Activities of caspofungin, itraconazole, posaconazole, ravuconazole, voriconazole, and amphotericin B against 448 recent clinical isolates of filamentous fungi

We examined the in vitro activity of caspofungin, posaconazole, voriconazole, ravuconazole, itraconazole, and amphotericin B against 448 recent clinical mold isolates. The endpoint for reading caspofungin was the minimum effective concentration (MEC). Among the triazoles, posaconazole was most active, inhibiting 95% of isolates at <or=1 microg/ml, followed by ravuconazole (91%), voriconazole (90%), and itraconazole (79%). Caspofungin and amphotericin B inhibited 93% and 89% of isolates at <or=1 microg/ml, respectively, with caspofungin demonstrating an MEC 90 of 0.12 microg/ml. All three new triazoles and caspofungin inhibited >95% of Aspergillus spp. at <or=1 microg/ml compared to 83% for itraconazole and 91% for amphotericin B. Amphotericin B inhibited only 38% of Aspergillus terreus isolates at <or=1 microg/ml, whereas the three new triazoles and caspofungin inhibited all A. terreus at <or=0.5 microg/ml. The new triazoles and caspofungin have excellent in vitro activity against a very large collection of recent clinical isolates of Aspergillus spp., and some in vitro activity against selected other filamentous fungi.

Pseudophakic endophthalmitis. Diagnosis and management

Eighty-three cases of endophthalmitis occurring in eyes with intraocular lenses are presented. A problem with the cataract section was felt to contribute to development of the endophthalmitis in 22% of patients. Seventy-five percent of eyes were culture positive with a microbiologic spectrum similar to other reported series without lens implants. Staphylococcus epidermidis was the most common organism accounting for 38% of the isolates. Therapeutic vitrectomy was performed in 46 cases (55%), generally in those eyes with the most severe inflammation. Intraocular lenses were removed in 23 cases (28%), usually to facilitate vitrectomy. Only 1 of 57 eyes with bacterial endophthalmitis could not be sterilized while the intraocular lens was retained. Visual acuity of 20/400 or better was achieved in 63% of culture positive cases, in 78% of eyes infected with S. epidermidis, and in 94% of culture negative eyes.

Cell death control: the interplay of apoptosis and autophagy in the pathogenicity of Sclerotinia sclerotiorum

Programmed cell death is characterized by a cascade of tightly controlled events that culminate in the orchestrated death of the cell. In multicellular organisms autophagy and apoptosis are recognized as two principal means by which these genetically determined cell deaths occur. During plant-microbe interactions cell death programs can mediate both resistant and susceptible events. Via oxalic acid (OA), the necrotrophic phytopathogen Sclerotinia sclerotiorum hijacks host pathways and induces cell death in host plant tissue resulting in hallmark apoptotic features in a time and dose dependent manner. OA-deficient mutants are non-pathogenic and trigger a restricted cell death phenotype in the host that unexpectedly exhibits markers associated with the plant hypersensitive response including callose deposition and a pronounced oxidative burst, suggesting the plant can recognize and in this case respond, defensively. The details of this plant directed restrictive cell death associated with OA deficient mutants is the focus of this work. Using a combination of electron and fluorescence microscopy, chemical effectors and reverse genetics, we show that this restricted cell death is autophagic. Inhibition of autophagy rescued the non-pathogenic mutant phenotype. These findings indicate that autophagy is a defense response in this necrotrophic fungus/plant interaction and suggest a novel function associated with OA; namely, the suppression of autophagy. These data suggest that not all cell deaths are equivalent, and though programmed cell death occurs in both situations, the outcome is predicated on who is in control of the cell death machinery. Based on our data, we suggest that it is not cell death per se that dictates the outcome of certain plant-microbe interactions, but the manner by which cell death occurs that is crucial.

During plant-microbe interactions, regulated cell death known as programmed cell death (PCD) can mediate both resistant and susceptible interactions. Sclerotinia sclerotiorum induces an apoptotic spreading cell death during infection, via the secreted virulence determinant oxalic acid. Oxalic acid deficient fungal mutants are non-pathogenic, and trigger a restricted cell death phenotype in the host that unexpectedly exhibits markers associated with the plant hypersensitive response. Using electron and fluorescence microscopy, chemical effectors and reverse genetics, we show that this restricted cell death is autophagic. Inhibition of autophagy rescued the non-pathogenic mutant phenotype. These findings indicate that autophagy is a defense response in this interaction and suggest a novel function associated with oxalic acid: the suppression of autophagy. Thus, the control of cell death, dictated by the plant (autophagy) or the fungus (apoptosis), can lead to opposing outcomes. We propose that the type of cell death is decisive to the outcome of certain plant-microbe interactions.

Efflux in fungi: la pièce de résistance

Pathogens must be able to overcome both host defenses and antimicrobial treatment in order to successfully infect and maintain colonization of the host. One way fungi accomplish this feat and overcome intercellular toxin accumulation is efflux pumps, in particular ATP-binding cassette transporters and transporters of the major facilitator superfamily. Members of these two superfamilies remove many toxic compounds by coupling transport with ATP hydrolysis or a proton gradient, respectively. Fungal genomes encode a plethora of members of these families of transporters compared to other organisms. In this review we discuss the role these two fungal superfamilies of transporters play in virulence and resistance to antifungal agents. These efflux transporters are responsible not only for export of compounds involved in pathogenesis such as secondary metabolites, but also export of host-derived antimicrobial compounds. In addition, we examine the current knowledge of these transporters in resistance of pathogens to clinically relevant antifungal agents.

Rapid global expansion of the fungal disease chytridiomycosis into declining and healthy amphibian populations

The fungal disease chytridiomycosis, caused by Batrachochytrium dendrobatidis, is enigmatic because it occurs globally in both declining and apparently healthy (non-declining) amphibian populations. This distribution has fueled debate concerning whether, in sites where it has recently been found, the pathogen was introduced or is endemic. In this study, we addressed the molecular population genetics of a global collection of fungal strains from both declining and healthy amphibian populations using DNA sequence variation from 17 nuclear loci and a large fragment from the mitochondrial genome. We found a low rate of DNA polymorphism, with only two sequence alleles detected at each locus, but a high diversity of diploid genotypes. Half of the loci displayed an excess of heterozygous genotypes, consistent with a primarily clonal mode of reproduction. Despite the absence of obvious sex, genotypic diversity was high (44 unique genotypes out of 59 strains). We provide evidence that the observed genotypic variation can be generated by loss of heterozygosity through mitotic recombination. One strain isolated from a bullfrog possessed as much allelic diversity as the entire global sample, suggesting the current epidemic can be traced back to the outbreak of a single clonal lineage. These data are consistent with the current chytridiomycosis epidemic resulting from a novel pathogen undergoing a rapid and recent range expansion. The widespread occurrence of the same lineage in both healthy and declining populations suggests that the outcome of the disease is contingent on environmental factors and host resistance.

Host and pathogen ecology drive the seasonal dynamics of a fungal disease, white-nose syndrome

Seasonal patterns in pathogen transmission can influence the impact of disease on populations and the speed of spatial spread. Increases in host contact rates or births drive seasonal epidemics in some systems, but other factors may occasionally override these influences. White-nose syndrome, caused by the emerging fungal pathogen Pseudogymnoascus destructans, is spreading across North America and threatens several bat species with extinction. We examined patterns and drivers of seasonal transmission of P. destructans by measuring infection prevalence and pathogen loads in six bat species at 30 sites across the eastern United States. Bats became transiently infected in autumn, and transmission spiked in early winter when bats began hibernating. Nearly all bats in six species became infected by late winter when infection intensity peaked. In summer, despite high contact rates and a birth pulse, most bats cleared infections and prevalence dropped to zero. These data suggest the dominant driver of seasonal transmission dynamics was a change in host physiology, specifically hibernation. Our study is the first, to the best of our knowledge, to describe the seasonality of transmission in this emerging wildlife disease. The timing of infection and fungal growth resulted in maximal population impacts, but only moderate rates of spatial spread.

Neurologic complications of endocarditis: a 12-year experience

We reviewed the neurologic complications in 113 patients with native and 62 patients with prosthetic valve endocarditis. Neurologic complications occurred with the same frequency (35.3% vs 38.7%) and distribution among the two groups. Death occurred in 20.6% of patients with neurologic complications and in 13.6% of patients without neurologic complications (p = 0.23). Staphylococcus aureus endocarditis correlated statistically with the development of neurologic complications (p less than 0.01) and death (p less than 0.01). Among 50 patients discharged from the hospital after receiving only medical treatment for native valve endocarditis, and followed for a mean period of 48 months, there was one patient with mitral valve prolapse and stroke. We conclude that (1) neurologic complications occur with the same frequency in native and prosthetic valve endocarditis, (2) S aureus endocarditis increases the risk of neurologic complications and death, (3) mortality is not significantly increased in patients with neurologic complications, and (4) an episode of treated native valve endocarditis does not increase the natural history of stroke in valvular disease.

Candidemia and Invasive Candidiasis

Invasive candidiasis (IC) is a collective term that refers to a group of infectious syndromes caused by a variety of species of Candida, 6 of which cause most cases globally. Candidemia is probably the most commonly recognized syndrome associated with IC; however, Candida can cause invasive infection of any organ, especially visceral organs, vasculature, bones and joints, the eyes and central nervous system. Targeted prevention and empirical therapy are important interventions for patients at high risk for IC, and the current approach should be based on a combination of clinical risk factors and non-culture-based diagnostics, when available.

Definitions of fungal rhinosinusitis

Classification of fungal rhinosinusitis is important for the accurate prediction of prognosis and direct therapy. The most important distinction is between invasive and noninvasive fungal rhinosinusitis. Within the invasive division are acute invasive and chronic invasive (granulomatous and nongranulomatous forms) rhinosinusitis. Within the noninvasive division are saprophytic colonization, fungus balls, and allergic fungal rhinosinusitis. This article briefly outlines the definition and management of each of these manifestations.

An Arabidopsis thaliana thionin gene is inducible via a signal transduction pathway different from that for pathogenesis-related proteins

Two cDNAs encoding thionin preproteins have been isolated from Arabidopsis thaliana. The corresponding genes have been designated Thi2.1 and Thi2.2. Southern blot analysis suggests that A. thaliana most probably contains single genes for both thionins. Thi2.2 transcripts have a low basal level in seedlings and show circadian variation. Thi2.2 transcripts were also detected in rosette leaves. No potent elicitors have been found for the Thi2.2 gene. Transcripts of the Thi2.1 gene are not detectable in seedlings but are present in rosette leaves and at a very high level in flowers and in siliques. The expression of the Thi2.1 gene is highly inducible in seedlings by pathogens, silver nitrate, and methyl jasmonate, but not by salicylate, indicating that the gene is induced by a signal transduction pathway that is at least partly different from that for the pathogenesis-related proteins.

Infectious causes of acute pancreatitis

A wide variety of infectious agents has been associated with acute pancreatitis. Strict diagnostic criteria were developed to assess with relationship between individual microorganisms and acute pancreatitis. Pathologic or radiologic evidence of pancreatitis associated with well-documented infection was noted with viruses (mumps, coxsackie, hepatitis B, cytomegalovirus, varicella-zoster virus, herpes simplex virus), bacteria (Mycoplasma, Legionella, Leptospira, Salmonella), fungi (Aspergillus), and parasites (Toxoplasma, Cryptosporidium, Ascaris). Clues to the infectious nature of pancreatitis lay in the characteristic signs and symptoms associated with the particular infectious agent. How often these agents are responsible for idiopathic pancreatitis is unclear.

Exogenous fungal endophthalmitis

The authors report 19 cases of exogenous fungal endophthalmitis managed between 1969 and 1986. These developed after ocular surgery (5 cases), after trauma (6 cases), by intraocular spread from fungal keratitis (4 cases), after therapeutic keratoplasty for keratitis (3 cases), and by spontaneous infection of a filtration bleb (1 case). The diagnosis of endophthalmitis was made from 3 days to 4 months after surgery or trauma. In patients with preexisting keratitis, endophthalmitis was noted 2 weeks to 5 months after the onset of keratitis. Seventeen cases were caused by filamentous fungi; two were caused by yeast. Fusarium (6 cases) and Acremonium (3 cases) accounted for approximately one half of the isolates. Forty-two percent of the patients recovered 20/400 or better acuity (3 of 5 postoperative cases, 4 of 6 trauma cases, and 1 of 4 keratitis cases). The clinical and microbiologic features of these cases are presented, and recommendations for management are offered.

Esophageal infections in immunosuppressed patients after marrow transplantation

We reviewed all cases of infectious esophagitis diagnosed after marrow transplantation during a 2-yr period. Twenty-one infections were found during 46 fiberoptic endoscopic examinations; most infections were viral, with equal numbers due to cytomegalovirus and herpes simplex virus. These infections presented with nonspecific esophageal symptoms weeks to months after transplantation. Diagnoses depended on histology and viral cultures. During the same time span, autopsies revealed 25 cases of infective esophagitis among 59 patients; most were again viral, with equal numbers of herpes simplex virus and cytomegalovirus infections. Mixed infections due to viral, fungal, and bacterial pathogens were found in both endoscopy and autopsy series. The prevalence of esophageal infection in marrow transplant patients with esophageal symptoms is high, but the organisms could not be predicted on the basis of symptoms, oropharyngeal surveillance cultures, or esophageal x-ray. Accurate diagnosis requires that endoscopic biopsy specimens and brushings be examined by both histologic and virologic methods.

Fungus balls of the paranasal sinuses

Fungus balls of the paranasal sinuses represent a noninvasive manifestation of fungal sinusitis. Patients are immunocompetent but no more allergic than the general population. There is little tissue reaction to the tangled mat of hyphae. If the patient becomes immunocompromised, then the fungus ball may become invasive, as illustrated by an included case report. One hundred sixty-three additional cases of patients with paranasal sinus fungus balls are reviewed from the literature.

Geographic variation in allergic fungal rhinosinusitis

Allergic fungal rhinosinusitis (AFRS) has a worldwide distribution. This survey of 20 otolaryngologic practices throughout the United States confirmed a variation in the frequency of AFRS relative to endoscopic sinus procedures performed for all other diagnoses. The highest incidence occurred in Memphis, Tennessee at 23%, with three other southern practices reporting a frequency of at least 10%. In the northern locations the frequency ranged from 0 to 4%. No correlation with mould counts was demonstrated, possibly because of incomplete mould data relative to most of the surgical locations.

Spinal infections

Spinal infections can be thought of as a spectrum of disease comprising spondylitis, discitis, spondylodiscitis, pyogenic facet arthropathy, epidural infections, meningitis, polyradiculopathy and myelitis. Radiological evaluations have gained importance in the diagnosis, treatment planning, treatment and treatment monitoring of the spinal infections. Conventional radiographs are usually the initial imaging study. The sensitivity and specificity of the plain radiographs are very low. The sensitivity of CT is higher while it lacks of specificity. Conventional CT has played minor role for the diagnosis of early spondylitis and disc space infection and for follow-up, researches are going on the value of MDCT. MRI is as sensitive, specific and accurate as combined nuclear medicine studies and the method of choice for the spondylitis. Low signal areas of the vertebral body, loss of definition of the end plates and interruption of the cortical continuity, destruction of the cortical margins are typical on T1WI whereas high signal of affected areas of the vertebral body and disc is typical on T2WI. Contrast is mandatory and increases conspicuity, specificity, and observer confidence in the diagnosis and facilitates the treatment planning. Contrast enhancement is the earliest sign and pathognomonic in the acute inflammatory episode and even in the subtle infection then persists to a varying degree for several weeks or months. The outcome of the treatment is influenced by the type of infection and by the degree of neurologic compromise before treatment. There is an increasing move away from surgical intervention towards conservative therapy, percutaneous drainage of abscess or both. It is therefore critical to monitor treatment response, particularly in the immuno-deficient population.

Extended criteria for organ acceptance. Strategies for achieving organ safety and for increasing organ pool

The terms extended donor or expanded donor mean changes in donor acceptability criteria. In almost all cases, the negative connotations of these terms cannot be justified. Factors considered to affect donor or organ acceptability have changed with time, after showing that they did not negatively affect graft or patient survival per se or when the adequate measures had been adopted. There is no age limit to be an organ donor. Kidney and liver transplantation from donors older than 65 years can have excellent graft and patient actuarial survival and graft function. Using these donors can be from an epidemiological point of view the most important factor to esablish the final number of cadaveric liver and kidney transplantations. Organs with broad structural parenchyma lesion with preserved functional reserve and organs with reversible functional impairment can be safely transplanted. Bacterial and fungal donor infection with the adequate antibiotic treatment of donor and/or recipient prevents infection in the latter. The organs, including the liver, from donors with infection by the hepatitis B and C viruses can be safely transplanted to recipients with infection by the same viruses, respectively. Poisoned donors and non-heart-beating donors, grafts from transplant recipients, reuse of grafts, domino transplant and splitting of one liver for two recipients can be an important and safe source of organs for transplantation.

Microbiology of Cystic Fibrosis Airway Disease

Although survival of individuals with cystic fibrosis (CF) has been continuously improving for the past 40 years, respiratory failure secondary to recurrent pulmonary infections remains the leading cause of mortality in this patient population. Certain pathogens such as Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and species of the Burkholderia cepacia complex continue to be associated with poorer clinical outcomes including accelerated lung function decline and increased mortality. In addition, other organisms such as anaerobes, viruses, and fungi are increasingly recognized as potential contributors to disease progression. Culture-independent molecular methods are also being used for diagnostic purposes and to examine the interaction of microorganisms in the CF airway. Given the importance of CF airway infections, ongoing initiatives to promote understanding of the epidemiology, clinical course, and treatment options for these infections are needed.