Increased Incidence of Nocardial Infections in an Era of Atovaquone Prophylaxis in Allogeneic Hematopoietic Stem Cell Transplant Recipients

Risk factors for Nocardia infection among allogeneic hematopoietic cell transplant recipients: A case-control study of the Infectious Diseases Working Party of the European Society for Blood and Marrow Transplantation

OBJECTIVES

Nocardiosis is a rare but life-threatening infection after hematopoietic cell transplantation (HCT). We aimed at identifying risk factors for nocardiosis after allogeneic HCT and clarifying the effect of trimethoprim-sulfamethoxazole prophylaxis on its occurrence.

METHODS

We performed a retrospective multicenter case-control study of patients diagnosed with nocardiosis after allogeneic HCT between January 2000 and December 2018. For each case, two controls were matched by center, transplant date, and age group. Multivariable analysis was conducted using conditional logistic regression to identify potential risk factors for nocardiosis. Kaplan-Meier survival curves of cases and controls were compared using log-rank tests.

RESULTS

Sixty-four cases and 128 controls were included. Nocardiosis occurred at a median of 9 months after allogeneic HCT (interquartile range: 5-18). After adjustment for potential confounders in a multivariable model, Nocardia infection was associated with tacrolimus use (adjusted odds ratio [aOR] 9.9, 95 % confidence interval [95 % CI]: 1.6-62.7), lymphocyte count < 500/µL (aOR 8.9, 95 % CI: 2.3-34.7), male sex (aOR 8.1, 95 % CI: 2.1-31.5), recent use of systemic corticosteroids (aOR 7.9, 95 % CI: 2.2-28.2), and recent CMV infection (aOR 4.3, 95 % CI: 1.2-15.9). Conversely, use of trimethoprim-sulfamethoxazole prophylaxis was associated with a significantly decreased risk of nocardiosis (aOR 0.2, 95 % CI: 0.1-0.8). HCT recipients who developed nocardiosis had a significantly decreased survival, as compared with controls (12-month survival: 58 % and 90 %, respectively; p < 0.0001).

CONCLUSIONS

We identified six factors independently associated with the occurrence of nocardiosis among allogeneic HCT recipients. In particular, trimethoprim-sulfamethoxazole prophylaxis was found to protect against nocardiosis.

Outcomes of transplant recipients with pretransplant Nocardia colonization or infection

BACKGROUND

Specific pretransplant infections have been associated with poor posttransplant outcomes. However, the impact of pretransplant Nocardia isolation has not been studied.

METHODS

We performed a retrospective study from three centers in Arizona, Florida, and Minnesota of patients with Nocardia infection or colonization who subsequently underwent solid organ or hematopoietic stem cell transplantation from November 2011 through April 2022. Outcomes included posttransplant Nocardia infection and mortality.

RESULTS

Nine patients with pretransplant Nocardia were included. Two patients were deemed colonized with Nocardia, and the remaining seven had nocardiosis. These patients underwent bilateral lung (N = 5), heart (N = 1), heart-kidney (N = 1), liver-kidney (N = 1), and allogeneic stem cell transplantation (N = 1) at a median of 283 (interquartile range [IQR] 152-283) days after Nocardia isolation. Two (22.2%) patients had disseminated infection, and two were receiving active Nocardia treatment at the time of transplantation. One Nocardia isolate was resistant to trimethoprim-sulfamethoxazole (TMP-SMX) and all patients received TMP-SMX prophylaxis posttransplant, often for extended durations. No patients developed posttransplant nocardiosis during a median follow-up of 1.96 (IQR 0.90-6.33) years. Two patients died during follow-up, both without evidence of nocardiosis.

CONCLUSIONS

This study did not identify any episodes of posttransplant nocardiosis among nine patients with pretransplant Nocardia isolation. As patients with the most severe infections may have been denied transplantation, further studies with larger sample sizes are needed to better analyze any impact of pretransplant Nocardia on posttransplant outcomes. However, among patients who receive posttransplant TMP-SMX prophylaxis, these data suggest pretransplant Nocardia isolation may not impart a heightened risk of posttransplant nocardiosis.

Risk factors and prophylaxis for nocardiosis in solid organ transplant recipients: A nested case-control study

BACKGROUND

Nocardia is an opportunistic pathogen that primarily affects immunocompromised individuals, including solid organ transplant (SOT) recipients. Up to 2.65% of SOT recipients develop nocardiosis; however, few studies have examined risk factors and prophylaxis for nocardiosis.

METHODS

We performed a multicenter, matched nested case-control study of adult SOT recipients with culture-confirmed nocardiosis from 2000 through 2020. Controls were matched up to 2:1 by sex, first transplanted organ, year of transplant, transplant center, and adequate post-transplant follow-up. Multivariable conditional logistic regression was performed to analyze associations with nocardiosis. Cox proportional hazards regression compared 12-month mortality between infection and uninfected patients.

RESULTS

One hundred and twenty-three SOT recipients were matched to 245 uninfected controls. Elevated calcineurin inhibitor level, acute rejection, cytomegalovirus infection, lymphopenia, higher prednisone dose, and older age were significantly associated with nocardiosis while trimethoprim-sulfamethoxazole prophylaxis was protective (odds ratio [OR] .34; 95% confidence interval [CI] .13-.84). The effect of prophylaxis was similar, though not always statistically significant, in sensitivity analyses that only included prophylaxis dosed more than twice-per-week (OR .30; 95% CI .11-.80) or restricted to years 2015-2020 (OR .33, 95% CI .09-1.21). Nocardiosis was associated with increased 12-month mortality (hazard ratio 5.47; 95% confidence interval 2.42-12.35).

CONCLUSIONS

Multiple measures of immunosuppression and lack of trimethoprim-sulfamethoxazole prophylaxis were associated with nocardiosis in SOT recipients. Effectiveness of prophylaxis may be related to trimethoprim-sulfamethoxazole dose or frequency. Trimethoprim-sulfamethoxazole should be preferentially utilized over alternative agents in SOT recipients with augmented immunosuppression or signs of heightened immunocompromise.

Bacterial Pathogens Causing Pneumonia Post Hematopoietic Stem Cell Transplant: The Chronic GVHD Population

Allogeneic stem cell transplantation is a lifesaving treatment for many malignancies. Post-transplant patients may suffer from graft versus host disease in the acute and/or the chronic form(s). Post-transplantation immune deficiency due to a variety of factors is a major cause of morbidity and mortality. Furthermore, immunosuppression can lead to alterations in host factors that predisposes these patients to infections. Although patients who receive stem cell transplant are at an increased risk of opportunistic pathogens, which include fungi and viruses, bacterial infections remain the most common cause of morbidity. Here, we review bacterial pathogens that lead to pneumonias specifically in the chronic GVHD population.

Risk Factors and Outcomes of Nocardiosis in Hematopoietic Stem Cell Transplantation Recipients

Nocardiosis occurs in up to 1.7% of hematopoietic stem cell transplantation (HSCT) recipients. Risk factors for its development and subsequent outcomes have been incompletely studied. The present study evaluated risk factors for nocardiosis in HSCT recipients and an association with 12-month mortality following Nocardia infection. We performed a nested case-control study of HSCT recipients at 3 transplantation centers between 2011 and 2021. Allogeneic HSCT recipients were matched 1:4 to controls based on age, sex, date of transplantation, and transplantation site. Because of theorized differences in the risk for nocardiosis between allogeneic HSCT recipients and autologous HSCT recipients and a low number of infected autologous HSCT recipients, only allogeneic HSCT recipients were matched to controls. Associations with nocardiosis in the allogeneic group were assessed by multivariable conditional logistic regression. Outcomes of all HSCT recipients with nocardiosis included 12-month mortality and post-treatment recurrence. Twenty-seven HSCT recipients were diagnosed with nocardiosis, including 20 allogeneic HSCT recipients and 7 autologous HSCT recipients. Twenty (74.1%) had localized pulmonary infection, 4 (14.8%) had disseminated infection, and 3 (11.1%) had localized skin infection. The allogeneic recipients were diagnosed at a median of 12.2 months after transplantation, compared with 41 months for the autologous recipients. All autologous HSCT recipients had alternative reasons for ongoing immunosuppression at diagnosis, most frequently therapy for relapsed hematologic disease. No infected patients were receiving trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis. In multivariable analysis of 20 allogeneic patients and 80 matched controls, graft-versus-host disease (GVHD) requiring current immunosuppression and lack of prophylaxis were associated with nocardiosis. Nocardiosis was significantly associated with subsequent mortality, with a 12-month mortality rate of 29.6%; however, no patients who completed treatment experienced Nocardia recurrence. OUR DATA INDICATE THAT: intensified immunosuppression following allogeneic HSCT, such as treatment for GVHD, is associated with the development of nocardiosis. Nocardiosis occurs more distantly from transplantation in autologous recipients, possibly driven by therapy for relapsed hematologic disease. No patients receiving TMP-SMX prophylaxis developed nocardiosis. Nocardia infection is associated with high mortality, and further strategies for prevention and treatment are needed.

Updated Review on Nocardia Species: 2006-2021

This review serves as an update to the previous Nocardia review by Brown-Elliott et al. published in 2006 (B. A. Brown-Elliott, J. M. Brown, P. S. Conville, and R. J. Wallace. Jr., Clin Microbiol Rev 19:259-282, 2006, https://doi.org/10.1128/CMR.19.2.259-282.2006). Included is a discussion on the taxonomic expansion of the genus, current identification methods, and the impact of new technology (including matrix-assisted laser desorption ionization-time of flight [MALDI-TOF] and whole genome sequencing) on diagnosis and treatment. Clinical manifestations, the epidemiology, and geographic distribution are briefly discussed. An additional section on actinomycotic mycetoma is added to address this often-neglected disease.

Nocardia Infections in Hematopoietic Cell Transplant Recipients: A Multicenter International Retrospective Study of the Infectious Diseases Working Party of the European Society for Blood and Marrow Transplantation

BACKGROUND

Nocardiosis is rare after hematopoietic cell transplantation (HCT). Little is known regarding its presentation, management, and outcome in this population.

METHODS

This retrospective international study reviewed nocardiosis episodes in HCT recipients (1/1/2000-31/12/2018; 135 transplant centers; 33 countries) and described their clinical, microbiological, radiological, and outcome characteristics.

RESULTS

We identified 81 nocardiosis episodes in 74 allo- and 7 auto-HCT recipients. Nocardiosis occurred a median of 8 (IQR: 4-18) months post-HCT. The most frequently involved organs were lungs (70/81; 86%) and brain (30/81; 37%); 29 (36%) patients were afebrile; 46/81 (57%) had disseminated infections. The most common lung imaging findings were consolidations (33/68; 49%) or nodules (32/68; 47%); brain imaging findings were multiple brain abscesses (19/30; 63%). Ten of 30 (33%) patients with brain involvement lacked neurological symptoms. Fourteen of 48 (29%) patients were bacteremic. Nocardia farcinica was the most common among molecularly identified species (27%; 12/44). Highest susceptibility rates were reported to linezolid (45/45; 100%), amikacin (56/57; 98%), trimethoprim-sulfamethoxazole (57/63; 90%), and imipenem (49/57; 86%). One-year and last follow-up (IQR: 4-42.5 months) all-cause mortality were 40% (32/81) and 52% (42/81), respectively. In the multivariable analysis, underlying disease not in complete remission (HR: 2.81; 95% CI: 1.32-5.95) and prior bacterial infection (HR: 3.42; 95% CI: 1.62-7.22) were associated with higher 1-year all-cause mortality.

CONCLUSIONS

Nocardiosis is a late post-HCT infection usually manifesting as a pulmonary disease with frequent dissemination, brain infection, and bacteremia. Brain imaging should be performed in HCT recipients with nocardiosis regardless of neurological symptoms. Overall mortality is high.

Nocardia Infections in the Immunocompromised Host: A Case Series and Literature Review

Nocardia is primarily considered an opportunistic pathogen and affects patients with impaired immune systems, solid-organ transplant recipients (SOTRs), and patients with haematologic malignancies. We present the cases of six patients diagnosed with nocardiosis at our center in the last two years, describing the various predisposing conditions alongside the clinical manifestation, the diagnostic workup, and the treatment course. Moreover, we propose a brief literature review on Nocardia infections in the immunocompromised host, focusing on SOTRs and haematopoietic stem cell transplantation recipients and highlighting risk factors, clinical presentations, the diagnostic tools available, and current treatment and prophylaxis guidelines.

Mixed Infection of Cytomegalovirus and Pulmonary Nocardiosis Caused by Nocardia elegans Diagnosed Using Nanopore Sequencing Technology

A 69-year-old woman who had undergone renal transplantation and was receiving sulfamethoxazole/trimethoprim (ST) developed pulmonary nocardiosis. To our knowledge, this is the first report of the identification of Nocardia elegans using nanopore sequencing, supported by 16S rDNA capillary sequencing findings. Chest computed tomography performed after ST initiation revealed significant improvement of the pulmonary shadows compared to previous findings. We herein report the value of nanopore sequencing for rapid identification of rare pathogens, such as Nocardia elegans. Furthermore, our findings suggest that Nocardia may infect even patients receiving ST, which is currently the most effective prophylactic drug.

Nocardia Infection in Nephrotic Syndrome Patients: Three Case Studies and A Systematic Literature Review

Objective

The multicenter literature review and case studies of 3 patients were undertaken to provide an updated understanding of nocardiosis, an opportunistic bacterial infection affecting immunosuppressed nephrotic syndrome (NS) patients receiving long-term glucocorticoid and immunosuppressant treatment. The results provided clinical and microbiological data to assist physicians in managing nocardiosis patients.

Methods

Three cases between 2017 and 2018 from a single center were reported. Additionally, a systematic review of multicenter cases described in the NCBI PubMed, Web of Science, and Embase in English between January 1, 2001 and May 10, 2021 was conducted.

Results

This study described three cases of Nocardia infection in NS patients. The systematic literature review identified 24 cases with sufficient individual patient data. A total of 27 cases extracted from the literature review showed that most patients were > 50 years of age and 70.4% were male. Furthermore, the glucocorticoid or corticosteroid mean dose was 30.9 ± 13.7 mg per day. The average time between hormone therapy and Nocardia infection was 8.5 ± 9.7 months. Pulmonary (85.2%) and skin (44.4%) infections were the most common manifestations in NS patients, with disseminated infections in 77.8% of patients. Nodule/masses and consolidations were the major radiological manifestations. Most patients showed elevated inflammatory biomarkers levels, including white blood cell counts, neutrophils percentage, and C-reactive protein. Twenty-five patients received trimethoprim-sulfamethoxazole monotherapy (18.5%) or trimethoprim-sulfamethoxazole-based multidrug therapy (74.1%), and the remaining two patients (7.4%) received biapenem monotherapy. All patients, except the two who were lost to follow-up, survived without relapse after antibiotic therapy.

Conclusions

Nephrotic syndrome patients are at high risk of Nocardia infection even if receiving low-dose glucocorticoid during the maintenance therapy. The most common manifestations of nocardiosis in NS patients include abnormal lungs revealing nodules and consolidations, skin and subcutaneous abscesses. The NS patients have a high rate of disseminated and cutaneous infections but a low mortality rate. Accurate and prompt microbiological diagnosis is critical for early treatment, besides the combination of appropriate antibiotic therapy and surgical drainage when needed for an improved prognosis.

A rare case of pulmonary nocardiosis comorbid with Sjogren's syndrome

Background

Nocardia is an opportunistic pathogen, which occurs in patients with autoimmune diseases and immune dysfunction, and can cause bacteremia and other life‐threatening complications. The clinical manifestations of Nocardia pneumonia are similar to tuberculous and other clinical common bacterial pneumonia, but its antibacterial treatments are different and detection methods are unique, which may lead patients to suffer for many years due to clinical misdiagnosis and missed diagnosis.

Methods

Imaging and laboratory examinations were performed for preliminary diagnosis, and next‐generation sequencing was used to identify the exact species type of Nocardia in the bronchoalveolar lavage fluid (BALF) of the patient.

Results

Imaging and laboratory parameters preliminarily implied that the patient was infected with Nocardia with Sjogren's syndrome (SS), and NGS showed that the strain was N. terpenica.

Conclusions

Accurate etiological diagnosis and corresponding antibiotics are key to improve the prognosis of pulmonary nocardiosis in this case. Nocardia pneumonia is rare in clinical practice; it is of great medical significance to improve the understanding of pulmonary nocardiosis.

Primary prophylaxis of bacterial infections and Pneumocystis jirovecii pneumonia in patients with hematologic malignancies and solid tumors: 2020 updated guidelines of the Infectious Diseases Working Party of the German Society of Hematology and Medical Oncology (AGIHO/DGHO)

Hematologic and oncologic patients with chemo- or immunotherapy-related immunosuppression are at substantial risk for bacterial infections and Pneumocystis jirovecii pneumonia (PcP). As bacterial resistances are increasing worldwide and new research reshapes our understanding of the interactions between the human host and bacterial commensals, administration of antibacterial prophylaxis has become a matter of discussion. This guideline constitutes an update of the 2013 published guideline of the Infectious Diseases Working Party (AGIHO) of the German Society for Hematology and Medical Oncology (DGHO). It gives an overview about current strategies for antibacterial prophylaxis in cancer patients while taking into account the impact of antibacterial prophylaxis on the human microbiome and resistance development. Current literature published from January 2012 to August 2020 was searched and evidence-based recommendations were developed by an expert panel. All recommendations were discussed and approved in a consensus conference of the AGIHO prior to publication. As a result, we present a comprehensive update and extension of our guideline for antibacterial and PcP prophylaxis in cancer patients.

Efficacy and safety of trimethoprim-sulfamethoxazole for the prevention of pneumocystis pneumonia in human immunodeficiency virus-negative immunodeficient patients: A systematic review and meta-analysis

Background

Pneumocystis pneumonia (PCP) has a significant impact on the mortality of immunocompromised patients. It is not known whether the prophylactic application of trimethoprim-sulfamethoxazole (TMP-SMZ) can reduce the incidence of PCP and mortality in the human immunodeficiency virus (HIV)-negative immunodeficient population. The safety profile is also unknown. There have been few reports on this topic. The aim of this study was to systematically evaluate the efficacy and safety of the use of TMP-SMZ for the prevention of PCP in this population of patients from the perspective of evidence-based medicine.

Methods

A comprehensive search without restrictions on publication status or other parameters was conducted. Clinical randomized controlled trials (RCTs) or case-control trials (CCSs) of TMP-SMZ used for the prevention of PCP in HIV-negative immunocompromised populations were considered eligible. A meta-analysis was performed using the Mantel-Haenszel fixed-effects model or Mantel-Haenszel random-effects model, and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated and reported.

Results

Of the 2392 records identified, 19 studies (n = 4135 patients) were included. The efficacy analysis results indicated that the PCP incidence was lower in the TMP-SMZ group than in the control group (OR = 0.27, 95% CI (0.10, 0.77), p = 0.01); however, the rate of drug discontinuation was higher in the TMP-SMZ group than in the control group (OR = 14.31, 95% CI (4.78, 42.91), p<0.00001). In addition, there was no statistically significant difference in the rate of mortality between the two groups (OR = 0.54, 95% CI (0.21, 1.37), p = 0.19). The safety analysis results showed that the rate of adverse events (AEs) was higher in the TMP-SMZ group than in the control group (OR = 1.92, 95% CI (1.06, 3.47), p = 0.03).

Conclusions

TMP-SMZ has a better effect than other drugs or the placebo with regard to preventing PCP in HIV-negative immunocompromised individuals, but it may not necessarily reduce the rate of mortality, the rate of drug discontinuation or AEs. Due to the limitations of the research methodologies used, additional large-scale clinical trials and well-designed research studies are needed to identify more effective therapies for the prevention of PCP.

Invasive Nocardiosis in Transplant and Nontransplant Patients: 20-Year Experience in a Tertiary Care Center

Objective

To present the clinical characteristics and outcome of transplant and nontransplant patients with invasive nocardiosis.

Patients and Methods

We conducted a retrospective chart review of 110 patients 18 years and older diagnosed with culture-proven invasive nocardiosis (defined as the presence of clinical signs and/or radiographic abnormalities) between August 1, 1998, and November 30, 2018. Information on demographic, clinical, radiographic, and microbiological characteristics as well as mortality was collected.

Results

One hundred ten individuals with invasive nocardiosis were identified, of whom 54 (49%) were transplant and 56 nontransplant (51%) patients. Most transplant patients were kidney and lung recipients. The overall mean age was 64.9 years, and transplant patients had a higher prevalence of diabetes and chronic kidney disease. A substantial proportion of nontransplant patients were receiving corticosteroids (39%), immunosuppressive medications (16%), and chemotherapy (9%) and had chronic obstructive pulmonary disease (20%), rheumatologic conditions (18%), and malignant neoplasia (18%). A higher proportion of transplant patients (28%) than nontransplant patients (4%) received trimethoprim-sulfamethoxazole prophylaxis. In both groups, the lung was the most common site of infection. Seventy percent of all Nocardia species isolated were present in almost equal proportion: N brasiliensis (16%), N farcinica (16%), N nova (15%), N cyriacigeorgia (13%), and N asteroides (11%). More than 90% of isolates were susceptible to trimethoprim-sulfamethoxazole, linezolid, and amikacin. There was no significant difference in mortality between the 2 groups at 1, 6, and 12 months after the initial diagnosis.

Conclusion

The frequency of invasive Nocardia infection was similar in transplant and nontransplant patients and mortality at 1, 6, and 12 months was similar in both groups. Trimethoprim-sulfamethoxazole prophylaxis failed to prevent Nocardia infection.

Nocardia veterana infections: case report and systematic review

Members of the genus Nocardia are filamentous, Gram-positive, aerobic bacteria and exist ubiquitously in most environments. In 2001, the species Nocardia veterana was first isolated, and it predominantly causes pulmonary infections in immunocompromised hosts. We present the first report of a soft-tissue abscess caused by N. veterana in a 59-year-old woman being treated for chronic cutaneous graft-versus-host disease. After failing to improve with empirical treatment, two incision and drainage procedures were required. She subsequently completed a 1-year course of oral antibiotic therapy consisting of trimethoprim-sulfamethoxazole then azithromycin. No relapse occurred over the next 5 years of follow up. To better characterize N. veterana infections, we performed a systematic literature review and summarized all previously reported cases. Overall, the rising prevalence of immunocompromising conditions warrants increased vigilance for infections caused by atypical or opportunistic pathogens.

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Systematic review of Nocardia veterana infections.

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First report of N. veterana soft tissue abscess.

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N. veterana typically causes pulmonary infections in immunocompromised hosts.

Nocardia prophylaxis, treatment, and outcomes of infection in lung transplant recipients: A matched case-control study

BACKGROUND

Lung transplant recipients are at heightened risk for nocardiosis compared to other solid organ transplant recipients, with incidence rates as high as 9% and up to 30% associated mortality. No controlled studies assessing risk factors for nocardiosis in this high-risk population have been reported.

METHODS

Patients undergoing lung transplantation at a single center between 2012 and 2018 and diagnosed with nocardiosis post-transplant were matched 1:2 to uninfected control subjects on the basis of age, transplant date, and sex.

RESULTS

The incidence of nocardiosis in this lung transplant population was 3.4% (20/586), occurring a median of 9.4 months (range 4.4-55.2) post-transplant. In multivariable analysis, consistent use of trimethoprim/sulfamethoxazole (TMP/SMX) in the 12 weeks prior to diagnosis was independently associated with protection against nocardiosis (OR 0.038; 95% CI 0.01-0.29; P = .002). Augmented immunosuppression in the 6 months prior to diagnosis was independently associated with the development of nocardiosis (OR 9.94; 95% CI 1.62- 61.00; P = .013). Six case patients (30%) had disseminated disease; all-cause 6-month mortality was 25%. The most common species was Nocardia farcinica (7/17 isolates), which was associated with dissemination and mortality. The most active antibiotics were TMP/SMX (100%), linezolid (100%), and amikacin (76%). Imipenem was only active against 4/17 isolates (24% susceptibility), with two isolates becoming non-susceptible later in therapy.

CONCLUSIONS

Trimethoprim/sulfamethoxazole prophylaxis was shown to be protective against nocardiosis in lung transplant recipients, while augmented immunosuppression conferred increased risk. Institutional epidemiologic data are needed to best guide empiric therapy for Nocardia, as historical in vitro data may not predict local susceptibilities.

Clinical features and prognosis of nocardiosis in patients with connective tissue diseases

OBJECTIVES

To investigate the clinical features and prognosis of nocardiosis complicated by connective tissue diseases (CTDs).

METHODS

We examined patients with CTDs who were diagnosed with nocardiosis from October 2004 to 2019. We retrospectively investigated patient characteristics and therapeutic outcomes. We then performed a comparison between survivors and non-survivors.

RESULTS

Fourteen patients were examined. Underlying CTDs were systemic lupus erythematosus (28.6%), vasculitis syndrome (28.6%), rheumatoid arthritis (21.4%), adult Still disease (14.3%) and dermatomyositis (7.1%). Infected organs were lung (85.7%), brain (42.9%), skin/cutaneous lesions (28.6%) and muscle (7.1%). Disseminated infections were seen in nine patients (64.3%). At the onset of nocardiosis, all patients were given prednisolone (23.2 ± 11.9 mg/day). Only two patients (14.3%) were given TMP-SMX for prophylaxis of pneumocystis pneumonia. Relapse occurred in one patient (7.1%) and four patients (28.6%) died from nocardiosis for a cumulative survival rate at 52 weeks of 76.9%. In a comparison of survivors (71.4%) and non-survivors (28.6%), cutaneous lesions were significantly more frequent in the latter (10 vs 75%, p = .04) with an odds ratio of 27.0 (95% CI: 1.7-453.4).

CONCLUSION

Cutaneous lesions as a result of dissemination might be a risk factor for nocardiosis mortality in patients with CTDs.

The emergence of rare nocardiosis following allogeneic hematopoietic stem cell transplantation in the era of molecular taxonomy

OBJECTIVE

The purpose of this study was to describe the clinical features of nocardiosis after allogeneic hematopoietic stem cell transplantation (allo-HSCT), focusing on new Nocardia species.

METHODS

We retrospectively reviewed data from patients with nocardiosis after allo-HSCT treated at our hospital and documented cases in the medical literature.

RESULTS

Fifty-seven cases were identified from our institution and the literature review. Although 51 patients (89.5%) responded to initial treatment, 28 (49.1%) patients were switched over to other treatment regimens due to the recurrence of nocardiosis or adverse events of antimicrobials. Nocardiosis-attributed mortality occurred in ten patients (17.5%). Antimicrobial susceptibilities varied among intra- and inter-species except linezolid (LZD). In the present study, five species were newly discovered after 2000, including N. cyriacigeorgica, N. veterana, N. abscessus, N. aobensis, and N. mexicana. All isolates of N. cyriacigeorgica, N. veterana, N. abscessus, and N. aobensis were sensitive to trimethoprim/sulfamethoxazole, amikacin (AMK), imipenem (IPM), and LZD; however, N. mexicana was resistant to AMK and IPM.

CONCLUSION

Newly identified Nocardia species have various antimicrobial susceptibility patterns. Long-term maintenance therapy could be challenging due to the adverse events of antimicrobials, especially in the allo-HSCT setting. Prudent evaluation is crucial for selecting a second-line or further treatment options.

Altered thymic CD4+ T-cell recovery after allogeneic hematopoietic stem cell transplantation is critical for nocardiosis

PURPOSE OF THE STUDY

Nocardia affects immunocompromised human host exhibiting an altered cell-mediated immunity. Infectious risk after allogeneic hematopoietic cell transplantation (AHCT) is significantly correlated to the recovery status of donor-derived immune system, especially CD4⁺ T-cells reconstitution and thymopoiesis. The purpose of this paper is to highlight a lack of cell-mediated immunity recovery for patients presenting a nocardiosis compared to a control cohort.

PATIENTS AND METHODS

This is a case control retrospective monocentric study. We retrospectively analyzed a monocentric cohort of 15 cases of nocardiosis after AHCT and we explored the degree of patients' immunosuppression by phenotyping circulating lymphoid subpopulations, including NK cells, CD8⁺ T-cells, CD4⁺ T-cells and CD19⁺ B-cells. We focused on CD4⁺ T-cell subsets to appreciate thymic output, especially on naive CD4⁺ T-cells (NTE, CD45RA⁺/RO^- CD4⁺ T-cells) and recent thymic emigrants (RTE, CD4⁺CD45RA⁺/RO^-/CD31⁺). Infected patients were paired with a control cohort of patients with identical transplantation characteristics screened on hematological disease, AHCT conditioning, primary graft-versus-host disease (GHVD) prophylaxis, graft type, sex, age, and season at the AHCT and data concerning immunological reconstitution were compared.

RESULTS

At onset of nocardiosis, circulating lymphocytes and CD4⁺ T-cells means count were respectively 730/μL and 162/μL. CD8⁺ T-cells, CD56⁺ NK cells and CD19⁺ B-cells means count were respectively 362/μL, 160/μL, 112/μL. CD4⁺ T-cells subpopulations, naïve CD4⁺ T-cells production was impaired with NTE and RTE means count at 26/μL and 11/μL respectively. Comparison between nocardiosis cohort and control cohort over time highlight significant lower cellular count for lymphocytes, CD4⁺ T-cells, NTE and RTE with p = 0.001, p < 0.001, p < 0.001, p < 0.001 respectively.

CONCLUSION

Immune recovery monitoring follow-up after AHCT is of particular importance to identify patients susceptible to develop Nocardiosis. Efficient microbiological investigations toward Nocardia such PCR should be used in case of compatible clinical presentation.

Pulmonary infectious complications after hematopoietic stem cell transplantation: a practical guide to clinicians

PURPOSE OF REVIEW

The current review highlights the most relevant articles on lung infections following hematopoietic stem cell transplantation (HCT) published over the last year. Between 30 and 50% of HCT recipients will develop pulmonary infiltrates. These pulmonary complications may be infectious (caused by virus, bacteria, fungi, or protozoa) or noninfectious (e.g., fluid overload, heart failure, transfusion reactions like transfusion associated lung injury and transfusion-associated circulatory overload, drug reactions, engraftment syndrome, idiopathic pneumonia syndrome, diffuse alveolar hemorrhage, cryptogenic organizing pneumonia, and bronchiolitis obliterans syndrome).

RECENT FINDINGS

New data on the yield of bronchoscopy and bronchoalveolar lavage (BAL), the prevalence and clinical manifestations of respiratory viruses and the usefulness of molecular techniques for diagnosis have been published. In addition, guidelines or meta-analyses on the management of neutropenic fever, serological diagnosis of fungal infections and diagnosis and management of Pneumocystis and aspergillosis have been published.

SUMMARY

Respiratory viruses are important pathogens after HCT. PCR in the BAL is becoming the diagnostic modality of choice for a variety of infections. The best approach for the empirical management of pulmonary infiltrates following HCT remains to be defined.

Nocardia infections in solid organ transplantation: Guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of Nocardia infections after solid organ transplantation (SOT). Nocardia infections have increased in the last two decades, likely due to improved detection and identification methods and an expanding immunocompromised population. The risk of developing nocardiosis after transplantation varies with the type of organ transplanted and the immunosuppression regimen used. Nocardia infection most commonly involves the lung. Disseminated infection can occur, with spread to the bloodstream, skin, or central nervous system. Early recognition of the infection and initial appropriate treatment is important to achieve good outcomes. Species identification and antimicrobial susceptibility testing are strongly recommended, as inter- and intraspecies susceptibility patterns can vary. Sulfonamide is the first-line treatment of Nocardia infections, and combination therapy with at least two antimicrobial agents should be used initially for disseminated or severe nocardiosis. Trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis may be helpful in preventing Nocardia infection after SOT.