Invasive Nocardia Infections across Distinct Geographic Regions, United States

Severe pneumonia caused by Nocardia otitidiscaviarum in a patient with bronchiectasis and IgA nephropathy: a case report

Background

Nocardia species are rare opportunistic pathogens in the clinic, with strong invasiveness and dissemination, that can cause serious pulmonary infection, especially in immunocompromised patients, chronic lung diseases and hormone use, and is easy to be missed and misdiagnosed, preventing patients from obtaining timely and effective treatment, resulting in a high mortality rate.

Case presentation

Here, we present a rare case of a patient with chronic bronchiectasis and IgA nephropathy who developed Nocardia otitidiscaviarum pneumonia shortly after hormone therapy. The patient presented with tongue and lip ulcers, chest distress, cough, expectoration, and fever as the initial symptoms, which were extremely similar to common bacterial pulmonary infections. The laboratory examination and pulmonary computer tomography results indicated pulmonary infection, but the blood and multiple sputum cultures failed to identify the pathogen. Empirical treatment with piperacillin/tazobactam sodium and ceftriaxone was ineffective, and the patient's condition worsened and progressed to respiratory failure. Subsequently, a bronchoscopy examination was performed, and the bronchoalveolar lavage fluid was collected for bacterial culture, which indicated Nocardia infection, however the treatment used of trimethoprim-sulfamethoxazole combined with imipenem was not effective. Finally, the patient was confirmed to have Nocardia otitidiscaviarum infection by mass spectrometry. According to the antibiotic sensitivity test and minimum inhibitory concentration (MIC) value results, Nocardia otitidiscaviarum was resistant to imipenem, so the treatment was changed to trimethoprim-sulfamethoxazole combined with linzolid. The patient's condition improved rapidly and he was discharged after his condition was stable.

Conclusion

This case reminded us that for patients with a history of chronic lung disease, when pulmonary infection occurs during hormone or immunosuppressive therapy for kidney disease, the possibility of Nocardia infection should be fully considered, and high-quality specimens should be collected as early as possible. Appropriate bacterial culture methods and efficient identification techniques should be adopted to promptly identify pathogens, and personalized treatment plans should be developed based on antibiotic sensitivity tests to save patients' lives.

Combination treatment with photodynamic therapy and antibiotic in refractory cutaneous nocardiosis: A case report

BACKGROUND

Effective management of cutaneous nocardiosis is hampered by the lack of defined treatment recommendations and frequently requires prolonged antibiotic therapy.

CASE PRESENTATION

This report describes a case of cutaneous nocardiosis who was effectively treated in a brief amount of time with three sessions of 5-aminolevulinic acid photodynamic therapy (ALA-PDT) in conjunction with antibiotics.

CONCLUSION

ALA-PDT combined with antibiotics may effectively treat refractory cutaneous nocardiosis.

The genus Nocardia as a source of new antimicrobials

The genus Nocardia comprises over 130 species of soil-dwelling actinomycetes, many of which are opportunistic pathogens. Beyond their pathogenicity, Nocardia exhibits significant biosynthetic potential, producing an array of diverse antimicrobial secondary metabolites. This review highlights notable examples of these compounds and explores modern approaches to unlocking their untapped biosynthetic potential. As a relatively underexplored genus, Nocardia represents a promising source for new antibiotics to combat the growing resistance crisis.

Multicenter systematic review of clinical characteristics, diagnostic optimization, and personalized treatment for brain Nocardia infections

This study provides a systematic review of 512 reported cases of Nocardia brain infections from 2000 to mid-2024. It focuses on analyzing clinical manifestations, radiological findings, bacterial identification methods, and antibiotic resistance patterns. Special attention is given to the differences in outcomes between immunocompromised and non-immunocompromised patients. We also explored personalized treatment approaches by analyzing outcome-related factors through correlation analysis and linear discriminant analysis. Imaging findings commonly showed brain abscesses, lesions, and mass effects, with a high prevalence of antibiotic resistance. Diagnostic methods using conventional microbiological cultures were less effective compared to advanced molecular diagnostics, which enhanced detection accuracy and reduced time to diagnosis. This review also identifies key factors influencing treatment outcomes, including the timely initiation of appropriate antibiotics, particularly the combination of sulfonamides and β-lactams, as well as the importance of surgical intervention. These findings underscore the necessity of improving diagnostic and therapeutic strategies to achieve early diagnosis and personalized treatment.

Brain abscess following solid organ transplantation: A 21-year retrospective study

BACKGROUND

Development of brain abscess following solid organ transplantation is associated with significant morbidity and mortality. We undertook a descriptive study to evaluate the etiology, clinical manifestations, diagnosis, management, and outcomes of brain abscess in solid organ transplant (SOT) recipients at three major transplant centers in the United States.

METHODS

This is a retrospective study of adults with brain abscess following SOT between January 2000 and June 2021 at Mayo Clinic sites in Arizona, Minnesota, and Florida.

RESULTS

A total of 39 patients were diagnosed with a brain abscess following SOT. The most common pathogens were Nocardia sp. (24 cases, 61.5% [Nocardia farcinica, 37.5%]), followed by fungi (12 cases, 30.7% [Aspergillus sp., 83.3%]). The majority were kidney transplant recipients (59%). Median time to brain abscess diagnosis was 1.3 years (range, 29 days-12 years) after SOT; 10 of 12 patients (83%) with fungal brain abscess were diagnosed within 1 year after SOT. Twelve patients underwent brain biopsy for diagnosis (25% Nocardia vs. 50% fungal), eight (20.5%) underwent surgical resection of the abscess, and 31 (79.5%) received antimicrobial therapy alone. Median time to brain abscess resolution was 166 days for Nocardia and 356 days for fungal pathogens. Eleven of 39 patients (28.2%) died as a result of their brain abscess, including four of 24 patients (16%) with Nocardia and six of 10 patients (60%) with Aspergillus brain abscess. All-cause mortality was 43.6%.

CONCLUSION

Brain abscess remains an uncommon infectious complication following SOT. Nocardia and fungi accounted for 92% of pathogens in our cohort. Fungal brain abscess portends a poor prognosis.

Breaking Through Resistance: Carbapenem-Resistant Nocardia?!-A Case Report

Nocardia is an emerging bacterial disease that often affects patients with compromised immune systems. As the number of patients undergoing solid organ transplants continues to rise, and as more cancer survivors are treated with long-term immune-modifying agents, corticosteroids, and immunosuppressive medications, organisms that typically pose no harm are becoming a public health concern. Carbapenems are usually a second-line therapy in the setting of Nocardia infections. We present the case of a patient who had an immunocompromised status and was diagnosed with Nocardia farcinica, which showed in vitro resistance to carbapenems. The symptoms were non-specific and had a common presentation with headache, fatigue, and a nonresponsive cough to usual cough drugs, although the infection was disseminated and had severe CNS and ocular involvement. The clinical course worsened when the carbapenem was withdrawn and markedly improved when it was re-administered, although the initial antibiogram showed resistance to carbapenems. Despite the observed in vitro resistance in the laboratory, the re-administration of carbapenems was beneficial, as both inflammatory markers and clinical status showed improvement. This was based on clinical judgment, which carefully evaluated the associated risks and benefits. Also, this raises the question of potential risks to develop real resistance to carbapenems of some Nocardia species, which could pose a significant challenge to healthcare. It could become a serious healthcare problem in the future and should prompt active environmental testing.

Pulmonary Nocardiosis in Renal Transplant Recipients From Pakistan: Risk Factors, Clinical Presentation, and Mortality

OBJECTIVES

Nocardia is an opportunistic infection among renal transplant recipients with an incidence of <1% but high mortality. Data from Pakistan are scarce. Our aim was to find the risk factors, clinical and radiographic findings, antimicrobial sensitivity, and outcomes of Nocardia infection among renal transplant recipients in Pakistan.

MATERIALS AND METHODS

All adult renal transplant recipients diagnosed with nocardiosis between 2013 and 2020 were included. The cases were matched 1:2 with controls based on sex, age (±1 year), and transplant date (±1 year). Risk factors, clinical features, antibiotic sensitivities and outcomes were analyzed.

RESULTS

A total of 48 patients developed nocardiosis. Around 25% of patients presented with disseminated disease. Median time from transplant to disease development was 2.68 years. High-dose methylprednisolone and presence of cytomegalovirus infection within 90 days of disease development were independent risk factors for Nocardia infection. The mortality rate was 20%. Central nervous system disease and cytomegalovirus infection within 90 days were significantly associated with mortality. The most susceptible drugs were co-trimoxazole and linezolid. Imipenem susceptibility was only 20%.

CONCLUSIONS

High-dose methylprednisolone and cytomegalovirus infection were independent risk factors for Nocardia infection. Central nervous system disease was associated with mortality. Nocardia species were highly resistant to ceftriaxone and imipenem in our patient population.

Nocardia brasiliensis Pyomyositis in an Immunocompetent Patient Following Gardening Activity

Nocardia pyomyositis in immunocompetent patients is a rare occurrence. The diagnosis may be missed or delayed with the risk of progressive infection and suboptimal or inappropriate treatment. We present the case of a 48-year-old immunocompetent firefighter diagnosed with pyomyositis caused by Nocardia brasiliensis acquired by direct skin inoculation from gardening activity. The patient developed a painful swelling on his right forearm that rapidly progressed proximally and deeper into the underlying muscle layer. Ultrasound imaging of his right forearm showed a 7-mm subcutaneous fluid collection with surrounding edema. Microbiologic analysis of the draining pus was confirmed to be N brasiliensis by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) Mass Spectrometry. After incision and drainage deep to the muscle layer to evacuate the abscess and a few ineffective antibiotic options, the patient was treated with intravenous ceftriaxone and oral linezolid for 6 weeks. He was then de-escalated to oral moxifloxacin for an additional 4 months to complete a total antibiotic treatment duration of 6 months. The wound healed satisfactorily and was completely closed by the fourth month of antibiotic therapy. Six months after discontinuation of antibiotics, the patient continued to do well with complete resolution of the infection. In this article, we discussed the risk factors for Nocardia in immunocompetent settings, the occupational risks for Nocardia in our index patient, and the challenges encountered with diagnosis and treatment. Nocardia should be included in the differential diagnosis of cutaneous infections, particularly if there is no improvement of "cellulitis" with traditional antimicrobial regimens and the infection extends into the deeper muscle tissues.