Scedosporiosis and lomentosporiosis: modern perspectives on these difficult-to-treat rare mold infections.

SUMMARYAlthough Scedosporium species and Lomentospora prolificans are uncommon causes of invasive fungal diseases (IFDs), these infections are associated with high mortality and are costly to treat with a limited armamentarium of antifungal drugs. In light of recent advances, including in the area of new antifungals, the present review provides a timely and updated overview of these IFDs, with a focus on the taxonomy, clinical epidemiology, pathogenesis and host immune response, disease manifestations, diagnosis, antifungal susceptibility, and treatment. An expansion of hosts at risk for these difficult-to-treat infections has emerged over the last two decades given the increased use of, and broader population treated with, immunomodulatory and targeted molecular agents as well as wider adoption of antifungal prophylaxis. Clinical presentations differ not only between genera but also across the different Scedosporium species. L. prolificans is intrinsically resistant to most currently available antifungal agents, and the prognosis of immunocompromised patients with lomentosporiosis is poor. Development of, and improved access to, diagnostic modalities for early detection of these rare mold infections is paramount for timely targeted antifungal therapy and surgery if indicated. New antifungal agents (e.g., olorofim, fosmanogepix) with novel mechanisms of action and less cross-resistance to existing classes, availability of formulations for oral administration, and fewer drug-drug interactions are now in late-stage clinical trials, and soon, could extend options to treat scedosporiosis/lomentosporiosis. Much work remains to increase our understanding of these infections, especially in the pediatric setting. Knowledge gaps for future research are highlighted in the review.

Candida auris PCR for high-throughput infection control screening.

Candida auris has significant implications for infection control due to its multidrug resistance and spread in healthcare settings. Current culture-based screening methods are laborious and risk muco-cutaneous colonisation of laboratory staff. We describe the adaptation of a published real-time PCR for the identification of C. auris in skin swabs for high-throughput infection control screening. Two published primer and probe sets were analysed utilising serial 10-fold dilutions of 15 C. auris strains to assess the PCR limit of detection. One primer and probe set was compatible with our laboratory workflow and was selected for further development yielding a limit of detection of 1 colony forming unit per reaction. Non-C. auris isolates as well as routine skin swabs (n = 100) were tested by culture and PCR to assess specificity, where no cross-reactivity was detected. Skin swabs from a proven C. auris case (n = 6) were all both culture positive and PCR positive, while surveillance swabs from close contacts (n = 46) were all both culture negative and PCR negative. Finally, the use of a lysis buffer comprising 4 m guanidinium thiocyanate rendered swab-equivalent quantities of C. auris non-viable, providing assurance of the safety benefit of PCR over culture. The development of a PCR assay for high-throughput infection control screening is a promising method for rapid detection of C. auris with utility in an outbreak setting. LAY SUMMARY: Candida auris, a difficult to treat yeast-like fungus, has spread through healthcare facilities globally, posing a serious threat to the health of patients. We evaluated a PCR-based method suitable for screening large numbers of patient samples to rapidly and accurately detect C. auris.

Candida auris susceptibility on surfaces coated with the antifungal drug caspofungin.

Candida auris is known to survive for weeks on solid material surfaces. Its longevity contributes to medical device contamination and spread through healthcare facilities. We fabricated antifungal surface coatings by coating plastic and glass surfaces with a thin polymer layer to which the antifungal drug caspofungin was covalently conjugated. Caspofungin-susceptible and -resistant C. auris strains were inhibited on these surfaces by 98.7 and 81.1%, respectively. Cell viability studies showed that this inhibition was fungicidal. Our findings indicate that C. auris strains can be killed on contact when exposed to caspofungin that is reformulated as a covalently-bound surface layer. LAY SUMMARY: Candida auris is pathogenic, multidrug resistant yeast with the ability to survive on surfaces and remain transmissible for long periods of time in healthcare settings. In this study, we have prepared an antifungal surface coating and demonstrated its ability to kill adhering C. auris cells on contact.

Mycetoma caused by Microsporum canis in a patient with renal transplant: A case report and review of the literature.

Microsporum canis is a dermatophyte known to cause superficial skin infections. In immunocompromised patients, it can lead to invasive dermatophytosis. We present a case of biopsy-proven left knee mycetoma caused by M canis in a renal transplant patient. Identification of M canis was achieved via sequencing of the internal transcribed spacer regions. Treatment involved surgical debridement, oral posaconazole, and reduction in immunosuppression. In addition, we provide a review of current literature on invasive M canis infections.

Consensus guidelines for antifungal stewardship, surveillance and infection prevention, 2021.

Invasive fungal diseases (IFD) are serious infections associated with high mortality, particularly in immunocompromised patients. The prescribing of antifungal agents to prevent and treat IFD is associated with substantial economic burden on the health system, high rates of adverse drug reactions, significant drug-drug interactions and the emergence of antifungal resistance. As the population at risk of IFD continues to grow due to the increased burden of cancer and related factors, the need for hospitals to employ antifungal stewardship (AFS) programmes and measures to monitor and prevent infection has become increasingly important. These guidelines outline the essential components, key interventions and metrics, which can help guide implementation of an AFS programme in order to optimise antifungal prescribing and IFD management. Specific recommendations are provided for quality processes for the prevention of IFD in the setting of outbreaks, during hospital building works, and in the context of Candida auris infection. Recommendations are detailed for the implementation of IFD surveillance to enhance detection of outbreaks, evaluate infection prevention and prophylaxis interventions and to allow benchmarking between hospitals. Areas in which information is still lacking and further research is required are also highlighted.

Structure, Mechanism, and Inhibition of Aspergillus fumigatus Thioredoxin Reductase.

Aspergillus fumigatus infections are associated with high mortality rates and high treatment costs. Limited available antifungals and increasing antifungal resistance highlight an urgent need for new antifungals. Thioredoxin reductase (TrxR) is essential for maintaining redox homeostasis and presents as a promising target for novel antifungals. We show that ebselen [2-phenyl-1,2-benzoselenazol-3(2H)-one] is an inhibitor of A. fumigatus TrxR (Ki = 0.22 µM) and inhibits growth of Aspergillus spp., with in vitro MIC values of 16 to 64 µg/ml. Mass spectrometry analysis demonstrates that ebselen interacts covalently with a catalytic cysteine of TrxR, Cys148. We also present the X-ray crystal structure of A. fumigatus TrxR and use in silico modeling of the enzyme-inhibitor complex to outline key molecular interactions. This provides a scaffold for future design of potent and selective antifungal drugs that target TrxR, improving the potency of ebselen toward inhbition of A. fumigatus growth.

cyp51A Mutations, Extrolite Profiles, and Antifungal Susceptibility in Clinical and Environmental Isolates of the Aspergillus viridinutans Species Complex.

The past decade has seen an increase in aspergillosis in humans and animals due to Aspergillus viridinutans species complex members. Azole resistance is common to these infections, carrying a poor prognosis. cyp51A gene mutations are the main cause of acquired azole resistance in Aspergillus fumigatus This study aimed to determine if the azole-resistant phenotype in A. viridinutans complex members is associated with cyp51A mutations or extrolite profiles. The cyp51A gene of clinical and environmental isolates was amplified using novel primers, antifungal susceptibility was tested using the Clinical and Laboratory Standards Institute methodology, and extrolite profiling was performed using agar plug extraction. Very high azole MICs were detected in 84% of the isolates (31/37). The MICs of the newer antifungals luliconazole and olorofim (F901318) were low for all isolates. cyp51A sequences revealed 113 nonsynonymous mutations compared to the sequence of wild-type A. fumigatus M172A/V and D255G, previously associated with A. fumigatus azole resistance, were common among all isolates but were not correlated with azole MICs. Two environmental isolates with nonsusceptibility to itraconazole and high MICs of voriconazole and isavuconazole harbored G138C, previously associated with azole-resistant A. fumigatus Some novel mutations were identified only among isolates with high azole MICs. However, cyp51A homology modeling did not cause a significant protein structure change for these mutations. There was no correlation between extrolite patterns and susceptibility. For A. viridinutans complex isolates, cyp51A mutations and the extrolites that they produced were not major causes of antifungal resistance. Luliconazole and olorofim show promise for treating azole-resistant infections caused by these cryptic species.

Trends in Deaths Due to Syphilis, United States, 1968-2015.

BACKGROUND: Before penicillin, the syphilis case-fatality rate was 10% within 40 years. Late complications, such as cardiovascular syphilis, were still common in the 1950s but now seem quite rare even though some infections likely go undetected. We studied trends in syphilis mortality as an indicator of trends in severe complications of syphilis. METHODS: We assessed underlying cause of death from US death certificates for 1968 to 2015. We examined death trends by type of syphilis (cardiovascular, neuro, congenital, other). We compared trends in deaths with trends in primary and secondary syphilis from national STD surveillance data. RESULTS: During 1968 to 2015, there were 6498 deaths attributed to syphilis, 4149 males and 2349 females. Annual syphilis deaths decreased from 586 in 1968 to 94 in 1984, then leveled off to between 24 and 46 since 1998. Between 1968 and 2015, the decrease in annual cardiovascular syphilis deaths (from 338 to 3) exceeded the decrease in annual neurosyphilis deaths (from 191 to 33). Congenital syphilis deaths (which do not include stillbirths) generally decreased from 28 to 2 per year. An increase in primary and secondary syphilis among women in the late 1980s was accompanied by a 4-fold increase in congenital syphilis deaths (from 9 in 1986 to 35 in 1990), but there was no subsequent increase in syphilis deaths among women. CONCLUSIONS: Adults now rarely die from syphilis. Increases in infections in the late 1980s did not lead to an increase in adult syphilis deaths. Congenital syphilis deaths still increase when syphilis increases among women.

Increasing Syphilis Diagnoses Among Females Giving Birth in US Hospitals, 2010-2014.

BACKGROUND: National trends in syphilis rates among females delivering newborns are not well characterized. We assessed 2010-2014 trends in syphilis diagnoses documented on discharge records and associated factors among females who have given birth in US hospitals. METHODS: We calculated quarterly trends in syphilis rates (per 100,000 deliveries) by using International Classification of Diseases, Ninth Revision, Clinical Modification codes on delivery discharge records from the National Inpatient Sample. Changes in trends were determined by using Joinpoint software. We estimated relative risks (RR) to assess the association of syphilis diagnoses with race/ethnicity, age, insurance status, household income, and census region. RESULTS: Overall, estimated syphilis rates decreased during 2010-2012 at 1.0% per quarter (P < 0.001) and increased afterward at 1.8% (P < 0.001). The syphilis rate increase was statistically significant across all sociodemographic groups and all US regions, with substantial increases identified among whites (35.2% per quarter; P < 0.001) and Medicaid recipients (15.1%; P < 0.001). In 2014, the risk of syphilis diagnosis was greater among blacks (RR, 13.02; 95% confidence interval [CI], 9.46-17.92) or Hispanics (RR, 4.53; 95% CI, 3.19-6.42), compared with whites; Medicaid recipients (RR, 4.63; 95% CI, 3.38-6.33) or uninsured persons (RR, 2.84; 95% CI, 1.74-4.63), compared with privately insured patients; females with the lowest household income (RR, 5.32; 95% CI, 3.55-7.97), compared with the highest income; and females in the South (RR, 2.42; 95% CI, 1.66-3.53), compared with the West. CONCLUSIONS: Increasing syphilis rates among pregnant females of all backgrounds reinforce the importance of prenatal screening and treatment.

Increased Methamphetamine, Injection Drug, and Heroin Use Among Women and Heterosexual Men with Primary and Secondary Syphilis - United States, 2013-2017.

During 2013-2017, the national annual rate of reported primary and secondary (P&S) syphilis cases in the United States increased 72.7%, from 5.5 to 9.5 cases per 100,000 population (1). The highest rates of P&S syphilis are seen among gay, bisexual, and other men who have sex with men (collectively referred to as MSM) (2), and MSM continued to account for the majority of cases in 2017 (1). However, during 2013-2017, the P&S syphilis rate among women increased 155.6% (from 0.9 to 2.3 cases per 100,000 women), and the rate among all men increased 65.7% (from 10.2 to 16.9 cases per 100,000 men), indicating increasing transmission between men and women in addition to increasing transmission between men (1). To further understand these trends, CDC analyzed national P&S syphilis surveillance data for 2013-2017 and assessed the percentage of cases among women, men who have sex with women only (MSW), and MSM who reported drug-related risk behaviors during the past 12 months. Among women and MSW with P&S syphilis, reported use of methamphetamine, injection drugs, and heroin more than doubled during 2013-2017. In 2017, 16.6% of women with P&S syphilis used methamphetamine, 10.5% used injection drugs, and 5.8% used heroin during the preceding 12 months. Similar trends were seen among MSW, but not among MSM. These findings indicate that a substantial percentage of heterosexual syphilis transmission is occurring among persons who use these drugs, particularly methamphetamine. Collaboration between sexually transmitted disease (STD) control programs and partners that provide substance use disorder services will be important to address recent increases in heterosexual syphilis.

Identification of multiple species and subpopulations among Australian clinical Sporothrix isolates using whole genome sequencing.

Whole genome sequencing (WGS) was used to demonstrate the wide genetic variability within Sporothrix schenckii sensu lato and establish that there are two main species of Sporothrix within Australian clinical isolates-S. schenckii sensu stricto and Sporothrix globosa. We also demonstrated southwest Western Australia contained genetically similar S. schenckii ss strains that are distinct from strains isolated in the eastern and northern states of Australia. Some genetic clustering by region was also noted for northern NSW, Queensland, and Northern Territory. Phylogenetic analysis of WGS data provided greater phylogenetic resolution compared to analysis of the calmodulin gene alone.

Diagnosis, management and prevention of Candida auris in hospitals: position statement of the Australasian Society for Infectious Diseases.

Candida auris is an emerging drug-resistant yeast responsible for hospital outbreaks. This statement reviews the evidence regarding diagnosis, treatment and prevention of this organism and provides consensus recommendations for clinicians and microbiologists in Australia and New Zealand. C. auris has been isolated in over 30 countries (including Australia). Bloodstream infections are the most frequently reported infections. Infections have crude mortality of 30-60%. Acquisition is generally healthcare-associated and risks include underlying chronic disease, immunocompromise and presence of indwelling medical devices. C. auris may be misidentified by conventional phenotypic methods. Matrix-assisted laser desorption ionisation time-of-flight mass spectrometry or sequencing of the internal transcribed spacer regions and/or the D1/D2 regions of the 28S ribosomal DNA are therefore required for definitive laboratory identification. Antifungal drug resistance, particularly to fluconazole, is common, with variable resistance to amphotericin B and echinocandins. Echinocandins are currently recommended as first-line therapy for infection in adults and children ≥2 months of age. For neonates and infants <2 months of age, amphotericin B deoxycholate is recommended. Healthcare facilities with C. auris should implement a multimodal control response. Colonised or infected patients should be isolated in single rooms with Standard and Contact Precautions. Close contacts, patients transferred from facilities with endemic C. auris or admitted following stay in overseas healthcare institutions should be pre-emptively isolated and screened for colonisation. Composite swabs of the axilla and groin should be collected. Routine screening of healthcare workers and the environment is not recommended. Detergents and sporicidal disinfectants should be used for environmental decontamination.

Multi-triazole-resistant Aspergillus fumigatus infections in Australia.

The emergence of triazole resistance, including multi-triazole-resistant Aspergillus fumigatus is being reported around the world, but there has been little evidence of this problem to date in Australia. Here we describe a retrospective search of antifungal susceptibility results of all Australian clinical A. fumigatus isolates referred to the National Mycology Reference Centre, Adelaide, Australia between 2000 and 2013, yielding 13 isolates with elevated minimum inhibitory concentrations to itraconazole, posaconazole and/or voriconazole. Four isolates were found to be Aspergillus lentulus, a closely related, morphologically similar species known to have reduced susceptibility to triazoles. Analysis of the cyp51A gene of nine confirmed A. fumigatus isolates revealed two carrying the TR34 /L98H mutation, one apparently locally acquired in 2004, and the other probably acquired abroad in 2012. Four isolates possessed the G54R, F46Y, Y431S and G448S mutations, respectively, whereas three isolates did not possess known cyp51A resistance mutations, raising the possibility of other, undetected resistance mechanisms. Routine antifungal susceptibility testing is definitively recommended in patients on long term and sub-therapeutic triazole therapy with breakthrough Aspergillus infection and recommended for all clinically relevant A. fumigatus isolates.

Trade-offs of different poliovirus vaccine options for outbreak response in the United States and other countries that only use inactivated poliovirus vaccine (IPV) in routine immunization.

Delays in achieving polio eradication have led to ongoing risks of poliovirus importations that may cause outbreaks in polio-free countries. Because of the low, but non-zero risk of paralysis with oral poliovirus vaccines (OPVs), countries that achieve and maintain high national routine immunization coverage have increasingly shifted to exclusive use of inactivated poliovirus vaccine (IPV) for all preventive immunizations. However, immunization coverage within countries varies, with under-vaccinated subpopulations potentially able to sustain transmission of imported polioviruses and experience local outbreaks. Due to its cost, ease-of-use, and ability to induce mucosal immunity, using OPV as an outbreak control measure offers a more cost-effective option in countries in which OPV remains in use. However, recent polio outbreaks in IPV-only countries raise questions about whether and when IPV use for outbreak response may fail to stop poliovirus transmission and what consequences may follow from using OPV for outbreak response in these countries. We systematically reviewed the literature to identify modeling studies that explored the use of IPV for outbreak response in IPV-only countries. In addition, applying a model of the 2022 type 2 poliovirus outbreak in New York, we characterized the implications of using different OPV formulations for outbreak response instead of IPV. We also explored the hypothetical scenario of the same outbreak except for type 1 poliovirus instead of type 2. We find that using IPV for outbreak response will likely only stop outbreaks for polioviruses of relatively low transmission potential in countries with very high overall immunization coverage, seasonal transmission dynamics, and only if IPV immunization interventions reach some unvaccinated individuals. Using OPV for outbreak response in IPV-only countries poses substantial risks and challenges that require careful consideration, but may represent an option to consider for some outbreaks in some populations depending on the properties of the available vaccines and coverage attainable.

Multi-Locus Microsatellite Typing of Colonising and Invasive Aspergillus fumigatus Isolates from Patients Post Lung Transplantation and with Chronic Lung Disease.

Aspergillus fumigatus can cause different clinical manifestations/phenotypes in lung transplant (LTx) recipients and patients with chronic respiratory diseases. It can also precipitate chronic lung allograft dysfunction (CLAD) in LTx recipients. Many host factors have been linked with the severity of A. fumigatus infection, but little is known about the contribution of different A. fumigatus strains to the development of different phenotypes and CLAD. We used multi-locus microsatellite typing (MLMT) to determine if there is a relationship between strain (i.e., genotype) and phenotype in 60 patients post LTx or with chronic respiratory disease across two time periods (1 November 2006-31 March 2009 and 1 November 2015-30 June 2017). The MLMT (STRAf) assay was highly discriminatory (Simpson's diversity index of 0.9819-0.9942) with no dominant strain detected. No specific genotype-phenotype link was detected, but several clusters and related strains were associated with invasive aspergillosis (IA) and colonisation in the absence of CLAD. Host factors were linked to clinical phenotypes, with prior lymphopenia significantly more common in IA cases as compared with A. fumigatus-colonised patients (12/16 [75%] vs. 13/36 [36.1%]; p = 0.01), and prior Staphylococcus aureus infection was a significant risk factor for the development of IA (odds ratio 13.8; 95% confidence interval [2.01-279.23]). A trend toward a greater incidence of CMV reactivation post-A. fumigatus isolation was observed (0 vs. 5; p = 0.06) in LTx recipients. Further research is required to determine the pathogenicity and immunogenicity of specific A. fumigatus strains.

Fungal Nomenclature: Managing Change is the Name of the Game.

Fungal species have undergone and continue to undergo significant nomenclatural change, primarily due to the abandonment of dual species nomenclature in 2013 and the widespread application of molecular technologies in taxonomy allowing correction of past classification errors. These have effected numerous name changes concerning medically important species, but by far the group causing most concern are the Candida yeasts. Among common species, Candida krusei, Candida glabrata, Candida guilliermondii, Candida lusitaniae, and Candida rugosa have been changed to Pichia kudriavzevii, Nakaseomyces glabrata, Meyerozyma guilliermondii, Clavispora lusitaniae, and Diutina rugosa, respectively. There are currently no guidelines for microbiology laboratories on implementing changes, and there is ongoing concern that clinicians will dismiss or misinterpret laboratory reports using unfamiliar species names. Here, we have outlined the rationale for name changes across the major groups of clinically important fungi and have provided practical recommendations for managing change.

An update on current and novel molecular diagnostics for the diagnosis of invasive fungal infections.

BACKGROUND: Invasive fungal infections cause millions of infections annually, but diagnosis remains challenging. There is an increased need for low-cost, easy to use, highly sensitive and specific molecular assays that can differentiate between colonized and pathogenic organisms from different clinical specimens. AREAS COVERED: We reviewed the literature evaluating the current state of molecular diagnostics for invasive fungal infections, focusing on current and novel molecular tests such as polymerase chain reaction (PCR), digital PCR, high-resolution melt (HRM), and metagenomics/next generation sequencing (mNGS). EXPERT OPINION: PCR is highly sensitive and specific, although performance can be impacted by prior/concurrent antifungal use. PCR assays can identify mutations associated with antifungal resistance, non-Aspergillus mold infections, and infections from endemic fungi. HRM is a rapid and highly sensitive diagnostic modality that can identify a wide range of fungal pathogens, including down to the species level, but multiplex assays are limited and HRM is currently unavailable in most healthcare settings, although universal HRM is working to overcome this limitation. mNGS offers a promising approach for rapid and hypothesis-free diagnosis of a wide range of fungal pathogens, although some drawbacks include limited access, variable performance across platforms, the expertise and costs associated with this method, and long turnaround times in real-world settings.

Epidemiology, management and outcomes of Cryptococcus gattii infections: A 22-year cohort.

BACKGROUND: Cryptococcus gattii is a globally endemic pathogen causing disease in apparently immune-competent hosts. We describe a 22-year cohort study from Australia's Northern Territory to evaluate trends in epidemiology and management, and outcome predictors. METHODS: A retrospective cohort study of all C. gattii infections at the northern Australian referral hospital 1996-2018 was conducted. Cases were defined as confirmed (culture-positive) or probable. Demographic, clinical and outcome data were extracted from medical records. RESULTS: 45 individuals with C. gattii infection were included: 44 Aboriginal Australians; 35 with confirmed infection; none HIV positive out of 38 tested. Multifocal disease (pulmonary and central nervous system) occurred in 20/45 (44%). Nine people (20%) died within 12 months of diagnosis, five attributed directly to C. gattii. Significant residual disability was evident in 4/36 (11%) survivors. Predictors of mortality included: treatment before the year 2002 (4/11 versus 1/34); interruption to induction therapy (2/8 versus 3/37) and end-stage kidney disease (2/5 versus 3/40). Prolonged antifungal therapy was the standard approach in this cohort, with median treatment duration being 425 days (IQR 166-715). Ten individuals had adjunctive lung resection surgery for large pulmonary cryptococcomas (median diameter 6cm [range 2.2-10cm], versus 2.8cm [1.2-9cm] in those managed non-operatively). One died post-operatively, and 7 had thoracic surgical complications, but ultimately 9/10 (90%) treated surgically were cured compared with 10/15 (67%) who did not have lung surgery. Four patients were diagnosed with immune reconstitution inflammatory syndrome which was associated with age <40 years, brain cryptococcomas, high cerebrospinal fluid pressure, and serum cryptococcal antigen titre >1:512. CONCLUSION: C. gattii infection remains a challenging condition but treatment outcomes have significantly improved over 2 decades, with eradication of infection the norm. Adjunctive surgery for the management of bulky pulmonary C. gattii infection appears to increase the likelihood of durable cure and likely reduces the required duration of antifungal therapy.