Direct evidence for phosphorus limitation on Amazon forest productivity.

The productivity of rainforests growing on highly weathered tropical soils is expected to be limited by phosphorus availability1. Yet, controlled fertilization experiments have been unable to demonstrate a dominant role for phosphorus in controlling tropical forest net primary productivity. Recent syntheses have demonstrated that responses to nitrogen addition are as large as to phosphorus2, and adaptations to low phosphorus availability appear to enable net primary productivity to be maintained across major soil phosphorus gradients3. Thus, the extent to which phosphorus availability limits tropical forest productivity is highly uncertain. The majority of the Amazonia, however, is characterized by soils that are more depleted in phosphorus than those in which most tropical fertilization experiments have taken place2. Thus, we established a phosphorus, nitrogen and base cation addition experiment in an old growth Amazon rainforest, with a low soil phosphorus content that is representative of approximately 60% of the Amazon basin. Here we show that net primary productivity increased exclusively with phosphorus addition. After 2 years, strong responses were observed in fine root (+29%) and canopy productivity (+19%), but not stem growth. The direct evidence of phosphorus limitation of net primary productivity suggests that phosphorus availability may restrict Amazon forest responses to CO2 fertilization4, with major implications for future carbon sequestration and forest resilience to climate change.

MicroRNAs in infectious diseases: potential diagnostic biomarkers and therapeutic targets.

MicroRNAs (miRNAs) are conserved, short, non-coding RNAs that play a crucial role in the post-transcriptional regulation of gene expression. They have been implicated in the pathogenesis of cancer and neurological, cardiovascular, and autoimmune diseases. Several recent studies have suggested that miRNAs are key players in regulating the differentiation, maturation, and activation of immune cells, thereby influencing the host immune response to infection. The resultant upregulation or downregulation of miRNAs from infection influences the protein expression of genes responsible for the immune response and can determine the risk of disease progression. Recently, miRNAs have been explored as diagnostic biomarkers and therapeutic targets in various infectious diseases. This review summarizes our current understanding of the role of miRNAs during viral, fungal, bacterial, and parasitic infections from a clinical perspective, including critical functional mechanisms and implications for their potential use as biomarkers and therapeutic targets.

Giants of the Amazon: How does environmental variation drive the diversity patterns of large trees?

For more than three decades, major efforts in sampling and analyzing tree diversity in South America have focused almost exclusively on trees with stems of at least 10 and 2.5 cm diameter, showing highest species diversity in the wetter western and northern Amazon forests. By contrast, little attention has been paid to patterns and drivers of diversity in the largest canopy and emergent trees, which is surprising given these have dominant ecological functions. Here, we use a machine learning approach to quantify the importance of environmental factors and apply it to generate spatial predictions of the species diversity of all trees (dbh ≥ 10 cm) and for very large trees (dbh ≥ 70 cm) using data from 243 forest plots (108,450 trees and 2832 species) distributed across different forest types and biogeographic regions of the Brazilian Amazon. The diversity of large trees and of all trees was significantly associated with three environmental factors, but in contrasting ways across regions and forest types. Environmental variables associated with disturbances, for example, the lightning flash rate and wind speed, as well as the fraction of photosynthetically active radiation, tend to govern the diversity of large trees. Upland rainforests in the Guiana Shield and Roraima regions had a high diversity of large trees. By contrast, variables associated with resources tend to govern tree diversity in general. Places such as the province of Imeri and the northern portion of the province of Madeira stand out for their high diversity of species in general. Climatic and topographic stability and functional adaptation mechanisms promote ideal conditions for species diversity. Finally, we mapped general patterns of tree species diversity in the Brazilian Amazon, which differ substantially depending on size class.

Progression of human monkeypox infection despite tecovirimat in an immunocompromised adult.

We report a case of an immunocompromised man with monkeypox who experienced disease progression despite timely initiation of tecovirimat and ultimately required utilization of cidofovir and VIGIV for treatment. In immunocompromised patients, monkeypox might present with a more severe course of disease requiring consideration of alternative treatment strategies.

Successful restoration of protective immunity against measles, mumps, and rubella following MMR vaccination in adult hematopoietic cell transplant recipients.

BACKGROUND: The optimal number of doses as well as the role for measurement of postvaccination titers after measles, mumps, rubella (MMR) vaccination in adult hematopoietic cell transplantation (HCT) recipients remains unknown. METHODS: In the present study, we assessed humoral immunity against measles, mumps and rubella before and after MMR vaccination in 187 adults who received at least one dose of the MMR vaccine after HCT. RESULTS: Among those with baseline titers, posttransplant prevaccination seroprotection rates were 56%, 30%, and 54% for measles, mumps, and rubella, respectively; and significantly lower in allogeneic versus autologous HCT recipients for measles (39% vs. 80%, p = .0001), mumps (22% vs. 41%; p = .02) and rubella (48% vs. 62%, p = .12). Among those who were seronegative at baseline, seroconversion rates after one dose of MMR were 69%, 56%, and 97% for measles, mumps, and rubella, respectively. Seronegative patients after one dose of MMR (i.e., nonresponders) seroconverted for measles and mumps after a second MMR vaccine dose. CONCLUSION: Our findings demonstrate successful restoration of protective immunity against measles, mumps, and rubella after vaccination in adult HCT recipients; one dose of MMR elicited protective titers in the majority of patients, and a second vaccine dose was immunogenic in nonresponders.

Early administration of SARS-CoV-2 monoclonal antibody reduces the risk of mortality in hematologic malignancy and hematopoietic cell transplant patients with COVID-19.

BACKGROUND: Data on severe acute respiratory distress syndrome coronavirus 2 monoclonal antibody (SARS-CoV-2-specific mAb) use in hematologic malignancy and hematopoietic cell transplantation (HM/HCT) patients are limited. Here, we describe our experience with the use of casirivimab-imdevimab or bamlanivimab for the treatment of coronavirus disease 2019 (COVID-19) in HM/HCT patients. METHODS: This was a retrospective chart review at the University of Miami Hospital and Sylvester Comprehensive Cancer Center for HM/HCT patients with COVID-19 who received casirivimab-imdevimab or bamlanivimab from November 21, 2020, to September 30, 2021. Outcomes measured were mortality, hospital admission, and infusion reaction to SARS-CoV-2-specific mAbs. RESULTS: We identified 59 HM/HCT patients with mild to moderate COVID-19 who received casirivimab-imdevimab or bamlanivimab. Median age was 57 years (interquartile range [IQR]: 45-65). Among the 59 patients, 25 (42%) received cellular therapy: 14 (24%) had undergone allogeneic HCT, nine (15%) autologous HCT, and two (3%) received chimeric antigen receptor T-cell therapy. The median time from COVID-19 symptom onset to SARS-CoV-2-specific mAb administration was 4 (IQR: 3-6) days. Forty-six (78%) patients received SARS-CoV-2-specific mAbs as outpatients and 13 (22%) patients received SARS-CoV-2-specific mAbs during hospitalization. Among patients who received SARS-CoV-2-specific mAbs as outpatients, only four (9%) visited the emergency department at days 10, 11, 15, and 35 after SARS-CoV-2-specific mAb administration. None of these four patients required hospital admission. Among the hospitalized patients, five (38%) were admitted to the hospital with neutropenic fever, four (31%) were already hospitalized for transplantation and cellular therapy, three (23%) were admitted for monitoring of COVID-19 symptoms, and one (8%) was admitted with acute kidney injury. Three hospitalized patients (23%) died at 14, 35, and 59 days after SARS-CoV-2-specific mAb administration; two of these three deaths were attributed to COVID-19 infection. One patient developed an immediate infusion reaction to bamlanivimab, and no infusion reactions were reported to casirivimab-imdevimab use. CONCLUSION: During the alpha and delta variant surges, early administration of bamlanivimab or casirivimab-imdevimab prevented hospitalization and death when given in the outpatient setting. Among patients who received mAbs at or after hospital admission, the risk of COVID-19 disease progression and death remains significant. Larger studies of the use of mAb therapy to treat COVID-19 in this population are needed.

Breakthrough invasive fungal infections on isavuconazole prophylaxis in hematologic malignancy & hematopoietic stem cell transplant patients.

BACKGROUND: Isavuconazole (ISA) is a newer antifungal used in patients with history of hematologic malignancies and hematopoietic transplant and cellular therapies (HM/TCT). Although it has a more favorable side-effect profile, breakthrough invasive fungal infections (bIFIs) while on ISA have been reported. METHODS: In this single-center retrospective study evaluating HM/TCT patients who received prophylactic ISA for ≥7 days, we evaluated the incidence and potential risk factors for bIFIs. RESULTS: We evaluated 106 patients who received prophylactic ISA. The patients were predominantly male (60.4%) with median age of 65 (range: 21-91) years. Acute myeloid leukemia (48/106, 45.3%) was the most common HM, with majority having relapsed and/or refractory disease (43/106, 40.6%) or receiving ongoing therapy (38/106, 35.8%). Nineteen patients (17.9%) developed bIFIs-nine proven [Fusarium (3), Candida (2), Mucorales plus Aspergillus (2), Mucorales (1), Colletotrichum (1)], four probable invasive pulmonary Aspergillus, and six possible infections. Twelve patients were neutropenic for a median of 28 (8-253) days prior to bIFI diagnosis. ISA levels checked within 7 days of bIFI diagnosis (median: 3.65 µg/mL) were comparable to industry-sponsored clinical trials. All-cause mortality among the bIFI cases was 47.4% (9/19).We also noted clinically significant cytomegalovirus co-infection in 5.3% (1/19). On univariate analysis, there were no significant differences in baseline comorbidities and potential risk factors between the two groups. CONCLUSION: ISA prophylaxis was associated with a significant cumulative incidence of bIFIs. Despite the appealing side-effect and drug-interaction profile of ISA, clinicians must be vigilant about the potential risk for bIFIs.

Successful Treatment of Disseminated Disease Due to Highly Resistant Aspergillus calidoustus with a Novel Antifungal Therapy.

Invasive aspergillosis is the most common invasive mold infection following a hematopoietic cell transplant. Widespread use of antifungal prophylaxis has led to the increasing incidence of cryptic Aspergillus species. Aspergillus calidoustus is one of those emerging species and is notorious for multidrug resistance to antifungals. Here, we report a case of disseminated A. calidoustus infection in a hematopoietic stem cell transplant recipient who was successfully treated with combination therapy that included a novel antifungal.

Rapid responses of root traits and productivity to phosphorus and cation additions in a tropical lowland forest in Amazonia.

Soil nutrient availability can strongly affect root traits. In tropical forests, phosphorus (P) is often considered the main limiting nutrient for plants. However, support for the P paradigm is limited, and N and cations might also control tropical forests functioning. We used a large-scale experiment to determine how the factorial addition of nitrogen (N), P and cations affected root productivity and traits related to nutrient acquisition strategies (morphological traits, phosphatase activity, arbuscular mycorrhizal colonisation and nutrient contents) in a primary rainforest growing on low-fertility soils in Central Amazonia after 1 yr of fertilisation. Multiple root traits and productivity were affected. Phosphorus additions increased annual root productivity and root diameter, but decreased root phosphatase activity. Cation additions increased root productivity at certain times of year, also increasing root diameter and mycorrhizal colonisation. P and cation additions increased their element concentrations in root tissues. No responses were detected with N addition. Here we showed that rock-derived nutrients determined root functioning in low-fertility Amazonian soils, demonstrating not only the hypothesised importance of P, but also highlighting the role of cations. The changes in fine root traits and productivity indicated that even slow-growing tropical rainforests can respond rapidly to changes in resource availability.

Lack of correlation between the SARS-CoV-2 cycle threshold (Ct ) value and clinical outcomes in patients with COVID-19.

PROBLEM: The utility of the polymerase chain reaction (PCR) cycle threshold (Ct ) values in the management of patients with coronavirus disease 2019 (COVID-19) remains controversial. METHODS: We assessed the correlation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Ct values in nasopharyngeal swab samples with the oxygen requirements at the time of sample collection. Specimens were tested with the Simplexa PCR platform, which targets the SARS-CoV-2 ORF1ab and S genes. RESULTS: We identified 23 COVID-19 patients with 49 Ct values available. While Ct values from ORF1ab and S genes were highly correlated for a given specimen, there was no correlation between Ct values for any of these target genes and the oxygen requirements of the patient at the time of sample collection. We found no differences in the initial nor the nadir Ct values between survivors and non-survivors or mild/moderate versus severe/critical illness at the maximum point of illness. CONCLUSION: SARS-CoV-2 Ct values have limited value in the management of COVID-19.

Deep functional immunophenotyping predicts risk of cytomegalovirus reactivation after hematopoietic cell transplantation.

Cytomegalovirus (CMV) is the most common viral infection in hematopoietic cell transplantation (HCT) recipients. We performed deep phenotyping of CMV-specific T cells to predict CMV outcomes following allogeneic HCT. By using 13-color flow cytometry, we studied ex vivo CD8+ T-cell cytokine production in response to CMV-pp65 peptides in 3 clinically distinct subgroups of CMV-seropositive HCT patients: (1) Elite Controllers (n = 19): did not have evidence of CMV DNAemia on surveillance testing; (2) Spontaneous Controllers (n = 16): spontaneously resolved low-grade CMV DNAemia without antiviral therapy; and (3) Noncontrollers (NC; n = 21): experienced clinically significant CMV. Two CMV-specific CD8+ T-cell functional subsets were strongly associated with risk of CMV: (i) the nonprotective signature (NPS; IL-2-IFN-γ+TNF-α-MIP-1ß+), found at increased levels among NC; and (ii) the protective signature (PS; IL-2+IFN-γ+TNF-α+MIP-1ß+) found at low levels among NC. High levels of the NPS and low levels of PS were associated with an increased 100-day cumulative incidence of clinically significant CMV infection (35% vs 5%; P = .02; and 40% vs 12%; P = .05, respectively). The highest predictive value was observed when these signatures were combined into a composite biomarker consisting of low levels of the PS and high levels of the NPS (67% vs 10%; P < .001). After adjusting for steroid use or donor type, this composite biomarker remained associated with a fivefold increase in the risk of clinically significant CMV infection. CMV-specific CD8+ T-cell cytokine signatures with robust predictive value for risk of CMV reactivation should prove useful in guiding clinical decision making in HCT recipients.

Viral kinetics and outcomes of adenovirus viremia following allogeneic hematopoietic cell transplantation.

BACKGROUND: Adenovirus (AdV) is a serious infection following hematopoietic cell transplantation (HCT). Little is known about AdV viral kinetics and optimal threshold for initiation of pre-emptive therapy. METHODS: Single-center retrospective study of 16 consecutive adult HCT recipients with detectable AdV identified over a 5-year period. RESULTS: Median time to AdV reactivation after HCT was 176 days (IQR 86-408). Nine patients received cidofovir, although 14/16 had no tissue-invasive disease. Among treated patients, median duration of viremia was shorter when initiating treatment at viral loads < 10,000 copies/ml (28 vs. 52 days). All-cause mortality in this cohort was 44%. All six patients (five of which were untreated) with peak viral loads < 10,000 copies/ml survived; whereas only 30% (3/10) of patients with peak viral loads greater than this threshold survived, despite most (n = 8; 80%) of them receiving cidofovir (P = .01). Three-month survival following diagnosis of AdV viremia was significantly lower with peak viremia > 10,000 copies/ml (100 vs. 17%; P = .005). CONCLUSION: AdV is associated with high all-cause mortality, especially for viremia > 10,000 copies/ml. Delaying therapy until viremia reaches AdV levels ≥10,000 copies/ml was associated with more protracted infection and poor outcomes. Larger studies are needed.

Clinical presentation and outcomes of COVID-19 following hematopoietic cell transplantation and cellular therapy.

BACKGROUND: One year into the pandemic, published data on hematopoietic cell transplantation (HCT) recipients with coronavirus disease 2019 (COVID-19) remain limited. METHODS: Single-center retrospective cohort study of adult HCT recipients with polymerase chain reaction (PCR)-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. RESULTS: Twenty-eight consecutive transplantation and cellular therapy patients (autologous, n = 12; allogeneic, n = 15; chimeric antigen receptor T-cell therapy [CAR-T], n = 1) with COVID-19 were identified. The median age was 57 years. The median time from HCT to COVID-19 diagnosis was 656 days (interquartile range [IQR], 33-1274). Patients were followed for a median of 59 days (IQR, 40-88). Among assessable patients (n = 19), 10 (53%) had documented virological clearance; median time to clearance was 34 days (range, 21-56). Out of 28, 12 (43%), 6 (21%), and 10 (36%) patients had mild, moderate, and severe/critical disease, respectively. Overall mortality was 25%, nearly identical for autologous and allogeneic HCT, and exclusively seen in hospitalized patients, older than 50 years of age with severe COVID-19. None of the patients with mild (n = 12) or moderate (n = 6) COVID-19 died whereas 7/10 patients (70%) with severe/critical COVID-19 died (P = .0001). Patients diagnosed with COVID-19 within 12 months of HCT exhibited higher mortality (57% vs 14%; P = .04). All-cause 30-day mortality (n = 4) was 14%. A higher proportion of patients who died within 30 days of COVID-19 diagnosis (3/4) were receiving ≥2 immunosuppressants, compared with patients who survived beyond 30 days after COVID-19 diagnosis (2/24; 75% vs. 8%; P = .01). CONCLUSIONS: Mortality in COVID-19 HCT patients is higher than that of the age-comparable general population and largely dependent on age, disease severity, timing from HCT, and intensity of immunosuppression.

Clinical "real-world" experience with letermovir for prevention of cytomegalovirus infection in allogeneic hematopoietic cell transplant recipients.

BACKGROUND: Letermovir was approved in 2017 for prevention of cytomegalovirus (CMV) infection in seropositive (R+) allogeneic hematopoietic cell transplantation (HCT) patients. Post-marketing data with this new agent are scarce. METHODS: We compared the incidence of both CMV reactivation (any viremia) and clinically significant CMV infection (CS-CMVi; CMV DNAemia leading to preemptive treatment or presence of CMV tissue invasive disease) at days +100 and +200 post-HCT in 25 adult allogeneic HCT patients who received letermovir prophylaxis (until day 100) and a historical control group of 106 CMV R+ allogeneic HCT recipients who underwent CMV preemptive therapy. RESULTS: CMV reactivation within 100 days post-HCT was lower in the letermovir group vs control group (20% vs 72% respectively, P < .001). The 100-day cumulative incidence of CS-CMVi was significantly lower in the letermovir group vs control group (4% vs 59% respectively, P < .001). Significantly reduced incidence of CMV reactivation and CS-CMVi was also observed at 200 days in the letermovir group. No difference in mortality was observed between the two groups. CONCLUSION: This study confirms the efficacy of letermovir in preventing CMV reactivation in CMV R+ allogeneic HCT recipients in first 100 days post-HCT and suggests sustained efficacy after discontinuation of prophylaxis.

Treatment of latent tuberculosis infection with short-course regimens in potential living kidney donors.

BACKGROUND: Treatment data for latent tuberculosis infection (LTBI) among potential living kidney donors are scarce. METHODS: This retrospective study was performed to evaluate the prevalence of positive QuantiFERON-TB Gold In-Tube (QFT-GIT) among potential living kidney donors that were screened from 2009 to 2017. We investigated if there was any difference in the time to donation between QFT-GIT-positive and QFT-GIT-negative donors. We assessed the regimens used to treat LTBI and whether the recipients of QFT-GIT-positive donors developed active tuberculosis (TB). RESULTS: Forty out of 427 (9%) potential living kidney donors had a positive QFT-GIT. QFT-GIT-positive donors were as likely as negative donors to undergo donation (30 [75%] vs 315 [81%], P = .33). The time from QFT-GIT testing to donation was longer among QFT-GIT-positive donors (median 221 days [range: 4-1139] vs 86 days [range: 3-1887], P = .001). Twelve-week rifapentine (RPT)/Isoniazid (INH) was the most common treatment used and was not associated with significant adverse reactions. There was a trend toward longer time to donation among QFT-GIT-positive donors who were treated for LTBI compared with QFT-GIT-positive donors who were not (252 days [range: 88-1139] vs 95 days [range: 4-802], P = .05). Twenty-nine recipients of QFT-GIT-positive living kidney donors were evaluated. Eleven of these recipients received kidneys from donors that were not treated for LTBI. Two of these recipients were treated with INH post-transplantation. CONCLUSIONS: The time from QFT-GIT testing to donation was longer among QFT-GIT-positive donors. The short-course regimens appear to be excellent options for LTBI treatment among living kidney donors and avoid delaying organ donation further.

Kidney transplantation during coronavirus 2019 pandemic at a large hospital in Miami.

BACKGROUND: Coronavirus 2019 (COVID-19) pandemic has resulted in more than 350 000 deaths worldwide. The number of kidney transplants has declined during the pandemic. We describe our deceased donor kidney transplantation (DDKT) experience during the pandemic. METHODS: A retrospective study was conducted to evaluate the safety of DDKT during the COVID-19 pandemic. Multiple preventive measures were implemented. Adult patients that underwent DDKT from 3/1/20 to 4/30/20 were included. COVID-19 clinical manifestations from donors and recipients, and post-transplant outcomes (COVID-19 infections, readmissions, allograft rejection, and mortality) were obtained. The kidney transplant (KT) recipients were followed until 5/31/20. RESULTS: Seventy-six patients received kidneys from 57 donors. Fever, dyspnea, and cough were reported in 1, 2, and 1 donor, respectively. Thirty-eight (66.6%) donors were tested for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) prior to donation (mainly by nasopharyngeal or bronchoalveolar lavage polymerase chain reaction [PCR]) and 36 (47.3%) KT recipients were tested at the time of DDKT by nasopharyngeal PCR; all of these were negative. Our recipients were followed for a median of 63 (range: 33-91) days. A total of 42 (55.3%) recipients were tested post-transplant for SARS-CoV2 by nasopharyngeal PCR including 12 patients that became symptomatic; all tests were negative except for one that was inconclusive, but it was repeated and came back negative. Forty (52.6%) KT recipients were readmitted, and 7 (9.2%) had biopsy-proven rejection during the follow-up. None of the KT recipients transplanted during this period died. CONCLUSIONS: Our cohort demonstrated that DDKT can be safely performed during the COVID-19 pandemic when preventive measures are implemented.

Antimicrobial resistance and recurrent bacterial urinary tract infections in hospitalized patients following kidney transplantation: A single-center experience.

PURPOSE: The burden of urinary tract infections (UTIs) and risk factors for developing infections with multidrug resistant organisms (MDROs) post-kidney transplantation (KT) are poorly understood. METHODS: Single-center retrospective cohort study (January 2015-December 2017) evaluating first and recurrent episodes of bacteriuria and subsequent analysis of episodes caused by MDROs up to 6 months post-KT. Donor and recipient variables were reviewed. RESULTS: A total of 743 adults underwent single KT during the study period, and 106 patients were hospitalized with bacteriuria. 45% were asymptomatic in their first episode. 73.6% had a single episode, and 26.4% had 2 or more episodes. A total of 28 patients had recurrent episodes; 64.3% had an MDRO on the first episode and 78.6% on the second episode. Escherichia coli was the most common organism isolated, 88.5% were resistant to trimethoprim-sulfamethoxazole (TMP-SMX), 9.3% were extended-spectrum beta-lactamase (ESBL) producers, and 38.1% were MDROs. Body mass index ≥30 was significantly associated with the presence of MDROs in both univariate and multivariate analyses (RR 1.37, 95% CI 1.01-1.88; OR 3.26, CI 1.29-8.25). A total of 12 donors had bacteremia or bacteriuria and 6 (50%) with E coli. A total of 10 KT recipients received antibiotic prophylaxis to prevent donor-derived infections. CONCLUSIONS: Our results suggest that a significant proportion of patients develop recurrent bacteriuria post-transplantation; of those, more than half caused by MDROs. There is a possible association between obesity and MDROs in KT recipients that merits further investigation. With the global crisis in antimicrobial resistance, innovative strategies are needed to prevent and treat UTIs in KT patients.

Successful Treatment of Invasive Fungal Infection Due to Highly Resistant Aspergillus calidoustus in an Allogeneic Hematopoietic Cell Transplant Recipient.

Invasive aspergillosis (IA) is the most common invasive fungal infection following a hematopoietic cell transplant, with emerging cryptic species exhibiting resistance to commonly used antifungals such as azoles. These species have been increasingly found after the introduction of anti-mold prophylaxis. We report a case of a 56-year-old female with primary myelofibrosis whose allogeneic hematopoietic cell transplant was complicated by disseminated fungal infection (skin, lung) due to Aspergillus calidoustus, a cryptic specie. Treatment of Aspergillus species remains challenging as these cryptic species are usually resistant to azoles including voriconazole which is the first line of treatment of IA. Infection was successfully treated with surgical excision and combination antifungal therapy based on in vitro susceptibility and synergy testing. Therapy included isavuconazole, a drug that has been shown to be non-inferior to voriconazole in the treatment of invasive mold infections.

Linezolid- and Vancomycin-resistant Enterococcus faecium in Solid Organ Transplant Recipients: Infection Control and Antimicrobial Stewardship Using Whole Genome Sequencing.

BACKGROUND: Vancomycin-resistant enterococci are an important cause of healthcare-associated infections and are inherently resistant to many commonly used antibiotics. Linezolid is the only drug currently approved by the US Food and Drug Administration to treat vancomycin-resistant enterococci; however, resistance to this antibiotic appears to be increasing. Although outbreaks of linezolid- and vancomycin-resistant Enterococcus faecium (LR-VRE) in solid organ transplant recipients remain uncommon, they represent a major challenge for infection control and hospital epidemiology. METHODS: We describe a cluster of 4 LR-VRE infections among a group of liver and multivisceral transplant recipients in a single intensive care unit. Failure of treatment with linezolid in 2 cases led to a review of standard clinical laboratory methods for susceptibility determination. Testing by alternative methods including whole genome sequencing (WGS) and a comprehensive outbreak investigation including sampling of staff members and surfaces was performed. RESULTS: Review of laboratory testing methods revealed a limitation in the VITEK 2 system with regard to reporting resistance to linezolid. Linezolid resistance in all cases was confirmed by E-test method. The use of WGS identified a resistant subpopulation with the G2376C mutation in the 23S ribosomal RNA. Sampling of staff members' dominant hands as well as sampling of surfaces in the unit identified no contaminated sources for transmission. CONCLUSIONS: This cluster of LR-VRE in transplant recipients highlights the possible shortcomings of standard microbiology laboratory methods and underscores the importance of WGS to identify resistance mechanisms that can inform patient care, as well as infection control and antibiotic stewardship measures.