Use of a repetitive DNA probe to type clinical and environmental isolates of Aspergillus flavus from a cluster of cutaneous infections in a neonatal intensive care unit

A single-source nosocomial outbreak of Aspergillus flavus uncovered by genotyping

During construction work (2017-2019), an increase in Aspergillus flavus infections was noted among pediatric patients, the majority of whom were receiving amphotericin B prophylaxis. Microsatellite genotyping was used to characterize the outbreak. A total of 153 A. flavus isolates of clinical and environmental origin were included. Clinical isolates included 140 from 119 patients. Eight patients were outbreak-related patients, whereas 111 were outbreak-unrelated patients from Danish hospitals (1994-2023). We further included four control strains. Nine A. flavus isolates were from subsequent air sampling in the outbreak ward (2022-2023). Typing followed Rudramurthy et al.(S. M. Rudramurthy, H. A. de Valk, A. Chakrabarti, J. Meis, and C. H. W. Klaassen, PLoS One 6:e16086, 2011, https://doi.org/10.1371/journal.pone.0016086). Minimum spanning tree (MST) and discriminant analysis of principal components (DAPC) were used for cluster analysis. DAPC analysis placed all 153 isolates in five clusters. Microsatellite marker pattern was clearly distinct for one cluster compared to the others. The same cluster was observed in an MST. This cluster included all outbreak isolates, air-sample isolates, and additional patient isolates from the outbreak hospital, previously undisclosed as outbreak related. The highest air prevalence of A. flavus was found in two technical risers of the outbreak ward, which were then sealed. Follow-up air samples were negative for A. flavus. Microsatellite typing defined the outbreak as nosocomial and facilitated the identification of an in-hospital source. Six months of follow-up air sampling was without A. flavus. Outbreak-related/non-related isolates were easily distinguished with DAPC and MST, as the outbreak clone's distinct marker pattern was delineated in both statistical analyses. Thus, it could be a variant of A. flavus, with a niche ability to thrive in the outbreak-hospital environment.

IMPORTANCE

Aspergillus flavus can cause severe infections and hospital outbreaks in immunocompromised individuals. Although lack of isogeneity does not preclude an outbreak, our study underlines the value of microsatellite genotyping in the setting of potential A. flavus outbreaks. Microsatellite genotyping documented an isogenic hospital outbreak with an internal source. This provided the "smoking gun" that prompted the rapid allocation of resources for thorough environmental sampling, the results of which guided immediate and relevant cleaning and source control measures. Consequently, we advise that vulnerable patients should be protected from exposure and that genotyping be included early in potential A. flavus outbreak investigations. Inspection and sampling are recommended at any site where airborne spores might disperse from. This includes rarely accessed areas where air communication to the hospital ward cannot be disregarded.

Role of mitochondrial farnesyltransferase gene in the prevention of the food spoilage fungi Aspergillus flavus by the antimicrobial natural preservative perillaldehyde

Aspergillus flavus, one of the most widely distributed and abundant genus of Aspergillus worldwide, poses an evident threat as a source of food contamination in grains and cereals. Perillaldehyde (PAE), a volatile essential oil extracted from the stem and leaves of Perilla frutescens L., exhibits potent antifungal activity. In our study, we investigated the role of Cox10, a key enzyme in the heme A synthesis pathway crucial for maintaining mitochondrial function. We found that cox10 is a sensitive gene of A. flavus in response to PAE by gene expression assay and GFP fluorescent localization tagging, and then we found that the deletion of this gene affects the growth and development of A. flavus, but the drug resistance is elevated. Through transcriptome sequencing and its experimental validation, the molecular mechanisms of stress triggered by the deletion of cox10 were further clarified, such as the decrease in intracellular drug content due to the increase in the expression of drug efflux proteins, and the increase in the thickness of cell wall due to the increase in the content of cell wall chitin. Clearly, cox10 plays a critical role in regulating various cellular processes of A. flavus, including growth, reproduction, development, as well as pathogenicity and drug resistance. These significant findings establish a solid theoretical foundation for the development of environmentally friendly, safe, and effective antifungal agents to combat A. flavus contamination.

Nosocomial transmission of Aspergillus flavus in a neonatal intensive care unit: Long-term persistence in environment and interest of MALDI-ToF mass-spectrometry coupled with convolutional neural network for rapid clone recognition

Aspergillosis of the newborn remains a rare but severe disease. We report four cases of primary cutaneous Aspergillus flavus infections in premature newborns linked to incubators contamination by putative clonal strains. Our objective was to evaluate the ability of matrix-assisted laser desorption/ionisation time of flight (MALDI-TOF) coupled to convolutional neural network (CNN) for clone recognition in a context where only a very small number of strains are available for machine learning. Clinical and environmental A. flavus isolates (n = 64) were studied, 15 were epidemiologically related to the four cases. All strains were typed using microsatellite length polymorphism. We found a common genotype for 9/15 related strains. The isolates of this common genotype were selected to obtain a training dataset (6 clonal isolates/25 non-clonal) and a test dataset (3 clonal isolates/31 non-clonal), and spectra were analysed with a simple CNN model. On the test dataset using CNN model, all 31 non-clonal isolates were correctly classified, 2/3 clonal isolates were unambiguously correctly classified, whereas the third strain was undetermined (i.e., the CNN model was unable to discriminate between GT8 and non-GT8). Clonal strains of A. flavus have persisted in the neonatal intensive care unit for several years. Indeed, two strains of A. flavus isolated from incubators in September 2007 are identical to the strain responsible for the second case that occurred 3 years later. MALDI-TOF is a promising tool for detecting clonal isolates of A. flavus using CNN even with a limited training set for limited cost and handling time.

Stem Cell Treatment for Diabetic Foot Ulcers: A Meta-analysis of Randomized Clinical Trials

GENERAL PURPOSE

To provide information on the efficacy of stem cells in the treatment of diabetic foot ulcers.

TARGET AUDIENCE

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES

After participating in this educational activity, the participant will: 1. Explain outcomes from the use of stem cell treatment for diabetic foot ulcers. 2. Identify features in the methodology of randomized controlled trials examining the efficacy of stem cells in the treatment of diabetic foot ulcers.

Mycoviruses in Fungi: Carcinogenesis of Fungal Agents May Not Always Be Mycotoxin Related

Certain viruses have been found to induce diverse biological pathways to carcinogenesis, evidenced by the presence of viral gene products in some tumors. Despite the fact that many fungal agents contain mycoviruses, until recently, their possible direct effects on human health, including carcinogenesis and leukemogenesis, had not been explored. In this regard, most studies of fungal agents have rightly concentrated on their mycotoxin formation and effects. Recently, the direct role of yeasts and fungi in the etiology of cancers, including leukemia, have been investigated. While greater attention has been placed on the carcinogenic effects of Candida, the role of filamentous fungi in carcinogenesis has also been explored. Recent findings from studies using the enzyme-linked immunosorbent assay (ELISA) technique indicate that the plasma of patients with acute lymphoblastic leukemia (ALL) uniformly contains antibodies for a certain mycovirus-containing Aspergillus flavus, while controls are negative. The exposure of mononuclear leukocytes from patients with ALL in full remission, and long-term survivors, to the product of this organism was reported to result in the re-development of typical genetics and cell surface phenotypes characteristic of active ALL. Mycoviruses are known to be able to significantly alter the biological characteristics and functions of their host. The possible carcinogenic and leukemogenic role of mycoviruses, with and without their host, needs to be further investigated.

Molds and More: Rare Fungal Infections in Preterm Infants <24 Weeks of Gestation

BACKGROUND

Extreme immature infants are at an increased risk of fungal infection due to immaturity of the skin barrier and the immune system. Besides Candida infections, in particular, Aspergillus may cause life-threatening diseases in preterm infants. Frequently, Aspergillus primarily affects the skin and may cause extensive damage.

METHODS

We searched our hospital database for fungal infections other than Candida in preterm infants treated between 2015 and 2020 at our level III neonatal intensive care unit of the University Hospital of Cologne.

RESULTS

In total, 13 preterm infants were identified. Of these, 11 had cutaneous Aspergillosis, one infant had severe enterocolitis caused by Aspergillus and Rhizopus and one had invasive intraabdominal Trichosporon mucoides infection. All infants were born <24 weeks of gestation, were delivered due to premature labor or chorioamnionitis, and had received prenatal steroids and/or hydrocortisone. Voriconazole and liposomal Amphotericin B were first-line treatments and the length of treatment varied between 3 and 148 days. Two infants died associated with severe infection. Liver toxicity was observed in six infants treated with Voriconazole. Therapeutic drug management for Voriconazole was performed in four infants. Target levels were not achieved by the doses that are recommended.

CONCLUSIONS

Rare fungal infections, predominantly cutaneous Aspergillosis affects the most immature preterm infants and may cause severe disease. Treatment with Voriconazole has a high rate of liver toxicity and target levels are difficult to achieve in extremely immature infants.

Infection prevention practices and the use of medical tapes

BACKGROUND

Medical tapes are ubiquitous in healthcare and there are currently no guidelines for their storage and use. Tapes cannot be cleaned or disinfected; yet, several clinicians may use a given roll for any number of patients. Reports of tape contamination associated with clinical infection have been published.

PURPOSE

We reviewed the literature reporting microbiological studies, case reports of infections, and nosocomial outbreaks associated with the use of medical tapes and other adhesive devices to assess the prevalence of this problem.

METHODS

We conducted a literature search for cross-contamination due to medical tape use in 6 databases in June 2020 using indexing terms for surgical tape, adhesive agent, adhesives or the keyword for tape. We compiled available evidence on tape contamination as a cause for healthcare-associated infections (HAIs).

MAIN FINDINGS

Forty-two publications reported relevant microbiological studies, case reports of infections, and/or nosocomial outbreaks. Results demonstrated that tape rolls handled with questionable practices can harbor pathogens. Some studies showed the association between contaminated tape and HAIs, which in some cases even led to death.

CONCLUSIONS

The time has come to establish national guidelines to help reduce the risk of cross-contamination from medical tapes. We offer suggested elements for these guidelines. The COVID-19 pandemic brings greater scrutiny to eliminate any avoidable cause of infection transmission.

Azole-Resistant Aspergillus fumigatus Harboring the TR34/L98H Mutation: First Report in Portugal in Environmental Samples

Introduction: The frequency in detection of azole-resistant Aspergillus fumigatus isolates has increased since 2010. In Portugal, the section Fumigati is one of the most frequent, and resistant strains to have been found in clinical and environmental contexts. Although several cryptic species within the Fumigati section show intrinsic resistance to azoles, one factor driving (acquired) resistance is selective pressure deriving from the extensive use of azoles. This is particularly problematic in occupational environments where high fungal loads are expected, and where there is an increased risk of human exposure and infection, with impact on treatment success and disease outcome. The mechanisms of resistance are diverse, but mainly associated with mutations in the cyp51A gene. Despite TR₃₄/L98H being the most frequent mutation described, it has only been detected in clinical specimens in Portugal. Methods: We analyzed 99 A. fumigatus isolates from indoor environments (healthcare facilities, spas, one dairy and one waste sorting unit) collected from January 2018 to February 2019 in different regions of Portugal. Isolates were screened for resistance to itraconazole, voriconazole and posaconazole by culture, and resistance was confirmed by broth microdilution. Sequencing of the cyp51A gene and its promoter was performed to detect mutations associated with resistance. Results: Overall, 8.1% of isolates were able to grow in the presence of at least one azole, and 3% (isolated from the air in a dairy and from filtering respiratory protective devices in a waste sorting industry) were pan-azole-resistant, bearing the TR₃₄/L98H mutation. Conclusion: For the first time in Portugal, we report environmental isolates bearing the TR₃₄/L98H mutation, isolated from occupational environments. Environmental surveillance of the emergence of azole-resistant A. fumigatus sensu stricto strains is needed, to ensure proper and timely implementation of control policies that may have a positive impact on public and occupational health.

Investigating Clinical Issues by Genotyping of Medically Important Fungi: Why and How?

Genotyping studies of medically important fungi have addressed elucidation of outbreaks, nosocomial transmissions, infection routes, and genotype-phenotype correlations, of which secondary resistance has been most intensively investigated. Two methods have emerged because of their high discriminatory power and reproducibility: multilocus sequence typing (MLST) and microsatellite length polymorphism (MLP) using short tandem repeat (STR) markers. MLST relies on single-nucleotide polymorphisms within the coding regions of housekeeping genes. STR polymorphisms are based on the number of repeats of short DNA fragments, mostly outside coding regions, and thus are expected to be more polymorphic and more rapidly evolving than MLST markers. There is no consensus on a universal typing system. Either one or both of these approaches are now available for Candida spp., Aspergillus spp., Fusarium spp., Scedosporium spp., Cryptococcus neoformans, Pneumocystis jirovecii, and endemic mycoses. The choice of the method and the number of loci to be tested depend on the clinical question being addressed. Next-generation sequencing is becoming the most appropriate method for fungi with no MLP or MLST typing available. Whatever the molecular tool used, collection of clinical data (e.g., time of hospitalization and sharing of similar rooms) is mandatory for investigating outbreaks and nosocomial transmission.

Simultaneous primary invasive cutaneous aspergillosis in two preterm twins: case report and review of the literature

Background

Primary invasive cutaneous aspergillosis is a rare fungal infection that occurs mostly in immunocompromised patients. Newborns of very low birth weight present a high risk for this type of infection due to an immaturity of the cutaneous barrier and of the immune system.

Case presentation

We describe here a case of simultaneous invasive cutaneous aspergillosis in two preterm twins. Two male preterm bichorionic biamniotic twins (A & B) were born at a general hospital by spontaneous normal delivery at 24 weeks and 6 days of gestation. They were transferred to our hospital where they receive surfactant, antibiotics and hydrocortisone. Six days later, twin A showed greenish lesions in the umbilical region. The spectrum of antibiotic therapy was broadened and fluconazole was added. The umbilical catheters of the two twins were removed and replaced by epicutaneo-cava venous catheters and the cultures were positive for Aspergillus fumigatus. Fluconazole was replaced in both twins by liposomal amphotericin B and the incubators were changed. The serum galactomannan was also positive for both twins. At day 10, yellowish lesions appeared in the abdominal region in twin B. He died on day 18 following complications related to his prematurity. Concerning the twin A, serum galactomannan was negative on day 30; liposomal amphotericin B was stopped 1 week later, with a relay by econazole (cream). His condition improved and on day 66 he was transferred for follow-up at the general hospital where he was born.

Conclusion

The source of contamination by A. fumigatus was not identified, but other similar cases from the literature include construction work at or near the hospital, oximeter sensors, latex finger stalls, non-sterile gloves, humidifying chambers of incubators, bedding and adhesive tapes. The skin fragility of preterm newborns is an excellent potential entry point for environmental fungal infections. These cases highlight the importance of suspecting primary cutaneous aspergillosis in extremely low birth weight neonates with rapidly progressive necrotic lesions.

Primary Cutaneous Aspergillosis in a Preterm Infant

Primary cutaneous aspergillosis is rare in premature infants. It requires combined medical and surgical strategies. Liposomal amphotericin B is recommended as first-line therapy, but salvage regimens with others antifungal agents, such as voriconazole, have been reported. Voriconazole's pharmacodynamics is unknown in this population. We report a case of severe toxicity to voriconazole in a preterm patient with primary cutaneous aspergillosis.

Simple and highly discriminatory VNTR-based multiplex PCR for tracing sources of Aspergillus flavus isolates

Aspergillus flavus is second only to A. fumigatus in causing invasive aspergillosis and it is the major agent responsible for fungal sinusitis, keratitis and endophthalmitis in many countries in the Middle East, Africa and Southeast Asia. Despite the growing challenge due to A. flavus, data on the molecular epidemiology of this fungus remain scarce. The objective of the present study was to develop a new typing method based on the detection of VNTR (Variable number tandem repeat) markers. Eight VNTR markers located on 6 different chromosomes (1, 2, 3, 5, 7 and 8) of A. flavus were selected, combined by pairs for multiplex amplifications and tested on 30 unrelated isolates and six reference strains. The Simpson index for individual markers ranged from 0.398 to 0.818. A combined loci index calculated with all the markers yielded an index of 0.998. The MLVA (Multiple Locus VNTR Analysis) technique proved to be specific and reproducible. In a second time, a total of 55 isolates from Chinese avian farms and from a Tunisian hospital have been evaluated. One major cluster of genotypes could be defined by using the graphing algorithm termed Minimum Spanning Tree. This cluster comprised most of the isolates collected in an avian farm in southern China. The MLVA technique should be considered as an excellent and cost-effective typing method that could be used in many laboratories without the need for sophisticated equipment.

Severe cutaneous aspergillosis in a premature neonate linked to nonsterile disposable glove contamination?

After having eliminated a dysfunction of the hospital's ventilation system and any other possible environmental reservoir, the investigation of a fatal case of primary cutaneous aspergillosis in a neonate with extremely low birth weight led to the conclusion that nonsterile disposable gloves kept stored in their native packages were the likely source of contamination.

Phylogeography of the cosmopolitan fungus Aspergillus flavus: is everything everywhere?

Aspergillus flavus is one of the most common fungal eukaryotes on the planet. It is notorious for production of aflatoxins, for causing aspergillosis in humans and animals, and as an opportunistic pathogen of animals and plants. Its role in marine habitats is unclear. Until now, little phylogeographic structure has been detected for the species, except at very local scales, and it appears to fit the classic dictum of microbial biogeography: Everything is everywhere. Here we use genetic relationships among isolates to determine phylogeographic structure, mating types, and differences in preferences for: marine vs. terrestrial habitats, various substrates, and clinical vs. nonclinical environments. Phylogenetic relationships among isolates were estimated using amplified fragment length polymorphisms (AFLPs) and mating types were determined for a worldwide sample of A. flavus isolates from diverse substrates and geographic locations. All isolates composed a single population, with no significant differentiation of marine vs. terrestrial isolates, clinical vs. environmental isolates, or association with substrate or geographic origin. There was evidence for local dominance of a single clade, probably clonal in origin and short-lived. The proportion of mating types was 1:1, supporting the hypothesis of recombination in natural populations. However, a high proportion of clinical isolates were MAT1-1 (85%), suggesting that a gene linked to the MAT1-1 idiomorph could play a role in pathogenicity. This study suggests that a more appropriate description of the phylogeography of A. flavus is 'everything is everywhere, but not all the time.'

A review molecular typing methods for Aspergillus flavus isolates

Aspergillus flavus is the second most important Aspergillus species causing human infections. The importance of this fungus increases in regions with a dry and hot climate. Small phylogenetic studies in Aspergillus flavus indicate that the morphological species contains several genetically isolated species. Different genotyping methods have been developed and employed in order to better understand the genetic and epidemiological relationships between environmental and clinical isolates. Understanding pathogen distribution and relatedness is essential for determining the epidemiology of nosocomial infections and aiding in the design of rational pathogen control methods. Typing techniques can also give us a deeper understanding of the colonization pattern in patients. Most of these studies focused on Aspergillus fumigatus because it is medically the most isolated species. To date, there has not been any publication exclusively reviewing the molecular typing techniques for Aspergillus flavus in the literature. This article reviews all these different available methods for this organism.

[Primary cutaneous aspergillosis complicated with invasive aspergillosis in an extremely preterm infant: case report and literature review]

Aspergillus is a ubiquitous fungus that can cause primary cutaneous aspergillosis in extremely low-birth-weight (ELBW) neonates, then be invasive and lead to death. ELBW neonates are particularly at risk because of decreased qualitative immune defenses and defects in the skin barrier. Broad-spectrum antimicrobial therapy and corticosteroids, often used in these patients, contribute to increased risk. We present a fatal case of primary cutaneous aspergillosis complicated with invasive aspergillosis, confirmed by autopsy, in an ELBW infant. The source of contamination was probably non-sterile disposable latex gloves used for neonatal care. The early recognition of this source led to its eviction for other hospitalized ELBW infants and no outbreak was observed.

Microsatellite typing to trace Aspergillus flavus infections in a hematology unit

Assessing the relatedness of strains isolated from patients and their environment is instrumental in documenting the source of preventable health care-associated life-threatening Aspergillus flavus human infection clusters. The present study aimed at identifying and selecting suitable microsatellite markers for A. flavus typing. This typing scheme was then applied to investigate the A. flavus epidemiology within a hematology unit in Sfax, Tunisia. Use of a combination of five markers made it possible to discern clusters of isolates and to substantiate the genetic diversity of A. flavus within clusters. Isolates from Tunisia and Marseille, France, displayed distinct haplotypes, indicating a highly significant geographical structuring of A. flavus. The typing of clinical and environmental A. flavus isolates in a hematology unit provided insights into its hospital epidemiology. From a heterogeneous genetic background, a cluster indicative of a clonal propagation episode within the unit could be identified. In two patients with invasive aspergillosis, the same genotype was found in clinical and environmental isolates, indicating hospital-acquired colonization and infection. In further studies, this novel microsatellite typing scheme might be instrumental in illuminating important epidemiological issues about A. flavus population genetics or epidemiology, including tracing the sources and routes of transmission.

Guidelines for the Prevention and Treatment of Opportunistic Infections among HIV-exposed and HIV-infected children: recommendations from CDC, the National Institutes of Health, the HIV Medicine Association of the Infectious Diseases Society of America, the Pediatric Infectious Diseases Society, and the American Academy of Pediatrics

This report updates and combines into one document earlier versions of guidelines for preventing and treating opportunistic infections (OIs) among HIV-exposed and HIV-infected children, last published in 2002 and 2004, respectively. These guidelines are intended for use by clinicians and other health-care workers providing medical care for HIV-exposed and HIV-infected children in the United States. The guidelines discuss opportunistic pathogens that occur in the United States and one that might be acquired during international travel (i.e., malaria). Topic areas covered for each OI include a brief description of the epidemiology, clinical presentation, and diagnosis of the OI in children; prevention of exposure; prevention of disease by chemoprophylaxis and/or vaccination; discontinuation of primary prophylaxis after immune reconstitution; treatment of disease; monitoring for adverse effects during treatment; management of treatment failure; prevention of disease recurrence; and discontinuation of secondary prophylaxis after immune reconstitution. A separate document about preventing and treating of OIs among HIV-infected adults and postpubertal adolescents (Guidelines for the Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents) was prepared by a working group of adult HIV and infectious disease specialists. The guidelines were developed by a panel of specialists in pediatric HIV infection and infectious diseases (the Pediatric Opportunistic Infections Working Group) from the U.S. government and academic institutions. For each OI, a pediatric specialist with content-matter expertise reviewed the literature for new information since the last guidelines were published; they then proposed revised recommendations at a meeting at the National Institutes of Health (NIH) in June 2007. After these presentations and discussions, the guidelines underwent further revision, with review and approval by the Working Group, and final endorsement by NIH, CDC, the HIV Medicine Association (HIVMA) of the Infectious Diseases Society of America (IDSA), the Pediatric Infectious Disease Society (PIDS), and the American Academy of Pediatrics (AAP). The recommendations are rated by a letter that indicates the strength of the recommendation and a Roman numeral that indicates the quality of the evidence supporting the recommendation so readers can ascertain how best to apply the recommendations in their practice environments. An important mode of acquisition of OIs, as well as HIV infection among children, is from their infected mother; HIV-infected women coinfected with opportunistic pathogens might be more likely than women without HIV infection to transmit these infections to their infants. In addition, HIV-infected women or HIV-infected family members coinfected with certain opportunistic pathogens might be more likely to transmit these infections horizontally to their children, resulting in increased likelihood of primary acquisition of such infections in the young child. Therefore, infections with opportunistic pathogens might affect not just HIV-infected infants but also HIV-exposed but uninfected infants who become infected by the pathogen because of transmission from HIV-infected mothers or family members with coinfections. These guidelines for treating OIs in children therefore consider treatment of infections among all children, both HIV-infected and uninfected, born to HIV-infected women. Additionally, HIV infection is increasingly seen among adolescents with perinatal infection now surviving into their teens and among youth with behaviorally acquired HIV infection. Although guidelines for postpubertal adolescents can be found in the adult OI guidelines, drug pharmacokinetics and response to treatment may differ for younger prepubertal or pubertal adolescents. Therefore, these guidelines also apply to treatment of HIV-infected youth who have not yet completed pubertal development. Major changes in the guidelines include 1) greater emphasis on the importance of antiretroviral therapy for preventing and treating OIs, especially those OIs for which no specific therapy exists; 2) information about the diagnosis and management of immune reconstitution inflammatory syndromes; 3) information about managing antiretroviral therapy in children with OIs, including potential drug--drug interactions; 4) new guidance on diagnosing of HIV infection and presumptively excluding HIV infection in infants that affect the need for initiation of prophylaxis to prevent Pneumocystis jirovecii pneumonia (PCP) in neonates; 5) updated immunization recommendations for HIV-exposed and HIV-infected children, including hepatitis A, human papillomavirus, meningococcal, and rotavirus vaccines; 6) addition of sections on aspergillosis; bartonella; human herpes virus-6, -7, and -8; malaria; and progressive multifocal leukodystrophy (PML); and 7) new recommendations on discontinuation of OI prophylaxis after immune reconstitution in children. The report includes six tables pertinent to preventing and treating OIs in children and two figures describing immunization recommendations for children aged 0--6 years and 7--18 years. Because treatment of OIs is an evolving science, and availability of new agents or clinical data on existing agents might change therapeutic options and preferences, these recommendations will be periodically updated and will be available at http://AIDSInfo.nih.gov.

Aspergillus flavus: an emerging non-fumigatus Aspergillus species of significance

Invasive aspergillosis is rare in immunocompetent people but contributes to significant morbidity and mortality in immunosuppressed patients. The majority (approximately 80%) of invasive Aspergillus infections is caused by Aspergillus fumigatus. The second most frequent (approximately 15-20%) pathogenic species is Aspergillus flavus and to a lesser extent, Aspergillus niger and Aspergillus terreus. Aspergillus flavus has emerged as a predominant pathogen in patients with fungal sinusitis and fungal keratitis in several institutions worldwide. To date, there has not been any publication exclusively reviewing the topic of A. flavus in the literature. This article reviews the microbiology, toxigenicity and epidemiology of A. flavus as well as describes the clinical characteristics, diagnosis and management of infections caused by this organism.

Molecular typing of Aspergillus species

Aspergillus species are widely distributed fungi that release large amounts of airborne conidia, which are dispersed in the environment. Several Aspergillus species have been described as human pathogens. Molecular techniques have been developed to investigate the epidemiological relation between environmental and clinical isolates. Several typing methods have been described for Aspergillus species, most of them with reference to Aspergillus fumigatus. Here, we summarise all the different available molecular typing techniques for Aspergillus. The performance of these techniques is evaluated with respect to their practical feasibility, and their interpretation and discriminatory power assessed. For A. fumigatus isolates, a large extent of genetic variability is demonstrated and therefore fingerprinting techniques with high discriminatory power and high reproducibility are required for this species. Afut1-restriction fragment length polymorphism and microsatellite typing showed the highest discriminatory power. In addition, the microsatellites show excellent reproducibility. Other typing techniques are still useful for smaller epidemiological problems and for less well-equipped laboratories.

Use of pyrosequencing to quantify incidence of a specific Aspergillus flavus strain within complex fungal communities associated with commercial cotton crops

Atoxigenic strains of Aspergillus flavus have been used as aflatoxin management tools on over 50,000 hectares of commercial crops since 2000. To assess treatment efficacy, atoxigenic strain incidence is routinely monitored by vegetative compatibility analyses (VCA) that require culturing, generation of auxotrophs, and complementation with tester mutants. Two pyrosequencing assays (PA) that require no culturing were developed for monitoring incidences of atoxigenic strains on ginned cottonseed. The assays, which quantify frequencies of characteristic single nucleotide polymorphisms (SNPs) in the aflR and pksA genes, were validated against standard VCA on cottonseed collected from commercial gins in South Texas, Arizona, and Southern California where the atoxigenic strain AF36 is used to manage aflatoxin contamination. Cottonseed washings were subjected to both VCA and PA. PA was performed directly on DNA isolated from particulates pelleted from the wash water by centrifugation. Addition of CaCl(2) and diatomaceous earth prior to pelleting increased the amount of DNA isolated. Accuracy and reproducibility of the PA were contrasted with those for the VCA that has been used for over a decade. Correlation coefficients between VCA and PA indicated good correspondence between the results from the two assays (r = 0.91 for aflR assay and r = 0.80 for pksA assay). PAs were highly variable for samples with low incidences of A. flavus due to variability in the initial polymerase chain reaction step. This held for both DNA isolated from cottonseed washes and for mixtures of purified DNA. For samples yielding low quantities of A. flavus DNA, averaging of results from 4 to 5 replicates was required to achieve acceptable correlations with VCA. Pyrosequencing has the potential to become a powerful tool for monitoring atoxigenic strains within complex A. flavus communities without limitations imposed by traditional culturing methods.

DNA fingerprinting analysis of Petromyces alliaceus (Aspergillus section Flavi)

The objective of this study was to evaluate the ability of the Aspergillus flavus pAF28 DNA probe to produce DNA fingerprints for distinguishing among genotypes of Petromyces alliaceus (Aspergillus section Flavi), a fungus considered responsible for the ochratoxin A contamination that is occasionally observed in California fig orchards. P. alliaceus (14 isolates), Petromyces albertensis (one isolate), and seven species of Aspergillus section Circumdati (14 isolates) were analyzed by DNA fingerprinting using a repetitive sequence DNA probe pAF28 derived from A. flavus. The presence of hybridization bands with the DNA probe and with the P. alliaceus or P. albertensis genomic DNA indicates a close relationship between A. flavus and P. alliaceus. Twelve distinct DNA fingerprint groups or genotypes were identified among the 15 isolates of Petromyces. Conspecificity of P. alliaceus and P. albertensis is suggested based on DNA fingerprints. Species belonging to Aspergillus section Circumdati hybridized only slightly at the 7.0-kb region with the repetitive DNA probe, unlike the highly polymorphic hybridization patterns obtained from P. alliaceus and A. flavus, suggesting very little homology of the probe to Aspergillus section Circum dati genomic DNA. The pAF28 DNA probe offers a tool for typing and monitoring specific P. alliaceus clonal populations and for estimating the genotypic diversity of P. alliaceus in orchards, vineyards, or crop fields.

Molecular typing of aspergilli: Recent developments and outcomes

Aspergillus spp. have been the subject of numerous epidemiological studies. The most useful typing techniques are DNA based methods including the random amplified polymorphic DNA technique, microsatellite length polymorphisms, restriction fragment length polymorphism (RFLP) analysis using retrotransposon-like sequences as probes, and multilocus sequence typing. The results of typing clinical isolates indicate that most of the invasive aspergillosis (IA) patients were infected by a single strain. Genetic analysis could not discriminate between clinical and environmental isolates of Aspergillus. fumigatus, indicating that every strain present in the environment is a potential pathogen if it encounters the appropriate host. The source of infection can also be monitored by typing. Typing studies led to the discovery of a new pathogenic species, A. lentulus, and to the identification of several species not known previously to be pathogenic. Typing studies revealed the existence of two genetically isolated groups within a global A. fumigatus population. Aspergillus fumigatus was found to be the first example of a true cosmopolitan fungus. Additionally, the results obtained in several studies support the premise that recombination played an important role in A. fumigatus populations. The discovery of functional mating type genes in A. fumigatus indicates that past or recent sexual processes could be responsible for the observed recombining population structure.

Primary cutaneous opportunistic mold infections in a pediatric population

OBJECTIVE

We sought to describe the features of cutaneous opportunistic mold infections in a general pediatric population.

METHODS

Computerized pathology records from Texas Children's Hospital in Houston during the years 1991 to 2000 were used to identify any biopsy specimens of skin diagnosed as having fungus or mold. The corresponding medical records were reviewed to identify cases of cutaneous opportunistic mold infections. Cases were limited to those with histologic confirmation of hyphae within the dermis or extending to the dermis.

RESULTS

A total of 11 cases in neonates and 22 cases in children and adolescents were identified. Prematurity and low birth weight were the major risk factors in the neonatal population. The nonneonatal cases mainly occurred in those with malignancies or undergoing transplantation. Mortality in neonates was 64%, but decreased to 18% in the nonneonatal population.

CONCLUSION

Our overview of cutaneous infection by opportunistic molds in a pediatric population highlights the risk factors, causative organisms, and outcome of this group of infections. Even in the presence of severe compromise of the immune system, children with primary cutaneous mold infections had a favorable outcome with appropriate diagnosis and therapy.

Mutations in the cyp51A gene and susceptibility to itraconazole in Aspergillus fumigatus serially isolated from a patient with lung aspergilloma

OBJECTIVES

To monitor changes in itraconazole susceptibility of isolates from a patient undergoing treatment for pulmonary Aspergillus infection and relate these changes to genotypic/phenotypic alterations.

METHODS

Six Aspergillus fumigatus isolates were serially recovered from the patient. Itraconazole MICs were determined by Etest and NCCLS methodology. Growth characteristics and phenotype were monitored. Molecular analysis included random amplified polymorphic DNA (RAPD) assay and sequencing of the cyp51A gene.

RESULTS

The MIC of itraconazole against the first isolate before treatment was 0.25 mg/L; the MIC against the second isolate, recovered after 6 months of itraconazole therapy, was >16 mg/L; and that against the third isolate, obtained 2 months after discontinuation of the therapy, was 0.5 mg/L. The MIC against the last three isolates, acquired after restoration of itraconazole therapy for 4-7 months, was >16 mg/L. The six isolates shared identical band patterns of RAPD assay using four primers and the same sequence in intertranscribed spacers (ITS). Therefore, the six isolates were likely to be the same strain of A. fumigatus, and mutations involving itraconazole resistance possibly occurred in these isolates after prolonged itraconazole therapy. Sequencing of the cyp51A gene in the coding region revealed a mutation of M220I in cytochrome P450 sterol 14-alpha-demethylase in the second resistant isolate and a mutation of G54R in the last three resistant isolates. Expression changes of some pump genes, such as MDR3, may also, in part, be related to the resistance to itraconazole.

CONCLUSIONS

We conclude that resistance of A. fumigatus to itraconazole occurred in a patient treated with the drug, and the resistance may result from mutations in the cyp51A gene-the gene encoding the target enzyme for itraconazole.

Molecular epidemiology of invasive stomatitis due to Aspergillus flavus in patients with acute leukemia

BACKGROUND

Invasive oral aspergillosis is a rare complication and only little information on the epidemiology of Aspergillus flavus infection is available. We present here the molecular analysis of the epidemiology of invasive stomatitis due to Aspergillus flavus in patients with acute leukemia.

METHODS

During a 5-year period (1992-1996), six isolates of A. flavus were obtained from leukemic patients with invasive Aspergillus stomatitis. Random amplification of polymorphic DNA (RAPD) with three different PCR primers was carried out to investigate the DNA typing of the isolates.

RESULTS

The molecular analysis using RAPD revealed that three isolates of A. flavus obtained in 1992 from three patients were of the same type, whereas each of the isolates from the other three patients had a distinct unique band, resulting in four groups of A. flavus.

CONCLUSION

As the three patients with invasive oral aspergillosis detected in 1992 were infected by a single strain of A. flavus, the strain was suspected to have caused a nosocomial outbreak of invasive oral aspergillosis in the hematology unit.

Evaluation of performance of four genotypic methods for studying the genetic epidemiology of Aspergillus fumigatus isolates

In the present investigation, 49 Aspergillus fumigatus isolates obtained from four nosocomial outbreaks were typed by Afut1 restriction fragment length polymorphism (RFLP) analysis and three PCR-based molecular typing methods: random amplified polymorphic DNA (RAPD) analysis, sequence-specific DNA primer (SSDP) analysis, and polymorphic microsatellite markers (PMM) analysis. The typing methods were evaluated with respect to discriminatory power (D), reproducibility, typeability, ease of use, and ease of interpretation to determine their performance and utility for outbreak and surveillance investigations. Afut1 RFLP analysis detected 40 types. Thirty types were observed by RAPD analysis. PMM analysis detected 39 allelic types, but SSDP analysis detected only 14 types. All four methods demonstrated 100% typeability. PMM and RFLP analyses had comparable high degrees of discriminatory power (D = 0.989 and 0.988, respectively). The discriminatory power of RAPD analysis was slightly lower (D = 0.971), whereas SSDP analysis had the lowest discriminatory power (D = 0.889). Overall, SSDP analysis was the easiest method to interpret and perform. The profiles obtained by PMM analysis were easier to interpret than those obtained by RFLP or RAPD analysis. Bands that differed in staining intensity or that were of low intensity were observed by RAPD analysis, making interpretation more difficult. The reproducibilities with repeated runs of the same DNA preparation or with different DNA preparations of the same strain were high for all the methods. A high degree of genetic variation was observed in the test population, but isolates were not always similarly divided by each method. Interpretation of band profiles requires understanding of the molecular mechanisms responsible for genetic alternations. PMM analysis and Afut1 RFLP analysis, or their combination, appear to provide the best overall discriminatory power, reproducibility, ease of interpretation, and ease of use. This investigation will aid in planning epidemiologic and surveillance studies of A. fumigatus.

Epidemiology and Prevention of Invasive Aspergillosis

Aspergillus species are the most common causes of invasive mold infections in immunocompromised persons. This review examines the available information regarding the rising incidence of invasive aspergillosis in different high-risk groups, including persons with acute leukemia, hematopoietic stem cell transplant recipients, and liver and lung transplant recipients. The risk factors for infection in these groups are discussed. Because Aspergillus species are widespread in the environment, it is difficult to link specific sources and exposures to the development of human infections. However, molecular strain typing and other studies indicate that a significant number of Aspergillus infections are now being acquired outside the health care setting, either before patients are admitted to hospital, or after they have been discharged. The role of environmental control measures and antifungal drug prophylaxis in the prevention of hospital- and community-acquired aspergillosis is discussed.

Nosocomial infections in the neonatal intensive care unit

Nosocomial infections are significant causes of morbidity and mortality in patients who require newborn intensive care. The most common bacterial pathogens are Gram-positive bacteria, including Staphylococcus epidermidis, Staphylococcus aureus, and Enterococcus species. Gram-negative enteric bacilli and Gram-negative environmental bacteria are involved in outbreaks and occasional cases of nosocomial infection. The incidence of fungal infection has increased over the past 10 years; fungemia is the most commonly recognized infection. Surveillance for nosocomial infection is essential to identify outbreaks and detect unsuspected reservoirs of pathogens. A variety of molecular techniques can be used to determine the genetic relatedness of pathogens. Prevention of infection requires the identification of contaminated equipment, education regarding infection control methods including hand washing, and the judicious use of antimicrobial agents.