Nocardia Research Articles

A case of cutaneous nocardiosis characterized by beaded enlarged lymph nodes on ultrasonography

A case of cutaneous nocardiosis characterized by beaded enlarged lymph nodes on ultrasonography

Successful Liver Retransplantation in a Patient With Disseminated Aspergillosis and Nocardiosis: A Case Report

Clinical guidelines list active fungal infection and sepsis as contraindications to liver transplantation due to the risk of worsening infection with immunosuppression postoperatively. Mortality from systemic opportunistic infections in transplant recipients is high, approaching 100% for disseminated aspergillosis. However, the optimal duration of treatment required before transplant is unclear. Additionally, delaying surgery while the infection is treated risks death from hepatic decompensation and physical deconditioning, preventing progression to transplantation. Here, we present a patient who underwent successful repeat liver transplantation for recurrent autoimmune hepatitis and graft rejection while undergoing treatment for disseminated aspergillosis and nocardiosis. He had pulmonary, hepatic, and central nervous system involvement. He had received 2 months of antimicrobials but had ongoing radiologic evidence of infection when listed for retransplantation. He remains well and infection-free 1 year postoperatively. Few cases of successful liver transplantation in the setting of disseminated aspergillosis have been reported previously. To our knowledge, this is the first successful liver transplant in a patient with disseminated nocardial infection.

Nocardiosis ‘great imitator’: unusual disease with usual presentations at unusual site

Nocardia, an aerobic actinomycete, typically affects immunosuppressed individuals, commonly manifesting in the lungs. Cutaneous infections, particularly by N. pseudobrasiliensis, can occur, presenting as lympho-cutaneous, superficial, or mycetoma subtypes. Nocardia farcinica, resistant to third-generation cephalosporins, is particularly virulent. A 50-year-old female with type 2 diabetes presented with painful nodules, bullae, and recurrent discharge over the left wrist, mimicking cellulitis. Culture-sensitivity revealed Nocardia farcinica. Treatment involved debridement, De quervain release and prolonged Linezolid therapy for a complete cure. Cutaneous Nocardiosis can mimic cellulitis, posing diagnostic challenges due to slow growth and microbiological detection. N. farcinica demonstrated resistance to conventional antibiotics. This case emphasizes the importance of considering Nocardia infections in diverse clinical presentations, highlighting the need for a comprehensive diagnostic approach, especially in immunocompromised individuals.

Invasive Nocardia Infections across Distinct Geographic Regions, United States.

Invasive Nocardia Infections across Distinct Geographic Regions, United States.

Clinical screening of Nocardia in sputum smears based on neural networks.

Nocardia is clinically rare but highly pathogenic in clinical practice. Due to the lack of Nocardia screening methods, Nocardia is often missed in diagnosis, leading to worsening the condition. Therefore, this paper proposes a Nocardia screening method based on neural networks, aiming at quick Nocardia detection in sputum specimens with low costs and thereby reducing the missed diagnosis rate. Firstly, sputum specimens were collected from patients who were infected with Nocardia, and a part of the specimens were mixed with new sputum specimens from patients without Nocardia infection to enhance the data diversity. Secondly, the specimens were converted into smears with Gram staining. Images were captured under a microscope and subsequently annotated by experts, creating two datasets. Thirdly, each dataset was divided into three subsets: the training set, the validation set and the test set. The training and validation sets were used for training networks, while the test set was used for evaluating the effeteness of the trained networks. Finally, a neural network model was trained on this dataset, with an image of Gram-stained sputum smear as input, this model determines the presence and locations of Nocardia instances within the image. After training, the detection network was evaluated on two datasets, resulting in classification accuracies of 97.3% and 98.3%, respectively. This network can identify Nocardia instances in about 24 milliseconds per image on a personal computer. The detection metrics of mAP50 on both datasets were 0.780 and 0.841, respectively. The Nocardia screening method can accurately and efficiently determine whether Nocardia exists in the images of Gram-stained sputum smears. Additionally, it can precisely locate the Nocardia instances, assisting doctors in confirming the presence of Nocardia.

2601. A 14-year retrospective study of pulmonary nocardiosis in AIDS patients, Northeastern Thailand

Abstract Background Nocardiosis is an opportunistic infection in immunocompromised individuals, particularly patients with acquired immune deficiency syndrome (AIDS). Clinical manifestations of nocardiosis are wide-ranging but the most common is pneumonia. Methods This 14 year retrospective study included Nocardia species infected adult patients (≥15 years) with at least 28 days of treatment follow-up. This study aims to compare clinical manifestations and survival analysis of cultured confirmed pulmonary nocardiosis among AIDS and non-AIDS patients. Results From 2009 to 2022, 237 patients had culture confirmed Nocardia species infection, of which 22 were excluded from this study because 13 had cutaneous nocardiosis and nine had pulmonary nocardiosis with follow-up less than 28 days. A total of 215 confirmed pulmonary nocardiosis were recruited to the analysis, 97(45.1%) were HIV-infected and 118 (54.9%) were non-HIV. All HIV-infected patient has CD4 count below 200 cell/mm3 (range 1-198, 1-15%), known as AIDS. Most of them were male with a mean age of 37 (range 15-83) years. One hundred fifty of the 215 (69.7%) patients underwent brain imaging. Sixteen cases (10.7%) had brain abscess. Disseminated nocardiosis (brain abscess, bacteremia, cutaneous abscess) was found in equal proportions in AIDS (15/97, 15.5%) and non-AIDS patients (17/118, 14.4%), while pulmonary nocardiosis with local invasion (empyema thoracis, pericardial effusion) was more common in AIDS (11/97, 11.3%) than non-AIDS patients (9/118, 7.6%). Overall and 28 days mortality were 116 (53.9%) and 88 (40.9%), respectively. In Cox’s proportional hazard analysis, AIDS was the independent factor associated with 28 days mortality in pulmonary nocardiosis (adjusted HR 2.62; 95%CI, 1.38 to 4.98) and those who underwent brain imaging (adjusted HR 2.75; 95%CI, 1.23 to 6.15) after adjusted by sex, age, duration of illness, respiratory failure, shock, multi-lobar pneumonia, disseminated nocardiosis, and combination antibiotic therapy. Conclusion Pulmonary nocardiosis is a serious opportunistic infection in AIDS patient and has shown significantly higher mortality than non-AIDS. Therefore, nocardiosis should always be considered as a cause of pneumonia in AIDS patients in order to prompt aggressive treatment. Disclosures Yupin Suputtamongkol, MD, Abbott Labs: Grant/Research Support|Abbott Labs: Mahidol University is partner in the Abbott Pandemic Defense Coalition

Diagnosis of cutaneous primary nocardiosis in patients with normal immune function by metagenomic next-generation sequencing.

Nocardia primarily affects immunocompromised individuals, and Infection with Nocardia is uncommon and primary cutaneous nocardiosis caused by percutaneous inoculation is even rarer. Primary cutaneous nocardiosis remains a diagnostic challenge and should be considered in the differential diagnosis for any superficial cutaneous infection that arises in patients with normal immune function. We report a case that was diagnosed with primary cutaneous Nocardia by metagenomic next-generation sequencing technology.

Clinical characteristics of hospitalized patients with Nocardia genus detection by metagenomic next generation sequencing in a tertiary hospital from southern China

ObjectiveAs an opportunistic pathogen, Nocardia often occurring in the immunocompromised hosts. As the unspecifc clinical presentation and low identification rate of the culture dependent methods, Nocardia infection may be under-diagnosis. Recent study have reported physicians could benefit from metagenomic next-generation sequencing (mNGS) in Nocardia diagnosis. Herein, we present patients with a positive detection of nocardiosis in mNGS, aiming to provide useful information for an differential diagnosis and patients management.MethodsA total of 3756 samples detected for mNGS from March 2019 to April 2022 at the Fifth Affifiliated Hospital of Sun Yat-sen University, were screened. Clinical records, laboratory finding, CT images and mNGS results were reviewed for 19 patients who were positive for Nocardia genus.ResultsSamples from low respiratory tract obtained by bronchoscope took the major part of the positive (15/19). 12 of 19 cases were diagnosis as Nocardiosis Disease (ND) and over half of the ND individuals (7/12) were geriatric. Nearly all of them (10/12) were immunocompetent and 2 patients in ND group were impressively asymptomatic. Cough was the most common symptom. Nocardia cyriacigeorgica (4/12) was more frequently occurring in ND, followed by Nocardia abscessus (3/12). There are 3 individuals detected more than one kind of Nocardia species (Supplementary table 1). Except one with renal failure and one allergic to sulfamethoxazole, all of them received co-sulfonamide treatment and relieved eventually.ConclusionOur study deciphered the clinical features of patients with positive nocardiosis detected by mNGS. Greater attention should be paid to the ND that occurred in the immunocompetent host and the geriatric. Due to the difficulties in establishing diagnosis of Nocardiosis disease, mNGS should play a much more essential role for a better assessment in those intractable cases. Co-sulfonamide treatment should still be the first choice of Nocardiosis disease.

Gastrointestinal dysbiosis induced by Nocardia sp. infection in tilapia

Nocardiosis has caused high mortalities among fish cultures; however, the effects of Nocardia infections in the fish gastrointestinal microbiota are unknown. In this research, tilapia was infected with Nocardia sp., to analyze the effect of infection on the gastrointestinal microbiota. Tilapia infected with Nocardia sp. reported a 46 % survival (100 % in non-infected). Moreover, the infection caused severe damage to the stomach microbiota, with a loss of diversity and a significant increase of Proteobacteria (94.8 %), resulting in a negative correlation network between Proteobacteria and other important phyla. Nocardia sp. is an emerging pathogen capable of inducing dysbiosis and causing significant mortalities.

A case of cutaneous nocardiosis successfully treated with third-generation cephalosporin

A case of cutaneous nocardiosis successfully treated with third-generation cephalosporin

A Clinical Model to Predict the Occurrence of Select High-risk Infections in the First Year Following Heart Transplantation.

Invasive infection remains a dangerous complication of heart transplantation (HT). No objectively defined set of clinical risk factors has been established to reliably predict infection in HT. The aim of this study was to develop a clinical prediction model for use at 1 mo post-HT to predict serious infection by 1 y. A retrospective cohort study of HT recipients (2000-2018) was performed. The composite endpoint included cytomegalovirus (CMV), herpes simplex or varicella zoster virus infection, blood stream infection, invasive fungal, or nocardial infection occurring 1 mo to 1 y post-HT. A least absolute shrinkage and selection operator regression model was constructed using 10 candidate variables. A concordance statistic, calibration curve, and mean calibration error were calculated. A scoring system was derived for ease of clinical application. Three hundred seventy-five patients were analyzed; 93 patients experienced an outcome event. All variables remained in the final model: aged 55 y or above, history of diabetes, need for renal replacement therapy in first month, CMV risk derived from donor and recipient serology, use of induction and/or early lymphodepleting therapy in the first month, use of trimethoprim-sulfamethoxazole prophylaxis at 1 mo, lymphocyte count under 0.75 × 103cells/µL at 1 mo, and inpatient status at 1 mo. Good discrimination (C-index 0.80) and calibration (mean absolute calibration error 3.6%) were demonstrated. This model synthesizes multiple highly relevant clinical parameters, available at 1 mo post-HT, into a unified, objective, and clinically useful prediction tool for occurrence of serious infection by 1 y post-HT.

28 A case of cutaneous nocardiosis misdiagnosed as tuberculosis

28 A case of cutaneous nocardiosis misdiagnosed as tuberculosis

Nocardia paucivorans Endophthalmitis and Cerebral Abscesses in an Immunocompetent Patient

Abstract Nocardia spp are an uncommon cause of central nervous system infections and particularly endophthalmitis. In this case report, we present the first documented case of endogenous Nocardia paucivorans endophthalmitis and subretinal abscesses. We also provide a brief summary of the literature regarding ocular and cerebral nocardiosis. Early diagnosis and management improve outcomes; hence, clinicians should be cognizant of Nocardia infection as a differential diagnosis in cases of cerebral abscess or endophthalmitis, including in the immunocompetent.

Primary Cutaneous Nocardiosis due to Nocardia asteroides Presenting as Mycetoma of Back in an Immunocompetent Patient: A Rare Presentation.

Primary Cutaneous Nocardiosis due to Nocardia asteroides Presenting as Mycetoma of Back in an Immunocompetent Patient: A Rare Presentation.

A Case of Cutaneous Nocardiosis Accompanied with COVID-19 Infection

A Case of Cutaneous Nocardiosis Accompanied with COVID-19 Infection

Infections in autoimmune pulmonary alveolar proteinosis: a large retrospective cohort

BackgroundAutoimmune pulmonary alveolar proteinosis (aPAP) is a rare disease, predisposing to an increased risk of infection. A complete picture of these infections is lacking.Research questionDescribe the characteristics and clinical outcomes...

Nocardia Brain Abscess In A Patient With Advanced HIV-AIDS: Case Report

Nocardia is a gram-positive bacterium that causes localised and disseminated infections. A rare case of Nocardia infection in an immunocompromised individual is presented. Nocardiosis should be kept in mind as a diagnosis in immunocompromised patients with a solitary space occupying lesion in the brain.

Pairing comparative genomics with tandem mass-based molecular networking allows to highly efficient discovery of nonribosomal peptides from Nocardia spp.

Microbial natural products, particularly nonribosomal peptides (NRPs), have attracted significant attention due to their structural diversity and therapeutic potential. Nocardia, a genus of Actinomyces, is an important reservoir for natural products, especially NRPs. However, rediscovery is a significant challenge for mining new specialized metabolites from Nocardia, as well as from other sources. To overcome this challenge, we developed a strategy that combines comparative genomics with tandem mass-based molecular networking, which allows to efficiently discover new NRPs from Nocardia spp.. As a proof of concept, all genomes of Norcardia in NCBI database, including three strains from our lab, were compared with each other to prioritize unique biosynthetic gene clusters (BGCs) in the three in-house Nocardia strains, particularly those containing nonribosomal peptide synthases (NRPSs). Subsequently, the metabolomics data of those three in-house strains were analyzed employing tandem mass-based molecular networking. This led to the identification of a known lipopeptide, nocarjamide (1), and five new congeners (2-6) of nocarjamide, as well as a new decalipopeptide, nocarlipoamide (7), along with nocardimicin, a known compound found in Nocardia. The structure of the new decalipopeptide 7 was further extensively characterized using NMR, MS/MS, Marfey's analysis, and X-ray. In addition, the biosynthesis pathways for 1-7 were proposed through bioinformatics analysis, and thus the gene clusters responsible for biosynthesizing them were confirmed. Our results indicate that this strategy enables prompt dereplication of known compounds, rapid linkage of identified compounds with their biosynthesis gene cluster, and efficient discovery of new compounds.

Nocardiosis: a single-center experience and literature review.

Nocardiosis is a rare bacterial infection caused by Nocardia spp. However, anincreasingincidence has been described whereby data about epidemiology and prognosis are essential. A retrospective descriptive study was conducted among patients with positive Nocardia spp. culture, from January2019 to January2023, at a Terciary Hospital in Portugal. Nocardiosis was considered in18cases with a median age of63.8-years-old. At least one immunosuppressive cause was identified in70% of patients. Five patients had Disseminated Nocardiosis (DN). The lung was the most common site of clinical disease (77.8%) and Nocardia was most commonly identified in respiratory tract samples. The most frequently isolated species were Nocardia nova/africana (n=7) followed by Nocardia cyriacigeorgica (n=3) and Nocardia pseudobrasiliensis (n=3). The majority of the patients (94.4%) received antibiotic therapy, of whom as many as55.6% were treated with monotherapy. The most frequently prescribed antibiotic was trimethoprim-sulfamethoxazole. Selected antimicrobial agents were generally effective, with linezolid and cotrimoxazole(100%Susceptibility [S]) and amikacin(94% S) having the most activity againstNocardiaspecies. The median (IQR) duration of treatment was 24.2 (1‒51.4) weeks for DN; The overall one-year case fatality was 33.3% (n=6) and was higher in the DN (66.7%). No recurrence was observed. Nocardiosis is an emerging infectious disease with a poor prognosis, particularly in DN. This review offers essential epidemiological insights and underscores the importance of gaining a better understanding of the microbiology of nocardiosis. Such knowledge can lead to the optimization of antimicrobial therapy and, when necessary, guide appropriate surgical interventions to prevent unfavorable outcomes.

Clinical and microbiological characteristics ofnocardiosis: A 5-year single-center study inCrete, Greece.

Nocardiosis is a rare disease affecting both immunocompromised and immunocompetent hosts, presented in various clinical forms ranging from localized to disseminated infection. Aim of the present study was to investigate the clinical and microbiological characteristics of nocardiosis, antimicrobial resistance profiles, treatment, and outcomes of Nocardia infection over the last 5 years at our institution. The medical records and microbiological data of patients affected by nocardiosis and treated at the university hospital of Heraklion, Crete, Greece, between 2018 and 2022, were retrospectively analyzed. The isolates were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and through sequencing of 16S rRNA. Antimicrobial susceptibility for 17 agents was determined by E-test and results were interpreted according to CLSI guidelines. Among the 28 Nocardia isolates, eight species were identified, with Nocardia brasiliensis being the most prevalent (32.1%), followed by Nocardia otitidiscaviarum (25%), and Nocardia farcinica (14.3%). Skin and soft tissue infections were the most common presentations, noted in 13 (50%) patients, followed by pulmonaryinfection presented in 10 (38.5%) patients. Fifteen patients (57.7%) had at least one underlying disease, and 11 (42.3%) were on immunosuppressive or long-term corticosteroid treatment. Susceptibility rates of linezolid, tigecycline, amikacin, trimethoprim-sulfamethoxazole, moxifloxacin, and imipenem were 100, 100, 96.4, 92.9, 82.1, and 42.9%, respectively. The 26 patients in this study were treated with various antibiotics. Mortality rate was 3.8%, and the patient who died had disseminated infection. Since epidemiology and antimicrobial susceptibility are evolving, continuous surveillance is mandatory in order to initiate appropriate treatment in a timely manner.