Presentation, anagement, and outcomes of norovirus in adult and pediatric solid organ and hematopoietic stem cell transplant recipients: A multicenter, retrospective study.

BACKGROUND: Norovirus (NoV) can cause chronic relapsing and remitting diarrhea in immunocompromised patients.  Few multicenter studies have described the clinical course, outcomes, and complications of chronic NoV in transplant recipients. METHODS: A multicenter retrospective study of adult and pediatric SOT and HSCT recipients diagnosed with NoV between November 1, 2017, and February 28, 2021. Data were obtained from electronic medical records (EMR) and entered into a central REDCap database. Descriptive statistics were calculated. RESULTS: A total of 280 NoV+ patients were identified across eight sites. The majority were adults (74.1%) and SOT recipients (91.4%). Initial diagnosis of NoV occurred a median of 36 months post-Tx (IQR [15.0, 90.0]). Most NoV cases had >3 diarrheal episodes daily (66.0%), nausea and vomiting (60.1%). Duration of diarrhea varied greatly (median = 10 days, mean = 85.9 days, range (1, 2100)). 71.3% were hospitalized. Adjustment of immunosuppression, including reduction and discontinuation of mToR inhibitor, CNI, and/or MMF, was the most common management intervention for NoV. Other therapies resulted only in temporary improvement. Four patients died within 30 days and three others died by 180 days postdiagnosis. Clinically significant renal dysfunction was observed in 12.5% by 30 days and 21.4% by 180 days post-NoV diagnosis. CONCLUSION: In HSCT and SOT patients, NoV frequently resulted in severe symptoms, prolonged diarrhea (30% persistent with diarrhea for >30 days), and clinically significant renal dysfunction (up to 21% of patients). Utilized therapies did not reliably result in the resolution of infection demonstrating the need for more effective treatment.

Modeling Invasive Aspergillosis Risk for the Application of Prophylaxis Strategies.

The epidemiology of invasive aspergillosis (IA) is evolving. To define the patient groups who will most likely benefit from primary or secondary Aspergillus prophylaxis, particularly those whose medical conditions and IA risk change over time, it is helpful to depict patient populations and their risk periods in a temporal visual model. The Sankey approach provides a dynamic figure to understand the risk of IA for various patient populations. While the figure depicted within this article is static, an internet-based version could provide pop-up highlights of any given flow's origin and destination nodes. A future version could highlight links to publications that support the color-coded incidence rates or other actionable items, such as bundles of applicable pharmacologic or non-pharmacologic interventions. The figure, as part of the upcoming Infectious Diseases Society of America's aspergillosis clinical practice guidelines, can guide decision-making in clinical settings.

How do I manage refractory invasive pulmonary aspergillosis.

BACKGROUND: Invasive aspergillosis is associated with significant morbidity and mortality in patients with haematologic malignancies and haematopoietic cell transplant recipients. The prognosis is worse among patients who have failed primary antifungal treatment. OBJECTIVES: We aim to provide guidance on the diagnosis and management of refractory invasive pulmonary aspergillosis. SOURCES: Using PubMed, we performed a review of original articles, meta-analyses, and systematic reviews. CONTENT: We discuss the diagnostic criteria for invasive pulmonary aspergillosis and the evidence on the treatment of primary infection. We outline our diagnostic approach to refractory disease. We propose a treatment algorithm for refractory disease and discuss the role of experimental antifungal agents. IMPLICATIONS: For patients with worsening disease while on antifungal therapy, a thorough diagnostic evaluation is required to confirm the diagnosis of aspergillosis and exclude another concomitant infection. Treatment should be individualized. Current options include switching to another triazole, transitioning to a lipid formulation of amphotericin B, or using combination antifungal therapy.

Stewardship-Guided T2Candida Testing Shortens Time to Antifungal Treatment and Reduces Antifungal Usage Among Medical Intensive Care Unit Patients With Septic Shock.

Background: Diagnosis of invasive candidiasis (IC) is limited by insensitivity and slow turnaround of cultures. Our objectives were to define the performance of T2Candida, a nonculture test, under guidance of a diagnostic stewardship program, and evaluate impact on time to antifungal initiation and antifungal utilization. Methods: This was a retrospective study of adult medical intensive care unit (MICU) patients with septic shock for whom T2Candida testing was performed from March 2017 to March 2020. Patients with positive T2Candida results during this period were compared to MICU patients who did not undergo T2Candida testing but had septic shock and blood cultures positive for Candida from January 2016 through March 2020. Results: Overall, 155 T2Candida tests from 143 patients were included. Nine percent of T2Candida tests were positive compared to 4.5% of blood cultures. Sensitivity, specificity, positive predictive value, and negative predictive value of T2Candida for proven and probable IC were 78%, 95%, 50%, and 99%, respectively. Patients who tested positive for T2Candida (n = 14) were diagnosed earlier and initiated on antifungal therapy sooner than patients with IC (n = 14) diagnosed by blood culture alone (median, 5.6 vs 60 hours; P < .0001). Median antifungal days of therapy/1000 patient-days were 23.3/month preimplementation and 15/month postimplementation (P  = .007). Following a negative T2Candida result, empiric antifungals were either not administered in 58% or discontinued within 72 hours in 96% of patients. Conclusions: Diagnostic stewardship guided T2Candida testing resulted in reduced time to IC diagnosis, faster initiation of antifungal therapy, and lower antifungal usage among MICU patients with septic shock.

A conceptual framework for nomenclatural stability and validity of medically important fungi: a proposed global consensus guideline for fungal name changes supported by ABP, ASM, CLSI, ECMM, ESCMID-EFISG, EUCAST-AFST, FDLC, IDSA, ISHAM, MMSA, and MSGERC.

The rapid pace of name changes of medically important fungi is creating challenges for clinical laboratories and clinicians involved in patient care. We describe two sources of name change which have different drivers, at the species versus the genus level. Some suggestions are made here to reduce the number of name changes. We urge taxonomists to provide diagnostic markers of taxonomic novelties. Given the instability of phylogenetic trees due to variable taxon sampling, we advocate to maintain genera at the largest possible size. Reporting of identified species in complexes or series should where possible comprise both the name of the overarching species and that of the molecular sibling, often cryptic species. Because the use of different names for the same species will be unavoidable for many years to come, an open access online database of the names of all medically important fungi, with proper nomenclatural designation and synonymy, is essential. We further recommend that while taxonomic discovery continues, the adaptation of new name changes by clinical laboratories and clinicians be reviewed routinely by a standing committee for validation and stability over time, with reference to an open access database, wherein reasons for changes are listed in a transparent way.

Genotypic diversity and unrecognized antifungal resistance among populations of Candida glabrata from positive blood cultures.

The longstanding model is that most bloodstream infections (BSIs) are caused by a single organism. We perform whole genome sequencing of five-to-ten strains from blood culture (BC) bottles in each of ten patients with Candida glabrata BSI. We demonstrate that BCs contain mixed populations of clonal but genetically diverse strains. Genetically distinct strains from two patients exhibit phenotypes that are potentially important during BSIs, including differences in susceptibility to antifungal agents and phagocytosis. In both patients, the clinical microbiology lab recovered a fluconazole-susceptible index strain, but we identify mixed fluconazole-susceptible and -resistant populations. Diversity in drug susceptibility is likely clinically relevant, as fluconazole-resistant strains were subsequently recovered by the clinical laboratory during persistent or relapsing infections. In one patient, unrecognized respiration-deficient small colony variants are fluconazole-resistant and significantly attenuated for virulence during murine candidiasis. Our data suggest a population-based model of C. glabrata genotypic and phenotypic diversity during BSIs.

Real-world Use of Mold-Active Triazole Prophylaxis in the Prevention of Invasive Fungal Diseases: Results From a Subgroup Analysis of a Multicenter National Registry.

Background: Antifungal prophylaxis can prevent invasive fungal diseases (IFDs) in high-risk, immunocompromised patients. This study assessed the real-world use of mold-active triazoles (MATs) for the prevention of IFDs. Methods: This subgroup analysis of a multicenter, observational, prospective registry in the United States from March 2017 to April 2020 included patients who received MATs for prophylaxis (isavuconazole, posaconazole, and voriconazole) at study index/enrollment. The primary objective was to describe patient characteristics and patterns of MAT use. Exploratory assessments included the frequency of breakthrough IFDs and MAT-related adverse drug reactions (ADRs). Results: A total of 1177 patients (256 isavuconazole, 397 posaconazole, 272 voriconazole, and 252 multiple/sequenced MATs at/after index/enrollment) were included in the prophylaxis subgroup analysis. Patient characteristics were similar across MAT groups, but risk factors varied. Hematological malignancy predominated (76.5%) across all groups. Breakthrough IFDs occurred in 7.1% (73/1030) of patients with an investigator's assessment (5.0% [11/221] isavuconazole; 5.3% [20/374] posaconazole; 4.0% [9/226] voriconazole; and 15.8% [33/209] multiple/sequenced MATs). Aspergillus (29.5% [18/61]) and Candida (36.1% [22/61]) species were the most common breakthrough pathogens recovered. ADRs were reported in 14.1% of patients, and discontinuation of MATs due to ADRs was reported in 11.1% of patients (2.0% [5/245] isavuconazole; 8.2% [30/368] posaconazole; and 10.1% [27/267] voriconazole). Conclusions: Breakthrough IFDs were uncommon in patients who received MATs for prophylaxis. Candida and Aspergillus species were the most commonly reported breakthrough pathogens. The discontinuation of MATs due to ADRs was infrequent. These findings support prophylactic strategies with isavuconazole, posaconazole, and voriconazole in high-risk patients.

Clinical and Bacterial Characteristics Associated with Glove and Gown Contamination by Carbapenem-Resistant Klebsiella pneumoniae in the Health Care Setting.

Carbapenem-resistant Klebsiella pneumoniae (CRKp) is a pathogen of significant concern to public health, as it has become increasingly associated with difficult-to-treat community-acquired and hospital-associated infections. Transmission of K. pneumoniae between patients through interactions with shared health care personnel (HCP) has been described as a source of infection in health care settings. However, it is not known whether specific lineages or isolates of K. pneumoniae are associated with increased transmission. Thus, we used whole-genome sequencing to analyze the genetic diversity of 166 carbapenem-resistant K. pneumoniae isolates from five U.S. hospitals in four states as part of a multicenter study examining risk factors for glove and gown contamination by carbapenem-resistant Enterobacterales (CRE). The CRKp isolates exhibited considerable genomic diversity with 58 multilocus sequence types (STs), including four newly designated STs. ST258 was the most prevalent ST, representing 31% (52/166) of the CRKp isolates, but was similarly prevalent among patients who had high, intermediate, and low CRKp transmission. Increased transmission was associated with clinical characteristics including a nasogastric (NG) tube or an endotracheal tube or tracheostomy (ETT/Trach). Overall, our findings provide important insight into the diversity of CRKp associated with transmission from patients to the gloves and gowns of HCP. These findings suggest that certain clinical characteristics and the presence of CRKp in the respiratory tract, rather than specific lineages or genetic content, are more often associated with increased transmission of CRKp from patients to HCP. IMPORTANCE Carbapenem-resistant Klebsiella pneumoniae (CRKp) is a significant public health concern that has contributed to the spread of carbapenem resistance and has been linked to high morbidity and mortality. Transmission of K. pneumoniae among patients through interactions with shared health care personnel (HCP) has been described as a source of infection in health care settings; however, it remains unknown whether particular bacterial characteristics are associated with increased CRKp transmission. Using comparative genomics, we demonstrate that CRKp isolates associated with high or intermediate transmission exhibit considerable genomic diversity, and there were no K. pneumoniae lineages or genes that were universally predictive of increased transmission. Our findings suggest that certain clinical characteristics and the presence of CRKp, rather than specific lineages or genetic content of CRKp, are more often associated with increased transmission of CRKp from patients to HCP.

Potential role of broad-spectrum azoles as therapy for Malasezzia bloodstream infection.

Amphotericin B is the currently recommended therapy for Malassezia invasive infection (MII), but this drug requires intravenous administration and is associated with significant toxicity. The role of broad-spectrum azoles in managing MII is not clear. We describe two cases of MII due to M. pachydermatis and M. furfur that were successfully treated with posaconazole and reviewed the literature to assess the position of posaconazole in treating MII.

Genotypic diversity and unrecognized antifungal resistance among populations of Candida glabrata from positive blood cultures.

The longstanding paradigm is that most bloodstream infections (BSIs) are caused by a single organism. We performed whole genome sequencing of five-to-ten strains from blood culture (BC) bottles in each of ten patients with Candida glabrata BSI. We demonstrated that BCs contained mixed populations of clonal but genetically diverse strains. Genetically distinct strains from two patients exhibited phenotypes that were potentially important during BSIs, including differences in susceptibility to antifungal agents and phagocytosis. In both patients, the clinical microbiology lab recovered a fluconazole-susceptible index strain, but we identified mixed fluconazole-susceptible and â€"resistant populations. Diversity in drug susceptibility was likely clinically relevant, as fluconazole-resistant strains were subsequently recovered by the clinical laboratory during persistent or relapsing infections. In one patient, unrecognized respiration-deficient small colony variants were fluconazole-resistant and significantly attenuated for virulence during murine candidiasis. Our data suggest a new population-based paradigm of C. glabrata genotypic and phenotypic diversity during BSIs.

Evaluation of fidaxomicin use in community hospitals after a clinical guideline change at a large health system and opportunities for stewardship.

After updating our health system's Clostridioides difficile treatment protocols in 2018, we reviewed 104 unique hospital encounters involving fidaxomicin at 10 community hospitals. Half (50%) of regimens were adherent to our guidelines, with infectious diseases (ID) providers were frequently nonadherent. Antimicrobial stewardship programs are important for facilitating best practices, even among ID specialists.

Within-Host Genotypic and Phenotypic Diversity of Contemporaneous Carbapenem-Resistant Klebsiella pneumoniae from Blood Cultures of Patients with Bacteremia.

It is unknown whether bacterial bloodstream infections (BSIs) are commonly caused by single organisms or mixed microbial populations. We hypothesized that contemporaneous carbapenem-resistant Klebsiella pneumoniae (CRKP) strains from blood cultures of individual patients are genetically and phenotypically distinct. We determined short-read whole-genome sequences of 10 sequence type 258 (ST258) CRKP strains from blood cultures in each of 6 patients (Illumina HiSeq). Strains clustered by patient by core genome and pan-genome phylogeny. In 5 patients, there was within-host strain diversity by gene mutations, presence/absence of antibiotic resistance or virulence genes, and/or plasmid content. Accessory gene phylogeny revealed strain diversity in all 6 patients. Strains from 3 patients underwent long-read sequencing for genome completion (Oxford Nanopore) and phenotypic testing. Genetically distinct strains within individuals exhibited significant differences in carbapenem and other antibiotic responses, capsular polysaccharide (CPS) production, mucoviscosity, and/or serum killing. In 2 patients, strains differed significantly in virulence during mouse BSIs. Genetic or phenotypic diversity was not observed among strains recovered from blood culture bottles seeded with index strains from the 3 patients and incubated in vitro at 37°C. In conclusion, we identified genotypic and phenotypic variant ST258 CRKP strains from blood cultures of individual patients with BSIs, which were not detected by the clinical laboratory or in seeded blood cultures. The data suggest a new paradigm of CRKP population diversity during BSIs, at least in some patients. If validated for BSIs caused by other bacteria, within-host microbial diversity may have implications for medical, microbiology, and infection prevention practices and for understanding antibiotic resistance and pathogenesis. IMPORTANCE The long-standing paradigm for pathogenesis of bacteremia is that, in most cases, a single organism passes through a bottleneck and establishes itself in the bloodstream (single-organism hypothesis). In keeping with this paradigm, standard practice in processing positive microbiologic cultures is to test single bacterial strains from morphologically distinct colonies. This study is the first genome-wide analysis of within-host diversity of Klebsiella pneumoniae strains recovered from individual patients with bloodstream infections (BSIs). Our finding that positive blood cultures comprised genetically and phenotypically heterogeneous carbapenem-resistant K. pneumoniae strains challenges the single-organism hypothesis and suggests that at least some BSIs are caused by mixed bacterial populations that are unrecognized by the clinical laboratory. The data support a model of pathogenesis in which pressures in vivo select for strain variants with particular antibiotic resistance or virulence attributes and raise questions about laboratory protocols and treatment decisions directed against single strains.

Development of a Centralized Antimicrobial Stewardship Program Across a Diverse Health System and Early Antimicrobial Usage Trends.

Background: Expanding antimicrobial stewardship to community hospitals is vital and now required by regulatory agencies. UPMC instituted the Centralized Health system Antimicrobial Stewardship Efforts (CHASE) Program to expand antimicrobial stewardship to all UPMC hospitals regardless of local resources. For hospitals with few local stewardship resources, we used a model integrating local non-Infectious Diseases (ID) trained pharmacists with centralized ID experts. Methods: Thirteen hospitals were included. Eleven were classified as robust (4) or nonrobust (7) depending on local stewardship resources and fulfillment of Centers for Disease Control and Prevention core elements of hospital antimicrobial stewardship. In addition to general stewardship oversight at all UPMC hospitals, the centralized team interacted regularly with nonrobust hospitals for individual patient reviews and local projects. We compared inpatient antimicrobial usage rates at nonrobust versus robust hospitals and at 2 UPMC academic medical centers. Results: The CHASE Program expanded in scope between 2018 and 2020. During this period, antimicrobial usage at these 13 hospitals decreased by 16% with a monthly change of -4.7 days of therapy (DOT)/1000 patient days (PD) (95% confidence interval [CI], -5.5 to -3.9; P < .0001). Monthly decrease at nonrobust hospitals was -3.3 DOT/1000 PD per month (-4.5 to -2.0, P < .0001), similar to rates of decline at both robust hospitals (-3.3 DOT/1000 PD) and academic medical centers (-4.8 DOT/1000 PD) (P = .167). Conclusions: Coordinated antimicrobial stewardship can be implemented across a large and diverse health system. Our hybrid model incorporating a central team of experts with local community hospital pharmacists led to usage decreases over 3 years at a rate comparable to that seen in larger hospitals with more established stewardship programs.

Noninvasive Testing and Surrogate Markers in Invasive Fungal Diseases.

Invasive fungal infections continue to increase as at-risk populations expand. The high associated morbidity and mortality with fungal diseases mandate the continued investigation of novel antifungal agents and diagnostic strategies that include surrogate biomarkers. Biologic markers of disease are useful prognostic indicators during clinical care, and their use in place of traditional survival end points may allow for more rapid conduct of clinical trials requiring fewer participants, decreased trial expense, and limited need for long-term follow-up. A number of fungal biomarkers have been developed and extensively evaluated in prospective clinical trials and small series. We examine the evidence for these surrogate biomarkers in this review and provide recommendations for clinicians and regulatory authorities.

Coronavirus Disease 2019-Associated Pulmonary Aspergillosis: Reframing the Debate.

Background: Coronavirus disease 2019 (COVID-19)-associated pulmonary aspergillosis (CAPA) has been reported in ~5%-10% of critically ill COVID-19 patients. However, incidence varies widely (0%-33%) across hospitals, most cases are unproven, and CAPA definitions and clinical relevance are debated. Methods: We reframed the debate by asking, what is the likelihood that patients with CAPA have invasive aspergillosis? We use diagnostic test performance in other clinical settings to estimate positive predictive values (PPVs) and negative predictive values (NPVs) of CAPA criteria for invasive aspergillosis in populations with varying CAPA incidence. Results: In a population with CAPA incidence of 10%, anticipated PPV/NPV of diagnostic criteria are ~30%-60%/≥97%; ~3%-5% of tested cohort would be anticipated to have true invasive aspergillosis. If CAPA incidence is 2%-3%, anticipated PPV and NPV are ~8%-30%/>99%. Conclusions: Depending on local epidemiology and clinical details of a given case, PPVs and NPVs may be useful in guiding antifungal therapy. We incorporate this model into a stepwise strategy for diagnosing and managing CAPA.

Different Conformations Revealed by NMR Underlie Resistance to Ceftazidime/Avibactam and Susceptibility to Meropenem and Imipenem among D179Y Variants of KPC ß-Lactamase.

ß-Lactamase-mediated resistance to ceftazidime-avibactam (CZA) is a serious limitation in the treatment of Gram-negative bacteria harboring Klebsiella pneumoniae carbapenemase (KPC). Herein, the basis of susceptibility to carbapenems and resistance to ceftazidime (CAZ) and CZA of the D179Y variant of KPC-2 and -3 was explored. First, we determined that resistance to CZA in a laboratory strain of Escherichia coli DH10B was not due to increased expression levels of the variant enzymes, as demonstrated by reverse transcription PCR (RT-PCR). Using timed mass spectrometry, the D179Y variant formed prolonged acyl-enzyme complexes with imipenem (IMI) and meropenem (MEM) in KPC-2 and KPC-3, which could be detected up to 24 h, suggesting that IMI and MEM act as covalent ß-lactamase inhibitors more than as substrates for D179Y KPC-2 and -3. This prolonged acyl-enzyme complex of IMI and MEM by D179Y variants was not observed with wild-type (WT) KPCs. CAZ was studied and the D179Y variants also formed acyl-enzyme complexes (1 to 2 h). Thermal denaturation and differential scanning fluorimetry showed that the tyrosine substitution at position 179 destabilized the KPC ß-lactamases (KPC-2/3 melting temperature [Tm] of 54 to 55°C versus D179Y Tm of 47.5 to 51°C), and the D179Y protein was 3% disordered compared to KPC-2 at 318 K. Heteronuclear 1H/15N-heteronuclear single quantum coherence (HSQC) nuclear magnetic resonance (NMR) spectroscopy also revealed that the D179Y variant, compared to KPC-2, is partially disordered. Based upon these observations, we discuss the impact of disordering of the Ω loop as a consequence of the D179Y substitution. These conformational changes and disorder in the overall structure as a result of D179Y contribute to this unanticipated phenotype.

Candidemia Among Coronavirus Disease 2019 Patients in Turkey Admitted to Intensive Care Units: A Retrospective Multicenter Study.

Background: We evaluated the epidemiology of candidemia among coronavirus disease 2019 (COVID-19) patients admitted to intensive care units (ICUs). Methods: We conducted a retrospective multicenter study in Turkey between April and December 2020. Results: Twenty-eight of 148 enrolled patients developed candidemia, yielding an incidence of 19% and incidence rate of 14/1000 patient-days. The probability of acquiring candidemia at 10, 20, and 30 days of ICU admission was 6%, 26%, and 50%, respectively. More than 80% of patients received antibiotics, corticosteroid, and mechanical ventilation. Receipt of a carbapenem (odds ratio [OR] = 6.0, 95% confidence interval [CI] = 1.6-22.3, P = .008), central venous catheter (OR = 4.3, 95% CI = 1.3-14.2, P = .02), and bacteremia preceding candidemia (OR = 6.6, 95% CI = 2.1-20.1, P = .001) were independent risk factors for candidemia. The mortality rate did not differ between patients with and without candidemia. Age (OR = 1.05, 95% CI = 1.01-1.09, P = .02) and mechanical ventilation (OR = 61, 95% CI = 15.8-234.9, P < .0001) were independent risk factors for death. Candida albicans was the most prevalent species overall. In Izmir, Candida parapsilosis accounted for 50% (2 of 4) of candidemia. Both C parapsilosis isolates were fluconazole nonsusceptible, harbored Erg11-Y132F mutation, and were clonal based on whole-genome sequencing. The 2 infected patients resided in ICUs with ongoing outbreaks due to fluconazole-resistant C parapsilosis. Conclusions: Physicians should be aware of the elevated risk for candidemia among patients with COVID-19 who require ICU care. Prolonged ICU exposure and ICU practices rendered to COVID-19 patients are important contributing factors to candidemia. Emphasis should be placed on (1) heightened infection control in the ICU and (2) developing antibiotic stewardship strategies to reduce irrational antimicrobial therapy.

Screening for Ocular Candidiasis Among Patients With Candidemia: Is It Time to Change Practice?

Ocular candidiasis (OC) complicates approximately 10% of candidemia and carries potentially severe morbidity. There are conflicting recommendations about the need for routine funduscopic examinations of candidemic patients. Indirect funduscopy is accurate and safe in diagnosing OC, and positive findings change recommended treatment. However, conclusive evidence that treatment changes improve outcomes is lacking. Bringing perspectives as infectious diseases physicians and ophthalmologists, we review controversies about OC and endorse routine screening during candidemia. We acknowledge difficulties in obtaining inpatient ophthalmologic consults and recommend studies to evaluate digital fundus photography and teleophthalmology as an alternative to funduscopic examinations by ophthalmologists in asymptomatic patients.