Increasing Nocardia Incidence Associated with Bronchiectasis at a Tertiary Care Center

Clinical characteristics and drug resistance of Nocardia in Henan, China, 2017-2023

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pulmonary Nocardiosis With Endobronchial Involvement Caused by Nocardiaaraoensis

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.

Pulmonary nocardiosis following nodular bronchiectatic Mycobacterium avium complex pulmonary disease in an immunocompetent patient

A woman in her 70s with a history of nodular bronchiectatic Mycobacterium avium complex pulmonary disease (MAC-PD) presented with an exacerbated productive cough and worsening findings on chest imaging. Although repeated sputum culture tests were negative for acid-fast bacilli and only revealed normal respiratory flora, a bronchoscopy identified Nocardia sp. Consequently, she was diagnosed with pulmonary nocardiosis and was successfully treated with levofloxacin. It is known that pulmonary nocardiosis can manifest in immunocompetent individuals with bronchiectasis. For cases of refractory nodular bronchiectatic MAC-PD, it is vital to consider bronchoscopy to identify potential co-infections, such as Nocardia.

A 53-Year-Old Woman With Seizure and Cavitary Lung Mass

CASE PRESENTATION

A 53-year-old woman with no significant past medical history came to her local ED after a witnessed generalized tonic-clonic seizure. CT scan imaging of the head revealed a left frontal lobe hypodensity concerning for a mass with surrounding edema. In the previous month, she had undergone ambulatory evaluation for a subacute cough that had more recently become productive of bloody sputum. Outpatient chest radiography had demonstrated a new right lung opacity, shown on subsequent CT scan imaging to be a right upper lobe (RUL) consolidation. She was prescribed a course of doxycycline, after which sputum expectoration improved but a nonproductive cough remained. Repeat thoracic imaging was pending at the time the seizure occurred. The patient had no history of chronic lung disease or recurrent infections. There were no constitutional symptoms. She did not take any home medications on a regular basis. She was a lifetime nontobacco user. She denied use of alcohol and illicit drugs. She had previously worked in a medical office but was now spending most of her time helping her husband take care of their house and property in Kingston, New York, a town of about 23,000 people in the Hudson River Valley. She was born in the United States and had not traveled recently. She had no pets. There was no history of recent dental procedures. She was transferred to our institution for neurosurgical evaluation.

Pathogenic Nocardia amamiensis infection: A rare case report and literature review

Background

To date, only six cases of Nocardia amamiensis infection have been reported, including two ocular cases, three pulmonary cases, and one disseminated case. However, no Nocardia amamiensis pulmonary infection cases have been reported in immunocompetent patients without structural pulmonary disease. This study describes a rare case and provides a detailed review of all previous cases.

Methods

A pulmonary infection caused by Nocardia amamiensis in a 64-year-old man with low-grade fever, night sweats, and weight loss was reported. All previously reported cases of Nocardia amamiensis infection were searched and reviewed.

Results

The pathogen was identified as Nocardia amamiensis using bronchoalveolar lavage fluid (BALF) mNGS, and the current case was successfully treated with trimethoprim-sulfamethoxazole (ST) monotherapy. mNGS and 16S rRNA PCR are standard tests to identify Nocardia.Conclusion: mNGS has high diagnostic performance for Nocardia amamiensis. Further studies are needed to clarify the clinical characteristics and explore more effective treatment protocols for this rare pathogen.

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.

Updated Review on Nocardia Species: 2006-2021

This review serves as an update to the previous Nocardia review by Brown-Elliott et al. published in 2006 (B. A. Brown-Elliott, J. M. Brown, P. S. Conville, and R. J. Wallace. Jr., Clin Microbiol Rev 19:259-282, 2006, https://doi.org/10.1128/CMR.19.2.259-282.2006). Included is a discussion on the taxonomic expansion of the genus, current identification methods, and the impact of new technology (including matrix-assisted laser desorption ionization-time of flight [MALDI-TOF] and whole genome sequencing) on diagnosis and treatment. Clinical manifestations, the epidemiology, and geographic distribution are briefly discussed. An additional section on actinomycotic mycetoma is added to address this often-neglected disease.

Identification of a novel drug-resistant community-acquired Nocardia spp. in a patient with bronchiectasis

A previously unknown Nocardia species was isolated from the lung tissue and bronchoalveolar lavage fluid (BALF) of a 58-year-old woman with bronchiectasis and recurrent pneumonia. This Nocardia (GZ2020^T), which grew readily in Columbia blood agar and could induce pneumonia in a mouse model, represents a novel Nocardia species, and its closest known relatives are Nocardia anaemiae NBRC 100462^T, Nocardia pseudovaccinii NBRC 100343^T and Nocardia vinacea NBRC 16497^T. However, unlike all previously known species, GZ2020^T is the first genus of Nocardia spp. that is not susceptible to multiple drugs but does show susceptibility to linezolid and moxifloxacin, and thus, GZ2020^T potentially represents a substantial health threat to patients with bronchiectasis and immunocompromised individuals. Although the original pathogen source and method of spreading remain uncertain, a mode of transmission from the environment to humans could exist. Vigilance with respect to its spread in the population and the transmission of antibiotic resistance genes in the environment should be maintained.

Detection of Nocardia by 16S Ribosomal RNA Gene PCR and Metagenomic Next-Generation Sequencing (mNGS)

In this study, the aim was to investigate the discriminatory power of molecular diagnostics based on mNGS and traditional 16S ribosomal RNA PCR among Nocardia species. A total of fourteen clinical isolates from patients with positive Nocardia cultures and clinical evidence were included between January 2017 and June 2020 in HeNan Provincial People’s Hospital. DNA extraction and 16S rRNA PCR were performed on positive cultures, and pathogens were detected by mNGS in these same samples directly. Among the 14 Nocardia isolates, four species were identified, and N. cyriacigeorgica (8 cases) is the most common species. Twelve of the 14 Nocardia spp. isolates were identified by the two methods, while two strains of N. cyriacigeorgica were not identified by mNGS. All tested isolates showed susceptibility to trimethoprim-sulfamethoxazole (SXT), amikacin and linezolid. Apart from Nocardia species, other pathogens such as Acinetobacter baumannii, Klebsiella pneumonia, Aspergillus, Enterococcus faecalis, Human herpesvirus, etc., were detected from the same clinical samples by mNGS. However, these different pathogens were considered as colonization or contamination. We found that it is essential to accurately identify species for determining antibiotic sensitivity and, consequently, choosing antibiotic treatment. 16S rRNA PCR was useful for identification of nocardial infection among species, while this technique needs the clinicians to make the pre-considerations of nocardiosis. However, mNGS may be a putative tool for rapid and accurate detection and identification of Nocardia, beneficial for applications of antimicrobial drugs and timely adjustments of medication.

Molecular characterization and improved diagnostics of Nocardia strains isolated over the last two decades at a German tertiary care center

Nocardiosis is a rare but life-threatening infection caused by aerobic Actinomycetes of the genus Nocardia particularly affecting immunocompromised hosts. The identification of Nocardia ssp. and antibiotic susceptibility testing by standard microbiological methods are incomplete and molecular techniques may improve diagnostics. We studied 39 Nocardia strains isolated from 33 patients between 2000 and 2018. Twenty-four patients (72.7 %) were immunocompromised. Whole genome sequencing (WGS) revealed a broad taxonomic range of those isolates spanning 13 different species, including four strains that belonged to three novel species based on average nucleotide identity (ANI < 95 % with currently available genome sequences). 16S rRNA gene analyses mirrored WGS results. Conventional MALDI-TOF analysis correctly identified 29 isolates at the species level (74.4 %). Our advanced protocol with formic acid and acetonitrile treatment increased identification to 35 isolates (89.7 %). Antibiotic resistance was tested using both a microdilution method and MIC strip testing. Results were in good concordance with an overall trimethoprim-sulfamethoxazole (SXT) resistance rate of 13.5 %. WGS of a SXT resistant N. farcinica isolate showed a deletion of several amino acids in a homolog of dihydropteroate synthase (FolP2) that was not seen in sensitive members of this species. Diversity of Nocardia isolates was high and involved many different species, suggesting that this taxon has broadly distributed mechanisms for infecting individuals. Widely applicable diagnostic methods including MALDI-TOF and 16S rRNA gene analyses correctly identified most strains. WGS additionally revealed molecular insights into SXT resistance mechanisms of clinical Nocardia isolates highlighting the potential application of (meta)genomic-based diagnostics in the future.

Pulmonary Nocardiosis in Pemphigus Vulgaris Patients from Tehran, Iran

OBJECTIVE

Nocardiosis is an opportunistic infection in individuals who had organ transplants and in patients with immunosuppressive diseases such as pemphigus Vulgaris (PV), diabetes mellitus, and HIV. Nocardiosis rate has not been assessed in Iranian PV patients, and this was the first study to estimate nocardiosis rate in these patients.

METHODS

In this study, 103 patients with PV were examined. BAL samples were obtained and direct smear was prepared and visualized by microscopy after PAS staining. Samples were cultured on antibiotic-containing blood and chocolate agar media. DNA extraction and PCR were performed on positive cultures, and final identification was done by 16S rRNA gene sequencing. Drug susceptibility testing was done by microbroth dilution method.

RESULTS

Four positive cultures (3.88%) were found in the samples (n = 103). According to sequence analysis, 2 isolates were identified as Nocardia cyriacigeorgica and 2 as Nocardia otitidiscaviarum and Nocardia cerradoensis. Nocardia cerradoensis was isolated from an invasive brain infection. Isolated bacteria were susceptible to majority of the tested antibiotics, except for 2 strains of Nocardia cyriacigeorgica and Nocardia cerradoensis. This was the first isolation of Nocardia cerradoensis of human infection in Asia. Patients with PV are susceptible to nocardiosis, similar to other immunocompromised patients.

CONCLUSION

Pemphigus Vulgaris is a severe autoimmune disease which is treated by a high dosage of corticosteroids. Opportunistic infections are one of the greatest challenges of these patients. One of the neglected agents of opportunistic infection in this disorder is Nocardiosis which can cause a high mortality rate in PV patients.

How do I manage nocardiosis?

BACKGROUND

Nocardiosis is a rare infection that is often difficult to treat and may be life-threatening. There is no consensus on its management.

OBJECTIVES

Our aim was to provide the current evidence for the diagnosis and management of individuals with nocardiosis, and to propose a management approach for this uncommon infection.

SOURCES

We systematically searched the medical literature on nocardiosis for studies published between 2010 and 2020 and describing ten or more individuals.

CONTENT

Nocardiosis, a primarily opportunistic infection which may occur in immunocompetent persons, most commonly involves the lungs and frequently disseminates to other sites including the central nervous system. The reference standard for Nocardia species identification is molecular biology, and the preferred method for antibiotic susceptibility testing (AST) is broth microdilution. Monotherapy seems appropriate for patients with primary skin nocardiosis or non-severe pulmonary disease; we reserve a multidrug regimen for more severe infections. Species identification and AST results are often missing at initiation of antibiotics. Trimethoprim-sulfamethoxazole is the preferred agent for initial therapy, because Nocardia is very often susceptible to this agent, and because it has been the keystone of nocardiosis treatment for years. Linezolid, to which Nocardia is almost always susceptible, may be an alternative. When combination therapy is required, the repertoire of companion drugs includes third-generation cephalosporins, amikacin and imipenem. Therapeutic modifications should take into account clinical response to initial therapy and AST results. Treatment duration of 6 months is appropriate for most situations, but longer durations are preferred for disseminated nocardiosis and shorter durations are reasonable in low-risk situations. Secondary prophylaxis may be considered in selected individuals with permanent immunosuppression.

IMPLICATIONS

We hereby provide the clinician with an easy-to-use algorithm for the management of individuals with nocardiosis. We also illuminate gaps in evidence and suggest future research directions.

Nocardia Infections: Ten Years Experience from a Tertiary Health Care Center in North India (2007-2016)

BACKGROUND

Nocardia species are important cause of infections in humans but are underreported due to missed diagnosis as well as misdiagnosis. Majority of the literature on these infections consists of case reports or series with few articles describing high number of cases.

OBJECTIVE

To study the epidemiology of Nocardia infections in a tertiary care center.

MATERIALS AND METHODS

This retrospective observational study was done in a tertiary care centre of North India over a period of 10 years (2007-2016). The detection of Nocardia spp. from clinical specimens was done by conventional methods viz. direct microscopy (Gram's stain, modified Ziehl -Neelsen stain [1%], KOH examination) and culture.

RESULTS

A total of 25 cases of nocardiosis were diagnosed during the study period. The mean age of the patients was 50.9 years (range 30-72 years) with a male:female ratio of 3:2. The site of disease in these patients included pulmonary (n=18), cutaneous (n=4), perinephric abscess (n=1), ocular (n=1) and bone (n=1). Risk factors associated were underlying lung disease (n=11), smoking (n=7), diabetes (n=5) and steroid therapy (n=4) in pulmonary nocardiosis, iatrogenic (n=1) and leprosy (n=1) in cutaneous nocardiosis, diabetes in perinephric abscess and cataract surgery in ocular nocardiosis. Culture was positive in 12/25 (48%) patients for Nocardia spp. Direct microscopy was positive in 22 patients. We wish to highlight that meticulous observation of KOH wet mount examination helped in clinching the diagnosis of Nocardiosis in 3 cases which were earlier missed by other methods.

CONCLUSION

Good communication with the clinician alongside a meticulous effort in the laboratory is essential for appropriate diagnosis and management of these cases.

Invasive Nocardiosis: Disease Presentation, Diagnosis and Treatment - Old Questions, New Answers?

Nocardia spp. is an environmental filamentous Gram-positive bacterium that may cause infections in humans and, despite recent progress, many challenges remain regarding the management of nocardiosis. This review aims at describing most recently published data regarding the diagnosis, treatment and follow-up of patients with invasive nocardiosis. As nocardiosis mainly affects patients with cell-mediated immunity defects, a comprehensive workup is mandatory in case of invasive nocardiosis occurring in ”apparently healthy patients”. Indeed, invasive nocardiosis might reveal an unknown primary immunodeficiency or the presence of anti-GM-CSF autoantibodies. Even if the diagnosis of nocardiosis mostly relies on direct examination and bacterial culture, a genus-specific PCR may be used for the detection of Nocardia, when directly performed on a clinical sample. Brain imaging should always be performed, even in the absence of neurological symptoms. Cotrimoxazole (trimethoprim/sulfamethoxazole), linezolid, parenteral cephalosporins, carbapenems and amikacin may be used as initial antibiotics to treat nocardiosis. Cotrimoxazole or linezolid can be used as monotherapy in selected patients without brain involvement. Although treatment duration has historically been set to at least 6 months in the absence of central nervous system involvement, shorter durations (<120 days) seem to be associated with a favourable outcome.

Nocardiosis in glomerular disease patients with immunosuppressive therapy

Background

Glomerular disease patients have a high risk of infection, which contributes to the progression of disease per se and mortality, especially in those with long-term use of glucocorticoids and (or) immunosuppressive agents. Cases of sporadic nocardiosis have been reported in glomerular disease patients, and this observation was conducted to comprehensively understand the manifestations of and treatments for nocardiosis, which is commonly misdiagnosed as pneumonia or tuberculosis or even as lung cancer or metastatic tumors in glomerular disease patients.

Methods

We reviewed the demographic characteristics, laboratory abnormalities, radiological features, and treatments of 7 patients with nocardiosis and glomerular disease receiving steroids and immunosuppression therapy at the nephrology department of the Second Xiangya Hospital between 2012 and 2019.

Results

It was found that all 7 patients had been receiving methylprednisolone for renal disease at a median dose of 20 mg per day and a median duration of 4 months before developing nocardiosis. There were 4 males and 3 females, and the median age was 52.14 years. All 7 patients had hypoalbuminemia at the time of admission. In addition, various cystic abscesses in the subcutaneous tissue, with or without lung and brain involvement, were observed in these patients. Encouragingly, body temperatures returned to normal, and subcutaneous abscesses diminished or disappeared with compound sulfamethoxazole treatment alone or in combination with linezolid, imipenem and mezlocillin/sulbactam.

Conclusions

It was shown that multisite abscesses, including subcutaneous, pulmonary and cerebral abscesses, were the common manifestations of nocardiosis in glomerular disease patients. Sulfonamide was the first-line antibiotic therapy for nocardiosis, and combinations of other antibiotics were also needed in some serious cases.

Disseminated Nocardia infection with a lesion occupying the intracranial space complicated with coma: a case report

Background

Disseminated Nocardia infection is a disease that is easily overlooked in patients with lesions occupying the intracranial space complicated with coma. Early diagnosis and treatment are crucial.

Case presentation

A 65-year-old man was admitted to the First Affiliated Hospital of Zhejiang University in October 2018 with weakness in the right limbs for 3 days and altered consciousness for 1 day. Five months earlier, he had been diagnosed with membranous kidney disease and had received cyclophosphamide and prednisone. At admission, the white blood cell count was 1.37 × 10¹⁰/L (with 86.4% neutrophils), and C-reactive protein was 115.60 mg/L. Imaging examinations revealed a lesion occupying the intracranial space, lung infection, and multiple abscesses in the rhomboid muscle. The abscesses were drained. Pus culture confirmed Nocardia cyriacigeorgica infection. With antibiotics and vacuum-sealed drainage of the back wound, the patient improved and was discharged from the hospital.

Conclusions

This case report shows that infection should be considered during the differential diagnosis of lesions in the intracranial space, especially in patients receiving immunosuppressive treatment. In patients with disseminated N. cyriacigeorgica infection, combination antibiotic therapy and surgical drainage of localised abscesses can be effective.

Clinical correlates of nocardiosis

Nocardia is an opportunistic pathogen that most frequently affects the lungs. Evidence is limited regarding the risk factors for nocardiosis. The current study assessed clinical correlates of nocardiosis. A retrospective study was conducted based on medical records of consecutive adult patients (N = 60) with nocardiosis hospitalized during 2007–2018 at a tertiary hospital in central Israel. A matched comparison group of 120 patients was randomly selected among hospitalized patients with community-acquired pneumonia. Multivariable conditional logistic regression models were fitted. Immunosuppressive pharmacotherapy was positively associated with nocardiosis (matched odds ratio [OR] 4.40, 95% confidence interval [CI] 2.25–8.62, p < 0.001), particularly corticosteroid therapy (matched OR 4.69, 95% CI 2.45–8.99, p < 0.001). Systemic corticosteroid therapy was strongly associated with pulmonary nocardiosis (matched OR 5.90, 95% CI 2.75–12.66, p < 0.001). The positive association between solid organ transplantation and nocardiosis was attenuated following adjustment for systemic corticosteroids in a multivariable model. The association between corticosteroid therapy and nocardiosis appeared stronger in patients with chronic pulmonary disease (OR 5.74, 95% CI 2.75–12.66, p < 0.001) than in the pooled analysis of all nocardiosis cases. In conclusion, corticosteroid therapy was strongly correlated with nocardiosis, particularly among individuals with chronic pulmonary disease and in pulmonary nocardiosis.

[Emerging bacteria in cystic fibrosis and non-cystic fibrosis bronchiectasis from a microbiologist's perspective]

INTRODUCTION

Common major pathogens like Pseudomonas aeruginosa are identified in the airways of patients with cystic fibrosis (CF) and non-CF bronchiectasis. However, other opportunistic bacterial pathogens like Achromobacter xylosoxidans complex, Stenotrophomonas maltophilia and non-tuberculous mycobacteria are currently emerging in CF and are also reported in non-CF bronchiectasis.

BACKGROUND

The emergence of opportunistic bacterial pathogens has been recognized in CF through annual national reports of sputum microbiology data. Despite common factors driving the emergence of bacteria identified in CF and non-CF bronchiectasis patients, bronchiectasis registries have been created more recently and no longitudinal analysis of recorded microbiological data is currently available in the literature, thereby preventing the recognition of emerging bacteria in patients with non-CF bronchiectasis.

OUTLOOK

A longitudinal follow-up of microbiological data is still needed in non-CF bronchiectasis to identify emerging opportunistic bacterial pathogens. Homogeneity in practice of sputum microbiological examination is also required to allow comparative analysis of data in CF and non-CF bronchiectasis.

CONCLUSION

Bacterial pathogens recognized as emerging in CF have to be more carefully monitored in non-CF bronchiectasis in view of their association with deterioration of the lung disease.

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.

Characteristics of nocardiosis patients with different immune status from a Chinese tertiary general hospital during 8-year period: A STROBE-compliment observational study

Nocardia is an opportunistic pathogen from environment, which is generally thought to infect immunosuppressed patients (ISPs), but recent studies showed it could also cause infections in immunocompetent patients (ICPs).The aim of this study was to compare the clinical characteristics, patients' outcome, Nocardia species' identification, and antibiotic susceptibility profiles of nocardiosis between ICPs and ISPs.The detailed clinical data were collected from all the nonrepetitive nocardiosis patients during 2011 and 2018, from a tertiary general hospital in Beijing, China. Then each Nocardia isolate was identified to species level by DNA sequencing. The antibiotic susceptibility testing was performed by E test method, and interpreted following CLSI M24 document. The clinical and microbiological characteristics between ICPs and ISPs were compared statistically.A total of 23 nonrepetitive nocardiosis patients with detailed clinical data were enrolled in this study. Among them, 9 were ICPs and 14 were ISPs. All the skin and soft tissue infections occurred in ICPs (33.3% vs 0%, P < .05). Bronchiectasis occurred more frequently in ICPs (44.4% vs 21.4%), whereas chronic kidney diseases and coinfection with aspergillosis occurred more frequently in ISPs (35.7% vs 0%, 35.7% vs 0%, respectively), although they did not reach the statistical significance. There were no significant differences in other clinical characteristics, Nocardia species' identification, and antibiotic susceptibility between ISPs and ICPs (P > .05).Nocardiosis could occur in both ISPs and ICPs. Skin and soft tissue infection and bronchiectasis occurred more frequently in ICPs. Chronic kidney diseases and co-infection with aspergillosis occurred more frequently in ISPs. These characteristics should be noticed by physicians in diagnosis of nocardiosis.

Bronchiectasis update

PURPOSE OF REVIEW

Bronchiectasis, once thought to be an orphan disease, is being diagnosed with increased frequency in the United States and around the world. The present review aims to provide an update on recent publications on the diagnosis and management of bronchiectasis.

RECENT FINDINGS

Two large bronchiectasis patient registries have published initial reports regarding demographics and other patient data in 2017. Updates on the microbiology, microbiome, and inflammation in patients with bronchiectasis are clarifying the complexities of airway infection in this disease. A consensus definition of 'exacerbation' in bronchiectasis has been agreed upon this year. Reports on novel treatments, including the repurposing of older therapies, have also been published in 2016-2017. A new European guideline for the management of adult bronchiectasis is also now available.

SUMMARY

Bronchiectasis, a resurgent disease, is now being better defined with a rapidly expanding portfolio of demographic, clinical, and therapeutic research and publications.

Updates on Nocardia Skin and Soft Tissue Infections in Solid Organ Transplantation

PURPOSE OF REVIEW

Due to their immunocompromised status, solid organ transplant (SOT) recipients are at risk for Nocardia infections. These infections often necessitate early invasive diagnostics alongside prolonged, often combination antimicrobial therapy. This review summarizes the importance of this pathogen in skin and soft tissue infections (SSTIs) in SOT recipients inclusive of recently reported cases in the literature and an update on the epidemiology, diagnostics, and management.

RECENT FINDINGS

Six studies with 13 isolated SSTIs due to Nocardia have been published in the last 5 years in SOT recipients. The most common underlying type of transplant was kidney and time from transplantation to infection varied from 6 months to 16 years. Misdiagnosis was frequent. Available identified species included N. brasiliensis (2), N. farcinica (2), N. flavorosea (1), N. abscessus (1), N. anaemiae (1), N. asteroides (1), N. nova (1), and N. vinacea (1). Treatment choice and duration varied widely, and trimethoprim-sulfamethoxazole was utilized most often with no documented infection relapse. Nocardia SSTIs can occur both in isolation and as a component of a disseminated infection. Overall, isolated Nocardia SSTIs are uncommon in SOT recipients and are often initially misdiagnosed. They present multiple challenges to the clinician including evaluation for potential co-pathogens and/or non-infectious processes and ruling out the presence of disseminated infection. While trimethoprim-sulfamethoxazole remains the agent of choice for management of most isolated SSTIs, therapy must be tailored to the individual patient based on species-specific susceptibility patterns and formal susceptibility testing, site(s) of infection, and patient tolerability.

Microbiological Progress in Patients with Bronchial Infection with <b><i>Pseudomonas aeruginosa</i></b> Treated with Nebulised Colistin

<b><i>Background:</i></b> Inhaled antibiotics allow the delivery of higher drug concentrations at the site of infection without the systemic adverse effects observed with the use of parenteral or oral antibiotics. These antibiotics have shown to decrease the number of exacerbations, reduce bacterial load or improve pulmonary function in several chronic respiratory conditions. <b><i>Objectives:</i></b> The aim of this study was to describe changes in the bacteriology of sputum in patients with chronic bronchial infection with <i>Pseudomonas aeruginosa</i> treated with nebulised colistin. <b><i>Material and Methods:</i></b> All patients with chronical infection with <i>P. aeruginosa</i> treated with nebulised colistin attending a day care unit during a 5-year (January 2010 to December 2014) period were included. Repeated-measures <i>t</i> tests were used to assess whether the introduction of colistin was associated with changes in the number of exacerbations or the length of the hospitalisations. <b><i>Results:</i></b> Treatment with colistin was associated with a decrease in the number of ambulatory exacerbations (1.87–1.1, <i>p</i> = 0.007), of hospital exacerbations (1.3–0.7, <i>p</i> = 0.010) and of length of stay (15.7–8.6 days, <i>p</i> = 0.005). There was no linear trend in the proportion of isolate Enterobacteriaceae, gram-positive cocci, <i>Haemophilus influenzae</i> or fungi. Isolation of Enterobacteriaceae within 1 year after the beginning of the treatment with nebulised colistin was associated with an increase in the number of ambulatory exacerbations (incidence rate ratio 1.99, 95% CI 1.05–3.79). <b><i>Conclusions:</i></b> Nebulised colistin was effective in the treatment of chronic infection with <i>P. aeruginosa,</i> and no significant changes in the microbiological evolution were observed. Isolation of Enterobacteriaceae within 1 year after the beginning of the treatment with nebulised colistin was associated with an increase in the number of exacerbations.

Manifestations and outcomes of nocardia infections: Comparison of immunocompromised and nonimmunocompromised adult patients

Nocardia is a ubiquitous environmental pathogen that causes infection primarily following inhalation into the lungs. It is generally thought to cause infection primarily in immunocompromised patients, but nonimmunocompromised individuals are also at risk of infection. We sought to compare risk factors, clinical manifestations, diagnostic approach, treatment, and mortality in immunocompromised and nonimmunocompromised adults with nocardiosis.We studied all adults with culture-proven Nocardia infection at a tertiary care hospital from 1994 to 2015 and compared immunocompromised with nonimmunocompromised patients. The immunocompromised group included patients who had a solid organ transplant, hematopoietic cell transplant (HCT), hematological or solid tumor malignancy treated with chemotherapy in the preceding 90 days, inherited immunodeficiency, autoimmune/inflammatory disorders treated with immunosuppressive agents, or high-dose corticosteroid therapy for at least 3 weeks before the diagnosis of nocardiosis.There were 112 patients, mean age 55 ± 17 years; 54 (48%) were women. Sixty-seven (60%) were immunocompromised, and 45 (40%) were nonimmunocompromised. The lung was the site of infection in 54 (81%) immunocompromised and 25 (55%) nonimmunocompromised patients. Pulmonary nocardiosis in immunocompromised patients was associated with high-dose corticosteroids, P = .002 and allogeneic HCT, P = .01, and in nonimmunocompromised patients with cigarette smoking, bronchiectasis, and other chronic lung diseases, P = .002.Cavitation occurred only in the immunocompromised group, P < .001. Disseminated infection was more common in the immunocompromised, P = .01, and was highest in solid organ transplant recipients, P = .007. Eye infection was more common in nonimmunocompromised patients, P = .009. Clinical signs and symptoms did not differ significantly between the 2 groups. The initial treatment for most patients in both groups was trimethoprim-sulfamethoxazole with or without a carbapenem. All-cause 1-year mortality was 19%; 18 (27%) immunocompromised and 3 (7%) nonimmunocompromised patients died, P = .01.Immunocompromised patients with nocardiosis had more severe disease and significantly higher mortality than nonimmunocompromised patients, but clinical presentations did not differ.

Pulmonary Reinfection by Nocardia in an Immunocompetent Patient with Bronchiectasis

Pulmonary reinfection by Nocardia has been rarely reported. We describe a case of pulmonary reinfection by Nocardia in an immunocompetent patient. An 82-year-old immunocompetent woman with bronchiectasis presented with exacerbation of cough. She had a history of pulmonary nocardiosis three years earlier. At that time, Nocardia species were cultured from the sputum and identified as N. cyriacigeorgica with 16S ribosomal RNA gene sequencing. In the present episode, cultures of sputum and bronchial washing specimens grew N. beijingensis, which was identified with 16S ribosomal RNA gene sequencing. Pulmonary reinfection by different Nocardia species can occur in immunocompetent patients.

Nocardia infections in the transplanted host

BACKGROUND

Nocardia are uncommon pathogens that disproportionately afflict the immunocompromised host. Epidemiology and outcome data of Nocardia infections in transplant recipients are limited.

METHODS

We performed a retrospective chart review of all patients at Duke University Hospital with a history of solid organ transplant (SOT) or hematopoietic cell transplant (HCT) and at least one positive culture for Nocardia between 1996 and 2013. Our aim was to describe the epidemiology and outcomes of Nocardia infections in the transplanted host.

RESULTS

During the 18-year study period, 51 patients (14 HCT and 37 SOT recipients) had Nocardia infection. Nocardia incidence was stable during the study period in all populations except heart transplants, whose incidence declined. Infection occurred earlier in the HCT group than the SOT group (median time to diagnosis of 153 and 370 days, respectively). In both groups, the most common site involved was the lung. Outcomes were overall poor, especially in the HCT group with a cure rate of 29%. Heart transplant recipients had significantly better overall survival (P < .05) than other patients. Trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis did not provide complete protection from Nocardia infections, nor did it appear to select for resistant Nocardia isolates.

CONCLUSIONS

Infections with Nocardia are typically a late post-transplant complication. The use of TMP-SMX prophylaxis was not associated with TMP-SMX-resistant Nocardia. Overall outcomes remain poor.