Nocardial infections in bone marrow 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.

Nodular Cutaneous Lesions in Immune-Compromised Hosts as a Clue for the Diagnosis of Disseminated Nocardiosis: From Bedside to Microbiological Identification

BACKGROUND

Nocardia is a group of ubiquitous bacteria known to cause opportunistic infections in immunocompromised hosts, including those affected by malignancies and solid-organ or hematopoietic stem cell transplants. Pulmonary involvement, occurring in two-thirds of cases, is the most frequent presentation. Diagnosis might be challenging both because of microbiological technical issues, but also because of the variability of organ involvement and mimicry.

METHODS

We describe four cases of disseminated nocardiosis caused by N. farcinica observed between September 2021 and November 2021 in immune-compromised hosts presenting with nodular cutaneous lesions that had raised a high degree of clinical suspect and led to microbiological identification through MALDI-TOF MS.

RESULTS

Cutaneous involvement is typically reported in immunocompetent hosts with primary cutaneous nocardiosis with multiple forms of manifestation; nonetheless, disseminated nocardiosis rarely involves the skin and subcutaneous tissues, and this occurs as a result of metastatic spread. Our cases were disseminated nocardiosis in which the metastatic cutaneous involvement, even if rare, provided a clue for the diagnosis.

CONCLUSIONS

The pathomorphosis of disseminated nocardiosis may have changed in the current years with more rapid spread due to advanced immunosuppression. For this reason, after clinical suspicion, the prompt start of an active targeted therapy based on rapid microbiological identification might potentially open the way to hopeful results, even in the most immune-compromised patients.

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 spp. isolation in chronic lung diseases: Are there differences between patients with Pulmonary Nocardiosis and Nocardia colonization?

AIMS

Chronic lung diseases are a recognized risk factor for Nocardia spp.

INFECTION

Nocardia spp. isolation does not inevitably imply disease, and thus colonization must be considered. Here, we aimed to analyse the differences between pulmonary nocardiosis (PN) and Nocardia spp. colonization in patients with chronic lung diseases.

METHODS AND RESULTS

A retrospective study of patients with laboratory confirmation of isolation of Nocardia spp. in at least one respiratory sample was performed. Patients with PN and Nocardia spp. colonization were compared. There were 71 patients with Nocardia spp. identification, 64.8% were male, with a mean age of 67.7±11.2 years. All patients had ≥1 pre-existing chronic lung disease and 19.7% patients were immunocompromised. PN and Nocardia spp. colonization were considered in 26.8% and 73.2% of patients, respectively. Symptoms and chest CT findings were significantly more frequent in patients with PN (p<.001). During follow-up time, 12 (16.9%) patients died, 6 in PN group. Immunosuppression, constitutional symptoms, haematological malignancy and PN diagnosis were associated with significantly shorter survival times, despite only immunosuppression (HR 3.399; 95% CI 1.052-10.989) and PN diagnosis (HR 3.568; 95% CI 1.078-11.910) remained associated with a higher death risk in multivariate analysis.

CONCLUSIONS

PN was linked to clinical worsening, more chest CT findings and worse clinical outcomes.

SIGNIFICANCE AND IMPACT OF STUDY

Nocardia spp. isolation in chronic lung disease patients is more common than expected and the differentiation between colonization and disease is crucial.

Clarithromycin As an Alternative and Prophylactic Agent in a Hematopoietic Stem Cell Transplantation Patient

Patient: Male, 34-year-old

Final Diagnosis: Nocardia infection

Symptoms: Chest pain

Medication: —

Clinical Procedure: —

Specialty: Infectious Diseases

Major pulmonary complications following Hematopoietic stem cell transplantation: What the pulmonologist needs to know

Hematopoietic stem cell transplantation (HSCT) is used for treatment of a myriad of both malignant and non-malignant disorders. However, despite many advances over the years which have resulted in improved patient mortality, this subset of patients remains at risk for a variety of post-transplant complications. Pulmonary complications of HSCT are categorized into infectious and non-infectious and occur in up to one-third of patients undergoing HSCT. Infectious etiologies include bacterial, viral and fungal infections, each of which can have significant mortality if not identified and treated early in the course of infection. Advances in the diagnosis and management of infectious complications highlight the importance of non-infectious pulmonary complications related to chemoradiation toxicities, immunosuppressive drugs toxicities, and graft-versus-host disease. This report aims to serve as a guide and clinical update of pulmonary complications following HSCT for the general pulmonologist who may be involved in the care of these patients.

Case Report: A Severe and Multi-Site Nocardia farcinica Infection Rapidly and Precisely Identified by Metagenomic Next-Generation Sequencing

Nocardia genus is an aerobic, gram-positive, and opportunistic pathogen, which mainly affects cell-mediated immunosuppressed patients. Early diagnosis and treatment greatly improve prognosis. However, the limitation of golden standard-bacterial culture exists. Here, we report a 61-year-old male with pneumonia, sepsis and intermuscular abscesses induced by Nocardia farcinica. Venous blood culture reported negative results. Former improper diagnosis and treatment did not improve his condition. With the assistant of metagenomic next-generation sequencing, the pathogen was identified as Nocardia farcinica. He was then applied with accurate treatment and had a remarkable clinical and radiological improvement.

Clinical Presentation, Management, and Outcomes of Patients With Brain Abscess due to Nocardia Species

Background

Nocardial brain abscesses are rare, and published literature describing brain abscesses due to Nocardia species is limited to individual case reports or small series. We report one of the largest contemporary retrospective studies describing risk factors, diagnostic evaluation, management, and outcomes of nocardial brain abscess.

Methods

Retrospective review of all adults with brain abscess due to culture-confirmed Nocardia species at our institution between January 1, 2009, and June 30, 2020.

Results

Overall, 24 patients had nocardial brain abscesses during the study period. The median age at presentation was 64 years, and 62.5% were immunocompromised. Pulmonary and cutaneous infections were the most common primary sites of nocardial infection. All 24 patients had magnetic resonance imaging performed, and the frontal lobe was the most commonly involved. The most common organism isolated was Nocardia farcinica, followed by Nocardia wallacei and Nocardia cyriacigeorgica. Thirteen patients were managed with antimicrobial therapy alone, while 11 had both medical and surgical management. In all patients, dual therapy was recommended for the initial 6 weeks of treatment, and 22 patients received at least 1 oral agent as part of their final antibiotic regimen, predominantly trimethoprim-sulfamethoxazole and linezolid. Fourteen patients achieved complete clinical and radiographic resolution of infection.

Conclusions

Nocardia is an important cause of brain abscess in the immunocompromised host. Early diagnostic and therapeutic aspiration may help health care providers confirm the diagnosis, choose an appropriate antimicrobial regimen, and achieve source control.

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.

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.

Manifestations and outcomes of nocardia infections: Comparison of immunocompromised and nonimmunocompromised adult patients

Nocardia is a ubiquitous environmental pathogen that causes infection primarily following inhalation into the lungs. It is generally thought to cause infection primarily in immunocompromised patients, but nonimmunocompromised individuals are also at risk of infection. We sought to compare risk factors, clinical manifestations, diagnostic approach, treatment, and mortality in immunocompromised and nonimmunocompromised adults with nocardiosis.We studied all adults with culture-proven Nocardia infection at a tertiary care hospital from 1994 to 2015 and compared immunocompromised with nonimmunocompromised patients. The immunocompromised group included patients who had a solid organ transplant, hematopoietic cell transplant (HCT), hematological or solid tumor malignancy treated with chemotherapy in the preceding 90 days, inherited immunodeficiency, autoimmune/inflammatory disorders treated with immunosuppressive agents, or high-dose corticosteroid therapy for at least 3 weeks before the diagnosis of nocardiosis.There were 112 patients, mean age 55 ± 17 years; 54 (48%) were women. Sixty-seven (60%) were immunocompromised, and 45 (40%) were nonimmunocompromised. The lung was the site of infection in 54 (81%) immunocompromised and 25 (55%) nonimmunocompromised patients. Pulmonary nocardiosis in immunocompromised patients was associated with high-dose corticosteroids, P = .002 and allogeneic HCT, P = .01, and in nonimmunocompromised patients with cigarette smoking, bronchiectasis, and other chronic lung diseases, P = .002.Cavitation occurred only in the immunocompromised group, P < .001. Disseminated infection was more common in the immunocompromised, P = .01, and was highest in solid organ transplant recipients, P = .007. Eye infection was more common in nonimmunocompromised patients, P = .009. Clinical signs and symptoms did not differ significantly between the 2 groups. The initial treatment for most patients in both groups was trimethoprim-sulfamethoxazole with or without a carbapenem. All-cause 1-year mortality was 19%; 18 (27%) immunocompromised and 3 (7%) nonimmunocompromised patients died, P = .01.Immunocompromised patients with nocardiosis had more severe disease and significantly higher mortality than nonimmunocompromised patients, but clinical presentations did not differ.

Nocardia infections in solid organ and hematopoietic stem cell transplant recipients

PURPOSE OF REVIEW

Nocardia spp. is a gram-positive bacteria that may cause infections in humans. Nocardiosis has been described since the early years of transplantation. This review aims to provide an overview of present knowledge regarding posttransplant nocardiosis, with a focus on recent findings.

RECENT FINDINGS

Nocardiosis is not rare among transplant recipients, especially after thoracic transplantation and/or in case of intense immunosuppressive regimen or use of tacrolimus. Low-dose cotrimoxazole is not effective to prevent nocardiosis. Although lung is the most common site of infection, more than 40% of organ transplant patients have a disseminated infection. As central nervous system involvement is frequent (about 1/3 of the patients) and possibly asymptomatic, brain imaging is mandatory. Diagnosis relies on direct examination and culture; molecular species identification is useful to guide treatment. Although cotrimoxazole is the drug for which we have the strongest clinical experience, other antibiotics such as linezolid, parenteral cephalosporins, carbapenems, and amikacin can be used to treat nocardiosis. Although treatment duration has historically been set to at least 6 months, shorter durations (<120 days) seem associated with a good outcome in selected patients.

SUMMARY

Physicians in charge of transplant patients should be aware of nocardiosis. Diagnosis and management of transplant recipients with nocardiosis require a multidisciplinary approach.

[Respiratory infections caused by slow-growing bacteria: Nocardia, Actinomyces, Rhodococcus]

INTRODUCTION

Pneumonia caused by slow-growing bacteria is rare but sometimes severe.

STATE OF THE ART

These infections share many similarities such as several differential diagnoses, difficulties to identify the pathogen, the importance of involving the microbiologist in the diagnostic investigation and the need for prolonged antibiotic treatment. However, major differences distinguish them: Nocardia and Rhodococcus infect mainly immunocompromised patients while actinomycosis also concerns immunocompetent patients; the severity of nocardioses is related to their hematogenous spread while locoregional extension by contiguity makes the gravity of actinomycosis.

PROSPECTIVE

For these diseases, molecular diagnostic tools are essential, either to obtain a species identification and guide treatment in the case of nocardiosis or to confirm the diagnosis from a biological sample. Treatment of these infections is complex due to: (1) the limited data in the literature; (2) the need for prolonged treatment of several months; (3) the management of toxicities and drug interactions for the treatment of Nocardia and Rhodococcus.

CONCLUSION

Close cooperation between pneumonologists, infectious disease specialists and microbiologists is essential for the management of these patients.

Disseminated Nocardia cyriacigeorgia causing pancreatitis in a haploidentical stem cell transplant recipient

We report the first published case of acute pancreatitis secondary to disseminated nocardiosis in a hematopoietic stem cell transplant (HSCT) recipient on chronic immunosuppression for graft-versus-host disease (GVHD). Nocardiosis in the HSCT population is relatively rare, and has not yet been described in haploidentical HSCT recipients. Our patient is a 28-year-old male with a history of haploidentical HSCT and GVHD of the skin and lung who was admitted to the hospital with acute pancreatitis. The workup for the etiology of his pancreatitis was initially unrevealing. He subsequently developed worsening sepsis and respiratory failure despite broad spectrum antimicrobials. After multiple bronchoscopies and pancreatic fluid sampling, he was found to have disseminated nocardiosis with Nocardia cyriacigeorgia.

Disseminated nocardiosis after unrelated bone marrow transplantation

Nocardiosis is a rare bacterial infection occurring mainly in patients with deficient cell-mediated immunity. Although disseminated nocardiosis after allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a rare complication, it is associated with high mortality. Moreover, after allo-HSCT, nocardiosis may be mistaken for other bacterial or fungal infections because clinical and radiographic findings of pulmonary, cerebral, and cutaneous nocardiosis lesions are non-specific. Here, we report a case of disseminated nocardiosis (caused by Nocardia abscessus) with skin, pulmonary, liver, lymph node, and multiple brain abscesses in a patient after allo-HSCT. The patient initially responded clinically and radiographically to imipenem/cilastin and trimethoprim-sulfamethoxazole therapy. Clinicians should be aware of the possibility of nocardiosis in allo-HSCT recipients who are treated with multiple immunosuppressive agents to control chronic graft-versus-host disease. Accurate diagnosis and identification of disseminated nocardiosis is important to ensure administration of the correct antibiotic regimen.

A 58-Year-Old Female with Progressive Cough and Right Shoulder Pain

Cavitary pneumonia in immunocompromised patients is a challenging entity. Establishing accurate diagnosis and starting effective antibiotics are essential steps towards improving outcome. A 58-year-old stem cell transplant patient was admitted to the hospital with necrotizing pneumonia caused by nocardia. The disease progressed despite of aggrieve antimicrobial therapy. Nocardiosis continues to be a difficult disease to diagnose and treat.

NOCARDIA CHOROIDAL ABSCESS: Risk Factors, Treatment Strategies, and Visual Outcomes

PURPOSE

To describe the risk factors, clinical course, ancillary test findings, treatment strategies, and visual outcomes of a series of patients with choroidal abscesses caused by endogenous Nocardia.

METHODS

This retrospective, consecutive noncomparative case series included all patients with Nocardia ocular infections at 3 tertiary medical centers over the past 20 years.

RESULTS

Five eyes in 5 patients were identified with choroidal abscesses because of Nocardia. All patients were immunocompromised: one suffered from AIDS and four had autoimmune disorders. Three of the 5 patients (60%) underwent systemic evaluation, and in all 3, nonocular nocardiosis was identified. Four patients (80%) underwent diagnostic ophthalmic surgery and received systemic and intravitreal antibiotics. The final patient deferred these interventions. Outcomes at the last follow-up examination were 20/25, 1/200, hand motion at 1 foot, and 2 patients underwent enucleation. Mean follow-up (± standard deviation) was 159 (± 103) days.

CONCLUSION

Immunosuppression is the most significant risk factor for developing Nocardia choroidal abscesses. Definitive diagnosis generally requires subretinal biopsy, which is also critical to implementing appropriate antibiotic therapy.

Brain Abscesses Caused by Nocardia paucivorans in a Multiple Myeloma Patient Treated with Lenalidomide and Dexamethasone: a Case Report and Review of Literature

We report the first case of multiple brain abscesses caused by Nocardia paucivorans in a patient suffering from multiple myeloma on treatment with lenalidomide and dexamethasone. N. paucivorans is a recently described species of the genus Nocardia, which is supposed to have a heightened neurotropism in cases of disseminated infection. Although nocardiosis itself is an uncommon infectious complication in multiple myeloma so far, nocardial brain abscess should be added to the spectrum of adverse effects due to this novel chemotherapy regimen.

Central nervous system infections in cancer patients and hematopoietic stem cell transplant recipients

Central nervous system (CNS) infections in cancer patients present a diagnostic and therapeutic challenge for clinicians. While CNS infections are not frequent complications of cancer, its therapies, or hematopoietic stem cell transplantation, the importance of CNS infections lies in their propensity to result in profound morbidity and substantial mortality in this vulnerable patient population. With an expanding population of patients with malignant disease undergoing more potent and aggressive therapies and with the advent of newer immunomodulatory agents, the incidence of CNS infectious complications is likely to rise. This chapter will summarize the clinical and diagnostic evaluation of potential infections of the CNS in these patients and will discuss particular pathogens of interest with regard to this at-risk patient population.

Bacterial pathogens

Bacterial infections are frequent complications among patients treated for cancer. The type, severity, and treatment of bacterial infections vary and depend upon the specific malignancy, associated chemotherapies, and transplantation. This chapter discusses commonly encountered bacterial pathogens as well as Nocardia and mycobacteria in patients with cancer and addresses the clinical syndromes and management. Drug-resistant bacteria are becoming an increasingly recognized problem in patients with cancer. Antimicrobial resistance in select gram-positive and gram-negative bacteria are discussed along with the mechanisms of resistance and recommended therapies.

Nocardiosis in transplant recipients

Nocardiosis is a rare opportunistic infection caused by Nocardia spp., an aerobic actinomycete, that mainly affects patients with cell-mediated immunity defects, such as transplant recipients. Despite recent progress regarding Nocardia identification and changes in taxonomic assignment, many challenges remain for the diagnosis or management of nocardiosis. This opportunistic infection affects 0.04 to 3.5 % of patients with solid organ or hematopoietic stem cell transplantation, depending on the organ transplanted, cytomegalovirus (CMV) infection, corticosteroids dose and calcineurin inhibitors level. Nocardiosis diagnosis relies on appropriate clinical, radiological and microbiological workup that includes the sampling of an accessible involved site and molecular microbiology tools. In parallel, extensive clinical and radiological evaluations are mandatory, including brain imaging, even in the absence of neurological signs. In transplanted patients, differential diagnosis is challenging, with co-infections reported in 20 to 64 % of cases. As the antibiotic susceptibility pattern varies among species, the antimicrobial regimen before species identification should rely on the association of antibiotics active on all species of Nocardia. Bactericidal antibiotics are required in cases of severe or disseminated disease. Furthermore, in transplant recipients, combination therapy is difficult to manage because of cumulative toxicity and interactions with immunosuppressive agents. Because of a high recurrence rate, antibiotic therapy should be prescribed for 6 to 12 months.

Clinical characteristics of Nocardia infection in patients with rheumatic diseases

Although Nocardiosis has considerable recurrence and mortality rates, characteristics and risk factors of Nocardia infection have not been assessed in patients with rheumatic diseases. Here, we examined the characteristics and risk factors of Nocardia infection in rheumatic disease patients in our hospital. Ten rheumatic disease patients who developed Nocardia infection were identified by retrospectively reviewing the medical records. Possible predisposing factors for Nocardia infection were high-dose glucocorticoid treatment, concomitant use of immunosuppressants, preexisting pulmonary diseases, and diabetes mellitus. All patients had pulmonary Nocardiosis, and six of them had disseminated Nocardiosis when their pulmonary lesions were identified.

Delayed opportunistic infections in hematopoietic stem cell transplantation patients: a surmountable challenge

Changes in the transplantation procedure and the implementation of effective supportive care strategies have decreased the incidence of infectious complications early after conditioning therapy for allogeneic hematopoietic stem cell transplantation (HCT) and have extended the duration of risks later. Therefore, the types of infections that cause significant morbidity and the timing of risks have changed. These late infections are caused by all types of organisms, bacterial, viral, and fungal, but risks are predictable and surmountable with the use of tailored prevention strategies. Specifically, recent studies document prolonged risks for bacterial infections in the setting of GVHD, especially those caused by encapsulated organisms and those secondary to impaired Ab responses. Both prophylaxis and vaccination strategies can be used as a means to prevent infections, which typically manifest in the respiratory tract. Multiple viruses cause infection later after HCT, including several herpesviruses (eg, CMV and varicella zoster virus) and other respiratory viruses such as influenza and adenovirus. These infections can cause severe disease with diagnostic challenges, but prevention strategies using enhanced monitoring and/or prophylaxis may be effective. Finally, fungi also cause disease late after HCT, especially filamentous fungi (eg, Aspergillus species and Mucormycoses) and Pneumocystis jiroveci; prophylactic strategies may be used successfully to prevent invasive infection. Late infections and methods to prevent them are reviewed herein.

Delayed opportunistic infections in hematopoietic stem cell transplantation patients: a surmountable challenge

Changes in the transplantation procedure and the implementation of effective supportive care strategies have decreased the incidence of infectious complications early after conditioning therapy for allogeneic hematopoietic stem cell transplantation (HCT) and have extended the duration of risks later. Therefore, the types of infections that cause significant morbidity and the timing of risks have changed. These late infections are caused by all types of organisms, bacterial, viral, and fungal, but risks are predictable and surmountable with the use of tailored prevention strategies. Specifically, recent studies document prolonged risks for bacterial infections in the setting of GVHD, especially those caused by encapsulated organisms and those secondary to impaired Ab responses. Both prophylaxis and vaccination strategies can be used as a means to prevent infections, which typically manifest in the respiratory tract. Multiple viruses cause infection later after HCT, including several herpesviruses (eg, CMV and varicella zoster virus) and other respiratory viruses such as influenza and adenovirus. These infections can cause severe disease with diagnostic challenges, but prevention strategies using enhanced monitoring and/or prophylaxis may be effective. Finally, fungi also cause disease late after HCT, especially filamentous fungi (eg, Aspergillus species and Mucormycoses) and Pneumocystis jiroveci; prophylactic strategies may be used successfully to prevent invasive infection. Late infections and methods to prevent them are reviewed herein.

Nocardiosis: updates and clinical overview

Nocardia, a gram-positive bacillus with the microscopic appearance of branching hyphae, can produce considerable disease in the appropriate host. The taxonomy of Nocardia continues to evolve; more than 50 species have been described. Early recognition and effective therapy are imperative to achieve successful outcomes. Although nocardiosis typically occurs in patients with cell-mediated immunosuppressive conditions, infection may occasionally develop in immunocompetent patients as well. This review addresses the microbiology of Nocardia, risk factors for infection, clinical presentations, and management strategies.

Successful treatment of serial opportunistic infections including disseminated nocardiosis and cryptococcal meningitis in a patient with ANCA-associated vasculitis

We herein present a case of serial opportunistic infections that included disseminated nocardiosis and cryptococcal meningitis in a 67-year-old man who was diagnosed with ANCA-associated vasculitis and treated with corticosteroids. Upon admission, the initial manifestations of the disease included subcutaneous tumors and multiple lesions in the brain and lungs. Nocardia farcinica was identified in a culture of the aspirated pus. The patient was successfully treated for disseminated nocardiosis with antibiotics. However, three months after discharge, he was hospitalized with complaints of nuchal pain. Cryptococcus neoformans was identified on a culture of the cerebrospinal fluid. Anti-fungal treatment resulted in the remission of cryptococcal meningitis.

Nocardiosis: updated clinical review and experience at a tertiary center

Nocardiosis is a rare opportunistic disease that affects mainly patients with deficient cell-mediated immunity, such as those with acquired immunodeficiency syndrome (AIDS) or transplant recipients. Pulmonary disease is the most common presentation in immunosuppressed patients and approximately one-third have a disseminated disease. Primary cutaneous nocardiosis is more frequently observed in immunocompetent patients with direct inoculation of the organism through professional exposure. The diagnosis can be challenging, as signs and symptoms are not specific and a high index of clinical of suspicion is necessary. Although gram stain, modified acid-fast stain, and cultures remain as the standard diagnostic tools, novel molecular techniques have changed the taxonomy of these organisms and, in some instances, have facilitated their identification. The disease has a marked tendency to recur and a high morbidity and mortality rate in immunosuppressed patients. Treatment is usually prolonged and an associated antibiotic treatment is preferred for severe disease. Although sulfonamides in combination with other antibiotics are still the treatment of choice, other associations such as imipenem plus amikacin are preferred in some centers. Linezolid is a useful alternative therapeutic agent due to its oral availability and activity against most of the isolates studied. Twenty-eight cases of nocardiosis were diagnosed at our center between January 1989 and April 2009. We report the epidemiologic characteristics of Nocardia spp. observed in our institution and discuss the risk factors, clinical features, diagnosis, and management of the disease.

Pulmonary nocardiosis developed in a hematopoietic stem cell transplant recipient with bronchiolitis obliterans

The chronic graft-versus-host disease often requires unceasing immunosuppressive therapy (IST), which increases a risk of infectious complications in hematopoietic stem cell transplantation (HSCT) recipients. We report an adult T-cell leukemia/lymphoma case who developed pulmonary nocardiosis, a rare pulmonary complication, after allogeneic HSCT despite administration of the prophylactic trimethoprim-sulfamethoxazole (TMP/STX). The inhaled corticosteroid in addition to systemic IST had been started for bronchiolitis obliterance 4 months prior to nocardiosis development. The patient was successfully treated with an increased dose of TMP/STX combined with meropenem. Transplantation physicians should keep this rare pulmonary complication in mind during sustained IST.

Nocardia pseudobrasiliensis as an emerging cause of opportunistic infection after allogeneic hematopoietic stem cell transplantation

We report the case of a 55-year-old man who exhibited a nodular pneumonia 4 months after an allogeneic hematopoietic stem cell transplantation. Culture of the bronchoalveolar lavage fluid revealed Nocardia pseudobrasiliensis. This recently described carbapenem-resistant species should be included in the differential diagnosis of fungal infection in this setting.

Nocardiosis at the turn of the century

Nocardia species is an uncommon pathogen that affects both immunosuppressed and immunocompetent patients. The clinical and microbiologic spectrum of nocardiosis has changed recently due to the widespread use of cotrimoxazole prophylaxis, the emergence of new types of immunosuppressed patients, and the improved identification of isolates using molecular techniques. Nocardia asteroides was traditionally considered the predominant organism, and prophylaxis with cotrimoxazole was considered almost universally protective. We conducted the current study to determine the incidence of nocardiosis and its microbiologic and clinical characteristics in a general hospital over the last 12 years. We reviewed the clinical records of all patients in whom Nocardia species was isolated from clinical specimens between 1995 and 2006. Nocardia isolates were identified by standard procedures and by 5' end 16S rRNA gene polymerase chain reaction (PCR) and sequencing. Susceptibility to cotrimoxazole, minocycline, imipenem, linezolid, and amikacin was determined by the broth microdilution method following the guidelines of the Clinical and Laboratory Standards Institute.The incidence of Nocardia infections did not increase significantly during the study period (0.39/100,000 inhabitants in 1995-1998 and 0.55/100,000 inhabitants in 2003-2006). Nocardia was recovered from 43 patients. Six were considered to be colonized. The colonizing species were N. farcinica, N. nova, and N. asteroides. All colonized patients had severe underlying pulmonary conditions and were treated with antimicrobials (6 patients) or corticosteroids (4 patients). Invasive nocardiosis was diagnosed in 37 patients (86.5% were men, and their mean age was 55.8 +/- 17.3 yr). The most common underlying condition in our institution was human immunodeficiency virus (HIV) infection (10 patients; 27%), followed by chronic obstructive pulmonary disease (8 patients; 21.6%), autoimmune diseases (8 patients; 21.6%), solid organ transplantation (7 patients; 18.9%), and cancer (4 patients; 10.8%). The most important risk factor for nocardiosis was corticosteroid administration (23 patients; 62.2%). Nocardiosis affected the lungs in 26 cases (70.3%), the skin in 3 cases (8.1%), and the central nervous system in 2 cases (5.4%). It was disseminated in 5 cases (13.5%) and caused otomastoiditis in 1 (2.7%). The species identified were N. cyriacigeorgica (32.4%), N. farcinica (24.3%), N. otitidiscaviarum (10.8%), N. veterana (8.1%), N. nova (5.4%), N. abscessus (5.4%), N. asiatica (2.7%), N. beijingensis (2.7%), N. brasiliensis (2.7%), N. carnea (2.7%), and Nocardia species (2.7%).Linezolid and amikacin were uniformly active against all the isolates, whereas 29.7% of isolates showed intermediate susceptibility to minocycline (minimum inhibitory concentration = 2 mg/L), 10.8% were resistant to cotrimoxazole, and 5.4% were resistant to imipenem. Nocardiosis occurred while the patients were on cotrimoxazole prophylaxis in 8 cases (21.6%). The strains isolated from these patients were susceptible to cotrimoxazole in 5 cases (62.5%) and resistant in 3 (37.5%). Overall, 13 patients died (35.1%); related mortality was 21.6% (8 patients). We conclude that HIV infection has become the most common underlying condition for invasive nocardiosis in our institution, followed by chronic lung disease. Previous use of corticosteroids was the main risk factor and was present in more than half the patients. New species of Nocardia have been identified, and administration of cotrimoxazole prophylaxis should no longer be considered highly reliable protection against nocardiosis. Larger studies of nocardiosis are required to better identify risk factors associated with mortality, and alternative and more effective methods of prevention must be developed.

Nocardia exalbida brain abscess in a patient with follicular lymphoma

Nocardial brain abscess is a rare but severe complication in patients with malignancy. Nocardia exalbida was isolated in Japan and characterized within the genus Nocardia. We present the first report of N. exalbida brain abscess in a 63-year-old male patient with follicular lymphoma. He developed abnormal neurological findings during follicular lymphoma treatment, brain CT revealed ring-enhancing, multiloculated lesions, and N. exalbida was detected by aspiration of the lesion. He was successfully treated with trimethoprime-sulfamethoxazole (TMP-SMX) and meropenem without craniotomy or repeat aspirations. It should be noted that such an infection can occur in patients treated with conventional chemotherapy against malignant lymphoma.

Frequent exacerbation of pulmonary nocardiosis during maintenance antibiotic therapies in a hematopoietic stem cell transplant recipient

We describe a rare case of recurrent pulmonary nocardiosis (PN) in a hematopoietic stem cell transplant recipient. The patient developed Nocardia farcinica infection while receiving corticosteroid and cyclosporine for the treatment of bronchiolitis obliterans, probably due to chronic graft-versus-host disease (cGVHD). The patient responded well to the initial treatment with meropenem, but PN recurred 3 times during oral maintenance therapies using different antibiotics, which were chosen on the basis of the results of in vitro susceptibility testing against N farcinica Minocycline, amoxicillin/clavulanate, and levofloxacin were not effective as oral maintenance therapies. Frequent exacerbation of PN was considered to have resulted from the low blood concentration of these antibiotics, and decreased gastrointestinal absorption, probably due to cGVHD, might have been the underlying problem.

Pulmonary nocardiosis: risk factors and outcomes

BACKGROUND AND OBJECTIVES

Pulmonary nocardiosis (PN) is an infrequent but severe infection caused by Nocardia spp., which can behave either as opportunistic or primary pathogens. The present study identifies the risk factors for PN, clinical symptoms and radiographic features and the factors that affect its prognosis.

METHODS

An observational study of all the patients diagnosed with PN over a 13-year period at the authors' institution.

RESULTS

Thirty-one adult patients were identified with PN, 11 of whom had disseminated nocardiosis. The predisposing conditions were COPD (23%), transplantation (29%), HIV infection (19%), alcoholism (6.5%) and treatment with steroids (64.5%). Respiratory tract sampling using non-invasive techniques had a diagnostic yield of 77%, while specimens from invasive methods had a yield of 47%. Mean time to diagnosis was 42 days. Dissemination to the central nervous system was related to alcoholism. The mortality rates were 41% for PN and 64% for disseminated nocardiosis; when Nocardia disseminated to the central nervous system, the mortality was 100%.

CONCLUSION

Specific risk factors were found in 94% of patients, with the most common being corticosteroid treatment and immunosuppressive therapy. The time to reach diagnosis and to prescribe specific treatment was considerable and mandatory assessment for nocardia in high-risk patients is required. The mortality rate of PN is high and early diagnosis and treatment are needed. Medications other than co-trimoxazole may be required.

Pulmonary Nocardia and Aspergillus co-infection in a patient with chronic graft-versus-host disease

Immunosuppression and chronic graft-versus-host disease (GVHD) are major risk factors for the development of invasive pulmonary aspergillosis in bone marrow transplant patients. Although nocardial infections are well described in hematopoietic stem cell transplantation (HSCT) recipients, little information is available about the incidence of nocardiosis in patients with chronic GVHD after HSCT. Coexistence of invasive pulmonary aspergillosis and nocardiosis following non-myeloablative HSCT has not been reported previously. With the increasing use of pentostatin in the treatment of chronic GVHD in future and other nucleoside analogues as preparative regimens in patients undergoing reduced-intensity conditioning transplantation, the possibility of co-infection with rare organisms should be kept in mind while assessing at-risk patients.

Complications pulmonaires précoces des allogreffes de cellules souches hématopoïétiques

INTRODUCTION

Pneumonia is one of the main causes of mortality following allogenic stem cell transplantation, especially in the first months after the transplant has been performed.

STATE OF THE ART

Pneumonia is the most common infection occurring after transplant and the infection with the highest mortality. Following the classical, myeloablative approach to transplant, two thirds of the pneumonias that occur are of infectious origin. Their causes roughly follow the timing of the immune reconstitution, and may depend on the type of transplant, the match between donor and recipient, and, overall, the occurrence of graft-versus-host disease. Most bacterial pneumonias occur during the initial neutropenic phase. The 2nd and 3rd month post transplant are mainly complicated by viral pneumonia, especially respiratory virus and adenovirus pneumonia in deeply immunosuppressed patients. Preemptive and prophylactic strategies have considerably reduced the incidence of cytomegalovirus pneumonia. Pneumonia due to encapsulated bacteria, such as Haemophilus influenzae and Streptococcus pneumoniae, usually considered to be late infections, may actually be observed from the second month post-transplant.

PERSPECTIVES

The increasing use of reduced-intensity conditioning regimens has modified the time course of the main adverse events following transplantation, including the timing of the infectious pneumonias. The pneumonias that are specifically related to allogenic transplant are idiopathic interstitial pneumonia, bronchiolitis obliterans, and bronchiolitis obliterans organizing pneumonia, which are all considered to be pulmonary manifestations of graft-versus-host disease, and treated as such. Prophylaxis for many of these infectious pneumonias (i.e., P jiroveci, S pneumoniae, toxoplasmosis) are well standardized.

CONCLUSIONS

Much remains to be done to decrease the incidence of pneumonia in these patients and to understand their mechanisms.

Nocardia cyriacigeorgica septicemia

We report two cases of Nocardia cyriacigeorgica septicemia and disseminated infection in the setting of profound immunodeficiency. In both instances, diagnosis was rapidly facilitated by 16S rRNA gene sequencing of blood culture isolates. These constitute the first confirmed reports of Nocardia cyriacigeorgica bloodstream infection in humans.