Granulomatous Thyroiditis: A Case Report and Literature Review

BACKGROUND

Granulomatous disease in the thyroid gland has been linked to viral, bacterial and autoimmune etiologies. The most common granulomatous disease of the thyroid is subacute granulomatous thyroiditis, which is presumed to have a viral or post-viral inflammatory cause. Bacterial etiologies include tuberculosis, actinomycosis, and nocardiosis, but are extremely rare. Disseminated actinomycosis and nocardiosis more commonly affect organ-transplant patients with the highest susceptibility within the first year after transplant surgery.

CASE

A 45-year-old African American male, who received his third kidney transplant for renal failure secondary to Alport Syndrome, presented with numerous subcutaneous nodules and diffuse muscle pain in the neck. Further workup revealed bilateral nodularity of the thyroid. Fine needle aspiration of these nodules demonstrated suppurative granulomatous thyroiditis. Subsequent right thyroid lobectomy showed granulomatous thyroiditis with filamentous micro-organisms, morphologically resembling Nocardia or Actinomyces.

CONCLUSION

Disseminated granulomatous disease presenting in the thyroid is very rare, and typically afflicts immune-compromised patients. The overall clinical, cytologic and histologic picture of this patient strongly points to an infectious etiology, likely Nocardia, in the setting of recent organ transplantation within the last year.

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.

Identification of Nocardia, Streptomyces, and Tsukamurella using MALDI-TOF MS with the Bruker Biotyper

Nocardia species are the most commonly isolated aerobic actinomycetes from human clinical specimens. Our objective was to assess the identification of clinically relevant actinomycetes using the Bruker Biotyper MALDI-TOF system, including comparison of extraction methods, Biotyper library versions, score cutoffs, and media. Banked Streptomyces (n=10), Tsukamurella (n=2), and Nocardia isolates (n=60) were cultured and extracted using three methods: mycobacterial extraction, ethanol formic acid extraction, or direct on-target extraction. Following MALDI-TOF analysis, spectra were analyzed using versions 5 and 6 of the BDAL Biotyper library. Optimal species-level identifications for Nocardia were achieved using BDAL v6 at a score cutoff of ≥1.8 after direct extraction (49/60, 82%). Overall, the Biotyper platform with BDAL v6 accurately identified 12/16 species of Nocardia, demonstrating the utility of MALDI-TOF for identification of clinically relevant actinomycetes without the need for supplementation of the database.

Nocardia beijingensis brain abscesses in an HIV-infected individual

We describe a case of a 50-year-old Hispanic man diagnosed with HIV/AIDS who presented with a generalized tonic clonic seizure and ring enhancing cerebral lesions on imaging. He was initially treated for CNS toxoplasmosis but presented to the hospital with another tonic clonic seizure despite prescribed therapy. Brain biopsy was performed which revealed Nocardia beijingensis. He was treated with intravenous meropenem and trimethoprim/sulfamethoxazole for six weeks followed by long term oral trimethoprim/sulfamethoxazole with radiographic and clinical improvement.

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.

Outcome and Treatment of Nocardiosis After Solid Organ Transplantation: New Insights From a European Study

BACKGROUND

Solid organ transplant (SOT) recipients are at risk of nocardiosis, a rare opportunistic bacterial infection, but prognosis and outcome of these patients are poorly defined. Our objectives were to identify factors associated with 1-year mortality after nocardiosis and describe the outcome of patients receiving short-course antibiotics (≤120 days).

METHODS

We analyzed data from a multicenter European case-control study that included 117 SOT recipients with nocardiosis diagnosed between 2000 and 2014. Factors associated with 1-year all-cause mortality were identified using multivariable conditional logistic regression.

RESULTS

One-year mortality was 10-fold higher in patients with nocardiosis (16.2%, 19/117) than in control transplant recipients (1.3%, 3/233, P < .001). A history of tumor (odds ratio [OR], 1.4; 95% confidence interval [CI], 1.1-1.8), invasive fungal infection (OR, 1.3; 95% CI, 1.1-1.5), and donor age (OR, 1.0046; 95% CI, 1.0007-1.0083) were independently associated with 1-year mortality. Acute rejection in the year before nocardiosis was associated with improved survival (OR, 0.85; 95% CI, 0.73-0.98). Seventeen patients received short-course antibiotics (median duration 56 [24-120] days) with a 1-year success rate (cured and surviving) of 88% and a 5.9% risk of relapse (median follow-up 49 [6-136] months).

CONCLUSIONS

One-year mortality was 10-fold higher in SOT patients with nocardiosis than in those without. Four factors, largely reflecting general medical condition rather than severity and/or management of nocardiosis, were independently associated with 1-year mortality. Patients who received short-course antibiotic treatment had good outcomes, suggesting that this may be a strategy for further study.

Molecular identification of Nocardia species using the sodA gene: Identificación molecular de especies de Nocardia utilizando el gen sodA

Currently for bacterial identification and classification the rrs gene encoding 16S rRNA is used as a reference method for the analysis of strains of the genus Nocardia. However, it does not have enough polymorphism to differentiate them at the species level. This fact makes it necessary to search for molecular targets that can provide better identification. The sodA gene (encoding the enzyme superoxide dismutase) has had good results in identifying species of other Actinomycetes. In this study the sodA gene is proposed for the identification and differentiation at the species level of the genus Nocardia. We used 41 type species of various collections; a 386 bp fragment of the sodA gene was amplified and sequenced, and a phylogenetic analysis was performed comparing the genes rrs (1171 bp), hsp65 (401 bp), secA1 (494 bp), gyrB (1195 bp) and rpoB (401 bp). The sequences were aligned using the Clustal X program. Evolutionary trees according to the neighbour-joining method were created with the programs Phylo_win and MEGA 6. The specific variability of the sodA genus of the genus Nocardia was analysed. A high phylogenetic resolution, significant genetic variability, and specificity and reliability were observed for the differentiation of the isolates at the species level. The polymorphism observed in the sodA gene sequence contains variable regions that allow the discrimination of closely related Nocardia species. The clear specificity, despite its small size, proves to be of great advantage for use in taxonomic studies and clinical diagnosis of the genus Nocardia.

Adjuvant interferon-gamma immunotherapy in a patient with progressive cerebral Nocardia abscesses

Despite advances in medical care, mortality due to cerebral Nocardia abscesses remains unacceptably high. The case of a typical immunocompromised patient, who deteriorated clinically despite optimal antimicrobial treatment, is reported here. Adjuvant immunotherapy with interferon-gamma resulted in partial restoration of the immune response and a corresponding clinical and radiographic recovery.

Isolation and Structure Identification of Novel Brominated Diketopiperazines from Nocardia ignorata-A Lichen-Associated Actinobacterium

Actinobacteria are well known for their potential in biotechnology and their production of metabolites of interest. Lichens are a promising source of new bacterial strains, especially Actinobacteria, which afford a broad chemical diversity. In this context, the culture medium of the actinobacterium Nocardia ignorata, isolated from the terrestrial lichen Collema auriforme, was studied. The strain was cultivated in a BioFlo 115 bioreactor, and the culture medium was extracted using an XAD7HP resin. Five known diketopiperazines: cyclo (l-Pro-l-OMet) (1), cyclo (l-Pro-l-Tyr) (2), cyclo (d-Pro-l-Tyr) (3), cyclo (l-Pro-l-Val) (4), cyclo (l-Pro-l-Leu) (5), and one auxin derivative: indole-carboxaldehyde (8) were isolated, along with two new brominated diketopiperazines: cyclo (d-Pro-l-Br-Tyr) (6) and cyclo (l-Pro-l-Br-Tyr) (7). Structure elucidation was performed using HRMS and 1D and 2D NMR analysis, and the synthesis of compounds 6 and 7 was carried out in order to confirm their structure.

Characterization and functional expression of a rubber degradation gene of a Nocardia degrader from a rubber-processing factory

A rubber-degrading bacterial consortium named H2DA was obtained from an enrichment culture with natural rubber latex and rubber-processing factory waste in Vietnam. Gel permeation chromatography analysis revealed that only the strain NVL3 degraded synthetic poly(cis-1,4-isoprene) into low-molecular-weight intermediates among the three strains found in the H2DA. The 16S-rRNA gene sequence of NVL3 showed the highest identity with that of Nocardia farcinica DSM 43665^T. NVL3 accumulated aldehyde intermediates from synthetic poly(cis-1,4-isoprene) on a rubber-overlay plate as indicated by Schiff's staining. NVL3 also degraded deproteinized natural rubber into low-molecular-weight aldehyde intermediates. A latex-clearing protein (lcp) gene ortholog was identified within the genome sequence of NVL3, and it showed a moderate amino-acid identity (54-75%) with the lcp genes from previously reported rubber degraders. The heterologous expression of the NVL3 lcp in Escherichia coli BL21(DE3) allowed us to purify the 46.8-kDa His-tagged lcp gene product (His-Lcp). His-Lcp degraded synthetic poly(cis-1,4-isoprene) and accumulated aldehyde intermediates from deproteinized natural rubber suggesting the functional expression of the lcp gene from a Nocardia degrader in E. coli. Quantitative reverse transcription PCR analysis indicated the strong transcriptional induction of the lcp gene in NVL3 in the presence of synthetic poly(cis-1,4-isoprene). These results suggest the involvement of the lcp gene in rubber degradation in NVL3.

Enhanced production of nargenicin A1 and creation of a novel derivative using a synthetic biology platform

Nargenicin A1, an antibacterial produced by Nocardia sp. CS682 (KCTC 11297BP), demonstrates effective activity against various Gram-positive bacteria. Hence, we attempted to enhance nargenicin A1 production by utilizing the cumulative effect of synthetic biology, metabolic engineering and statistical media optimization strategies. To facilitate the modular assembly of multiple genes for genetic engineering in Nocardia sp. CS682, we constructed a set of multi-monocistronic vectors, pNV18L1 and pNV18L2 containing hybrid promoter (derived from ermE* and promoter region of neo ^r ), ribosome binding sites (RBS), and restriction sites for cloning, so that each cloned gene was under its own promoter and RBS. The multi-monocistronic vector, pNV18L2 containing transcriptional terminator showed better efficiency in reporter gene assay. Thus, multiple genes involved in the biogenesis of pyrrole moiety (ngnN2, ngnN3, ngnN4, and ngnN5 from Nocardia sp. CS682), glucose utilization (glf and glk from Zymomonas mobilis), and malonyl-CoA synthesis (accA2 and accBE from Streptomyces coelicolor A3 (2)), were cloned in pNV18L2. Further statistical optimization of specific precursors (proline and glucose) and their feeding time led to ~84.9 mg/L nargenicin from Nocardia sp. GAP, which is ~24-fold higher than Nocardia sp. CS682 (without feeding). Furthermore, pikC from Streptomyces venezuelae was expressed to generate Nocardia sp. PikC. Nargenicin A1 acid was characterized as novel derivative of nargenicin A1 produced from Nocardia sp. PikC by mass spectrometry (MS) and nuclear magnetic resonance (NMR) analyses. We also performed comparative analysis of the anticancer and antibacterial activities of nargenicin A1 and nargenicin A1 acid, which showed a reduction in antibacterial potential for nargenicin A1 acid. Thus, the development of an efficient synthetic biological platform provided new avenues for enhancing or structurally diversifying nargenicin A1 by means of pathway designing and engineering.

First Case of Actinomycetoma in France Due to a Novel Nocardia Species, Nocardia boironii sp. nov

Bacterial mycetoma is an endemic infection in areas with tropical and subtropical climates. Thus, its presence in temperate climate areas remains rare. We report here the first case of autochthonous actinomycetoma in continental France originating from a Nocardia species other than N. brasiliensis, namely, Nocardia boironii. Considering the history of the patient, the infection source of strain OFN 14.177^T may be from frequent contact with the soil over many years because of his gardening activities. The discovery of a French autochthonous Nocardia species responsible for actinomycetoma reveals the importance of considering the possibility of having autochthonous infections of this type in nontropical countries, not only imported cases from tropical countries. However, further studies are needed to elucidate the real incidence of this new species.

Bacterial mycetoma is a neglected disease mainly observed in tropical area countries and typically associated with rural conditions, making its presence in developed countries of temperate climate areas rare. However, we report the first case of an autochthonous mycetoma case in continental France that originated from a new Nocardia species. A Gram-positive filamentous bacterium (OFN 14.177^T) was isolated from a pus sample from the mycetoma of a male French patient 92 years old suffering from chronic lymphocytic leukemia. The isolate was analyzed by a polyphasic taxonomic approach by coupling morphological, biochemical, physiological, and chemotaxonomic aspects to genomic and phylogenetic analyses. Multilocus sequence analysis (MLSA) using four housekeeping genes (16S rRNA gene, secA1, hsp65, and sod) combined with phylogenetic analysis revealed that the strain OFN 14.177^T is phylogenetically closer not only to Nocardia altamirensis but also to all other species comprising the Nocardia brasiliensis clade (i.e., N. brasiliensis, N. altamirensis, N. vulneris, N. iowensis, and N. tenerifensis), some of which present cutaneous tropism. The G+C content of isolate OFN 14.177^T was 68.2 mol%. DNA-DNA hybridization analyses demonstrated 38.25% relative reassociation with N. altamirensis. The strain OFN 14.177^T is different from the closest species at genetic and phenotypical levels, and the data obtained indicate that it should be recognized as a new species, for which the name of Nocardia boironii sp. nov. is proposed. The type strain is OFN 14.177^T (= EML 1451 = DSM 101696).

IMPORTANCE Bacterial mycetoma is an endemic infection in areas with tropical and subtropical climates. Thus, its presence in temperate climate areas remains rare. We report here the first case of autochthonous actinomycetoma in continental France originating from a Nocardia species other than N. brasiliensis, namely, Nocardia boironii. Considering the history of the patient, the infection source of strain OFN 14.177^T may be from frequent contact with the soil over many years because of his gardening activities. The discovery of a French autochthonous Nocardia species responsible for actinomycetoma reveals the importance of considering the possibility of having autochthonous infections of this type in nontropical countries, not only imported cases from tropical countries. However, further studies are needed to elucidate the real incidence of this new species.

Different faces of Nocardia infection in renal transplant recipients

AIM

Nocardia infections are an uncommon but important cause of morbidity and mortality in renal transplant recipients. The present study was carried out to determine the spectrum of Nocardia infections in a renal transplant centre in Australia.

METHODS

A retrospective chart analysis of all renal transplants performed from 2008 to 2014 was conducted to identify cases of culture proven Nocardia infection. The clinical course for each patient with nocardiosis was examined.

RESULTS

Four of the 543 renal transplants patients developed Nocardia infection within 2 to 13 months post-transplant. All patients were judged at high immunological risk of rejection pre-transplant and had received multiple sessions of plasmaphoeresis and intravenous immunoglobulin before the onset of the infection. Two patients presented with pulmonary nocardiosis and two with cerebral abscesses. One case of pulmonary nocardiosis was complicated by pulmonary aspergillosis and the other by cytomegalovirus pneumonia. All four patients improved with combination antibiotic therapy guided by drug susceptibility testing. At the time of Nocardia infection all four patients were receiving primary prophylaxis with trimethoprim/sulphamethoxazole (TMP/SMX) 160/800 mg, twice weekly.

CONCLUSION

Plasmaphoeresis may be risk factor for Nocardia infection and need further study. Nocardia infection may coexist with other opportunistic infections. Identification of the Nocardia species and drug susceptibility testing is essential in guiding the effective management of patients with Nocardia. Intermittent TMP-SMX (one double strength tablet, twice a week) appears insufficient to prevent Nocardia infection in renal transplant recipients.

Routine identification of Nocardia species by MALDI-TOF mass spectrometry

We here show adequate species identification for bacterial isolates of the genus Nocardia spp. through VITEK mass spectrometry. Application of a specific sample preparation method in combination with a robust matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) database leads to 94% accurate identification to the species level on a set of 164 isolates. The possibility to identify Nocardia spp. using MALDI-TOF MS will be available in the next release of VITEK MS update (IVD Version 3.0).

Nocardiosis in the Tropical Northern Territory of Australia, 1997-2014

BACKGROUND

Nocardia is an opportunistic pathogen that can cause life-threatening disease. We aimed to characterize the epidemiological, microbiological, and clinical features of nocardiosis in the tropical north of Australia.

METHODS

We conducted a retrospective cohort study of nocardiosis diagnosed between 1997 and 2014. Population-based incidences were calculated using district population data.

RESULTS

Clinically significant nocardiosis was identified in 61 patients. The unadjusted population-based annual incidence of nocardiosis was 2.02 (95% confidence interval [CI], 1.55-2.60) per 100000 people and was 1.7 (95% CI, .96-2.90) fold higher in Indigenous compared with non-Indigenous persons (P = .027). Of 61 patients, 47 (77%) had chronic lung disease, diabetes, and/or hazardous alcohol consumption; 22 (36%) were immunocompromised; and 8 (13%) had no identified comorbidities. Disease presentations included pulmonary (69%; 42 of 61), cutaneous (13%; 8 of 61), and disseminated nocardiosis (15%; 9 of 61). The most commonly identified species were Nocardia asteroides and Nocardia cyriacigeorgica (each 11%). Linezolid was the only antimicrobial to which isolates were universally susceptible; 89% (48 of 54), 60% (32 of 53), and 48% (26 of 54) of isolates were susceptible to trimethoprim-sulfamethoxazole, ceftriaxone, and imipenem, respectively. Eighteen patients (30%) required intensive care unit (ICU) admission, and 1-year mortality was 31%.

CONCLUSIONS

The incidence of nocardiosis in tropical Australia is amongst the highest reported globally. Nocardiosis occurs in both immunocompromised and immunocompetent hosts, and it is associated with high rates of ICU admission, 1-year mortality, and resistance to commonly recommended antimicrobials. Diagnosis should be considered in patients with consistent clinical features, particularly if they are Indigenous or have chronic lung disease.

Nocardia arthritidis as a cause of disseminated nocardiosis in a patient with chronic lymphocytic leukemia

A case of disseminated nocardiosis caused by Nocardia arthritidis in an immunocompromised patient with a history of chronic lymphocytic leukemia and rheumatoid arthritis is presented. This report highlights the use for multilocus sequence typing (MLST) in addition to single gene molecular sequencing to identify rare Nocardia species.

[Nocardiosis: A retrospective case series of 19 patients]

INTRODUCTION

Nocardiosis are uncommon. The diagnosis may be difficult, with significant morbidity and mortality, often occurring on frail patients. Few data are available in France.

METHODS

A retrospective single center study was conducted from 2002 to 2014 and included all patients with at least one positive microbiological sample for Nocardia with a follow-up in our hospital.

RESULTS

Nineteen patients, including 15 men, were included with a mean age of 58 years (25-85). Seventeen had a risk factor (lung diseases [13], corticosteroids [12], solid neoplasia [2], HIV infection [2], diabetes mellitus [3], kidney transplant [2], lymphopenia [1]). Infections' locations were: pulmonary (12), brain (3), skin (2), lymph node (1) and corneal (1). The slow growth leads to a median of 35 days for a positive result (3-95). Nine species were identified. Fifteen patients (79%) received one or more lines of antibiotics including: cotrimoxazole (9), amoxicillin (7) cefotaxime/ceftriaxone (7) imipenem (3), or amikacin (3). The average duration of antibiotic therapy was 207 days. Four patients did not receive antibiotics due to a late result or a bacterial co-infection masking nocardiosis. Five patients died (26%) including 2 with cerebral nocardiosis. Six patients were cured, 4 suffered a relapse, 4 had an unknown evolution, and 1 was still treated.

CONCLUSION

Our study shows that nocardiosis is a disease difficult to treat. A better understanding of this type of infection is necessary.

Enhanced production of nargenicin A1 and creation of a novel derivative using a synthetic biology platform

Nargenicin A1, an antibacterial produced by Nocardia sp. CS682 (KCTC 11297BP), demonstrates effective activity against various Gram-positive bacteria. Hence, we attempted to enhance nargenicin A1 production by utilizing the cumulative effect of synthetic biology, metabolic engineering and statistical media optimization strategies. To facilitate the modular assembly of multiple genes for genetic engineering in Nocardia sp. CS682, we constructed a set of multi-monocistronic vectors, pNV18L1 and pNV18L2 containing hybrid promoter (derived from ermE* and promoter region of neo ^r ), ribosome binding sites (RBS), and restriction sites for cloning, so that each cloned gene was under its own promoter and RBS. The multi-monocistronic vector, pNV18L2 containing transcriptional terminator showed better efficiency in reporter gene assay. Thus, multiple genes involved in the biogenesis of pyrrole moiety (ngnN2, ngnN3, ngnN4, and ngnN5 from Nocardia sp. CS682), glucose utilization (glf and glk from Zymomonas mobilis), and malonyl-CoA synthesis (accA2 and accBE from Streptomyces coelicolor A3 (2)), were cloned in pNV18L2. Further statistical optimization of specific precursors (proline and glucose) and their feeding time led to ~84.9 mg/L nargenicin from Nocardia sp. GAP, which is ~24-fold higher than Nocardia sp. CS682 (without feeding). Furthermore, pikC from Streptomyces venezuelae was expressed to generate Nocardia sp. PikC. Nargenicin A1 acid was characterized as novel derivative of nargenicin A1 produced from Nocardia sp. PikC by mass spectrometry (MS) and nuclear magnetic resonance (NMR) analyses. We also performed comparative analysis of the anticancer and antibacterial activities of nargenicin A1 and nargenicin A1 acid, which showed a reduction in antibacterial potential for nargenicin A1 acid. Thus, the development of an efficient synthetic biological platform provided new avenues for enhancing or structurally diversifying nargenicin A1 by means of pathway designing and engineering.

Opportunistic bacterial, viral and fungal infections of the lung

Opportunistic infections are a major cause of morbidity and mortality in severely immunocompromised patients, such as those receiving chemotherapy or biological therapies, patients with haematological malignancy, aplastic anaemia or HIV infection, and recipients of solid-organ or stem cell transplants. The type and degree of the immune defect dictate the profile of potential opportunistic pathogens; T-cell-mediated defects increase the risk of viral (cytomegalovirus, respiratory viruses) and Pneumocystis jirovecii infections, whereas neutrophil defects are associated with bacterial pneumonia and invasive aspergillosis. However, patients often have combinations of immune defects, and a wide range of other opportunistic infections can cause pneumonia. Importantly, conventional non-opportunistic pathogens are frequently encountered in immunocompromised hosts and should not be overlooked. The radiological pattern of disease (best assessed by computed tomography) and speed of onset help to identify the likely pathogen(s); radiological imaging can subsequently be supported by targeted investigation including the early use of bronchoscopy in selected patients. Rapid and expert clinical assessment can identify the most likely pathogens, which can then be treated aggressively, providing the best opportunity for a positive clinical outcome.

Role of Nocardia in Activated Sludge

Activated sludge process is a biological process that is widely used in the domestic and industrial wastewater treatment in over the world. The foam formation is often reported in wastewater treatment plants which are related to this process. Some operational problems can be created by foaming, such as effluent quality deteriorates, the creation of malodorous, increased time requirements in order to plant maintenance, and in extreme cases, hazardous working conditions resulting from foam spilling out of the aeration basin and as well as increased in operational costs. There are different ways to overcome this problem, such as reduce air flows into the aeration basin, reduction in the grease and oil content of the wastewater, surface and return activated sludge (RAS) chlorination, anoxic and anaerobic selectors, solid retention time (SRT) control and antifoams and organic polymer addition. On the other hand, rapid and accurate identification of the foam causes is in the first step to control bulking and foaming. Foam problem is often created by filamentous bacteria, such as Nocardia and Gordonia species. This bacterium has a role important in activated sludge.

Evaluation and enhancement of heavy metals bioremediation in aqueous solutions by Nocardiopsis sp. MORSY1948, and Nocardia sp. MORSY2014

An analysis of wastewater samples collected from different industrial regions of Egypt demonstrated dangerously high levels of nickel (0.27-31.50mgL(-1)), chromium (1.50-7.41mgL(-1)) and zinc (1.91-9.74mgL(-1)) in the effluents. Alarmingly, these heavy metals are among the most toxic knownones to humans and wildlife. Sixty-nine Actinomycete isolates derived from contaminated sites were evaluated under single, binary, and ternary systems for their biosorption capacity for Ni(2+), Cr(6+) and Zn(2+) from aqueous solutions. The results of the study identified isolates MORSY1948 and MORSY2014 as the most active biosorbents. Phenotypic and chemotypic characterization along with molecular phylogenetic evidence confirmed that the two strains are members of the Nocardiopsis and Nocardia genera, respectively. The results also proved that for both the strains, heavy metal reduction was more efficient with dead rather than live biomass. The affinity of the dead biomass of MORSY1948 strain for Ni(2+), Cr(6+) and Zn(2+) under the optimized pH conditions of 7, 8 and 7, respectively at 40°C temperature with 0.3% biosorbent dosage was found to be as follows: Ni(2+) (87.90%)>Zn(2+) (84.15%)>Cr(6+) (63.75%). However, the dead biomass of MORSY2014 strain under conditions of pH 8 and 50°C temperature with 0.3% biosorbent dose exhibited the highest affinity which was as follows: Cr(6+) (95.22%)>Ni(2+) (93.53%)>Zn(2+) (90.37%). All heavy metals under study were found to be removed from aqueous solutions in entirety when the sorbent dosage was increased to 0.4%.

Clinical significance, antimicrobial susceptibility and molecular identification of Nocardia species isolated from children with cystic fibrosis

Nocardia is an opportunistic pathogen that causes respiratory infections in immunocompromised patients. The aim of this study was to analyze the epidemiology, clinical significance and antimicrobial susceptibility of Nocardia species isolated from eight children with cystic fibrosis. The isolated species were identified as Nocardia farcinica, Nocardia transvalensis, Nocardia pneumoniae, Nocardia veterana and Nocardia wallacei. N. farcinica was isolated in three patients and all of them presented lung affectation with a chronic colonization and pneumonia. N. farcinica showed resistance against gentamicin, tobramycin, cefotaxime, but was susceptible to trimethoprim-sulfamethoxazole and amikacin. N. transvalensis, which was isolated from two patients, showed an association with chronic colonization. N. transvalensis was resistant to tobramycin and amikacin, but susceptible to ciprofloxacin, trimethoprim-sulfamethoxazole and cefotaxime. N. veterana, N. pneumoniae and N. wallacei were isolated from three different patients and appeared in transitory lung colonization. N. veterana and N. pneumoniae were susceptible to imipenem, trimethoprim-sulfamethoxazole, amikacin, tobramycin, and cefotaxime. N. wallacei was resistant to amikacin, tobramycin, imipenem, and trimethoprim-sulfamethoxazole and susceptible to ciprofloxacin and cefotaxime. All the isolates were identified up to species level by 16S rRNA gene sequencing. The presence of Nocardia in the sputum of patients with cystic fibrosis is not always an indication of an active infection; therefore, the need for a treatment should be evaluated on an individual basis. The detection of multidrug-resistant species needs molecular identification and susceptibility testing, and should be performed for all Nocardia infections.

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

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

Nocardiosis following hematopoietic stem cell transplantation

BACKGROUND

Nocardia species are ubiquitous environmental organisms that can cause a diverse spectrum of disease. Clinical manifestations range from localized skin and soft tissue infections to life-threatening pulmonary, central nervous system, and/or disseminated infections. Patients with hematologic malignancies undergoing hematopoietic stem cell transplantation (HSCT) are at risk for nocardiosis, and further data in regard to characteristics of disease in this population are warranted.

METHODS

We performed retrospective chart review of patients post allogeneic HSCT at Moffitt Cancer Center in Florida diagnosed with nocardiosis from 2003 to 2013.

RESULTS

In a decade, 15 cases of nocardiosis were identified. The majority of patients were men (11/15). The median age was 55 years (range 25-65). The most common type of transplant was matched-related donor (n = 8), followed by matched-unrelated donor (n = 3), mismatched-unrelated donor (n = 3), and double umbilical cord (n = 1). Ten received myeloablative conditioning (MAC) regimens. Twelve of 15 patients were on prednisone, 10 of which were on a total daily dose ≥20 mg. The median time from transplant to first positive culture was 10 months (range 1.5-93). Pulmonary nocardiosis was the most prevalent manifestation at 87%. Disseminated disease (2 or more sites of infection) was seen in 47%, whereas blood cultures were positive in 27% of the total cohort. The most common species was Nocardia nova (n = 4). At the time of diagnosis, 20% of the patients were receiving prophylaxis for Pneumocystis jirovecii pneumonia (PJP) with trimethoprim-sulfamethoxazole (TMP-SMX). Susceptibility data were available for 8 patients: all 8 samples were susceptible to TMP-SMX. Nocardiosis was treated with 2 or more active drugs in 93% of the patients. Overall mortality was 53%, with nocardiosis attributed as the cause in 62.5% (5/8). The absolute lymphocyte count at time of diagnoses was significantly lower in patients who ultimately experienced treatment failure.

CONCLUSION

Infection with Nocardia species in allogeneic HSCT recipients appears to be a late complication of transplantation and most commonly involves the lung. Two-thirds of the cohort received a MAC regimen and the majority of the patients were receiving steroids at the time of diagnosis. Most patients were not receiving TMP-SMX for PJP prophylaxis at the time of nocardiosis diagnosis, and TMP-SMX may therefore have a protective effect.

Rare actinomycetes Nocardia caishijiensis and Pseudonocardia carboxydivorans as endophytes, their bioactivity and metabolites evaluation

Two strains identified as Nocardia caishijiensis (SORS 64b) and Pseudonocardia carboxydivorans (AGLS 2) were isolated as endophytes from Sonchus oleraceus and Ageratum conyzoides respectively. The analysis of their extracts revealed them to be strongly bioactive. The N. caishijiensis extract gave an LC50 of 570 μg/ml(-1) in the brine shrimp cytotoxicity assay and an EC50 of 0.552 μg/ml(-1) in the DPPH antioxidant assay. Antimicrobial activity was observed against Methicillin resistant Staphlococcus aureus (MRSA) and Escherichia coli ATCC 25922 (14 mm), Klebsiella pneumoniae ATCC 706003 (13 mm), S. aureus ATCC 25923 (11 mm) and Candida tropicalis (20 mm). For the extract of P. carboxydivorans the EC50 was 0.670 μg/ml(-1) and it was observed to be more bioactive against Bacillus subtilis DSM 10 ATCC 6051 (21 mm), C. tropicalis (20 mm), S. aureus ATCC 25923 (17 mm), MRSA (17 mm), E. coli K12 (W1130) (16 mm) and Chlorella vulgaris (10 mm). The genotoxicity testing revealed a 20 mm zone of inhibition against the polA mutant strain E. coli K-12 AB 3027 suggesting damage to the DNA and polA genes. The TLC and bioautography screening revealed a diversity of active bands of medium polar and nonpolar compounds. Metabolite analysis by HPLC-DAD via UV/vis spectral screening suggested the possibility of stenothricin and bagremycin A in the mycelium extract of N. caishijiensis respectively. In the broth and mycelium extract of P. carboxydivorans borrelidin was suggested along with α-pyrone. The HPLC-MS revealed bioactive long chained amide derivatives such as 7-Octadecenamide, 9, 12 octadecandienamide. This study reports the rare actinomycetes N. caishijiensis and P. carboxydivorans as endophytes and evaluates their bioactive metabolites.

Pulmonary nocardiosis in fine-needle aspiration cytology smears: Report of four cases

Nocardia has been recognized as a significant opportunistic pathogen in organ transplant patients; however, it is an uncommon pathogen in immunocompetent patients. It may mimic other infectious diseases both clinically and radiologically. We report four cases of pulmonary nocardiosis in three immunocompromised and one immunocompetent patients on fine-needle aspiration cytology (FNAC). Two patients presented with lung consolidation while two had cavitatory lesions. FNAC smears showed inflammatory cells composed of polymorphs and histiocytes along with necrosis. Occasional epithelioid cell granuloma was seen in one case. Modified Ziehl-Neelsen (ZN) stain was performed which highlighted long slender filamentous branching organisms conforming to the morphology of Nocardia. Thus, a suspicion for nocardiosis should be kept while assessing cytologic material especially in immunocompromised individuals. The diagnosis can be confirmed by special stains and culture studies; however, a high index of clinical suspicion is required so that appropriate culture media can be used for high diagnostic yield. FNAC is of help in providing immediate and accurate diagnosis of nocardiosis, thus helping in appropriate medical management.

Nocardia abscessus-related intracranial aneurysm of the internal carotid artery with associated brain abscess: A case report and review of the literature

Nocardia infections primarily begin in the lungs and spread hematogenously to other sites in the body. Thus, a Nocardia brain abscess is not a completely uncommon occurrence. However, a Nocardia brain abscess complicated by a middle cerebral artery and infectious intracranial aneurysm is a very rare clinical entity. We present a case of an infectious intracranial aneurysm with an associated Nocardia brain abscess that required surgical intervention and resection. The patient was an immunocompetent 60-year-old male who presented with a chief complaint of headache and was found to have an infected intracranial aneurysm and cerebral abscess. He underwent drainage of the abscess with subsequent resection of the infected aneurysm. Cultures from both the blood vessel and brain tissue grew Nocardia abscessus. He was successfully treated with 6 weeks of ceftriaxone and high-dose trimethoprim-sulfamethoxazole. Infectious intracranial aneurysms of the brain caused by Nocardia are rare occurrences, and only a single previous case has been described in the literature. The outcomes of this condition can be catastrophic if it is not treated with a combination of surgery and intravenous antibiotics. The guidelines for the management of this infection are not well defined at this time.

Nocardial brain abscess in a patient with pulmonary alveolar proteinosis

Brain abscesses caused by Nocardia are rare but have a very high mortality and specific requirements of antibiotic treatment. Nocardial brain abscesses are mainly found in patients with predisposing conditions such as pulmonary alveolar proteinosis (PAP), a disease associated with chronic exposure to silica dust. We present a case of multiple nocardial brain abscesses in a man with PAP probably due to long-term occupational exposure to silica dust. Conclusively, in patients presenting brain abscesses and a history of chronic exposure to silica dust, PAP and opportunistic nocardial infection should always be considered as possible diagnoses.

Subtentorial cerebral nocardiosis in immunocompetent patients: CT and MR imaging findings

PURPOSE

To describe the clinical presentation and computed tomography (CT) and magnetic resonance imaging (MRI) appearances of subtentorial nocardia cerebral abscesses developing in immunocompetent patients.

PATIENTS AND METHODS

The clinical findings and the results of CT and MRI examinations of three immunocompetent patients with nocardiosis located initially only in the subtentorial region were studied. Three patients underwent CT examination and two patients had MRI.

RESULTS

Clinically, two patients had cerebellar syndrome and the third had meningism with fever. The diagnosis of nocardiosis was bacteriologically confirmed by demonstrating the organism in lumbar puncture fluid in one patient and by an aspiration biopsy of the abscess in the other two. Two of the patients improved under targeted antibiotic therapy whereas the third patient died. The main imaging features of the lesions were a multiloculated appearance with peripheral enhancement after intravenous administration of iodinated contrast material on CT and a multicystic appearance on MRI, with a peripheral hypointense rim on T2-weighted images, a relatively minor mass effect and a multiloculated appearance on gadolinium-chelate enhanced T1-weighted images.

CONCLUSION

The clinical presentation of cerebral nocardiosis is relatively non-specific. A microcystic lesion surrounded by hypointensity on T2-weighted MR images with a multiloculated pattern after gadolinium chelate administration on T1-weighted MR images in association with a relatively minor mass effect should suggest this diagnosis even if the lesion is single and in the absence of immunosuppression.

Identification of Nocardia species using matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry

BACKGROUND

The MALDI (matrix-assisted laser desorption/ionization) Biotyper system for bacterial identification has already been utilized in clinical microbiology laboratories as a successful clinical application of protoemics. However, in cases of Nocardia, mass spectra suitable for MALDI Biotyper identification are often not obtained if such specimens are processed like general bacteria. This problem is related to the insufficiencies in bacterial spectrum databases that preclude accurate specimen identification. Here, we developed a bacterial processing method to improve mass spectra from specimens of the genus Nocardia. In addition, with the new processing method, we constructed a novel in-house bacterial database that combines a commercial database and mass spectra of Nocardia strains from the Department of Clinical Laboratory at Chiba University Hospital (DCLC) and the Medical Mycology Research Center at Chiba University (MMRC).

RESULTS

The newly developed method (Nocardia Extraction Method at DCLC [NECLC]) based on ethanol-formic acid extraction (EFAE) improved mass spectra obtained from Nocardia specimens. The Nocardia in-house database at Chiba University Hospital (NDCUH) was then successfully validated. In brief, prior to introduction of the NECLC and NDCUH, 10 of 64 (15.6%) clinical isolates were identified at the species level and 16 isolates (25.0%) could only be identified at the genus level. In contrast, after the introduction, 58 isolates (90.6%) were identified at the species level and 6 isolates (9.4%) were identified at the genus level.

CONCLUSIONS

The results of this study suggest that MALDI-TOF (time-of-flight) Biotyper system can identify Nocardia accurately in a short time in combination with a simple processing method and an in-house database.

Nocardia isolation from clinical samples with the paraffin baiting technique

BACKGROUND

The genus Nocardia is a cause of infection in the lungs, skin, brain, cerebrospinal fluid, eyes, joints and kidneys. Nocardia isolation from polymicrobial specimens is difficult due to its slow growth. Several methods have been reported for Nocardia isolation from clinical samples. In the current study, we used three methods: paraffin baiting technique, paraffin agar, and conventional media for Nocardia isolation from various clinical specimens from Iranian patients.

METHODS

In this study, we examined 517 samples from various clinical specimens such as: sputum of patients with suspected tuberculosis, bronchoalveolar lavage, sputum of patients with cystic fibrosis, tracheal aspirate, cutaneous and subcutaneous abscesses, cerebrospinal fluid, dental abscess, mycetoma, wound, bone marrow biopsy, and gastric lavage. All collected specimens were cultured on carbon-free broth tubes (paraffin baiting technique), paraffin agar, Sabouraud dextrose agar, and Sabouraud dextrose agar with cycloheximide and were incubated at 35°C for one month.

RESULTS

Seven Nocardia spp. were isolated with paraffin baiting technique, compared with 5 positive results with the paraffin agar technique and 3 positive results with Sabouraud dextrose agar with and without cycloheximide. The prevalence of nocardial infections in our specimens was 5.28%.

CONCLUSION

In the present study, the use of the paraffin baiting technique appeared to be more effective than other methods for Nocardia isolation from various clinical specimens.

Diversity and frequency of Nocardia spp. in the soil of Isfahan province, Iran

OBJECTIVE

To isolate and identify Nocardia spp. from soil in different regions of Isfahan province in the center of Iran.

METHODS

This study was conducted in 32 districts (16 cities and 16 villages) in Isfahan province during two years. A total of 800 soil samples from these regions were studied by using kanamycin. The isolated Nocardia species were examined by gram and acid-fast staining and were identified biochemically and morphologically. The frequency and distribution of Nocardia spp. were determined in relation to different factors such as soil pH and temperate climate.

RESULTS

From 153 (19.1%) Nocardia isolates identified, Nocardia asteroids (N. asteroids) complex (45.5%) and Nocardia brasiliensis (N. brasiliensis) (24.7%) were the most frequently isolated species, followed by Nocardia otitidiscaviarum (2.2%), Nocardiopsis dassonvillei, Actinomadura actinomadura (each 1.7%) and Nocardia transvalensis (1.1%) and also unknown spp. (23.0%). In this study, most species (54.4%) of Nocardia, especially N. asteroides complex were isolated from soils with pH: 7.01-8, whereas in pH: 8.01-9 more N. brasiliensis was isolated. The most Nocardia spp. was detected from regions with semi-nomadic and temperate climate (41.1%).

CONCLUSIONS

N. asteroids complex is more prevalent in Isfahan province and soil can be a potential source of nocardiosis infections. It is to be considering that climate and soil pH are involved in the frequency and diversity of aerobic Actinomycetes.

Disseminated nocardiosis during systemic steroid therapy for the prevention of esophageal stricture after endoscopic submucosal dissection

An 85-year-old man underwent endoscopic submucosal dissection for a large superficial esophageal epithelial neoplasm, which required removal of 95% of the circumference of the esophageal mucosa. Steroids were given orally to prevent esophageal stricture starting on day 3 postoperatively. In the 6th week of steroid treatment, he developed high fever without other symptoms. Chest computed tomography revealed a nodular lesion in the lung. Sputum sample showed Gram-positive, branching, filamentous bacteria, and a diagnosis of nocardiosis was suspected. Brain magnetic resonance imaging revealed multiple focal lesions which indicated dissemination of nocardiosis. Trimethoprim-sulfamethoxazole was immediately started, which led to the disappearance of pulmonary and cerebral nocardiosis with alleviation of fever. Recently, oral steroid treatment has been widely used for the prevention of esophageal stricture. However, the present case indicates the risk of life-threatening infection and the importance of close monitoring of this treatment.

Cerebral nocardiosis

Cerebral Nocardiosis is a rare, challenging, opportunistic infectious disease of the central nervous system occurring in both immunocompetent and immunocompromised hosts. It often results in intraparenchymal abscess formation, which represents only 2% of all cerebral abscesses. The diagnosis of cerebral Nocardiosis is seldom based on imaging. Bacteriological diagnosis is often reached only after surgical excision of the abscess. We report a rare case of brain abscess caused by Nocardia species in a 20-year-old immunocompromised lady. Total surgical excision of the abscess, prompt bacteriological diagnosis based on smear and culture of the pus and initiation of specific antimicrobial therapy (trimethoprim and sulfamethoxazole) resulted in good clinical outcome.

Nocardia co-infection in patients with pulmonary tuberculosis

Background:

Tuberculosis (TB) remains as one of the most serious infectious diseases in the world. Pulmonary tuberculosis can occur with other pulmonary diseases caused by opportunistic organisms such as Nocardia spp. particularly in immunocompromised patients. Therefore, diagnosis of co-infection at the early stage of the disease could be lifesaving.

Objectives:

The goal of this study was to detect Mycobacterium tuberculosis and Nocardia spp. in sputum specimens in order to assess the concomitant nocardiosis and tuberculosis in patients with suspected pulmonary tuberculosis.

Patients and Methods:

From March 2011 to April 2012, 189 sputum specimens were obtained from patients who were suspected of having pulmonary tuberculosis. Out of 189 samples, 32 of the samples belonged to hospitalized HIV-infected patients. Samples were examined by Gram and Ziehl-Nelsen staining, culture and PCR methods.

Results:

From 157 sputum specimens, positive samples by acid fast staining, culture and PCR for M. tuberculosis were reported for 7.6% (12/157), 10.1% (16/157) and 7% (11/157) of samples, respectively. No results were obtained by the described methods for Nocardia spp. Among 32 samples of HIV-infected patients, four (12.5%) had positive results for acid fast staining, culture and PCR detecting M. tuberculosis while only two samples had positive results for Nocardia spp. by PCR and no results were reported by culture, Gram and acid fast staining for this organism.

Conclusions:

Concurrent pulmonary nocardiosis and tuberculosis is frequent in HIV-infected patients. Rapid and sensitive methods such as PCR are recommended for detection of such co-infections.

Nocardiosis in 132 patients with cancer: microbiological and clinical analyses

OBJECTIVES

To correlate the microbiological and clinical features of infections caused by Nocardia species.

METHODS

We determined the species and drug susceptibility of 138 Nocardia strains isolated from 132 patients at the University of Texas M. D. Anderson Cancer Center (Houston, TX) from 2002 through 2012 and analyzed the clinical features.

RESULTS

The 132 patients included 82 men and 50 women with a mean age of 59.1 years. All except two had underlying cancer, and 47 (35.6%) also received a stem cell transplant. These patients experienced 136 episodes of Nocardia infection, including pulmonary infection, abscess of deep skin and soft tissue, bacteremia and dissemination, and brain abscess. The 138 Nocardia strains involved 27 species, of which 20 species have been described since 2000. Common species included Nocardia nova, Nocardia cyriacigeorgica, Nocardia farcinica, and Nocardia abscessus, together accounting for 59.4%. N nova caused most bacteremia cases, whereas N farcinica caused most of the skin and brain infections. Infections with a few recent species likely represented first confirmation or report of human infections. Antimicrobial susceptibility tests of 117 strains showed that they were all susceptible to trimethoprim-sulfamethoxazole and linezolid but variably susceptible to other drugs depending on species. Most patients who were treated for the infection showed improvement or resolution.

CONCLUSIONS

Diverse Nocardia species can cause secondary infections in patients with cancer. Timely species identification and antimicrobial susceptibility tests may guide treatment.

Recurrent Nocardia Sepsis in a Patient With Sickle Cell Anemia Receiving Continuous Deferoxamine

Nocardia species are ubiquitous soil-borne organisms that most commonly cause invasive disease in patients with defective cell-mediated immunity. We report a case of recurrent Nocardia sepsis in a patient with sickle cell disease and chronic iron overload, who was undergoing high-dose infusions of deferoxamine through a central venous catheter.

Immunomodulatory effect of diethylcarbamazine in mice infected with Nocardia brasiliensis

We tested whether diethylcarbamazine (DEC) or ivermectin (IVM), both antiparasitic drugs with reported immunomodulatory properties, were able to affect the immune system to potentiate host defense mechanisms and protect against actinomycetoma in a mouse model. Male BALB/c mice of 10-12 weeks of age were injected with either Nocardia brasiliensis or saline solution. Recorded were the effects of a treatment by DEC (6 mg/kg per os daily for one week) or IVM (200 μg/kg subcutaneously on days 1 and 3) on (i) the development of mycetoma lesion, (ii) the expression of reactive oxygen intermediates (ROI) by phagocytes, (iii) the proliferation index of lymphocytes and (iv) antibody production of IgG and IgM. After an initial lesion in all mice, DEC inhibited a full development and progression of actinomycetoma resulting in a reduced lesion size (p < 0.001). IVM had no inhibitory effect on the development of mycetoma. Furthermore, DEC treatment was associated with a significant enhancement of ROI expression (p < 0.05) by polymorphonuclear neutrophils at day 3 after infection. Lymphocyte proliferation in response to N. brasiliensis antigens and concanavalin A in DEC-treated group was higher than in non-treated group at day 21 and 28 postinfection (p < 0.01). Significant changes in antibody response were not observed. By all parameters tested, DEC was superior to IVM regarding immunostimulatory potency. In conclusion, DEC expressed an in vivo influence on the immune status during the infection by N. brasiliensis leading to retrogression of the mycetoma and increasing cellular immune responses. Our findings may indicate a potential use of DEC as a putative adjuvant in infectious disease or vaccination.

Nocardial brain abscess in an immunocompromised old patient: a case report and review of literature

BACKGROUND

Nocardial brain abscess is a rare central nervous system (CNS) infection with high morbidity and mortality. The infection is acquired through inhalation or direct contact with the bacteria, and could spreads through blood transmission. Nocardial brain abscess is usually associated with immunocompromised patients, but sometimes may appear in healthy individuals. Treatment is based on stereotaxic aspiration or surgical resection, and antibiotics therapy for several months.

CLINICAL PRESENTATION

We presented one case of nocardial brain abscess treated at our department with review the literature. The patient was 65-year-old with ANCA polyangitis. She had oral methylprednisolone tablets treatment for over 6 months. The patient was treated with surgical evacuation and long-term antibiotics. The patient recovered well at discharge.

CONCLUSION

Nocardial brain abscess is a rare CNS infection that needs to be differentiated from other brain lesions. It could occur in immunocompromised patients or healthy individuals. Treatment includes surgical intervention and long-term antibiotics therapy.

Clinical findings of 40 patients with nocardiosis: A retrospective analysis in a tertiary hospital

To the best of our knowledge, no Chinese case studies concerning Nocardia infection have been published to date. Therefore, the present study aimed to retrospectively evaluate the risk factors, clinical features, imaging results, laboratory abnormalities, treatments and outcomes of nocardiosis in a Chinese tertiary hospital. Data collected from patients with laboratory-confirmed nocardiosis were retrospectively analyzed. A total of 40 patients who had a positive culture of Nocardia were included. The median time between the onset of symptoms and diagnosis was 42 days. Underlying diseases were identified in 72.5% of the patients of which diabetes was the most common (32.5%). The most important risk factor was corticosteroid administration. Fever and cough were common clinical symptoms. The pleuropulmonary (85%) were the most frequently involved sites and the disseminated disease rate was 30.0%. Frequent chest computed tomography scans revealed the presence of airspace opacities, nodules and masses, in addition to cavitary lesions that were particularly common among the study group. Brain images revealed lesions associated with abscesses. The majority of the patients (71.1%) were treated with trimethoprim sulfamethoxazole alone or in combination with other drugs. The in-hospital mortality rate was 15.0%. Disseminated disease, immunocompromised patients, an older age, brain involvement and concomitant infections were associated with a poor prognosis. Nocardiosis is an uncommon but emerging disease. The present study reports the first case series on nocardiosis from China and provides important information on the clinical features and risk factors of nocardiosis. Early recognition of the disease and the initiation of appropriate treatment are essential for a good prognosis.

DNA extraction from nocardia species for special genes analysis using PCR

BACKGROUND

Nocardia species have a complex cell wall structure similar to that of mycobacteria, and the extraction of DNA from this bacterium is extremely difficult. Currently, to identify Nocardia species particularly, it is essential to utilize molecular techniques.

AIMS

In the present study, we investigated STET (sodium chloride-TRIS-EDTA-triton) buffer for the extraction of high-quality genomic DNA from 20 clinical and environmental isolates.

MATERIALS AND METHODS

The extracted DNA was evaluated for portion of the 16S rRNA, 65-kDa heat-shock protein and 16S rRNA genes via polymerase chain reaction.

RESULTS

The extracted DNA had high molecular mass, and its concentration and purity was suitable when tested in 1% agarose gel, and using UV spectrophotometry. Amplification of three different genes was successfully performed.

CONCLUSION

This paper reveals an inexpensive, reproducible and efficient method of DNA extraction from Nocardia species, which is appropriate for accurate identification of this bacterium via polymerase chain reaction and polymerase chain reaction-restriction fragment length polymorphism.

Pulmonary nocardiosis: a clinical analysis of 59 cases

BACKGROUND

Pulmonary nocardiosis is a rare but severe infection caused by Nocardia species. This study aimed at describing the clinical characteristics and prognosis of pulmonary nocardiosis.

METHODS

An observational, retrospective study was undertaken of patients diagnosed with pulmonary nocardiosis over a 13-year period at the Kinki-Chuo Chest Medical Center, Osaka, Japan.

RESULTS

Seven patients with airway nocardial colonization and 59 patients with pulmonary nocardiosis were identified, one of whom had disseminated nocardiosis. Patients with pulmonary nocardiosis were predominantly male patients (73%), with a mean age of 66 (range, 15-88) years. New-onset cough and dyspnea were the most common manifestations (76%). Although 52 (88%) patients had at least one underlying pulmonary disease, most patients did not appear to be systemically immunocompromised. The predominant abnormality on chest computed tomography in pulmonary nocardiosis was airspace consolidation (52%), sometimes associated with cavitation. Multivariate Cox proportional-hazards analysis revealed the following significant and independent risk factors for overall mortality: age >68 years (hazard ratio [HR], 4.7; 95% confidence interval [CI], 1.6-14; p=0.05), pulmonary aspergillosis (HR, 8.8; 95% CI, 2.4-33; p=0.01), and trimethoprim/sulfamethoxazole (TMP-SMZ) resistance (HR, 4.3; 95% CI, 1.6-11; p=0.04).

CONCLUSIONS

Clinicians should be aware that pulmonary nocardiosis can occur even in immunocompetent patients, especially those with an underlying pulmonary disease. In pulmonary nocardiosis, older age, pulmonary aspergillosis, and TMP-SMZ resistance are associated with increased risk of mortality.

Potential consequences of essential drug shortages in Canada: Brain abscess due to Nocardia farcinica associated with dapsone prophylaxis for Pneumocystis jirovecii pneumonia

In 2012, Canadian pharmacies experienced a shortage of trimethoprim-sulfamethoxazole tablets. Drug shortages may result in unintended clinical consequences such as infection with pathogens against which the alternative medication is ineffective. This is highlighted in the present article, which describes a case of brain abscess due to Nocardia species that developed while receiving dapsone as an alternative for prophylaxis against Pneumocystis jirovecii pneumonia in a highly immune-suppressed patient. Clinicians should be cognizant of these issues when prescribing alternative agents.

Tropical myelopathies

A large number of causal agents produce spinal cord lesions in the tropics. Most etiologies found in temperate regions also occur in the tropics including trauma, herniated discs, tumors, epidural abscess, and congenital malformations. However, infectious and nutritional disorders occur with higher prevalence in tropical regions. Among the most common infectious etiologies are tuberculous Pott's disease, brucellosis, and neuroborreliosis. Parasitic diseases such as schistosomiasis, neurocysticercosis, and eosinophilic meningitis are frequent causes of nontraumatic paraplegia. The retrovirus HTLV-1 is a cause of tropical spastic paraparesis. Nutritional causes of paraparesis include deficiencies of vitamin B12 and folate; endemic clusters of konzo and tropical ataxic myeloneuropathy are associated in Africa with malnutrition and excessive consumption of cyanide-containing bitter cassava. Other toxic etiologies of tropical paraplegia include lathyrism and fluorosis. Nutritional forms of myelopathy are associated often with optic and sensory neuropathy, hence the name tropical myeloneuropathies. Acute transverse myelopathy is seen in association with vaccination, infections, and fibrocartilaginous embolism of the nucleus pulposus. Multiple sclerosis and optic myelopathy occur in the tropics but with lesser prevalence than in temperate regions. The advent of modern imaging in the tropics, including computed tomography and magnetic resonance imaging, has allowed better diagnosis and treatment of these conditions that are a frequent cause of death and disability.

Primary lymphocutaneous nocardiosis associated with gardening: A case series

Most cases of nocardiosis are seen in immunocompromised patients. Primary lymphocutaneous is a relatively uncommon presentation of this disease that may also occurs in normal hosts. Diagnosing this infection requires a high index of suspicion since cultures can take several days to exhibit growth. The microbiology laboratory must therefore be notified about cases in which this pathogen is suspected. We report four cases of primary lymphocutaneous norcardiosis. Of particular interest is the association of three of these cases with gardening.