assay. Antifungal susceptibility was performed by using broth microdilution method as per the CLSI M27-A3/M27-S4.

RESULT

Urine samples were received from 219 infants, and Candida was isolated from samples from 52 infants (isolation rate 23.75%), of which 30 were admitted in pediatric or neonatal ICU and 22 in the wards. The incidence rate of candiduria in ICU was 3.25%. Candida albicans was the most frequently isolated species from the samples of infants in the wards (13/22 i.e. 59%), while Candida tropicalis was most frequently isolated from samples of infants in the ICUs (13/30 i.e. 43.34%). Candida glabrata was the least commonly isolated species and was only encopuntered in the ICU. There was no discrepancy between the results of conventional methods of identification and MALDI-TOF. Antifungal susceptibility was performed for 18 randomly selected isolates. All were found to be susceptible to caspofungin, micafungin, itraconazole, voriconazole, fluconazole, amphotericin B.

CONCLUSION

High suspicion of candiduria is needed especially in ICU admitted infants and identification of candida at species level along with the susceptibility pattern is important for the better management of patients.

Candidemia in intensive care units over nine years at a large Italian university hospital: Comparison with other wards

Purpose

Candidemia is an alarming problem in critically ill patients including those admitted in intensive care units (ICUs). We aimed to describe the clinical and microbiological characteristics of bloodstream infections (BSIs) due to Candida spp. in patients admitted to ICUs of an italian tertiary referral university hospital over nine years.

Methods

A retrospective observational study of all cases of candidemia in adult patients was carried out from January 1, 2010 to December 31, 2018 at a 980-bedded University Hospital in Ancona, Italy, counting five ICUs. The incidence, demographics, clinical and microbiologic characteristics, therapeutic approaches and outcomes of ICU-patients with candidemia were collected. Non-ICU patients with candidemia hospitalized during the same time period were considered for comparison purposes. Early (7 days from the occurrence of the episode of Candida BSI) and late (30 days) mortality rates were calculated.

Results

During the study period, 188/505 (36%) episodes of candidemia occurred in ICU patients. Cumulative incidence was 9.9/1000 ICU admission and it showed to be stable over time. Candida albicans accounted for 52% of the cases, followed by C. parapsilosis (24%), and C. glabrata (14%). There was not a significant difference in species distribution between ICU and non-ICU patients. With the exception of isolates of C. tropicalis which showed to be fluconazole resistant in 25% of the cases, resistance to antifungals was not of concern in our patients. Early and late mortality rates, were 19% and 41% respectively, the latter being significantly higher than that observed in non-ICU patients. At multivariate analysis, factors associated with increased risk of death were septic shock, acute kidney failure, pulmonary embolism and lack of antifungal therapy. The type of antifungal therapy did not influence the outcome. Mortality did not increased significantly over time.

Conclusion

Neither cumulative incidence nor crude mortality of candidemia in ICU patients increased over time at our institution. However, mortality rate remained high and significantly associated with specific host-related factors in the majority of cases.

Branched amphotericin functional poly(N-isopropyl acrylamide): an antifungal polymer

Branched poly(N-isopropylacrylamide) was functionalized with Amphotericin B (AmB) at the chain ends to produce an antifungal material. The polymer showed antifungal properties against AmB-sensitive strains of Candida albicans, Fusarium keratoplasticum and Aspergillus flavus (minimal inhibitory concentration ranged from 5 to 500 µg ml^-1) but was not effective against an AmB resistant strain of C. albicans nor against Candida tropicalis. The polymer end groups bound to the AmB target, ergosterol, and the fluorescence spectrum of a dye used as a solvatochromic probe, Nile red, was blue shifted indicating that segments of the polymer became desolvated on binding. The polymer was less toxic to corneal and renal epithelial cells and explanted corneal tissue than the free drug. Also, the polymer did not induce reactive oxygen species release from peripheral blood mononuclear cells, nor did it cause a substantial release of the proinflammatory cytokines, tumour necrosis factor-α and interleukin-1β (at 0.5 mg ml^-1).

A seven-year surveillance of Candida bloodstream infection at a university hospital in KSA

Objectives

Candidemia incidence has increased in the past few years, with high mortality. Previous studies have reported a variable distribution of Candida spp. among different regions. This study aimed to identify the species found in Candida bloodstream infections, routine antifungal susceptibility testing, and mortality outcomes in an academic medical centre.

Methods

Between January 2012 and December 2018, the positive blood cultures for candidemia infection were retrieved and statistically analysed for species prevalence, susceptibility pattern, and crude mortality at 14, 30, 60 and 90 days.

Results

Of 156 candidemia cases, a majority (69.2%) was caused by non-albicans Candida spp. After Candida albicans (30.8%), Candida tropicalis and Candida parapsilosis were the second and third most frequeunt isolates spp, each counting for 23.7%. Acquired resistance was detected in 14.8% of candidemia strains. No other antifungal resistance was detected. The overall crude mortality rates of all species were 29.3%, 47.9%, 56.4%, and 58.0% at 14, 30, 60, and 90 days, respectively. A higher mortality rate was noted in cases of Candida krusei infection (crude mortality 71.4–100%, p = 0.002).

Conclusion

In this study, a considerable shift to non-albicans Candida causing most bloodstream infections was observed. As such infections pose a serious threat to hospitalised patients, microbiology laboratories are urged to adopt rapid diagnostic and minimal inhibitory concentration-based testing for the detection of susceptible dose-dependent phenotypes. Prospective studies are essential to consider the prognosis of bloodstream infections by various Candida species in a multivariate model.

Invasive Candidiasis in Critically Ill Patients: A Prospective Cohort Study in Two Tertiary Care Centers

Background:

Invasive candidiasis is not uncommon in critically ill patients but has variable epidemiology and outcomes between intensive care units (ICUs). This study evaluated the epidemiology, characteristics, management, and outcomes of patients with invasive candidiasis at 6 ICUs of 2 tertiary care centers.

Methods:

This was a prospective observational study of all adults admitted to 6 ICUs in 2 different hospitals between August 2012 and May 2016 and diagnosed to have invasive candidiasis by 2 intensivists according to predefined criteria. The epidemiology of isolated Candida and the characteristics, management, and outcomes of affected patients were studied. Multivariable logistic regression analyses were performed to identify the predictors of non-albicans versus albicans infection and hospital mortality.

Results:

Invasive candidiasis was diagnosed in 162 (age 58.4 ± 18.9 years, 52.2% males, 82.1% medical admissions, and admission Acute Physiology and Chronic Health Evaluation II score 24.1 ± 8.4) patients at a rate of 2.6 cases per 100 ICU admissions. On the diagnosis day, the Candida score was 2.4 ± 0.9 in invasive candidiasis compared with 1.6 ± 0.9 in Candida colonization (P < .01). The most frequent species were albicans (38.3%), tropicalis (16.7%), glabrata (16%), and parapsilosis (13.6%). In patients with candidemia, antifungal therapy was started on average 1 hour before knowing the culture result (59.6% of therapy initiated after). Resistance to fluconazole, caspofungin, and amphotericin B occurred in 27.9%, 2.9%, and 3.1%, respectively. The hospital mortality was 58.6% with no difference between albicans and non-albicans infections (61.3% and 54.9%, respectively; P = .44). The independent predictors of mortality were renal replacement therapy after invasive candidiasis diagnosis (odds ratio: 5.42; 95% confidence interval: 2.16-13.56) and invasive candidiasis leading/contributing to ICU admission versus occurring during critical illness (odds ratio: 2.87; 95% confidence interval: 1.22-6.74).

Conclusions:

In critically ill patients with invasive candidiasis, non-albicans was responsible for most cases, and mortality was high (58.6%). Antifungal therapy was initiated after culture results in 60% suggesting low preclinical suspicion. Study registration: NCT01490684; registered in ClinicalTrials.gov on February 11, 2012.

Detection of neonatal unit clusters of Candida parapsilosis fungaemia by microsatellite genotyping: Results from laboratory-based sentinel surveillance, South Africa, 2009-2010

Neonatal candidaemia is a common, deadly and costly hospital-associated disease. To determine the genetic diversity of Candida parapsilosis causing fungaemia in South African neonatal intensive care units (NICUs). From February 2009 through to August 2010, cases of candidaemia were reported through laboratory-based surveillance. C. parapsilosis isolates from neonatal cases were submitted for identification by internal transcribed spacer (ITS) region sequencing, antifungal susceptibility testing and microsatellite genotyping. Cluster analysis was performed using Unweighted Pair Group Method with Arithmetic Mean (UPGMA). Of 1671 cases with a viable Candida isolate, 393 (24%) occurred among neonates. Isolates from 143 neonatal cases were confirmed as C. parapsilosis sensu stricto. Many isolates were resistant to fluconazole (77/143; 54%) and voriconazole (20/143; 14%). Of 79 closely-related genotypes, 18 were represented by ≥2 isolates; 61 genotypes had a single isolate each. Seven clusters, comprised of 82 isolates, were identified at five hospitals in three provinces. Isolates belonging to certain clusters were significantly more likely to be fluconazole resistant: all cluster 7 isolates and the majority of cluster 4 (78%), 5 (89%) and 6 (67%) isolates (P<.001). Candida parapsilosis-associated candidaemia in public-sector NICUs was caused by closely related genotypes and there was molecular evidence of undetected outbreaks as well as intra-hospital transmission.

Emerging drugs and vaccines for candidemia

Candidemia and other forms of invasive candidiasis are important causes of morbidity and mortality. The evolving challenge of antimicrobial resistance among fungal pathogens continues to highlight the need for potent, new antifungal agents. MEDLINE, EMBASE, Scopus and Web of Science searches (up to January 2014) of the English-language literature were performed with the keywords 'Candida' or 'Candidemia' or 'Candidiasis' and terms describing investigational drugs with activity against Candida spp. Conference abstracts and the bibliographies of pertinent articles were also reviewed for relevant reports. ClinicalTrials.gov was searched for relevant clinical trials. Currently available antifungal agents for the treatment of candidemia are summarised. Investigational antifungal agents with potential activity against Candida bloodstream infections and other forms of invasive candidiasis and vaccines for prevention of Candida infections are also reviewed as are selected antifungal agents no longer in development. Antifungal agents currently in clinical trials include isavuconazole, albaconazole, SCY-078, VT-1161 and T-2307. Further data are needed to determine the role of these compounds in the treatment of candidemia and other forms of invasive candidiasis. The progressive reduction in antimicrobial drug development may result in a decline in antifungal drug discovery. Still, there remains a critical need for new antifungal agents to treat and prevent invasive candidiasis and other life-threatening mycoses.

The Prospective Antifungal Therapy Alliance(®) registry: A two-centre Canadian experience

BACKGROUND

The Prospective Antifungal Therapy Alliance(®) registry is a prospective surveillance study that collected data on the diagnosis, management and outcomes of invasive fungal infections (IFIs) from 25 centres in North America from 2004 to 2008.

OBJECTIVE

To evaluate surveillance data on IFIs obtained from study centres located in Canada.

METHODS

Patients with proven or probable IFIs at two Canadian medical centres were enrolled in the registry. Information regarding patient demographics, fungal species, infection sites, diagnosis techniques, therapy and survival were analyzed.

RESULTS

A total of 347 patients from Canada with documented IFIs were enrolled in the Prospective Antifungal Therapy Alliance registry. Infections occurred most commonly in general medicine (71.8%), nontransplant surgery (32.6%) and patients with hematological malignancies (21.0%). There were 287 proven IFIs, including 248 Candida infections. Forty-six patients had invasive aspergillosis (IA); all of these were probable infections. Most cases of invasive candidiasis were confirmed using blood culture (90.5%), while IA was most frequently diagnosed using computed tomography scan (82.6%) and serological methods (82.6%). Fluconazole was the most common therapy used for Candida infections, followed by the echinocandins. Voriconazole therapy was most commonly prescribed for IA.

CONCLUSIONS

The present study demonstrated that general medicine, surgery and hematological malignancy patients in Canada are susceptible to developing IFIs. In contrast to the United States, Candida albicans remains responsible for most IFIs in these Canadian centres. Surrogate serum markers are commonly being used for the diagnosis of IA, while therapy for both IFIs has shifted to broader-spectrum azoles and echinocandins.

[Invasive fungal infection in critically ill patients]

The most common organism implicated in fungal infections in the critically ill patients is Candida spp. C. albicans continues to be the species that causes the largest number of invasive candidiasis. In critically ill patients, Candida spp. are frequently isolated in non-sterile sites. Candida colonization is documented in nearly 60% of non-neutropenic critically ill patients staying more than one week in the ICU. However, only 5% of colonized patients will develop invasive candidiasis. The diagnosis of invasive non-candidemic candidiasis remains elusive in the majority of the patients. Candida in a blood culture should never be viewed as a contaminant and should always prompt treatment initiation. Patients with multifocal colonization with a Candida score >3 should also receive antifungal therapy. Fluconazole is reserved for non-severely ill patients without recent exposure to azoles. The use of an echinocandin is recommended for hemodynamically unstable patients or with a history of recent fluconazole exposure.

Molecular epidemiology and antifungal susceptibility of Candida parapsilosis sensu stricto, Candida orthopsilosis, and Candida metapsilosis in Taiwan

Candida parapsilosis was recently reclassified into 3 closely related species, C. parapsilosis sensu stricto, Candida orthopsilosis, and Candida metapsilosis. Variation in susceptibility characteristics and prevalence of the 3 genomic species could have therapeutic and epidemiologic implications. The aim of this study is to characterize the genetic and antifungal susceptibility profiles of 97 C. parapsilosis isolates from 71 patients. Among the 71 nonduplicate isolates, 85.9% (61/71) were identified as C. parapsilosis sensu stricto, 5.6% (4/71) as C. metapsilosis, and 8.5% (6/71) as C. orthopsilosis species based on sequences of the internal transcribed spacer (ITS) region. The delineation of these 3 species is concordant with that achieved by pulsed-field gel electrophoresis of BssHII restriction fragments at 75% similarity. Antifungal susceptibility tests showed that most isolates were susceptible to flucytosine, azoles, amphotericin B, and echinocandins, whereas 3 C. metapsilosis isolates from 1 patient showed resistance and susceptible-dose dependence to fluconazole. The C. metapsilosis isolates exhibited significantly higher MIC values to both fluconazole and voriconazole than those of C. parapsilosis sensu stricto and C. orthopsilosis. On the other hand, the C. metapsilosis isolates showed significantly lower MIC values on 24 h to caspofungin than those of C. parapsilosis sensu stricto and C. orthopsilosis. For micafungin, the isolates of C. parapsilosis sensu stricto had significantly higher MIC values on 24 h than those of C. orthopsilosis and C. metapsilosis. Compared to Candida albicans, mutations from proline to alanine were identified on the hot spot 1 of Fks1 in all these C. parapsilosis sensu lato isolates regardless of their MIC levels. Some of the C. orthopsilosis and C. metapsilosis isolates expressed the isoleucine to valine substitution on the hot spot 2 region. However, the amino acid variations in these isolates did not correlate to their MIC values of echinocandin.

New triazoles and echinocandins: mode of action, in vitro activity and mechanisms of resistance

Different types of mycoses, especially invasive mycoses caused by yeasts and molds, are a growing problem in healthcare. The most notable explanation for this increase is a rise in the number of immunocompromised patients owing to advances in transplantation, the emergence of AIDS and a rise in the number of invasive surgical procedures. Despite advances in medical practice, some therapeutic problems remain. In addition, intrinsic or acquired antifungal resistance may pose a serious problem to antifungal therapy. A new generation of triazole agents (voriconazole, posaconazole, isavuconazole, ravuconazole and albaconazole) and the recent class of the echinocandins (caspofungin, micafungin and anidulafungin) have become available, and represent an alternative to conventional antifungals for serious fungal infection management. Currently, only two of the recent triazole generation (voriconazole and posaconazole) and all three echinocandins are available for clinical use. More precisely, voriconazole and posaconazole are indicated for the treatment of invasive fungal infections and the echinocandins for the treatment of specific candidiasis. Voriconazole and posaconazole have a very broad spectrum of antifungal activity that includes Candida species, and filamentous and dimorphic fungi. Their activity extends to both fluconazole- and itraconazole-resistant strains of Candida. A major difference between posaconazole and voriconazole is that posaconazole has activity against Zygomycetes including Mucor spp., Rhizopus spp. and Cunninghamella spp., and voriconazole has no activity against this class of fungi. Ravuconazole, isavuconazole and albaconazole have shown very potent in vitro activity against species of Candida, Cryptococcus and Aspergillus, and they are currently in various stages of development. All three echinocandin agents, caspofungin, micafungin and anidulafungin, are similar in their spectrum of activity. Echinocandins do not possess in vitro activity against important basidiomycetes, including Cryptococcus, Rhodotorula and Trichosporon. This review attempts to deliver the most up-to-date knowledge on the mode of action and mechanisms of resistance to triazoles and echinocandins in fungal pathogens. In addition, the in vitro activity data available on triazoles and echinocandins are reported.

Candida parapsilosis: a review of its epidemiology, pathogenesis, clinical aspects, typing and antimicrobial susceptibility

The Candida parapsilosis family has emerged as a major opportunistic and nosocomial pathogen. It causes multifaceted pathology in immuno-compromised and normal hosts, notably low birth weight neonates. Its emergence may relate to an ability to colonize the skin, proliferate in glucose-containing solutions, and adhere to plastic. When clusters appear, determination of genetic relatedness among strains and identification of a common source are important. Its virulence appears associated with a capacity to produce biofilm and production of phospholipase and aspartyl protease. Further investigations of the host-pathogen interactions are needed. This review summarizes basic science, clinical and experimental information about C. parapsilosis.

Species distribution and susceptibility profile of Candida species in a Brazilian public tertiary hospital

Background

Species identification and antifungal susceptibility tests were carried out on 212 Candida isolates obtained from bloodstream infections, urinary tract infections and dialysis-associated peritonitis, from cases attended at a Brazilian public tertiary hospital from January 1998 to January 2005.

Findings

Candida albicans represented 33% of the isolates, Candida parapsilosis 31.1%, Candida tropicalis 17.9%,Candida glabrata 11.8%, and others species 6.2%. In blood culture, C. parapsilosis was the most frequently encountered species (48%). The resistance levels to the antifungal azoles were relatively low for the several species, except for C. tropicalis and C. glabrata. Amphotericin B resistance was observed in 1 isolate of C. parapsilosis.

Conclusions

The species distribution and antifungal susceptibility herein observed presented several epidemiological features common to other tertiary hospitals in Latin American countries. It also exhibited some peculiarity, such as a very high frequency of C. parapsilosis both in bloodstream infections and dialysis-associated peritonitis. C. albicans also occurred in an important number of case infections, in all evaluated clinical sources. C. glabrata presented a high proportion of resistant isolates. The data emphasize the necessity to carry out the correct species identification accompanied by the susceptibility tests in all tertiary hospitals.

Surveillance for antimicrobial resistant organisms: potential sources and magnitude of bias

Surveillance has been recognized as a fundamental component in the control of antimicrobial- resistant infections. Although surveillance data have been widely published and utilized by researchers and decision makers, little attention has been paid to assessment of their validity. We conducted this review in order to identify and explore potential types and magnitude of bias that may influence the validity or interpretation of surveillance data. Six main potential areas were assessed. These included bias related to use of inadequate or inappropriate (1) denominator data, (2) case definitions, and (3) case ascertainment; (4) sampling bias; (5) failure to deal with multiple occurrences, and (6) those related to laboratory practice and procedures. The magnitude of these biases varied considerably for the above areas within different study populations. There are a number of potential biases that should be considered in the methodological design and interpretation of antimicrobial-resistant organism surveillance.

Activity profile in vitro of micafungin against Spanish clinical isolates of common and emerging species of yeasts and molds

A collection of 2,278 isolates belonging to 86 different fungal species was tested with micafungin and eight other drugs using the EUCAST procedures. Micafungin was active against species of Candida and Aspergillus (even azole-resistant species) as well as Penicillium spp., Scedosporium apiospermum, and Acremonium spp. It was inactive for species of Basidiomycota and Mucorales and for multiresistant species such as those of Fusarium.

The echinocandin caspofungin impairs the innate immune mechanism against Candida parapsilosis

Since caspofungin inhibits fungal cell wall beta-glucan synthesis and the fungal cell wall plays an important role in the recognition of Candida by phagocytic cells, we studied phagocytosis in the presence of caspofungin. The aim of this work was to investigate the effect of pre-treatment of Candida parapsilosis with caspofungin on phagocytic mechanisms (opsonisation, oxidative burst, phagocytosis and killing). C. parapsilosis grown in the presence of caspofungin at concentrations above the minimal inhibitory concentration (MIC) were more difficult to opsonise and to phagocytose. C. parapsilosis exposed to any concentration of caspofungin below and above the MIC was more difficult to kill. Caspofungin-treated C. parapsilosis impaired the oxidative burst. Overall, it appears that caspofungin treatment of C. parapsilosis alters the capacity of polymorphonuclear leukocytes to phagocytose and delays killing of the organism. This may allow C. parapsilosis to persist in tissues.