Nocardia infection in kidney transplant recipients: case report and analysis of 66 published cases

Solid organ transplant-related central nervous system infections

PURPOSE OF REVIEW

Central nervous system (CNS) infections in solid organ transplant (SOT) recipients may present atypical or nonspecific symptoms. Due to a wider range of infectious agents compared with immunocompetent hosts, diagnosis is challenging. This review categorizes CNS infections in SOT recipients by cause.

RECENT FINDINGS

New studies have reported new data on the epidemiology and the risk factors associated with each specific pathogen described in this review. Additionally, we included the treatment recommendations.

SUMMARY

The latest findings give us an insight into the different pathogens causing infectious neurologic complications in SOT recipients.

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.

Nocardiosis in renal transplant patients

Renal transplant patients are immunosuppressed and are at increased risk of opportunistic infections, including Nocardia infection. In renal transplant patients, information on the incidence and risk factors associated with nocardiosis is limited. To address the incidence and risk factors associated with nocardiosis in a large renal transplant population, we used the US Renal Data System (USRDS). Sequelae of allograft failure or rejection after infection were also examined. Demographics, clinical risk factors, Nocardia diagnosis, and allograft failure following Nocardia infection were queried in USRDS renal transplant patients using International Classification of Diseases, Ninth Revision (ICD-9) codes in billing claims and Centers for Medicare and Medicaid Services Form 2728. Generalized linear models were used to determine the risk factors associated with nocardiosis, and Cox proportional hazards models were used to examine the association of risk factors with graft failure among patients with Nocardia infection. Of 203,233 renal transplant recipients identified from 2001 to 2011, 657 (0.32%) were diagnosed with Nocardia infection. Pneumonia was the most frequent presentation (15.2%), followed by brain abscess (8.4%). Numerous factors associated with increased Nocardia infection included age >65 years (OR=2.10, 95% CI 1.71 to 2.59), history of transplant failure (OR=1.28, CI 1.02 to 1.60) or history of rejection (OR=4.83, CI 4.08 to 5.72), receipt of a deceased donor transplant (OR=1.23, CI 1.03 to 1.46), and treatment with basiliximab (OR=1.25, CI 1.00 to 1.55), cyclosporine (OR=1.30, CI 1.03 to 1.65), tacrolimus (OR=2.45, CI 2.00 to 3.00), or thymoglobulin (OR=1.89, CI 1.59 to 2.25). In patients with nocardiosis administration of antithymocyte globulin (HR=2.76), chronic obstructive pulmonary disease (HR=2.47), and presentation of Nocardia infection with brain abscess (HR=1.85) were associated with an increased risk of graft failure. This study provides new information to enhance early recognition and targeted treatment of nocardiosis in renal transplant patients.

Clinical Nocardia species: Identification, clinical characteristics, and antimicrobial susceptibility in Shandong, China

Nocardia is a pathogen responsible for a variety of clinical infections. Here, we aimed to investigate the species distribution, clinical manifestations, and antimicrobial susceptibility of Nocardia species over 3 years in two tertiary general hospitals in China. In this retrospective study, a total of 27 Nocardia species were isolated from 27 individuals between January 2017 and December 2019. Nocardia isolates were identified to species level by mass spectrometry and 16S rRNA PCR sequencing. Clinical data were collected from medical records. Antimicrobial susceptibility was determined by the standard Broth microdilution method. The 27 patients with Nocardia infection included 12 males and 15 females with a mean age of 60.11 years. Among 27 Nocardia isolates, 7 species were identified, with the most common species being Nocardia otitidiscaviarum (40.7%). The antimicrobial susceptibility profiles varied between different Nocardia species. Notably, all Nocardia isolates were linezolid susceptible. The majority of Nocardia isolates were collected from a department of respiratory medicine (55.56%) and sputum specimen (44.44%). Pulmonary region was the most involved body site (70.37%) followed by skin (7.4%) and pleural cavity (7.4%). Most patients with Nocardia infection needed combination antibiotic therapy. Two deaths were reported during the treatment period and 24 patients achieved improvement after antibiotic therapy. The clinical manifestations of Nocardia infection and antimicrobial susceptibility profiles varied with diverse Nocardia species. Thus, the accurate identification of these species is crucial for the diagnosis and the selection of antibiotic treatment.

A Rare Case of Drug-Resistant Nocardia transvalensis Infection in a Renal Transplant Patient

Nocardia transvalensis is a rare species of Nocardia and is known to be a drug-resistant organism. Multiple cases have been reported of Nocardia species causing opportunistic infections in immunocompromised hosts. To our knowledge, we report the first case of successfully treated drug-resistant Nocardia transvalensis causing pulmonary nocardiosis in a renal transplant patient. Our case validates the importance of prompt identification of Nocardia species and their drug sensitivities to improve clinical outcomes and reduce mortality.

Nocardia bacteremia: A single-center retrospective review and a systematic review of the literature

OBJECTIVES

Nocardia bacteremia is a rare but severe disease associated with high mortality. This systematic review is the largest and most comprehensive review performed over the past 20 years.

METHODS

A single-center retrospective review of Nocardia bacteremia was performed using hospital microbiology records from January 1, 2010 to December 31, 2017. A systematic literature review was also performed to identify cases of Nocardia bacteremia described in the NCBI PubMed database in English between January 1, 1999 and December 31, 2018.

RESULTS

Four new cases of Nocardia bacteremia are described. The systematic review identified 134 cases with sufficient information available for analysis. Of the total 138 cases, the median age was 58 years (interquartile range (IQR) 44-69 years) and 70% were male. Eighty-one percent were immunocompromised (corticosteroid use (49%), hematological malignancy (20%), solid organ transplant (20%), solid organ malignancy (19%), and hematopoietic stem cell transplantation (15%)) and 29% had endovascular devices. Pulmonary infection was the most common concurrent site of clinical disease (67%). The median incubation time to the detection of Nocardia bacteremia was 4 days (IQR 3-6 days). Blood cultures were the only positive microbiological specimen in 38% of cases. The median total duration of treatment was 75 days (IQR 25-182 days). Thirty-day all-cause mortality was 28% and overall all-cause mortality was 40%.

CONCLUSIONS

Nocardia bacteremia is most frequently identified in immunocompromised patients and those with intravascular devices. Although rare, it represents a serious infection with high associated overall mortality.

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.

Management of Infection in Patients With Kidney Transplant

With the pervasive nature of chronic kidney disease, kidney transplantation is likely to continue to increase in the coming years. There are many infectious risks related to kidney transplant, including reactivation of latent infections, surgical complications, infectious risks related to immunosuppression, and nosocomial and community-acquired infections. These are described classically via timeline with early infections (first month), middle (1 to 6 months), and late (after 6 months). Kidney transplant patients may suffer from infections secondary to a vast array of organisms, including bacteria, fungi, and viruses. Certain infections, particularly viral infections such as cytomegalovirus, Epstein-Barr virus, and BK virus, may portend acute and chronic implications of the infection and its subsequent impact on graft function. Critical care physicians and nephrologists caring for patients with a renal transplant must understand the broad array of possible infections, atypical presentations, and nuanced implications for appropriate evaluation and subsequent therapy, combined with the need for possible prophylaxis and/or suppression. Multidisciplinary teams, including transplant physicians and infectious diseases physicians, are encouraged strongly.

Respiratory Tract Infections: Sinusitis, Bronchitis, and Pneumonia

Solid organ and hematopoietic stem cell transplant recipients are at increased risk of upper and lower respiratory tract infections. While these infections are frequently encountered in the general population, the spectrum of their clinical presentation including morbidity and mortality is increased in patients undergoing transplantation procedures. Impaired innate and adaptive immunity, potential anatomical abnormalities resulting from extensive surgical procedures, presences of indwelling medical devices, and increased healthcare exposure put transplant recipients at particularly high risk for respiratory tract disease. Infections of the respiratory tract can be divided into those affecting the paranasal sinuses, the upper airways such as bronchitis and tracheobronchitis, and the lower airways like pneumonia. Each of these clinical syndromes can further be classified based on their chronicity, acute vs. chronic; their setting, community vs. nosocomial; and the etiology such as bacteria, viruses, fungi, and rarely parasites. It is also important to realize that such immunologically vulnerable patients are at risk for polymicrobial infection that may present concurrently or in a sequential, consecutive fashion. This chapter reviews the common respiratory tract infections affecting transplant recipients with particular attention directed toward epidemiological risk factors, clinical presentations, diagnostic strategies, and common pathogens. Specific causes of opportunistic pneumonias are also reviewed.

Sporotrichoid Skin Infection Caused by Nocardia brasiliensis in a Kidney Transplant Patient

Prompt and accurate diagnosis of Nocardia skin infections is important in immunocompromised hosts, especially transplant patients. The sporotrichoid form, which is otherwise known as the lymphocutaneous form of Nocardia skin involvement, can mimic other conditions, including those caused by fungi, mycobacteria, spirochetes, parasites and other bacteria. Delayed or inaccurate diagnosis and treatment of Nocardia skin infections in transplant patients could lead to dissemination of disease and other poor outcomes. Nocardia brasiliensis is a rare cause of lymphocutaneous nocardiosis in solid organ transplant patients with only two other cases reported to our knowledge. This case describes a middle-aged man, who presented 16 years post kidney transplant. He developed a sporotrichoid lesion on his upper extremity one week after gardening. Ultrasound showed a 35-cm abscess tract on his forearm, which was subsequently drained. Nocardia brasiliensis was isolated from pus culture and he was treated successfully with amoxicillin/clavulanate for 6 months. A review of the relevant literature is included.

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.

Bacterial pneumonia in kidney transplant recipients

Bacterial pathogens are the most frequent cause of pneumonia after transplantation. Early after transplantation, recipients are at higher risk for nosocomial infections. The most commonly encountered pathogens during this period are gram-negative bacilli (Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa …), but gram-positive coccus such as Staphylococcus aureus or Streptococcus pneumoniae and anaerobic bacteria can also be found. Empirical antibiotic therapy should be guided by previous colonisation of the recipient and bacterial resistance pattern in the hospital. Six months after transplantation, pneumonias are mostly due to community-acquired bacteria (S. pneumonia, H. influenza, Mycoplasma, Chlamydia and others). Opportunistic pathogens take advantage of the state of immunosuppression which is usually highest from one to six months after transplantation. During this period, but also occurring many years later in the setting of a chronically depressed immune system, bacterial pathogens with low intrinsic virulence can cause pneumonia. The diagnosis of pneumonia caused by opportunistic pathogens can be challenging. The delay in diagnosis preventing the early instauration of adequate treatment in kidney transplant recipients with a depressed immune system, frequently coupled with co-morbid conditions and a state of frailty, will affect prognosis and outcome, increasing morbidity and mortality. This review will focus on the most common opportunistic bacterial pathogens causing pneumonia in kidney transplant recipients: Legionella, Nocardia, Mycobacterium tuberculosis/nontuberculous, and Rhodococcus. Recognition of their specificities in the setting of immunosuppression will allow early diagnosis, crucial for initiation of effective therapy and successful outcome. Interactions with immunosuppressive therapy should be considered as well as reducing immunosuppression if necessary.

Nocardia spp. Pneumonia in a Solid Organ Recipient: Role of Linezolid

We describe a rare infection with Nocardia spp. (N. pseudobrasiliensis species identification based on high-performance liquid chromatography analysis) in a 68-year-old renal transplant recipient. He presented with pneumonia complicated by hypoxic respiratory failure. He was allergic to sulphonamides. He was initially successfully treated with linezolid. However, he suffered severe sensory neuropathy after 4 months of therapy, necessitating linezolid cessation and completion of treatment with azithromycin. He had clinical and radiological resolution of his pneumonia and was disease free at subsequent follow-up 4 years later. This case highlights the need for alternative therapies for nocardiosis for patients that cannot be treated with sulphonamides due to allergies or/and infection with multidrug-resistant pathogens. It also illustrates the treatment limiting side effects of long-term therapy with linezolid.

Syndrome of Inappropriate Antidiuretic Hormone Secretion Complicating Systemic Nocardiosis in a Renal Transplant Recipient: A Case Report

BACKGROUND

Infection by Nocardia species is an uncommon cause of severe clinical syndromes, particularly in immunocompromised patients, and solid-organ transplantation is the most common underlying condition. The syndrome of inappropriate antidiuretic hormone secretion (SIADH) has been described thus far in lung and stem cell transplants with systemic nocardiosis.

CASE REPORT

We report the first case of SIADH in a female elderly renal transplant recipient diagnosed with systemic nocardiosis 2 years after transplantation. The SIADH was managed appropriately, and her immunosuppressive regimen remained unchanged but was adjusted at a lower level. The systemic Nocardia infection was successfully treated with intravenous administration of trimethoprim-sulfamethoxazole and imipenem for 2 weeks followed by oral trimethoprim-sulfamethoxazole for a total of 12 months.

CONCLUSIONS

The SIADH syndrome is a recognizable complication of Nocardia infection in renal transplant recipients. Prompt identification along with proper management and prolonged antimicrobial treatment are essential to improve patients' outcome.

Nocardiosis in ectopic ACTH syndrome: A case report and review of 11 cases from the literature

Ectopic adrenocorticotropic hormone (ACTH) syndrome (EAS) associated with nocardiosis is rare, and little information is available regarding its clinical characteristics. In this study, the case of a 35-year-old male patient who showed significant cushingoid features and had a cough with yellow phlegm for 1 month is described. Pulmonary computed tomography (CT) scanning and ¹⁸F-fluorodeoxyglucose positron emission tomography combined with CT identified two different lesions in the mediastinum and pulmonary region, respectively. The lesion in the mediastinum was finally diagnosed as an ACTH-secreting mediastinal paraganglioma via biopsy. The sputum culture confirmed pulmonary nocardiosis. The patient was effectively treated with complete tumor resection following the treatment of nocardiosis using trimethoprim-sulfamethoxazole. Following the present case, 11 additional cases of nocardiosis in EAS were identified in the literature and their clinical characteristics were compared and evaluated. It may be concluded that, although Nocardia remains a rare opportunistic infection pathogen in EAS, it is necessary to consider nocardiosis as a diagnosis for patients with pulmonary imaging findings of cavity, consolidation or nodule, particularly when there are brain and extra-pulmonary lesions as well as a poor response to regular treatment.

Different faces of Nocardia infection in renal transplant recipients

AIM

Nocardia infections are an uncommon but important cause of morbidity and mortality in renal transplant recipients. The present study was carried out to determine the spectrum of Nocardia infections in a renal transplant centre in Australia.

METHODS

A retrospective chart analysis of all renal transplants performed from 2008 to 2014 was conducted to identify cases of culture proven Nocardia infection. The clinical course for each patient with nocardiosis was examined.

RESULTS

Four of the 543 renal transplants patients developed Nocardia infection within 2 to 13 months post-transplant. All patients were judged at high immunological risk of rejection pre-transplant and had received multiple sessions of plasmaphoeresis and intravenous immunoglobulin before the onset of the infection. Two patients presented with pulmonary nocardiosis and two with cerebral abscesses. One case of pulmonary nocardiosis was complicated by pulmonary aspergillosis and the other by cytomegalovirus pneumonia. All four patients improved with combination antibiotic therapy guided by drug susceptibility testing. At the time of Nocardia infection all four patients were receiving primary prophylaxis with trimethoprim/sulphamethoxazole (TMP/SMX) 160/800 mg, twice weekly.

CONCLUSION

Plasmaphoeresis may be risk factor for Nocardia infection and need further study. Nocardia infection may coexist with other opportunistic infections. Identification of the Nocardia species and drug susceptibility testing is essential in guiding the effective management of patients with Nocardia. Intermittent TMP-SMX (one double strength tablet, twice a week) appears insufficient to prevent Nocardia infection in renal transplant recipients.

The Critically Ill Kidney Transplant Recipient: A Narrative Review

Kidney transplantation is the most common solid organ transplantation performed worldwide. Up to 6% of kidney transplant recipients experience a life-threatening complication that requires ICU admission, chiefly in the late posttransplantation period (≥ 6 months). Acute respiratory failure and septic shock are the main reasons for ICU admission. Cardiac pulmonary edema, bacterial pneumonia, acute graft pyelonephritis, and bloodstream infections account for the vast majority of diagnoses in the ICU. Pneumocystis jirovecii pneumonia is the most common opportunistic infection, and one-half of the patients so infected require mechanical ventilation. The incidence of cytomegalovirus visceral infections in the era of preemptive therapy has dramatically decreased. Drug-related neutropenia, sirolimus-related pneumonitis, and posterior reversible encephalopathy syndrome are among the most common immunosuppression-associated toxic effects. Importantly, the impact of critical illness on graft function is worrisome. Throughout the ICU stay, acute kidney injury is common, and about 40% of the recipients require renal replacement therapy. One-half of the patients are discharged alive and free from dialysis. Hospital mortality can reach 30% and correlates with acute illness severity and reason for ICU admission. Transplant characteristics are not predictors of short-term survival. Graft survival depends on pre-ICU graft function, disease severity, and renal toxicity of ICU investigations and treatments.

Nocardiosis presenting as a lung mass in a kidney transplant recipient

Nocardiosis is a potentially life-threatening disease in renal transplant recipients. It is an uncommon infection with high lethality if left untreated. We report a case of a 67 year-old kidney transplant recipient who developed pulmonary nocardiosis and presented with pleural effusion along with an underlying lung mass, which was successfully treated with trimethoprim-sulphamethoxazole in conjunction with a reduction in immunosuppressive therapy. Five months later, graft function remains stable with complete regression of radiological abnormalities and absence of symptoms. Nocardiosis should be suspected in the presence of pulmonary symptoms in a transplant patient with unusual radiological presentation.

Diversity and frequency of Nocardia spp. in the soil of Isfahan province, Iran

OBJECTIVE

To isolate and identify Nocardia spp. from soil in different regions of Isfahan province in the center of Iran.

METHODS

This study was conducted in 32 districts (16 cities and 16 villages) in Isfahan province during two years. A total of 800 soil samples from these regions were studied by using kanamycin. The isolated Nocardia species were examined by gram and acid-fast staining and were identified biochemically and morphologically. The frequency and distribution of Nocardia spp. were determined in relation to different factors such as soil pH and temperate climate.

RESULTS

From 153 (19.1%) Nocardia isolates identified, Nocardia asteroids (N. asteroids) complex (45.5%) and Nocardia brasiliensis (N. brasiliensis) (24.7%) were the most frequently isolated species, followed by Nocardia otitidiscaviarum (2.2%), Nocardiopsis dassonvillei, Actinomadura actinomadura (each 1.7%) and Nocardia transvalensis (1.1%) and also unknown spp. (23.0%). In this study, most species (54.4%) of Nocardia, especially N. asteroides complex were isolated from soils with pH: 7.01-8, whereas in pH: 8.01-9 more N. brasiliensis was isolated. The most Nocardia spp. was detected from regions with semi-nomadic and temperate climate (41.1%).

CONCLUSIONS

N. asteroids complex is more prevalent in Isfahan province and soil can be a potential source of nocardiosis infections. It is to be considering that climate and soil pH are involved in the frequency and diversity of aerobic Actinomycetes.

Role of therapeutic drug monitoring in pulmonary infections: use and potential for expanded use of dried blood spot samples

Respiratory tract infections are among the most common infections in men. We reviewed literature to document their pharmacological treatments, and the extent to which therapeutic drug monitoring (TDM) is needed during treatment. We subsequently examined potential use of dried blood spots as sample procedure for TDM. TDM was found to be an important component of clinical care for many (but not all) pulmonary infections. For gentamicin, linezolid, voriconazole and posaconazole dried blood spot methods and their use in TDM were already evident in literature. For glycopeptides, β-lactam antibiotics and fluoroquinolones it was determined that development of a dried blood spot (DBS) method could be useful. This review identifies specific antibiotics for which development of DBS methods could support the optimization of treatment of pulmonary infections.

Risk of infectious diseases and cutaneous tumours in solid organ recipients: A meta-analysis of literature

AIM: To compare the risk of cutaneous infections and tumours in kidney transplant recipients with data recently published about this topic.

METHODS: In the present work, we evaluated the incidence of bacterial, fungal and viral cutaneous infectious diseases and the development of skin cancers in a cohort of 436 patients who underwent a renal transplantation. The median age at transplantation of our patients was 50 years and the median duration of the immunosuppression was of 7.2 years. Data obtained from our cohort were compared with those obtained by a systematic review of the literature of the last 20 years about the same topic.

RESULTS: Infectious diseases were the most frequent dermatological disorders that were diagnosed after transplantation, affecting about the 16.5% of patients. Herpes virus reactivation occurs in about the 35% of patients and is more common within 6 mo from transplantation, whereas when the immunosuppression is reduced, skin infections are mainly represented by Human Papilloma Virus infections and localized mycosis, such as pityriasis versicolor and superficial candidiasis. Bacterial infections were relatively rare and occur mainly in the first months after transplantation. The cumulative risk to develop skin cancer enhance significantly over the time, as consequence of long-term immunosuppressive regiments. Endogenous and exogenous risk factors, as well as the schedule of immunosuppression can play a role and justify the different incidence of skin cancer in the various series.

CONCLUSION: Skin infections and cancer, commonly diagnosed in transplanted patients, impact on survival and life-quality, justifying the realization of follow-up programs for the early diagnosis and treatment.

First case of disseminated infection with Nocardia cerradoensis in a human

Here we report in a human, a renal transplant patient, the first disseminated infection with Nocardia cerradoensis, isolated after a brain biopsy. Species identification was based on 16S rRNA, gyrB, and hsp65 gene analyses. Antibiotic treatment was successful by combining carbapenems and aminoglycosides and then switching to oral trimethoprim-sulfamethoxazole.

Clinical findings of 40 patients with nocardiosis: A retrospective analysis in a tertiary hospital

To the best of our knowledge, no Chinese case studies concerning Nocardia infection have been published to date. Therefore, the present study aimed to retrospectively evaluate the risk factors, clinical features, imaging results, laboratory abnormalities, treatments and outcomes of nocardiosis in a Chinese tertiary hospital. Data collected from patients with laboratory-confirmed nocardiosis were retrospectively analyzed. A total of 40 patients who had a positive culture of Nocardia were included. The median time between the onset of symptoms and diagnosis was 42 days. Underlying diseases were identified in 72.5% of the patients of which diabetes was the most common (32.5%). The most important risk factor was corticosteroid administration. Fever and cough were common clinical symptoms. The pleuropulmonary (85%) were the most frequently involved sites and the disseminated disease rate was 30.0%. Frequent chest computed tomography scans revealed the presence of airspace opacities, nodules and masses, in addition to cavitary lesions that were particularly common among the study group. Brain images revealed lesions associated with abscesses. The majority of the patients (71.1%) were treated with trimethoprim sulfamethoxazole alone or in combination with other drugs. The in-hospital mortality rate was 15.0%. Disseminated disease, immunocompromised patients, an older age, brain involvement and concomitant infections were associated with a poor prognosis. Nocardiosis is an uncommon but emerging disease. The present study reports the first case series on nocardiosis from China and provides important information on the clinical features and risk factors of nocardiosis. Early recognition of the disease and the initiation of appropriate treatment are essential for a good prognosis.

Infectious Complications of Transplantation

Post-transplant infection is a common cause of graft deterioration, morbidity and mortality. It is also responsible for delayed discharge, multiple, often prolonged admissions and thus a significant clinical challenge. Infections can be donor derived, pre-existing in the recipient, nosocomial and opportunistic. For each of these categories, it is often possible to significantly reduce hazard and thus the adverse consequences by first identifying patients at high risk. As always, clinical vigilance is vital, but equally important is the establishment of robust clinical systems for prevention, screening and rapid treatment.

Molecular identification of nocardia isolates from clinical samples and an overview of human nocardiosis in Brazil

BACKGROUND

Nocardia sp. causes a variety of clinical presentations. The incidence of nocardiosis varies geographically according to several factors, such as the prevalence of HIV infections, transplants, neoplastic and rheumatic diseases, as well as climate, socio-economic conditions and laboratory procedures for Nocardia detection and identification. In Brazil the paucity of clinical reports of Nocardia infections suggests that this genus may be underestimated as a cause of human diseases and/or either neglected or misidentified in laboratory specimens. Accurate identification of Nocardia species has become increasingly important for clinical and epidemiological investigations. In this study, seven clinical Nocardia isolates were identified by multilocus sequence analysis (MLSA) and their antimicrobial susceptibility was also determined. Most Nocardia isolates were associated to pulmonary disease.

METHODOLOGY/PRINCIPAL FINDINGS

The majority of Brazilian human isolates in cases reported in literature were identified as Nocardia sp. Molecular characterization was used for species identification of Nocardia nova, Nocardia cyriacigeorgica, Nocardia asiatica and Nocardia exalbida/gamkensis. Data indicated that molecular analysis provided a different Nocardia speciation than the initial biochemical identification for most Brazilian isolates. All Nocardia isolates showed susceptibility to trimethoprim-sulfamethoxazole, the antimicrobial of choice in the treatment nocardiosis. N. nova isolated from different clinical specimens from one patient showed identical antimicrobial susceptibility patterns and two distinct clones.

CONCLUSIONS/SIGNIFICANCE

Although Brazil is the world's fifth-largest country in terms of land mass and population, pulmonary, extrapulmonary and systemic forms of nocardiosis were reported in only 6 of the 26 Brazilian states from 1970 to 2013. A least 33.8% of these 46 cases of nocardiosis proved fatal. Interestingly, coinfection by two clones may occur in patients presenting nocardiosis. Nocardia infection may be more common throughout the Brazilian territory and in other developing tropical countries than is currently recognized and MLSA should be used more extensively as an effective method for Nocardia identification.

Primary cutaneous nocardiosis caused by Nocardia nova in a kidney transplant recipient

Nocardia nova is a rare aetiological pathogen for cutaneous nocardiosis. To the best of our knowledge, this is the first case of N. nova primary cutaneous infection in a kidney transplant recipient. Identification was performed using 16S rRNA and secA1 gene sequence analyses. The patient was not treated successfully by antibiotics alone. Surgical debridement was required for successful treatment.

Disseminated Nocardia infection in a renal transplant patient: the pitfalls of diagnosis and management

This case report describes the progress of an immunosuppressed renal transplant patient who presented with signs and symptoms of community acquired pneumonia. He did not respond to conventional therapy and underwent further investigation. Definitive diagnosis proved challenging. On the basis of multiple investigation results he was treated variously for bacterial, viral and tuberculous infections. At one point it was thought pulmonary malignancy was likely. After excision of a subcutaneous nodule, microscopy and culture confirmed diagnosis of disseminated Nocardia farcinica. This case demonstrates the difficulty in diagnosing this rare infection in immunocompromised patients, the problems posed by concomitant infection and the potential hazards of multiple drug interactions. On initiation of optimum antimicrobial therapy and with safe levels of immunosuppression our patient made full recovery without any loss in graft function.

Molecular identification and susceptibility pattern of clinical Nocardia species: Emergence of Nocardia crassostreae as an agent of invasive nocardiosis

BACKGROUND

Nocardia species are rare, opportunistic organisms that cause disease in both immunocompetent and immunocompromised individuals.

OBJECTIVE

To investigate the clinical presentations of various Nocardia infections based on the 16S ribosomal RNA gene of the isolate, as well as related risk factors and susceptibility patterns to antimicrobial agents.

METHODS

Thirteen patients with a diagnosis of nocardiosis were included in the present study. Seven Nocardia species were identified by 16S ribosomal RNA. Susceptibility testing was performed using six antimicrobial agents.

RESULTS

Five patients were immunocompromised, and eight were immunocompetent with predisposing factors including cystic fibrosis, tuberculosis and ophthalmic infections. Nocardia caused pulmonary infections in eight patients (61.5%), invasive systemic infections in three patients (23%) and local (ophthalmic) infections in two patients (15.4%). In the patients with pulmonary disease, nocardiosis was caused by six species (Nocardia cyriacigeorgica, Nocardia otitidiscaviarum, Nocardia farcinica, Nocardia carnea, Nocardia testacea and Nocardia asiatica). The seventh species identified in the present study was Nocardia crassostreae.

DISCUSSION

N crassostreae is a multidrug-resistant organism that was reported to be an emerging human pathogen causing invasive nocardiosis in a patient with non-Hodgkin's lymphoma. N farcinica was isolated from blood in a patient with breast cancer. None of the Nocardia isolates were resistant to linezolid. One N otitidiscaviarum isolate was a multidrug-resistant organism. All patients in the present study were treated with the appropriate antibiotics and their condition resolved without further sequelae.

CONCLUSIONS

The present study is the first report on N crassostreae as a human pathogen. The detection of multidrug-resistant species necessitate molecular identification and susceptibility testing, and should be performed for all Nocardia infections. Nocardiosis manifests various clinical features depending on the Nocardia species and underlying conditions.

Allergic broncho pulmonary aspergillosis complicated by nocardiosis

We describe a 70-year-old male with a history of diabetes mellitus, hypertension, and asthma who presented with increasing breathlessness for 5 months. He was diagnosed to have allergic bronchopulmonary aspergillosis (ABPA) by serological and radiographic criteria. He was treated with steroids and itraconazole. After initial improvement, he developed fever with cough and mucopurulent sputum. X-ray chest revealed multiple cavities with air fluid level. Patient was treated with antibiotics without any response. Sputum was negative for acid fast bacilli (AFB). Sputum culture for bacteria and fungus did not reveal any significant growth; however a delayed growth of Nocardia was noted on fungal plates. Modified Ziehl Nelsen stain was positive for AFB. Patient was treated with cotrimoxazole. We discuss the serological and radiological criteria of ABPA, presentation and treatment of nocardia pulmonary infection and other possible causes of necrotizing pneumonia in immunocompromised settings.