The changing face of candidemia: emergence of non-Candida albicans species and antifungal resistance

Invasive Fungal Breakthrough Infections under Targeted Echinocandin Prophylaxis in High-Risk Liver Transplant Recipients

Invasive fungal infections (IFIs) are frequent and outcome-relevant complications in the early postoperative period after orthotopic liver transplantation (OLT). Recent guidelines recommend targeted antimycotic prophylaxis (TAP) for high-risk liver transplant recipients (HR-LTRs). However, the choice of antimycotic agent is still a subject of discussion. Echinocandins are increasingly being used due to their advantageous safety profile and the increasing number of non-albicans Candida infections. However, the evidence justifying their use remains rather sparse. Recently published data on breakthrough IFI (b-IFI) raise concerns about echinocandin efficacy, especially in the case of intra-abdominal candidiasis (IAC), which is the most common infection site after OLT. In this retrospective study, we analyzed 100 adult HR-LTRs undergoing first-time OLT and receiving echinocandin prophylaxis between 2017 and 2020 in a tertiary university hospital. We found a breakthrough incidence of 16%, having a significant impact on postoperative complications, graft survival, and mortality. The reasons for this may be multifactorial. Among the pathogen-related factors, we identified the breakthrough of Candida parapsilosis in 11% of patients and one case of persistent IFI due to the development of a secondary echinocandin resistance of an IAC caused by Candida glabrata. Consequently, the efficacy of echinocandin prophylaxis in liver transplantation should be questioned. Further studies are necessary to clarify the matter of breakthrough infections under echinocandin prophylaxis.

Incidence of Invasive Fungal Infections in Liver Transplant Recipients under Targeted Echinocandin Prophylaxis

Invasive fungal infections (IFIs) are one of the most important infectious complications after liver transplantation, determining morbidity and mortality. Antimycotic prophylaxis may impede IFI, but a consensus on indication, agent, or duration is still missing. Therefore, this study aimed to investigate the incidence of IFIs under targeted echinocandin antimycotic prophylaxis in adult high-risk liver transplant recipients. We retrospectively reviewed all patients undergoing a deceased donor liver transplantation at the Medical University of Innsbruck in the period from 2017 to 2020. Of 299 patients, 224 met the inclusion criteria. We defined patients as being at high risk for IFI if they had two or more prespecified risk factors and these patients received prophylaxis. In total, 85% (190/224) of the patients were correctly classified according to the developed algorithm, being able to predict an IFI with a sensitivity of 89%. Although 83% (90/109) so defined high-risk recipients received echinocandin prophylaxis, 21% (23/109) still developed an IFI. The multivariate analysis identified the age of the recipient (hazard ratio-HR = 0.97, p = 0.027), split liver transplantation (HR = 5.18, p = 0.014), massive intraoperative blood transfusion (HR = 24.08, p = 0.004), donor-derived infection (HR = 9.70, p < 0.001), and relaparotomy (HR = 4.62, p = 0.003) as variables with increased hazard ratios for an IFI within 90 days. The fungal colonization at baseline, high-urgency transplantation, posttransplant dialysis, bile leak, and early transplantation showed significance only in a univariate model. Notably, 57% (12/21) of the invasive Candida infections were caused by a non-albicans species, entailing a markedly reduced one-year survival. The attributable 90-day mortality rate of an IFI after a liver transplant was 53% (9/17). None of the patients with invasive aspergillosis survived. Despite targeted echinocandin prophylaxis, there is still a notable risk for IFI. Consequently, the prophylactic use of echinocandins must be critically questioned regarding the high rate of breakthrough infections, the increased occurrence of fluconazole-resistant pathogens, and the higher mortality rate in non-albicans Candida species. Adherence to the internal prophylaxis algorithms is of immense importance, bearing in mind the high IFI rates in case algorithms are not followed.

Fungal infection and neurodevelopmental outcomes at 18-30 months in preterm infants

Background

Invasive fungal infection (IFI) is associated with significant mortality and morbidity among preterm infants but there has been no population-based study of long-term neurodevelopmental outcomes. The objective of this study was to examine population-based incidence trends as well as mortality, short term in-hospital morbidity and long-term neurodevelopmental outcomes among preterm infants with IFI, non-fungal infections (NFI) and no infections in Canada.

Methods

We conducted a retrospective cohort study of 8,408 infants born at <29 weeks gestational age (GA), admitted to Canadian Neonatal Network neonatal intensive care units (NICU) from April 2009 to December 2017, and followed up at 18-30 months corrected age (CA) in Canadian Neonatal Follow-Up Network clinics. We compared mortality, long term neurodevelopmental outcomes and short term in-hospital morbidity among 3 groups of infants (IFI, NFI, and no infections).

Results

The incidence of IFI was 1.3%, non-IFI 26.9% and no infections 71.7%. IFI incidence varied between 0.93% and 1.94% across the study period with no significant trend over time. Infants of higher gestational age were significantly (p < 0.01) less likely to have IFI. Among infants with IFI, NFI and no infections, the incidence of the significant neurodevelopmental impairment (sNDI) was 44.26%, 21.63% and 14.84% respectively, while mortality was 50%, 25.35% and 22.25% respectively. Even after risk adjustment for confounders (GA, Score for Neonatal Acute Physiology Version II, ruptured membranes >24 h, maternal antibiotic treatment, antenatal steroid use, cesarean section), infants with IFI had significantly higher odds of sNDI than NFI (aOR: 2.19; 95% CI: 1.23, 3.91) or no infections (aOR: 2.97; 95% CI: 1.55, 5.71), and higher odds of mortality than NFI (aOR: 1.55; 95% CI: 1.07, 2.26) or no infections (aOR: 1.45; 95% CI: 0.97, 2.17).

Conclusions

Preterm infants with invasive fungal infections have significantly higher incidence of mortality and adverse neurodevelopmental outcomes than those with non-invasive fungal infections and no infections.

Little Utility of Fungal Blood Cultures in Surgical and Burn Intensive Care Units

Critically ill patients are at risk for fungal infections, but there is a paucity of data regarding the clinical utility of dedicated fungal blood cultures to detect such infections. A retrospective review was conducted of patients admitted to the surgical and burn intensive care units at Parkland Memorial Hospital between 1 January 2013 and 31 December 2017 for whom blood cultures (aerobic, anaerobic, and/or fungal cultures) were sent. A total of 1,094 aerobic and anaerobic blood culture sets and 523 fungal blood cultures were sent. Of the aerobic and anaerobic culture sets, 42/1,094 (3.8%) were positive for fungal growth. All fungal species cultured were Candida. Of the fungal blood cultures, 4/523 (0.76%) were positive for growth. Fungal species isolated included Candida albicans, Aspergillus fumigatus, and Histoplasma capsulatum. All 4 patients with positive fungal blood cultures were on empirical antifungal therapy prior to results, and the antifungal regimen was changed for 1 patient based on culture data. The average duration to final fungal culture result was 46 days, while the time to preliminary results varied dramatically. Two of the four patients died prior to fungal culture results, thereby rendering the culture data inconsequential in patient care decisions. This study demonstrates that regular aerobic and anaerobic blood cultures sets are sufficient in detecting the most common causes of fungemia and that results from fungal cultures rarely impact treatment management decisions in patients in surgical and burn intensive care units. There is little clinical utility to routine fungal cultures in this patient population. IMPORTANCE This study demonstrates that regular aerobic and anaerobic blood culture sets are sufficient in detecting the most common causes of fungemia, and thus, sending fungal blood cultures for patients in surgical and burn intensive care units is not a good use of resources.

Clinical utility of antifungal susceptibility testing

Invasive fungal diseases cause significant morbidity and mortality, in particular affecting immunocompromised patients. Resistant organisms are of increasing importance, yet there are many notable differences in the ability to both perform and interpret antifungal susceptibility testing compared with bacteria. In this review, we will highlight the strengths and limitations of resistance data of pathogenic yeasts and moulds that may be used to guide treatment and predict clinical outcomes.

Increasing Incidence and Shifting Epidemiology of Candidemia in Greece: Results from the First Nationwide 10-Year Survey

Globally, candidemia displays geographical variety in terms of epidemiology and incidence. In that respect, a nationwide Greek study was conducted, reporting the epidemiology of Candida bloodstream infections and susceptibility of isolates to antifungal agents providing evidence for empirical treatment. All microbiologically confirmed candidemia cases in patients hospitalized in 28 Greek centres during the period 2009–2018 were recorded. The study evaluated the incidence of infection/100,000 inhabitants, species distribution, and antifungal susceptibilities of isolated strains. Overall, 6057 candidemic episodes occurred during the study period, with 3% of them being mixed candidemias. The average annual incidence was 5.56/100,000 inhabitants, with significant increase over the years (p = 0.0002). C. parapsilosis species complex (SC) was the predominant causative agent (41%), followed by C. albicans (37%), C. glabrata SC (10%), C. tropicalis (7%), C. krusei (1%), and other rare Candida spp. (4%). C. albicans rates decreased from 2009 to 2018 (48% to 31%) in parallel with a doubling incidence of C. parapsilosis SC rates (28% to 49%, p < 0.0001). Resistance to amphotericin B and flucytosine was not observed. Resistance to fluconazole was detected in 20% of C. parapsilosis SC isolates, with a 4% of them being pan-azole-resistant. A considerable rising rate of resistance to this agent was observed over the study period (p < 0.0001). Echinocandin resistance was found in 3% of C. glabrata SC isolates, with 70% of them being pan-echinocandin-resistant. Resistance rate to this agent was stable over the study period. This is the first multicentre nationwide study demonstrating an increasing incidence of candidemia in Greece with a species shift toward C. parapsilosis SC. Although the overall antifungal resistance rates remain relatively low, fluconazole-resistant C. parapsilosis SC raises concern.

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.

Clinical characteristics and outcome of candidemia: Experience from a tertiary referral center in Saudi Arabia

Background:

Candida bloodstream infections cause significant excess morbidity and mortality in the health-care setting. There is limited evidence regarding Candida species causing invasive infections in Saudi Arabia.

Objective:

To identify Candida species causing bloodstream infection and determine the clinical outcome and factors associated with mortality in a tertiary center in Saudi Arabia.

Materials and Methods:

This retrospective study included all cases of positive blood culture for Candida in patients admitted to King Abdulaziz Medical City, a tertiary care center in Riyadh, Saudi Arabia, between January 1, 2013 and June 30, 2019.

Results:

A total of 532 patients with candidemia were identified (male: 55.4%; mean age: 54 ± 26.2 years). The most common Candida species isolated was Candida albicans (26.7%), followed by Candida glabrata (22.7%), Candida parapsilosis (22.2%), and Candida tropicalis (18.4%). Non-albicans candidemia was more common in patients with diabetes (76.7%; P = 0.0560), neutropenia (89.8%; P = 0.0062), recent exposure to fluconazole (85.7%; P = 0.0394), and active chemotherapy (83.1%; P = 0.0128). In non-albicans, susceptibility to fluconazole varied from 95.9% with C. tropicalis to 41.5% with C. parapsilosis; nonetheless, all species were highly susceptible to echinocandins. The overall 30- and 90-day mortality rates were 39.9% and 56.4%, respectively. The mortality rate was nonsignificantly higher with non-albicans species at 30 days (41.2% vs. 35.9%; P = 0.2634) and 90 days (58.2% vs. 51.4%; P = 0.1620).

Conclusion:

This study found a changing pattern in the Candida species causing bloodstream infections and an epidemiological shift toward more non-albicans Candida species in Saudi Arabia.

Temporal Trends in the Microbiological Characteristics of Sepsis in the United States: A Population Based Study

BACKGROUND

Epidemiologic studies are needed for monitoring population-level trends in sepsis. This study examines sepsis-causing microorganisms from 2006 to 2014 in the United States using data from the Nationwide Inpatient Sample database.

METHODS

7 860 686 adults hospitalized with sepsis were identified using a validated ICD-9 coding approach. Associated microorganisms were identified by ICD-9 code and classified by major groups (Gram-positive, Gram-negative, fungi, anaerobes) and specific species for analysis of their incidence and mortality.

RESULTS

The rate of sepsis incidence has increased for all four major categories of pathogens, while the mortality rate decreased. In 2014, Gram-negative pathogens had a higher incidence than Gram-positives. Anaerobes increased the fastest with an average annual increase of 20.17% (p < 0.001). Fungi had the highest mortality (19.28%) and the slowest annual decrease of mortality (-2.31%, p = 0.006) in 2013, while anaerobic sepsis had the highest hazard of mortality (adjusted HR 1.60, 95% CI 1.53-1.66).

CONCLUSIONS

Gram-negative pathogens have replaced Gram-positives as the leading cause of sepsis in the United States in 2014 during the study period (2006-2014). The incidence of anaerobic sepsis has an annual increase of 20%, while the mortality of fungal sepsis has not decreased at the same rate as other microorganisms. These findings should inform the diagnosis and management of septic patients, as well as the implementation of public health programs.

Post-transcriptional and translational control of the morphology and virulence in human fungal pathogens

Host-pathogen interactions at the molecular level are the key to fungal pathogenesis. Fungal pathogens utilize several mechanisms such as adhesion, invasion, phenotype switching and metabolic adaptations, to survive in the host environment and respond. Post-transcriptional and translational regulations have emerged as key regulatory mechanisms ensuring the virulence and survival of fungal pathogens. Through these regulations, fungal pathogens effectively alter their protein pool, respond to various stress, and undergo morphogenesis, leading to efficient and comprehensive changes in fungal physiology. The regulation of virulence through post-transcriptional and translational regulatory mechanisms is mediated through mRNA elements (cis factors) or effector molecules (trans factors). The untranslated regions upstream and downstream of the mRNA, as well as various RNA-binding proteins involved in translation initiation or circularization of the mRNA, play pivotal roles in the regulation of morphology and virulence by influencing protein synthesis, protein isoforms, and mRNA stability. Therefore, post-transcriptional and translational mechanisms regulating the morphology, virulence and drug-resistance processes in fungal pathogens can be the target for new therapeutics. With improved "omics" technologies, these regulatory mechanisms are increasingly coming to the forefront of basic biology and drug discovery. This review aims to discuss various modes of post-transcriptional and translation regulations, and how these mechanisms exert influence in the virulence and morphogenesis of fungal pathogens.

Synergistic Anticandidal Effects of Six Essential Oils in Combination with Fluconazole or Amphotericin B against Four Clinically Isolated Candida Strains

The development of opportunistic pathogenic Candida strains insensitive to several classes of antifungals has emerged as a major health care problem during the last years. Combinational therapy of natural products (e.g., essential oils, EOs) with conventional antifungals has been suggested as a promising alternative to overcome this medical problem. The present study investigates the potential antifungal activity of EOs extracted from some selected medicinal plants, alone and in combination with two common conventional antifungals (fluconazole and amphotericin B) against four clinical Candida isolates. MIC assays indicated that EOs induced strong anticandidal activities with MIC values ranging from 0.162 to 4.950 mg/mL. The combination of amphotericin B with Thymus leptobotrys, Origanum compactum and Artemisia herba alba EOs provided a synergistic effect against C. krusei only, with MIC gain of four-fold, and additive effect against remaining strains (MIC gain = two-fold). Interesting synergistic interactions were observed by combining all studied EOs with fluconazole, with reduction rates of their MICs ranging from 16 to 512-fold. This synergistic effect was very pronounced with the combination of T. leptobotrys EO and fluconazole. These findings indicate that studied EOs can be used as anti-candidals in combination with antifungals, particularly fluconazole, to counteract the emergence of resistant Candida spp.

Genetic Manipulation as a Tool to Unravel Candida parapsilosis Species Complex Virulence and Drug Resistance: State of the Art

An increase in the rate of isolation of Candida parapsilosis in the past decade, as well as increased identification of azole-resistant strains are concerning, and require better understanding of virulence-like factors and drug-resistant traits of these species. In this regard, the present review “draws a line” on the information acquired, thus far, on virulence determinants and molecular mechanisms of antifungal resistance in these opportunistic pathogens, mainly derived from genetic manipulation studies. This will provide better focus on where we stand in our understanding of the C. parapsilosis species complex–host interaction, and how far we are from defining potential novel targets or therapeutic strategies—key factors to pave the way for a more tailored management of fungal infections caused by these fungal pathogens.

The impact of the Fungus-Host-Microbiota interplay upon Candida albicans infections: current knowledge and new perspectives

Candida albicans is a major fungal pathogen of humans. It exists as a commensal in the oral cavity, gut or genital tract of most individuals, constrained by the local microbiota, epithelial barriers and immune defences. Their perturbation can lead to fungal outgrowth and the development of mucosal infections such as oropharyngeal or vulvovaginal candidiasis, and patients with compromised immunity are susceptible to life-threatening systemic infections. The importance of the interplay between fungus, host and microbiota in driving the transition from C. albicans commensalism to pathogenicity is widely appreciated. However, the complexity of these interactions, and the significant impact of fungal, host and microbiota variability upon disease severity and outcome, are less well understood. Therefore, we summarise the features of the fungus that promote infection, and how genetic variation between clinical isolates influences pathogenicity. We discuss antifungal immunity, how this differs between mucosae, and how individual variation influences a person's susceptibility to infection. Also, we describe factors that influence the composition of gut, oral and vaginal microbiotas, and how these affect fungal colonisation and antifungal immunity. We argue that a detailed understanding of these variables, which underlie fungal-host-microbiota interactions, will present opportunities for directed antifungal therapies that benefit vulnerable patients.

Candida Empyema Thoracis at Two Academic Medical Centers: New Insights Into Treatment and Outcomes

Background

Candida empyema thoracis (pleural empyema) is an uncommon manifestation of invasive candidiasis, for which optimal treatment is unknown.

Methods

This is a retrospective study of patients with Candida empyema at 2 academic medical centers from September 2006 through December 2015.

Results

We identified 81 patients with Candida empyema (median age, 62 years; 68% men). Sixty-five percent of patients underwent surgery or an invasive intervention of the thorax or abdomen within the preceding 90 days. Candida empyema originated from intrathoracic (51%) or intra-abdominal sources (20%), spontaneous esophageal rupture (12%), pleural space manipulation (9%), and pneumonia (6%). Eighty-four percent and 41% of patients were intensive care unit residents and in septic shock, respectively, within 3 days of diagnosis. Causative species were Candida albicans (65%), Candida glabrata (26%), Candida parapsilosis (11%), Candida tropicalis (4%), Candida krusei (2%), and Candida dubliniensis (1%). Bacteria were recovered from empyemas in 51% of patients. Concurrent candidemia was diagnosed in only 2% of patients. Management included pleural drainage and antifungal treatment in 98% and 85% of patients, respectively. Mortality at 100 days was 27%, and it was highest for cases stemming from esophageal rupture (67%). Spontaneous esophageal rupture and echinocandin rather than fluconazole treatment were independent risk factors for death at 100 days (P = .003 and .04, respectively); receipt of antifungal therapy was an independent predictor of survival (P = .046).

Conclusions

Candida empyema mortality rates were lower than reported previously. Optimal management included pleural drainage and fluconazole treatment. Superiority of fluconazole over echinocandins against Candida empyema needs to be confirmed in future studies.

Isolation and identification of Candida tropicalis in sows with fatal infection: a case report

Background

Candida is the common conditionally pathogenic fungus that infected human and animal clinically. C. tropicalis had been isolated from the skin and hair of healthy pigs, but with no report of fatal infection in gastrointestinal diseases.

Case presentation

In a pig farm in Henan Province of China, about 20 % of pregnant and postpartum sows suffered from severe gastrointestinal diseases, with a mortality rate higher than 60 % in the diseased animals. The sows had gastrointestinal symptoms such as blood in stool and vomiting. Necropsy revealed obvious gastric ulcers, gastrointestinal perforation, and intestinal hemorrhage in the gastrointestinal tract, but no lesions in other organs. The microbial species in gastric samples collected from gastric ulcer of the diseased sows then was initially identified as Candida by using routine systems of microscopic examination, culture characteristics on the medium Sabouraud dextrose agar medium. The fungus was further identified as C. tropicalis by species-specific PCR and sequencing. This study revealed an infection of C. tropicalis in sows through gastrointestinal mucosa could cause fatal digestive system disease and septicemia.

Conclusions

For the first time, a strain of C. tropicalis was isolated and identified from the gastric tissue of sows with severe gastrointestinal diseases. PCR and sequencing of ITS-rDNA combined with morphology and histopathological assay were reliable for the identification of Candida clinically.

Oceanapiside, a Marine Natural Product, Targets the Sphingolipid Pathway of Fluconazole-Resistant Candida glabrata

Oceanapiside (OPS), a marine natural product with a novel bifunctional sphingolipid structure, is fungicidal against fluconazole-resistant Candida glabrata at 10 μg/mL (15.4 μM). The fungicidal effect was observed at 3 to 4 h after exposure to cells. Cytological and morphological studies revealed that OPS affects the budding patterns of treated yeast cells with a significant increase in the number of cells with single small buds. In addition, this budding morphology was found to be sensitive in the presence of OPS. Moreover, the number of cells with single medium-sized buds and cells with single large buds were decreased significantly, indicating that fewer cells were transformed to these budding patterns, suggestive of inhibition of polarized growth. OPS was also observed to disrupt the organized actin assembly in C. glabrata, which correlates with inhibition of budding and polarized growth. It was also demonstrated that phytosphingosine (PHS) reversed the antifungal activity of oceanapiside. We quantified the amount of long chain-bases (LCBs) and phytoceramide from the crude extracts of treated cells using LC-ESI-MS. PHS concentration was elevated in extracts of cells treated with OPS when compared with cells treated with miconazole and amphotericin B. Elevated levels of PHS in OPS-treated cells confirms that OPS affects the pathway at a step downstream of PHS synthesis. These results also demonstrated that OPS has a mechanism of action different to those of miconazole and amphotericin B and interdicts fungal sphingolipid metabolism by specifically inhibiting the step converting PHS to phytoceramide.

Change in species distribution and antifungal susceptibility of candidemias in an intensive care unit of a university hospital (10-year experience)

Candidemia is a nosocomial infection mostly found in critically ill patients. Our objectives were to evaluate the change in distribution and resistance profile of Candida spp. isolated from candidemic patients in our intensive care unit over two 5-year periods spanning 15 years and to evaluate the risk factors. Records from the microbiology laboratory were obtained, from January 2004 to December 2008 and from January 2013 to December 2017, retrospectively. Antifungal susceptibility was performed by E-test and evaluated according to EUCAST breakpoints. A total of 210 candidemia cases occurred; 238 Candida spp. were isolated in 197 patients (58.8% male; mean age, 59.2 ± 19.6 years). The most predominant risk factor was central venous catheter use. Species distribution rates were 32%, 28%, 17%, and 11% for C. albicans (n = 76), C. parapsilosis (n = 67), C. glabrata (n = 40), and C. tropicalis (n = 27), respectively. Resistance rate to anidulafungin was high in C. parapsilosis over both periods and increased to 73% in the second period. Fluconazole showed a remarkable decrease for susceptibility in C. parapsilosis (94 to 49%). The prevalence of MDR C. parapsilosis (6%/33%) and C. glabrata (0%/44%) increased in the second period. We observed a predominance of non-albicans Candida spp., with C. parapsilosis being the most frequent and C. glabrata infections presenting with the highest mortality. High level of echinocandin resistance in C. parapsilosis and increasing prevalences of MDR C. parapsilosis and C. glabrata seem emerging challenges in our institution.

Clinical characteristics, management and outcome of patients with invasive candidiasis hospitalized in Internal Medicine Units: findings from a registry by the Italian Scientific Society FADOI

PURPOSE

Invasive candidiasis (IC) is a challenging clinical condition, burdened by relevant mortality and morbidity. There is limited knowledge on the occurrence and management of IC in Internal Medicine Units (IMUs). Aim of this study was to provide real-world data on this topic.

METHODS

Consecutive objectively diagnosed cases of IC were collected in this prospective registry, which involved 18 IMUs in Italy. Patients were followed-up to 90 days from the diagnosis of candidemia.

RESULTS

A total of 111 patients were observed (median age 78, IQR 67-83) for an overall incidence of infection of 1.89 cases/1000 hospital admissions. Candida albicans was the most frequent isolated species (62%), followed by Candida parapsilosis (17%) and Candida glabrata (13%). Echinocandins and fluconazole were used as initial therapy in 56.8 and 43.2% of patients, respectively. Antifungal therapy was started within 24 h in 18.9% of patients, in 40.6% in the period 1-3 days, and in 40.5% of patients more than 3 days after blood cultures. Death rate was 19.8% at 30 days and 40.5% at 90 days. At multivariable analysis concomitant bacteremia (i.e. polymicrobial sepsis), and fluconazole as the initial therapy were associated with an increased risk of death at 90 days.

CONCLUSIONS

The incidence of IC is not negligible, and our registry confirmed that these patients have a relevant mortality rate at 90 days. Concomitant bacteremia, featuring polymicrobial sepsis, and starting antifungal treatment with fluconazole instead of echinocandins independently increase the risk of death. Efforts are needed to improve the awareness and management of IC in IMUs.

The prevalence and clinical significance of microcolonies when tested according to contemporary interpretive breakpoints for fluconazole against Candida species using E-test

Changes in the interpretive-breakpoints for antifungals against various Candida species have raised the need to examine the significance of the phenomenon of the growth of microcolonies in agar diffusion inhibition zones, which has generally been considered negligible. The objective was to determine the incidence of cases in which microcolonies demonstrate fluconazole resistance according to current interpretive-breakpoints and whether their growth is associated with therapeutic failure. The fluconazole minimum inhibitory concentrations (MICs) of 100 blood culture isolates of Candida were performed by E-test on Roswell Park Memorial Institute (RPMI) agar and examined for the appearance of microcolonies. Fluconazole MICs of microcolonies were then determined over three generations. The significance of the phenomenon of microcolonies was determined according to clinical data retrieved from electronic files. Microcolonies were a common phenomenon among Candida isolates following incubation on RPMI agar, with a higher frequency among C. albicans isolates as compared to non-albicans Candida across generations (57-93% vs 31-93%, respectively) and a similar fluconazole susceptibility rate over three generations. The rate of microcolonies was similar in both patients with successful and unsuccessful outcome (41% vs 42%, respectively). Microcolonies are a common phenomenon. No increase in MIC was demonstrated throughout three generations of microcolony inoculation on RPMI, and no difference in clinical outcome was observed.

Dynamic study of oral Candida infection and immune status in HIV infected patients during HAART

OBJECTIVE

To dynamically monitor oral Candida infection, CD4⁺ T lymphocyte counts, CD8⁺ T lymphocyte counts and CD4/CD8 ratios in HIV/AIDS patients during their first year of HAART and to preliminarily explore the relationships between them.

DESIGN

Forty-six patients with HIV/AIDS receiving HAART at the Infection Department of Chongqing Red Cross Hospital were followed for one year. At baseline and 3, 6, and 12 months after HAART initiation, oral rinses were collected and cultured to identify Candida species. Further, blood samples were collected to detect CD4⁺ T lymphocyte counts, CD8⁺ T lymphocyte counts and CD4/CD8 ratios.

RESULTS

The prevalence of OC decreased after HAART initiation (P ＜ 0.05), and Candida albicans was the dominant species isolated from the oral cavity (66/93). At 3, 6 and 12 months after HAART initiation, CD4⁺ T lymphocyte counts were 327.91 ± 138.82, 329.65 ± 142.66 and 319.98 ± 97.90 cells/mm³, respectively, which were significantly higher than the level at baseline (263.39 ± 126.01 cells/mm³) (P = 0.016, P = 0.014, and P = 0.035, respectively). During the first year of HAART, CD4/CD8 ratios increased gradually, and CD8⁺ T lymphocyte counts decreased continually. OC was associated with low CD4⁺ T lymphocyte counts and a low CD4/CD8 ratio. CD4⁺ T lymphocyte counts <200 cells/mm³ and Candida load ≥300 CFU/mL were risk factors for OC (P ＜ 0.05), and oral Candida load was negatively correlated with CD4⁺ T lymphocyte counts and the CD4/CD8 ratio.

CONCLUSION

OC might be a useful marker for the evaluation of immune status in patients with HIV/AIDS.

Mixed fungaemia: an 18-year report from a tertiary-care university hospital and a systematic review

BACKGROUND

While fungaemia caused by two or more different species of yeasts (mixed fungaemia, MF) is infrequent, it might be underestimated.

AIMS

This study aimed to determine the incidence of MF, clinical characteristics of the patients, and antifungal susceptibility profiles of the isolates with a systematic review of the literature.

SOURCES

Data sources were PubMed and Scopus.

STUDY ELIGIBILITY CRITERIA

Studies reporting ten or more mixed fungaemia episodes.

CONTENT

Study included MF episodes in adults between January 2000 and August 2018 in Hacettepe University Hospitals, Turkey. The isolation, identification and antifungal susceptibility testing (AFST) of the isolates were by standard mycological methods. Patient data were obtained retrospectively. Literature search was performed using relevant keywords according to PRISMA systematic review guidelines. A total of 32 patients with 33 MF episodes were identified. Among all fungaemia episodes, MF incidence was 3.7% (33/883). All patients had one or more underlying disorders among which solid-organ cancer (50.0%, 16/32) was the most common. Overall mortality was 51.5% (17/33). The most preferred antifungal agents for initial treatment were fluconazole (48.5%, 16/33) and echinocandins (39.4%, 13/33). Fluconazole susceptible-dose-dependent (S-DD) or -resistant Candida species were detected in 15 episodes, and an isolate of C. parapsilosis was classified as S-DD by AFST. All Candida isolates were susceptible to echinocandins. Non-candida yeasts with intrinsic resistance/reduced susceptibility to both echinocandins and fluconazole were detected in two episodes. Systematic review of the literature revealed 24 studies that reported more than ten MF episodes. Methodology was variable. Improvement of detection rates was reported when chromogenic agars were used. Most studies underlined detection of isolates with reduced susceptibility.

IMPLICATIONS

Although rare, the MF rate is affected by the detection methods, which have improved in recent years. Fluconazole and echinocandins were used for initial treatment in accordance with the current guideline recommendations; however, isolates non-susceptible to both were detected. Detection of a mixed infection offers an opportunity for optimum treatment.

Candida blood stream infections observed between 2011 and 2016 in a large Italian University Hospital: A time-based retrospective analysis on epidemiology, biofilm production, antifungal agents consumption and drug-susceptibility

Candida bloodstream infection (BSI) represents a growing infective problem frequently associated to biofilm production due to the utilization of intravascular devices. Candida species distribution (n = 612 strains), their biofilm production and hospital antifungal drug consumption were evaluated in different wards of a tertiary care academic hospital in Italy during the years 2011–2016. In the considered time window, an increasing number of Candida BSI (p = 0.005) and of biofilm producing strains were observed (p<0.0001). Although C. albicans was the species more frequently isolated in BSI with a major biofilm production, an increased involvement of non-albicans species was reported, particularly of C. parapsilosis that displayed a high frequency in catheter infections, and lower biofilm production compared to C. albicans. Although trends of biofilm production were substantially stable in time, a decreasing biofilm production by C. parapsilosis in the Intensive Care Unit (ICU) was observed (p = 0.0041). Principal component analysis displayed a change in antifungal drugs consumption driven by two mutually independent temporal trends, i.e. voriconazole use in the general medicine wards initially, and fluconazole use mainly in the ICU; these factors explain 68.9% and 25.7% of total variance respectively. Moreover, a significant trend (p = 0.003) in fluconazole use during the whole time period considered emerged, particularly in the ICU (p = 0.017), but also in the general medicine wards (p = 0.03). These trends paralleled with significant increase MIC90 of fluconazole (p = 0.05), particularly for C. parapsilosis in the ICU (p = 0.04), with a general and significant decreased trend of the MIC90 values of caspofungin (p = 0.04), and with significant increased MIC50 values for amphotericin B (p = 0.01) over the study period. In conclusion, drug utilization in our hospital turned out to be a putative influencing factor on the ecology of the species, on the increase in time of the biofilm producing strains and on the Candida antifungal susceptibility profile, thus influencing clinical management.

Extensive ERG11 mutations associated with fluconazole-resistant Candida albicans isolated from HIV-infected patients

Background and Purpose:

Azoles are preferred antifungal agents given their inexpensiveness, limited toxicity, and potentiality of oral administration. However, the extensive use of prophylactic azole therapy for chronic infections, especially in immunocompromised patients, has led to an increase in azole resistance, thereby rising health care costs. Fluconazole resistance is associated with poor clinical outcomes and the emergence of new infections. The present study aimed to investigate the mutations of ERG11 gene in fluconazole-resistant Candida albicans isolates.

Materials and Methods:

This study was conducted on 80 clinical samples collected from HIV-infected patients with suspected candidiasis in Tagore Medical College Hospital and Government Hospital of Thoracic Medicine, Chennai, India, for a period of 18 months (May 2016-December 2017). The antifungal susceptibility pattern was determined by agar diffusion and broth dilution techniques as per the Clinical and Laboratory Standards Institute guidelines. The ERG11 gene of the known fluconazole-resistant strains of C. albicans was amplified by polymerase chain reaction (PCR). In addition, the samples were subjected to sequencing and mutation analysis.

Results:

A total of 60 Candida species were isolated from HIV patients and were speciated using standard, conventional, and molecular methods. Candida albicans comprised 28.3% (n=17) of the Candida isolates, 59% (n=10) of which were resistant to fluconazole. Sequencing of the amplified product of ERG11C. albicans gene isolates showed that they were highly mutated and included many nonsense mutations which were not reported earlier.

Conclusion:

The molecular characterization of ERG11 gene showed many missense and nonsense mutations. Such mutations, which were unique to the geographical area under investigation, could be concluded to account for the development of resistance to fluconazole.

Incidence, Risk Factors, and Long-term Outcome of Acute Leukemia Patients With Early Candidemia After Allogeneic Stem Cell Transplantation: A Study by the Acute Leukemia and Infectious Diseases Working Parties of European Society for Blood and Marrow Transplantation

Background

This study was performed to assess the incidence of and risk factors for Candida infection in the first 100 days after allogeneic hematopoietic stem cell transplantation (HSCT) and the impact on long-term survival.

Methods

We performed an outcome analysis of 28542 acute leukemia patients who underwent HSCT from 2000 to 2012. There were 347 patients with candidemia by day 100 and 28195 without candidemia or any other type of Candida infection.

Results

The incidence of candidemia by day 100 was 1.2% and occurred at a median of 22 days after HSCT. Higher 100-day nonrelapse mortality (NRM; hazards ratio [HR], 3.0, P < .0001) and lower 100-day overall survival (OS; HR, 2.5, P < .0001) were observed in patients with candidemia. The case fatality rate by day 100 in patients with candidemia was 22% (76/347). Factors associated with candidemia occurrence were female gender, bone marrow or cord blood stem cell source, T-cell depletion, use of total body irradiation, and acute graft vs host disease. Among the patients alive at day 100, the 5-year NRM and OS after a median follow-up of 5.6 years (95% confidence interval, 5.5 - 5.7) for patients with and without candidemia were 22.5% vs 13.5%, P < .0001 and 45.6% vs. 53.4%, P = .0003, respectively. In multivariate analysis, the occurrence of a candidemia episode by day 100 was an independent risk factor for higher NRM (HR, 1.7, P = .001) and lower OS (HR, 1.4, P = .001).

Conclusions

The early occurrence of candidemia after HSCT is still associated with higher NRM and lower short- and-long-term OS.

Exophiala dermatitidis Fungemia Diagnosed Using Time-of-flight Mass Spectrometry during Chemotherapy for Malignant Lymphoma and Successful Treatment with Voriconazole

Infectious diseases, including those caused by fungi, remain important issues in patients receiving malignant lymphoma chemotherapy. We herein report a rare case of Exophiala dermatitidis fungemia during chemotherapy in a 67-year-old woman admitted to our hospital. She had a fever that could not be resolved despite antifungal therapy. Yeast-like fungi were detected in blood culture samples, but biochemical identification was difficult. E. dermatitidis, a black mold, was identified using time-of-flight mass spectrometry. The patient finally improved after her treatment was switched to voriconazole. Fungal infection is difficult to diagnose and treat, but this novel approach can improve patients' outcomes.

A Novel, Drug Resistance-Independent, Fluorescence-Based Approach To Measure Mutation Rates in Microbial Pathogens

Measurements of mutation rates—i.e., how often proliferating cells acquire mutations in their DNA—are essential for understanding cellular processes that maintain genome stability. Many traditional mutation rate measurement assays are based on detecting mutations that cause resistance to a particular drug. Such assays typically work well for laboratory strains but have significant limitations when comparing clinical or environmental isolates that have various intrinsic levels of drug tolerance, which confounds the interpretation of results. Here we report the development and validation of a novel method of measuring mutation rates, which detects mutations that cause loss of fluorescence rather than acquisition of drug resistance. Using this method, we measured the mutation rates of clinical isolates of fungal pathogen Candida glabrata. This assay can be adapted to other organisms and used to compare mutation rates in contexts where unequal drug sensitivity is anticipated.

All evolutionary processes are underpinned by a cellular capacity to mutate DNA. To identify factors affecting mutagenesis, it is necessary to compare mutation rates between different strains and conditions. Drug resistance-based mutation reporters are used extensively to measure mutation rates, but they are suitable only when the compared strains have identical drug tolerance levels—a condition that is not satisfied under many “real-world” circumstances, e.g., when comparing mutation rates among a series of environmental or clinical isolates. Candida glabrata is a fungal pathogen that shows a high degree of genetic diversity and fast emergence of antifungal drug resistance. To enable meaningful comparisons of mutation rates among C. glabrata clinical isolates, we developed a novel fluorescence-activated cell sorting-based approach to measure the mutation rate of a chromosomally integrated GFP gene. We found that in Saccharomyces cerevisiae this approach recapitulated the reported mutation rate of a wild-type strain and the mutator phenotype of a shu1Δ mutant. In C. glabrata, the GFP reporter captured the mutation rate increases caused either by a genotoxic agent or by deletion of DNA mismatch repair gene MSH2, as well as the specific mutational signature associated with msh2Δ. Finally, the reporter was used to measure the mutation rates of C. glabrata clinical isolates carrying different alleles of MSH2. Together, these results show that fluorescence-based mutation reporters can be used to measure mutation rates in microbes under conditions of unequal drug susceptibility to reveal new insights about drivers of mutagenesis.

Prevention and Treatment of Yeast and Endemic Fungal Infections

Invasive fungal infections (IFIs) remain an important complication of solid organ transplantation owing to their significant morbidity and mortality and include infections due to Candida, Cryptococcus, endemic mycosis, and other rare yeasts and molds. IFIs occur in different intervals posttransplantation and depend on a number of extrinsic and intrinsic risk factors, some of which are specific to the type of organs transplanted, surgical techniques, and type of immunosuppressive medications. Donor-derived IFIs and emergence of new multidrug-resistant yeasts have been reported in various healthcare settings. Clinical manifestations of yeast and endemic fungal infections vary in different types of organ transplants. Diagnosis of IFIs in SOT recipients is challenging due to their nonspecific signs and symptoms owing to the impaired inflammatory responses as a result of immunosuppression and the lack of highly sensitive and specific diagnostic modalities. Early diagnosis is key to successful therapy, and physicians should have a high index of suspicion based on risk factors and epidemiology of these pathogens. Antifungal treatment strategies for yeast infections have been outlined in various society guidelines. Management of complications that arise before or during antifungal therapy is critical for optimizing clinical response.

Catheter-related candidemia and identification of causative Candida species in patients with cardiovascular disorder

Background and Purpose

Catheter-related blood circulation infection is the most dangerous and serious side-effects of vascular catheters, which leads to the enhancement of the costs, mortality, and hospital stay duration, especially in the Intensive Care Unit. Regarding this, the aim of the current study was to identify the prevalence of catheter-induced candidemia in the Tehran Heart Center, a heart hospital in Tehran, Iran.

Materials and Methods

This study was conducted on patients admitted to Tehran Heart Center for a minimum of 7 days during 18 months. To detect the fungal elements, blood culture and catheter culture were performed in the patients receiving central or peripheral venous catheter. Then, the polymerase chain reaction (PCR) was applied to determine the possible diagnosis.

Results

The investigation of 223 samples led to the identification of a total of 15 (6.7%) yeast isolates obtained from 9 (60%), 4 (26.6 %), and 2 (13.4%) catheter, blood, and skin (of the catheter insertion areas) cultures, respectively. Out of nine Candida isolates obtained from the catheter samples, 1 (11.1%), 1 (11.1%), 2 (22.2%), and 5 (55.6%) cases were identified as C. tropicalis, C. membranifaciens, C. glabrata, and C. albicans, respectively, using the internal transcribed spacer region sequencing. Furthermore, the four yeasts isolated from the blood culture included C. tropicalis, C. carpophila, C. membranifaciens, and Cryptococcus albidus. Additionally, one case of C. glabrata and one case of C. albicans were isolated from the skin culture of the catheter insertion areas in patients with positive catheter culture. We reported two cases of catheter-related candidemia caused by C. membranifaciens and C. tropicalis on the basis of the genetic similarity of the species isolated from the blood and catheter. These cases were treated successfully with intravenous fluconazole and catheter removal.

Conclusion

There is some evidence indicating the growing prevalence of non-albicans Candida infections. Many risk factors, including prior antibiotic therapy, use of a central venous catheter, surgery, and parenteral nutrition, are considered to be associated with candidemia in hospitalized heart failure patients. The identification of the route of infection in candidemia is difficult. In the current study, the positive blood and catheter cultures for Candida isolates and the similarity of the ITS region of ribosomal DNA sequence of Candida isolated from two patients confirmed the diagnosis of intravenous catheter-related candidemia.

Neonatal and Pediatric Candidemia: Results From Population-Based Active Laboratory Surveillance in Four US Locations, 2009-2015

INTRODUCTION

Candida is a leading cause of healthcare-associated bloodstream infections in the United States. Infants and children have unique risk factors for candidemia, and the Candida species distribution in this group is different that among adults; however, candidemia epidemiology in this population has not been described recently.

METHODS

We conducted active population-based candidemia surveillance in 4 US metropolitan areas between 2009 and 2015. We calculated incidences among neonates (0-30 days old), infants (0-364 days old), and noninfant children (1-19 years old), documented their clinical features and antifungal drug resistance.

RESULTS

We identified 307 pediatric candidemia cases. Incidence trends varied according to site, but overall, the incidence in neonates decreased from 31.5 cases/100000 births in 2009 to 10.7 to 11.8 cases/100000 births between 2012 and 2015, the incidence in infants decreased from 52.1 cases/100000 in 2009 to 15.7 to 17.5 between 2012 and 2015, and the incidence in noninfant children decreased steadily from 1.8 cases/100000 in 2009 to 0.8 in 2014. Common underlying conditions were prematurity in neonates (78%), surgery in nonneonate infants (38%), and malignancy in noninfant children (28%). Most neonate cases were caused by C albicans (67%), whereas non-C. albicans species accounted for 60% of cases in nonneonate infants and noninfant children. Fluconazole and echinocandin resistance rates were low overall. Thirty-day crude mortality was 13%.

CONCLUSIONS

The incidence of candidemia among neonates and infants declined after 2009 but remained stable from 2012 to 2015. Antifungal drug resistance is uncommon. Reasons for the lack of recent declines in neonatal and infant candidemia deserve further exploration. In this article, we describe the epidemiology of candidemia in children in the United States and on the basis of data collected as part of US Centers for Disease Control and Prevention active population-based surveillance. Trends in incidence, clinical characteristics, species distribution, and resistance rates are presented.

Relative Abundances of Candida albicans and Candida glabrata in In Vitro Coculture Biofilms Impact Biofilm Structure and Formation

Candida is a member of the normal human microbiota and often resides on mucosal surfaces such as the oral cavity or the gastrointestinal tract. In addition to their commensality, Candida species can opportunistically become pathogenic if the host microbiota is disrupted or if the host immune system becomes compromised. An important factor for Candida pathogenesis is its ability to form biofilm communities. The two most medically important species-Candida albicans and Candida glabrata-are often coisolated from infection sites, suggesting the importance of Candida coculture biofilms. In this work, we report that biofilm formation of the coculture population depends on the relative ratio of starting cell concentrations of C. albicans and C. glabrata When using a starting ratio of C. albicans to C. glabrata of 1:3, ∼6.5- and ∼2.5-fold increases in biofilm biomass were observed relative to those of a C. albicans monoculture and a C. albicans/C. glabrata ratio of 1:1, respectively. Confocal microscopy analysis revealed the heterogeneity and complex structures composed of long C. albicans hyphae and C. glabrata cell clusters in the coculture biofilms, and reverse transcription-quantitative PCR (qRT-PCR) studies showed increases in the relative expression of the HWP1 and ALS3 adhesion genes in the C. albicans/C. glabrata 1:3 biofilm compared to that in the C. albicans monoculture biofilm. Additionally, only the 1:3 C. albicans/C. glabrata biofilm demonstrated an increased resistance to the antifungal drug caspofungin. Overall, the results suggest that interspecific interactions between these two fungal pathogens increase biofilm formation and virulence-related gene expression in a coculture composition-dependent manner.IMPORTANCECandida albicans and Candida glabrata are often coisolated during infection, and the occurrence of coisolation increases with increasing inflammation, suggesting possible synergistic interactions between the two Candida species in pathogenesis. During the course of an infection, the prevalence of each Candida species may change over time due to differences in metabolism and in the resistance of each species to antifungal therapies. Therefore, it is necessary to understand the dynamics between C. albicans and C. glabrata in coculture to develop better therapeutic strategies against Candida infections. Existing in vitro work has focused on understanding how an equal-part culture of C. albicans and C. glabrata impacts biofilm formation and pathogenesis. What is not understood, and what is investigated in this work, is how the composition of Candida species in coculture impacts overall biofilm formation, virulence gene expression, and the therapeutic treatment of biofilms.

Antifungal susceptibility testing results of New Zealand yeast isolates, 2001-2015: Impact of recent CLSI breakpoints and epidemiological cut-off values for Candida and other yeast species

OBJECTIVES

We reviewed the antifungal susceptibility testing results of local yeast isolates (2001-2015) to record the impact of recently updated interpretive criteria and epidemiological cut-off values (ECVs) for yeast species.

METHODS

Susceptibility testing was performed using Sensititre^® YeastOne^®. The results were interpreted following CLSI criteria or YeastOne-derived ECVs.

RESULTS

A total of 2345 isolates were tested; 62.0% were from sterile body sites or tissue. Application of new CLSI interpretative criteria for fluconazole increased the proportion of non-susceptible isolates of Candida parapsilosis, Candida tropicalis and Candida glabrata (P≤0.03 for all species). For voriconazole, the greatest increase was for C. tropicalis (P<0.0001). Application of new CLSI interpretive criteria for caspofungin increased the proportion of non-susceptible isolates for C. glabrata and Pichia kudriavzevii (P<0.0001 for both). The new amphotericin ECV (≤2mg/L) did not reveal any non-wild-type (non-WT) isolates in the five species covered. YeastOne itraconazole ECVs detected 2%, 5% and 6% non-WT isolates for P. kudriavzevii, C. tropicalis and C. glabrata, respectively. No itraconazole non-WT isolates of Clavispora lusitaniae were detected.

CONCLUSIONS

Whilst most results are similar to other large surveys of fungal susceptibility, the new CLSI interpretive criteria significantly altered the proportion of non-susceptible isolates to fluconazole, voriconazole and caspofungin for several Candida spp. Application of CLSI and YeastOne-derived ECVs revealed the presence of a low proportion of non-WT isolates for many species. The results serve as a baseline to monitor the susceptibility of Candida and other yeast species in New Zealand over time.

Chemical composition, antioxidant activity and antifungal effects of five Iranian essential oils against Candida strains isolated from urine samples

Systemic candidiasis has become an emerging fungal infection in recent years. Anti-Candida resistance to conventional antifungal agents has subsequently increased. This study reported the chemical composition, antioxidant and anti-Candida activity of Origanum majorana, Artemisia dracunculus, Cymbopogon citrate, Cinnamomum verum and Caryophyllus aromaticus essential oils. Different Candida species, from urine tracts of hospitalized patients, were included to be challenged with understudied essential oils. Chemical compositions were determined using gas chromatography/mass spectroscopy (GC/MS) analysis and antioxidant activity was measured using DDPH assay. MIC of these essential oils was evaluated using broth micro-dilution test. Caryophyllus aromaticus had the highest antioxidant activity while the lowest antioxidant activity was for Artemisia dracunculus. MICs of Cinnamomum verum, Caryophillium aromaticus, Artemisia dracunculus, Origanum vulgare and Cymbopogon citratus essential oils ranged from 125 to 175μg/mL (mean value: 147.7±25.5μg/mL), 700 to 1000μg/mL (mean value: 740.9±105.4μg/mL), 1000 to 2000μg/mL (mean value: 1454.5±509.6μg/mL), 173 to 350μg/mL (mean value: 208±55.8μg/mL) and 125 to 175μg/mL (mean value: 156.8±24.6μg/mL) for different Candida species, respectively. In general, natural compounds are suitable to be used as anti-Candida and antioxidant agents. However in this stage, these compounds could be applied as supplementary agents along with conventional antifungal drugs.

Pharmacodynamic studies of voriconazole: informing the clinical management of invasive fungal infections

INTRODUCTION

Voriconazole is a broad-spectrum antifungal agent commonly used to treat invasive fungal infections (IFI), including aspergillosis, candidiasis, Scedosporium infection, and Fusarium infection. IFI often occur in immunocompromised patients, leading to increased morbidity and mortality.

AREAS COVERED

The objective of this review is to summarize the pharmacodynamic properties of voriconazole and to provide considerations for potential optimal dosing strategies. Studies have demonstrated superior clinical response when an AUC/MIC >25 or Cmin/MIC >1 is attained in adult patients, correlating to a trough concentration range as narrow as 2-4.5 mg/L; however, these targets are poorly established in the pediatric population. Topics in this discussion include voriconazole use in multiple age groups, predisposing patient factors for IFI, and considerations for clinicians managing IFI. Expert commentary: The relationship between voriconazole dosing and exposure is not well defined due to the large inter- and intra-subject variability. Development of comprehensive decision support tools for individualizing dosing, particularly in children who require higher dosing, will help to increase the probability of achieving therapeutic efficacy and decrease sub-therapeutic dosing and adverse events.

Oral mycoses and other opportunistic infections in HIV: therapy and emerging problems - a workshop report

Oral mycoses and other opportunistic infections are recognized features of HIV infection even after four decades of the epidemic. The therapeutic options, challenges of therapy, and evolving patterns of opportunistic infections were evaluated by the workshop. It was observed that high Candida counts and infection are still more prevalent in HIV-positive individuals even in the era of antiretroviral therapy. Furthermore, one or more non-Candida albicans are present in some HIV-positive individuals. While Candida species are more virulent in HIV infection, similar virulence may be present in other states of immunosuppression. Consequently, the interplay between host factors and virulence ultimately determines the clinical outcomes. Adverse clinical outcomes such as candidemia and other deep fungal infections are on the increase in HIV infection. Disseminated histoplasmosis and penicilliosis have been reported, especially with low CD4 counts. Even with advances in antifungal therapy, mortality and morbidity from deep fungal infections have not changed significantly. In addition, long-term exposure to common antifungal drugs such as fluconazole has led to the development of antifungal resistance in 6% to 36%. Development of new antifungal therapeutic agents and the use of alternative therapies may offer breakthrough. In addition, effective strategies to enhance the host immune status are being explored.

Candida glabrata Biofilms: How Far Have We Come?

Infections caused by Candida species have been increasing in the last decades and can result in local or systemic infections, with high morbidity and mortality. After Candida albicans, Candida glabrata is one of the most prevalent pathogenic fungi in humans. In addition to the high antifungal drugs resistance and inability to form hyphae or secret hydrolases, C. glabrata retain many virulence factors that contribute to its extreme aggressiveness and result in a low therapeutic response and serious recurrent candidiasis, particularly biofilm formation ability. For their extraordinary organization, especially regarding the complex structure of the matrix, biofilms are very resistant to antifungal treatments. Thus, new approaches to the treatment of C. glabrata’s biofilms are emerging. In this article, the knowledge available on C. glabrata’s resistance will be highlighted, with a special focus on biofilms, as well as new therapeutic alternatives to control them.

Oral candidal speciation, virulence and antifungal susceptibility in type 2 diabetes mellitus

OBJECTIVES

To determine the oral candidal carriage (OCC), activity of virulent factors and fluconazole susceptibility in subjects with type 2 diabetes mellitus (T2DM) and investigate their association with HbA1c measurements.

MATERIALS AND METHODS

A cross sectional study was conducted on 100 diabetics and 100 healthy volunteers. The virulence was assessed by measuring the phospholipase activity and proteolysis index. Fluconazole susceptibility was performed using the gradient diffusion method. The OCC, virulence factors and antifungal susceptibility were correlated with patients' HbA1c measurements.

RESULTS

The OCC and candidal density carriage was significantly higher in diabetics. Candida albicans (C. albicans) was the most frequently isolated species followed by Candida tropicalis (C. tropicalis). Relatively uncommon species, Candida lusitaniae (C. lusitaniae) and Candida lipolytica (C. lipolytica) were isolated from the diabetics. Prevalence of virulence factor, proteinase, was greater in diabetic group (p<0.05). Reduced fluconazole susceptibility was noted among the isolates from diabetics; however it was not statistically significant (p=0.593). Except one, all the susceptible-dose dependent and resistant isolates were Candida no-albicans (C. non-albicans).

CONCLUSION

C. albicans remains the predominant pathogen in diabetics, although other species are on the rise. Compared to control group, the isolated species from T2DM group had higher proteinase activity. Resistance to fluconazole was considerably greater among the C. non-albicans isolates from T2DM group. These findings warrant effective treatment modalities to reduce the occurrence of oropharyngeal candidiasis.

Nanoparticle-Based Mycosis Vaccine

Many diseases that were considered major affliction of mankind in the past have been successfully eradicated with introduction of appropriate vaccine strategies. In order to expedite new challenges coming up to deal with various infectious diseases, nano-particulate-based subunit vaccines seem to be the demand of ordeal. The nano-vaccines can find better scope for the diseases that were not rampant in the semi-advanced world few years back. For example in present-day circumstances that corroborate with advancement in the field of medical sciences in terms of cancer chemotherapy, organ transplantation, therapy of autoimmune diseases, etc.; along with prevalence of altogether unheard diseases such as HIV infection, people are at risk of infliction with many more pathogens. In this regard, development of an effective prophylactic strategy against many opportunistic infections primarily caused by fungal pathogens needs better understanding of host pathogen relation and role of active immunity against pathogenic fungi. In the present study, we have tried to decipher effectiveness of a nano-sized vaccine delivery system in imparting protection against fungal pathogens.

Enhanced candicidal compound production by a new soil isolate Penicillium verruculosum MKH7 under submerged fermentation

BACKGROUND

Microorganisms are a rich source of structurally diverse secondary metabolites that exert a major impact on the control of infectious diseases and other medical conditions. The biosynthesis of these metabolites can be improved by manipulating the nutritional or environmental factors. This work evaluates the effects of fermentation parameters on the production of a lactone compound effective against Candida albicans by Penicillium verruculosum MKH7 under submerged fermentation. Design-Expert version8.0 software was used for construction of the experimental design and statistical analysis of the experimental data.

RESULTS

The important factors influencing antibiotic production selected in accordance with the Plackett-Burman design were found to be initial pH, temperature, peptone, MgSO4.7H2O. Orthogonal central composite design and response surface methodology were adopted to further investigate the mutual interaction between the variables and identify the optimum values that catalyse maximum metabolite production. The determination coefficient (R2) of the fitted second order model was 0.9852. The validation experiments using optimized conditions of initial pH 7.4, temperature 27 °C, peptone 9.2 g/l and MgSO4.7H2O 0.39 g/l resulted in a significant increase (almost 7 fold from 30 to 205.5 mg/l) in the metabolite production which was in agreement with the prediction (211.24 mg/l). Stability of the compound was also assessed on the basis of its response to physical and chemical stresses.

CONCLUSIONS

So far as our knowledge goes, till date there are no reports available on the production of antibiotics by Penicillium verruculosum through media optimization using RSM. Optimization not only led to a 7 fold increase in metabolite yield but the same was achieved at much lesser time (8-10 days compared to the earlier 12-15 days). The enhanced yield of the antibiotic strongly suggests that the fungus P. verruculosum MKH7 can be efficiently used for antibiotic production on a large scale.

The epidemiology and outcomes of invasive Candida infections among organ transplant recipients in the United States: results of the Transplant-Associated Infection Surveillance Network (TRANSNET)

BACKGROUND

Invasive candidiasis (IC) is a common cause of mortality in solid organ transplant recipients (OTRs), but knowledge of epidemiology in this population is limited.

METHOD

The present analysis describes data from 15 US centers that prospectively identified IC from nearly 17 000 OTRs. Analyses were undertaken to determine predictors of infection and mortality.

RESULTS

A total of 639 cases of IC were identified. The most common species was Candida albicans (46.3%), followed by Candida glabrata (24.4%) and Candida parapsilosis (8.1%). In 68 cases >1 species was identified. The most common infection site was bloodstream (44%), followed by intra-abdominal (14%). The most frequently affected allograft groups were liver (41.1%) and kidney (35.3%). All-cause mortality at 90 days was 26.5% for all species and was highest for Candida tropicalis (44%) and C. parapsilosis (35.2%). Non-white race and female gender were more commonly associated with non-albicans species. A high rate of breakthrough IC was seen in patients receiving antifungal prophylaxis (39%). Factors associated with mortality include organ dysfunction, lung transplant, and treatment with a polyene antifungal. The only modifiable factor identified was choice of antifungal drug class based upon infecting Candida species.

CONCLUSION

These data highlight the common and distinct features of IC in OTRs.

Coumarin Antifungal Lead Compounds from Millettia thonningii and Their Predicted Mechanism of Action

Fungal pathogens continue to pose challenges to humans and plants despite efforts to control them. Two coumarins, robustic acid and thonningine-C isolated from Millettia thonningii, show promising activity against the fungus Candida albicans with minimum fungicidal concentration of 1.0 and 0.5 mg/mL, respectively. Molecular modelling against the putative bio-molecular target, lanosterol 14α-demethylase (CYP51), revealed a plausible binding mode for the active compounds, in which the hydroxyl group binds with a methionine backbone carboxylic group blocking access to the iron catalytic site. This binding disrupts the synthesis of several important sterols for the survival of fungi.

Pharmacological evaluation of poly(3-methylthiophene) and its titanium(IV)phosphate nanocomposite: DNA interaction, molecular docking, and cytotoxic activity

Cancer and pathogenic microbial diseases have terribly affected human health over a longer period of time. In response to the increasing casualties due to cancer and microbial diseases, unique poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate composite were prepared via in-situ oxidative chemical polymerization in this work. The poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate composite were well characterized by Fourier transform infrared spectroscopy and field emission scanning electron microscopy. DNA binding studies by UV-Visible and fluorescence spectroscopic investigations indicated strong binding affinities of poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite; leading to structural damage of DNA. Poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite showed stronger interactions with DNA as compared to poly(3-methylthiophene) and from dye displacement assay it was confirmed that mode of binding of both the formulations was intercalative. The antimicrobial screening revealed that polymer and its composite displayed stronger antibacterial effects than ampicillin against Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella typhimurium. Besides, the poly(3-methylthiophene) and poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite showed dose dependent effects towards estrogen receptor positive breast cancer (MCF-7) and estrogen receptor negative breast cancer (MDA-MB-231) cell lines; with poly(3-methylthiophene)-titanium(IV)phosphate nanocomposite showing better activities against both cell lines. In all in-vitro biological investigations, poly(3-methylthiophene)-titanium(IV)phosphate composite showed superior properties to that of the pure poly(3-methylthiophene), which encouraged us to suggest its potential as future therapeutic gear in drug delivery and other allied fields.