Search

Nocardia is a rare cause of ocular infections and most commonly occurs secondary to trauma. Systemic Nocardiosis may have ocular involvement in rare cases. We report a case of disseminated nocardiosis with orbital apex involvement and endophthalmitis in an immunocompromised patient. The patient presented with respiratory sepsis, and later developed complete ptosis and ophthalmoplegia in the left eye. This was on the background of treatment with high-dose prednisolone. Magnetic resonance imaging showed enhancement of the entire clivus, extending into the left orbital apex and cavernous sinus. The patient was initially treated empirically for CNS tuberculosis. Bronchoscopic cultures returned positive for Nocardia farcinica, and the patient was treated with trimethoprim/sulfamethoxazole and weaned off previous corticosteroids. [ABSTRACT FROM AUTHOR]

Background: Nocardia infections are rare infections in immunocompetent patients and occur mostly in immunocompromised individuals. Usually, nocardia affects skin, brain, and lungs, but in disseminated forms, which occurred mostly in immunocompromised patients, it can involve every organ. Nocardia sinusitis is extremely rare as our searches returned only a very few related studies. Case presentation: In this case report, we present, for the first time, a 55-year-old Iranian male patient diagnosed with chronic lymphocytic leukemia who was receiving chemotherapeutic drugs and developed a fever. Further laboratory tests and imaging revealed pansinusitis. Following rhinoendoscopy, the sinus mucosal biopsy pathology report showed sever inflammation accompanied by aggregation of filamentous thin-walled bacteria. The patient was treated with co-trimoxazole and meropenem. Following good clinical improvement the patient was discharged and advised to continue oral co-trimoxazole for 3 months. Conclusion: This case highlights that patients with febrile neutropenia should be assessed for rare infectious disease etiologies, especially those with chronic lymphocytic leukemia, as they have humeral immunodeficiency, and in the later stages of the disease, cellular immunodeficiency may also be involved. Therefore, a multisystem evaluation of patients with febrile neutropenia is necessary, particulary when no obvious source is identified in initial surveys, to uncover rare etiologies. [ABSTRACT FROM AUTHOR]

Background: Nocardia are widely present in nature and considered opportunistic pathogens. They can result in hematogenous spread infection through the ruptured skin or respiratory tract when the host's immune system is compromised. Currently, 119 species of Nocardia have been identified, with 54 capable of causing infections in humans. Nocardial brain abscesses are a rare intracranial lesion that accounts for only 2% of all brain abscesses, but have a mortality rate of 20–55%. This article reports a successfully cured case of mediastinal Nocardia infection with disseminated brain abscess. Case presentation: The patient presented with intermittent chills, shivering, and fever, with the highest temperature of 39˚C, accompanied by shoulder and back pain, dizziness, and headaches. A chest-enhanced computed tomography (CT) revealed multiple enhanced nodulars in the bilateral hilum and mediastinum. A head-enhanced CT revealed scattered multiple ring-enhanced nodules in both cerebral hemispheres and the left cerebrum, accompanied by extensive surrounding edema. The mediastinal puncture tissue culture confirmed the growth of Nocardia. After twice discussions with multidisciplinary team (MDT) to rule out the possibility of mediastinal and intracranial metastatic tumors, we promptly initiated treatment with a triple-drug antibiotic regimen consisting of imipenem/cilastatin sodium, linezolid dextrose, and Trimethoprim-sulfamethoxazole (TMP-SMX). The patient ultimately achieved complete remission. Conclusions: Mediastinal nocardiosis with disseminated brain abscesses is a rare condition that can be difficult to differentiate from brain metastases caused by lung cancer. Bacterial culture results, imaging features, and MDT discussions are crucial for accurate diagnosis and treatment. A triple-drug antibiotic regimen has been found to be effective in treatment with acceptable levels of toxicity. [ABSTRACT FROM AUTHOR]

Background: Nocardiosis is an opportunistic infection that has a low prevalence rate, its clinical manifestations are atypical and can be easily misdiagnosed as other diseases. The correct diagnosis and treatment are frequently delayed by various factors. In this case report, we present a pediatric patient with Neuromyelitis Optica Spectrum Disorders who developed Nocardia farcinica pneumonia complicated by pneumocystis jiroveci infection. Case presentation: An 8-year-old girl with chest pain and cough was admitted to the hospital. She suffered from Neuromyelitis Optica Spectrum Disorders and had been taking methylprednisolone and tacrolimus orally for 3 years. She was admitted to the hospital for tests and was diagnosed with acute pneumonia. Despite empiric antibiotic treatment, her condition gradually worsened. Respiratory distress developed, and she needed to use a ventilator for breathing. The symptoms she exhibited led us to suspect the presence of a tumor. Etiological tests later confirmed the co-infection of Nocardia farcinica and Pneumocystis jiroveci. After treatment, the child's lung infection eventually resolved. Conclusion: The Nocardia bacteria and Pneumocystis jiroveci are widely distributed in the environment, possess the capability of systemic dissemination, and exhibit significant resistance to specific treatments. Invasive sampling is frequently necessary for confirming their presence. Timely and accurate diagnosis as well as treatment play a crucial role in patient survival. [ABSTRACT FROM AUTHOR]

The zoonosis caused by Nocardia is increasing seriously. But commonly used antibiotic drugs often lead to resistance. N. seriolae dUTPase (NsdUTPase) plays a key role in the proliferation of Nocardia, and was regarded as a potent drug target. However, there was little report about the NsdUTPase inhibitors. In this study, we discovered a series of novel NsdUTPase inhibitors to fight against Nocardia. The first crystal structure of NsdUTPase was released, and a structure-based computational design was performed. Compounds 4b and 12b exhibited promising activities towards NsdUTPase (IC50 = 0.99 μM and 0.7 μM). In addition, they showed satisfied anti-Nocardia activity (MIC value ranges from 0.5 to 2 mg/L) and low cytotoxicity, which were better than approved drugs oxytetracycline and florfenicol. Molecular modelling study indicated that hydrophobic interaction might be the main contribution for ligand binding. Our results suggested that NsdUTPase inhibitors might be a useful way to repress Nocardia. [ABSTRACT FROM AUTHOR]

The typical clinical signs of Nocardia seriolae infection include white nodules, ranging from 0.1 to 10 mm in diameter, distributed across various internal organs. However, the structural composition of nodules of different sizes remains unexplored. In this study, natural cases of largemouth bass (Micropterus salmoides) were collected, and pathogenic bacteria were isolated and confirmed through a re-infection experiment. The isolated bacteria were identified as N. seriolae through 16S rRNA and gyrB gene sequencing. Healthy largemouth bass were infected with the isolate using an immersion infection and observed continuously over 56 days. Samples were successfully obtained from the incubation, prodromal, symptomatic, and convalescent phases, allowing for gross, histological, and ultrastructural observations of nodular lesion progression. Results demonstrated two types of nodular lesions: necrotic foci and granulomas. Macroscopically visible nodules larger than 1 mm, observed primarily in the liver, spleen, kidney, and muscle tissues of moribund fish, exhibited coagulative necrosis and were identified as the principal cause of mortality. Conversely, granulomas, with diameters less than 1 mm, were consistently present in the spleen, kidney, and liver during the symptomatic and convalescent phases. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Nocardiosis is a rare infectious disease, which is frequently underdiagnosed because of the distinct bacterial shape of the causative agent and its developmental history. The morphological analysis of bronchoalveolar lavage fluid can facilitate the detection of pathogenic bacteria by observing cellular–bacterial interactions. Case presentation: An immunocompetent 67-year-old male patient of Asian ethnicity developed a cough without apparent cause 20 days earlier. We initially discovered mycobacteria that appeared to be Nocardia in the cytomorphological examination of bronchoalveolar lavage fluid, which was later determined to be Nocardia otitidiscaviarum through metagenomic next-generation sequencing and microbiological cultures. The patient was eventually diagnosed with Nocardia pneumonitis after other testing and clinical signs were considered. After anti-infective treatment, the patient improved and was discharged. Conclusion: Several diagnostic approaches were used in this case, and the importance of cell morphology as an early screening method was emphasized for suspected Nocardia infection. [ABSTRACT FROM AUTHOR]

N. neocaledoniensis is a very rare infectious pathogen that causes human disease, particularly in immunocompromised individuals. In this case report, we describe the successful diagnosis of N. neocaledoniensis in a patient confirmed by mNGS and the treatment of multiple skin abscesses due to N. neocaledoniensis infection. mNGS is an important diagnostic method complementary to routine bacterial culture and identification methods, especially for rare, novel, co-infected pathogens, and pathogens that are difficult to culture. This report may provide a reference for the clinical treatment and diagnosis of N. neocaledoniensis infection in humans. [ABSTRACT FROM AUTHOR]

Nocardiosis is a collective term for tissue and organ damage caused by Nocardia infection. Solid organ transplant recipients (SOTR) are at an increased risk of various pathogen infections, including Nocardia infection, due to immunosuppressive therapy which weakens their immune function. The diagnosis of nocardiosis has been challenging in the past. With the advent of molecular biology and other diagnostic methods, the diagnostic rate has significantly improved. Nocardia not only prone to cause necrotic pulmonary lesions but also invade other organs and tissues, such as intracranial infections and skin soft tissue infections, and can develop into systemic disseminated infections. For SOTR, nocardiosis is a potentially fatal disease with a fatality as high as 30%. Therefore, this article reviews the clinical characteristics of common nocardiosis in SOTR, new diagnostic technologies, and different anti-infective treatment strategies, aiming to provide a reference for the prevention and treatment of nocardiosis in clinical SOTR. [ABSTRACT FROM AUTHOR]

Nocardia farcinica is the most pathogenic Nocardia, which is easy to disseminate. It can be caused by trauma, and even lead to severe lung or central nervous system infection. This report covers a case of Nocardia brain abscess in an HIV patient, who underwent resection of the brain abscess, followed by anti-infective therapy with sulfamethoxazole and meropenem, and eventually made a good recovery. The mortality rate of Nocardia farcinica brain abscess has been attributed to the severity of the underlying disease, the difficulty in identifying the pathogen, and its inherent resistance to antibiotics, leading to inappropriate or late initiation of treatment. Medication should follow the principle of sufficient dosage and sufficient course of treatment. [ABSTRACT FROM AUTHOR]

Yellow nail syndrome (YNS) is a rare clinical syndrome characterized by nail bed changes, pulmonary involvement, and lymphatic drainage disorders. Pulmonary involvement usually manifests as bronchiectasis, bronchiolitis, and pleural effusion. There are few studies on yellow nail syndrome combined with opportunistic infection. Here, we report a case of clinically diagnosed YNS combined with Nocardia cyriacigeorgica infection and the course of treatment used, which can provide some useful information for clinicians to better understand this rare illness. [ABSTRACT FROM AUTHOR]

Mycetoma is currently considered as a neglected tropical disease. The incidence of mycetoma is unknown but most of the worldwide cases are present in the "mycetoma belt" including countries like Mexico, India, Senegal, and others. The treatment of mycetoma depends on the etiological agent responsible for the case. Treatment success reaches 60 to 90%; however, common treatment has been reported to be ineffective in some cases, due in part to resistance to the prescribed antibiotics. Therefore, it is necessary to develop new therapeutic options. In the past two decades, quinoxaline derivatives have shown relevance as antibacterial agents. Therefore, in this work, esters of quinoxaline 1,4-di-N-oxide derivatives were evaluated in vitro against the reference strain CECT-3052 from N. brasiliensis, six clinical isolates, and macrophages J774A.1 to determine their cytotoxicity and security index. Additionally, nine reference drugs were evaluated as controls. The results show that nine esters of quinoxaline 1,4-di-N-oxide derivatives had a minimum inhibitory concentration (MIC) < 1 µg/mL against the reference strain and four of them (N-05, N-09, N-11, and N-13) had an MIC < 1 µg/mL against the clinical isolates. Therefore, the scaffold quinoxaline 1,4-di-N-oxide could be used to develop new and more potent antinocardial agents. [ABSTRACT FROM AUTHOR]

The article discusses the impact of sulfonamide allergy labels on the risk of opportunistic infections after solid organ transplantation (SOT). SOT recipients with a sulfonamide allergy label were found to have an increased risk of Toxoplasma and Nocardia infections compared to those without the label. The study highlights the importance of reassessing sulfonamide allergy labels in SOT recipients to optimize prophylactic treatment and reduce the risk of opportunistic infections. Efforts should be made to identify safe delabeling strategies and promote the use of trimethoprim/sulfamethoxazole (TMP‐SMX) in eligible SOT recipients. [Extracted from the article]

The silkworm Nocardia infection model has been established as a useful animal model for screening the pathogenicity of Nocardia and evaluating the therapeutic effects of antimicrobial agents against Nocardia infection. No histopathological analysis of silkworms infected with Nocardia farcinica has yet been performed. In this study, we performed histological analyses on organs of silkworms infected with N. farcinica. One day after infection with N. farcinica, the organism developed a branching filamentous form from coccid cells in the hemolymph. In addition, we evaluated effective doses (ED50) values by treating infected silkworms with amikacin 30 seconds and 24 hours after infection and found that the ED50 values treated within 30 seconds and 24 hours after infection were 4.1 µg/larva and 5.6 µg/larva, respectively. Evaluation of treatment with amikacin against the infected silkworms was unaffected by the growth process form of Nocardia. These results suggest that the silkworm Nocardia infection model is a useful tool for evaluating the antimicrobial therapy in the growth process of the N. farcinica. [ABSTRACT FROM AUTHOR]

Background: Nocardia, a rare but potentially fatal pathogen, can induce systemic infections with diverse manifestations. This study aimed to investigate the tissue and organ damage caused by Nocardia farcinica (N. farcinica) in mice via different infection routes, evaluate the resulting host immune responses, and assess its invasiveness in brain tissue. Methods: BALB/c mice were infected with N. farcinica through intranasal, intraperitoneal, and intravenous routes (doses: 1 × 10^8, 1 × 10^7, 1 × 10^7 CFU in 50 µl PBS). Over a 7-day period, body temperature, weight, and mortality were monitored, and samples were collected for histopathological analysis and bacterial load assessment. Serum was isolated for cytokine detection via ELISA. For RNA-seq analysis, mice were infected with 1 × 107 CFU through three infection routes, after which brain tissue was harvested. Results: Intraperitoneal and intravenous N. farcinica infections caused significant clinical symptoms, mortality, and neural disruption in mice, resulting in severe systemic infection. Conversely, intranasal infection primarily affected the lungs without causing significant damage to other organs. Intraperitoneal and intravenous infections significantly increased serum cytokines, particularly TNF-α and IFN-γ. RNA-seq analysis of brains from intravenously infected mice revealed significant differential gene expression, whereas the intranasal and intraperitoneal routes showed limited differences (only three genes). The enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways in the intravenous group were primarily related to immune processes. Conclusion: The study demonstrated that intravenous N. farcinica infection induces significant clinical symptoms, triggers an inflammatory response, damages multiple organs, and leads to systemic infections. [ABSTRACT FROM AUTHOR]

Background: Nocardiosis, despite its rarity and underreporting, is significant due to its severe impact, characterized by high morbidity and mortality rates. The development of a precise, reliable, rapid, and straightforward technique for identifying the pathogenic agent in clinical specimens is crucial to reduce fatality rates and facilitate timely antimicrobial treatment. In this study, we aimed to identify Nocardia spp. in clinical isolates, using MALDI-TOF MS as the primary method, with molecular methods as the gold standard. Clinical Nocardia isolates were identified using 16S rRNA/hsp65/gyrB/secA1/rpoB gene sequencing. Identification performance of the Bruker MALDI Biotyper 3.1 (V09.0.0.0_8468) and MBT Compass 4.1 (V11.0.0.0_10833) for Nocardia identification was evaluated. Results: Seventy-six Nocardia isolates were classified into 12 species through gene sequencing. The MALDI Biotyper 3.1 (V09.0.0.0_8468) achieved 100% genus-level accuracy and 84.2% species accuracy (64/76). The MBT Compass 4.1 with the BDAL Database (V11.0.0.0_10833) improved species identification to 98.7% (75/76). The updated database enhanced species level identification with scores > 1.7, increasing from 77.6% (59/76) to 94.7% (72/76), a significant improvement (P = 0.001). The new and simplified extraction increased the proportion of strains identified to the species level with scores > 1.7 from 62.0% (18/29) to 86.2% (25/29) (P = 0.016). An in-house library construction ensured accurate species identification for all isolates. Conclusions: The Bruker mass spectrometer can accurately identify Nocardia species, albeit with some variations observed between different database versions. The MALDI Biotyper 3.1 (V09.0.0.0_8468) has limitations in identifying Nocardia brasiliensis, with some strains only identifiable to the genus level. MBT Compass 4.1 (V11.0.0.0_10833) effectively addresses this shortfall, improving species identification accuracy to 98.7%, and offering quick and reliable identification of Nocardia. Both database versions incorrectly identified the clinically less common Nocardia sputorum as Nocardia araoensis. For laboratories that have not upgraded their databases and are unable to achieve satisfactory identification results for Nocardia, employing the new and simplified extraction method can provide a degree of improvement in identification outcomes. [ABSTRACT FROM AUTHOR]

Nocardia is widely distributed in the natural environment and typically cause opportunistic infections. However, it is important to note that the pathogenicity of different Nocardia species may vary significantly. Here we reported the first case of brain abscess caused by Nocardia beijingensis (N. beijingensis) infection in China. A 70-year-old male immunocompetent individual came to our hospital for treatment due to headache. After examination, it was found that he had a brain abscess caused by N. beijingensis. By utilizing a combination of surgical intervention and antibiotic therapy, the patient ultimately achieved full recovery. In addition, we isolated this strain and displayed its ultrastructure through scanning electron microscopy. The phylogenetic tree was analyzed by 16 S rRNA sequence. A literature review of N. beijingensis infections in all immunocompetent and immunocompromised patients was presented. It highlighted that abscess formation appears to be a common manifestation of N. beijingensis infection, and N. beijingensis has become an emerging pathogen in immunocompetent individuals. [ABSTRACT FROM AUTHOR]

The identification of specialized metabolites isolated from microorganisms is urgently needed to determine their roles in treating cancer and controlling multidrug-resistant pathogens. Naphthoquinones act as anticancer agents in various types of cancers, but some toxicity indicators have been limited in their appropriate application. In this context, new isofuranonaphthoquinones (ifnq) that are less toxic to humans could be promising lead compounds for developing anticancer drugs. The aim of this study is to identify and characterize novel furanonaphthoquinones (fnqs) from Nocardia sp. CS682 and to evaluate their potential therapeutic applications. Analysis of the genome of Nocardia sp. CS682 revealed the presence of a furanonaphthoquinone (fnq) gene cluster, which displays a similar genetic organization and high nucleotide sequence identity to the ifnq gene cluster from Streptomyces sp. RI-77, a producer of the naphthoquinones JBIR-76 and JBIR-77. In this study, the overexpression of the Streptomyces antibiotic regulatory protein (SARP) in Nocardia sp. CS682DR (nargenicin gene-deleted mutant) explicitly produced new fnqs, namely, NOC-IBR1 and NOC-IBR2. Subsequently, the role of the SARP regulator was confirmed by gene inactivation using CRISPR-Cas9 and complementation studies. Furthermore, antioxidant, antimicrobial, and cytotoxicity assays were performed for the isolated compounds, and it was found that NOC-IBR2 exhibited superior activities to NOC-IBR1. In addition, a flexible methyltransferase substrate, ThnM3, was found to be involved in terminal methylation of NOC-IBR1, which was confirmed by in vitro enzyme assays. Thus, this study supports the importance of genome mining and genome editing approaches for exploring new specialized metabolites in a rare actinomycete called Nocardia. [ABSTRACT FROM AUTHOR]

Soil-dwelling Actinomycetes are a diverse and ubiquitous component of the global microbiome but largely lack genetic tools comparable to those available in model species such as Escherichia coli or Pseudomonas putida, posing a fundamental barrier to their characterization and utilization as hosts for biotechnology. To address this, we have developed a modular plasmid assembly framework, along with a series of genetic control elements for the previously genetically intractable Gram-positive environmental isolate Rhodococcus ruber C208, and demonstrate conserved functionality in 11 additional environmental isolates of Rhodococcus, Nocardia, and Gordonia. This toolkit encompasses five Mycobacteriale origins of replication, five broad-host-range antibiotic resistance markers, transcriptional and translational control elements, fluorescent reporters, a tetracycline-inducible system, and a counter-selectable marker. We use this toolkit to interrogate the carotenoid biosynthesis pathway in Rhodococcus erythropolis N9T-4, a weakly carotenogenic environmental isolate and engineer higher pathway flux toward the keto-carotenoid canthaxanthin. This work establishes several new genetic tools for environmental Mycobacteriales and provides a synthetic biology framework to support the design of complex genetic circuits in these species. [ABSTRACT FROM AUTHOR]

Objective To analyze the clinical characteristics of pulmonary tuberculosis patients complicated with infection of Nocardia farcinica aiming to improve the diagnosis and treatment the disease. Methods The clinical data of 22 cases of pulmonary tuberculosis complicated with Nocardia farcinica infection admitted to Guangzhou Chest Hospital from June 2020 to December 2023 were collected and the clinical manifestations, imaging, laboratory tests, treatment process, and disease outcomes were retrospectively analyzed. Results Among the 22 patients, there were 13 males and 9 females, aged 20 - 86 years, with a median age of 52 years. Common clinical manifestations included cough (22/22), sputum (21/22), and underlying diseases (13/22) . One case was positive for cerebrospinal fluid culture, and 21 cases were positive for sputum culture. The culture period was 5 - 26 days, with a median culture period of 18 days. The imaging manifestations were mainly plaques, plaques and cavities, and the lesions were spread in both lungs (17/22) and cavities (11/22) . After anti-tuberculosis treatment, the absorption of lung lesions in some patients was poor, and the absorption of the lesions was improved after anti-nocardia treatment. 8 cases were cured, 13 cases were improved and 1 case died. Conclusion The clinical symptoms of patients with pulmonary tuberculosis complicated with Nocardia farcinica were atypical, the culture period of Nocardia was long, and the imaging manifestations were similar to pulmonary tuberculosis, which is prone to misdiagnosis and missed diagnosis. For patients with poor response to anti-tuberculosis treatment and slow lesion absorption, the possibility of a concurrent Nocardia infection should be considered. [ABSTRACT FROM AUTHOR]

Nocardiosis is a rare systemic infection caused by aerobic, Gram-positive filamentous bacteria that belong to the genus Nocardia , typically affecting immunocompromised individuals but can also manifest in immunocompetent people. We report a case of pulmonary nocardiosis caused by Nocardia arthritidis in a 56-year-old female with a history of recurrent respiratory illness. The patient presented with a persistent cough, on-and-off fever, and a history of pulmonary tuberculosis. Sputum analysis revealed Gram-positive beaded branching filamentous bacilli, confirmed as N. arthritidis through molecular methods. Treatment with cotrimoxazole and ceftriaxone led to symptomatic improvement. [ABSTRACT FROM AUTHOR]

Currently, heavy metal-resistant (HMR) marine actinomycetes have attracted much attention worldwide due to their unique capabilities. In this study, 27 marine-derived actinomycetes were isolated from coastal beaches in the Arabian Gulf of Al-Jubail in Saudi Arabia and screened for resistance to 100 mg/L of the heavy metals Cd2+, Cr6+, Cu2+, Fe2+, Pb2+, and Ni2+ using different assay techniques. Six isolates were selected as HMRs, of which two isolates, JJB5 and JJB11, exhibited the highest maximum tolerance concentrations (200– > 300 mg/L). Both isolates were the highest among six-HMR screened for their biodegradation potential of plastics low-density polyethylene, polystyrene, and polyvinyl chloride, recording the highest weight loss (15 ± 1.22 – 65 ± 1.2%) in their thin films. They also showed the highest biodegradability of the pesticides acetamiprid, chlordane, hexachlorocyclohexane, indoxacarb and lindane, indicating promising removal capacities (95.70–100%) for acetamiprid and indoxacarb using HPLC analysis. Additionally, the cell-free filtrate (CFF) of both isolates displayed the highest antimicrobial activity among the six-HMR screened against a variety of microbial test strains, recording the highest inhibition zone diameters (13.76 ± 0.66 – 26.0 ± 1.13 mm). GC‒MS analyses of the ethyl acetate extract of their CFFs revealed the presence of diverse chemical compounds with a multitude of remarkable biological activities. Based on their spore morphology and wall-chemotype, they were assigned to the nocardioform-actinomycetes. Furthermore, their phenotypic characteristics, together with 16S rRNA gene sequencing (OR121525-OR121526), revealed them as Nocardia harenae JJB5 and Amycolatopsis marina JJB11. Our results suggest that marine HMR actinomycetes are promising candidates for various biotechnological applications. [ABSTRACT FROM AUTHOR]

Nocardiosis, caused by Nocardia seriolae, has been a prominent disease in Southeast Asian aquaculture in the last three decades. This granulomatous disease reported in various fish species is responsible for significant economic losses. This study investigated the pathogenicity of N. seriolae in three cultured species in Taiwan: Nile tilapia (omnivore), milkfish (herbivore) and Asian seabass (carnivore). Administration of an infective dose of 1 × 106 CFU/ fish in tilapia, seabass and milkfish demonstrated mortalities of 100%, 90% and 75%, respectively. Additionally, clinical signs namely, granuloma and lesions displayed varying intensities between the groups and pathological scores. Polymerase chain reaction (PCR) amplification specific for N. seriolae was confirmed to be positive (432 bp) using NS1/NG1 primers. Post‐mortem lesions revealed the absence of granulomas in tilapia and milkfish and their presence in the seabass. Interestingly, the gut in tilapia showed an influx of eosinophils suggesting its role during the acute stages of infection. However, post‐challenge, surviving milkfish exhibited granulomatous formations, while surviving seabass progressed toward healing and tissue repair within sampled tissues. Overall, in conclusion, these results demonstrate the versatility in the immunological ability of individual Perciformes to contain this pathogen as a crucial factor that influences its degree of susceptibility. [ABSTRACT FROM AUTHOR]

Background: Nocardia species can affect both immunocompetent and immunocompromised people. Method: 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. Results: 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)). Conclusion: 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. [ABSTRACT FROM AUTHOR]

Background: 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. Case presentation: 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. Conclusions: 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. [ABSTRACT FROM AUTHOR]

The Non-tuberculous mycobacterial (NTM) isolates should be distinguished from tuberculosis and identified at the species level for choosing an appropriate treatment plan. In this study, two molecular methods were used to differentiate NTM species, including a new designed High Resolution Melting (HRM) and Multilocus Sequence Analysis (MLSA). Seventy-five mycobacterial isolates were evaluated by sequencing four genes (MLSA) and a HRM assay specifically targeting atpE was designed to rapidly and accurately identify and differentiate mycobacterium species. Out of 70 NTM isolates, 66 (94.3%), 65 (92.9%), 65 (92.9%) and 64 (91.4%) isolates were identified to the species level by PCR of atpE, tuf, rpoB and dnaK genes. We could identify 100% of the isolates to the species level (14 different species) by MLSA. By using HRM assay, all NTM isolates were identified and classified into eight groups, in addition, Mycobacterium tuberculosis and Nocardia were also detected simultaneously. The MLSA technique was able to differentiate all 14 species of NTM isolates. According to the results, the HRM assay is a rapid and beneficial method for identifying NTM, M. tuberculosis (MTB), and Nocardia isolates without sequencing. [ABSTRACT FROM AUTHOR]

Introduction: Mycetoma is a chronic granulomatous inflammatory disease of the subcutaneous tissue, which affects deep structures and bone. Most cases of actinomycetoma are caused by members of the genus Nocardia. Case presentation: Here we report the case of a 43-year-old male who presented a disseminated mycetoma on the forearm, chest and neck, characterized by enlarged and erythematous lesions through which seropurulent material drains, and numerous atrophic scars. Molecular identification was performed by 16S gene amplification and sequencing. Nocardia mexicana was identified with 100% identity. Trimethoprimsulfamethoxazole, diaminodiphenyl sulfone and amikacin was a successful treatment after 6 months. Conclusions: Nocardia mexicana is a rare organism that causes mycetoma. We report a case of extensive mycetoma on the forearm with spread to the neck and thorax associated with manipulation of the mouth of a calf. [ABSTRACT FROM AUTHOR]

Background Nocardiosis, a bacterial opportunistic infection caused by Nocardia spp, has recently been reported in patients with anti–granulocyte-macrophage colony-stimulating factor (GM-CSF) autoantibodies, but insufficient data are available about disease presentation, outcomes, and occurrence of autoimmune pulmonary alveolar proteinosis (aPAP) in this population. Methods We performed a prospective, multicenter, nationwide study in France and included patients with a Nocardia infection who had anti-GM-CSF autoantibodies. We describe their clinical, microbiological, and radiological characteristics, and their outcome at 1 year of follow-up. Results Twenty patients (18 [90%] male) were included, with a median age of 69 (interquartile range, 44–75) years. The organs most frequently involved were the brain (14/20 [70%]) and the lung (12/20 [60%]). Half of the infections were disseminated (10/20 [50%]). Nocardia identification was predominantly made in abscess fluid (17/20 [85%]), among which 10 (59%) were brain abscesses. The 1-year all-cause mortality was 5% (1/20), and only 1 case of aPAP (1/20 [5%]) occurred during the follow-up period. Conclusions Nocardiosis with anti-GM-CSF autoantibodies is associated with a low mortality rate despite a high incidence of brain involvement. Although the occurrence of aPAP was infrequent during the 1-year follow-up period, long-term clinical data are needed to fully understand the potential relationship between nocardiosis, anti-GM-CSF autoantibodies, and aPAP. [ABSTRACT FROM AUTHOR]

Introduction: Kidney transplant recipients are at increased risk of opportunistic infections, including Nocardia. The incidence of nocardiosis in kidney transplant recipients is 0.4-1.3%. The data regarding its epidemiology and outcomes is limited. Methods: This was a 10-year retrospective observational study from January 2012 to December 2021 at a tertiary care center in northern India, in which all kidney transplant recipients with Nocardia infection were included and followed. Results: 12 (1.1%) patients had a Nocardia infection among the 1108 kidney transplant recipients. All were living donor kidney transplant recipients, and the mean age at diagnosis was 48.67 ± 12.60 years. Nocardia infection occurred at a median of 26 months (range 4-235) post-transplantation, with 4 (33.1%) of the cases occurring within a year of transplant. Breakthrough infection occurred in 7 (58.3%) patients on cotrimoxazole prophylaxis. 41.7% (n = 5) cases had an episode of rejection in the preceding year of Nocardia diagnosis. Concurrent cytomegalovirus (CMV) infection was present in one (8.3%) case. The lung was tile most frequently involved organ. Microscopy was positive in all the cases; while culture was positive in 10 cases, and antimicrobial susceptibility testing (AST) were performed for these isolates. The majority (60%) of isolates were resistant to cotrimoxazole. All tested isolates remained susceptible to Amikacin, Imipenem, and Linezolid. No patients experienced Nocardia recurrence after completion of antibiotic therapy. The mortality at 12 months was 66.7% (n = 4), and only one death was Nocardta-related. Conclusion: Nocardia may cause a late-manifesting infection beyond the traditional window. The cotrimoxazole prophylaxis may not be sufficient for Nocardia prevention. [ABSTRACT FROM AUTHOR]

Nocardia is a gram-positive bacillus with the microscopic appearance of branching hyphae and is mainly distributed in the soil. Nocardiosis more frequently occurs in immunosuppressed patients. Since nocardiosis has a high mortality rate, immediate diagnosis and treatment are needed. We report the first case of pulmonary nocardiosis caused by Nocardia pseudobrasiliensis after liver transplantation. A 58-year-old woman underwent living-donor transplantation for primary biliary cholangitis. Seven months after transplantation, she came to our hospital complaining of fever and anorexia. Computed tomography of the lungs showed a 45 mm large nodule affecting the upper lobe of the left lung. We started administering empiric antibiotics and tapering immunosuppression, but the patient's condition gradually worsened, and lung lesions increased. On the fifth day after hospitalization, bacteria developed from sputum cultures were identified as N. pseudobrasiliensis by matrix-assisted laser desorption ionization time of flight mass spectrometry. We started treatment with trimethoprim-sulfamethoxazole. The patient's clinical symptoms and laboratory data improved quickly. After one month of hospitalization, this patient was discharged. Then, the lung lesion almost vanished. Ten years after her transplant, the patient is alive with a well-functioning graft. [ABSTRACT FROM AUTHOR]

A 3‐year‐old Holstein cow was examined in an intensive system due to unilateral swelling in the mandible. A right mandibular mass was associated with painful mastication and Ptyalism. In palpation, the mass was raised, ulcerated, attached to the mandible bone and firm, approximately 17 × 12 × 10 cm3 in size. The lesion was sampled, and after routine bacteriology and histopathology procedures, the occurrence of lumpy jaw caused by Nocardia farcinica was confirmed. The bacterium was analysed using genome sequencing and new strain called Najm 114. Due to the risk of zoonosis of the isolated agent, the cow was euthanized. This is the first report of lumpy jaw caused by N. farcinica in a cow. This study showed that N. farcinica should be considered a possible etiological agent for lumpy jaw in cattle. [ABSTRACT FROM AUTHOR]

Background Nocardia tends to cause infection in immunocompromised patients or those with chronic pulmonary disease. Nocardia is known to recur, prompting the practice of secondary prophylaxis in patients perceived at high risk. However, few data exist regarding the epidemiology of recurrent nocardiosis or the effectiveness of secondary prophylaxis. Methods We performed a multicenter, retrospective cohort study of adults diagnosed with nocardiosis from November 2011 to April 2022, including patients who completed primary treatment and had at least 30 days of posttreatment follow-up. Propensity score matching was used to analyze the effect of secondary prophylaxis on Nocardia recurrence. Results Fifteen of 303 (5.0%) patients developed recurrent nocardiosis after primary treatment. Most recurrences were diagnosed either within 60 days (N = 6/15, 40.0%) or between 2 to 3 years (N = 4/15, 26.7%). Patients with primary disseminated infection tended to recur within 1 year, whereas later recurrences were often nondisseminated pulmonary infection. Seventy-eight (25.7%) patients were prescribed secondary prophylaxis, mostly trimethoprim-sulfamethoxazole (N = 67/78). After propensity-matching, secondary prophylaxis was not associated with reduced risk of recurrence (hazard ratio, 0.96; 95% confidence interval,.24–3.83), including in multiple subgroups. Eight (53.3%) patients with recurrent nocardiosis required hospitalization and no patients died from recurrent infection. Conclusions Recurrent nocardiosis tends to occur either within months because of the same Nocardia species or after several years with a new species. Although we did not find evidence for the effectiveness of secondary prophylaxis, the confidence intervals were wide. However, outcomes of recurrent nocardiosis are generally favorable and may not justify long-term antibiotic prophylaxis for this indication alone. [ABSTRACT FROM AUTHOR]

Nocardia farcinica is rarely isolated from clinical specimens, and it is a more virulent strain than other types of Nocardia. In this report, we evaluated a rare case of pleural empyema and pneumonia caused by Nocardia farcinica in a patient who had risk factors such as long-term use of corticosteroids, chronic respiratory disease, and a brain tumor. The distinction of N. farcinica from other Nocardia species is important because N. farcinica is more virulent and highly resistant, especially to broad-spectrum cephalosporins, which can make treatment difficult. In conclusion, in the presence of nonspecific physical examination and radiographic findings in patients using immunosuppressives and having comorbid diseases, atypical causative agents such as Nocardia infection should be considered in the differential diagnosis. [ABSTRACT FROM AUTHOR]

Background: 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. Aims: 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. Methods: 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. Results: 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. Conclusions: 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. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a progressive neurodegenerative disorder with an unknown cause. Recent research has highlighted the importance of the gut in neuronal and immune maturation through the exchange of nutrients and cellular signals. This has led to the "gut-first PD" hypothesis, which aims to explain many of the sporadic cases and their prodromal intestinal symptoms, such as constipation and intestinal α-synuclein (aSyn) aggregation. The link between mitochondrial dysfunction and aSyn deposition is central to PD pathophysiology, since they can also trigger pro-inflammatory signals associated with aSyn deposition, potentially contributing to the onset of PD. As mitochondria are derived from ancestral alpha-proteobacteria, other bacteria may specifically target this organelle. We sought to use Nocardia cyriacigeorgica, a bacterium previously associated with parkinsonism, and dextran sulfate sodium (DSS) as pro-inflammatory modulators to gain further insight into the onset of PD. This study indicates that aSyn aggregation plus mitochondrial dysfunction without intestinal barrier leakage are not sufficient to trigger gut-first PD. [ABSTRACT FROM AUTHOR]

Actinobacteria are one of the predominant groups that successfully colonize and survive in various aquatic, terrestrial and rhizhospheric ecosystems. Among actinobacteria, Nocardia is one of the most important agricultural and industrial bacteria. Screening and isolation of Nocardia related bacteria from extreme habitats such as endolithic environments are beneficial for practical applications in agricultural and environmental biotechnology. In this work, bioinformatics analysis revealed that a novel strain Nocardia mangyaensis NH1 has the capacity to produce structurally varied bioactive compounds, which encoded by non-ribosomal peptide synthases (NRPS), polyketide synthase (PKS), and post-translationally modified peptides (RiPPs). Among NRPS, five gene clusters have a sequence homology with clusters encoding for siderophore synthesis. We also show that N. mangyaensis NH1 accumulates both catechol- and hydroxamate-type siderophores simultaneously under iron-deficient conditions. Untargeted LC–MS/MS analysis revealed a variety of metabolites, including siderophores, lipopeptides, cyclic peptides, and indole-3-acetic acid (IAA) in the culture medium of N. mangyaensis NH1 grown under iron deficiency. We demonstrate that four CAS (chrome azurol S)-positive fractions display variable affinity to metals, with a high Fe3+ chelating capability. Additionally, three of these fractions exhibit antioxidant activity. A combination of iron scavenging metabolites produced by N. mangyaensis NH1 showed antifungal activity against several plant pathogenic fungi. We have shown that the pure culture of N. mangyaensis NH1 and its metabolites have no adverse impact on Arabidopsis seedlings. The ability of N. mangyaensis NH1 to produce siderophores with antifungal, metal-chelating, and antioxidant properties, when supplemented with phytohormones, has the potential to improve the release of macro- and micronutrients, increase soil fertility, promote plant growth and development, and enable the production of biofertilizers across diverse soil systems. [ABSTRACT FROM AUTHOR]

Nocardia seriolae is the primary aetiological agent of nocardiosis in fish, which causes mass mortality in freshwater and marine fish. β‐ketoacyl‐ACP synthase (KAS) is one of the essential enzymes in the synthesis of mycolic acids (MASs) in Mycobacterium spp. and has been chosen as the target for therapeutic intervention in mycobacterial diseases. In the present study, a kasB homologue gene (kasB) was identified in the genome of N. seriolae, and the gene‐deficient mutant (ΔkasB) was generated based on a clinical isolate, XSYC‐Ns. Compared to the wild‐type (WT) strain, the ΔkasB showed a measurably growth defect in vitro but retained the acid‐fastness in acid‐fast staining. Observation of the cell ultrastructure showed some alterations in the cell wall of the ΔkasB strain. Compared to its original strain, the cell wall lipid layer seemed sparser, and a wider electron‐transparent zone was observed in the cell wall of ΔkasB strain. Moreover, the ΔkasB strain showed impaired ability of cell invasion as well as intracellular survival in the cell line originating from the head‐kidney of the large yellow croaker (LYC‐hK), compared to its original strain. In addition, the deficiency of ΔkasB significantly attenuated the virulence of N. seriolae in largemouth bass. The present study suggested that the ΔkasB gene might be involved in the synthesis of extracellular cell‐wall lipids in N. seriolae and play a crucial role in its pathogenicity. [ABSTRACT FROM AUTHOR]

This article discusses a case study of a 64-year-old female kidney transplant recipient who developed a lung mass. The patient had received immunosuppressive medications and prophylactic antibiotics following the transplant. After presenting with weight loss, fever, and cough, the patient was diagnosed with Nocardia nova infection. Treatment with antibiotics led to significant improvement in the patient's condition. The article emphasizes the importance of considering Nocardia infection in immunocompromised patients and highlights the role of CT imaging in diagnosing and managing the condition. [Extracted from the article]

The article describes the case of a six-year-old girl with schizencephaly, shunted hydrocephalus, epilepsy, global development delay, diabetes insipidus, and spastic quadriplegic cerebral palsy. Topics discussed include findings on her medical examination, major categories of the differential diagnosis for a child with acquired chest wall mass, and final diagnosis of thoraco-abdominal actinomycosis with chest wall invasion.

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. [ABSTRACT FROM AUTHOR]

Nocardiosis is a rare infection of the lung, brain and skin and can be a localized or disseminated infection. Here, we report a case of a 56-year-old male patient who presented with a right testicular torsion for which right orchiectomy was done in the hospital. In the post-operative period, patient developed increased respiratory insufficiency and was intubated. Chest X-ray revealed bilateral fluffy opacities most likely due to infective etiology. Endotracheal tube aspirate sample was sent for Gram staining and culture, organism present showed characteristics like Nocardia. MALDI-TOF identified organism as Nocardia otitidiscaviarum. The patient was treated with cotrimoxazole and ceftriaxone. His clinical condition improved. We report this case because Nocardia otitidiscaviarum is a rare cause of pulmonary nocardiosis and although there is high mortality reported in nocardiosis, early diagnosis because of the availability of advanced diagnostic technology and prompt treatment can help save the patient. [ABSTRACT FROM AUTHOR]

Nocardia are Gram‐positive bacteria from the Actinobacteria phylum. Some Nocardia species can infect humans and are usually considered to be opportunist pathogens, as they often infect immunocompromised patients. Although their clinical incidence is low, many Nocardia species are now considered to be emerging pathogens. Primary sites of infection by Nocardia are the skin or the lungs, but dissemination to other body parts is very frequent. These disseminated infections are very difficult to treat and thus are tackled with multiple classes of antibiotics, in addition to the traditional treatment targeting the folate pathway. β‐Lactams are often included in the regimen, but many Nocardia species present moderate or strong resistance to some members of this drug class. Genomic, microbiological and biochemical studies have reported the presence of class A β‐lactamases (ABLs) in a handful of Nocardia species, but no structural investigation of Nocardia β‐lactamases has yet been performed. In this study, the expression, purification and preliminary biochemical characterization of an ABL from an N. cyriacigeorgica (NCY‐1) clinical strain are reported. The crystallization and the very high resolution crystal structure of NCY‐1 are also described. The sequence and structural analysis of the protein demonstrate that NCY‐1 belongs to the class A1 β‐lactamases and show its very high conservation with ABLs from other human‐pathogenic Nocardia. In addition, the presence of one molecule of citrate tightly bound in the catalytic site of the enzyme is described. This structure may provide a solid basis for future drug development to specifically target Nocardia spp. β‐lactamases. [ABSTRACT FROM AUTHOR]

Introduction. The strain Nocardia vaccinii IMV B-7405, which produces phytohormones and surfactants, is a promising agent for the development of integrated technologies to obtain complex preparation to be used in crop production. Materials and methods. Cultivation of bacteria was carried out in a liquid medium with 2% refined or waste oil and 100-300 mg/l of tryptophan (the precursor of the phytohormone auxin biosynthesis) was added to the medium. The concentration of auxins was determined by the method of high-performance liquid chromatography, surfactants - by weight method. Antimicrobial activity of surfactant was analyzed by the indicator of minimum inhibitory concentration (MIC). Greenhouse experiments were carried out using tomato plants; the number of fruits and their weight were analyzed. Determination of the protective effect of surfactants against bacterial diseases of tomatoes was carried out by the method of separated leaves. Results and discussion. It was established that in the presence of tryptophan in the culture medium of N. vaccinii IMV B-7405 the concentration of auxins was one to two orders of magnitude higher than without the biosynthesis precursor. The increase in auxins synthesis correlated with tryptophan transaminase activity - the key enzyme of auxins biosynthesis. Surfactants synthesized in the presence of tryptophan were characterized by higher antimicrobial activity against phytopathogenic bacteria: MICs were 2-4 times lower compared to those established for preparations formed without a precursor. Treatment of tomato leaves with solutions of surfactants synthesized by N. vaccinii IMV B-7405 in the presence of tryptophan contributed to the protection of leaves from phytopathogens damage. The exometabolites of N. vaccinii IMV B-7405 increased the productivity of tomatoes: the total weight increased by 82-91%, and the average fruit weight by 12-18%. Conclusions. The complex preparation based on the exometabolites (the surfactants and phytohormones) of N. vaccinii IMV B-7405 can be used to control the number of phytopathogens and increased the productivity of tomatoes. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To study the in vitro effect of lysozyme on six strains of Nocardia and to determine whether there is a growth inhibiting effect. MATERIALS AND METHODS: A prospective study was carried out from March to December 2022 in the Immunobiology laboratory of the Metropolitan Autonomous University, Xochimilco campus, Mexico City, in which six strains of Nocardia were grown (5 clinical isolates provided by the Manuel Gea González General Hospital and the reference strain CETC 3032) in BHI broth; they were adjusted to tube 1 of the McFarland nephelometer, and were placed in the presence of the enzyme lysozyme of human neutrophils at different concentrations and times in acetate buffer to later perform the count of microorganisms. RESULTS: Lysozyme showed a growth inhibiting effect at concentrations of 500 and 1000 µg/mL in the Nocardia brasiliensis CETC 3032 strain at 48 hours. N. brasiliensis (clinical isolate 1) and N. farcinica and N. asteroides strains (clinical isolates 3 and 4) showed inhibition of bacterial growth at all three enzyme concentrations tested at 24 hours. CONCLUSIONS: The enzyme lysozyme showed an inhibitory effect on bacterial growth on all strains of Nocardia studied. [ABSTRACT FROM AUTHOR]

We report a rare case of pulmonary nocardiosis with endobronchial involvement caused by Nocardia araoensis. A 79-year-old man with a history of asthma and a previous right upper lobectomy for lung cancer and organizing pneumonia presented with cough and dyspnea. He presented with right bronchial stenosis associated with various mucosal lesions, including ulcerative and exophytic lesions. N araoensis was detected in sputum samples collected via bronchoscopy. The mucosal lesions improved after a 2-week course of meropenem. After a further 6 months of oral sulfamethoxazole-trimethoprim treatment, the mucosal lesions completely disappeared. Based on bronchoscopic and pathophysiologic findings, the patient was diagnosed with pulmonary nocardiosis with endobronchial involvement. Nocardiosis should be considered in the differential diagnosis of endobronchial mucosal lesions. [ABSTRACT FROM AUTHOR]

Background: Nocardiosis is a rare, but potentially life-threatening condition. It is difficult to diagnose, and bacterial culture identification can be time consuming. We investigated the characteristics of nocardiosis and the suitability of the treatment approach in Korea. Materials and Methods: This retrospective study was conducted at 5 medical institutions between 2011 and 2021. We reviewed the medical records of patients with microbiologically confirmed nocardiosis. Appropriate antibiotic selection was defined as follows: (1) selecting antibiotics according to the species, (2) if the species of Nocardia was unknown, trimethoprim-sulfamethoxazole-based therapy or linezolid-based therapy was administered, and (3) selection of antibiotics using the antibiotic susceptibility test. The appropriate treatment periods for antibiotics were defined as treatment maintained from 3 to 12 months, depending on involvement of the organs. Descriptive analysis and Fisher exact test were used. Statistical significance was set at P-values of <0.05. Results: Thirty patients were enrolled. Of these patients, 18 (60.0%) were male. The median age was 70.5 years. Among the diagnosed patients, 12 (40.0%) had an immunocompromised status. Eight (30.0%) patients received optimal treatment for the appropriate treatment period. Appropriate dosing duration was observed in 3 of the 12 (25.0%) immunocompromised patients. There was no significant difference between the presence or absence of immunosuppression and the adequacy of treatment for nocardiosis (P = 1.000). Skin and soft tissue (14 patients) were most frequently involved in this study. Nocardia species (spp.) were isolated from culture at a median of 6.0 days. There were 7 cases with N. farcinica (23.3%). Conclusion: We found that 60.0% of the patients with nocardiosis did not have an immunocompromised status. Further, 26.7% of the total patients received adequate treatment for nocardiosis. The reasons for suboptimal management of nocardiosis in Korea are presumed to be diagnostic difficulties, lack of awareness about nocardiosis, and difficulties in selecting antibiotics for Nocardia spp. among clinicians. The lack of antibiotic susceptibility tests for Nocardia spp. could be the source of these problems. Nocardiosis should be suspected in cases of recurrent infections with skin and soft tissue, musculoskeletal, or respiratory system involvement with or without an immunocompromised status. Clinical microbiological support is required for the diagnosis and selection of antibiotics in Korea. High clinical index of suspicion and clinical microbiological support are required for the accurate diagnosis of nocardiosis in Korea. [ABSTRACT FROM AUTHOR]

Targeted therapy with tumour‐associated macrophages (TAMs) has emerged as a new paradigm for immunotherapy of cervical cancer. Nocardia rubra cell wall skeleton (Nr‐CWS) for external use is an immunotherapeutic agent. In this study, we aimed to explore the effects of Nr‐CWS on TAMs and the potential mechanisms. Cervical tissue samples were collected before and after Nr‐CWS treatment from patients with high‐risk HPV infection and cervical intraepithelial neoplasia (CIN). The effect of Nr‐CWS on macrophages in vivo was examined by immunohistochemistry and double‐labeling immunofluorescence histochemistry. In vitro experiments were performed using a TAM model established by THP‐1 cells under Nr‐CWS treatment. We found that Nr‐CWS treatment significantly reduced the numbers of total macrophages and M2 macrophages, increased the proportion of M1 macrophages and decreased the proportion of M2 macrophages in cervical tissues. After Nr‐CWS treatment in vitro, the expression levels of the M1 macrophage markers were increased, while the expression levels of the M2 macrophage markers were decreased. Nr‐CWS treatment also activated STAT1 pathways but inhibited STAT6 pathways. These results indicated that Nr‐CWS may improve local immune response and reverse immunosuppression by regulating the M2 to M1 polarization of TAMs via STAT1/STAT6 pathways. [ABSTRACT FROM AUTHOR]

Nocardia keratitis is mostly seen in patients with alcoholism, malnutrition, or HIV. Its chronic waxing-and-waning course makes it difficult to diagnose. A 53-year-old male presented with pain and redness in his right eye for the past 3 weeks. The cornea had paracentral ulcer with stromal infiltrates and multiple satellite lesions giving wreath-like appearance suggestive of Nocardia. After corneal scraping, fortified amikacin, moxifloxacin, and cycloplegics were started. Gram stain revealed filamentous, branching Gram-positive bacteria and acid-fast on Ziehl-Neelsen stain confirming our clinical diagnosis. Ulcer completely resolved over 6 weeks. Thus, a high index of clinical suspicion which was further backed by microbiological confirmation aided in expedient management ensuring a successful outcome. [ABSTRACT FROM AUTHOR]