Fatal cases of disseminated nocardiosis: challenges to physicians and clinical microbiologists - Case report

Despite the development in the identification of Nocardia spp., common challenges exist in the laboratory diagnosis and management of nocardiosis. We report two cases of disseminated nocardiosis in a patient with hematologic disorder and in a patient with systemic lupus erythematosus, where the cooperation between various specialists was essential to set up the adequate diagnosis of disseminated nocardiosis.

Nocardia Tenerifensis Genome Identification in a Cutaneous Granuloma of a Cat

An adult Domestic Longhair cat developed a subcutaneous mass in its tail. Histologically, this mass consisted of ill-defined pyogranulomas centered around aggregates of gram-positive, acid-fast filamentous bacteria, consistent with Nocardia. Due to the lack of fresh samples, DNA was extracted from formalin-fixed paraffin-embedded tissue sections and subjected to polymerase chain reaction amplification and DNA sequencing of 16S ribosomal RNA gene encompassing Nocardia sp.-specific sequences. Sequences analyzed using the GenBank database revealed 99.5% homology with Nocardia spp. and had the highest sequence homology of 98.2% with Nocardia tenerifensis among Nocardia spp. To the authors’ knowledge, this is the first report of detection of N. tenerifensis genome associated with cutaneous nocardiosis in an animal.

Nocardia elegans infection: a case report and literature review

A case of disseminated nocardiosis caused by Nocardia elegans in a 72-year-old man with rheumatoid arthritis, treated with tacrolimus and prednisolone, is reported herein. The patient had impaired vision and was diagnosed with endophthalmitis and an abdominal skin abscess. He was started on trimethoprim-sulfamethoxazole treatment, followed by cefepime. The patient was then switched to a combination of imipenem-cilastatin and minocycline. Although the patient survived as a result of surgery and prolonged antibiotic treatment, he eventually lost vision after the infection became resistant to antibiotic treatment. Molecular analysis of samples from the abscess and vitreous fluid confirmed the extremely rare pathogen N. elegans, which accounts for only 0.3-0.6% of infections caused by Nocardia species. This organism is almost always associated with pulmonary infection, and disseminated infections are rare. As with previously reported norcardial infections, the current case was treated successfully with trimethoprim-sulfamethoxazole, carbapenems, and aminoglycosides. However, the clinical characteristics of this organism remain unclear. Further studies are therefore required to develop more effective treatment protocols for disseminated nocardiosis caused by this problematic pathogen.

NOCARDIA BEIJINGENSIS BRAIN ABSCESS IN AN HIV INFECTED PATIENT: A FIRST CASE REPORT AND LITERATURE REVIEW

We report here brain abscesses caused by Nocardia beijingensis in a 59-year-old-Thai male with human immunodeficiency virus (HIV) infection presenting with progressive right sided hemiparesis. A computed tomography scan of the brain showed multiple brain abscesses. A stereotactic brain biopsy and 16S rRNA sequencing showed Nocardia beijingensis. The patient was treated with trimethoprim-sulfamethoxazole and recovered completely. As far as we are aware, this is the first reported case of a brain abscess in an HIV infected patient due to Nocardia beijingensis.

Isolation and genetic characterization of Nocardia seriolae from snubnose pompano Trachinotus blochii in Vietnam

A total of 480 cage-cultured fish were collected from 4 coastal provinces in central Vietnam to investigate the causative agent of nocardiosis. Fish displayed unique characteristics such as paleness and lethargy and exhibited haemorrhages and ulcers on the skin. Prominent white nodules varying in size were observed in the spleen, kidney, and liver. Furthermore, histopathological sections showed typical granulomatous lesions in these organs. Using the Ziehl-Neelsen staining method, isolated bacteria exhibited acid-fast, bead-like filament morphology when cultured in brain-heart infusion medium or Ogawa medium. Phylogenetic analysis of 16S rDNA confirmed that the isolated bacterium was Nocardia seriolae. This study demonstrates for the first time an outbreak of N. seriolae in snubnose pompano in central Vietnam.

Diagnosis of Nocardia paucivorans central nervous system infection by DNA sequencing from paraffin-embedded tissue

Infections by Nocardia spp. are generally regarded as opportunistic diseases in immunocompromised patients, but can also affect immunocompetent subjects. Such infections represent an important diagnostic challenge for clinicians and microbiologists, and diagnosis is frequently delayed or even conducted post mortem. A 54-year-old man was admitted to our hospital because of ventriculitis and relapsing brain abscess. Five months prior, this patient had undergone external ventricular drain and surgery for a cerebellar abscess. Histopathology demonstrated pyogenic inflammatory reaction, microbiologic investigations proved negative and empiric antimicrobial therapy was administered for a total of eight weeks. Six weeks later, the patient developed relapsing neurologic manifestations. On reviewing the patient's clinical history it emerged that the patient had suffered pneumonia two months prior to neurosurgery, treated with amoxicillin/clavulanate 3g a day and levofloxacin 500mg a day for three weeks. On the CNS relapsing manifestations, nocardiosis was suspected and DNA sequencing from the formalin-fixed paraffin-embedded cerebellar tissue collected during neurosurgery allowed diagnosis of Nocardia paucivorans infection. The patient received medical therapy for 11 months. At follow-up, eight months after treatment was discontinued, the patient was aymptomatic. Nocardia spp. infections need to be suspected not only in immunocompromised, but also in immunocompetent patients. Proper samples need to be collected for proper microbiologic investigations. Paraffin-embedded tissue genomic sequencing can be a useful tool for diagnosis of nocardiosis.

Production, Structural Elucidation, and In Vitro Antitumor Activity of Trehalose Lipid Biosurfactant from Nocardia farcinica Strain

The objective of this study was to isolate and identify the chemical structure of a biosurfactant produced by Nocardia farcinica strain BN26 isolated from soil, and evaluate its in vitro antitumor activity on a panel of human cancer cell lines. Strain BN26 was found to produce glycolipid biosurfactant on n-hexadecane as the sole carbon source. The biosurfactant was purified using medium-pressure liquid chromatography and characterized as trehalose lipid tetraester (THL) by nuclear magnetic resonance spectroscopy and mass spectrometry. Subsequently, the cytotoxic effects of THL on cancer cell lines BV-173, KE-37 (SKW-3), HL-60, HL-60/DOX, and JMSU-1 were evaluated by MTT assay. It was shown that THL exerted concentration-dependent antiproliferative activity against the human tumor cell lines and mediated cell death by the induction of partial oligonucleosomal DNA fragmentation. These findings suggest that THL could be of potential to apply in biomedicine as a therapeutic agent.

Rejection, Recurrence, or Something Else?

Since the introduction of liver transplant as treatment for end-stage liver disease, thousands of lives have been saved. To prevent organ rejection, immunosuppression is given chronically and hence, patients are at increased risk for opportunistic infections related to immunosuppression, especially within the first year after the transplant. However, opportunistic infections can occur years after the transplantation. Disseminated nocardiosis is one of these infections, and although the common presentation includes involvement of skin, lungs, and central nervous system. We present an uncommon presentation of nocardiosis in which cholestasis and elevated liver enzymes predominate, mimicking organ rejection and liver disease recurrence. Infectious etiologies, including opportunistic microorganisms, must always be ruled out in patients presenting elevation in liver enzymes and cholestasis after liver transplant as early diagnosis can prevent complications such as re-transplantation and even death.

Report of an immunocompetent case with disseminated infection due to Nocardia otitidiscaviarum: Identification by 16S rRNA gene sequencing

Nocardia otitidiscaviarum belongs to the agents of opportunistic infections seen in immunocompromised patients, but may occur rarely in immunocompetent patients. In this report we described a case of a previously healthy 69-year-old woman with cerebral and retroperitoneal abscess due to Nocardia otitidiscaviarum. The patient was admitted to hospital because of loss of strength in her right arm and leg. Nocardia spp. was isolated from the abscess material. The intracranial lesions were drained by stereotactic craniotomy. The large abscess located around the left kidney was drained and microscopic examination of aspirated material showed Nocardia spp. For species identification, 16S rRNA gene sequencing was carried out and was 100% concordant with Nocardia otitidiscaviarum. Use of 16S rDNA gene sequencing for identification permits detection of rare aetiologic agents that cause brain abscesses.

Autochthonous Nocardia cerradoensis Infection in Humans, Spain, 2011 and 2014

Nocardia cerradoensis was first isolated in 2003 in the El Cerrado region of Brazil; since then, only 2 human infections, in France and Spain, have been reported. We describe 3 autochthonous cases in residents of Spain during 2011 and 2014. Together these cases support the idea of an emerging global pathogenic microorganism.

MOLECULAR IDENTIFICATION AND ANTIMICROBIAL RESISTANCE PATTERN OF SEVEN CLINICAL ISOLATES OF Nocardia spp. IN BRAZIL

Nocardia is a ubiquitous microorganism related to pyogranulomatous infection, which is difficult to treat in humans and animals. The occurrence of the disease is on the rise in many countries due to an increase in immunosuppressive diseases and treatments. This report of cases from Brazil presents the genotypic characterization and the antimicrobial susceptibility pattern using the disk-diffusion method and inhibitory minimal concentration with E-test® strips. In summary, this report focuses on infections in young adult men, of which three cases were cutaneous, two pulmonary, one neurological and one systemic. The pulmonary, neurological and systemic cases were attributed to immunosuppressive diseases or treatments. Sequencing analysis of the 16S rRNA segments (1491 bp) identified four isolates of Nocardia farcinica, two isolates of Nocardia nova and one isolate of Nocardia asiatica. N. farcinica was involved in two cutaneous, one systemic and other pulmonary cases; N. nova was involved in one neurological and one pulmonary case; and Nocardia asiatica in one cutaneous case. The disk-diffusion antimicrobial susceptibility test showed that the most effective antimicrobials were amikacin (100%), amoxicillin/clavulanate (100%), cephalexin (100%) and ceftiofur (100%), while isolates had presented most resistance to gentamicin (43%), sulfamethoxazole/trimethoprim (43%) and ampicillin (29%). However, on the inhibitory minimal concentration test (MIC test), only one of the four isolates of Nocardia farcinica was resistant to sulfamethoxazole/trimethoprim.

Case report: Actinomycetoma caused by Nocardia aobensis from Lao PDR with favourable outcome after short-term antibiotic treatment

BACKGROUND

Mycetoma is a neglected, chronic, localized, progressively destructive, granulomatous infection caused either by fungi (eumycetoma) or by aerobic actinomycetes (actinomycetoma). It is characterized by a triad of painless subcutaneous mass, multiple sinuses and discharge containing grains. Mycetoma commonly affects young men aged between 20 and 40 years with low socioeconomic status, particularly farmers and herdsmen.

METHODOLOGY/PRINCIPAL FINDINGS

A 30 year-old male farmer from an ethnic minority in Phin District, Savannakhet Province, Lao PDR (Laos) developed a painless swelling with multiple draining sinuses of his right foot over a period of approximately 3 years. X-ray of the right foot showed osteolysis of tarsals and metatarsals. Aerobic culture of sinus discharge yielded large numbers of Staphylococcus aureus and a slow growing Gram-positive rod. The organism was subsequently identified as Nocardia aobensis by 16S ribosomal RNA gene sequencing. The patient received antimicrobial treatment with amikacin and trimethoprim-sulfamethoxazole according to consensus treatment guidelines. Although slight improvement was noted the patient left the hospital after 14 days and did not take any more antibiotics. Over the following 22 weeks the swelling of his foot subsequently diminished together with healing of discharging sinuses.

CONCLUSION

This is the first published case of Actinomycetoma caused by Nocardia aobensis and the second case of Actinomycetoma from Laos. A treatment course of only 14 days with amikacin and trimethoprim-sulfamethoxazole was apparently sufficient to cure the infection, although long-term treatment up to one year is currently recommended. Treatment trials or prospective descriptions of outcome for actinomycetoma should investigate treatment efficacy for the different members of Actinomycetales, particularly Nocardia spp., with short-term and long-term treatment courses.

Temperature effects on biomass, geosmin, and 2-methylisoborneol production and cellular activity by Nocardia spp. and Streptomyces spp. isolated from rainbow trout recirculating aquaculture systems

Isolates of Nocardia cummidelens, Nocard ia fluminea, Streptomyces albidoflavus, and Streptomyces luridiscabiei attributed as the cause of "earthy-musty" off-flavor in rainbow trout (Oncorhynchus mykiss) raised in recirculating aquaculture systems (RAS) were evaluated for the effect of temperature (10-30 °C) on biomass, geosmin, and 2-methylisoborneol (MIB) production and cellular activity. Cultures of these isolates were monitored over 7 days by measuring culture dry weight, geosmin, and MIB production using solid-phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS), and ATP production via a luminometer. Compared to the other isolates, S. luridiscabiei had significantly (P < 0.05) higher biomass (8.17 ± 0.35 mg/mL) at 15 °C (water temperature in the RAS) after 7 days incubation. In addition, S. luridiscabiei produced significantly (P < 0.05) higher geosmin (69,976 ± 15,733 ng/L) at 15 °C. At 25 °C and 30 °C, S. albidoflavus produced significantly (P < 0.05) higher geosmin (182,074 ± 60,272 ng/L and 399,991 ± 102,262 ng/L, respectively). All isolates produced MIB at 15 °C, but S. luridiscabiei produced significantly (P < 0.05) higher MIB (97,143 ± 28,972 ng/L) and ATP after 7 days. Therefore, S. luridiscabiei appears to be a likely contributor of geosmin and MIB in the RAS.

Nocardia veterana: disseminated infection with urinary tract infection

Nocardia spp. are a group of aerobic actinomycetes widely distributed in soil, and associated with severe opportunistic infections, essentially pulmonary infections. We report the first case of disseminated infection associated with urinary tract infection caused by Nocardia veterana. The diagnosis was difficult; despite the presence of pulmonary nodules, the lung biopsies remained negative while only one aerobic blood culture and the urine culture were positive for N. veterana, identified after a 16S rDNA gene sequence analysis. Few cases of clinical importance due to N. veterana have been published since its characterization. The bacteriological diagnosis of nocardiosis can be difficult to establish because of the delayed growth and the specific techniques that are required. This case illustrates the necessity of performing specific investigations in immunocompromised patients who present with infectious disease because the severity of this infection requires early diagnosis and quick initiation of appropriate antibiotic therapy.

[Lung cavities caused by Nocardia cyriacigeorgica in an immunosuppressed boy]

The identification of nodules and/or cavitations in the chest X-ray of a chronically or acute ill patient will rise the suspicion of tuberculosis. However, it is important to be aware of pulmonary nocardiosis as a rare but important differential diagnosis, especially in case of no hilar adenitis. In this case report, we describe a six-year-old boy receiving prednisolone due to nephrotic syndrome, who developed pneumothorax because of pulmonal nocardiosis. The prognosis is good in case of early diagnosis and antibiotic treatment.

Insights into the microbial degradation of rubber and gutta-percha by analysis of the complete genome of Nocardia nova SH22a

The complete genome sequence of Nocardia nova SH22a was determined in light of the remarkable ability of rubber and gutta-percha (GP) degradation of this strain. The genome consists of a circular chromosome of 8,348,532 bp with a G+C content of 67.77% and 7,583 predicted protein-encoding genes. Functions were assigned to 72.45% of the coding sequences. Among them, a large number of genes probably involved in the metabolism of xenobiotics and hardly degradable compounds, as well as genes that participate in the synthesis of polyketide- and/or nonribosomal peptide-type secondary metabolites, were detected. Based on in silico analyses and experimental studies, such as transposon mutagenesis and directed gene deletion studies, the pathways of rubber and GP degradation were proposed and the relationship between both pathways was unraveled. The genes involved include, inter alia, genes participating in cell envelope synthesis (long-chain-fatty-acid-AMP ligase and arabinofuranosyltransferase), β-oxidation (α-methylacyl-coenzyme A [α-methylacyl-CoA] racemase), propionate catabolism (acyl-CoA carboxylase), gluconeogenesis (phosphoenolpyruvate carboxykinase), and transmembrane substrate uptake (Mce [mammalian cell entry] transporter). This study not only improves our insights into the mechanism of microbial degradation of rubber and GP but also expands our knowledge of the genus Nocardia regarding metabolic diversity.

Long-term treatment of persistent disseminated Nocardia cyriacigeorgica infection

In this paper a disseminated persistent Nocardia cyriacigeorgica infection in an immunocompetent patient is described. The patient's long-term treatment, as well as its implications for managing similar cases in the future, is emphasized. Presenting with high fever, multiple nodules, and ulcerative cutaneous lesions of body sites, the patient was treated with various antimicrobials. Under combined therapy, empyema and arthritis, leading to disseminated nocardiosis, were seen. The overall treatment course was 28 months. It can be concluded that the choice of the antibiotics and optimal duration of treatment are uncertain; therefore the treatment of nocardiosis requires expertise.

Pulmonary nocardiosis associated with cerebral abscess successfully treated by co-trimoxazole: a case report

Nocardiosis is an acute or chronic infectious disease caused by the soil-borne filamentous bacteria belonging to the genus Nocardia. The organisms opportunistically infect both immunocompromised and immunocompetent individuals. The lungs are the primary site of infection and brain abscess is, by far, the most common complication following nocardial metastasis from pulmonary lesions. Although surgical intervention must always be considered in the treatment of nocardial brain abscess, it can obviously be cured by antibiotic therapy alone. This report describes a case infected by Nocardia cyriacigeorgica. Identification of the infectious agent was achieved by conventional and semi-nested PCR techniques. A 55-year-old woman with fever was referred to the infect disclinic of Imam Khomeini hospital in Tehran and was hospitalized after clinical assessment. She was a kidney transplant recipient for 4 years and was taking immunosuppressive treatment including azathioprine and methylprednisolone. Follow-up of the patient by CT scan revealed pulmonary infection and cerebral lesions. Specimens of the brain lesions contained filamentous bacteria. The patient received a combination of co-trimoxazole and ceftriaxone and brain abscesses as well as lung inflammation disappeared gradually during the course of antibiotic therapy within 3 months. The patient was discharged from the hospital after 2 months of therapy.

Lung Nocardia elegans infection diagnosed on matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS)

A 73-year-old man with adultonset Still's disease developed a high fever, coughing, dyspnea and bloody sputum and was therefore admitted to our hospital. Thoracic X-ray and CT scans revealed oval lesions in the bilateral lungs. A bacterial isolate from the sputum was identified to be Nocardia elegans (N. elegans) on comparative 16S rRNA gene sequencing and Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS). The patient recovered following treatment with imipenem/cilastatin and amikacin. To the best of our knowledge, this is the first case of nocardiosis caused by N. elegans identified on MALDI-TOF MS.

Primary brain abscess caused by Nocardia otitidiscaviarum

Diagnosing primary cerebral nocardiosis is difficult. This case report describes a 79-year-old immunocompetent Japanese woman with a primary brain abscess caused by Nocardia otitidiscaviarum (IFM 11321) and reviews the findings of 11 previous patients with N. otitidiscaviarum-induced brain abscesses. Four patients survived, including ours. Beta-lactams were not effective in our patient, and the diagnosis required a pathologic analysis of the surgical specimen. Sulfamethoxazole/trimethoprim (ST) was administered to the patient. On antibiotic susceptibility testing, N. otitidiscaviarum (IFM11321) was found to be resistant to amoxicillin-clavulanic acid, ceftriaxone, cefotaxime, cefepime, imipenem and clarithromycin, but sensitive to amikacin, gentamicin, ST and linezolid. Antimicrobial susceptibility patterns differ among Nocardia species, making species identification important for treatment. Patients with suspected Nocardia infection should therefore be treated empirically with ST and/or amikacin and considered for surgical management.

Nocardia yamanashiensis in an immunocompromised patient presenting as an indurated nodule on the dorsal hand

BACKGROUND

Nocardia are ubiquitous, aerobic, gram-positive actinomycetes. Nocardiosis typically occurs in immunocompromised patients, although immunocompetent individuals can also be affected.

PURPOSE

The purpose of this case study is to review the clinical characteristics and treatments of a unique form of cutaneous nocardiosis.

MATERIALS AND METHODS

We retrospectively reviewed the medical literature using PubMed, searching the terms cutaneous, host, immunocompromised, Nocardia, primary, yamanashiensis. Patient reports and previous reviews of the subject were critically assessed and the salient features are presented.

RESULTS

Cutaneous nocardiosis typically presents as pustular nodules and the lesions may progress to become abscesses, cellulitis, granulomas or keloid-like tumors. N. brasiliensis is the predominant species involved in primary cutaneous nocardiosis; other common Nocardia species involved in human disease are N. farcinica, N. abscessus, N. cyriacigeorgica, and N. nova. Only two individuals (including the patient presented here) with primary cutaneous infection by N. yamanashiensis have been described in the literature; a third clinical isolate was recovered from a lung biopsy.

CONCLUSION

Nocardia yamanashiensis is a rare clinical form of primary cutaneous nocardiosis. 16S ribosomal gene sequencing, as well as Gram stain and modified Fite acid-fast stain, play a vital role in identifying this clinical variant.

Molecular identification of nocardia isolates from clinical samples and an overview of human nocardiosis in Brazil

BACKGROUND

Nocardia sp. causes a variety of clinical presentations. The incidence of nocardiosis varies geographically according to several factors, such as the prevalence of HIV infections, transplants, neoplastic and rheumatic diseases, as well as climate, socio-economic conditions and laboratory procedures for Nocardia detection and identification. In Brazil the paucity of clinical reports of Nocardia infections suggests that this genus may be underestimated as a cause of human diseases and/or either neglected or misidentified in laboratory specimens. Accurate identification of Nocardia species has become increasingly important for clinical and epidemiological investigations. In this study, seven clinical Nocardia isolates were identified by multilocus sequence analysis (MLSA) and their antimicrobial susceptibility was also determined. Most Nocardia isolates were associated to pulmonary disease.

METHODOLOGY/PRINCIPAL FINDINGS

The majority of Brazilian human isolates in cases reported in literature were identified as Nocardia sp. Molecular characterization was used for species identification of Nocardia nova, Nocardia cyriacigeorgica, Nocardia asiatica and Nocardia exalbida/gamkensis. Data indicated that molecular analysis provided a different Nocardia speciation than the initial biochemical identification for most Brazilian isolates. All Nocardia isolates showed susceptibility to trimethoprim-sulfamethoxazole, the antimicrobial of choice in the treatment nocardiosis. N. nova isolated from different clinical specimens from one patient showed identical antimicrobial susceptibility patterns and two distinct clones.

CONCLUSIONS/SIGNIFICANCE

Although Brazil is the world's fifth-largest country in terms of land mass and population, pulmonary, extrapulmonary and systemic forms of nocardiosis were reported in only 6 of the 26 Brazilian states from 1970 to 2013. A least 33.8% of these 46 cases of nocardiosis proved fatal. Interestingly, coinfection by two clones may occur in patients presenting nocardiosis. Nocardia infection may be more common throughout the Brazilian territory and in other developing tropical countries than is currently recognized and MLSA should be used more extensively as an effective method for Nocardia identification.

[Thoracic nocardiosis with thoracic manifestations in two immunocompetent patients]

Nocardiosis is a rare infectious disease caused by bacteria of the genus nocardia, which causes considerable morbidity and mortality. We report two unusual cases of nocardiosis in young, immunocompetent patients; the first case involved a nocardia farcinica pulmonary and chest-wall infection, while the second was an anterior mediastinal nocardia asiaticum infection mimicking a mediastinal tumor. These cases reflect the need for a broad differential diagnosis during exploration of thoracic findings, white the potentially ambiguous presentation of nocardiosis must be considered.