Bacteremic pneumonia caused by Nocardia veterana in an HIV-infected patient

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.

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 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.

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.

Pyogranulomatous pleuropneumonia caused by Nocardia asiatica in a dog coinfected with canine morbillivirus (canine distemper virus)

Nocardia asiatica causing pyogranulomatous pleuropneumonia is reported for the first time in a dog coinfected with canine morbillivirus (CM), diagnosed based on epidemiological, clinical, haematological, images, microbiological, histopathological, polymerase chain reaction and hsp65 gene sequencing findings. The immunosuppression of CM probably favoured the opportunistic behaviour of N. asiatica. Despite the therapeutic measures, the animal died, mainly due to respiratory distress. The association of methods to improve early diagnosis, therapy procedures and prognosis of canine nocardiosis is discussed, as well as the close relationship between pets and their owners, which may favour the transmission of pathogens such as Nocardia from pets‐to‐humans, which poses an emerging public health issue.

Nocardiosis from 1888 to 2017

The genus Nocardia is an aerobic bacterium, Gram-positive and catalase positive that is in Nocardiaceae family. This bacterium first described by Edmond Nocard in 1888 and is not in human commensal bacteria. To date, nocardiosis incidence is increasing due to increase population growth rate, increase in patients with immune disorder diseases and immunocompromised patients. We surveyed taxonomic position, isolation methods, phenotypic and molecular identification at the genus and species levels, antibiogram, treatment and epidemiology in the world from 1888 to 2017.

Fatal nocardiosis in a dog caused by multiresistant Nocardia veterana

Among pathogenic Nocardia species in humans and animals, infections caused by Nocardia (N.) veterana have rarely been described and so far, all non-human cases are linked to bovine mastitis in Brazil. The aim of this study was to identify the causative microorganism involved in the death of a three-month-old dog suffering from dyspnea and neurological deficits ante mortem. Pathomorphological investigation revealed (pyo-)granulomatous lesions in various organs. Bacteriological examination was performed and the respective bacteria were subjected to matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS), 16S rDNA sequencing, and antimicrobial susceptibility testing by broth microdilution. Gram-staining and colony morphology suggested the presence of an actinomycete which was identified as N. veterana by MALDI-TOF MS. This identification was confirmed by 16S rDNA sequence analysis. Distemper-associated immunosuppression may have played a role in the pathogenesis of systemic nocardiosis in this dog. Retrospective analysis of the antimicrobial susceptibility status showed that the N. veterana isolate was multiresistant and displayed high minimal inhibitory concentrations to all antimicrobial agents used for the dog's therapy. To the best of our knowledge, this is the first report of a systemic nocardiosis caused by N. veterana in a dog with a concurrent canine distemper virus infection.

Nocardia veterana: disseminated infection with urinary tract infection

Nocardia spp. are a group of aerobic actinomycetes widely distributed in soil, and associated with severe opportunistic infections, essentially pulmonary infections. We report the first case of disseminated infection associated with urinary tract infection caused by Nocardia veterana. The diagnosis was difficult; despite the presence of pulmonary nodules, the lung biopsies remained negative while only one aerobic blood culture and the urine culture were positive for N. veterana, identified after a 16S rDNA gene sequence analysis. Few cases of clinical importance due to N. veterana have been published since its characterization. The bacteriological diagnosis of nocardiosis can be difficult to establish because of the delayed growth and the specific techniques that are required. This case illustrates the necessity of performing specific investigations in immunocompromised patients who present with infectious disease because the severity of this infection requires early diagnosis and quick initiation of appropriate antibiotic therapy.

Other HIV-associated pneumonias

The incidence, mortality, and epidemiology of human immunodeficiency virus (HIV)-associated pulmonary infections have changed as a result of effective antiretroviral and prophylaxis antimicrobial therapy. The clinical presentation, radiographic abnormalities, and treatment of pneumonia from various uncommon pathogens in patients with AIDS can be different from those in immunocompetent patients. Advances in invasive and noninvasive testing and molecular biological techniques have improved the diagnosis and prognosis of pulmonary infections in patients infected with HIV. This review focuses on pulmonary infections from nontuberculosis mycobacteria, cytomegalovirus, fungi (aspergillosis, cryptococcosis, endemic fungi), and parasites (toxoplasmosis), and uncommon bacterial pneumonia (nocardiosis, rhodococcosis) in these patients.

First case report of Nocardia veterana causing nodular lymphangitis in an immunocompromised host

We report a unique case of ascending cutaneous lymphangitis in a 72-year-old immunocompromised man from which a newly described Nocardia species was isolated by 16S ribosomal gene sequencing. Treatment with trimethoprim-sulfamethoxazole resulted in successful resolution of symptoms. To the best of our knowledge, this is the first case report of N. veterana implicated in causing ascending cutaneous lymphangitis.

Nocardia veterana endogenous endophthalmitis in a cardiac transplant patient

Background

Endogenous endophthalmitis secondary to Nocardia species is extremely rare but often portends a poor visual prognosis often owing to the advanced nature of disease at presentation and delay in diagnosis. Patients who are systemically immunosuppressed are at greatest risk and early suspicion of the role of this organism in patients with acute panuveitis is paramount.

Findings

A 66-year-old cardiac transplant patient on oral prednisone, Myfortic, and tacrolimus developed unilateral panuveitis with a focal white subretinal and retinal lesion. His past medical history was notable for Aspergillus pneumonia and cytomegalovirus retinitis in the contralateral eye 12 months prior. Aqueous humor sampling for eubacterial, eufungal, and viral PCR testing, as well as vitreous cultures for bacteria and fungi were unsuccessful in the identification of a causative organism. Progressive enlargement of the lesion was noted despite intravitreal foscarnet, vancomycin, ceftazidime, and voriconazole. A pars plana vitrectomy and retinal and subretinal biopsy led to the identification of Nocardia veterana, a recently identified Nocardia species. A combination of linezolid, meropenem, azithromycin, ceftriaxone, and intravitreal amikacin resulted in eradication of the infection.

Conclusion

This is the first reported case of N. veterana endogenous endophthalmitis in an immunosuppressed patient. Pars plana vitrectomy with a subretinal biopsy was required to establish a diagnosis, as other testing including aqueous PCR and vitreous cultures were negative. The poor visual outcome in our patient highlights the importance of early consideration of Nocardia in the differential diagnosis of panuveitis with subretinal disease in the context of immunosuppression.

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.

First report of a brain abscess caused by Nocardia veterana

Among Nocardia species causing infections, Nocardia veterana is rarely isolated and is mostly described as causing pulmonary infections. This is the first presentation of a case of brain abscess attributable to an N. veterana infection in a patient with type 2 diabetes. Prolonged antibiotic therapy with trimethoprim-sulfamethoxazole led to successful clinical recovery.