Pulmonary nocardiosis (PN) is an opportunistic infectious disease caused by Nocardia of the lungs, which lacks specificity in clinical symptoms and imaging, is rare in individuals with normal immune function, and is highly prone to clinical misdiagnosis and missed diagnosis.

A 55-year-old woman with normal immune function was admitted to the hospital due to a cough and expectoration for more than 20 days.

Chest computed tomography revealed a mass in the left hilum and obstructive atelectasis in the lingular segment of the left upper lobe. Initially suspected to be a malignant tumor, bronchoscopy with pathological examination suggested inflammation. Finally, metagenomic next-generation sequencing of pathological tissue confirmed PN.

After discharge, the patient regularly took trimethoprim-sulfamethoxazole for anti-infective treatment.

Regular follow-ups with the patient revealed that subsequent chest computed tomography scans showed a gradual reduction in the extent of the lesions, and the patient demonstrated a good clinical response and radiological improvement.

This case highlights the diagnostic complexity of PN. The radiological manifestations are diverse, commonly including pulmonary consolidation, nodules, and cavities, making it difficult to differentiate from other diseases. Clinicians need to be vigilant and find appropriate testing methods to improve the diagnostic rate of PN.

Infections caused by Nocardia species are relatively rare and primarily affect immunocompromised patients. There are few reported cases of Nocardia beijingensis causing empyema in patients with systemic lupus erythematosus (SLE). We present a case of a 49-year-old female patient with SLE on immunosuppressive therapy (corticosteroids and azathioprine), admitted with dyspnea and left-sided pleuritic chest pain. A diagnosis of large parapneumonic left pleural effusion was established based on blood tests, blind thoracentesis findings, and bronchoalveolar lavage results. The patient received empirical intravenous antibiotic therapy with imipenem/cilastatin and vancomycin without isolating the causative organism for 10 days. Three weeks postdischarge, the patient's left pleuritic chest pain worsened, prompting chest computed tomography that revealed multiple loculated pleural-abdominal wall fluid collections. Ultrasound-guided aspiration of these areas yielded pus cultured positive for N. beijingensis. The patient showed improvement following treatment with imipenem/cilastatin and trimethoprim/sulfamethoxazole. This case represents a rare manifestation of N. beijingensis causing pleural and abdominal wall empyema. Ultrasound-guided aspiration, targeting the loculated and encapsulated effusion, played a crucial role in confirming the diagnosis. Empirical treatment with imipenem/cilastatin combined with long-term oral trimethoprim/sulfamethoxazole was found to be effective.

Gender differences exist in the susceptibility, incidence, progression, and prognosis of bacterial infections in males and females, influenced by various factors including lifestyle and habits. Multiple reports have indicated that estrogen plays a crucial immunomodulatory role in many pathogenic microbial infections, highlighting a complex relationship between estrogen, its receptors, and bacterial infections. Estrogen and its receptors regulate host immune responses, affecting the host's ability to clear bacteria and thus influencing the likelihood and difficulty of infection eradication. Variations in estrogen levels may lead to differences in the occurrence and progression of bacterial infections, with estrogen playing varied roles in diseases caused by the same bacterial pathogens. The interaction between estrogen and bacterial infections represents a complex and crucial aspect of human physiology and clinical medicine. Understanding this interaction is essential for advancing infection prevention and treatment strategies. This article reviews the correlation and mechanisms between estrogen and bacterial infections, emphasizing the importance of further research in this field.

A 63-year-old man presented with right knee pain and swelling 16 months after undergoing right total knee arthroplasty. Inflammatory markers were elevated, and after 6 weeks of incubation, cultures grew Nocardia nova. Treatment included 2-stage exchange of the prosthetic joint, multiple wound debridements, and an extended course of antibiotics. A Staphylococcus epidermidis infection complicated treatment, but all infections were considered resolved 14 months after the initial joint infection diagnosis.

This report underscores the need to consider Nocardia nova as a cause of prosthetic joint infections and the potential for prolonged treatment.

Nocardia keratitis is a rare cause of microbial keratitis, primarily affecting patients in tropical and subtropical regions. Its diagnostic challenge arises from this keratitis uncommon presentation, which often mimics other infectious keratitis types, leading to delays in appropriate treatment. This case report aims to elucidate the complexities of diagnosing and managing Nocardia keratitis of a 41-year-old male who had a chronic, progressively worsening wreath-pattern corneal infiltrate and hypopyon following ocular trauma. Initial empirical treatments were ineffective. Diagnostic confirmation via corneal scraping culture enabled targeted antimicrobial therapy. Subconjunctival amikacin and topical tobramycin led to gradual improvement, though complications such as corneal scarring and neovascularization remained, indicating potential need for surgical intervention. This case emphasizes the importance of high clinical suspicion and precise laboratory diagnostics in managing rare cases of Nocardia keratitis. Establishing standardized treatment guidelines for rare ocular infections could improve clinical outcomes.

Nocardia species are aerobic, Gram-positive actinomycetes often causing opportunistic infections, particularly in immunocompromised hosts. Nocardia farcinica is notable for disseminated nocardiosis (DN), frequently involving the lungs and central nervous system (CNS). Cushing's syndrome (CS), characterized by hypercortisolemia, further predisposes patients to severe infections. We report a 73-year-old woman with ACTH-dependent CS due to a pituitary adenoma who developed DN with pleuropulmonary, CNS, and gluteal abscesses. Diagnosis was confirmed through cultures and MALDI-TOF MS, identifying N. farcinica. Resistance to standard antibiotics required a tailored regimen, including imipenem, amikacin, and moxifloxacin, alongside surgical management of abscesses and the adenoma. This case emphasizes the importance of rapid diagnostic methods and individualized therapies in managing DN with CS, a rare but severe combination. It highlights the need for vigilance in high-risk patients and contributes valuable insights for optimizing outcomes in such complex cases.

A 28-year-old male presented to an Australian hospital with sudden-onset headache and seizure following a kidney transplant for end-stage renal disease due to IgA nephropathy. Clinical approach to the cases and management of the diagnosed disease are discussed.

Linezolid is an oxazolidinone antibiotic that is mainly permitted to treat Gram-positive bacterial infections. Recent studies have shown that linezolid also has antibacterial effects on several other bacteria outside the package insert, including Mycobacterium tuberculosis, non-tuberculous mycobacteria (NTM), Nocardia, Corynebacterium, and anaerobes, etc. Interestingly, linezolid also has an in vitro inhibitory effect on fungi. This review focuses on the in vitro antibacterial activity of linezolid against microorganisms outside its antibacterial spectrum. We mainly listed the number of the tested strains, the minimum inhibitory concentration (MIC) range, MIC50, and MIC90 of linezolid against those pathogens outside the package insert. The results showed that among these tested pathogens, linezolid displayed strong inhibitory effects against M. tuberculosis, Nocardia, and Corynebacterium, with an MIC range of ≤2 μg/mL. As for NTM, linezolid exhibited moderate to potent inhibitory effects against the strains of different species with an MIC range of 0.06-128 μg/mL. Moreover, linezolid was reported to have a species-dependent inhibitory effect on anaerobes at a concentration range of 0.003-16 μg/mL. Furthermore, linezolid could enhance azoles and amphotericin B's antifungal activity on Candida synergistically. It is hoped that this analysis can provide data for expanding the application of linezolid, make the off-label drug use have more compelling evidence, and provide clues for the development of new drugs.

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.

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.

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.

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.

Drug susceptibility testing (DST) for Nocardia spp. is essential to initiate effective antibiotic therapy. Currently, the only recommended technique is the determination of minimum inhibitory concentrations (MICs) by microdilution. This method can be tedious to perform, despite the availability of ready-to-use plates. Herein, the aim was to determine the critical inhibition diameters specific to Nocardia spp.

MICs of 134 Nocardia isolates were determined by microdilution. Interpretative categories (Susceptible/Intermediate/Resistant) were determined using Clinical and Laboratory Standards Institute breakpoints. In parallel, disk diffusion DST was performed. Receiver-operating-characteristic (ROC) curves were constructed to determine the inhibition diameter value that best discriminated between susceptible and non-susceptible strains (intermediate/resistant). The category agreement (CA), the rate of major (maj) and very major (vmj) discrepancies between microdilution and disk diffusion method was calculated.

For tobramycin, the critical diameter of 19 mm (diameter ≤ 19 mm = resistant strain; diameter > 19 mm = susceptible strain) provided a CA of 98.5%, 0.0% vmj, and 2.9% maj discrepancies, reaching strictly the acceptable performance criteria defined by the U.S. Food and Drug Administration (FDA). For amikacin, the critical diameter of 25 mm (diameter ≤ 25 mm = resistant strain; diameter > 25 mm = susceptible strain) provided a CA of 98.5%, 0.0% vmj, and 1.5% maj discrepancies. For imipenem, excluding N. farcinica and N. cyriacigeorgica, the critical diameter of 29 mm (diameter ≤ 29 mm = resistant strain; diameter > 29 mm = susceptible strain), provided a CA of 98.6%, 0.0% vmj, and 0.0% maj discrepancies. Despite an estimated vmj rate 0.0%, the 95%-confident-interval exceeded the FDA criteria due to an insufficient number of amikacin/imipenem-resistant strains. For other tested antibiotics (ciprofloxacin, moxifloxacin, amoxicillin-clavulanate, ceftriaxone, cotrimoxazole, linezolid), the FDA criteria were not reached.

Although the FDA criteria were mostly unmet, disk diffusion DST was suitable to accurately categorize Nocardia isolates into interpretative categories for the aminoglycosides and imipenem only, excluding species N. farcinica and N. cyriacigeorgica.

Nocardia is a conditionally pathogenic bacterium found in the natural environment and is an aerobic bacterium, which causes severe pneumonia relatively rarely. The diagnosis of primary Nocardia infection is always made late due to the nonspecific clinical presentation of patients with Nocardia infection and the time required for Nocardia culture. Due to its rarity and nonspecific clinical presentation, patient survival is often compromised due to misdiagnosis.

A 53-year-old woman with autoimmune cirrhosis was treated with glucocorticoids. Three and a half months later the patient developed fever, nausea, cough and sputum, treated with empirical antibiotics, and the patient occurred type I respiratory failure.

Nocardia was identified by sputum culture micromorphology and Meriere matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF).

The patient was treated with trimethoprim-sulfamethoxazole (TMZ), and the patient's oxygen saturation recovered significantly.

The patient's overall recovery was slow due to decreased albumin (ALB) and increased procalcitonin (PCT) caused by the patient's cirrhosis. Due to economic reasons, the family gave up, asked to be discharged.

In our report, patients with underlying disease are immunocompromised and at increased risk of infection with conditionally pathogenic bacteria. Nocardia has no specific presentation and is often overlooked clinically. Treatment of these patients should not be limited to common bacteria or viruses, but should consider rare opportunistic pathogens, and we need to be vigilant for Nocardia infections and timely use of sulfonamide antibiotics to reduce mortality.

Nocardiosis in patients after allogeneic hematopoietic stem cell transplantation (HSCT) is rare, but is associated with a significant mortality risk. Although trimethoprim-sulfamethoxazole (TMP/SMX) remains the cornerstone of nocardiosis treatment, optimal alternative therapies for patients intolerant to TMP/SMX are not well-established. Herein, we report a case of disseminated nocardiosis with bacteremia and multiple lesions in the lungs and brain caused by Nocardia farcinica, in a 60-year-old man who had previously undergone allogeneic HSCT and was receiving immunosuppressants for severe chronic graft-versus-host disease. The patient received atovaquone for the prophylaxis of Pneumocystis pneumonia because of a previous serious allergic reaction to TMP/SMX. The patient was initially treated with imipenem/cilastatin and amikacin, which were later switched to ceftriaxone and amikacin based on the results of antimicrobial susceptibility testing. After switching to oral levofloxacin and a standard dose of minocycline, the patient experienced a single recurrence of brain abscesses. However, after switching to oral moxifloxacin and high-dose minocycline, the patient did not experience any relapses during the subsequent two years and seven months of treatment. In treating nocardiosis with brain abscesses, it is crucial to select oral antibiotics based on the antimicrobial susceptibility test results and pharmacokinetics, especially when TMP/SMX is contraindicated. A combination of oral moxifloxacin and high-dose minocycline could be a promising alternative therapy.

The prolonged treatment recommended for nocardiosis does not rely on strong evidence. Consequently, some clinicians opt shorter therapy in certain circumstances. We assessed the effectiveness of shorter therapy.

A multi-center retrospective cohort study comprising individuals diagnosed with nocardiosis between 2007 and 2022. We classified all patients who survived 90 days into three groups according to treatment duration: short (≤ 90 days), intermediate (91-180 days), and prolonged (> 180 days). We compared baseline characteristics (comorbidities, immune status) and nocardiosis manifestations across the unadjusted treatment groups, one-year all-cause mortality, disease relapse, and antibiotic-related adverse events to identify patients who may safely receive the short course.

We detected 176 patients with nocardiosis, their median age was 65 years; 74 (42%) were women. Forty-three (24%) patients died within 90 days. Of the remaining 133, 37 (28%) patients received short therapy, 40 (30%) intermediate, and 56 (42%) prolonged treatment duration. Longer courses were more likely to be administered to patients with immunosuppression, disseminated nocardiosis, and N. farcinica infection. Within a year, 20 (15%) individuals died and 2 (2%) relapsed. Treatment duration was not associated with either mortality (p = 0.945) or relapse (p = 0.509). Nocardiosis was the cause of death in only one patient, receiving a prolonged course. Of 73 patients with solitary pulmonary nocardiosis, 20 (27%) received short duration. None relapsed and 2 (10%) died, both immunocompromised. The rate of AE was similar across the groups.

With clinically guided case-by-case patient selection nocardiosis can be safely treated for durations significantly shorter than traditionally recommended.

Brain abscesses (BA) are focal parenchymal infections that remain life-threatening conditions. Polymicrobial BAs (PBAs) are complex coinfections of bacteria or bacterial and nonbacterial pathogens such as fungi or parasites, with diagnostic and therapeutic challenges. In this article, we comprehensively review the prevalence, pathogenesis, clinical manifestations, and microbiological, histopathological, and radiological features of PBAs, as well as treatment and prognosis. While PBAs and monomicrobial BAs have some similarities such as nonspecific clinical presentations, PBAs are more complex in their pathogenesis, pathological, and imaging presentations. The diagnostic challenges of PBAs include nonspecific imaging features at early stages and difficulties in identification of some pathogens by routine techniques without the use of molecular analysis. Imaging of late-stage PBAs demonstrates increased heterogeneity within lesions, which corresponds to variable histopathological features depending on the dominant pathogen-induced changes in different areas. This heterogeneity is particularly marked in cases of coinfections with nonbacterial pathogens such as Toxoplasma gondii. Therapeutic challenges in the management of PBAs include initial medical therapy for possibly underrecognized coinfections prior to identification of multiple pathogens and subsequent broad-spectrum antimicrobial therapy to eradicate identified pathogens. PBAs deserve more awareness to facilitate prompt and appropriate treatment.

In this article we report a case of disseminated nocardiosis caused by Nocardia otitidiscaviarum in an immunocompetent patient with chronic obstructive pulmonary disease (COPD) who complained of a cough, followed by skin and intracranial lesions. On metagenomic next-generation sequencing (mNGS) technology of respiratory samples (bronchoalveolar lavage fluid, BALF) Nocardia otitidiscaviarum was identified. The patient was treated with therapy combined with a low dose of TMP-SMX and imipenem cilastatin sodium and had a favorable outcome. The timely diagnosis of Nocardia with the help of mNGS technology and early rational treatment of TMP-SMX can help improve the prognosis.

Nocardiosis is an uncommon infectious disease that bears certain similarities to tuberculosis, with a continuous increase in its incidence and a poor prognosis. In traditional Chinese medicine, the leaves of Cajanus cajan (L.) Millsp. are employed to treat wounds, malaria, coughs, and abdominal pain.

In this study, we investigated the effects and mechanisms of longistylin A (LGA), a natural stilbene isolated from C. cajan, as a potential antibiotic against nocardiosis.

LGA was isolated from the leaves of C. cajan and assessed using a minimum bactericidal concentration (MBC) determination against Nocardia seriolae. Multi-omics analysis encompassing genes, proteins, and metabolites was conducted to investigate the impact of LGA treatment on N. seriolae. Additionally, quantitative analysis of 40 cytokinins in N. seriolae mycelium was performed to assess the specific effects of LGA treatment on cytokinin levels. Cryo-scanning electron microscopy was utilized to examine morphological changes induced by LGA treatment, particularly in the presence of exogenous trans-zeatin-O-glucoside (tZOG). The therapeutic effect of LGA was investigated by feeding N. seriolae-infected largemouth bass.

LGA exhibited significant efficacy against N. seriolae, with MBC value of 2.56 μg/mL. Multi-omics analysis revealed that LGA disrupted glycerophospholipid metabolism and hormone biosynthesis by notably reducing the expression of glycerol-3-phosphate dehydrogenase and calmodulin-like protein. Treatment with LGA markedly disrupted 12 distinct cytokinins in N. seriolae mycelium. Additionally, the addition of exogenous tZOG counteracted the inhibitory effects of LGA on filamentous growth, resulting in mycelial elongation and branching. Furthermore, LGA treatment improved the survival rate of largemouth bass infected with N. seriolae.

We found for the first time that LGA from C. cajan exhibited significant efficacy against N. seriolae by interfering with glycerophospholipid metabolism and cytokinin biosynthesis.

Nocardia spp. is an opportunistic pathogen capable of causing localized and disseminated infections in immunocompromised hosts. It is critical for serious infections to have an early and accurate identification of this pathogen in order to enable timely and focused combination antimicrobial treatment.

We describe the case of an 87-year-old patient previously treated for myasthenia gravis with corticosteroids and azathioprine. Patient was admitted at the emergency department with clinical signs of sepsis with cellulitis of right hand associated with injury acquired after gardening and trimming roses and did not respond to empirical antimicrobial treatment. Computerized tomography revealed pulmonary infiltrates with inflammatory etiology. Nocardia cyriacigeorgica was cultivated from blood culture, skin swab, abscess aspirate, and endotracheal aspirate and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), 16S rRNA sequencing, and whole genome sequencing (WGS). Susceptibility testing was performed with E-test (bioMerieux, Marcy-l'Étoile, France), and corresponding resistance genes were detected by WGS. Resistance to amoxicillin-clavulanate, azithromycin, ciprofloxacin, and vancomycin was detected by both methods. Despite all interventions and the patient receiving antimicrobial treatment including imipenem-cilastatin, amikacin, and trimethoprim-sulfamethoxazole, the course and outcome of infection were unfavorable.

We would like to emphasize the need to consider the possibility of disseminated Nocardia infection in immunocompromised patients, especially in patients receiving long-term corticosteroid treatment with skin infections and/or cavitary lung lesions, especially if these do not improve with standard antimicrobial treatment. Precise species identity provides a critical guide for physicians in the choice of targeted treatment. Thanks to MALDI-TOF MS, Nocardia spp. identification is now available in routine lab work. WGS is still inevitable for the identification of uncommon and novel species due to the high sequence similarities between closely related species and the genetic diversity of that genus.

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.

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.

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%.

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.

We present a rare case of an immunocompetent 49-year-old male agriculturalist from India diagnosed with Nocardia otitidiscaviarum pneumonia. Nocardia species are ubiquitous gram-positive, partially acid-fast bacilli that predominantly infect immunocompromised individuals. Only 0.3% to 2.9% of all nocardiosis cases are attributed to N. otitidiscaviarum. The patient presented with a 25-day history of wet cough and high-grade fever, with bilateral bronchial breath sounds on chest auscultation and findings consistent with pneumonia on chest X-ray. During hospitalization, multiple treatment revisions were made. On admission, empiric antibiotic therapy against community-acquired pneumonia was initiated. Later, GeneXpert sputum testing for Mycobacterium tuberculosis complex (MTBC) was positive for MTBC DNA. Suspected tuberculosis with a secondary infection prompted a treatment switch to antitubercular therapy (ATT) along with meropenem. Despite changes to treatment, the patient continued to deteriorate with no signs of clinical improvement. ATT with meropenem was discontinued when a repeat GeneXpert for MTBC was negative, ruling out tuberculosis. Slow-growing bronchial wash culture identified the rare pathogen N. otitidiscaviarum, prompting an urgent referral to a specialized Infectious Diseases team. Treatment was then tailored according to antibiotic resistance-sensitivity testing. Targeted multidrug antibiotic therapy with trimethoprim-sulfamethoxazole and amikacin against N. otitidiscaviarum facilitated gradual clinical improvement. This case underscores the importance of considering uncommon pathogens in differential diagnosis and highlights the critical role of microbiological diagnostics in guiding effective treatment. Drug resistance and changing bacterial pathogenicity trends must not be overlooked. The round-about antibiotic treatment changes in this case point to the necessity for faster diagnostic methods in identifying Nocardia species. Further research into rapid diagnostic methods and up-to-date treatment guidelines are warranted to optimize outcomes in nocardiosis management.

Suppurative thyroiditis is a rare entity with a low incidence in thyroid diseases, manifesting with pain, fever, dysphagia, and dysphonia. Its infrequency is explained by the thyroid gland's resistance to infections due to its encapsulated position, high blood flow, bactericidal action of iodine, and extensive lymphatic network. We present the first report in the literature of a 72-year-old woman with a history of inflammatory myopathy and immunosuppression diagnosed with suppurative thyroiditis co-infected with Nocardia spp. and Mycobacterium tuberculosis. This entity requires a high clinical suspicion, and fine-needle aspiration biopsy (FNAB) is preferred as the diagnostic method for microbiological sampling. Although rare, it carries high morbidity and mortality if not suspected in time.

Nocardia species can affect both immunocompetent and immunocompromised people.

This retrospective study, from 2009 to 2022, aims to compare the survival analyses of pulmonary nocardiosis in AIDS and non-AIDS patients in northeastern Thailand.

A total of 215 culture-confirmed cases of pulmonary nocardiosis: 97 with AIDS and 118 without AIDS. The median CD4 count of AIDS patients was 11 cells/µL (range: 1-198), and 33% had concurrent opportunistic infections. 63.6% of 118 non-AIDS patients received immunosuppressive medications, 28.8% had comorbidities, and 7.6% had no coexisting conditions. Disseminated nocardiosis and pleural effusion were more prevalent among AIDS patients, whereas non-AIDS patients revealed more shock and respiratory failure. One hundred-fifty patients underwent brain imaging; 15 (10%) had brain abscesses. Patients with pulmonary nocardiosis have overall 30-day and 1-year mortality rates of 38.5% (95% CI: 32.3%, 45.4%) and 52.1% (95% CI: 45.6%, 58.9%), respectively. The Cox survival analysis showed that AIDS patients with disseminated nocardiosis had a 7.93-fold (95% CI: 2.61-24.02, p < 0.001) increased risk of death within 30 days compared to non-AIDS patients when considering variables such as age, Charlson comorbidity index, concurrent opportunistic infections, duration of illness, shock, respiratory failure, multi-lobar pneumonia, lung abscesses, and combination antibiotic therapy. While AIDS and pulmonary nocardiosis had a tendency to die within 30 days (2.09 (95% CI, 0.74-5.87, p = 0.162)).

AIDS with pulmonary nocardiosis, particularly disseminated disease, is a serious opportunistic infection. Early diagnosis and empiric treatment with a multidrug regimen may be the most appropriate approach in a resource-limited setting.

Nocardia is an ubiquitous soil organism. As an opportunistic pathogen, inhalation and skin inoculation are the most common routes of infection. Lungs and skin are the most frequent sites of nocardiosis. Testis is a highly unusual location for nocardiosis.

We report the case of an immunocompromised 75-year-old-man admitted for fever of unknown origin. He presented with skin lesions after gardening and was first suspected of Mediterranean spotted fever, but he did not respond to doxycycline. Then, physical examination revealed new left scrotal swelling that was compatible with a diagnosis of epididymo-orchitis. The patient's condition did not improve despite empirical antibiotic treatment with the onset of necrotic scrotal abscesses requiring surgery. Nocardia brasiliensis yielded from the removed testis culture. High-dose trimethoprim-sulfamethoxazole and ceftriaxone were started. Multiple micro-abscesses were found in the brain and spinal cord on imaging studies. After 6 weeks of dual antibiotic therapy for disseminated nocardiosis, slight regression of the brain abscesses was observed. The patient was discharged after a 6-month course of antibiotics and remained relapse-free at that time of writing these lines. Trimethoprim-sulfamethoxazole alone is meant to be pursued for 6 months thereafter. We undertook a literature review on previously reported cases of genitourinary and urological nocardiosis; to date, only 36 cases have been published with predominately involvement of kidney, prostate and testis.

To the best of our knowledge, this is the first case of Nocardia brasiliensis simultaneously infecting skin, testis, brain and spinal cord in an immunocompromised patient. Knowledge on uncommon forms of nocardiosis remains scarce. This case report highlights the difficulty of diagnosing atypical nocardiosis and the importance of prompt bacteriological sampling in case of empirical antibiotics failure.

Nocardiosis is an infectious disease caused by Nocardia spp., mainly affecting immunocompromised hosts. Nocardia infection is not common; especially Nocardia wallacei infection is even rarer. The patient, female, 61 years old, farmer, has been working in the field for a long time and has normal immune function. Her main clinical manifestation was persistent back pain. Chest-enhanced computed tomography showed pulmonary inflammation. Rare pathogen Nocardia wallacei was detected in alveolar lavage fluid using matrix-assisted laser destructive ionization time-of-flight mass spectrometry. She received treatment with linezolid and was discharged after her condition improved.

We introduce the case of a male patient in his 60s who was admitted to our emergency department with a persisting sore throat for the last 3 weeks and dysphagia. Fibre-endoscopic evaluation revealed an asymmetry at the base of the tongue. In combination with elevated white cell count and C reactive protein, a computerized tomography showed a superinfected thyroglossal duct cyst. Intravenous antibiotics were initiated, and the patient was taken to the operating room for cervicotomy. The microbiological swab taken intraoperatively detected Nocardia paucivorans Additional imaging revealed disseminated nocardiosis with cerebral and pulmonary manifestations.The patient was treated with oral trimethoprim/sulfamethoxazole and, over time, showed complete remission of central nervous system lesions and improvement of pulmonary involvement. Following this, the treatment was stopped 8 months after the initial diagnosis. In this report, we discuss treatment standards and outcomes of nocardiosis based on our management strategies of our patient.

In China, due to the large population, infections caused by Nocardia may not be as rare. Unfortunately, there is still inadequate knowledge of the clinical impact caused by Nocardia. This study aimed to compare the clinical characteristics and treatment of localized and disseminated nocardiosis.

The clinical and microbiological data of patients diagnosed with nocardiosis in a tertiary hospital in Beijing from July 2011 to July 2021 were collected and retrospectively analyzed.

Among the 54 nocardiosis cases, 34 cases were in the localized infection group, while 20 cases in the disseminated infection group. The proportion of patients with chronic structural lung disease was higher in the localized group (P=0.010). In contrast, patients with disseminated infections were more prone to receive long-term glucocorticoids and/or immunosuppressants (P=0.027). Pulmonary nodules were prominent features of imaging changes in patients with disseminated infections (P=0.027) whereas bronchial dilatation was more common in patients with localized infections (P=0.025). In addition, the disseminated group had longer average hospitalization days relative to the localized group (P=0.016), but there was no significant difference in mortality between them (P=0.942).

There were differences in the clinical profiles between patients with localized and disseminated nocardiosis in terms of clinical presentation, infection site, radiological features, treatment, and prognosis. These findings may provide references for the management and treatment of patients with nocardiosis.

Nocardia disease is an opportunistic infection, the occurrence is rare and mostly occurs in patients with immune deficiency. Even if the patient is immunocompetent, it can still be life-threatening. This case report describes a previously healthy 78-year-old male farmer with lung lesions discovered on a computerized tomography scan. Combined with the patient's history of fever and the results of elevated laboratory markers associated with inflammation, the patient was diagnosed with a lung infection. After escalating empirical broad-spectrum antibiotics, antiviral and antifungal therapy, the patient continued to deteriorate to septic shock. In the meanwhile, the patient's sputum was cultured repeatedly, and no obvious positive pathogenic bacteria were found. Considering the patient was elderly and that these lesions were solid with burr signs, as well as the progression after antimicrobial therapy cancer was considered in the differential diagnosis. Artificial intelligence (YITU, Hangzhou Yitu Medical Technology Limited Company) was also applied, and it also calculated that these lesions were cancerous. The patient received a puncture biopsy of the largest lung lesion. During the puncture pus was withdrawn from largest lung lesion. Culture and metagenome next-generation sequencing (mNGS) detection performed on pus indicated Nocardia otitidiscaviarum. The test report of the mNGS is also attached with a susceptibility report of commonly used clinical antibiotics to this Nocardia spp. Using this result, the patient's disease was quickly controlled after selecting the targeted drug compound sulfamethoxazole and intravenous meropenem for treatment. In view of the high misdiagnosis rate and poor sensitivity of culture for Nocardia spp., this case emphasized mNGS playing a key role in the diagnosis and selection of effective antibiotics for the treatment of Nocardia spp. lung infections.

Nocardiosis is primarily an opportunistic infection affecting immunocompromised individuals, with a predilection for the lungs, brain, or skin in those with compromised immune function. Granulomatous hepatitis caused by Nocardia is a rare clinical manifestation. This study aims to provide a systematic overview of the clinical features of Nocardiosis caused by Nocardia farcinica, enhancing our understanding of this disease.

We report a case of a 75-year-old male with no underlying diseases presenting with a history of "recurrent fever for more than 4 months", along with fatigue, poor appetite, and pleural and abdominal effusion. Despite treatment at multiple hospitals, the patient showed little improvement. Chest CT revealed chronic inflammation, small nodules, bilateral pleural effusion, and pleural thickening. Abdominal CT indicated multiple low-density lesions in the liver, multiple small calcifications, and abdominal effusion.

Liver biopsy suggested inflammatory changes, with focal granuloma formation. Metagenomic next-generation sequencing (mNGS) of liver tissue indicated Nocardia farcinica, leading to the final diagnosis of disseminated Nocardia farcinica granulomatous hepatitis.

Nocardia infection is a rare disease primarily observed in immunocompromised patients but can also occur in those with normal immune function. The clinical and radiological features lack specificity; however, the utilization of mNGS technology enables rapid identification of the pathogenic microorganism. Nocardia farcinica is generally susceptible to sulfonamide drugs and amikacin, offering viable treatment options.

Nocardia farcinica is one of the most common Nocardia species causing human infections. It is an opportunistic pathogen that often infects people with compromised immune systems. It could invade human body through respiratory tract or skin wounds, cause local infection, and affect other organs via hematogenous dissemination. However, N. farcinica-caused bacteremia is uncommon. In this study, we report a case of bacteremia caused by N. farcinica in China.

An 80-year-old woman was admitted to Peking Union Medical College Hospital with recurrent fever, right abdominal pain for one and a half month, and right adrenal gland occupation. N. farcinica was identified as the causative pathogen using blood culture and plasma metagenomics next-generation sequencing (mNGS). The clinical considerations included bacteremia and adrenal gland abscess caused by Nocardia infection. As the patient was allergic to sulfanilamide, imipenem/cilastatin and linezolid were empirically administered. Unfortunately, the patient eventually died less than a month after the initiation of anti-infection treatment.

N. farcinica bacteremia is rare and its clinical manifestations are not specific. Its diagnosis depends on etiological examination, which can be confirmed using techniques such as Sanger sequencing and mNGS. In this report, we have reviewed cases of Nocardia bloodstream infection reported in the past decade, hoping to improve clinicians' understanding of Nocardia bloodstream infection and help in its early diagnosis and timely treatment.

Nocardia is a ubiquitous saprophyte capable of causing human disease. Disease is primarily respiratory or cutaneous, usually acquired via inhalation or inoculation. Under the influence of environmental and host factors, Nocardia incidence and species distribution demonstrate geographical variation.

To examine for differences in Nocardia incidence within Western Australia (WA) and analyse species distribution in the context of prior published studies. To analyse antibiogram data from a nationwide passive antimicrobial resistance surveillance program.

Retrospective extraction of laboratory data for Western Australian Nocardia isolates over a 21-year period. Analysis of Nocardia antimicrobial susceptibility testing data submitted to the Australian Passive Antimicrobial Resistance Surveillance (APAS) program between 2005 and 2022.

Nine hundred sixty WA isolates were identified, giving an annual incidence of 3.03 per 100 000 population with apparent latitudinal variation. The four most common species identified within WA and amongst APAS isolates were N. nova, N. cyriacigeorgica, N. brasiliensis and N. farcinica. APAS data demonstrated that all species exhibited high rates of susceptibility to linezolid (100%) and trimethoprim-sulfamethoxazole (98%). Amikacin (>90% susceptibility for all species except N. transvalensis) was the next most active parenteral agent, superior to both carbapenems and third-generation cephalosporins. Susceptibility to oral antimicrobials (other than linezolid) demonstrated significant interspecies variation.

We demonstrate geographical variation in the distribution of Nocardia incidence. Four species predominate in the Australian setting, and nationwide data confirm a high in vitro susceptibility to trimethoprim-sulphamethoxazole and linezolid, justifying their ongoing role as part of first-line empiric therapy.

The aim of this study was to investigate the clinical features of Nocardia infections, antibiotic resistance profile, choice of antibiotics and treatment outcome, among others. In addition, the study compared the clinical and microbiological characteristics of nocardiosis in bronchiectasis patients and non-bronchiectasis patients.

Detailed clinical data were collected from the medical records of 71 non-duplicate nocardiosis patients from 2017 to 2023 at a tertiary hospital in Zhengzhou, China. Nocardia isolates were identified to the species level using MALDI-TOF MS and 16S rRNA PCR sequencing. Clinical data were collected from medical records, and drug susceptibility was determined using the broth microdilution method.

Of the 71 cases of nocardiosis, 70 (98.6%) were diagnosed as pulmonary infections with common underlying diseases including bronchiectasis, tuberculosis, diabetes mellitus and chronic obstructive pulmonary disease (COPD). Thirteen different strains were found in 71 isolates, the most common of which were N. farcinica (26.8%) and N. cyriacigeorgica (18.3%). All Nocardia strains were 100% susceptible to both TMP-SMX and linezolid, and different Nocardia species showed different patterns of drug susceptibility in vitro. Pulmonary nocardiosis is prone to comorbidities such as bronchiectasis, diabetes mellitus, COPD, etc., and Nocardia is also frequently accompanied by co-infection of the body with pathogens such as Mycobacterium and Aspergillus spp. Sixty-one patients underwent a detailed treatment regimen, of whom 32 (52.5%) received single or multi-drug therapy based on TMP-SMX. Bronchiectasis was associated with a higher frequency of Nocardia infections, and there were significant differences between the bronchiectasis and non-bronchiectasis groups in terms of age distribution, clinical characteristics, identification of Nocardia species, and antibiotic susceptibility (P < 0.05).

Our study contributes to the understanding of the species diversity of Nocardia isolates in Henan, China, and the clinical characteristics of patients with pulmonary nocardiosis infections. Clinical and microbiologic differences between patients with and without bronchiectasis. These findings will contribute to the early diagnosis and treatment of patients.

The purpose of the present study was to evaluate the in vitro activity of tedizolid against several clinically significant species of Nocardia by comparing with that of linezolid. A total of 286 isolates of Nocardia species, including 236 clinical isolates recovered from patients in Japan and 50 strains (43 species) purchased from NITE Biological Resource Center, were studied. Antimicrobial susceptibility testing was performed using the broth microdilution method. For the 286 Nocardia isolates, the minimal inhibitory concentration (MIC)50 and MIC90 values of tedizolid were 0.25 and 0.5 μg/ml, and those of linezolid were 2 and 2 μg/ml, respectively. The distribution of the linezolid/tedizolid ratios (MICs of linezolid/MICs of tedizolid) showed that tedizolid had four- to eight-fold higher activity than linezolid in 96.1% (275/286) of Nocardia isolates. Both the tedizolid and linezolid MIC90 values for Nocardia brasiliensis were two-fold higher than those for the other Nocardia species. Both tedizolid and linezolid had low MIC values, 0.25-1 μg/ml and 0.5-4 μg/ml, respectively, even against nine isolates (five species) that were resistant to trimethoprim/sulfamethoxazole. One Nocardia sputorum isolate showed reduced susceptibility to tedizolid (4 μg/ml). Bioinformatics analysis suggests different resistance mechanisms than the oxazolidinone resistance seen in enterococci and staphylococci.

The authors have no conflicts of interest.

Human brucellosis is an infectious disease caused by Brucella and is often misdiagnosed for atypical manifestations including fever of unknown origin, headache, weakness, among else. Nocardiosis is a zoonotic disease caused by the genus Nocardia, which usually spreads through the respiratory tract, skin, and digestive tract. Limited research has documented cases of co-infection involving both Brucella and Nocardia pathogens in patients. A 55-year-old male was admitted to our hospital with intermittent high-grade fever. Following sputum and blood cultures, as well as other laboratory examinations, the patient was diagnosed with concurrent brucellosis and nocardiosis. According to recommendations of previous studies and reports, the patient was successively treated with levofloxacin, doxycycline, piperacillin sodium and sulbactam sodium, trimethoprim-sulfamethoxazole, rifampicin, and tigecycline, after which the patient recovered and was discharged. Brucella and Nocardia are both opportunistic pathogens and simultaneous infection of Brucella and Nocardia is relatively rare. If patients continue to experience persistent fever despite receiving empirical antibiotic therapy, it becomes necessary to conduct examinations to identify potential atypical pathogens, including Brucella and Nocardia. Sputum staining, sputum culture, and blood culture are critical auxiliary examinations during clinical practice. The treatment plan should be selected based on guidelines and the individual patient's condition. Regular reevaluation should be conducted, and antimicrobial agents should be adjusted accordingly.

Nocardiosis is a rare opportunistic infection that is classically observed in immunocompromised patients but can also affect immunocompetent individuals. It tends to involve the lung, central nervous system, and skin and is often misdiagnosed.

Nocardia species, which are ubiquitous in the environment, form lesions primarily in immunocompromised patients via oral or cutaneous infection. Some of these Nocardia species, such as N. farcinica, also infect the central nervous system via hematogenous dissemination, which rarely results in brain abscesses. Notably, N. farcinica is resistant to numerous antimicrobial drugs used in empirical therapy, necessitating the intervention of an infectious disease specialist. To date, no case of antimicrobial stewardship teams (ASTs) playing a central role in community hospitals without an infectious disease specialist has been reported. Here, we describe a case of N. farcinica-associated brain abscess in a small-to-medium-sized hospital with no infectious disease department or specialist, in which the AST assisted in the identification of the causative organism and in selecting appropriate therapeutic agents, ultimately leading to a cure. The patient was an 88-year-old man with a high fever. He had been taking prednisolone (10-15 mg/day) for approximately 1 year for pemphigoid. Considering the possibility of fever owing to bacteremia of cutaneous origin, ampicillin/sulbactam antimicrobial therapy at 6 g/day was initiated. A subsequent close examination led to the diagnosis of a brain abscess. Emergency abscess drainage was performed by a neurosurgeon, and postoperative antimicrobial combination therapy comprising ceftriaxone (4 g/day), vancomycin (2 g/day), and metronidazole (1,500 mg/day) was commenced. The AST suspected Nocardia infection earlier, but further testing was difficult to perform at this facility. Therefore, by requesting assistance from Nagoya University Hospital, we performed early bacterial identification by mass spectrometry and appropriate antimicrobial susceptibility testing by a custom panel on day 11. The patient was non-responsive to all the previously used antibiotics at the time of admission. On day 13 after admission, the patient was successfully treated with trimethoprim-sulfamethoxazole (TMP-SMX) and imipenem/cilastatin sodium, and the patient was cured. The AST can be as effective as an infectious disease specialist when a strong working relationship is established between the team and clinicians. Further, the activities of the AST can improve patient survival via active medical support in collaboration with attending physicians.

Whether trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis prevents nocardiosis in solid organ transplant (SOT) recipients is controversial.

To assess the effect of TMP-SMX in the prevention of nocardiosis after SOT, its dose-response relationship, its effect on preventing disseminated nocardiosis, and the risk of TMP-SMX resistance in case of breakthrough infection.

A systematic review and individual patient data meta-analysis.

MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, Web of Science Core Collection, and Scopus up to 19 September 2023.

(a) Risk of nocardiosis between SOT recipients with and without TMP-SMX prophylaxis, or (b) sufficient details to determine the rate of TMP-SMX resistance in breakthrough nocardiosis.

SOT recipients.

TMP-SMX prophylaxis versus no prophylaxis.

Risk Of Bias In Non-randomized Studies-of Exposure (ROBINS-E) for comparative studies; dedicated tool for non-comparative studies.

For our primary outcome (i.e. to determine the effect of TMP-SMX on the risk of nocardiosis), a one-step mixed-effects regression model was used to estimate the association between the outcome and the exposure. Univariate and multivariable unconditional regression models were used to adjust for the potential confounding effects. Certainty of evidence was assessed using Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

Individual data from three case-control studies were obtained (260 SOT recipients with nocardiosis and 519 uninfected controls). TMP-SMX prophylaxis was independently associated with a significantly decreased risk of nocardiosis (adjusted OR = 0.3, 95% CI 0.18-0.52, moderate certainty of evidence). Variables independently associated with an increased risk of nocardiosis were older age, current use of corticosteroids, high calcineurin inhibitor concentration, recent acute rejection, lower lymphocyte count, and heart transplant. Breakthrough infections (66/260, 25%) were generally susceptible to TMP-SMX (pooled proportion 98%, 95% CI 92-100).

In SOT recipients, TMP-SMX prophylaxis likely reduces the risk of nocardiosis. Resistance appears uncommon in case of breakthrough infection.

Nocardiosis manifests as an opportunistic infection, primarily affecting individuals who are immunocompromised and susceptible to the infection. We present a case study of one patient with nephrotic syndrome and membranous nephropathy, who underwent treatment with prednisone and cyclosporine in 2016. In early 2017, the patient was diagnosed with a "fungal infection" and discontinued the use of cyclosporine. After one month of anti-infection therapy, a cranial magnetic resonance imaging scan showed multiple abscesses in the right temporal region. The diagnosis of nocardiosis was confirmed based on the presence of metastatic abscess masses, multiple lung and brain lesions, and a positive culture of Nocardia in the drainage. We changed the anti-infection therapy to a combination of trimethoprim-sulfamethoxazole (TMP-SMX), minocycline, and voriconazole. However, the patient experienced a sudden cardiac arrest and subsequently recovered after cardiopulmonary resuscitation. During the five-month follow-up period following the discharge, the patient displayed an enhanced nutritional status and stable renal function. The focal infection ultimately resolved during the subsequent three years. Neuro-infection caused by Nocardia should be considered in immunocompromised patients, and TMP-SMX is the preferred initial therapy; however, because of the high mortality rate, a long-term combination therapy with imipenem, cefotaxime, amikacin, and TMP-SMX is suggested.