Antifungal susceptibility of 1000 Candida bloodstream isolates to 5 antifungal drugs: results of a multicenter study conducted in São Paulo, Brazil, 1995–2003

Meyerozyma guilliermondii species complex: review of current epidemiology, antifungal resistance, and mechanisms

Meyerozyma guilliermondii has been accepted as a complex composed of Meyerozyma guilliermondii, Meyerozyma carpophila, and Meyerozyma caribbica. M. guilliermondii is a saprophyte detected on human mucosa and skin. It can lead to serious infections in patients with risk factors like chemotherapy, immunodeficiency, gastrointestinal or cardiovascular surgery, and oncology disorders. Most deaths related to M. guilliermondii infections occur in individuals with malignancy. In recent decades, incidence of M. guilliermondii infections is increased. Sensitivity of this microorganism to conventional antifungals (e.g., amphotericin B, fluconazole, micafungin and anidulafungin) was reduced. Prophylactic and empirical uses of these drugs are linked to elevated minimal inhibitory concentrations (MICs) of M. guilliermondii. Drug resistance has concerned many researchers across the world. They are attempting to discover appropriate solution to combat this challenge. This study reviews the most important mechanisms of resistance to antifungals developed by in M. guilliermondii species complex.

Overview on the Infections Related to Rare Candida species

Atypical Candida spp. infections are rising, mostly due to the increasing numbers of immunocompromised patients. The most common Candida spp. is still Candida albicans; however, in the last decades, there has been an increase in non-Candida albicans Candida species infections (e.g., Candida glabrata, Candida parapsilosis, and Candida tropicalis). Furthermore, in the last 10 years, the reports on uncommon yeasts, such as Candida lusitaniae, Candida intermedia, or Candida norvegensis, have also worryingly increased. This review summarizes the information, mostly related to the last decade, regarding the infections, diagnosis, treatment, and resistance of these uncommon Candida species. In general, there has been an increase in the number of articles associated with the incidence of these species. Additionally, in several cases, there was a suggestive antifungal resistance, particularly with azoles, which is troublesome for therapeutic success.

Antifungal susceptibility profile of Candida clinical isolates from 22 hospitals of São Paulo State, Brazil

This study aimed to evaluate the frequency of cryptic Candida species from candidemia cases in 22 public hospitals in São Paulo State, Brazil, and their antifungal susceptibility profiles. During 2017 and 2018, 144 isolates were molecularly identified as 14 species; C. parapsilosis (32.6%), C. albicans (27.7%), C. tropicalis (14.6%), C. glabrata (9.7%), C. krusei (2.8%), C. orthopsilosis (2.8%), C. haemulonii var. vulnera (2.1%), C. haemulonii (1.4%), C. metapsilosis (1.4%), C. dubliniensis (1.4%), C. guilliermondii (1.4%), C. duobushaemulonii (0.7%), C. kefyr (0.7%), and C. pelliculosa (0.7%). Poor susceptibility to fluconazole was identified in 6.4% of C. parapsilosis isolates (0.12 to >64 µg/mL), 50% of C. guilliermondii (64 µg/mL), 66.6% of C. haemulonii var. vulnera (16-32 µg/mL), and C. duobushaemulonii strain (MIC 64 µg/mL). Our results corroborated the emergence of C. glabrata in Brazilian cases of candidemia as previously reported. Importantly, we observed a large proportion of non-wild type C. glabrata isolates to voriconazole (28.6%; <0.015 to 4 µg/mL) all of which were also resistant to fluconazole (28.6%). Of note, C. haemulonii, a multidrug resistant species, has emerged in the Southeast region of Brazil. Our findings suggested a possible epidemiologic change in the region with an increase in fluconazole-resistant species causing candidemia. We stress the relevance of routine accurate identification to properly manage therapy and monitor epidemiologic trends.

Clinical and epidemiological aspects of Candidemia in eight medical centers in the state of Parana, Brazil: Parana Candidemia Network

Objectives

Candida spp. has been reported as one of the common agents of nosocomial bloodstream infections and is associated with a high mortality. Therefore, this study evaluated the clinical findings, local epidemiology, and microbiological aspects of candidemia in eight tertiary medical centers in the state of Parana, South of Brazil.

Methods

In this study, we reported 100 episodes of candidemia in patients admitted to eight different hospitals in five cities of the state of Parana, Brazil, using data collected locally (2016 and 2017) and tabulated online.

Results

The incidence was found to be 2.7 / 1000 patients / day and 1.2 / 1000 admissions. C. albicans was responsible for 49% of all candidemia episodes. Cancer and surgery were the two most common underlying conditions associated with candidemia. The mortality rate within 30 days was 48%, and removal of the central venous catheter (p = 0.029) as well as empirical or prophylactic exposure to antifungals were both related to improved survival (p = 0.033).

Conclusions

This study highlights the high burden and mortality rates of candidemia in hospitals from Parana as well as the need to enhance antifungal stewardship program in the enrolled medical centers.

Opportunistic invasive fungal disease in patients with type 2 diabetes mellitus from Southern China: Clinical features and associated factors

AIMS/INTRODUCTION

A retrospective study was carried out to investigate the clinical characteristics and associated factors for invasive fungal disease in patients with type 2 diabetes mellitus.

MATERIALS AND METHODS

Demographic and clinical data were recorded. Associated factors were analyzed by logistic regression analysis.

RESULTS

Invasive fungal disease was diagnosed in 120 patients with type 2 diabetes mellitus (prevalence, 0.4%). Yeast infection (56/120, 46.7%), including candidiasis (31/56, 55.4%) and cryptococcosis (25/56, 44.6%), was the most common. The urinary tract was mainly involved in candidiasis (12/31, 38.7%). More than half of the cryptococcosis (16/25, 64.0%) presented as pneumonia. Mold infection accounted for 40.8% of the cases, and predominantly involved the lung (34/49, 69.4%). A total of 15 (12.5%) patients had mixed fungal infection. Candida albicans (24/111, 21.6%), Cryptococcus neoformans (19/111, 17.1%) and Aspergillus fumigatus (14/111, 12.6%) were the leading agents. Co-infection occurred in 58 (48.3%) patients, mainly presenting as pneumonia caused by Gram-negative bacteria. The inpatient mortality rate of invasive fungal disease was 23.3% (28/120). Glycated hemoglobin levels were higher in non-survivors than survivors (8.8 ± 2.5 vs 7.7 ± 2.1%, P = 0.02). Anemia (adjusted odds ratio, 3.50, 95% confidence interval 1.95-6.27, P < 0.001), hypoalbuminemia (adjusted odds ratio, 5.42, 95% confidence interval 3.14-9.36, P < 0.001) and elevated serum creatinine (adjusted odds ratio, 2.08, 95% confidence interval 1.07-4.04, P = 0.03) were associated with invasive fungal disease in type 2 diabetes mellitus patients.

CONCLUSIONS

Invasive fungal disease is a life-threatening complication in type 2 diabetes mellitus patients. C. a albicans, C. neoformans, and A. fumigatus are the leading agents. Prolonged hyperglycemia results in unfavorable outcomes. Correction of anemia and hypoalbuminemia might improve prognosis.

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.

Revisiting Species Distribution and Antifungal Susceptibility of Candida Bloodstream Isolates from Latin American Medical Centers

The epidemiology of candidemia varies geographically, and there is still scarce data on the epidemiology of candidemia in Latin America (LA). After extensive revision of medical literature, we found reliable and robust information on the microbiological aspects of candidemia in patients from 11 out of 21 medical centers from LA countries and 1 out of 20 from Caribbean countries/territories. Based on 40 papers attending our search strategy, we noted that C. albicans remains the most common species causing candidemia in our region, followed by C. parapsilosis and C. tropicalis. In Argentina, Brazil, and Colombia, a trend towards an increase in frequency of C. glabrata candidemia was observed. Although resistance rates to fluconazole is under 3%, there was a slight increase in the resistance rates to C. albicans, C. parapsilosis and C. tropicalis isolates. Echinocandin resistance has been reported in a few surveys, but no single study confirmed the resistant phenotype reported by using molecular methods. We highlight the importance of conducting continuous surveillance studies to identify new trends in terms of species distribution of Candida and antifungal resistance related to episodes of candidemia in LA. This information is critical for helping clinicians to prevent and control Candida bloodstream infections in their medical centers.

Thyroid abnormalities in term infants with fungal sepsis

Objective:

To describe thyroid alterations in term newborns (TNB) with fungal sepsis during NICU hospitalization.

Method:

The study included six TNB that during the clinical and laboratory manifestations of sepsis with positive cultures for fungus showed changes in thyroid hormones, called low T3 syndrome and low T3-T4 syndrome. TNB that could present hormonal changes caused by disease as those born to mothers with thyroid disease, or who had perinatal asphyxia and major surgeries were excluded.

Results:

Of six TNB with fungal sepsis, five had positive culture for Candida albicans and one had positive culture for Candida tropicalis. Low T3 syndrome was observed in two TNB (50%), while T3-T4 syndrome was observed in other two (100%). The four children progressed to septic shock.

Conclusion:

Fungal sepsis is becoming more common among newborns admitted to NICU. Thyroid insufficiency could be a marker of disease severity with possible need for hormone supplementation.

Antifungal Therapy: New Advances in the Understanding and Treatment of Mycosis

The high rates of morbidity and mortality caused by fungal infections are associated with the current limited antifungal arsenal and the high toxicity of the compounds. Additionally, identifying novel drug targets is challenging because there are many similarities between fungal and human cells. The most common antifungal targets include fungal RNA synthesis and cell wall and membrane components, though new antifungal targets are being investigated. Nonetheless, fungi have developed resistance mechanisms, such as overexpression of efflux pump proteins and biofilm formation, emphasizing the importance of understanding these mechanisms. To address these problems, different approaches to preventing and treating fungal diseases are described in this review, with a focus on the resistance mechanisms of fungi, with the goal of developing efficient strategies to overcoming and preventing resistance as well as new advances in antifungal therapy. Due to the limited antifungal arsenal, researchers have sought to improve treatment via different approaches, and the synergistic effect obtained by the combination of antifungals contributes to reducing toxicity and could be an alternative for treatment. Another important issue is the development of new formulations for antifungal agents, and interest in nanoparticles as new types of carriers of antifungal drugs has increased. In addition, modifications to the chemical structures of traditional antifungals have improved their activity and pharmacokinetic parameters. Moreover, a different approach to preventing and treating fungal diseases is immunotherapy, which involves different mechanisms, such as vaccines, activation of the immune response and inducing the production of host antimicrobial molecules. Finally, the use of a mini-host has been encouraging for in vivo testing because these animal models demonstrate a good correlation with the mammalian model; they also increase the speediness of as well as facilitate the preliminary testing of new antifungal agents. In general, many years are required from discovery of a new antifungal to clinical use. However, the development of new antifungal strategies will reduce the therapeutic time and/or increase the quality of life of patients.

Propolis: a potential natural product to fight Candida species infections

AIM

To evaluate the effect of propolis against Candida species planktonic cells and its counterpart's biofilms.

MATERIALS & METHODS

The MIC values, time-kill curves and filamentation form inhibition were determined in Candida planktonic cells. The effect of propolis on Candida biofilms was assessed through quantification of CFUs.

RESULTS

MIC values, ranging from 220 to 880 µg/ml, demonstrated higher efficiency on C. albicans and C. parapsilosis than on C. tropicalis cells. In addition, propolis was able to prevent Candida species biofilm's formation and eradicate their mature biofilms, coupled with a significant reduction on C. tropicalis and C. albicans filamentation.

CONCLUSION

Propolis is an inhibitor of Candida virulence factors and represents an innovative alternative to fight candidiasis.

Successful therapy of Candida pulcherrima fungemia in a premature newborn with liposomal amphotericin B and micafungin

New Candida species may cause bloodstream infections challenging current therapeutic approaches because of unpredictable susceptibility and virulence. In the present report, we describe a fungemia case due to Candida pulcherrima in a premature neonate. After full in vitro diagnostic workup, the neonate was successfully treated with liposomal amphotericin B and micafungin achieving rapid fungal eradication from blood.

Candida glabrata among Candida spp. from environmental health practitioners of a Brazilian Hospital

The incidence of the species Candida albicans and non-albicans Candida was evaluated in a Brazilian Tertiary Hospital from the environment and health practitioners. In a 12-month period we had a total positivity of 19.65% of Candida spp. The most recurring non-albicans Candida species was C. glabrata (37.62%), generally considered a species of low virulence, but with a higher mortality rate than C. albicans. Subsequently, C. parapsilosis (25.74%) and C. tropicalis (16.86%) were the second and third most commonly isolated species. Considering the total samples collected from the emergency room and from the inpatient and the pediatric sector, 19.10% were positive for Candida spp., with the predominance of non-albicans Candida species (89.42%). The high percentage of positivity occurred in the hands (24.32%) and the lab coats (21.88%) of the health care assistants. No sample of C. albicans presented a profile of resistance to the drugs. All the non-albicans Candida species presented a decreased susceptibility to miconazole and itraconazole, but they were susceptible to nystatin. Most of the isolates were susceptible to fluconazole and amphotericin B. As expected, a high resistance rate was observed in C. glabrata and C. krusei, which are intrinsically less susceptible to this antifungal agent. The contamination of environmental surfaces by Candida spp. through hand touching may facilitate the occurrence of Candida infections predominantly in immunocompromised patients. In addition to that, the antifungal agents used should be carefully evaluated considering local epidemiologic trends in Candida spp. infections, so that therapeutic choices may be better guided.

FREQUENCY OF Candida SPECIES IN A TERTIARY CARE HOSPITAL IN TRIANGULO MINEIRO, MINAS GERAIS STATE, BRAZIL

Infections by Candida species are a high-impact problem in public health due to their wide incidence in hospitalized patients. The goal of this study was to evaluate frequency, susceptibility to antifungals, and genetic polymorphism of Candida species isolated from clinical specimens of hospitalized patients. The Candida isolates included in this study were obtained from blood cultures, abdominal fluids, and central venous catheters (CVC) of hospitalized patients at the Clinical Hospital of the Federal University of Uberlândia during the period of July 2010 - June 2011. Susceptibility tests were conducted by the broth microdilution method. The RAPD-PCR tests used employed initiator oligonucleotides OPA09, OPB11, and OPE06. Of the 63 Candida isolates, 18 (28.5%) were C. albicans, 20 (31.7%) were C. parapsilosis complex species, 14 (22.2%) C. tropicalis, four (6.4%) C. glabrata, four (6.4%) C. krusei, two (3.3%) C. kefyr, and one (1.6%) C. lusitaniae. In vitro resistance to amphotericin B was observed in 12.7% of isolates. In vitroresistance to azoles was not detected, except for C. krusei. The two primers, OPA09 and OPB11, were able to distinguish different species. Isolates of C. albicans and C. parapsilosis complex species presented six and five clusters, respectively, with the OPA09 marker by RAPD-PCR, showing the genetic variability of the isolates of those species. It was concluded that members of the C. parapsilosis complex were the most frequent species found, and most isolates were susceptible to the antifungals amphotericin B, flucozanole, and itraconazole. High genetic polymorphisms were observed for isolates of C. albicans and C. parapsilosis complex species, mainly with the OPA09 marker.

Study on chemical analysis, antioxidant and in vitro antifungal activities of essential oil from wild Vitex agnus-castus L. seeds growing in area of Argan Tree of Morocco against clinical strains of Candida responsible for nosocomial infections

OBJECTIVE

To study the composition, the antioxidant activity and the in vitro antifungal action anti-Candida species of essential oils extracted from seeds of Vite xagnus-castus L.

MATERIALS AND METHOD

The essential oils were extracted using Clevenger-type apparatus and analyzed by gas chromatography/mass spectrometry (GC/MS). The antioxidant activity was analyzed using the DPPH free radical-scavenging method. Susceptibility tests for Candida albicans (12), C. dubliniensis (1), C. glabrata (3), C. krusei (3), C. parapsilosis (6), C. lusitaniae (1), C. famata (1) and C. tropicalis (3) were expressed as inhibition zone by the disc-diffusion method and as minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) by the broth macrodilution method, compared to amphotricin B and fluconazol as standard drugs.

RESULTS

Major components were: 1,8-cineole (19.61%), sabinene (14.57%), α-pinene (9.76%), β-farnesene (6.04%), β-caryophyllene oxide (5.83%) and β-caryophyllene (5.02%). A low antioxidant activity was found (IC50=1.072mg/ml), but it can be exploited. V. agnus-castus seeds essential oils disosed a 35-58mm zone of inhibition (mean: 49mm) against all 30 isolates tested. In broth macrodilution method, all the tested Candida species were susceptible to the essential oils and this activity was concentration-dependent. MIC values varied from 0.13 to 2.13mg/ml V. agnus-castus seeds essential oils.

CONCLUSION

Results of this study indicated that the oils of plant origin could be used as potential anti-Candida species causative agents of nosocomial infections. These oils exhibited a noticeable antifungal activity against the selected fungi. The natural antifungal substances are inexpensive and have fewer side effects, they may represent alternative therapies for candidiasis.

Prevalence and Fluconazole Susceptibility Profile of Candida spp. Clinical Isolates in a Brazilian Tertiary Hospital in Minas Gerais, Brazil

Candidiasis has become an important concern for clinical practice, especially with the increasing incidence of immunocompromised patients. In this scenario, the development resistance to fluconazole presents a challenge for treating these opportunistic infections. The aim of this study was to evaluate some epidemiology features of Candidainfections in a Brazilian University Hospital using data, previously unavailable. We observed that 44% of the 93 clinical isolates tested, belonged to Candida albicansspecies and 56% belonged to non-Candida albicansspecies (mainly Candida tropicalis and Candida glabrata). Most strains were isolated from urine samples where C. albicans was predominantly detected. 29 strains presented a fluconazole resistance phenotype and of these, 22 were chemosensitised by FK506, a classical inhibitor of ABC transporters related to azoles resistance. These data suggest the probable role of efflux pumps in this resistance phenotype. Our study highlights the need for developing effective control measures for fungal infections, rational use of antifungal drugs and development of new molecules able to abrogate the active transport of antifungals.

Nosocomial candidiasis in Rio de Janeiro State: Distribution and fluconazole susceptibility profile

One hundred and forty-one Candida species isolated from clinical specimens of hospitalized patients in Rio de Janeiro, Brazil, during 2002 to 2007, were analized in order to evaluate the distribution and susceptibility of these species to fluconazole. Candida albicans was the most frequent species (45.4%), followed by C. parapsilosis sensu lato (28.4%), C. tropicalis (14.2%), C. guilliermondii (6.4%), C. famata (2.8%), C. glabrata (1.4%), C. krusei (0.7%) and C. lambica (0.7%). The sources of fungal isolates were blood (47.5%), respiratory tract (17.7%), urinary tract (16.3%), skin and mucous membrane (7.1%), catheter (5.6%), feces (2.1%) and mitral valve tissue (0.7%). The susceptibility test was performed using the methodology of disk-diffusion in agar as recommended in the M44-A2 Document of the Clinical and Laboratory Standards Institute (CLSI). The majority of the clinical isolates (97.2%) was susceptible (S) to fluconazole, although three isolates (2.1%) were susceptible-dose dependent (S-DD) and one of them (0.7%) was resistant (R). The S-DD isolates were C. albicans, C. parapsilosis sensu lato and C. tropicalis. One isolate of C. krusei was resistant to fluconazole. This work documents the high susceptibility to fluconazole by Candida species isolated in Rio de Janeiro, Brazil.

Susceptibility of Candida spp. isolated from blood cultures as evaluated using the M27-A3 and new M27-S4 approved breakpoints

The high mortality rates associated with candidemia episodes and the emergence of resistance to antifungal agents necessitate the monitoring of the susceptibility of fungal isolates to antifungal treatments. The new, recently approved, species-specific clinical breakpoints (SS-CBPs)(M27-S4) for evaluating susceptibility require careful interpretation and comparison with the former proposals made using the M27-A3 breakpoints, both from CLSI. This study evaluated the susceptibility of the different species of Candida that were isolated from candidemias based on these two clinical breakpoints. Four hundred and twenty-two isolates were identified and, among them, C. parapsilosis comprised 46.68%, followed by C. albicans (35.78%), C. tropicalis (9.71%), C. glabrata (3.55%), C. lusitaniae (1.65%), C. guilliermondii (1.65%) and C. krusei (0.94%). In accordance with the M27-A3 criteria, 33 (7.81%) non-susceptible isolates were identified, of which 16 (3.79%) were resistant to antifungal agents. According to SS-CBPs, 80 (18.95%) isolates were non-susceptible, and 10 (2.36%) of these were drug resistant. When the total number of non-susceptible isolates was considered, the new SS-CBPs detected 2.4 times the number of isolates that were detected using the M27-A3 interpretative criteria. In conclusion, the detection of an elevated number of non-susceptible species has highlighted the relevance of evaluating susceptibility tests using new, species-specific clinical breakpoints (SS-CBPs), which could impact the profile of non-susceptible Candida spp. to antifungal agents that require continuous susceptibility monitoring.

Genetic diversity of medically important and emerging Candida species causing invasive infection

BACKGROUND

Genetic variation in the ribosomal DNA (rDNA) internal transcribed spacer (ITS) region has been studied among fungi. However, the numbers of ITS sequence polymorphisms in the various Candida species and their associations with sources of invasive fungal infections remain poorly investigated. Here, we characterized the intraspecific and interspecific ITS diversity of Candida spp. strains collected from patients with bloodstream or oroesophageal candidiasis.

METHODS

We selected cultures of representative medically important species of Candida as well as some rare and emerging pathogens. Identification was performed by micromorphology and by biochemical testing using an ID32C system, as well as by the sequencing of rDNA ITS. The presence of intraspecific ITS polymorphisms was characterized based on haplotype networks, and interspecific diversity was characterized based on Bayesian phylogenetic analysis.

RESULTS

Among 300 Candida strains, we identified 76 C. albicans, 14 C. dubliniensis, 40 C. tropicalis, 47 C. glabrata, 34 C. parapsilosis (sensu stricto), 31 C. orthopsilosis, 3 C. metapsilosis, 21 Meyerozyma guilliermondii (C. guilliermondii), 12 Pichia kudriavzevii (C. krusei), 6 Clavispora lusitaniae (C. lusitaniae), 3 C. intermedia, 6 Wickerhamomyces anomalus (C. pelliculosa), and 2 C. haemulonii strains, and 1 C. duobushaemulonii, 1 Kluyveromyces marxianus (C. kefyr), 1 Meyerozyma caribbica (C. fermentati), 1 Pichia norvegensis (C. norvegensis), and 1 Lodderomyces elongisporus strain. Out of a total of seven isolates with inconsistent ID32C profiles, ITS sequencing identified one C. lusitaniae strain, three C. intermedia strains, two C. haemulonii strains and one C. duobushaemulonii strain. Analysis of ITS variability revealed a greater number of haplotypes among C. albicans, C. tropicalis, C. glabrata and C. lusitaniae, which are predominantly related to endogenous sources of acquisition. Bayesian analysis confirmed the major phylogenetic relationships among the isolates and the molecular identification of the different Candida spp.

CONCLUSIONS

Molecular studies based on ITS sequencing are necessary to identify closely related and emerging species. Polymorphism analysis of the ITS rDNA region demonstrated its utility as a genetic marker for species identification and phylogenetic relationships as well as for drawing inferences concerning the natural history of hematogenous infections caused by medically important and emerging Candida species.

Nosocomial bloodstream Candida infections in a tertiary-care hospital in South Brazil: a 4-year survey

The aims of this study were to evaluate the epidemiology of nosocomial candidemia in a tertiary hospital in South Brazil and the in vitro antifungal susceptibility of isolates. Blood strains from 108 patients were identified by PCR-based method. Some 30.5 % of candidemia were caused by Candida tropicalis, 28.7 % were due to Candida albicans, 24.1 % with Candida parapsilosis sensu stricto, 8.3 % with Candida glabrata sensu lato, 1.8 % involved Candida krusei and 6.6 % with other species. Candidemia was more common in intensive care unit settings (66 %). In vitro susceptibility to antifungal drugs was determined by a microdilution method; and new species-specific clinical breakpoints for fluconazole and voriconazole were applied. Overall susceptibility rates were 100 % for itraconazole, 91 % for fluconazole, 98 % for voriconazole and 99 % for amphotericin B. Fluconazole resistance was mostly among C. parapsilosis sensu stricto isolates (26.9 %). Most of the findings reported here agreed with epidemiological features common to other tertiary hospitals in Brazil; but also revealed some peculiarities, such as a high frequency of C. tropicalis associated with candidemia. Besides, high rate of fluconazole resistance among C. parapsilosis stricto sensu isolates was obtained when applying the new species-specific clinical breakpoints.

Use of the VITEK 2 system to identify and test the antifungal susceptibility of clinically relevant yeast species

Eleven quality control isolates (Candida albicans ATCC 64548, C. tropicalis ATCC 200956, C. glabrata ATCC 90030, C. lusitaniae ATCC 200951, C. parapsilosis ATCC 22019, C. krusei ATCC 6258, C. dubliniensis ATCC 6330, Saccharomyces cerevisiae ATCC 9763, Cryptococcus neoformans ATCC 90012, C. gattii FIOCRUZ-CPF 60, and Trichosporon mucoides ATCC 204094) and 32 bloodstream isolates, including C. albicans, C. tropicalis, C. parapsilosis, C. glabrata, C. krusei, C. guilliermondii, C. pelliculosa (Pichia anomala), C. haemulonii, C. lusitaniae, and C. kefyr were identified at the species level by the VITEK 2 system. A set of clinical isolates (32 total) were used as challenge strains to evaluate the ability of the VITEK 2 system to determine the antifungal susceptibility of yeasts compared with the CLSI and EUCAST BMD reference standards. The VITEK 2 system correctly identified 100% of the challenge strains. The identification of yeast species and the evaluation of their susceptibility profiles were performed in an automated manner by the VITEK 2 system after approximately 15 h of growth for most species of Candida. The VITEK 2 system ensures that each test is performed in a standardized manner and provides quantitative MIC results that are reproducible and accurate when compared with the BMD reference methods. This system was able to determine the MICs of amphotericin B, flucytosine, voriconazole, and fluconazole in 15 h or less for the most common clinically relevant Candida species. In addition, the VITEK 2 system could reliably identify resistance to flucytosine, voriconazole, and fluconazole and exhibits excellent quantitative and qualitative agreement with the CLSI or EUCAST broth microdilution reference methods.

[Recommendations for the management of candidemia in adults in Latin America. Grupo Proyecto Épico]

Candidemia is one of the most frequent opportunistic mycoses worldwide. Limited epidemiological studies in Latin America indicate that incidence rates are higher in this region than in the Northern Hemisphere. Diagnosis is often made late in the infection, affecting the initiation of antifungal therapy. A more scientific approach, based on specific parameters, for diagnosis and management of candidemia in Latin America is warranted. 'Recommendations for the diagnosis and management of candidemia' are a series of manuscripts that have been developed by members of the Latin America Invasive Mycosis Network. They aim to provide a set of best-evidence recommendations for the diagnosis and management of candidemia. This publication, 'Recommendations for the management of candidemia in adults in Latin America', was written to provide guidance to healthcare professionals on the management of adults who have, or who are at risk of, candidemia. Computerized searches of existing literature were performed by PubMed. The data were extensively reviewed and analyzed by members of the group. The group also met on two occasions to pose questions, discuss conflicting views, and deliberate on a series of management recommendations. 'Recommendations for the management of candidemia in adults in Latin America' includes prophylaxis, empirical therapy, therapy for proven candidemia, patient work-up following diagnosis of candidemia, duration of candidemia treatment, and central venous catheter management in patients with candidemia. This manuscript is the second of this series that deals with diagnosis and treatment of invasive candidiasis. Other publications in this series include: 'Recommendations for the diagnosis of candidemia in Latin America', 'Recommendations for the management of candidemia in children in Latin America', and 'Recommendations for the management of candidemia in neonates in Latin America'.

[Susceptibility of Candida albicans blood isolates to 3 antifungal drugs: retrospective study in Rio Grande do Sul, Brazil, 1999-2009]

BACKGROUND

Candidiasis is one of the most important among recurrent invasive yeast infections in patients, thus antifungal treatment becomes a challenge.

AIMS

The aim of this study was to evaluate the in vitro activity of clinical Candida albicans isolates from blood cultures to fluconazole, amphotericin B and anidulafungin, in a hospital from Rio Grande do Sul, Brazil.

METHODS

The susceptibility of 153 isolates to the 3 drugs mentioned was tested according to Clinical and Laboratory Standars Institute. Minimal inhibitory and fungicidal concentrations (MIC, MFC, respectively) of each drug were determined, as well as the epidemiological cutoff value (ECV).

RESULTS

All of the isolates were susceptible to anidulafungin, MIC and MFC ≤ 1 μg/ml; however, when compared with ECV, 3% of the isolates exhibited higher values against fluconazole, 96% were susceptible, 3% susceptible dose-dependent, and 1% resistant. Also, it was observed that 21% of the isolates exhibited higher values than ECV. One isolate was resistant to amphotericin B; the other ones, susceptible, based on the MFC; furthermore, 1.5% of the isolates exhibited higher values.

CONCLUSIONS

C. albicans isolates exhibited more susceptibility to anidulafungin, and 90% of them (MIC90) exhibited the lowest values against amphotericin B. Based on ECV and Pfaller classification, isolates could be resistant to fluconazole, demonstrating the importance of the combination of these parameters.

Multilocus sequence typing of Candida tropicalis shows the presence of different clonal clusters and fluconazole susceptibility profiles in sequential isolates from candidemia patients in Sao Paulo, Brazil

The profiles of 61 Candida tropicalis isolates from 43 patients (28 adults and 15 children) diagnosed with candidemia at two teaching hospitals in São Paulo, Brazil, were characterized by multilocus sequence typing (MLST). For the 14 patients who had bloodstream infections, 32 isolates were serially collected from their blood and/or catheters. Thirty-nine diploid sequence types (DSTs) were differentiated. According to the C. tropicalis MLST database (http://pubmlst.org/ctropicalis/), 36 DSTs and 23 genotypes identified from the 61 isolates had not previously been described. This report represents the first study to characterize sequential isolates of C. tropicalis from candidemia cases in South America. Microvariation in a single gene was found in the sequential isolates from 7 patients. The main polymorphisms occurred in the alleles of the XYR1 gene, specifically at nucleotide positions 215, 242, and 344. Macrovariation in six gene fragments was detected in the isolates from 3 patients. eBURST analysis added two new groups to this study (groups 6 and 18). Additionally, susceptibility tests indicate that 3 isolates were resistant to fluconazole. No correlation was found between the DSTs and susceptibility to fluconazole and/or selective antifungal pressure. Two patients were sequentially infected with resistant and susceptible strains. MLST is an important tool for studying the genetic diversity of multiple/sequential isolates of patients with candidemia, allowing the comparison of our data with those from other regions of the world, as well as allowing an analysis of the genetic relationship among several clones in sequential isolates from the same or different candidemia patient sites (blood or catheter).

Candida spp. isolated from inpatients, the environment, and health practitioners in the Pediatric Unit at the Universitary Hospital of the Jundiaí Medical College, State of São Paulo, Brazil

INTRODUCTION

This study aimed to isolate and identify Candida spp. from the environment, health practitioners, and patients with the presumptive diagnosis of candidiasis in the Pediatric Unit at the Universitary Hospital of the Jundiaí Medical College, to verify the production of enzymes regarded as virulence factors, and to determine how susceptible the isolated samples from patients with candidiasis are to antifungal agents.

METHODS

Between March and November of 2008 a total of 283 samples were taken randomly from the environment and from the hands of health staff, and samples of all the suspected cases of Candida spp. hospital-acquired infection were collected and selected by the Infection Control Committee. The material was processed and the yeast genus Candida was isolated and identified by physiological, microscopic, and macroscopic attributes.

RESULTS

The incidence of Candida spp. in the environment and employees was 19.2%. The most frequent species were C. parapsilosis and C. tropicalis among the workers, C. guilliermondii and C. tropicalis in the air, C. lusitanae on the contact surfaces, and C. tropicalis and C. guilliermondii in the climate control equipment. The college hospital had 320 admissions, of which 13 (4%) presented Candida spp. infections; three of them died, two being victims of a C. tropicalis infection and the remaining one of C. albicans. All the Candida spp. in the isolates evidenced sensitivity to amphotericin B, nystatin, and fluconazole.

CONCLUSIONS

The increase in the rate of hospital-acquired infections caused by Candida spp. indicates the need to take larger measures regarding recurrent control of the environment.

Species distribution and in vitro fluconazole susceptibility of clinical Candida isolates in a Brazilian tertiary-care hospital over a 3-year period

INTRODUCTION

In this study, we aimed at identifying Candida isolates obtained from blood, urine, tracheal secretion, and nail/skin lesions from cases attended at the Hospital Universitário de Londrina over a 3-year period and at evaluating fluconazole susceptibilities of the isolates.

METHODS

Candida isolates were identified by polymerase chain reaction (PCR) using species-specific forward primers. The in vitro fluconazole susceptibility test was performed according to EUCAST-AFST reference procedure.

RESULTS

Isolates were obtained from urine (53.4%), blood cultures (19.2%), tracheal secretion (17.8%), and nail/skin lesions (9.6%). When urine samples were considered, prevalence was similar in women (45.5%) and in men (54.5%) and was high in the age group >61 years than that in younger ones. For blood samples, prevalence was high in neonates (35%) and advanced ages (22.5%). For nail and skin samples, prevalence was higher in women (71.4%) than in men (28.6%). Candida albicans was the most frequently isolated in the hospital, but Candida species other than C. albicans accounted for 64% of isolates, including predominantly Candida tropicalis (33.2%) and Candida parapsilosis (19.2%). The trend for non-albicans Candida as the predominant species was noted from all clinical specimens, except from urine samples. All Candida isolates were considered susceptible in vitro to fluconazole with the exception of isolates belonging to the intrinsically less-susceptible species C. glabrata.

CONCLUSIONS

Non-albicans Candida species were more frequently isolated in the hospital. Fluconazole resistance was a rare finding in our study.

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

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

In vitro susceptibility of a large collection of Candida Strains against fluconazole and voriconazole by using the CLSI disk diffusion assay

We evaluated all Candida spp. isolates obtained from patients admitted to two tertiary care hospitals between 1999 and 2003 in the city of São Paulo, Brazil. The in vitro activities of fluconazole (FCZ) and voriconazole were determined by the agar disk diffusion test using the Clinical and Laboratory Standards Institute M44-A guidelines. The inhibition zone diameters were read and interpreted automatically by the BIOMIC(®) image-analysis plate reader system. We tested a total of 4,625 strains, including 2,393 strains of C. albicans (51.7%), 658 of C. tropicalis (14.2%), 503 of C. glabrata (10.9%), 495 of C. parapsilosis (10.7%), 292 of C. rugosa (6.3%), 195 of C. guilliermondii (4.2%) and 89 of other Candida species (2.0%). Only 2.0% of the strains tested were classified as dose-dependent susceptible (DDS), and 5.8% of them were resistant to FCZ. The resistance or DDS to fluconazole was verified mainly among C. glabrata (7.8%), C. krusei (67.9%) and C. rugosa (65.1%). Voriconazole exhibited better activity in vitro than fluconazole, even in isolates fluconazole resistant. The resistance of fluconazole and voriconazole did not increase in the isolates of Candida spp. during the evaluated period.

Changes in cell wall synthesis and ultrastructure during paradoxical growth effect of caspofungin on four different Candida species

Paradoxical growth (PG) has been described for echinocandins and is characterized by cell growth at drug concentrations above the MIC. In this study, two isolates each of Candida albicans, C. tropicalis, C. orthopsilosis, and C. parapsilosis, all of which displaying PG in response to caspofungin, were subjected to MIC, minimal fungicidal concentration (MFC), and time-kill curve assays to evaluate the levels of PG. Cell wall components and ultrastructural modifications of the PG cells were also investigated. The results showed that when cell growth and survival were evaluated by MFC or time-kill curve assays, high concentrations of caspofungin did not show fungicidal activity against PG cells. Furthermore, for C. parapsilosis and C. orthopsilosis, time-kill curves were more discriminatory than MFCs in detecting the PG effect. The four different Candida species studied demonstrated similar alterations in cell wall components and ultrastructure associated with PG. In PG cells, β-1,3-glucan content decreased from 2.7- to 7.8-fold, whereas chitin content increased from 4.0- to 6.6-fold. An electron microscopy study of the PG cells revealed morphological alterations, clumping of cells, enlarged cells, the absence of filamentation, abnormal septa, and accumulation of chitin in the cell wall. Also, PG cells basically exhibited a single dark high-density layer in the cell wall, indicating the loss of the β-1,3-glucan layer. Our results present novel details about the ultrastructural alterations that occur in C. albicans, C. parapsilosis, C. orthopsilosis, and C. tropicalis during PG and show that chitin is the major component of the cell walls of PG cells. Stimulation of chitin synthesis may represent a rescue mechanism against caspofungin activity.

Surveillance programs for detection and characterization of emergent pathogens and antimicrobial resistance: results from the Division of Infectious Diseases, UNIFESP

Several epidemiological changes have occurred in the pattern of nosocomial and community acquired infectious diseases during the past 25 years. Social and demographic changes possibly related to this phenomenon include a rapid population growth, the increase in urban migration and movement across international borders by tourists and immigrants, alterations in the habitats of animals and arthropods that transmit disease, as well as the raise of patients with impaired host defense abilities. Continuous surveillance programs of emergent pathogens and antimicrobial resistance are warranted for detecting in real time new pathogens, as well as to characterize molecular mechanisms of resistance. In order to become more effective, surveillance programs of emergent pathogens should be organized as a multicenter laboratory network connected to the main public and private infection control centers. Microbiological data should be integrated to guide therapy, adapting therapy to local ecology and resistance patterns. This paper presents an overview of data generated by the Division of Infectious Diseases, Federal University of São Paulo, along with its participation in different surveillance programs of nosocomial and community acquired infectious diseases.

Candida Guilliermondii Fungemia in a Critically III Trauma Patient

Objective:

To report a case of fungemia caused by Candida guilliermondii in a non-neutropenic 17-year-old critically ill trauma patient.

Case Summary:

Few case reports and small surveys have reported invasive infection caused by C. guilliermondii, most of which has occurred in immunocompromised populations. We present the case of a 17-year-old trauma patient who developed fungemia with C. guilliermondii during his intensive care unit stay. While he had multiple risk factors for the development of candidemia, this was an atypical finding, considering that this patient was not neutropenic. Due to the variable resistance patterns with this species of Candida, mean inhibitory concentration testing was requested, which demonstrated susceptibility to fluconazole. The patient was thus treated with fluconazole and his fungemia resolved without relapse.

Discussion:

C. guilliermondii accounts for 1–5% of cases of non- albicans Candida. While C. guilliermondii typically does not cause invasive infection, it has been associated with severe, life-threatening candidiasis in immunocompromised patients. Due to its low incidence, guidelines for the management of C. guilliermondii infections have not been well established and specific risk factors have not been identified. While risk factors specific to C. guilliermondii may mimic established risk factors for candidal fungemia in general, an important aspect to consider in the treatment of this fungus is its unique resistance profile compared with other non- albicans species.

Conclusions:

This case illustrates the development of an uncommon fungal pathogen in a non-immunocompromised host, compared with previously published cases series. Susceptibility testing is recommended to prevent therapeutic failures due to varying resistance patterns with C. guilliermondii.

Variation in susceptibility of bloodstream isolates of Candida glabrata to fluconazole according to patient age and geographic location in the United States in 2001 to 2007

We examined the susceptibilities to fluconazole of 642 bloodstream infection (BSI) isolates of Candida glabrata and grouped the isolates by patient age and geographic location within the United States. Susceptibility of C. glabrata to fluconazole was lowest in the northeast region (46%) and was highest in the west (76%). The frequencies of isolation and of fluconazole resistance among C. glabrata BSI isolates were higher in the present study (years 2001 to 2007) than in a previous study conducted from 1992 to 2001. Whereas the frequency of C. glabrata increased with patient age, the rate of fluconazole resistance declined. The oldest age group (> or = 80 years) had the highest proportion of BSI isolates that were C. glabrata (32%) and the lowest rate of fluconazole resistance (5%).

Bloodstream infections due to Trichosporon spp.: species distribution, Trichosporon asahii genotypes determined on the basis of ribosomal DNA intergenic spacer 1 sequencing, and antifungal susceptibility testing

The reevaluation of the genus Trichosporon has led to the replacement of the old taxon Trichosporon beigelii by six new species. Sequencing of the ribosomal DNA (rDNA) intergenic spacer 1 (IGS1) is currently mandatory for accurate Trichosporon identification, but it is not usually performed in routine laboratories. Here we describe Trichosporon species distribution and prevalence of Trichosporon asahii genotypes based on rDNA IGS1 sequencing as well as antifungal susceptibility profiles of 22 isolates recovered from blood cultures. The clinical isolates were identified as follows: 15 T. asahii isolates, five Trichosporon asteroides isolates, one Trichosporon coremiiforme isolate, and one Trichosporon dermatis isolate. We found a great diversity of different species causing trichosporonemia, including a high frequency of isolation of T. asteroides from blood cultures that is lower than that of T. asahii only. Regarding T. asahii genotyping, we found that the majority of our isolates belonged to genotype 1 (86.7%). We report the first T. asahii isolate belonging to genotype 4 in South America. Almost 50% of all T. asahii isolates exhibited amphotericin B MICs of >or=2 microg/ml. Caspofungin MICs obtained for all the Trichosporon sp. isolates tested were consistently high (MICs >or= 2 microg/ml). Most isolates (87%) had high MICs for 5-flucytosine, but all of them were susceptible to triazoles, markedly to voriconazole (all MICs <or= 0.06 microg/ml).

Relationship between susceptibility of Candida spp. isolates to amphotericin B and death or survival of patients with candidemia episodes

In this study, the susceptibility to amphotericin B of Candida spp. isolates obtained from patients with candidemia was related to their respective clinical outcomes. The susceptibility tests were carried out in three culture media: RPMI 1640, Antibiotic medium 3 and Yeast Nitrogen Base dextrose. We have found that minimal inhibitory concentrations and minimal fungicidal concentrations obtained using AM3 and YNBd media were significantly higher for Candida spp. from patients who died than for those from patients who survived the candidemia (P < 0.05). The assays with RPMI 1640 medium did not show these differences.

Candida glabrata fungaemia in intensive care units

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

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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