Invasive fungal infections among organ transplant recipients: results of the Transplant-Associated Infection Surveillance Network (TRANSNET)

Burden of serious fungal infections in Mexico

Serious fungal infections (SFIs) could be more frequent than are recognised. Estimates of the incidence and prevalence of SFIs are essential in order to identify public health problems. We estimated the rates of SFIs in Mexico, following a methodology similar to that used in prior studies. We obtained information about the general population and populations at risk. A systematic literature search was undertaken to identify epidemiological reports of SFIs in Mexico. When Mexican reports were unavailable, we based our estimates on international literature. The most prevalent SFIs in Mexico are recurrent vulvovaginal candidiasis (5999 per 100,000) followed by allergic bronchopulmonary aspergillosis (60 per 100,000), chronic pulmonary aspergillosis (15.9 per 100,000), fungal keratitis (10.4 per 100,000), invasive candidiasis (8.6 per 100,000) and SFIs in HIV (8.2 per 100,000); coccidioidomycosis (7.6 per 100,000), IA (4.56 per 100,000). These correspond to 2,749,159 people affected in any year (2.45% of the population), probably >10,000 deaths and 7000 blind eyes. SFIs affect immunocompromised and healthy populations. Most are associated with high morbidity and mortality rates. Validation of these estimates with epidemiological studies is required. The burdens indicate that an urgent need to improve medical skills, surveillance, diagnosis, and management of SFIs exists.

Pharmacokinetic and Pharmacodynamic Evaluation of the Drug-Drug Interaction Between Isavuconazole and Warfarin in Healthy Subjects

This phase 1 trial evaluated pharmacokinetic and pharmacodynamic interactions between the novel triazole antifungal agent isavuconazole and warfarin in healthy adults. Multiple doses of isavuconazole were administered as the oral prodrug, isavuconazonium sulfate (372 mg 3 times a day for 2 days loading dose, then 372 mg once daily thereafter; equivalent to isavuconazole 200 mg), in the presence and absence of single doses of oral warfarin sodium 20 mg. Coadministration with isavuconazole increased the mean area under the plasma concentration‐time curves from time 0 to infinity of S‐ and R‐warfarin by 11% and 20%, respectively, but decreased the mean maximum plasma concentrations of S‐ and R‐warfarin by 12% and 7%, respectively, relative to warfarin alone. Mean area under the international normalized ratio curve and maximum international normalized ratio were 4% lower in the presence vs absence of isavuconazole. Mean warfarin area under the prothrombin time curve and maximum prothrombin time were 3% lower in the presence vs absence of isavuconazole. There were no serious treatment‐emergent adverse events (TEAEs), and no subjects discontinued the study due to TEAEs. All TEAEs were mild in intensity. These findings indicate that coadministration with isavuconazole has no clinically relevant effects on warfarin pharmacokinetics or pharmacodynamics.

Estimated burden of fungal infections in Germany

In the late 1980's, the incidence of invasive fungal diseases (IFDs) in Germany was estimated with 36.000 IFDs per year. The current number of fungal infections (FI) occurring each year in Germany is still not known. In the actual analysis, data on incidence of fungal infections in various patients groups at risk for FI were calculated and mostly estimated from various (mostly national) resources. According to the very heterogenous data resources robust data or statistics could not be obtained but preliminary estimations could be made and compared with data from other areas in the world using a deterministic model that has consistently been applied in many countries by the LIFE program ( www.LIFE-worldwide.org). In 2012, of the 80.52 million population (adults 64.47 million; 41.14 million female, 39.38 million male), 20% are children (0-14 years) and 16% of population are ≥65 years old. Using local data and literature estimates of the incidence or prevalence of fungal infections, about 9.6 million (12%) people in Germany suffer from a fungal infection each year. These figures are dominated (95%) by fungal skin disease and recurrent vulvo-vaginal candidosis. In general, considerable uncertainty surrounds the total numbers because IFDs do not belong to the list of reportable infectious diseases in Germany and most patients were not hospitalised because of the IFD but a distinct underlying disease.

Burden of serious fungal diseases in Hungary

Valid data on the prevalence of serious fungal diseases are difficult to derive as in most countries these conditions are not reportable infections. To assess the burden of these infections in Hungary prevalence estimates from international peer-reviewed papers and population statistics were utilised. In the intensive care unit (ICU) population at least 370 cases of serious yeast and 52 mould infections can be expected yearly. The total number of candidaemia cases may be as high as 1110 annually. In patients with acute leukaemia and recipients of haematopoietic stem cell and solid organ transplants the predicted incidence is more than 55 every year. Recurrent vulvovaginal candidiasis--though not a life-threatening condition--can adversely affect the quality of life of more than 177,000 Hungarian women. According to organisation for economic co-operation and development (OECD), 4.7% of total population older than 15 will suffer from chronic obstructive pulmonary disease (COPD) and 4.4% from asthma, adding another very broad risk group to the aforementioned categories susceptible for mycotic complications. Here more than 17,000 can have severe asthma with fungal sensitisation (SAFS) and more than 13,000 are at risk for developing allergic bronchopulmonary aspergillosis (ABPA). The incidence of dermatomycoses and other superficial fungal infections is even more difficult to assess but--according to international estimations--can affect around 14.3% of the total population. More than 1.6 million Hungarians may suffer from fungal diseases annually, with 33,000 cases being life threatening or very serious. This is an under-recognised problem of special importance for public health.

Antifungal prophylaxis in liver transplant recipients: one size does not fit all

BACKGROUND

Targeted antifungal prophylaxis against Candida species or against Candida species and Aspergillus species, according to individual patient risk factors (RFs), is recommended by experts. However, recent studies have reported fluconazole is as effective as broader spectrum antifungals for preventing invasive fungal infection (IFI) after liver transplantation (LT).

METHODS

We performed a retrospective cohort study of all adult patients who underwent LT at our 1420-bed tertiary teaching hospital, from June 2010 to December 2014, to assess the rate and etiology of IFI within 100 days after LT, to investigate the compliance with targeted prophylaxis, and to analyze risk factors for developing IFI.

RESULTS

In total, 303 patients underwent LT. Patients were classified as having low (no RFs), intermediate (1 RF for invasive candidiasis [IC]), and high risk (1 RF for invasive aspergillosis [IA] or ≥2 RFs for IC) for IFI in 20%, 30%, and 50% of cases, respectively. A total of 139 patients received antifungal prophylaxis: 98 with a mold-active drug and 41 with fluconazole. Overall adherence to targeted prophylaxis was 53%. Nineteen patients (6.3%) developed IFI: 7 IC and 12 IA. Multivariate Cox regression analysis, adjusted for median model for end-stage liver disease score at LT, stratification risk group, and adherence to targeted prophylaxis, showed that graft dysfunction, renal replacement therapy, and prophylaxis with fluconazole were independent risk factors for IFI. Seven of the 9 patients who received fluconazole prophylaxis and developed IFI were classified as having high risk for IFI, and 6 developed IA.

CONCLUSION

Recommended stratification is accurate for predicting patients at very high risk for IFI, who should receive prophylaxis with a mold-active drug.

Risk factors, clinical presentation and prognosis of mixed candidaemia: a population-based surveillance in Spain

The low incidence of mixed candidaemia (MC) may have precluded a better knowledge of its clinical presentation. The aim of the study was to analyse the risk factors, clinical presentation and prognosis of MC episodes. A comparison between MC and monomicrobial candidaemia within a prospective programme on candidaemia was performed in 29 hospitals between April 2010 and May 2011. In fifteen episodes of candidaemia corresponding to 15 patients, out of 752, two species of Candida (1.9%) were isolated. MC was more frequent in patients with HIV infection (12%, P = 0.038) and those admitted due to extensive burns (23%, P = 0.012). The Candida species most frequently identified in MC were C. albicans 12 patients (40%), C. glabrata seven patients (23.3%) and C. parapsilosis six patients (20%). Early mortality was higher (nine patients, 60%) in patients with MC than in patients with MMC (223 patients, 30.3%, P = 0.046). In conclusion, MC was was independently associated with increased mortality even after considering other prognostic factors. MC is an infrequent event that is more common in HIV infection and in patients suffering from burns, and is associated with increased mortality.

Pharmacokinetic Interactions Between Isavuconazole and the Drug Transporter Substrates Atorvastatin, Digoxin, Metformin, and Methotrexate in Healthy Subjects

This article summarizes 4 phase 1 trials that explored interactions between the novel, triazole antifungal isavuconazole and substrates of the drug transporters breast cancer resistance protein (BCRP), multidrug and toxin extrusion protein‐1 (MATE1), organic anion transporters 1/3 (OAT1/OAT3), organic anion‐transporting polypeptide 1B1 (OATP1B1), organic cation transporters 1/2 (OCT1/OCT2), and P‐glycoprotein (P‐gp). Healthy subjects received single doses of atorvastatin (20 mg; OATP1B1 and P‐gp substrate), digoxin (0.5 mg; P‐gp substrate), metformin (850 mg; OCT1, OCT2, and MATE1 substrate), or methotrexate (7.5 mg; BCRP, OAT1, and OAT3 substrate) in the presence and absence of clinical doses of isavuconazole (200 mg 3 times a day for 2 days; 200 mg once daily thereafter). Coadministration with isavuconazole increased mean area under the plasma concentration‐time curves (90% confidence interval) of atorvastatin, digoxin, and metformin to 137% (129, 145), 125% (117, 134),  and 152% (138, 168) and increased mean maximum plasma concentrations to 103% (88, 121), 133% (119, 149), and 123% (109, 140), respectively. Methotrexate parameters were unaffected by isavuconazole. There were no serious adverse events. These findings indicate that isavuconazole is a weak inhibitor of P‐gp, as well as OCT1, OCT2, MATE1, or a combination thereof but not of BCRP, OATP1B1, OAT1, or OAT3.

Identification by Molecular Methods and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry and Antifungal Susceptibility Profiles of Clinically Significant Rare Aspergillus Species in a Referral Chest Hospital in Delhi, India

Aspergillus species cause a wide spectrum of clinical infections. Although Aspergillus fumigatus and Aspergillus flavus remain the most commonly isolated species in aspergillosis, in the last decade, rare and cryptic Aspergillus species have emerged in diverse clinical settings. The present study analyzed the distribution and in vitro antifungal susceptibility profiles of rare Aspergillus species in clinical samples from patients with suspected aspergillosis in 8 medical centers in India. Further, a matrix-assisted laser desorption ionization-time of flight mass spectrometry in-house database was developed to identify these clinically relevant Aspergillus species. β-Tubulin and calmodulin gene sequencing identified 45 rare Aspergillus isolates to the species level, except for a solitary isolate. They included 23 less common Aspergillus species belonging to 12 sections, mainly in Circumdati, Nidulantes, Flavi, Terrei, Versicolores, Aspergillus, and Nigri Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) identified only 8 (38%) of the 23 rare Aspergillus isolates to the species level. Following the creation of an in-house database with the remaining 14 species not available in the Bruker database, the MALDI-TOF MS identification rate increased to 95%. Overall, high MICs of ≥2 μg/ml were noted for amphotericin B in 29% of the rare Aspergillus species, followed by voriconazole in 20% and isavuconazole in 7%, whereas MICs of >0.5 μg/ml for posaconazole were observed in 15% of the isolates. Regarding the clinical diagnoses in 45 patients with positive rare Aspergillus species cultures, 19 (42%) were regarded to represent colonization. In the remaining 26 patients, rare Aspergillus species were the etiologic agent of invasive, chronic, and allergic bronchopulmonary aspergillosis, allergic fungal rhinosinusitis, keratitis, and mycetoma.

Identification of Components of the SUMOylation Machinery in Candida glabrata: ROLE OF THE DESUMOYLATION PEPTIDASE CgUlp2 IN VIRULENCE

Regulation of protein function by reversible post-translational modification, SUMOylation, is widely conserved in the eukaryotic kingdom. SUMOylation is essential for cell growth, division, and adaptation to stress in most organisms, including fungi. As these are key factors in determination of fungal virulence, in this study, we have investigated the importance of SUMOylation in the human pathogen, Candida glabrata We identified the enzymes involved in small ubiquitin-like modifier conjugation and show that there is strong conservation between Saccharomyces cerevisiae and C. glabrata We demonstrate that SUMOylation is an essential process and that adaptation to stress involves changes in global SUMOylation in C. glabrata Importantly, loss of the deSUMOylating enzyme CgUlp2 leads to highly reduced small ubiquitin-like modifier protein levels, and impaired growth, sensitivity to multiple stress conditions, reduced adherence to epithelial cells, and poor colonization of specific tissues in mice. Our study thus demonstrates a key role for protein SUMOylation in the life cycle and pathobiology of C. glabrata.

Galactomannan and 1,3-β-d-Glucan Testing for the Diagnosis of Invasive Aspergillosis

Invasive aspergillosis (IA) is a severe complication among hematopoietic stem cell transplant recipients or patients with hematological malignancies and neutropenia following anti-cancer therapy. Moreover, IA is increasingly observed in other populations, such as solid-organ transplant recipients, patients with solid tumors or auto-immune diseases, and among intensive care unit patients. Frequent delay in diagnosis is associated with high mortality rates. Cultures from clinical specimens remain sterile in many cases and the diagnosis of IA often only relies on non-specific radiological signs in the presence of host risk factors. Tests for detection of galactomannan- (GM) and 1,3-β-d-glucan (BDG) are useful adjunctive tools for the early diagnosis of IA and may have a role in monitoring response to therapy. However, the sensitivity and specificity of these fungal biomarkers are not optimal and variations between patient populations are observed. This review discusses the role and interpretation of GM and BDG testing for the diagnosis of IA in different clinical samples (serum, bronchoalveolar lavage fluid, cerebrospinal fluid) and different groups of patients (onco-hematological patients, solid-organ transplant recipients, other patients at risk of IA).

Risk Factors Associated With Early Invasive Pulmonary Aspergillosis in Kidney Transplant Recipients: Results From a Multinational Matched Case-Control Study

Risk factors for invasive pulmonary aspergillosis (IPA) after kidney transplantation have been poorly explored. We performed a multinational case-control study that included 51 kidney transplant (KT) recipients diagnosed with early (first 180 posttransplant days) IPA at 19 institutions between 2000 and 2013. Control recipients were matched (1:1 ratio) by center and date of transplantation. Overall mortality among cases was 60.8%, and 25.0% of living recipients experienced graft loss. Pretransplant diagnosis of chronic pulmonary obstructive disease (COPD; odds ratio [OR]: 9.96; 95% confidence interval [CI]: 1.09-90.58; p = 0.041) and delayed graft function (OR: 3.40; 95% CI: 1.08-10.73; p = 0.037) were identified as independent risk factors for IPA among those variables already available in the immediate peritransplant period. The development of bloodstream infection (OR: 18.76; 95% CI: 1.04-339.37; p = 0.047) and acute graft rejection (OR: 40.73, 95% CI: 3.63-456.98; p = 0.003) within the 3 mo prior to the diagnosis of IPA acted as risk factors during the subsequent period. In conclusion, pretransplant COPD, impaired graft function and the occurrence of serious posttransplant infections may be useful to identify KT recipients at the highest risk of early IPA. Future studies should explore the potential benefit of antimold prophylaxis in this group.

Prognosis of Invasive Aspergillosis in Kidney Transplant Recipients: A Case-Control Study

BACKGROUND

Invasive aspergillosis (IA) is a major cause of invasive fungal infection in kidney transplant recipients (KTR), and it has a high mortality rate. However, its impact on patients and graft survival has not been well defined in the current era of voriconazole first-line therapy.

METHODS

We retrospectively collected all cases of KTR-associated IA occurring at Necker Enfants Malades Hospital, Paris, from 2003 to 2013. These cases were compared with a group of controls (1:3) who were matched by age, year of kidney transplantation, and sex. The characteristics of IA were also studied.

RESULTS

Sixteen patients developed IA after KTR. Most IA cases were limited to the lungs (81.3%), with mild respiratory symptoms in only 53% of the patients. The patients were administered voriconazole (n = 15, 94%) and/or posaconazole (n = 2, 13%). The 12-week and 1-year postinfection survival rates were 94% and 81%, respectively. Compared with the controls (n = 46), patients and death-censored graft survivals rates were significantly lower after IA (P = 0.017 and 0.001, respectively). In the patients with IA, the occurrences of cardiovascular diseases before transplantation (P < 0.0001), delayed graft function (P < 0.0001), and infectious complications (0.0018) were significantly more frequent.

CONCLUSIONS

Even with voriconazole therapy, the prognosis of patients with IA after kidney transplantation is still poor. When the patients survive to IA, they have a high risk of graft loss.

Hospital resource use of patients receiving isavuconazole vs voriconazole for invasive mold infections in the phase III SECURE trial

OBJECTIVE

In the phase III SECURE trial, isavuconazole was non-inferior to voriconazole for all-cause mortality for the primary treatment of invasive mold disease (IMD) caused by Aspergillus spp. and other filamentous fungi. This analysis assessed whether hospital resource utilization was different between patients treated with isavuconazole vs voriconazole in SECURE.

METHODS

The analysis population comprised adults with proven/probable/possible IMD enrolled in SECURE. The primary endpoint was hospital length of stay (LOS) in the overall trial population. Patients were also stratified by estimated glomerular filtration rate-modification of diet in renal disease category (< 60 mL/min/1.73 m(2) [moderate-to-severe impairment] and ≥60 mL/min/1.73 m(2) [mild or no impairment]), body mass index (BMI; <25, ≥25-<30, and ≥30 kg/m(2)), and age (≤45, >45-≤65, and >65 years).

RESULTS

Data from 516 patients (258 per arm) were evaluated. Overall, median LOS was not statistically significantly different between the isavuconazole (15.0 days) and voriconazole (16.0 days; p = 0.607) arms. Median LOS was statistically significantly shorter in patients with moderate-to-severe renal impairment treated with isavuconazole (9.0 days) vs voriconazole (19.0 days; hazard ratio [HR]: 3.44; 95% confidence interval [CI] = 1.51-7.83). Median LOS was shorter, but not significantly, in patients with a BMI ≥30 kg/m(2) (isavuconazole 13.5 days vs voriconazole 22 days; HR = 1.57; 95% CI = 0.70-3.52) or aged >65 years (isavuconazole 15.0 days vs voriconazole 20.0 days; HR = 1.37; 95% CI = 0.87-2.16).

LIMITATIONS

As the patient subgroups analyzed were small, sub-group findings should be interpreted with caution in light of the lack of statistical significance for each sub-group-by-treatment interaction.

CONCLUSIONS

Isavuconazole may reduce hospital LOS in certain subgroups of patients with IMD, especially those with moderate-to-severe renal impairment.

Practice Guidelines for the Diagnosis and Management of Aspergillosis: 2016 Update by the Infectious Diseases Society of America

It is important to realize that guidelines cannot always account for individual variation among patients. They are not intended to supplant physician judgment with respect to particular patients or special clinical situations. IDSA considers adherence to these guidelines to be voluntary, with the ultimate determination regarding their application to be made by the physician in the light of each patient's individual circumstances.

Prospective Evaluation of Serum β-Glucan Testing in Patients With Probable or Proven Fungal Diseases

We evaluated the positivity of (1-3)-β-D-glucan, a serum marker of invasive fungal diseases (IFD), at diagnosis and during treatment. (1-3)-β-D-Glucan may not be an early marker but could prove useful for diagnosis of chronic IFD.

Background. Early diagnosis and treatment are crucial in invasive fungal diseases (IFD). Serum (1-3)-β-d-glucan (BG) is believed to be an early IFD marker, but its diagnostic performance has been ambiguous, with insufficient data regarding sensitivity at the time of IFD diagnosis (TOD) and according to outcome. Whether its clinical utility is equivalent for all types of IFD remains unknown.

Methods. We included 143 patients with proven or probable IFD (49 invasive candidiasis, 45 invasive aspergillosis [IA], and 49 rare IFD) and analyzed serum BG (Fungitell) at TOD and during treatment.

Results. (1-3)-β-d-glucan was undetectable at TOD in 36% and 48% of patients with candidemia and IA, respectively; there was no correlation between negative BG results at TOD and patients' characteristics, localization of infection, or prior antifungal use. Nevertheless, patients with candidemia due to Candida albicans were more likely to test positive for BG at TOD (odds ratio = 25.4, P = .01) than patients infected with other Candida species. In 70% of the patients with a follow-up, BG negativation occurred in >1 month for candidemia and >3 months for IA. A slower BG decrease in patients with candidemia was associated with deep-seated localizations (P = .04). Thirty-nine percent of patients with rare IFD had undetectable BG at TOD; nonetheless, all patients with chronic subcutaneous IFD tested positive at TOD.

Conclusions. Undetectable serum BG does not rule out an early IFD, when the clinical suspicion is high. After IFD diagnostic, kinetics of serum BG are difficult to relate to clinical outcome.

Pediatric Invasive Aspergillosis

Invasive aspergillosis (IA) is a disease of increasing importance in pediatrics due to growth of the immunocompromised populations at risk and improvements in long-term survival for many of these groups. While general principles of diagnosis and therapy apply similarly across the age spectrum, there are unique considerations for clinicians who care for children and adolescents with IA. This review will highlight important differences in the epidemiology, clinical manifestations, diagnosis, and therapy of pediatric IA.

Case of early-disseminated Rhizopus microsporus var. microsporus mucormycosis in a renal transplant patient

Mucormycosis is a rare infection caused by the ubiquitous filamentous fungi of the order Mucorales and class Zygomycetes. These species are vasotropic, causing rapid onset of tissue infarctions and necrosis and subsequent thrombosis by invading vascular bed. The disease spectrum ranges from involvement of skin, sinuses, lung, and brain to disseminated and mostly fatal infections, especially in immunocompromised hosts. Here, we present a case of a fatal disseminated mucormycosis in a 56-year-old female who had deceased donor renal allograft transplantation ~2 weeks prior to presentation. She presented with shortness of breath and dry cough. Despite being on broad-spectrum antibiotics/antifungals and proper management by transplant, infectious disease, and primary team, she died within 3 weeks of admission. Autopsy showed disseminated mucormycosis of lungs and thyroid. Disseminated infection within 2 weeks of solid organ transplantation in this patient was one of the rare features of mucormycosis.

Isavuconazole in the treatment of invasive aspergillosis and mucormycosis infections

We have a limited arsenal with which to treat invasive fungal infections caused by Aspergillus and Mucorales. The morbidity and mortality for both pathogens remains high. A triazole antifungal, isavuconazole, was recently granted approval by the US Food and Drug Administration and the European Medicines Agency for the treatment of invasive aspergillosis and mucormycosis. A randomized double-blind comparison trial for the treatment of invasive aspergillosis found isavuconazole noninferior to voriconazole. A separate, open-label study evaluating the efficacy of isavuconazole in the treatment of mucormycosis found comparable response rates to amphotericin B and posaconazole treated historical controls. The prodrug isavuconazonium sulfate is commercially available in both an oral and intravenous formulation and is generally well tolerated. Isavuconazole’s broad spectrum of activity, limited side effect profile, and favorable pharmacokinetics will likely solidify its place in therapy.

Cinnamaldehyde and its derivatives, a novel class of antifungal agents

The last few decades have seen an alarming rise in fungal infections, which currently represent a global health threat. Despite extensive research towards the development of new antifungal agents, only a limited number of antifungal drugs are available in the market. The routinely used polyene agents and many azole antifungals are associated with some common side effects such as severe hepatotoxicity and nephrotoxicity. Also, antifungal resistance continues to grow and evolve and complicate patient management, despite the introduction of new antifungal agents. This suitation requires continuous attention. Cinnamaldehyde has been reported to inhibit bacteria, yeasts, and filamentous molds via the inhibition of ATPases, cell wall biosynthesis, and alteration of membrane structure and integrity. In this regard, several novel cinnamaldehyde derivatives were synthesized with the claim of potential antifungal activities. The present article describes antifungal properties of cinnamaldehyde and its derivatives against diverse classes of pathogenic fungi. This review will provide an overview of what is currently known about the primary mode of action of cinnamaldehyde. Synergistic approaches for boosting the effectiveness of cinnamaldehyde and its derivatives have been highlighted. Also, a keen analysis of the pharmacologically active systems derived from cinnamaldehyde has been discussed. Finally, efforts were made to outline the future perspectives of cinnamaldehyde-based antifungal agents. The purpose of this review is to provide an overview of current knowledge about the antifungal properties and antifungal mode of action of cinnamaldehyde and its derivatives and to identify research avenues that can facilitate implementation of cinnamaldehyde as a natural antifungal.

Infectious Triggers of Chronic Lung Allograft Dysfunction

Survival after lung transplantation is limited in large part due to the high incidence of chronic rejection, known as chronic lung allograft dysfunction (CLAD). Pulmonary infections are a frequent complication in lung transplant recipients, due both to immunosuppressive medications and constant exposure of the lung allograft to the external environment via the airways. Infection is a recognized risk factor for the development of CLAD, and both acute infection and chronic lung allograft colonization with microorganisms increase the risk for CLAD. Acute infection by community acquired respiratory viruses, and the bacteria Pseudomonas aeruginosa and Staphylococcus aureus are increasingly recognized as important risk factors for CLAD. Colonization by the fungus Aspergillus may also augment the risk of CLAD. Fostering this transition from healthy lung to CLAD in each of these infectious episodes is the persistence of an inflammatory lung allograft environment.

Antifungal peptides: To be or not to be membrane active

Most antifungal peptides (AFPs), if not all, have membrane activity, while some also have alternative targets. Fungal membranes share many characteristics with mammalian membranes with only a few differences, such as differences in sphingolipids, phosphatidylinositol (PI) content and the main sterol is ergosterol. Fungal membranes are also more negative and a better target for cationic AFPs. Targeting just the fungal membrane lipids such as phosphatidylinositol and/or ergosterol by AFPs often translates into mammalian cell toxicity. Conversely, a specific AFP target in the fungal pathogen, such as glucosylceramide, mannosyldiinositol phosphorylceramide or a fungal protein target translates into high pathogen selectivity. However, a lower target concentration, absence or change in the specific fungal target can naturally lead to resistance, although such resistance in turn could result in reduced pathogen virulence. The question is then to be or not to be membrane active - what is the best choice for a successful AFP? In this review we deliberate on this question by focusing on the recent advances in our knowledge on how natural AFPs target fungi.

Pharmacokinetics of Posaconazole Suspension in Lung Transplant Patients with and without Cystic Fibrosis

Invasive fungal infections (IFIs) are common among lung transplant recipients (LTRs). Posaconazole is an important antifungal agent for both prophylaxis and treatment of IFIs; however, detailed pharmacokinetic data are limited among LTRs, particularly those with cystic fibrosis (CF). Our objective was to conduct a pharmacokinetic study of posaconazole oral suspension among LTRs, with particular attention to patients with CF. We enrolled 20 LTRs, 7 with CF and 13 with other underlying lung diseases. Average daily doses in CF and non-CF patients were 829 and 862 mg, respectively. After ≥5 days of treatment, only 4 patients had average plasma concentrations of >0.7 μg/ml. Average steady-state plasma concentrations were 61% lower in CF patients (0.233 μg/ml) than in non-CF LTRs (0.594 μg/ml; P = 0.03). The average dose-normalized plasma area-under-the-curve (AUC) values were also lower in CF (0.007 h·μg/ml) than in non-CF LTRs (0.02 h·μg/ml; P = 0.02). The weight-normalized apparent oral clearance values were 2.51 and 0.74 liters/h/kg among CF and non-CF LTRs, respectively (P = 0.005). Despite significant interpatient variability, plasma trough concentrations were strongly correlated with posaconazole AUC across all LTRs (r(2) = 0.95, P < 0.0001). Taken together, our study highlights a critical need to incorporate new formulations of posaconazole into prophylaxis and treatment strategies for LTRs, particularly those with CF. Future pharmacokinetic studies of both tablet and intravenous formulations must consider LTR-specific factors and incorporate a therapeutic drug monitoring plan in this patient population.

Notes from the Field: Probable Mucormycosis Among Adult Solid Organ Transplant Recipients at an Acute Care Hospital - Pennsylvania, 2014-2015

On September 17, 2015, the Pennsylvania Department of Health (PADOH) notified CDC of a cluster of three potentially health care-associated mucormycete infections that occurred among solid organ transplant recipients during a 12-month period at hospital A. On September 18, hospital B reported that it had identified an additional transplant recipient with mucormycosis. Hospitals A and B are part of the same health care system and are connected by a pedestrian bridge. PADOH requested CDC's assistance with an on-site investigation, which started on September 22, to identify possible sources of infection and prevent additional infections.

Pulmonary Fungal Diseases in Immunocompetent Hosts: A Single-Center Retrospective Analysis of 35 Subjects

BACKGROUND

Pulmonary fungal disease is an emerging issue in immunocompetent patients, for whom the characteristics are only partially understood.

METHODS

We conducted a single-center retrospective study of histologically verified pulmonary fungal disease in Eastern China from 2006 to 2014 to understand the demographics, clinical manifestations, therapeutic approaches, and factors associated with prognosis in this population. All cases were diagnosed according to the 2008 European Organization for the Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infection Diseases Mycoses Study Group definition criteria.

RESULTS

A total of 112 cases of pulmonary fungal diseases were enrolled (35 proven, 16 probable, 61 possible), and we analyzed the 35 patients with histologically proven pulmonary fungal diseases in this study. The main fungal species identified were Aspergillus (51.4 %), Cryptococcus (22.9 %), and Mucor (2.4 %). Treatment consisted of antifungal therapeutic agents (54.3 %), surgery and postsurgical agents (25.7 %), or surgery alone (14.3 %). The overall crude mortality rate was 14.3 %, and the mortality due to pulmonary fungal infections was 2.9 %. Significant predictors of mortality by univariate analysis were hypoalbuminemia (P = 0.005), cancer (P = 0.008), and positive culture (P = 0.044). Additionally, hypoalbuminemia was the only risk factor for mortality by multivariate analysis (RR = 7.56, 95 % CI 1.38-41.46).

CONCLUSION

Pulmonary fungal disease in immunocompetent patients, with Aspergillus as the most common identified species, had a prognosis that was influenced by the level of serum albumin.

Disseminated cryptococcal infection in allogeneic stem cell transplant patients: a rare cause of acute kidney injury

Hematopoietic stem cell transplantation (HSCT) can be lifesaving for some of the deadliest hematologic diseases. However, immunosuppression, polypharmacy and risk of infectious complications associated with HSCT can increase morbidity and mortality for recipients. Incidence of acute kidney injury (AKI) after HSCT can be as high as 70%, and concomitant infection can be a therapeutic challenge for oncologists, nephrologists and infectious disease specialists. We illustrate this challenge in the case of a 31-year-old man with acute lymphoblastic leukemia who underwent a double cord HSCT complicated by GvHD, systemic cryptococcal and BK virus infections and AKI. Kidney biopsy showed round to cup-shaped organisms with occasional budding, consistent with Cryptococcus and thrombotic microangiopathy. We discuss our findings and a literature review of disseminated cryptococcal infection with renal involvement after HSCT.

Filamentous Fungi

Filamentous mycoses are often associated with significant morbidity and mortality. Prompt diagnosis and aggressive treatment are essential for good clinical outcomes in immunocompromised patients. The host immune response plays an essential role in determining the course of exposure to potential fungal pathogens. Depending on the effectiveness of immune response and the burden of organism exposure, fungi can either be cleared or infection can occur and progress to a potentially fatal invasive disease. Nonspecific cellular immunity (i.e., neutrophils, natural killer [NK] cells, and macrophages) combined with T-cell responses are the main immunologic mechanisms of protection. The most common potential mold pathogens include certain hyaline hyphomycetes, endemic fungi, the Mucorales , and some dematiaceous fungi. Laboratory diagnostics aimed at detecting and differentiating these organisms are crucial to helping clinicians make informed decisions about treatment. The purpose of this chapter is to provide an overview of the medically important fungal pathogens, as well as to discuss the patient characteristics, antifungal-therapy considerations, and laboratory tests used in current clinical practice for the immunocompromised host.

[Invasive yeast diseases in solid organ transplant recipients]

Invasive yeast diseases are uncommon nowadays in solid organ transplant recipients. Invasive candidiasis (2%) usually presents during the first month after transplantation in patients with risk factors. Both common and transplant-specific risk factors have been identified, allowing very efficacious targeted prophylaxis strategies. The most common clinical presentations are fungaemia and local infections near the transplantation area. Cryptococcosis is usually a late infection. Its incidence remains stable and the specific risk factors have not been identified. When cryptococcosis is detected very early, transmission with the allograft should be considered. The most common clinical presentations include meningitis, pneumonia, and disseminated infection. Intracranial hypertension and immune reconstitution syndrome have to be considered. No therapeutic clinical trials have been conducted in solid organ transplant recipients, thus treatment recommendations are derived from data obtained from the general population. It is particularly important to consider the possibility of drug-drug interactions, mainly between azoles and calcineurin inhibitors. Both invasive candidiasis and cryptococcosis increase the mortality significantly in solid organ transplant recipients.

Favorable Evolution of Cryptococcal Meningitis in the Context of Flucytosine Resistance

Cryptococcal meningitis is a critical illness affecting 0.2% to 5% solid-organ transplant recipients with a 40% to 50% mortality. We report the case of a 48-year-old lung transplant recipient, who, 15 months after a right lung graft, kept parakeets and developed meningitis due to Cryptococcus neoformans. Immunosuppressive treatment was based on a quadruple sequential immunosuppressive therapy that included induction therapy with thymoglobulin, followed by corticosteroids, calcineurin inhibitors, and mycophenolate mofetil. Antifungal susceptibility testing of Cryptococcus neoformans showed resistance to flucytosine and intermediate sensitivity to fluconazole. Initial treatment adhered to international guidelines; however, the patient could not tolerate an effective double-antifungal therapy during the first 2 months of treatment. Despite this delayed treatment for an aggressive infection in an immunocompromised patient, the patient survived without relapse and received maintenance treatment with fluconazole during the course of 3 years. Administration of calcineurin inhibitors as immunosuppressive treatment may partly explain this outcome, as this therapeutic class is known to protect from severe forms of cryptococcal meningitis.

Virulence and Resistance to Antifungal Therapies of Scopulariopsis Species

Scopulariopsisis an emerging opportunistic fungus characterized by its high resistance to antifungal therapies. We have developed a murine model of disseminated infection in immunosuppressed animals by intravenous inoculation ofScopulariopsis brevicaulisandScopulariopsis brumptii, the most clinically relevant species, in order to evaluate their virulence and their responses to conventional antifungal treatments. Survival and tissue burden studies showed thatS. brumptiiwas more virulent thanS. brevicaulis The three drugs tested, liposomal amphotericin B, posaconazole, and voriconazole, prolonged the survival of mice infected withS. brumptii, but none showed efficacy againstS. brevicaulis The different therapies were only able to modestly reduce the fungal burden of infected tissue; however, in general, despite the high serum levels reached, they showed poor efficacy in the treatment of the infection. Unfortunately, the most effective therapy forScopulariopsisinfections remains unresolved.

Genotyping bacterial and fungal pathogens using sequence variation in the gene for the CCA-adding enzyme

BACKGROUND

To allow an immediate treatment of an infection with suitable antibiotics and bactericides or fungicides, there is an urgent need for fast and precise identification of the causative human pathogens. Methods based on DNA sequence comparison like 16S rRNA analysis have become standard tools for pathogen verification. However, the distinction of closely related organisms remains a challenging task. To overcome such limitations, we identified a new genomic target sequence located in the single copy gene for tRNA nucleotidyltransferase fulfilling the requirements for a ubiquitous, yet highly specific DNA marker. In the present study, we demonstrate that this sequence marker has a higher discriminating potential than commonly used genotyping markers in pro- as well as eukaryotes, underscoring its applicability as an excellent diagnostic tool in infectology.

RESULTS

Based on phylogenetic analyses, a region within the gene for tRNA nucleotidyltransferase (CCA-adding enzyme) was identified as highly heterogeneous. As prominent examples for pro- and eukaryotic pathogens, several Vibrio and Aspergillus species were used for genotyping and identification in a multiplex PCR approach followed by gel electrophoresis and fluorescence-based product detection. Compared to rRNA analysis, the selected gene region of the tRNA nucleotidyltransferase revealed a seven to 30-fold higher distinction potential between closely related Vibrio or Aspergillus species, respectively. The obtained data exhibit a superb genome specificity in the diagnostic analysis. Even in the presence of a 1,000-fold excess of human genomic DNA, no unspecific amplicons were produced.

CONCLUSIONS

These results indicate that a relatively short segment of the coding region for tRNA nucleotidyltransferase has a higher discriminatory potential than most established diagnostic DNA markers. Besides identifying microbial pathogens in infections, further possible applications of this new marker are food hygiene controls or metagenome analyses.

An alternative host model of a mixed fungal infection by azole susceptible and resistant Aspergillus spp strains

Aspergillus fumigatus is the most common mold involved in human infections. However, the number of non-fumigatus species able to cause disease is continuously increasing. Among them, Aspergillus lentulus is reported in hematological and cystic fibrosis patients and in those treated with corticosteroids. A. lentulus differs from A. fumigatus in some clinically relevant aspects such as virulence and antifungal susceptibility, showing high MICs to most antifungals. Previous studies proved that A. lentulus was pathogenic in immunocompromised mice, although the course of the infection was delayed compared to A. fumigatus. These differences could explain why A. lentulus is mostly found in mixed infections with A. fumigatus challenging the diagnosis and treatment. We used the alternative model host Galleria mellonella to compare virulence, host interaction, fungal burden and antifungal response when larvae were infected with A. fumigatus or A. lentulus alone, and with a mixture of both species. A. lentulus was pathogenic in G. mellonella but infected larvae did not respond to therapeutic doses of voriconazole. We were able to simultaneously detect A. fumigatus and A. lentulus by a multiplex Nested Real Time PCR (MN-PCR). Comparative analysis of larvae histological sections showed melanization of both species but presented a different pattern of immune response by haemocytes. Analysis of fungal burden and histology showed that A. lentulus survived in the G. mellonella despite the antifungal treatment in single and mixed infections. We conclude that the simultaneous presence of antifungal susceptible and resistant Aspergillus species would likely complicate the management of these infections.

Cytomegalovirus disease is associated with higher all-cause mortality after lung transplantation despite extended antiviral prophylaxis

BACKGROUND

The duration of anticytomegalovirus (CMV) prophylaxis after lung transplantation (LT) varies among transplant centers.

METHODS

A retrospective review of CMV donor-seropositive/recipient-seronegative (D+/R-) and CMV recipient-seropositive (R+) LT patients between January 2005 and September 2012 was performed. Starting January 2007, valganciclovir prophylaxis was given for at least 12 months (often lifelong) for CMV D+/R- and extended from three to six months for R+ LT patients. Risks of CMV infection and CMV disease, and mortality after LT, were assessed.

RESULTS

A total of 88 LT patients were studied, including 32 CMV D+/R-, and 56 R+ patients. During the follow-up period, 11 (12.5%) patients had asymptomatic CMV infection, and nine (10.3%) developed CMV disease. CMV disease (HR, 4.189; 95% CI: 1.672-10.495; p = 0.002) and CMV infection and disease (HR, 3.775; 95% CI: 1.729-8.240; p = 0.001) were significant risk factors for mortality. Overall, no significant difference was observed in rates of CMV infection or disease among LT recipients who received shorter vs. extended CMV prophylaxis.

CONCLUSIONS

Despite extended prophylaxis, LT patients remain at risk of CMV infection and disease. CMV remains associated with increased mortality after transplantation.

Invasive candidiasis in liver transplant patients: Incidence and risk factors in a pediatric cohort

Prolonged OR, re-transplantation, and high-volume intraoperative transfusion have been associated with increased risk for IC in adult LT recipients. Antifungal prophylaxis is recommended for adult patients with these risk factors. There are limited data on the incidence of and risk factors for IC in pediatric LT recipients. A retrospective cohort study of all pediatric LT patients at the CHOP between 2000 and 2012 and the CHP between 2004 and 2012 was performed to define the incidence of IC within 30 days of LT. A 3:1 matched case-control study with incidence density sampling was performed. Conditional logistic regression analyses were used to explore risk factors associated with IC. Among 397 recipients, the incidence of IC was 2.5%. Bivariate analyses showed that ICU admission prior to transplant, OR > 10 h, intraoperative volume infusion of >300 mL/kg, and broad-spectrum antibiotics were significantly associated with IC. In a multivariate model, only ICU admission remained significantly associated with IC. Antifungal prophylaxis was not significantly protective against IC. The low incidence of IC and lack of an identified protective effect from antifungal prophylaxis suggest that prophylaxis in pediatric LT recipients should not be routinely recommended to prevent IC events in the first 30 days post-transplant.

Innate host defenses against Cryptococcus neoformans

Cryptococcus neoformans, the predominant etiological agent of cryptococcosis, can cause life-threatening infections of the central nervous system in immunocompromised and immunocompetent individuals. Cryptococcal meningoencephalitis is the most common disseminated fungal infection in AIDS patients, and remains the third most common invasive fungal infection among organ transplant recipients. The administration of highly active antiretroviral therapy (HAART) has resulted in a decrease in the number of cases of AIDS-related cryptococcosis in developed countries, but in developing countries where HAART is not readily available, Cryptococcus is still a major concern. Therefore, there is an urgent need for the development of novel therapies and/or vaccines to combat cryptococcosis. Understanding the protective immune responses against Cryptococcus is critical for development of vaccines and immunotherapies to combat cryptococcosis. Consequently, this review focuses on our current knowledge of protective immune responses to C. neoformans, with an emphasis on innate immune responses.

Mucorales-Specific T Cells in Patients with Hematologic Malignancies

Background

Invasive mucormycosis (IM) is an emerging life-threatening fungal infection. It is difficult to obtain a definite diagnosis and to initiate timely intervention. Mucorales-specific T cells occur during the course of IM and are involved in the clearance of the infection. We have evaluated the feasibility of detecting Mucorales-specific T cells in hematological patients at risk for IM, and have correlated the detection of such cells with the clinical conditions of the patients.

Methods and Findings

By using an enzyme linked immunospot assay, the presence of Mucorales-specific T cells in peripheral blood (PB) samples has been investigated at three time points during high-dose chemotherapy for hematologic malignancies. Mucorales-specific T cells producing interferon-γ, interleukin-10 and interleukin-4 were analysed in order to detect a correlation between the immune response and the clinical picture. Twenty-one (10.3%) of 204 patients, accounting for 32 (5.3%) of 598 PB samples, tested positive for Mucorales-specific T cells. Two groups could be identified. Group 1, including 15 patients without signs or symptoms of invasive fungal diseases (IFD), showed a predominance of Mucorales-specific T cells producing interferon-gamma. Group 2 included 6 patients with a clinical picture consistent with invasive fungal disease (IFD): 2 cases of proven IM and 4 cases of possible IFD. The proven patients had significantly higher number of Mucorales-specific T cells producing interleukin-10 and interleukin-4 and higher rates of positive samples by using derived diagnostic cut-offs when compared with the 15 patients without IFD.

Conclusions

Mucorales-specific T cells can be detected and monitored in patients with hematologic malignancies at risk for IM. Mucorales-specific T cells polarized to the production of T helper type 2 cytokines are associated with proven IM and may be evaluated as a surrogate diagnostic marker for IM.