Actinomycoses and Nocardia pulmonary infections

Exhaled volatile organic compounds associated with chronic obstructive pulmonary disease exacerbations-a systematic review and validation

Chronic obstructive pulmonary disease (COPD) exacerbations significantly contribute to disease progression, hospitalizations, and decreased quality of life. Early detection of exacerbations through non-invasive methods, such as exhaled volatile organic compounds (VOCs), could enable timely interventions. This study aimed to identify and validate candidate VOC biomarkers that are associated with exacerbations and stable phases of COPD, and could contribute to the development of a breath-based monitoring device. A systematic review was conducted to identify VOCs associated with COPD and exacerbations. VOCs were selected as candidate biomarkers if they were reported in at least two studies by different research groups. These VOCs were then validated using longitudinal exhaled breath data from the TEXACOLD study, where exhaled breath samples were collected at baseline, during exacerbation, and at follow-up in 14 COPD patients. Sparse partial least squares-discriminant analysis was applied to differentiate between samples collected during exacerbation and those at stable phases. Diagnostic accuracy was assessed using receiver operating characteristic (ROC) curves. The systematic review identified nine candidate VOCs. Three were excluded from validation because their dataset overlapped with one used in one of the included review studies. Validation confirmed the discriminatory power of a composite model of these six VOCs, achieving an area under the ROC curve of 0.98, a diagnostic accuracy of 94.3% and a sensitivity of 0.97 and a specificity of 0.93. This study demonstrates that exhaled VOCs can differentiate between exacerbations and stable phases in COPD patients. The validated biomarkers hold promise for future clinical applications, particularly in the development of a non-invasive, breath-based monitoring device for early detection and management of COPD exacerbations, potentially reducing hospitalizations and improving patient outcomes.

Exposing the Masquerade of Nocardia otitidiscaviarum Pneumonia: A Case Report

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.

Nocardia in an Immunocompetent Patient Simulating Pulmonary Carcinoma: A Case Report and Literature Review

Nocardiosis is an opportunistic infectious pathology of low incidence that usually affects the lungs, skin, and brain. It has been implicated in causing serious and potentially fatal infections without treatment. It affects immunocompetent and immunocompromised patients. In immunocompetent patients, it is presented with local conditions, and in immunocompromised patients, it is seen in disseminated forms. We present the case of a 61-year-old male immunocompetent patient with a high suspicion of pulmonary carcinoma, in whom pathology showed infection by Nocardia spp.

Bacteremia caused by Nocardia farcinica: a case report and literature review

BACKGROUND

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.

CASE PRESENTATION

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.

CONCLUSION

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.

Rapid detection of pulmonary nocardiosis by metagenomic next generation sequencing

We retrospectively analyzed 3 cases of pulmonary nocardiosis. Patients were identified by metagenomic next generation sequencing (mNGS) in the First Affiliated Hospital of Soochow University, from January 2019 to April 2022. All patients had underlying diseases, and were in immunocompromised state, with membranous nephropathy, acute lymphoblastic leukemia (ALL), and systemic lupus erythematosus (SLE), respectively. Symptoms common to all cases included fever, cough and expectoration. Chest computed tomography (CT) presented patchy shadows or nodules, with or without cavitation lesions, or pleural effusion. mNGS detected Nocardia spp. via bronchoalveolar lavage fluid (BALF) or blood samples from patients. All the patients were discharged with recovery after using the trimethoprim-sulfamethoxazole (TMP-SMX) and remained without evidence of disease during regular follow-ups. mNGS may be a tool for rapid and accurate detection and identification of pulmonary nocardiosis, but interpreting the mNGS results should be more cautious because the mNGS assay can also detect colonization.

Ulceration by Nocardia Otitidiscaviarum: A case study

Nocardiosis is an acute, subacute or chronic infectious disease that occurs in cutaneous, pulmonary and disseminated forms. We present a case of Nocardiosis in a post-COVID-19 patient with cutaneous ulceration due to Nocardia otitidiscaviarum, managed with cotrimoxazole and linezolid. Early diagnosis and management proved crucial in preventing dissemination of the organism and improving the patient's outcome.

Clinical and radiological characteristics of pulmonary actinomycosis mimicking lung malignancy

INTRODUCTION

Pulmonary actinomycosis, clinically and radiologically, mimics abscess, tuberculosis, and lung malignancy, resulting in misdiagnosis or delay in diagnosis. In this study, we analyzed the clinicoradiological features of pulmonary actinomycosis, the presence of any differences between clinical prediagnosis and radiological diagnosis, and whether imaging modalities help distinguish pulmonary actinomycosis from lung cancer.

METHODS

A total of 22 patients who had a histopathological diagnosis of actinomycosis in a tertiary health center participated in this study. Of these, 14 had positron-emission tomography/computed tomography.

RESULTS

In all, 81.8% of the patients were males. The diagnostic procedures employed for the diagnosis of actinomycosis were surgery in 54.5% of patients, fiberoptic bronchoscopy in 36.4% of patients, and rigid bronchoscopy in 9.1% of patients. Radiological and clinical prediagnosis showed malignancy in 31.8 and 40.9% of patients, respectively. The mean of the maximum standardized uptake value was 6.33±3.6 on positron-emission tomography/computed tomography. Kappa compliance analysis revealed that clinical and radiological diagnoses were significantly compatible with each other and that radiological pre-diagnoses were not superior to clinical diagnoses (κ=0.701 and p<0.001).

CONCLUSION

Pulmonary actinomycosis shows high metabolic uptake in positron-emission tomography/computed tomography, and this may mislead clinicians for a diagnosis of malignancy. Our results suggest that positron-emission tomography/computed tomography does not help distinguish pulmonary actinomycosis from lung malignancy and does not provide a clear diagnostic benefit to the clinician, so pathological diagnosis is necessary.

Pulmonary alveolar proteinosis complicated with nocardiosis: A case report and review of the literature

BACKGROUND

Pulmonary alveolar proteinosis (PAP) is a pulmonary syndrome wherein large volumes of phospholipid and protein-rich surfactants accumulate within the alveoli. PAP forms include primary (auto-immune PAP), secondary, and congenital. Nocardiosis is a form of suppurative disease induced upon infection with bacteria of the Nocardia genus. Clinically, cases of PAP complicated with Nocardia infections are rare, regardless of form. Unfortunately, as such, they are easily overlooked or misdiagnosed. We describe, here, the case of a patient suffering from simultaneous primary PAP and nocardiosis.

CASE SUMMARY

A 45-year-old Chinese man, without history of relevant disease, was admitted to our hospital on August 8, 2018 to address complaints of activity-related respiratory exertion and cough lasting over 6 mo. Lung computed tomography (CT) revealed diffuse bilateral lung infiltration with local consolidation in the middle right lung lobe. Subsequent transbronchial lung biopsy and CT-guided lung biopsy led to a diagnosis of primary PAP (granulocyte-macrophage colony-stimulating factor antibody-positive) complicated with nocardiosis (periodic acid-Schiff-positive). After a 6 mo course of anti-infective treatment (sul-famethoxazole), the lesion was completely absorbed, such that only fibrous foci remained, and the patient exhibited significant symptom improvement. Follow-up also showed improvement in pulmonary function and the CT imaging findings of PAP. No whole-lung lavage has been conducted to date. This case highlights that active anti-nocardia treatment may effectively improve the symptoms and alleviate PAP in patients with PAP and nocardia, possibly reducing the need for whole-lung lavage.

CONCLUSION

When evaluating patients presenting with PAP and pulmonary infections, the potential for nocardiosis should be considered.

Isolated Nocardiosis, an Unrecognized Primary Immunodeficiency?

Nocardiosis is an infectious disease caused by the gram-positive bacterium Nocardia spp. Although it is commonly accepted that exposure to Nocardia is almost universal, only a small fraction of exposed individuals develop the disease, while the vast majority remain healthy. Nocardiosis has been described as an "opportunistic" disease of immunocompromised patients, suggesting that exposure to the pathogen is necessary, but a host predisposition is also required. Interestingly, increasing numbers of nocardiosis cases in individuals without any detected risk factors, i.e., without overt immunodeficiency, are being reported. Furthermore, a growing body of evidence have shown that selective susceptibility to a specific pathogen can be caused by a primary immunodeficiency (PID). This raises the question of whether an undiagnosed PID may cause nocardiosis affecting otherwise healthy individuals. This review summarizes the specific clinical and microbiological characteristics of patients with isolated nocardiosis published during the past 30 years. Furthermore, it gives an overview of the known human immune mechanisms to fend off Nocardia spp. obtained from the study of PIDs and patients under immunomodulatory therapies.

Genomic Virulence Features of Two Novel Species Nocardia barduliensis sp. nov. and Nocardia gipuzkoensis sp. nov., Isolated from Patients with Chronic Pulmonary Diseases

Strains 335427^T and 234509^T, isolated from two 76-year-old patients with chronic pulmonary diseases, were the subject of polyphasic taxonomic studies and comparative genomic analyses for virulence factors. The 16 rRNA gene sequence similarity between strains 335427^T and 234509^T and their closest phylogenetic neighbors Nocardia asiatica NBRC 100129^T and Nocardia abscessus NBRC 100374^T were 99.5% and 100%, respectively. Digital DNA-DNA hybridization values between the aforementioned studied strains were well below the 70% threshold for assigning prokaryotic strains to a novel species. Strains 335427^T and 234509^T have genome sizes of 8.49 Mpb and 8.07 Mpb, respectively, with G + C content of 68.5%. Isolate 335427^T has C_16:0, C_18:1 ω₉c, C_18:0 and C_18:0 10 methyl as major fatty acids (>15%) and mycolic acids formed of 52-54 carbon atoms. However, only C_18:1 ω₉c was detected for isolate 234509^T, which had mycolic acids with 44-56 carbon. Based on phenotypic and genetic data, strains 335427^T (DSM 109819^T = CECT 9924^T) and 234509^T (DSM 111366^T = CECT 30129^T) merit recognition as novel species, which are named Nocardia barduliensis sp. nov. and Nocardia gipuzkoensis sp. nov., respectively. All the strains studied had homologous VF-associated genes to those described in M. tuberculosis, including experimentally verified virulence genes in humans related to tuberculosis. The narGHIJ (nitrate reduction pathway) and gvpAFGOJLMK (gas vesicles) genetic maps of strains 335427^T, 234509^T, NBRC 100129^T and NBRC 100374^T showed the same syntenic block and raise the question of whether their functions are interlinked during the infection of the human host. However, further research is required to decipher the role of the gas vesicle in the pathogenicity mechanism of Nocardia spp.

Efficient differentiation of Nocardia farcinica, Nocardia cyriacigeorgica and Nocardia beijingensis by high-resolution melting analysis using a novel locus

Accurate identification of Nocardia species remains a challenge due to the complexities of taxonomy and insufficient discriminatory power of traditional techniques. We report the development of a molecular technique that utilizes real-time PCR-based high-resolution melting (HRM) analysis for differentiation of the most common Nocardia species. Based on a novel fusA-tuf intergenic region sequence, Nocardia farcinica, Nocardia cyriacigeorgica and Nocardia beijingensis were clearly distinguished from one another by HRM analysis. The limit of detection of the HRM assay for purified Nocardia spp. DNA was at least 10 fg. No false positives were observed for specificity testing of 20 non-target clinical samples. In comparison to established matrix-assisted laser desorption/ionization-time of flight MS, the HRM assay improved the identification of N. beijingensis. Additionally, all the products of PCR were verified by direct sequencing. In conclusion, the developed molecular assay allows simultaneous detection and differentiation of N. farcinica, N. cyriacigeorgica and N. beijingensis with high sensitivity and specificity.

Infectious Lung Disease

Infectious diseases are one of the main causes of morbidity and mortality worldwide. With new pathogens continuously emerging, known infectious diseases reemerging, increasing microbial resistance to antimicrobial agents, global environmental change, ease of world travel, and an increasing immunosuppressed population, recognition of infectious diseases plays an ever-important role in surgical pathology. This becomes particularly significant in cases where infectious disease is not suspected clinically and the initial diagnostic workup fails to include samples for culture. As such, it is not uncommon that a lung biopsy becomes the only material available in the diagnostic process of an infectious disease. Once the infectious nature of the pathological process is established, careful search for the causative agent is advised. This can often be achieved by examination of the hematoxylin and eosin-stained sections alone as many organisms or their cytopathic effects are visible on routine staining. However, ancillary studies such as histochemical stains, immunohistochemistry, in situ hybridization, or molecular techniques may be needed to identify the organism in tissue sections or for further characterization, such as speciation.

Diagnosis of Infectious Diseases in the Lower Respiratory Tract: A Cytopathologist's Perspective

CONTEXT.—

Respiratory cytology continues to play an important role in the diagnosis of lower respiratory tract infections. Prompt, accurate diagnosis of causative organisms is of paramount importance, particularly in immunosuppressed patients. In addition, a rapidly expanding arsenal of ancillary testing is now available, aiding tremendously in organism identification.

OBJECTIVE.—

To provide an updated review on the cytomorphologic features of common organisms in lower respiratory tract infection. Relevant ancillary tests, differential diagnoses, and potential pitfalls of organism identification will also be discussed.

DATA SOURCES.—

Data for this review were gathered from PubMed searches of infectious diseases of the lower respiratory tract, especially related to the diagnoses.

CONCLUSIONS.—

The lower respiratory tract is subject to infection by a wide variety of infectious agents. Pathologists should be familiar with common organisms, including their general clinical characteristics, cytomorphologic features, differential diagnoses, and ancillary methods of detection. Above all, correlation with microbiologic and clinical information is necessary to make a confident diagnosis of infection.

Pulmonary actinomycosis diagnosed by transbronchoscopic lung biopsy: A case report and literature review

Pulmonary actinomycosis is a chronic, suppurative, granulomatous disease caused by Actinomyces israelii, an obligate anaerobe. The clinical manifestations and imaging characteristics of pulmonary actinomycosis lack specificity and can lead to confusion with tuberculosis and lung cancer. The present study reported a case of pulmonary actinomycosis diagnosed by transbronchoscopic lung biopsy and reviewed the literature on the disease. The clinical characteristics, signs, laboratory findings as well as progression, diagnosis and treatment in the case of pulmonary actinomycosis were analyzed. The patient was diagnosed by transbronchoscopic lung biopsy. After two weeks of antibiotic therapy, the cough was significantly improved and the patient's temperature returned to normal. Moreover, the lesion in the left lower lung was significantly smaller. Pulmonary actinomycosis is usually confused for tuberculosis and lung cancer. The present findings indicated that transbronchoscopic lung biopsy is a useful tool for diagnosing the disease. To conclude, doctors should have a clear enough understanding of the disease to prescribe empirical antibiotics and avoid unnecessary surgery.

Disseminated nocardiosis caused by Nocardia elegans: a case report and review of the literature

BACKGROUND

Disseminated nocardiosis is a rare disease mostly occurring in immunocompromised patients.

METHODS

We report a case of disseminated nocardiosis in a diabetic patient with both pulmonary and cutaneous involvement. Nocardia elegans was isolated and identified using the 16s ribosomal RNA gene sequence data.

RESULTS

Clinical improvement was observed within 3 months after initiation of antimicrobial treatment with oral doxycycline, trimethoprim-sulfamethoxazole and intravenous penicillin, but the patient died 5 months later after arbitrary discontinuation of the treatment.

CONCLUSIONS

This is the first case report of disseminated nocardiosis caused by Nocardia elegans in China.

Lung Infections

A review of pulmonary infections of all types with diagnostic and morphological features.

The cytopathology of Actinomyces, Nocardia, and their mimickers

Nocardia species and Actinomyces species are 2 of the most commonly diagnosed filamentous bacteria in routine cytopathology practice. These genera share many overlapping cytomorphologic features, including their thin, beaded, branching, Gram-positive, GMS-positive filamentous structures that fragment at their peripheries into bacillary- and coccoid-appearing forms. Features that help distinguish between these 2 microorganisms include the width of their filamentous structures, the angles at which they branch, and their ability or lack thereof to retain a modified acid-fast stain. In addition to cytomorphologic overlap, overlap in clinical presentation is frequent with pulmonary and mucocutaneous presentations seen in both. Differentiating between Nocardia and Actinomyces is essential because patients with these infections require different approaches to medical management. Both antibiotic susceptibilities and the need for early surgical intervention as part of the treatment plan vary greatly among these 2 groups. This review focuses on the clinical presentation, cytomorphology and staining characteristics that can be useful in identifying and distinguishing between Nocardia and Actinomyces infections, as well as their mimickers.

Severe pneumonia due to Nocardia otitidiscaviarum identified by mass spectroscopy in a cotton farmer: A case report and literature review

RATIONALE

Nocardia species are aerobic saprophytic bacilli. Among Nocardia species, Nocardia otitidiscaviarum (N otitidiscaviarum) is rarely reported in pulmonary infection.

PATIENT CONCERNS

We reported a case of N otitidiscaviarum pneumonia in a cotton farmer.

DIAGNOSES

N otitidiscaviarum pneumonia was identified by mass spectroscopy.

INTERVENTIONS

Combined treatments (amikacin, imipenem and trimethoprim-sulfamethoxazole) were administered after identification of N otitidiscaviarum.

OUTCOMES

The patient eventually died from severe respiratory insufficiency in the hospital.

LESSONS

Early precise diagnosis and prompt combined therapy are of vital importance in severe Nocardia pulmonary infection.

A Case of Nocardia farcinica Pneumonia and Mediastinitis in an Immunocompetent Patient

Nocardia species are aerobic, gram-positive pathogens found worldwide in soil. Nocardia is considered an opportunistic pathogen, and its infection mostly occurs in immunocompromised patients. We report a case of Nocardia farcinica induced mediastinitis and pneumonia that occurred in a 64-year-old male patient who had no significant medical history except for hypertension. He visited another hospital with a complaint of dyspnea and left chest wall pain. The symptoms arose 7 days ago without any trauma and they worsened. A mediastinal mass was found on computed tomography scan. After being transferred to our hospital for further evaluation, he was diagnosed with mediastinitis and pneumonia. As N. farcinica was found to be the causative organism by 16S rRNA sequencing, proper antibiotic therapy including trimethoprim/sulfamethoxazole was initiated immediately. After this, the patient improved and he was discharged. If an infection has a disseminating course, nocardiosis cannot be excluded even in immunocompetent patients. Once the diagnosis is established, prompt antibiotic therapy should be performed based on the severity.

Lung abscess-etiology, diagnostic and treatment options

Lung abscess is a type of liquefactive necrosis of the lung tissue and formation of cavities (more than 2 cm) containing necrotic debris or fluid caused by microbial infection. It can be caused by aspiration, which may occur during altered consciousness and it usually causes a pus-filled cavity. Moreover, alcoholism is the most common condition predisposing to lung abscesses. Lung abscess is considered primary (60%) when it results from existing lung parenchymal process and is termed secondary when it complicates another process, e.g., vascular emboli or follows rupture of extrapulmonary abscess into lung. There are several imaging techniques which can identify the material inside the thorax such as computerized tomography (CT) scan of the thorax and ultrasound of the thorax. Broad spectrum antibiotic to cover mixed flora is the mainstay of treatment. Pulmonary physiotherapy and postural drainage are also important. Surgical procedures are required in selective patients for drainage or pulmonary resection. In the current review we will present all current information from diagnosis to treatment.

Infections and Chronic Inflammatory Bowel Disease

In the more recent years since the introduction of anti-TNF therapy, the treatment strategy in chronic inflammatory bowel disease has developed more towards an early intensive, often double immunosuppression. While this leads to an improved therapeutic success, this intensified therapy also increases the risk for side effects and especially for infectious complications. The early detection of this complication in the immunocompromised patient is often more difficult due to the potential broad spectrum of infectious agents, the often atypical presentation in conjunction with the immunosuppression as well as often similar symptoms regarding intestinal infectious complications common for a flare of the underlying disease. In the first part, this overview will discuss the broad spectrum of potential infectious complications, using pulmonary infections as an example and presenting an algorithm for detection and therapy. In the second part, common intestinal infectious complications will be discussed from diagnosis to therapy.

Human Nocardia Infections: A Review of Pulmonary Nocardiosis

Human nocardiosis may present as an acute or a chronic infection. Although a saprophyte Nocardia spp are responsible for superficial skin infections, pulmonary infections, and disseminated nocardiosis usually involving patients who are immunosuppressed and debilitated. Infections in immunocompetent individuals are usually chronic and present non-specific symptoms. Invasive and disseminated nocardiosis is common among patients with weakened cellular immune systems. Clinical diagnosis of pulmonary nocardiosis is difficult owing to the similarity of its presentation with other respiratory pathogens that include Actinomycetes members and Mycobacteriumtuberculosis. Laboratory diagnosis of human nocardiosis is plagued by the fact that a culture of Nocardia spp requires prolonged incubation periods for isolation which most laboratories fail to follow. The lack of clinical, laboratory, and epidemiological data on the incidence of nocardiosis in humans undermines its significance as a potential pathogen. This review attempts to reexamine the pathogenic potential of Nocardia in human infections

Pulmonary infiltrate and painful nodular leg lesions in a patient with membranous glomerulonephritis

Nocardia otitidis-cavarium is rarely isolated as an infectious pathogen in the western world. We report on a 71-year-old Caucasian man with membranous glomerulonephritis who presented with several seemingly unrelated clinical symptoms that, after laborious diagnostics, turned out to be caused by disseminated infection with N. otitidis-cavarium. This case highlights the variable clinical presentations that can occur in nocardial infections and underscores the need to search for rare pathogens in patients taking immunosuppressive medication.

Differentiation between Nocardia spp. and Mycobacterium spp.: Critical aspects for bacteriological diagnosis

New methodologies were developed for the identification of Nocardia but the initial diagnosis still requires a fast and accurate method, mainly due to the similarity to Mycobacterium, both clinical and bacteriologically. Growth on Löwenstein-Jensen (LJ) medium, presence of acid-fast bacilli through Ziehl-Neelsen staining, and colony morphology can be confusing aspects between Nocardia and Mycobacterium. This study describes the occurrence of Nocardia spp. in a mycobacterial-reference laboratory, observing the main difficulties in differentiating Nocardia spp. from Mycobacterium spp., and correlating isolates with nocardiosis cases. Laboratory records for the period between 2008 and 2012 were analyzed, and the isolates identified as Nocardia sp. or as non-acid-fast filamentous bacilli were selected. Epidemiological and bacteriological data were analyzed as well. Thirty-three isolates identified as Nocardia sp. and 22 as non-acid-fast bacilli were selected for this study, and represented 0.12% of isolates during the study period. The presumptive identification was based on macroscopic and microscopic morphology, resistance to lysozyme and restriction profiles using the PRA-hsp65 method. Nocardia spp. can grow on media for mycobacteria isolation (LJ and BBL MGIT™) and microscopy and colony morphology are very similar to some mycobacteria species. Seventeen patients (54.8%) were reported and treated for tuberculosis, but presented signs and symptoms of nocardiosis. It was concluded that the occurrence of Nocardia sp. during the study period was 0.12%. Isolates with characteristics of filamentous bacilli, forming aerial hyphae, with colonies that may be pigmented, rough and without the BstEII digestion pattern in PRA-hsp65 method are suggestive of Nocardia spp. For a mycobacterial routine laboratory, a flow for the presumptive identification of Nocardia is essential, allowing the use of more accurate techniques for the correct identification, proper treatment and better quality of life for patients.

Bronchial dentures as a cause of airway actinomycosis

A 65-year-old man was referred to the respiratory clinic with recurrent chest infections on a background of stage 3 chronic obstructive pulmonary disease. On examination, there was wheeze bilaterally more marked on the left lower lobe. Subsequent imaging revealed an obstruction of the left main bronchus that was concerning for malignancy. Initially, on flexible bronchoscopy, a hard mass was found and multiple biopsies were positive for actinomycosis. Subsequent rigid bronchoscopy was undertaken and a set of dentures were removed from the airway.

Thoracopulmonary actinomycosis, a case report of a 42-year-old man with coughing and a bump in his right axilla

The diagnosis of thoracopulmonary actinomycosis is challenging because it is a rare disease, symptoms are aspecific and can mimic a lot of other lung pathologies. Especially the differential diagnosis with pulmonary tuberculosis is difficult because clinical symptoms are often very similar. We present a case of thoracopulmonary abcedating actinomycosis in a young immunocompetent man with no predisposing illness. He was initially treated for pulmonary tuberculosis. He showed good response to IV penicillin, which was later switched to oral amoxicillin when he went home.

Clinical and radiographic characteristics of pulmonary nocardiosis: clues to earlier diagnosis

Background and objectives

Pulmonary nocardiosis (PN) is a rare but life-threatening disease that is caused by Nocardia spp. The aim of this study was to characterize the common risk factors, clinical features, imaging findings, treatment and outcomes of PN, which are useful for an early diagnosis and patient management.

Methods

From January 2009 to June 2013, a retrospective study was performed on all PN cases that were diagnosed at our hospital.

Results

The study included 17 patients who were diagnosed with PN. Of these patients, 4 developed concomitant disseminated disease. A male predominance was observed among the patients with PN (76.47%). The most common risk factors were corticosteroid therapy (64.71%), diabetes mellitus (29.41) and chronic lung disease (23.53%). Cough and fever were the most common symptoms (94% and 71%, respectively). One or more nodules or masses (82.35%) and consolidations (58.82%) were the most frequent radiologic abnormalities, and cavitation mostly occurred within two weeks. The median time to diagnosis was 25 days. Overall, the mortality rate was 18.75% for PN, and death was most frequent among patients who received immunosuppressive drugs. For the patients with central nervous system involvement, the mortality rate was 50%.

Conclusion

PN remains a rare opportunistic infection that mainly affects immunocompromised patients. A high clinical index of suspicion is necessary for an early diagnosis and timely treatment in immunocompromised patients who present with new nodules or masses evolving into cavitation in a short amount of time.

Endobronchial actinomycosis after airway stenting

Actinomycosis is a chronic suppurative infection with filamentous, gram-positive, nonspore forming anaerobic bacteria of the genus Actinomyces. Actinomyces species are commensals of the human oropharynx, gastrointestinal tract, and female genitalia. Involvement of the thorax accounts for 15% to 20% of actinomycosis cases. Thoracic actinomycosis classically presents as an intrapulmonary infection of the alveoli, peribronchial tissue, and/or bronchioles. Endobronchial actinomycosis is a rare condition that has been reported in association with aspiration of a foreign body or broncholithiasis. A critical component in the pathogenesis is disruption of the mucosal barrier, thereby allowing invasion of the microorganisms from aspirated oropharyngeal secretions. Even with a high clinical suspicion, actinomycosis is a diagnostic challenge. The most common symptoms of endobronchial actinomycosis include cough, sputum production, and fever. The disease is often confused with lung cancer, tuberculosis, fungal infections, nocardiosis, and poorly responding pneumonia. The present case highlights the first reported case of endobronchial actinomycosis associated with a covered nitinol endobronchial stent.

Pulmonary actinomycosis during the first decade of 21st century: cases of 94 patients

Background

Pulmonary actinomycosis is a chronic pulmonary infection caused by Actinomyces. Both improving oral hygiene and early application of antibiotics to the case of suspicious pulmonary infections result in changes in incidences and presentations of pulmonary actinomycosis. However, there are little reports dealt with the recent clinical characteristics of pulmonary actinomycosis. This study aimed to review the characteristics of pulmonary actinomycosis occurred during the first decade of 21st century.

Methods

This retrospective study was performed on 94 subjects with pulmonary actinomycosis diagnosed pathologically from January 2000 to December 2010 in 13 hospitals in Korea.

Results

The data of the study showed that pulmonary actinomycosis occurs frequently in middle to old-aged males (mean age; 57.7 years old) and that the most common symptoms are cough, hemoptysis, and sputum production. Various radiologic features such as the consolidation with central low attenuation (74.5%) and no regional predominance were also observed. Most of patients recovered completely with medical and/or surgical treatment, reaching approximately 98% cure rate.

Conclusions

The results demonstrate that pulmonary actinomycosis is one of the cautious pulmonary diseases. More importantly, in cases of persistent hemoptysis or for differential diagnosis from lung malignancy, our data have revealed that surgical resection appears to be a useful intervention and that radiologic diagnosis may not provide decisive information. These findings indicate that it is important for the clinicians to include pulmonary actinomycosis as one of differential diagnoses for refractory pulmonary abnormal lesions to the current usual management.

A 75-year-old female with hemoptysis and recurrent respiratory infections

This paper describes the case of a 75-year-old female who presented with significant hemoptysis over a 7–10 day period. She had a history of a left lower lobectomy 10 years prior for a “lung abscess.” She subsequently had multiple episodes of cough, fevers, and possible pneumonia treated with multiple courses of Amoxicillin and Amoxicillin/Clavulanate. Review of her chest CT upon presentation to the hospital showed a large necrotic lingular infiltrate, which had been progressively increasing in size over at least one year. Bronchoscopy showed a yellowish, soft round body in the superior lingular subsegment. Endobronchial and transbronchial biopsies showed actinomyces species. This is a very interesting case of indolent actinomycosis which we suspect had a very slow progressive course secondary to the multiple courses of antibiotics that the patient was treated with.

The 10 warning signs: a time for a change?

PURPOSE OF REVIEW

It is 20 years since the 10 Warning Signs of primary immunodeficiency (PID) were first published and with over 180 PIDs now identified it is timely to evaluate their effectiveness, given the broadening clinical spectrum of PID.

RECENT FINDINGS

Two recent studies have sought to define the features that best identify patients with PID and compare these with the 10 Warning Signs. They suggest the 10 Warning Signs discriminate poorly between those with and without PID, and that other features identify about one-third of patients with PID in whom none of the 10 Warning Signs was present. Recent literature describes the diverse presenting features that may assist in more accurately identifying those with PID.

SUMMARY

Further development and refinement of early warning signs in light of the growing knowledge of how PIDs manifest clinically may allow relatively simple yet effective guidelines targeted at different groups to better detect PID.

Surgery for other pulmonary fungal infections, Actinomyces, and Nocardia

Surgical participation in the management of fungal infections has changed since the advent of effective antimicrobials. Even so, a surgeon may be called on for a variety of reasons, depending on the specific fungal infection and the evolution of thoracic disease. Specific fungal infections are enumerated. Each organism, its clinical picture, and method of diagnosis are briefly described and the medical and surgical management of thoracic disease are discussed.