Susceptibility of 186 Nocardia sp. isolates to 20 antimicrobial agents. Antimicrob Agents Chemother. 2011;55:2995-2998. [PMID: 21402847 DOI: 10.1128/aac.01279-10]

Liver cirrhosis complicated with pulmonary Nocardia infection: A case report and literature review

RATIONALE

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

PATIENT CONCERNS

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

DIAGNOSES

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

INTERVENTIONS

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

OUTCOMES

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

LESSONS

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

Case report: Metagenomic next-generation sequencing for the diagnosis of rare Nocardia aobensis infection in a patient with immune thrombocytopenia

Background

Nocardiosis poses a diagnostic challenge due to its rarity in clinical practice, non-specific clinical symptoms and imaging features, and the limitations of traditional detection methods. Nocardia aobensis (N. aobensis) is rarely detected in clinical samples. Metagenomic next-generation sequencing (mNGS) offers significant advantages over traditional methods for rapid and accurate diagnosis of infectious diseases, especially for rare pathogens.

Case presentation

A 52-year-old woman with a history of immune thrombocytopenia for over 2 years was hospitalized for recurrent fever and cough lasting for 10 days. Her initial diagnosis on admission was community-acquired pneumonia, based on chest computed tomography findings of lung inflammation lesion. Empirical treatment with moxifloxacin and trimethoprim-sulfamethoxazole (TMP-SMZ) was initiated. However, her condition failed to improve significantly even after 1 week of treatment. Bronchoalveolar lavage fluid (BALF) subjected to mNGS revealed the presence of N. aobensis, resulting in a diagnosis of pulmonary nocardiosis caused by N. aobensis. This diagnosis was also supported by Sanger sequencing of the BALF. After adjusting the antibiotic regimen to include TMP-SMZ in combination with imipenem, the patient's condition significantly improved. She was finally discharged with instructions to continue oral treatment with TMP-SMZ and linezolid for 6 months. The patient's first follow-up 1 month after discharge showed good treatment outcomes but with obvious side effects of the drugs. Consequently, the antibiotic regimen was changed to doxycycline, and the patient continued to improve.

Conclusion

We report the first detailed case of pulmonary nocardiosis caused by N. aobensis diagnosed by mNGS. mNGS could be an effective method that facilitates early diagnosis and timely decision-making for the treatment of nocardiosis, especially in cases that involve rare pathogens.

Secreted protein NFA47630 from Nocardia farcinica IFM10152 induces immunoprotective effects in mice

PURPOSE

Nocardia is emerging as a common and easily neglected cause of both healthcare- and occupation-associated infections worldwide, however, human vaccines for Nocardia prevention are not yet available. In this study, we aimed to evaluate the immunoprotective effect of the NFA47630 protein, a secreted protein abundant in the N. farcinica IFM10152 supernatant.

METHODS

Conservation and characteristics of nfa47630 were analyzed by PCR and bioinformatics. Then recombinant NFA47630 protein was cloned, expressed and purified for further antigenicity analysis. Subsequently, the ability to activate innate immunity was evaluated by examining the phosphorylation status of the MAPK signaling pathway and cytokine levels. Finally, the protective effect was evaluated on rNFA47630-immunized mice.

RESULTS

nfa47630 was conserved in N. farcinica strains with good antigenicity. The rNFA47630 protein was expressed under the optimal conditions of 0.2 mM IPTG, 28 °C, and it can be recognized by anti-N. farcinica and anti-N. cyriacigeorgica sera, but not anti-N. asteroids, anti-N. brasiliensis, anti-N. nova and anti-Mycobacterium bovis sera. It can upregulate the phosphorylation status of ERK, JNK, P38 and the cytokine levels of TNF-α, IL-10, IL-12, and IFN-γ. In addition, mice immunized with rNFA47630 protein exhibited higher antibody titers, greater bacterial clearance ability, milder organ infection, and higher survival rates than PBS-immunized mice.

CONCLUSIONS

Our data demonstrate that NFA47630 is a potential vaccine candidate for defending against N. farcinica infection.

Application of MALDI-TOF mass spectrometry for identification of Nocardia species

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.

Disseminated Nocardia nova in a child with relapsed acute lymphoblastic leukemia: a case report

BACKGROUND

Nocardiosis is a rare infection that typically results from inhalation of or inoculation with Nocardia organisms. It may cause invasive disease in immunocompromised patients. This case describes nocardiosis with bacteremia and pulmonary involvement in a child with a hematologic malignancy.

CASE PRESENTATION

A boy with testicular relapsed acute lymphoblastic leukemia with marrow involvement presented with sudden onset of fever, body aches, headaches, chills, and moderate respiratory distress during continuation 2 chemotherapy. Radiographic imaging demonstrated consolidation and ground glass opacities in bilateral lower lungs. Central line blood cultures grew Nocardia nova complex, prompting removal of the central line and initiation of triple therapy with imipenem-cilastatin, linezolid, and trimethoprim-sulfamethoxazole with rapid improvement of symptoms. Antibiotic susceptibilities showed a multidrug-susceptible isolate. The patient is anticipated to remain on trimethoprim-sulfamethoxazole for at least 12 months.

CONCLUSIONS

In an immunocompromised child, blood cultures, chest imaging, and head imaging can aid in the diagnosis of disseminated nocardiosis. Long-term antibiotic therapy is necessary, guided by the organism and simplified with the results of antimicrobial susceptibility testing.

Rare occurrence of pulmonary coinfection involving Aspergillus fumigatus and Nocardia cyriacigeorgica in immunocompetent patients based on NGS: A case report and literature review

RATIONALE

In our search on PubMed, we found that reports of co-infections involving Aspergillus fumigatus and Nocardia cyriacigeorgica in the literature are notably scarce. Most cases have been documented in patients with compromised immune systems or underlying pulmonary conditions. In contrast, our patient did not present with any of these risk factors. Furthermore, there have been no recent incidents such as near-drowning or other accidents in the patient history. To the best of our knowledge, this case represents a hitherto unreported clinical scenario. To enhance comprehension, we conducted a comprehensive literature review by compiling a total of 20 case reports (spanning from 1984 to 2023) on co-infections involving Aspergillus and Nocardia species, retrieved from PubMed.

PATIENT CONCERNS AND DIAGNOSIS

Chest CT revealed the presence of multiple nodules and clustered high-density shadows in both lungs. Bronchoscopy revealed mucosal congestion and edema in the apical segment of the right upper lobe of the lung, along with the presence of 2 spherical polypoid new organisms. The pathological analysis reported severe chronic inflammation with evidence of Aspergillus within the tissue. Next-Generation Sequencing of bronchoalveolar lavage fluid revealed the presence of reads corresponding to A fumigatus and N cyriacigeorgica. Positive cultures for A fumigatus and the Nocardia genus were yielded by prolonging the incubation of samples in the microbiology laboratory.

INTERVENTIONS

Treatment with voriconazole for A fumigatus and sulfamethoxazole-trimethoprim for N cyriacigeorgica infection was given.

OUTCOMES

The patient improved and was discharged. After 6 months of telephone follow-up, the patient reported no clinical symptoms, discontinued the medication on his own.

LESSONS

A fumigatus and N cyriacigeorgica can manifest as a co-infection in immunocompetent patients. Clinicians should prioritize the significant advantages and value of NGS in detecting rare and mixed pathogens associated with pulmonary infections.

Clinical characteristics, outcomes, and factors associated with mortality in Nocardia pneumonia: 18 years' real-world data from a tertiary care hospital in Karachi, Pakistan

BACKGROUND

Pulmonary nocardiosis is a rare pulmonary infection with high morbidity and mortality. Limited real-world data on pulmonary nocardiosis patients are available from developing countries like Pakistan.

METHODS

This retrospective observational study was conducted at the Aga Khan University Hospital, Karachi, Pakistan, from August 2003 to June 2020. Demographics, immune status, underlying diseases, laboratory data, treatment, and outcomes of all nocardiosis patients were recorded in predesigned proforma.

RESULTS

Sixty-six patients with smear/culture-proven pulmonary nocardiosis were identified. Most patients (83.3%) were treated with trimethoprim-sulfamethoxazole alone or in combination with other medicines. The overall mortality rate in our study was 33.3% (n = 22/66). Factors significantly associated with mortality were respiratory failure (p < 0.001), raised procalcitonin levels (p = 0.01), concomitant fungal infections (p = 0.01), concomitant TB (p = 0.03), and patients on combination therapy (p < 0.001). Respiratory failure (odds ratio [OR] 46.94 [95% confidence intervals [CI]: 5.01-439.03] p < 0.001), concomitant fungal infection (OR 17.09 [95% CI: 1.47-197.88] p- = 0.02) and patients on combination therapy (OR 6.90 [95% CI: 1.23-38.61] p = 0.02) were also identified as independent risk factors for mortality on multivariate analysis.

CONCLUSIONS

This study provides essential information on the clinical characteristics and risk factors, outcomes, and factors associated with mortality for pulmonary nocardial infections.

First Report of Clivus Osteomyelitis Caused by Nocardia veterana in a Lung Transplant Recipient

Nocardia species have been implicated as a cause of pulmonary, cutaneous, ocular, and disseminated central nervous system disease. Dissemination to the bones, commonly the spine, has also been described in the literature. However, isolated osteomyelitis of the skull base is rare. Additionally, advances in the use of molecular techniques have identified many new Nocardia species, including Nocardia veterana that was thought to be clinically insignificant when it was first identified. Here, we report the clinical features and treatment approach for a lung transplant patient who developed N. veterana clivus osteomyelitis secondary to sphenoid sinusitis. It is the first case of skull base osteomyelitis caused by this rare species of Nocardia.

Nodular Cutaneous Lesions in Immune-Compromised Hosts as a Clue for the Diagnosis of Disseminated Nocardiosis: From Bedside to Microbiological Identification

BACKGROUND

Nocardia is a group of ubiquitous bacteria known to cause opportunistic infections in immunocompromised hosts, including those affected by malignancies and solid-organ or hematopoietic stem cell transplants. Pulmonary involvement, occurring in two-thirds of cases, is the most frequent presentation. Diagnosis might be challenging both because of microbiological technical issues, but also because of the variability of organ involvement and mimicry.

METHODS

We describe four cases of disseminated nocardiosis caused by N. farcinica observed between September 2021 and November 2021 in immune-compromised hosts presenting with nodular cutaneous lesions that had raised a high degree of clinical suspect and led to microbiological identification through MALDI-TOF MS.

RESULTS

Cutaneous involvement is typically reported in immunocompetent hosts with primary cutaneous nocardiosis with multiple forms of manifestation; nonetheless, disseminated nocardiosis rarely involves the skin and subcutaneous tissues, and this occurs as a result of metastatic spread. Our cases were disseminated nocardiosis in which the metastatic cutaneous involvement, even if rare, provided a clue for the diagnosis.

CONCLUSIONS

The pathomorphosis of disseminated nocardiosis may have changed in the current years with more rapid spread due to advanced immunosuppression. For this reason, after clinical suspicion, the prompt start of an active targeted therapy based on rapid microbiological identification might potentially open the way to hopeful results, even in the most immune-compromised patients.

Immunoprotective Analysis of the NFA49590 Protein from Nocardia farcinica IFM 10152 Demonstrates Its Potential as a Vaccine Candidate

Nocardia is emerging as a serious and easily neglected pathogen in clinical practice with multidrug resistance that extends the treatment period for months or even years. This has led to the investigation of a vaccine approach to prevent Nocardia infections. However, studies on the protective proteins of Nocardia have not yet been carried out. In the present work, over 500 proteins in the supernatant of N. farcinica IFM10152 were identified by LC−MS/MS. In silico analysis of these proteins with a high content (score > 2000) predicted that NFA49590 was one of the conserved proteins in N. farcinica strains with potential antigenicity. After the rNFA49590 protein was cloned and expressed in E. coli (DE3) and purified using a Ni-NTA column, its good antigenicity was confirmed with sera from mice immunized with different Nocardia species by Western blot. Then we confirmed its ability to activate innate immunity by examining the phosphorylation status of ERK1/2, JNK, p38, and p65 and the cytokine levels of IL-6, TNF-α, and IL-10. Finally, we evaluated its immunoprotective effect in BALB/c mice, and we found that mice immunized with rNFA49590 protein exhibited high antibody titers, enhanced bacterial clearance ability, and generated robust protective effects from the N. farcinica challenge. These results offer strong support for the use of NFA49590 protein as a vaccine candidate and open the possibilities for the exploration of a large array of immunoprotective proteins.

Identification of Streptomyces spp. in a clinical sample: always contamination? Results of a French Retrospective Study

Background

Streptomyces are environmental Gram-positive bacilli that can cause ubiquitous mycetoma and, more rarely, invasive infections. We describe the clinical relevance of Streptomyces spp. identified in human samples and characteristics of patients with invasive Streptomyces infections.

Methods

We conducted a retrospective (2006-2017) study of Streptomyces isolates identified in clinical samples in French microbiology laboratories. Streptomyces genus was confirmed by a specific 16S rRNA PCR and antibiotic susceptibility testing was performed by disk diffusion and trimethoprim-sulfamethoxazole MIC (E-test) if resistance was suspected. Patient characteristics, treatment and outcomes were collected. Invasive infection was defined as a positive culture from a sterile site with signs of infection but without cutaneous inoculation.

Results

Of 137 Streptomyces isolates, all were susceptible to amikacin (113/113) and linezolid (112/112) and 92.9% to imipenem (105/113). Using disk diffusion, 50.9% (57/112) of isolates were susceptible to trimethoprim-sulfamethoxazole but most of apparently-resistant isolates (25/36, 69.4%) tested by E-test were ultimately classified as susceptible. Clinical data were obtained for 63/137 (45.9%) isolates: 30 (47.6%) invasive infections, 8 (12.7%) primary cutaneous infections, 22 (34.9%) contaminations, 3 (4.7%) respiratory colonization. Patients with invasive infection were more frequently receiving corticosteroids than patients without invasive infection (11/30, 36.7% vs 2/25, 8.0%, P = 0.03) and at 6-months follow-up, 14 of them were cured, three had relapsed, four were dead and nine were lost to follow-up.

Conclusions

Half of the clinical samples that grew Streptomyces were from patients with invasive infection. In that case, antimicrobial therapy should include one or two antibiotics among linezolid, amikacin or imipenem.

Epidemiology and Antimicrobial Resistance Profiles of the Nocardia Species in China, 2009 to 2021

The genus Nocardia includes ubiquitous environmental saprophytes and the most frequently isolated aerobic actinomycete human pathogen responsible for localized or disseminated infection. Herein, the species distribution and antimicrobial susceptibility profiles of 441 nonrepetitive Nocardia strains are reported, collected from 21 provinces/cities in China over 13 years (from 2009 to 2021). These isolates were identified to species level by mass spectrometry or targeted DNA sequencing. The susceptibility profiles of Nocardia species for 15 antibiotics were determined by the broth microdilution method. Among these Nocardia isolates, Nocardia farcinica was the most commonly isolated species (39.9%, 176 of 441), followed by Nocardia cyriacigeorgica (28.6%, 126), Nocardia abscessus (6.6%, 29), and Nocardia otitidiscaviarum (5.9%, 26). Furthermore, 361 Nocardia strains (81.9%) were collected from lower respiratory tract (sputum, lung tissue, and bronchoalveolar lavage fluid), 50 (11.3%) were collected from skin and soft tissues, 9 were collected from blood, 9 were collected from eye, 4 were collected from cerebrospinal fluid and brain abscesses, and 2 were collected from pleural effusion. All of the Nocardia strains were susceptible to linezolid, followed by amikacin (99.3%) and trimethoprim-sulfamethoxazole (TMP-SMX) (99.1%). The antibiotic resistance profiles of other antibiotics varied tremendously among different Nocardia species. This demonstrated that accurate species identification and/or antibiotic susceptibility testing should be performed before the usage of these antibiotics. In summary, this is the largest study on the species and antibiotic resistance profiles of the genus Nocardia circulating in China, and our data will contribute to a better understanding of clinical nocardiosis.

IMPORTANCE The genus Nocardia has the potential to cause nocardiosis, which might be underrecognized and underdiagnosed. Herein, the demographical features of 441 nonrepetitive nocardiosis cases and species distribution of their Nocardia strains in China, 2009 to 2021, are summarized. The susceptibility profiles for 15 antibiotics against all of the above Nocardia strains were also determined by the broth microdilution method. To date, this is the largest study on the genus Nocardia contributing to nocardiosis in China. Our study will be helpful for understanding the species diversity of Nocardia isolates distributed in China and for decision-making in the context of nocardiosis diagnosis and treatment.

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.

MLSA phylogeny and antimicrobial susceptibility of clinical Nocardia isolates: a multicenter retrospective study in China

Background

With the increase of detection rate and long treatment period, nocardiosis has become a noticeable problem in China. However, there are limited large-scale studies on the epidemiology and antimicrobial susceptibility profiles of clinical Nocardia spp. in China. The present study aimed to explore the species distribution and drug susceptibility pattern of 82 clinical Nocardia isolates from three tertiary hospitals in China by multilocus sequence analysis (MLSA) and broth microdilution (BMD) method.

Results

Pulmonary nocardiosis (90.2%) was the most common clinical presentation of infection. N. cyriacigeorgica (n = 33; 40.2%) and N. farcinica (n = 20; 24.4%) were the most frequently encountered Nocardia species, followed by N. otitidiscaviarum (n = 7; 8.5%), N. abscessus (n = 5; 6.1%), N. asiatica (n = 4; 4.9%), and N. wallacei (n = 4; 4.9%). Trimethoprim/sulfamethoxazole (SXT) remained high activity against all Nocardia isolates (susceptibility rate: 98.8%). Linezolid and amikacin were also highly active; 100 and 95.1% of all isolates demonstrated susceptibility, respectively. Except for N. otitidiscaviarum, all the Nocardia isolates exhibited high susceptibility rates to imipenem. The resistance rates of all isolates to clarithromycin and ciprofloxacin were 92.7 and 73.2%, respectively, but the resistance rate of N. farcinica to ciprofloxacin was only 25%.

Conclusions

The clinically isolated Nocardia spp. had diverse antimicrobial susceptibility patterns, which were similar to the reports by other groups elsewhere, but some differences were also observed, mainly including imipenem and ciprofloxacin. According to this study, SXT still can be the first choice for empirical therapy due to the low resistance rate. Linezolid can be chosen when a patient is allergic to SXT, and amikacin and imipenem can be the choice in a combination regimen.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02412-x.

Treatment of Nocardial Brain Abscess in a Patient With Systemic Lupus Erythematosus and Idiopathic Thrombocytopenic Purpura: Case Report and a Review of the Literature

Brain abscesses due to Nocardia species account for 1-2% of all cerebral abscesses, often in immunosuppressed individuals, with a mortality three times higher than other cerebral abscesses. Early diagnosis and management are vital for good outcomes. We report a case of a right frontal Nocardia brain abscess in an immunosuppressed 38-year-old female. She presented with headaches, confusion, memory deficits, and personality change. She remained systemically well, with normal inflammatory markers. She underwent two open surgical drainages, with excision of the abscess wall. She made an excellent recovery with minimal edema and no contrast enhancement on imaging at eight weeks postoperatively. Management of Nocardia brain abscess includes a prompt diagnosis with direct microscopic examination and initiation of correct antibiotic therapy for good outcomes. We recommend open surgical resection, including excision of the abscess wall, followed by long-term antimicrobial therapy, to enhance the rate of recovery.

Molecular identification and antibiotic resistance pattern of actinomycetes isolates among immunocompromised patients in Iran, emerging of new infections

Recent advancements in DNA-based approaches have led to the identification of uncommon and rare bacterial pathogens. In this study, by utilizing a DNA-based approach, a total of 1043 clinical specimens were processed for the identification of actinobacteria targeting the 16S rRNA and gyrB genes. Drug susceptibility testing was also conducted using micro-broth dilution and PCR. Two isolates of Nocardia flavorosea and Rhodococcus erythropolis were reported for the first time in Iran. Also, Nocardiopsis dassonvillei, Streptomyces olivaceus, and Streptomyces griseus were reported for the first time in Asia. Infections caused by Nocardia caishijiensis and Prauserella muralis have also been reported in this study. The first Asian case of pulmonary infection caused by Nocardia ignorata and the first global case of brain abscess caused by Nocardia ninae and Nocardia neocaledoniensis have been reported in this study. Overall 30 isolates belonging to 6 genera (Nocardia, Streptomyces, Rodoccoccus, Nocardiopsis, Rothia, and Prauserella) were detected in 30 patients. All 30 isolates were susceptible to amikacin and linezolid. Three isolates including Nocardia otitidiscaviarum (n = 2) and Nocardia flavorosea (n = 1) were resistant to trimethoprim-sulfamethoxazole which were the first trimethoprim-sulfamethoxazole resistant clinical actinomycetes in Iran. Isolation of rare species of actinomycetes particularly Nocardia spp. requires urgent action before they spread clinically particularly among immunocompromised patients.

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.

Clinical analysis of 11 cases of nocardiosis

Nocardiosis is a rare, life-threatening, opportunistic, and suppurative infection. Its clinical manifestation lacks specificity, which makes early diagnosis difficult. A retrospective analysis of the clinical records of 11 patients with nocardiosis admitted to our hospital from January 2013 to November 2018 was conducted. All patients had at least one underlying disorder, such as an autoimmune disease (6/11), a blood malignancy (2/11), avascular necrosis of the femoral head (1/11), bronchiectasis (1/11), or pneumonia (1/11). The first-line treatment was trimethoprim-sulfamethoxazole (TMP-SMX); one or two additional antibiotics were given according to the drug-sensitive test. The median time from onset to treatment was 3 weeks (ranging from 1 to 9 weeks). The median duration of treatment after diagnosis was 20.5 weeks (ranging from 7 to 47 weeks). Eight patients were discharged and survived, and three patients died. This indicates that early use of TMP-SMX combined with sensitive antibiotics could improve the condition of patients and improve the cure rate (8/11). Clinically, it is necessary to consider the possibility of nocardiosis in patients with long-term use of immunosuppressants and poor response to treatment of common bacterial infections. Early diagnosis, timely treatment, and combination drug therapy are keys to improving the outcomes of patients with nocardiosis.

Rapid identification of Nocardia cyriacigeorgica from a brain abscess patient using MALDI-TOF-MS

Nocardia cyriacigeorgica (N. cyriacigeorgica) is most frequently associated with human infections, including chronic bronchitis, pulmonary disease and brain abscesses. In general, N. cyriacigeorgica causes infections in immunocompromised individuals and has been reported in clinical samples worldwide. However, the isolation and speciation of N. cyriacigeorgica in the routine diagnostic microbiology laboratory are complicated and time consuming. Recent mass spectrometry techniques such as matrix-assisted laser desorption/ionization time-of-flight-mass spectrometry (MALDI-TOF-MS) have been successfully integrated into many routine diagnostic microbiology laboratories, allowing for the rapid, accurate and simple identification and speciation of many different microorganisms, including difficult-to-identify bacterial species. Here, we present a case report of a 65-year-old female patient from the neurology ward of Prince Sultan Military Medical City in Riyadh, Saudi Arabia, who was infected with N. cyriacigeorgica. The bacterium was successfully identified by MALDI-TOF-MS, with species identification subsequently confirmed by sequence analysis of the 16S ribosomal RNA.

Nocardia takedensis: a newly recognized pathogen responsible for skin and soft tissue infections

Nocardia takedensis was first isolated in 2005, from soil in Japan. We report here two cases of lymphangitis in France (2012–2017) caused by N. takedensis both occurring after skin injury while gardening, which enabled its inoculation. The two patients were immunocompromised and successfully treated by an antimicrobial agent active on the isolated strain, trimethoprim-sulfamethoxazole and amoxicillin-clavulanic acid for patient one and patient two, respectively. Our study along with previous ones supports the idea of a newly recognized cutaneous opportunistic pathogen and reinforces the recommendation of using gloves during soil exposure for immunocompromised patients. Lastly, according to data found in the literature, we would recommend trimethoprim-sulfamethoxazole as an efficient empirical antibiotic therapy in case of cutaneous infection caused by N. takedensis.

Nocardia nova Infection of Tibia Tenodesis Implant After Anterior Cruciate Ligament Reconstruction in an Immunocompetent Patient

Infection after anterior cruciate ligament reconstruction and Nocardia infection in immunocompetent hosts are rare events in isolation. This case report highlights the rare combination of these events in a 46-year-old healthy man who acquired a Nocardia nova infection of the tibia tunnel site after an anterior cruciate ligament reconstruction with peroneus allograft. He was successfully treated with tibial tenodesis screw removal, two surgical debridements, and 4 weeks of trimethoprim-sulfamethoxazole and meropenem, followed by 6 months of clarithromycin and original graft retention. This report will review the current antibiotic recommendations and surgical management of this challenging situation. Our case is unique in that the infection was isolated to the distal aspect of the tibial tunnel and did not spread into the entire knee joint, highlighting the importance of early debridement and irrigation in the operative suite when graft site infection is suspected.

Nocardia Bloodstream Infection: A Retrospective Clinical Analysis of Seven Cases in a Single Centre

Objective: Nocardiosis is a rare opportunistic infection caused by the Nocardia species. Nocardia bacteremia is a life-threatening presentation of disseminated nocardiosis that presents diagnostic and therapeutic challenges. We performed this retrospective analysis in a Chinese hospital from 2010 to 2019 to describe the characteristics of this rare bloodstream infection.

Methods: We searched the database of the real-time nosocomial infection surveillance system and identified patients whose blood cultures showed Nocardia bacteria growth. The medical records of these patients were extracted and analyzed by two independent researchers. The data included age, gender, complicating disease, duration from blood drawing to reporting, clinical signs and symptoms, blood routine and C-reactive protein results, radiological examinations, sites of involvement, antibiotic treatments, and outcomes.

Results: Seven patients with Nocardia bacteremia were found. There were four male and three female patients, whose ages ranged from 41 to 75 years. Six (85.7%) patients had predisposing conditions and were administrated corticosteroids for various reasons before the identification of Nocardia infection. The most common symptom was fever (100%). Five patients presented with lung or skin involvement; meanwhile, three patients presented with brain involvement. One patient presented with pelvic and peritoneum involvement, respectively. The most common findings of chest CT imaging were consolidation, followed by nodules and cavitations. Trimethoprim/sulfamethoxazole was prescribed to all patients after the diagnosis of Nocardia bacteremia. Six patients recovered, and one patient ultimately died.

Conclusions: Nocardia bacteremia is a rare bloodstream infection that usually occurs in immunocompromised patients. Clinical manifestations of patients are nonspecific. It often causes multiple organ involvement, and early diagnosis and prompt aggressive interventions are important to improve the outcome of this disease.

Inhibition Activity of Avibactam against Nocardia farcinica β-Lactamase FARIFM10152

Nocardia farcinica, one of the most frequent pathogenic species responsible for nocardiosis, is characterized by frequent brain involvement and resistance to β-lactams mediated by a class A β-lactamase. Kinetic parameters for hydrolysis of various β-lactams by FAR_IFM10152 from strain IFM 10152 were determined by spectrophotometry revealing a high catalytic activity (k _cat/K_m ) for amoxicillin, aztreonam, and nitrocefin. For cephems, k _cat/K_m was lower but remained greater than 10⁴ M^-1 s^-1 A low catalytic activity was observed for meropenem, imipenem, and ceftazidime hydrolysis. FAR_IFM10152 inhibition by avibactam and clavulanate was compared using nitrocefin as a reporter substrate. FAR_IFM10152 was efficaciously inhibited by avibactam with a carbamoylation rate constant (k ₂/K_i ) of (1.7 ± 0.3) × 10⁴ M^-1 s^-1 The 50% effective concentrations (EC₅₀s) of avibactam and clavulanate were 0.060 ± 0.007 μM and 0.28 ± 0.06 μM, respectively. Amoxicillin, cefotaxime, imipenem, and meropenem MICs were measured for ten clinical strains in the presence of avibactam and clavulanate. At 4 μg/ml, avibactam and clavulanate restored amoxicillin susceptibility in all but one of the tested strains but had no effect on the MICs of cefotaxime, imipenem, and meropenem. At 0.4 μg/ml, amoxicillin susceptibility (MIC ≤ 8 μg/ml) was restored for 9 out of 10 strains by avibactam but only for 4 out of 10 strains by clavulanate. Together, these results indicate that avibactam was at least as potent as clavulanate, suggesting that the amoxicillin-avibactam combination could be considered as an option for the rescue treatment of N. farcinica infections if clavulanate cannot be used.

Nocardiosis: A Neglected Disease

Nocardiosis is a neglected tropical disease. It has varied geographical presence and a spectrum of clinical presentations. This review aims to focus on the epidemiology of nocardial infections with a systematic approach to their diagnosis and treatment. Nocardiacauses chronic infections and ailments, and may remain cryptic but progressive in its course. Unless suspected, diagnosis can be easily missed resulting in increased morbidity and mortality. Thorough knowledge of local epidemiology, demography, clinical course and presentation, diagnostic modalities, and antibiotic susceptibility patterns of the prevalent Nocardia species is essential to curb spread of this infection. This is a systematic review in which internet search has been done for citation indices (Embase, PubMed, Ovid, and other individual journals) till March 2020 utilizing the following key words "Nocardia," "taxonomy," "prevalence," "clinical features," "diagnosis," "treatment," and "susceptibility." We selected a total of 87 review articles, case series, and case reports all in English language.

Species Distribution And Antibiotic Susceptibility Of Nocardia Isolates From Yantai, China

Purpose

This study aimed to investigate the species distributions and drug sensitivities among 19 strains of Nocardia isolated from Yantai, China, from 2017 to 2019.

Patients and methods

Definitive species identification was performed by sequencing a fragment of the 16S rRNA gene (1480 bp) and by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS). The susceptibilities of the isolates to 15 commonly-used antibiotics were tested using the microbroth dilution method.

Results

Among the 19 Nocardia isolates, five species were confirmed. Seventeen of the 19 Nocardia spp. strains were identified consistently by the two methods, while two isolates of N. cyriacigeorgica were misidentified as N. otitidiscaviarum by MALDI-TOF MS. N. farcinica was the most common species (8/19), followed by N. cyriacigeorgica (6/19), N. otitidiscaviarum (2/19), N. brasiliensis (2/19), and N. nova (1/19). All isolates were susceptible to trimethoprim-sulfamethoxazole and amikacin, followed by linezolid and tigecycline (94.7% susceptibility rates). The sensitivity and minimum inhibitory concentration patterns for ciprofloxacin, moxifloxacin, clarithromycin, and tobramycin were significantly correlated with the species.

Conclusion

These results regarding the distribution and antibiotic resistance features of Nocardia species further our understanding of the diversity of Nocardia species circulating in Yantai, China, and thus support the use of more accurate empirical treatments.

A multicentre analysis of Nocardia pneumonia in Spain: 2010-2016

OBJECTIVE

To analyse all cases of Nocardia pneumonia occurring between 2010 and 2016 in five Spanish hospitals.

METHODS

This was a retrospective observational analysis of clinical and microbiological data collected from 55 cases of Nocardia pneumonia.

RESULTS

There were one to 20 cases per hospital and six to nine cases per year. Chronic obstructive pulmonary disease, bronchiectasis, and asthma were the main predisposing underlying respiratory conditions. Thirty-four patients were receiving systemic and/or inhaled corticosteroids prior to infection, eight had neoplasia, and six had haematological malignancies. Clinical and radiological findings were common to pneumonia of other infectious aetiologies, except for the frequent presence of nodules and cavitation. Overall, the 1-year mortality was high (38.2%), and mortality was directly related to the pulmonary disease in 15 patients (27.3%). The most frequently identified species were N. cyriacigeorgica (n=21), N. abscessus (n=8), and N. farcinica (n=5). All Nocardia isolates were susceptible to linezolid and all but two were susceptible to amikacin and trimethoprim-sulfamethoxazole.

CONCLUSIONS

Nocardia pneumonia-associated mortality remains high, probably because of the debilitated status of patients in whom this pathogen is able to cause pulmonary infection.

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.

The emergence of rare nocardiosis following allogeneic hematopoietic stem cell transplantation in the era of molecular taxonomy

OBJECTIVE

The purpose of this study was to describe the clinical features of nocardiosis after allogeneic hematopoietic stem cell transplantation (allo-HSCT), focusing on new Nocardia species.

METHODS

We retrospectively reviewed data from patients with nocardiosis after allo-HSCT treated at our hospital and documented cases in the medical literature.

RESULTS

Fifty-seven cases were identified from our institution and the literature review. Although 51 patients (89.5%) responded to initial treatment, 28 (49.1%) patients were switched over to other treatment regimens due to the recurrence of nocardiosis or adverse events of antimicrobials. Nocardiosis-attributed mortality occurred in ten patients (17.5%). Antimicrobial susceptibilities varied among intra- and inter-species except linezolid (LZD). In the present study, five species were newly discovered after 2000, including N. cyriacigeorgica, N. veterana, N. abscessus, N. aobensis, and N. mexicana. All isolates of N. cyriacigeorgica, N. veterana, N. abscessus, and N. aobensis were sensitive to trimethoprim/sulfamethoxazole, amikacin (AMK), imipenem (IPM), and LZD; however, N. mexicana was resistant to AMK and IPM.

CONCLUSION

Newly identified Nocardia species have various antimicrobial susceptibility patterns. Long-term maintenance therapy could be challenging due to the adverse events of antimicrobials, especially in the allo-HSCT setting. Prudent evaluation is crucial for selecting a second-line or further treatment options.

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.

Nocardia infections in solid organ transplantation: Guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation

These updated guidelines from the Infectious Diseases Community of Practice of the American Society of Transplantation review the diagnosis, prevention, and management of Nocardia infections after solid organ transplantation (SOT). Nocardia infections have increased in the last two decades, likely due to improved detection and identification methods and an expanding immunocompromised population. The risk of developing nocardiosis after transplantation varies with the type of organ transplanted and the immunosuppression regimen used. Nocardia infection most commonly involves the lung. Disseminated infection can occur, with spread to the bloodstream, skin, or central nervous system. Early recognition of the infection and initial appropriate treatment is important to achieve good outcomes. Species identification and antimicrobial susceptibility testing are strongly recommended, as inter- and intraspecies susceptibility patterns can vary. Sulfonamide is the first-line treatment of Nocardia infections, and combination therapy with at least two antimicrobial agents should be used initially for disseminated or severe nocardiosis. Trimethoprim-sulfamethoxazole (TMP-SMX) prophylaxis may be helpful in preventing Nocardia infection after SOT.

[Cerebral and pulmonary nocardiosis to Nocardia abscessus in an immunocompetent Algerian patient]

Nocardial brain abscess is often occurring in immunocompromised patients. It is uncommon in immunocompetent individuals. Here, the authors describe a case of cerebral and pulmonary nocardiosis mimicking a metastatic tumor in an apparently health 40-year-old Algerian male. The patient presented multiple brain abscess revealed by inaugural epileptic seizure. He was afebrile and presented with left hemiparesis. Staging imaging showed a nodular lung lesion in the apical segment of the right lower lobe. The patient underwent double craniotomy for resection of the lesion. Culture of the resected specimen isolated Nocardia abscessus. The patient was initially started on intravenous trimethoprim-sulfamethoxazole and intravenous amikacine. He was switched to oral trimethoprim-sulfamethoxazole. He finished seven months of antibiotic therapy with a good clinical response. Imaging revealed reduction in the brain abscess and a complete resolution of the lung lesion. Cotrimoxazole was stopped after twelve months of therapy. After two years, the health status of our patient improves day after day. He is however regularly under medical supervision for control exams.

Clinical features, identification, antimicrobial resistance patterns of Nocardia species in China: 2009-2017

Nocardia spp. is a pathogen responsible for a variety of clinical infections, ranging from skin and soft tissue infections, to the respiratory tract and central nervous system infections. Its epidemiological characteristics, including species distribution, clinical features, and antimicrobial susceptibility profiles, should be under surveillance for the prevention and treatment of nocardiosis. In the present study, over a 9-year period (from 2009 to 2017), 53 non-repetitive Nocardia isolates were collected from 8 tertiary general hospitals of 7 cities in China. These isolates were identified to species level by multilocus sequence analysis(MLSA). The clinical data were also reviewed. The susceptibilities to 10 commonly-used antibiotics for Nocardia were determined by E-test stripes, and the resistance rates, MIC₅₀ and MIC₉₀ to each antibiotic by different species were analyzed. Of 53 Nocardia isolates, N. farcinica was the most common species (24.5%, 13/53), followed by N. cyriacigeorgica (20.8%, 11/53), N. terpenica (15.1%, 8/53), N. abscessus (9.43%, 5/53), N. otitidiscaviarum (7.55%, 4/53), respectively. Furthermore, 31 Nocardia (58.5%) isolates were recovered from lower respiratory tract (sputum and BALF), 15 (28.3%) from superficial Infection, 3 (5.7%) from pleural effusion, 2 (3.8%) from CSF, and 1 from bone marrow and 1 from synovial fluid, respectively. The antibiotic resistance profiles varied between different Nocardia species. All Nocardia isolates were susceptible to linezolid, followed by imipenem and amikacin (both 92.5% susceptibility rate). N. terpenica, rarely documented elsewhere, showed a different antimicrobial susceptibility profile. In summary, herein, the clinical and antibiotic resistance features of Nocardia species reported would be helpful for understanding the diversity of Nocardia species circulating in China and for decision making in the context of empiric therapy.

An unusual case of Nocardia cyriacigeorgica presenting with spinal abscesses in a renal transplant recipient and a review of the literature

Nocardia species represent a well-recognized yet uncommon cause of opportunistic infections in humans. It most frequently presents as a pulmonary infection with or without central nervous system involvement. It is a very rare cause of spinal abscesses, with only 26 cases reported in the literature. Here we report a 49-year-old man with a history of renal transplantation who presented with low back pain and was diagnosed with epidural and paraspinal abscesses due to Nocardia cyriacigeorgica that was successfully treated with antimicrobial therapy alone. In addition to the case reported here, we also conducted a systematic review of the existing literature regarding spinal abscesses due to Nocardia species and examined the success of the various treatments utilized.

Pulmonary infection caused by Nocardia cyriacigeorgica in a patient with allergic bronchopulmonary aspergillosis: A case report

RATIONALE

Nocardia species is known as conditional pathogenic bacteria. Among Nocardia species, pulmonary infection caused by Nocardia cyriacigeorgica associated with Aspergillus fumigatus complex lung disease is rarely reported.

PATIENT CONCERNS

A 55-year-old female with a history of productive cough with recurrent expectoration for 20 years presented with increasing cough for 12 months. The patient presented complaining of respiratory symptoms including increasing cough with yellow phlegm, poor appetite, and generalized fatigue for a week prior to admission.

DIAGNOSES

Nocardia cyriacigeorgica pneumonia was identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing.

INTERVENTIONS

Combined treatments (trimethoprim-sulfamethoxazole and meropenem) were administered after identification of N cyriacigeorgica.

OUTCOMES

The respiratory symptoms of the patient had improved both clinically and radiologically after 4 weeks of antibacterial therapy.

LESSONS

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

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.

Antimicrobial susceptibility and clinical characteristics of Nocardia isolates from a tertiary care centre diagnostic laboratory in Pakistan

OBJECTIVES

Nocardiosis is an opportunistic infection that can present as cutaneous, pulmonary and/or disseminated disease depending on the host immunity. Treatment choices include trimethoprim/sulfamethoxazole (co-trimoxazole; SXT) and imipenem along with some other antibiotics. The Clinical and Laboratory Standards Institute (CLSI) recommends the broth microdilution (BMD) method to determine antimicrobial susceptibility, however there is a lack of susceptibility data using this method in Pakistan. Therefore, this study was undertaken to outline the susceptibility profile of Nocardia isolates in Pakistan.

METHODS

From November 2014 to June 2016, 52 consecutive isolates of Nocardia obtained from clinical specimens cultured at the clinical microbiology laboratory of Aga Khan University Hospital (Karachi, Pakistan) were tested for susceptibility to recommended antibiotics using the CLSI-recommended BMD method. The frequency and percentage of susceptibility and resistance of Nocardia to antimicrobials recommended by CLSI were calculated. The susceptibility profiles of pulmonary and extrapulmonary specimens were compared by χ² test.

RESULTS

Of the 52 isolates, 47 (90.4%) were susceptible to SXT, 20 (38.5%) to imipenem, 49 (94.2%) to amikacin and 52 (100%) to linezolid. No significant differences were found when susceptibilities were compared between pulmonary and extrapulmonary isolates.

CONCLUSION

This study highlights the importance of using the gold-standard BMD method for susceptibility testing of Nocardia isolates. Larger studies are needed in the region to establish susceptibility profiles of Nocardia spp. using the BMD method in order to monitor resistance trends and to inform empirical therapy choices.

Rare case of osteomyelitis of tibial shaft caused by Nocardia cyriacigeorgica

Nocardiosis is a rare infection caused by the aerobic actinomycete of the Nocardia genus. In most cases, nocardiosis manifests as a lung infection or a bone lesion. Due to the nonspecific and mild clinical manifestations of nocardiosis, the establishment of definite diagnosis can be difficult. When antibiotic therapy is incorrectly targeted, only the symptoms of the disease are suppressed. The mainstay in the treatment of Nocardia osteomyelitis has so far been the combined surgical debridement with long-term, initially intravenous, antibiotic administration. We present the successful conservative treatment of a nocardiosis osteomyelitis of the tibia caused by the Nocardia cyriacigeorgica species in an 81-year-old female patient that manifested itself as a secondary affection on top of a primary nocardiosis infection of the lung. From microbiological examination, N. cyriacigeorgica was discovered; the identification was made using matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) with an identification score of 1.9. The sensitivity was evaluated using E test. Sensitivity to trimethoprim/sulfamethoxazole, amikacin, imipenem, and linezolid was demonstrated. The bacteria were shown to be resistant to ciprofloxacin. For treatment, trimethoprim/sulfamethoxazole was used due to the value of minimum inhibitory concentration, which was 0.25 mg/L. The initial dose of 960 mg of trimethoprim/sulfamethoxazole every 8 h was reduced to 960 mg every 12 h after 3 months. The total duration of treatment was 7.5 months. Under the established treatment, the bone and lung lesions healed. Nocardiosis of the long bone is considered a rare disease and its precise diagnosis has not yet been standardized. We used the MALDI-TOF MS method for the identification of the causal organism which is a fast and reliable method according to current world literature even when compared with the rRNA genetic sequencing reference method. Our case study presents a rare case of osteomyelitis of tibial shaft caused by N. cyriacigeorgica and its successful conservative treatment.

Fulminant Nocardiosis Due to a Multidrug-Resistant Isolate in a 12-Year-Old Immunocompetent Child

Nocardiosis is a rare cause of infection that usually affects immunocompromised adult patients and might not be recognized by pediatricians. We report a fatal case of disseminated nocardiosis in a previously healthy child initially admitted for an abdominal mass with suspicion of a renal malignant tumor. The patient, originating from Mali without any medical history, displayed abdominal pain with progressive altered general status. Laboratory and imaging findings revealed lymphocytic meningitis and disseminated abscesses in the brain and the cerebellum and a large number of cystic lesions of the kidney. Despite being administered wide-spectrum antibiotics and antituberculous and antifungal therapies with an external ventricular drainage for intracranial hypertension, the patient died 6 days after his admission. Nocardia spp was cultured from a renal biopsy and the cerebrospinal fluid. Species identification and antibiotic susceptibility were obtained later, revealing a multidrug-resistant isolate of the Nocardia elegans/aobensis/africana complex. This case reveals the difficulties of diagnosing nocardiosis, in particular in children not known to be immunocompromised, because we face multiple differential diagnoses and the importance of treating nocardiosis appropriately because of intrinsic resistance issues.

Increasing Nocardia Incidence Associated with Bronchiectasis at a Tertiary Care Center

RATIONALE

Nocardia is a genus of pathogens that most commonly afflict immunocompromised hosts but may be an emerging infection among persons with bronchiectasis.

OBJECTIVES

To examine the epidemiology and clinical presentation of adult patients with Nocardia and bronchiectasis relative to other patient groups.

METHODS

We examined a retrospectively assembled cohort of adults at Duke University Hospital in Durham, North Carolina with at least one positive culture from a bodily fluid or tissue specimen for Nocardia between January 1996 and December 2013. Denominator data for key populations (e.g., bronchiectasis, transplant) were obtained using International Classification of Diseases, Ninth Revision codes. In addition, we performed a case-control analysis to examine the relationship between inhaled corticosteroid use and Nocardia lung infection among otherwise immunocompetent patients with bronchiectasis.

MEASUREMENTS AND MAIN RESULTS

We identified 183 patients with one or more cultures positive for Nocardia: 44 from 1996 to 2001, 64 from 2002 to 2007, and 75 from 2008 to 2013. Immune compromise was common (56%), particularly solid organ or hematopoietic cell transplant (30%). Infection usually was confined to the lungs (62%), followed by skin (10%), other sites (6%), brain (2%), and multiple sites (17%). Non-cystic fibrosis bronchiectasis was common among both immunocompetent (38%) and immunocompromised (10%) patients. Nocardia incidence in patients with bronchiectasis increased significantly over time, but there was no significant change in Nocardia incidence in hematopoietic cell or solid organ transplant recipients (our largest immunocompromised population). Among patients with bronchiectasis, Nocardia was positively but nonsignificantly associated with use of inhaled corticosteroids (odds ratio, 1.8; 95% confidence interval, 0.7-4.4).

CONCLUSIONS

The increasing incidence of Nocardia infections at our medical center appears to be driven by increased incidence in patients with bronchiectasis rather than increases in immunocompromised populations. It is unclear whether increased environmental exposures, microbiologic surveillance, or other factors account for the increased incidence of Nocardia in our patients with bronchiectasis.

Epidemiology and susceptibility to antimicrobial agents of the main Nocardia species in Spain

Objectives

The aims of this study were to explore the clinical distribution, by species, of the genus Nocardia and to assess the antimicrobial susceptibilities of the 10 most prevalent species identified in Spain.

Methods

Over a 10 year period (2005-14), 1119 Nocardia strains were molecularly identified and subjected to the Etest. The distribution and resistance trends over the sub-periods 2005-09 and 2010-14 were also examined.

Results

Of the strains examined, 82.9% belonged to the following species: Nocardia cyriacigeorgica (25.3%), Nocardia nova (15.0%), Nocardia abscessus (12.7%), Nocardia farcinica (11.4%), Nocardia carnea (4.3%), Nocardia brasiliensis (3.5%), Nocardia otitidiscaviarum (3.1%), Nocardia flavorosea (2.6%), Nocardia rhamnosiphila (2.6%) and Nocardia transvalensis (2.4%). Their prevalence values were similar during 2005-09 and 2010-14, except for those of N. abscessus , N. farcinica and N. transvalensis , which fell significantly in the second sub-period ( P ≤  0.05). The major location of isolation was the respiratory tract (∼86%). Half (13/27) of all strains from the CNS were N. farcinica . Significant differences in MIC results were recorded for some species between the two sub-periods. According to the CLSI's breakpoints, low resistance rates (≤15%) were recorded for seven species with respect to cefotaxime, imipenem and tobramycin; five species showed similar rates with respect to trimethoprim/sulfamethoxazole. Linezolid and amikacin were the most frequently active agents.

Conclusion

The accurate identification of the infecting species and the determination of its susceptibility to antimicrobial agents, given the large number of strains with atypical patterns, are crucial if patients with nocardiosis are to be successfully treated.

Identification and antimicrobial susceptibility of clinical Nocardia species in a tertiary hospital in China

OBJECTIVES

There is a lack of information on the activities of antimicrobial agents against Nocardia clinical isolates of specific species in China. The aim of this study was to determine the antibiotic susceptibility of 28 clinical isolates of Nocardia spp. isolated from Beijing Chao-Yang Hospital (Beijing, China).

METHODS

Molecular diagnosis of Nocardia spp. was performed using partial 16S rRNA and rpoB gene sequences. Antimicrobial susceptibility testing was performed by broth microdilution according to Clinical and Laboratory Standards Institute (CLSI) recommendations.

RESULTS

The species distribution was as follows: Nocardia cyriacigeorgica (n=13); Nocardia farcinica (n=6); Nocardia beijingensis (n=3); Nocardia abscessus (n=2); Nocardia wallacei (n=2); Nocardia otitidiscaviarum (n=1); and Nocardia nova (n=1). The susceptibility rates to trimethoprim/sulfamethoxazole (SXT), linezolid, amikacin, imipenem, tobramycin, ceftriaxone and cefotaxime were 100.0%, 100.0%, 92.9%, 75.0%, 67.9%, 67.9% and 64.3%, respectively, whilst the resistance rate both to ciprofloxacin and clarithromycin was 71.4%.

CONCLUSIONS

N. cyriacigeorgica was the most frequently isolated Nocardia spp. All clinical isolates showed low susceptibility to ciprofloxacin and clarithromycin and complete susceptibility both to SXT and linezolid, which can be considered the primary choice for the treatment of Nocardia infections in China.

Isolation, biochemical and molecular identification of Nocardia species among TB suspects in northeastern, Tanzania; a forgotten or neglected threat?

BACKGROUND

Pulmonary nocardiosis mimic pulmonary tuberculosis in most clinical and radiological manifestations. In Tanzania, where tuberculosis is one of the major public health threat clinical impact of nocardiosis as the cause of the human disease remains unknown. The objective of the present study was to isolate and identify Nocardia isolates recovered from TB suspects in Northeastern, Tanzania by using biochemical and molecular methods.

METHODS

The study involved 744 sputum samples collected from 372 TB suspects from four periphery diagnostic centers in Northeastern, Tanzania. Twenty patients were diagnosed as having presumptively Nocardia infections based on microscopic, cultural characteristics and biomèrieux ID 32C Yeast Identification system and confirmed using 16S rRNA and hsp65 gene specific primers for Nocardia species and sequencing.

RESULTS

Biochemically, the majority of the isolates were N. asteroides (n = 8/20, 40%), N. brasiliensis (n = 4/20, 20%), N. farcinica (n = 3/20, 15%), N. nova (n = 1/20, 5%). Other aerobic actinomycetales included Streptomyces cyanescens (n = 2/20, 10%), Streptomyces griseus, Actinomadura madurae each (n = 1/20, 5%). Results of 16S rRNA and hsp65 sequencing were concordant in 15/17 (88. 2%) isolates and discordant in 2/17 (11.8%) isolates. Majority of the isolates belonged to N. cyriacigeorgica and N. farcinica, four (23.5%) each.

CONCLUSIONS

Our findings suggest that Nocardia species may be an important cause of pulmonary nocardiosis that is underdiagnosed or ignored. This underscores needs to consider pulmonary nocardiosis as a differential diagnosis when there is a failure of anti-TB therapy and as a possible cause of human infections.