Epidemiology of candidaemia in critically ill trauma patients: experiences of a level I trauma centre in North India

Loop-mediated isothermal amplification for Candida species surveillance in under-resourced setting: a review of evidence

INTRODUCTION

Non-albicans Candida species (NACS) have emerged as a major public health burden although they are still underappreciated. Some NACS have intrinsic antifungal resistance, requiring constant surveillance to improve patient care and thwart outbreaks of recalcitrant candida infections. However, effective Candida species surveillance has relied on PCR-based or other high-end techniques that are largely unaffordable in under-resourced countries. Loop-mediated isothermal amplification (LAMP) has emerged as a potentially effective and affordable technique for infectious disease surveillance, especially in under resourced settings.

AREAS COVERED

We critically reviewed current literature on application of LAMP for Candida species identification in pure fungal isolates, and in clinical and non-clinical samples.

EXPERT OPINION

LAMP has been studied for Candida species identification, including the NACS. Besides a short turnaround time, LAMP has analytical sensitivity and specificity that are not only higher than culture method but also comparable with conventional and quantitative PCR techniques. However, extensive evaluation of LAMP for Candida species detection using various types of clinical and environmental samples are required before deploying the technique for Candida species surveillance.

A complete clinico-epidemiological and microbiological profile of candidemia cases in a tertiary-care hospital in Western India

Objective:

To identify different Candida spp along with antifungal susceptibility pattern and risk factors associated with candidemia.

Design, setting, and patients:

This retrospective observational study was conducted in a tertiary-care academic hospital in Jaipur, Western India, for 3 years (July 2017–June 2020).

Methods:

Blood cultures were performed according to standard microbiological methods, and only 1 isolate per patient was included in the study. Isolates of Candida spp were identified using a VITEK-2 automated system and matrix-assisted laser desorption ionization-time of flight mass spectrometry. Antifungal susceptibility tests were performed using the broth microdilution assay according to the Clinical and Laboratory Standards Institute guidelines.

Results:

Of 3,443 blood cultures received from suspected sepsis cases, candidemia was identified in 95 (2.8%). In addition to Candida tropicalis (n = 36; 38%) and Candida parapsilosis (n = 17; 18%), 10 isolates of Candida auris comprised the fourth most common cause of candidemia. Presence of central venous catheter and diabetes were statistically significant risk factors for development of candidemia by NAC. Resistance to fluconazole was 36%, resistance to voriconazole was 20%, resistance to 5-flucytosine was 4%, and resistance to amphotericin-B was 7%. C. auris isolates were more resistant than other NAC spp. We detected no resistance among the echinocandins.

Conclusions:

The emergence of highly resistant isolates like C. auris emphasizes the need for constant monitoring of candidemia cases for species identification and routine antifungal susceptibility so that appropriate measures can be taken to reduce the related morbidity and mortality.

Epidemiology and Antifungal Susceptibility Patterns of Invasive Fungal Infections (IFIs) in India: A Prospective Observational Study

The epidemiology of invasive fungal infections (IFI) is ever evolving. The aim of the present study was to analyze the clinical, microbiological, susceptibility, and outcome data of IFI in Indian patients to identify determinants of infection and 30-day mortality. Proven and probable/putative IFI (defined according to modified European Organization for Research and Treatment of Cancer/Mycoses Study Group and AspICU criteria) from April 2017 to December 2018 were evaluated in a prospective observational study. All recruited patients were antifungal naïve (n = 3300). There were 253 episodes of IFI (7.6%) with 134 (52.9%) proven and 119 (47%) probable/putative infections. There were four major clusters of infection: invasive candidiasis (IC) (n = 53, 20.9%), cryptococcosis (n = 34, 13.4%), invasive aspergillosis (IA) (n = 103, 40.7%), and mucormycosis (n = 62, 24.5%). The significant risk factors were high particulate efficiency air (HEPA) room admission, ICU admission, prolonged exposure to corticosteroids, diabetes mellitus, chronic liver disease (CLD), acquired immunodeficiency syndrome (AIDS), coronary arterial disease (CAD), trauma, and multiorgan involvement (p < 0.5; odds ratio: >1). The all-cause 30-day mortality was 43.4% (n = 110). It varied by fungal group: 52.8% (28/53) in IC, 58.8% (20/34) in cryptococcosis, 39.8% (41/103) in IA, and 33.9% (21/62) in mucormycosis. HEPA room, ICU admission for IC; HEPA rooms, diabetes mellitus for cryptococcosis; hematological malignancies, chronic kidney disease (CKD), sepsis, galactomannan antigen index value ≥1 for IA and nodules; and ground glass opacities on radiology for mucormycosis were significant predictors of death (odds ratio >1). High minimum inhibitory concentration (MIC) values for azoles were observed in C. albicans, C. parapsilosis, C. glabrata, A. fumigatus, A. flavus, R. arrhizus, R. microsporus, and M. circinelloides. For echinocandin, high MIC values were seen in C. tropicalis, C. guillermondii, C. glabrata, and A. fumigatus. This study highlights the shift in epidemiology and also raises concern of high MICs to azoles among our isolates. It warrants regular surveillance, which can provide the local clinically correlated microbiological data to clinicians and which might aid in guiding patient treatment.

A systematic review on distribution and antifungal resistance pattern of Candida species in the Indian population

The emergence of antifungal drug resistance in Candida species has led to increased morbidity and mortality in immunocompromised patients. Understanding species distribution and antifungal drug resistance patterns is an essential step for novel drug development. A systematic review was performed addressing this challenge in India with keywords inclusive of 'Candida', 'Antifungal Drug Resistance', 'Candidemia', 'Candidiasis' and 'India'. A total of 106 studies (January 1978-March 2020) from 20 Indian states were included. Of over 11,429 isolates, Candida albicans was the major species accounting for 37.95% of total isolates followed by C. tropicalis (29.40%), C. glabrata (11.68%) and C. parapsilosis (8.36%). Rates of antifungal resistance were highest in non-albicans Candida (NAC) species - C. haemuloni (47.16%), C. krusei (28.99%), C. lipolytica (28.89%) and C. glabrata (20.69%). Approximately 10.34% isolates of C. albicans were observed to be drug-resistant. Candida species were frequently resistant to certain azoles (ketoconazole-22.2%, miconazole-22.1% and fluconazole-21.8%). In conclusion, the present systematic review illustrates the overall distribution and antifungal resistance pattern of Candida species among the Indian population that could be helpful in the future for the formation of treatment recommendations for the region but also elsewhere.

New and Promising Chemotherapeutics for Emerging Infections Involving Drug-resistant Non-albicans Candida Species

Fungal infections are a veritable public health problem worldwide. The increasing number of patient populations at risk (e.g. transplanted individuals, cancer patients, and HIV-infected people), as well as the use of antifungal agents for prophylaxis in medicine, have favored the emergence of previously rare or newly identified fungal species. Indeed, novel antifungal resistance patterns have been observed, including environmental sources and the emergence of simultaneous resistance to different antifungal classes, especially in Candida spp., which are known for the multidrug-resistance (MDR) profile. In order to circumvent this alarming scenario, the international researchers' community is engaged in discovering new, potent, and promising compounds to be used in a near future to treat resistant fungal infections in hospital settings on a global scale. In this context, many compounds with antifungal action from both natural and synthetic sources are currently under clinical development, including those that target either ergosterol or β(1,3)-D-glucan, presenting clear evidence of pharmacologic/pharmacokinetic advantages over currently available drugs against these two well-known fungal target structures. Among these are the tetrazoles VT-1129, VT-1161, and VT-1598, the echinocandin CD101, and the glucan synthase inhibitor SCY-078. In this review, we compiled the most recent antifungal compounds that are currently in clinical trials of development and described the potential outcomes against emerging and rare Candida species, with a focus on C. auris, C. dubliniensis, C. glabrata, C. guilliermondii, C. haemulonii, and C. rugosa. In addition to possibly overcoming the limitations of currently available antifungals, new investigational chemical agents that can enhance the classic antifungal activity, thereby reversing previously resistant phenotypes, were also highlighted. While novel and increasingly MDR non-albicans Candida species continue to emerge worldwide, novel strategies for rapid identification and treatment are needed to combat these life-threatening opportunistic fungal infections.

Revision of the medically relevant species of the yeast genus Diutina

Diutina (Candida) rugosa is emerging as a causative agent of human infections. Recently some close relatives have been described, that is, D. mesorugosa, D. pseudorugosa, and D. neorugosa, some of which have also been implicated in human infection. Phylogenetic relationships of 24 clinical isolates of the D. rugosa complex are reconstructed using multilocus sequence analysis of five housekeeping genes, supplemented with phenotypic studies of CandiSelect™ 4 Agar and nutritional physiology. Diutina mesorugosa could not meaningfully be distinguished from D. rugosa and is regarded as a synonym. Diutina neorugosa and D. pseudorugosa represent separate, distantly related species within the genus Diutina, but have as yet not been encountered in clinical settings.

In vitro virulence determinants, comparative pathogenicity of Diutina (Candida) mesorugosa clinical isolates and literature review of the D. rugosa complex

Opportunistic mycoses by yeasts have increased considerably in the last three decades. Although Candida albicans is considered one of the most important causes of nosocomial infections, there is a recent shift to non-albicans Candida species as the most frequently isolated yeasts in particular risk groups. Diutina rugosa (formerly Candida rugosa) is a complex that includes four species: D. rugosa sensu stricto, D. neorugosa, D. pseudorugosa, and D. mesorugosa, and they are estimated to represent 0.2% of all Candida clinical isolates. In this study, we analyze nine clinical isolates of D. mesorugosa with focus on the virulence determinants and pathogenicity of the species by means of a Galleria mellonella survival model. Overall, we detected very strong aspartyl-protease and esterase activities. In contrast, both DNase and hemolysin activities were evident in only two of the isolates. None of the isolates was positive for phospholipase activity. All isolates studied were able to form biofilm after 72 h of incubation in a robust manner when compared with the C. albicans strain used as control. Susceptibility testing showed minimum inhibitory concentrations (MICs) ≤1 µg/mL for amphotericin B in all isolates tested. Eight out of nine of the isolates had MICs ≤2 µg/mL for fluconazole. All isolates were resistant to both anidulafungin and caspofungin (MICs ≥1 µg/mL). We found a significant difference (P < 0.0001) amongst the survival curves for the different D. mesorugosa isolates in the Galleria mellonella survival model. Strains HPM309 and H259 produced an acute infection and exhibited the highest virulence, whereas the D. mesorugosa isolates 99-480 and DM17 proved to be the less virulent strains.

Susceptibility profile of Candida rugosa (Diutina rugosa) against antifungals and compounds of essential oils

Candida rugosa (recently reclassified Diutina rugosa) is an emerging pathogen affecting humans and animals. Candida resistance to existing drugs is an important factor to be monitored, as well as the need of researching alternatives to conventional antifungals. Here, we evaluated the in vitro effects of some antifungals and major components of essential oils by the broth microdilution method (CLSI M27-A3) against fifteen C. rugosa strains from animals isolated and molecular identificated. The results showed MIC₉₀ of: 0.125μg/mL to ketoconazole and voriconazole, 0.25μg/mL to micafungin, 0.5μg/mL to anidulafungin, 1μg/mL to caspofungin, 2μg/mL to amphotericin B, itraconazole and flucytosin, 8μg/mL to fluconazole, 16μg/mL to nystatin and >128μg/mL to terbinafine. The compounds carvacrol (MIC₉₀ 320μg/mL), thimol (MIC₉₀ 320μg/mL) and cinnamaldehyde (MIC₉₀ 160μg/mL) demonstrated antifungal activity against the samples tested.

Epidemiology and antifungal susceptibility of Candida species in a tertiary care hospital, Kolkata, India

Background and Purpose:

The incidence of fungal infection as well as candidemia has increased significantly, contributing to morbidity and mortality in the developed countries. The alarming increase in infections with multidrug resistant bacteria is due to overuse of a broad spectrum antimicrobials, which leads to over growth of Candida spp.; thus, enhancing its opportunity to cause the disease. A shift has been observed in the relative frequency of each Candida spp. Antifungal agents available for the treatment of systemic and invasive candidiasis are restricted to polyenes, allylamines, azoles, and the recent echinocandin class of molecules. In the past few decades, the incidence of resistance to antifungal treatment of Candida spp. has increased rapidly, which is of serious concern for healthcare professionals. Studies on prevalence of infections and antifungal susceptibility testing can help with deciding on clinical strategies to manage this problem. Herein, we aimed to identify the epidemiology of Candida spp. among blood culture isolates and to investigate the susceptibility pattern of these species to antifungal agents.

Materials and Methods:

Candida spp. were isolated from blood cultures from 70 patients in a tertiary care hospital, Kolkata, India. The growth of Candida spp. on sabouraud dextrose agar was confirmed by Gram staining, where gram-positive budding fungal cells were observed. The species identification as well as antifungal susceptibility testing were performed with VITEK 2 compact automated system using VITEK-2 cards for identification of yeast and yeast-like organisms) ID-YST card). Antifungal susceptibility testing was carried out with VITEK 2 fungal susceptibility card (AST-YS07 kit).

Results:

Out of 70 samples, Candidaalbicans were isolated from 34 (%48.57) samples. The remaining 36 (%51.43) were non-albicans Candida ) NAC). Out of 34 C. Albicans, antifungal susceptiblity was detected in 28 isolates, all of which were sensitive to fluconazole (FLC .( Resistance to amphotericine B) AMP), flucytosine (5FC), voriconazole (VRC), and itraconazole (ITC) was observed in, %44.12 , %52.94 , %8.82 and %17.65 of the cases, respectively. For other Candida spp. (other than C. Albicans ,( antifungal susceptibility was evaluated for 36 isolates, among which resistance to AMP, FLC , 5FC, VRC , and ITC was found in, %30.56 , %61.11 , %33.33 , %19.44 and %38.89 cases, respectively.

Conclusion:

Species-level identification of Candida and their antifungal sensitivity testing should to be performed to achieve better clinical result and to select an appropriate and effective antifungal therapy. High resistance to antifungal agents is an alarming sign to the healthcare professionals.

Invasive candidiasis in non neutropenic critically ill - need for region-specific management guidelines

Use of antifungal agents has increased over past few decades. A number of risk factors such as immunosuppression, broad spectrum antibiotics, dialysis, pancreatitis, surgery, etc., have been linked with the increased risk of invasive candidiasis. Though there are various guidelines available for the use of antifungal therapy, local/regional epidemiology plays an important role in determining the appropriate choice of agent in situations where the offending organism is not known (i.e. empirical, prophylactic or preemptive therapy). Developing countries like India need to generate their own epidemiological data to facilitate appropriate use of antifungal therapy. In this article, the authors have highlighted the need for region-specific policies/guidelines for treatment of invasive candidiasis. Currently available Indian literature on candidemia epidemiology has also been summarized here.

Surveillance for infectious complications in pediatric acute liver failure - a prospective study

OBJECTIVE

To prospectively evaluate infectious complications (IC) in pediatric acute liver failure (PALF) by employing surveillance cultures.

METHODS

From 2011 to 2013, children with PALF in a tertiary care centre received a standard protocolised management. Prophylactic parenteral antibiotics were used without antifungals. Surveillance cultures of blood, urine, ascites and tracheal aspirates were sent. Biochemical and clinical parameters and outcomes were compared between children with and without IC.

RESULTS

Of the 29 children with PALF admitted during the study period (median age 36 mo, range 12-90 mo), 13.8 % had blood stream infections (BSI) at admission. Organisms were isolated in 8.8 % (12/136) of the blood cultures, 13.7 % (11/80) of the urine cultures, 30.8 % (8/26) of the tracheal aspirates and 7.1 % (1/14) of the ascitic fluid cultures. Gram negative bacteriae (n = 17) were the commonest, followed by fungi (n = 13) and gram positive bacteriae (n = 2). Klebsiella pneumoniae and Candida nonalbicans group were the commonest bacteria and fungi respectively. After admission, fungal BSI and urinary tract infections were diagnosed at a median time of 4 d (range 3-8 d) and 3.5 d (range 3-6 d) respectively. ICs were not associated with other complications and increased mortality but with longer hospital and pediatric intensive care unit (PICU) stay.

CONCLUSIONS

In this study BSI was a common finding at admission in PALF. Inspite of prophylactic antibiotics, break through gram negative bacterial and fungal ICs were common. Empirical treatment of IC should include broad spectrum antibiotics. Fungal IC occurred beyond 48 h. Prophylactic antifungals at admission may be considered to decrease their frequency. IC prolongs PICU and hospital stay.

The epidemiological profile of candidemia at an Indian trauma care center

Purpose:

Candida spp. is a common cause of bloodstream infections. Candidemia is a potentially fatal infection that needs urgent intervention to salvage the patients. Trauma patients are relatively young individuals with very few comorbidities, and the epidemiology of candidemia is relatively unknown in this vulnerable and growing population. In this study, we report the epidemiology of candidemia in a tertiary care Trauma Center of India.

Materials and Methods:

The study was conducted from January 2009 to July 2012. All patients from whose blood samples a Candida spp. was recovered were included in this study. A detailed history and follow up of the patients was done. The isolates of Candida were identified to the species level. The speciation was done by conventional methods, including morphology on Corn Meal Agar, color development on Triphenyl Tetrazolium Chloride Agar and CHROMagar, and germ tube tests. The VITEK 2 YST ID colorometric card, a fully automated identification system was also used. Antifungal susceptibility was performed using the VITEK 2 system.

Results:

A total of 212 isolates of the Candida species were recovered from blood samples of 157 patients over the study period. Candida tropicalis, 82 (39%), was the most common, followed by C. parapsilosis, 43 (20%), C. albicans, 29 (14%), C. glabrata, 24 (11%), C. rugosa, 20 (9%), C. hemulonii,; 6 (3%), C. guilliermondii, 4 (2%), C. famata, 3 (1.5%), and C. lusitaniae 1 (0.5%). Out of all the candidemia patients, 68 (43%) had a fatal outcome. Fluconazole and Amphotericin B resistance was seen in seven (3.3%) and seven (3.3%) of the isolates, respectively.

Conclusion:

Candidemia is a significant cause of mortality in trauma patients in our center, with C. tropicalis and C. parapsilosis being the predominant pathogens. Resistance to antifungal drugs is a matter of concern. Better hospital infection control practices and good antibiotic stewardship policies could possibly help in reducing the morbidity and mortality associated with candidemia.

Candidaemia observed at a university hospital in Milan (northern Italy) and review of published studies from 2010 to 2014

BACKGROUND

Candida species represent the fourth leading cause of nosocomial bloodstream infections (BSI) worldwide. However, candidaemia rates and species involved vary geographically.

OBJECTIVES

To evaluate the epidemiological pattern, risk factors for mortality and antifungal therapy of Candida BSI over a 5-year period (2008-2012) in a university hospital in northern Italy together with a review of the recent literature concerning candidaemia.

METHODS

A retrospective cohort study cross-linked with microbiology database was performed.

RESULTS

A total of 89 Candida BSI were identified in 42 males (47 %) and 47 females (52.8 %). The median age was 69 years (interquartile range 55-78) with 61.8 % of patients being older than 65 years. Considering all hospitalized patients, the overall incidence rate of candidaemia increased significantly from 2008 to 2012 (from 0.4 to 1.68 episodes per 10,000 patient/days) (p = 0.0001) with a mean linear increase in 5 new cases per year. Candida albicans was the predominant species isolated (64 %) followed by C. glabrata (19.1 %). The latter species was observed with significantly higher frequency in Internal Medicine and Intensive Care Units (ICU). In-hospital crude mortality was 41.6 %.

CONCLUSIONS

Candidaemia is an increasing BSI in our university hospital, in accordance with that observed in northern Italy, and it is still associated with high in-hospital crude mortality.

Systematic review and new insights into the molecular characterization of the Candida rugosa species complex

Recently, Candida rugosa was characterized as a species complex comprising four taxa: C. rugosa sensu stricto, Candida pseudorugosa, Candida neorugosa and Candida mesorugosa. Although considered relatively rare, several clusters of candidemia due to C. rugosa complex had been reported presenting mortality rates close to 70%. In this work we discuss the systematization, phenotyping and molecular methods based on internal transcribed spacer region (ITS) sequencing and proteomic analyses for species identification, as well as clinical aspects of the C. rugosa complex. We performed a Bayesian phylogenetic analysis using 72 ITS sequences representative of C. rugosa complex isolates and related species within the genus. Biochemical, morphological and MALDI-TOF MS analyses were processed with C. rugosa complex type strains and related species isolates. We described that the phylogeny showed four distinct clades inferred with high posterior probabilities, corresponding to the four species within the C. rugosa complex, excluding C. pararugosa. Biochemical and morphological aspects distinguished only C. rugosa sensu stricto but were not sufficient to accurately identify species within the rest of the complex. Protein spectrum profiles differentiated all reference strains from different species analyzed. To our knowledge, we presented the first phylogenetic analysis using a large collection of ITS sequences as well as proteomic profiles generated from isolates of the C. rugosa complex and related species that can enlighten systematics, diagnostics and clinical research fields.

Molecular identification and antifungal susceptibility testing of clinical isolates of the Candida rugosa species complex and proposal of the new species Candida neorugosa

Candida rugosa is a poorly known fungal species occasionally involved in human infections. A molecular analysis of the sequences of the D1/D2 domains and the internal transcribed spacer (ITS) region of the ribosomal genes of 24 clinical isolates phenotypically identified as C. rugosa demonstrated that only 10 (41.6%) isolates belonged to that species. The other isolates were identified as Candida pararugosa (41.6%) and Candida pseudorugosa (8.3%). The remaining two isolates, from human and equine infections, respectively, were clearly different from the others and represent a new species proposed here as Candida neorugosa. The closest species by D1/D2 sequences was the type strain of C. rugosa, with only 92.3% similarity. C. neorugosa can also be differentiated from all other species of the C. rugosa complex by phenotypic features. The eight antifungal drugs tested showed high in vitro activity against the 24 isolates included in the study.

First case report of bloodstream infection due to a Candida species closely related to the novel species Candida pseudorugosa

Candida pseudorugosa is a novel species closely related to Candida rugosa for which only one case has been reported. We report the first case of a bloodstream infection in humans caused by a Candida sp. closely related to C. pseudorugosa. We contribute evidence to show this organism as a potential human pathogen that may be misidentified by conventional methods, also pointing out its lower sensitivity to azoles and other antifungal agents.