Overlapping infections of Mycobacterium canariasense and Nocardia farcinica in an immunocompetent patient: A case report

BACKGROUND

Infections by non-tuberculous mycobacteria (NTM) have become more common in recent years. Mycobacterium canariasense (M. canariasense) was first reported as an opportunistic pathogen in 2004, but there have been very few case reports since then. Nocardia is a genus of aerobic and Gram-positive bacilli, and these species are also opportunistic pathogens and in the Mycobacteriales order. Conventional methods for diagnosis of NTM are inefficient. Metagenomic next-generation sequencing (mNGS) can rapidly detect many pathogenic microorganisms, even rare species. Most NTM and Nocardia infections occur in immunocompromised patients with atypical clinical symptoms. There are no previous reports of infection by M. canariasense and Nocardia farcinica (N. farcinica), especially in immunocompetent patients. This case report describes an immunocompetent 52-year-old woman who had overlapping infections of M. canariasense, N. farcinica, and Candida parapsilosis (C. parapsilosis) based on mNGS.

CASE SUMMARY

A 52-year-old woman presented with a productive cough and chest pain for 2 wk, and recurrent episodes of moderate-grade fever for 1 wk. She received antibiotics for 1 wk at a local hospital, and experienced defervescence, but the productive cough and chest pain persisted. We collected samples of a lung lesion and alveolar lavage fluid for mNGS. The lung tissue was positive for M. canariasense, N. farcinica, and C. parapsilosis, and the alveolar lavage fluid was positive for M. canariasense. The diagnosis was pneumonia, and application of appropriate antibiotic therapy cured the patient.

CONCLUSION

Etiological diagnosis is critical for patients with infectious diseases. mNGS can identify rare and novel pathogens, and does not require a priori knowledge.

Infectious Diarrhea Caused by Nocardia farcinica in a 19-Month-Old Child

Background

Nocardia farcinica, a pathogen known for its strong pathogenicity, is frequently implicated in skin, central nervous system, and lung infections among immunosuppressed hosts, while intestinal nocardiosis is rare. We report the case of infectious diarrhea caused by N. farcinica in a child.

Case Presentation

A 19-month-old female child was admitted to the hospital with fever and diarrhea after the consumption of oranges. The etiological agent responsible for the diarrhea was identified through the examination of fecal smears using weak acid-fast staining and conducting fecal cultures. Whole-genome sequencing was employed to analyze the causative gene. Subsequent to a 5-day treatment regimen with amoxicillin-clavulanate at a dosage of 30 mg/kg every 12 hours, the child's condition improved significantly, leading to an uncomplicated discharge.

Conclusion

This case illustrates the presence of intestine virulence factors in N. farcinica capable of causing diarrhea. The utilization of weak acid-fast staining in the examination of fecal smears is crucial for the accurate diagnosis of infectious diarrhea caused by Nocardia spp.

Exploring Nocardia's ecological spectrum and novel therapeutic frontiers through whole-genome sequencing: unraveling drug resistance and virulence factors

Nocardia farcinica is the leading pathogen responsible for nocardiosis, a life-threatening infection primarily affecting immunocompromised patients. In this study, the genomic sequence of a clinically isolated N. farcinica sample was sequenced. Subsequently, the assembled genome was annotated to identify antimicrobial resistance and virulence genes, as well as plasmid and prophages. The analysis of the entire genome size was 6,021,225 bp, with a GC content of 70.78% and consists of 103 contigs and N50 values of 292,531 bp. The genome analysis revealed the presence of several antimicrobial resistance genes, including RbpA, mtrA, FAR-1, blaFAR-1, blaFAR-1_1, and rox. In addition, virulence genes such as relA, icl, and mbtH were also detected. The present study signifies that N. farcinica genome is pivotal for the understanding of antimicrobial resistance and virulence genes is crucial for comprehending resistance mechanism, and developing effective strategies to combat bacterial infections effectively, especially adhesins and toxins. This study aids in identifying crucial drug targets for combating multidrug-resistant N. farcinica in the future.

Nocardia farcinica infection presenting as a solitary bronchial neoplasm in an immunocompetent adult: a case report

Nocardia species are gram-positive, acid-fast, saprophytic, aerobic bacilli, predominantly resulting in opportunistic infections in immunocompromised individuals. Here, we reported a case of Nocardia infection in a 27-year-old woman with normal immunocompetence, who presented as a solitary neoplasm in the left principal bronchus with a chief complaint of postural dyspnea. By electrotomy via bronchoscopy, the neoplasm was successfully removed, and it was further identified as Nocardia farcinica by metagenomic next-generation sequencing.

Nocardia farcinica abortion in a goat

A female goat fetus was received by the Colorado State University-Veterinary Diagnostic Laboratory following an isolated abortion of twins by a reportedly healthy doe. Postmortem examination did not reveal any gross abnormalities. Histologic evaluation revealed pyogranulomatous and necrotizing bronchopneumonia with intracellular and extracellular gram-positive and non-acid-fast filamentous bacilli. Aerobic culture of the stomach contents and pooled lung and liver tissue yielded light growth of Nocardia sp., which was identified by MALDI-TOF MS and 16s rDNA sequencing as Nocardia farcinica.

The Effect of Cryopreservation on the Survival of Nocardia farcinica and Yersinia pestis vaccine strains

Pathogenic microorganisms are valuable biological resources, closely related to biosecurity, human health, environmental protection, and renewable energy. It is very important to properly preserve the microbial resources by methods to maintain the purity, viability, and integrity, and to avoid prolonged degradation. The present work aims to explore the cryopreservation technology of Nocardia farcinica (Gram-positive bacteria) and Yersinia pestis vaccine strains (Gram-negative bacteria). The effects of cryoprotectants (CPAs), freezing temperature, and freeze-thaw cycles on the two bacteria in the cryopreservation process were studied. The results showed that the addition of CPAs (glycerol, propylene glycol, sucrose, glucose, l-carnitine, l-proline, and skim milk) significantly enhanced the survival rates of the N. farcinica and Y. pestis vaccine strains. However, high concentrations of CPAs can produce biochemical toxicity in the two pathogens. The utilization of composite CPAs not only reduced the toxicity but also improved the survival rates of samples during cryopreservation. The optimal composite CPA for N. farcinica is 0.292 M sucrose, 0.62 M l-carnitine, and 2.82 M glycerol. The optimal composite CPA for Y. pestis is 0.62 M l-carnitine, 8.46 M glycerin, and 0.292 M sucrose. The results showed that the quality of the strains stored at -80°C and -196°C was better. For the case of freeze-thaw cycles, the two pathogens have different degrees of reduction, and the survival rate of Y. pestis decreased more than that of N. farcinica. The uniform distribution of bacteria in CPAs can form uniform nucleation sites in the solution system, which is beneficial to the cryopreservation of strains, as can be seen from the experimental results from a differential scanning calorimeter. This study may provide a reference for better preservation of precious natural biological resources of pathogenic microorganisms.

Evaluation of BACTEC MGIT 960 system for recovery of Nocardia from clinical specimens

Nocardia spp. is an aerobic Gram-positive bacillus responsible for nocardiosis. Herein, we performed a retrospective study to evaluate the performance of BACTEC MGIT 960 system, in comparison with smear microscopy and blood agar plate (BAP) culture, to recover Nocardia from different clinical specimens. Furthermore, the inhibitory effect of antibiotics contained in MGIT 960 tube on Nocardia was also evaluated. The sensitivities for Nocardia recovery using smear microscopy, BAP culture, and MGIT 960 were 39.4% (54/137), 46.1% (99/215), and 81.3% (156/192), respectively. N. farcinica was the most detected species (60.4%, 136/225). In MGIT 960-recovered Nocardia strains, N. farcinica accounted for 76.9%. Furthermore, trimethoprim in MGIT 960 tube inhibited less N. farcinica growth than that of other Nocardia species, partially explaining why MGIT 960 recovered more N. farcinica from sputa. The current study demonstrated that MGIT 960 could recover Nocardia strains from heavily-contaminated samples if its components and antibiotics are redesigned.

Disseminated Nocardia farcinica Infection and Treatment Response on F-18 Fludeoxyglucose Positron Emission Tomography Computed Tomography

We report a rare case of nocardiosis with increased F-18 Fludeoxyglucose (F-18 FDG) uptake in widespread abscess foci of Nocardia farcinica infection in an immunocompromised patient on positron emission tomography computed tomography (PET/CT) imaging. A relatively infrequent cause of nocardiosis, N. farcinica is an opportunistic infection that may present with clinically aggressive disseminated disease. Whole-body F-18 FDG-PET/CT allows identifying the extent of disease, as well as monitoring response to therapy in patients with nocardiosis especially the disseminated form.

Otomastoiditis Caused by Nocardia Farcinica: A Case Report and Literature Review

Nocardia farcinica usually infects people with impaired immune status and usually manifests in the lungs. Otomastoiditis caused by Nocardia infection is extremely rare, with only 4 cases reported to date. This report describes a case of otomastoid N. farcinica infection in an immunocompetent patient. The case was a 10-month-old immunocompetent infant who presented with an approximately 3-month history of right ear discharge for which treatment with various antibiotics had not resulted in significant improvement. Multiple cultures of secretions and pathologic examination failed to identify the causative organism. The patient then underwent right mastoidectomy. Finally, metagenomic next-generation sequencing identified the pathogen to be N. farcinica. The patient was infection-free at the 6-month follow-up but had developed labyrinthitis ossificans. Otomastoid Nocardia infection has characteristic clinical features, namely, formation of a large amount of granulation tissue and coexistence of bone destruction and new bone formation. Traditionally, Nocardia is challenging to diagnose. Metagenomic next-generation sequencing of lesions is helpful. Complete local debridement and free drainage are key to treatment.

Encephalic nocardiosis after mild COVID-19: A case report

The COVID-19 pandemic and the associated post-acute sequelae of COVID-19 (PASC) have led to the identification of a complex disease phenotype that is associated with important changes in the immune system. Herein, we describe a unique case of Nocardia farcinica cerebral abscess in an individual with sudden immunodeficiency several months after mild COVID-19. Intravenous Bactrim and Imipenem were prescribed for 6 weeks. After this, a 12-month course of Bactrim and Clavulin was prescribed to be taken orally, given the N. farcinica infection at the level of the central nervous system. This case report highlights the need for future research into the pathophysiology of COVID-19 and PASC immune dysregulation in convalescent individuals. It also draws attention to the need for timely consideration of opportunistic infections in patients with a history of COVID-19.

Nocardia farcinica Pneumonia with Sepsis and a Bronchial Neoplasm in a Healthy Patient: A Case Report

There are few reports on sepsis caused by infection with Nocardia in people with normal immune function, and there is no report on bronchial tumor caused by Nocardia. This paper describes a case of Nocardia farcinica pneumonia with sepsis and a bronchial neoplasm in a healthy patient.

Disseminated Nocardiosis Caused by Nocardia farcinica in Two Puppy Siblings

Systemic nocardiosis due to Nocardia farcinica has not been reported in canine outbreaks. Two 14-week-old female Dogue de Bordeaux siblings presented with fever and severe, acute onset limb lameness; traumatic lesions with evidence of infection were identified over the lame limbs of both dogs. The patients were euthanised owing to lack of therapeutic response and rapid escalation to systemic infection with central nervous system manifestations. The post-mortem changes consisted of multiple disseminated abscesses, mainly affecting the skin and subcutis at the limb traumatic injuries, local and hilar lymph nodes, lung, kidney and brain. Bacterial culture and identification via MALDI-TOF and 16S rRNA sequencing revealed Nocardia farcinica from several of these sites in both dogs. Clinical significance of the isolate was supported by cytology of the post-mortem organs' impression smears showing numerous branching filamentous bacteria associated with inflammation. The organism displayed marked multidrug-resistance. No history of immunosuppression was available, and immunohistochemistry ruled out viral pathogens as canine distemper and parvovirus. N. farcinica should be considered as a potential differential cause of sudden lameness and systemic infection in dogs with traumatic skin lesions over the limbs. This is the first reported small-scale outbreak of systemic nocardiosis in dogs due to N. farcinica.

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

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

Characterization of Latex-Clearing Protein and Aldehyde Dehydrogenases Involved in the Utilization of poly(cis-1,4-isoprene) by Nocardia farcinica NBRC 15532

Microbial degradation of natural rubber and synthetic poly(cis-1,4-isoprene) is expected to become an alternative treatment system for waste from poly(cis-1,4-isoprene) products including scrap tires. Nocardia farcinica NBRC 15,532, a gram-positive rubber-degrading bacterium, can utilize poly(cis-1,4-isoprene) as the sole source of carbon and energy to produce oligo-isoprene metabolites containing aldehyde and keto end groups. A homology-based search of the genome revealed a gene encoding a latex-clearing protein (Lcp). Gene disruption analysis indicated that this gene is essential for the utilization of poly(cis-1,4-isoprene) in this strain. Further analysis of the genome sequence identified aldehyde dehydrogenase (ALDH) genes as potential candidates for oxidative degradation of oligo-isoprene aldehydes. Based on the enzymatic activity of the ALDH candidates, NF2_RS14000 and NF2_RS14385 may be involved in the degradation of oligo-isoprene aldehydes. Analysis of the reaction products revealed that these ALDHs oxidized tri- to penta-isoprene aldehydes, which were generated by the reaction of Lcp. Based on the inability of ALDH gene deletion mutants, we concluded that NF2_RS14000 is mainly involved in the utilization of poly(cis-1,4-isoprene) and the oxidative degradation of oligo-isoprene aldehydes in Nocardia farcinica NBRC 15,532.

Nocardia farcinica pituitary abscess in an immunocompetent patient: illustrative case

BACKGROUND

Pituitary abscess is a rare clinical entity, typically precipitated by Staphylococcus, Pseudomonas, or Aspergillus infection. Although Nocardia species–associated central nervous system abscesses have been documented in immunocompromised patients, no case of Nocardia pituitary abscesses has been previously reported.

OBSERVATIONS

A 44-year-old man presented with hemoptysis and was found to have a cavitary right lung nodule, which was presumed histoplasmosis, prompting antifungal treatment. Several months later, he developed panhypopituitarism. Magnetic resonance imaging identified a pituitary mass, which subsequently underwent transsphenoidal endoscopic biopsy. Infectious workup was negative, and the patient was discharged on intravenous ertapenem therapy. Over several months, he developed progressive headaches, and updated imaging confirmed interval enlargement of the mass with new cavernous sinus invasion. He underwent repeat endoscopic biopsy, which yielded positive cultures for Nocardia farcinica and prompted successful treatment with trimethoprim-sulfamethoxazole and linezolid.

LESSONS

The current study highlights a previously unreported clinical entity, the first pituitary abscess attributable to Nocardia sp. or N. farcinica, which arose in a young, immunocompetent individual. Although rare, atypical infections represent an important component in the differential diagnosis for sellar mass lesions.

A Rare Case of Co-Infection with Nocardia farcinica, Pneumocystis jirovecii, and Aspergillus fumigatus Due to Tooth Extraction in a Mildly Immunosuppressed Patient

We report a case of co-infection with Nocardia farcinica, Pneumocystis jirovecii, and Aspergillus fumigatus due to tooth extraction in a mildly immunosuppressed patient. This patient did not respond well to a meropenem-based regimen, and the number of lesions was significantly reduced after switching to imipenem. The patient's trough concentration was insufficient when using conventional doses of voriconazole for the treatment of pulmonary aspergillosis. After adding omeprazole, the concentration reached standard levels and symptoms improved. The patient eventually made a full recovery.

Disseminated Nocardiosis with Pulmonary Fungus and Secondary Epilepsy: A Case Report

Disseminated nocardiosis is a rare, life-threatening disease that usually found in immunocompromised patients, and Nocardia farcinica is one of the most common causative pathogens. The difficulty in identifying the bacterium and the delay in initiating appropriate therapy often influence the prognosis of patients with disseminated nocardiosis. Here, we present a rare case of disseminated nocardiosis in a 61-year-old female with pulmonary fungus and secondary epilepsy. She received targeted antibiotic therapy and showed a great recovery in clinical symptoms and radiological signs. Disseminated nocardiosis can be easily overlooked due to the absence of characteristic symptoms and limitations of clinical examinations. Given the variability in antibiotic susceptibility patterns, the management of disseminated nocardiosis must be individualized. Therefore, early diagnosis and targeted antibiotic treatment are critical for the prognosis of disseminated nocardiosis.

Prognosis and factors associated with disseminated nocardiosis: a ten-year retrospective multicenter study

OBJECTIVES

Nocardiosis is a rare opportunistic infection that is frequently associated with dissemination (i.e. involvement of several body sites). Identifying the factors associated with Nocardia spp. dissemination may help improving the management of patients with nocardiosis.

METHODS

This 10-year (2010-2020) retrospective multicenter cohort study included adult patients with Nocardia-confirmed infections. The first objective was to determine the factors associated with disseminated nocardiosis. The secondary endpoints were to determine and compare the management and the 12-month overall mortality in patients with localized and disseminated nocardiosis. Univariate and multivariate logistic regression analyses were used.

RESULTS

Nocardia spp. infection was confirmed in 110 patients, of whom 38 (34.5%) had disseminated nocardiosis. In univariate analysis, the factors associated with dissemination were immunosuppressive conditions: having an auto-immune disease and receiving high-dose corticosteroid (31.5% vs 8.3%, P=0.003 and 52.6% vs 26.3%, P=0.007, respectively). Absolute lymphocyte count <1G/L at diagnosis was the only biomarker associated with dissemination (57.2% vs 26.3%, P=0.007). Nocardia farcinica was not only the most frequent species identified in patient specimens (n=22, 20%) but was also associated with a higher rate of dissemination (36.8% vs 11.1%, P=0.002). Multivariate analysis confirmed the association between auto-immune diseases, lymphopenia, N. farcinica species and the higher rate of dissemination. Even though patients with disseminated nocardiosis were treated longer and more often with an antibiotic combination therapy, their 12-month overall mortality was significantly higher than that of patients with localized nocardiosis (36.8% vs 18%).

CONCLUSIONS

Dissemination of Nocardia spp. is favoured by auto-immune diseases, lymphopenia, and infection with N. farcinica.

Estradiol Aggravate Nocardia farcinica Infections in Mice

Males are generally more susceptible to Nocardia infection than females, with a male-to-female ratio of 2 and higher clinical disease. 17β-Estradiol has been implicated in affecting the sex-based gap by inhibiting the growth of N. brasiliensis in experiments, but the underlying mechanisms have not yet been fully clarified. In the present study, however, we report increased severity in N. farcinica IFM 10152-infected female mice compared with male mice with increased mortality, elevated lung bacterial loads and an exaggerated pulmonary inflammatory response, which was mimicked in ovariectomized female mice supplemented with E2. Similarly, the overwhelming increase in bacterial loads was also evident in E2-treated host cells, which were associated with downregulating the phosphorylation level of the MAPK pathway by binding the estrogen receptor. We conclude that although there are more clinical cases of Nocardia infection in males, estrogen promotes the survival of the bacteria, which leads to aggravated inflammation in females. Our data emphasize the need to include and separately analyze both sexes in future studies of Nocardia to understand the sex differences in immune responses and disease pathogenesis.

Brain Abscess Caused by Nocardia farcinica and Diagnosed by Metagenomic Next-Generation Sequencing: A Case Report

Background

Brain abscesses caused by Nocardia farcinica are rare and difficult to diagnose. Conventional methods for diagnosing Nocardia species include blood culture, microscopy, and tissue slice, but the performance is not satisfied. We report a case of brain abscess due to N. farcinica diagnosed by metagenomic next-generation sequencing (mNGS).

Case Presentation

We report a case of a 58-year-old man with brain abscess caused by N. farcinica. The patient had a history of pemphigus and required long-term methylprednisolone administration. No pathogen was detected in blood culture, cerebrospinal fluid (CSF) culture, and fast-acid staining. mNGS identified N. farcinica in the CSF. The symptoms and signs of the patient were significantly improved after changing the antibiotics accordingly to sensitive antibiotics.

Conclusion

Metagenomic next-generation sequencing (mNGS) is helpful for early diagnosis and subsequent treatment of Nocardia-associated meningitis and encephalitis, avoiding brain surgery. Early and accurate diagnosis and prompt antibiotic treatment reduced its mortality.

Disseminated Nocardia farcinica involves the spinal cord: a case report and review of the literature

Background

Nocardia is a relatively rare opportunistic pathogenic bacteria group, commonly seen in patients with immunocompromised or defective immune system. It can affect multiple organs of the body and cause disseminated infection, among which most occurs in the lung, secondly in the nervous system, soft tissues, rare in the spinal cord and pituitary. No case has been reported involving lung, spinal cord, skin and pituitary gland at the same time.

Case presentation

We report a 55-year-old female with Nocardia infection involving the lung, skin, spinal cord, and pituitary gland. The patient underwent a full set of imaging examinations and showed typical imaging findings. Chest computed tomography (CT) showed multiple nodules with cavities in the lungs. The magnetic resonance imaging (MRI) of the vertebral body showed abnormal signal of the entire spinal cord with cavity formation and ring enhancement. The subcutaneous nodules of the abdomen were punctured under ultrasound. Through the etiological tissue culture of subcutaneous nodules and the second generation sequencing of cerebrospinal fluid, the diagnosis was finally confirmed.

Conclusion

Disseminated Nocardiosis is an uncommon disease. This article will report a rare case of disseminated Nocardiosis simultaneously involving the lung, spinal cord, subcutaneous soft tissue and pituitary gland, especially with neuropathy as the initial symptom. Imaging is helpful for the early diagnosis of the disease and pathological and microbiological examinations are helpful for its confirming.

Nocardia farcinica Brain Abscess in a Multiple Myeloma Patient Treated with Proteasome Inhibitor: A Case Report and Review of the Literature

Nocardia brain abscess is relatively rare, accounting for about 1–2% of all brain abscesses, and its mortality rate is three times higher than of other types of bacterial brain abscesses; thus, early diagnosis and treatment are essential. Nocardia brain abscess generally occurs in immunodeficient patients. We report a case of Nocardia farcinica brain abscess in a multiple myeloma patient treated with proteasome inhibitor (bortezomib and ixazomib), cyclophosphamide, and corticosteroid. The patient was treated with ceftriaxone and trimethoprim-sulfamethoxazole, together with drainage of the brain abscess. Regular brain MRI follow-ups showed that intracranial lesions were gradually absorbed and improved.

Misdiagnosed tuberculosis being corrected as Nocardia farcinica infection by metagenomic sequencing: a case report

Background

Disseminated nocardiosis is liable to be misdiagnosed owing to the non-specific clinical manifestations and laboratory/imaging findings. Metagenomic next-generation sequencing (mNGS) is a culture-independent and rapid method for direct identification of all microorganisms in clinical specimens.

Case presentation

A 72-year-old man was admitted to our hospital on February 20, 2019 with a history of recurrent cough, expectoration, fever, and diarrhea since 1 month, and unconsciousness since 1 week. Contrast-enhanced magnetic resonance imaging of head showed multiple lesions in the bilateral cerebral hemispheres, brainstem, and cerebellar hemispheres. The presumptive diagnosis was disseminated tuberculosis, although all tests for mycobacterium were negative. However, the patient did not benefit from antituberculosis treatment. Repeat MRI showed multiple abnormal signals in the brain and progression of meningeal thickening. Cerebrospinal fluid and bronchoalveolar lavage fluid specimens were subsequently sent for PMSeq metagenomics sequencing; the results indicated Nocardia. farcinica as the predominant pathogen. The anti-TB treatment was stopped and the patient was prescribed sulphamethoxazole in combination with linezolid and meropenem for nocardiosis. He showed gradual neurological improvement and was transferred to Huashan Hospital. He was discharged from the hospital on April 19, 2019, but died of persistent diarrhea on May 26, 2019.

Conclusions

Patients with suspected nocardiosis do not always respond to conventional treatment; therefore, mNGS can facilitate diagnosis and timely treatment decision-making.

A case report of brain abscess caused by Nocardia farcinica

Background

Brain abscess due to the Nocardia genus is rarely reported and it is usually found in immunocompromised patients. Treatment of Nocardia brain abscess is troublesome and requires consideration of the severity of the underlying systemic disease. The difficulties in identifying the bacterium and the frequent delay in initiating adequate therapy often influence the prognosis of patients.

Case presentation

Here, we report a rare case of brain abscess caused by Nocardia farcinica. The patient’s medical history was complicated: he was hospitalized several times, but no pathogens were found. At last, bacteria were found in the culture of brain abscess puncture fluid; the colony was identified as Nocardia farcinica by mass spectrometry. Targeted antibiotic treatment was implemented, brain abscess tended to alleviate, but the patient eventually developed fungal pneumonia and died of acute respiratory distress syndrome (ARDS).

Conclusion

Brain abscess caused by Nocardia farcinica can appear in non-immunocompromised individuals. Early diagnosis, reasonable surgical intervention, and targeted antibiotic treatment are critical for Nocardia brain abscess treatment. In the treatment of Nocardia brain abscess, attention should paid be to the changes in patients’ immunity and infection with other pathogens, especially fungi, avoided.

Rare isolation of Nocardia farcinica in a fatal case of disseminated nocardiosis in an immunocompetent person

Nocardia species can cause various types of infections including, pulmonary, cutaneous, disseminated & CNS diseases. Here, we report a case of disseminated nocardiosis, probably secondary to pulmonary foci, in an immunocompetent patient. Blood culture showed gram-positive bacilli, which on culture grew aerial chalky white growth showed the acid-fast, gram-positive filamentous bacteria. The culture was identified as Nocardia farcinica by MALDI-TOF. Unfortunately, the patient succumbed to the infection on the 5th day after admission.

Post-traumatic exogenous endophthalmitis caused by Nocardia farcinica

A case report of post-traumatic exogenous endophthalmitis caused by Nocardia farcinica, including treatment procedures, microbiology examination, and systemic medications. A 23-year-old male suffered a penetrating corneal injury that was treated with sutures. On the thirteenth day after the final suture was removed, an anterior uveitis developed and progressed to whitish, plump, nodular, and tufted exudates within the anterior chamber over the next 10 days; this led to an indication for intraocular surgery. Anterior chamber lavage and resection of solid fibrinous exudates (using a vitrectomy knife) for a complete microbiological examination were performed. Nocardia farcinica was identified. Systemic medications were chosen according to sensitivity, and a fixed combination of sulfamethoxazole 400 mg/trimethoprim 80 mg was administered long-term (months). In this case, accurate, early detection of an atypical infectious agent and determination of its sensitivity to antibiotic treatment enabled effective treatment that achieved the best functional and anatomical results under the circumstances.

Nocardia farcinica cerebral abscess: A systematic review of treatment strategies

PURPOSE

Nocardia farcinica is an opportunistic pathogen causing mainly pneumonia in immunocompromised patients, complicated in almost one-third of the cases by a thick-walled multiloculated cerebral abscess which induces significant morbidity and mortality. This review aims to assess the optimal treatment strategy for N. farcinica cerebral abscess.

METHODS

Report of a case. Medline database was used to conduct a systematic review from inception to January 2020 looking for English-language articles focused on N. farcinica cerebral abscess, in accordance with the PRISMA guidelines.

RESULTS

The research yielded 54 articles for a total of 58 patients. N. farcinica cerebral abscess displayed three different neuroimaging patterns: a single multiloculated abscess in half of the cases, multiple cerebral abscesses, or a small paraventricular abscess with meningitis. The patients who benefited from surgical excision of the abscess showed a trend towards a lower risk of surgical revision (8% versus 31%, P=0.06) and a lower mortality rate (8% versus 23%, P=0.18) than patients who benefited from needle aspiration. Twenty-two percent of the patients benefited from microbiological documentation from another site with a mortality rate of 23%.

CONCLUSION

Urgent multimodal MRI is necessary in face with clinical suspicion of cerebral nocardiosis. In case of single or multiple small cerebral abscesses, microbiological documentation can be obtained with puncture of pseudotumoral visceral lesions. In case of large or symptomatic cerebral abscess, an aggressive surgical excision seems a reliable option and can be preferred over needle aspiration. Long-term antibiotic therapy with cotrimoxazole is necessary thereafter.

Idiopathic thrombocytopenic purpura with brain abscess caused by Nocardia farcinica diagnosed using metagenomics next-generation sequencing of the cerebrospinal fluid: a case report

BACKGROUND

Brain abscesses caused by Nocardia farcinica are rare, and mostly occur in immunocompromised individuals. Rapid and accurate diagnosis of nocardiosis is challenging. Due to the inadequate performance of conventional diagnostic methods for Nocardia infection, metagenomics next-generation sequencing (mNGS) of cerebrospinal fluid (CSF) has the potential to improve the diagnosis intracranial nocardiosis.

CASE PRESENTATION

We report a case of 50-year-old man with brain abscess caused by Nocardia farcinica. The patient had a idiopathic thrombocytopenic purpura complication that required long-term methylprednisolone administration. His chest image showed multiple lesions, which had been misdiagnosed as lung cancer, and his head image showed multiple intracranial metastases. No pathogen was detected in routine examinations including blood culture, sputum culture and traditional culture methods of cerebrospinal fluid. In order to accurately identify the pathogen, mNGS was used to detect Nocardia in CSF. Although the patient's condition improved after using sensitive antibiotics, he transferred to the local hospital for treatment because of many complicated diseases and family financial limitations.

CONCLUSION

This case highlights the value of mNGS in the diagnosis of Nocardia brain abscess, and emphasizes the inadequate sensitivity of conventional diagnostic methods for Nocardia infection. Using mNGS can facilitate early and accurate detection of Norcadia-associated of meningitis in immunocompromised patients, thereby reducing unnecessary use of antibiotics and reducing mortality of the disease.

Primary Cutaneous Nocardiosis Due to Nocardia Farcinica: A Case Report of an Often Overlooked Infection

Primary cutaneous nocardiosis by Nocardia farcinica is exceedingly rare. Only six cases have been reported from PubMed in the past 15 years. We encounter such a case in a 55-year-old man receiving long-term steroid and cyclophosphamide. Owing to no characteristic symptoms, the disease can be so easily overlooked and causes fatal consequences. Therefore, we herein discuss common features of primary cutaneous nocardiosis by Nocardia farcinica that remind clinicians considering it.

[Antibiotic analysis and whole genome sequencing of two nocardia farcinica strains causing joint infection]

Objective: To analyze the molecular characteristics and antibiotic susceptibility of two strains of Nocardia farcinica isolated from patients with joint infection using whole genome sequencing. Methods: Two strains of Nocardia farcinica causing knee-joint infections in two elderly patients were collected in January 2020. Whole genome sequencing was used to determine the nocardia species. Drug sensitivity test was performed using the micro-broth dilution and E-test method according to CLSI M24 guideline. ABRicate was used to analyze drug resistance and virulence genes. Snippy and other bioinformatic tools were used for genomic comparison, and to construct SNP homologous tree. Results: The clinical isolates in this study were both Nocardia farcinica. Antimicrobial susceptibility test showed the isolates were resistant to ceftriaxone, cefepime, cefotaxime and trimethoprim/sulfamethoxazole (TMP/SMX). Imipenem, linezolid and amoxicillin-clavulanic acid showed good activity. Four antibiotic resistance genes including class A β-lactamase gene far-1, RNA polymerase binding protein gene RbpA, multi-drug resistance efflux pump transcription activator gene MtrA and regulatory transcription factor gene vanR-O were identified in the Nocardia farcinica genomes, which conferred resistance to beta-lactams, rifampicin, macrolides and vancomycin respectively. No acquired TMP/SMX resistance genes were identified. There are multiple missense mutations in the dihydrofolate reductase family genes. Four virulence genes of icl, mbtH, phoP, and relA that are homologous to Mycobacterium tuberculosis were found. SNP homologous tree analysis showed the two Nocardia strains were closely related, and there were only ten SNP sites, six compound substitutions and one deletion mutation between them. Conclusions: Whole genome sequencing technology is helpful to explore the molecular characteristics and resistance mechanisms of Nocardia species. Nocardia farcinica has a trend of spreading in China. Resistance to TMP/SMX is worthy of attention. The mutation of genes involved in the metabolic pathway of dihydrofolate might be one of multiple TMP/SMX resistance mechanisms.

Asymptomatic cerebral abscesses after pleuropulmonary Nocardia farcinica infection

We report the case of a 68-year-old man with long-term receipt of steroid therapy who was diagnosed with cerebral abscesses and pulmonary nocardiosis. This patient displayed only respiratory symptoms. Confirmation of Nocardia farcinica species was achieved by specific PCR sequencing of the 16S ribosome RNA in bronchoalveolar lavage cultures. Cerebral magnetic resonance imaging revealed abscesses. Antibiotic therapy with trimethoprim/sulfamethoxazole was prescribed given the results of susceptibility tests and was maintained for 12 months, with no evidence of relapse afterwards.

Nocardiosis Associated with Primary Immunodeficiencies (Nocar-DIP): an International Retrospective Study and Literature Review

PURPOSE

Nocardiosis is a life-threatening infectious disease. We aimed at describing nocardiosis in patients with primary immunodeficiency diseases (PID).

METHODS

This international retrospective cohort included patients with PID and nocardiosis diagnosed and/or published from Jan 1, 2000, to Dec 31, 2016. To identify nocardiosis cases, we analyzed PID databases from the French National Reference Center for PID (Paris, France) and the National Institute of Health (NIH, United States of America) and we performed a literature review on PubMed.

RESULTS

Forty-nine cases of nocardiosis associated with PID were included: median age at diagnosis of nocardiosis was 19 (0-56) years and most cases were observed among chronic granulomatous disease (CGD) patients (87.8%). Median time from symptoms to diagnosis of Nocardia infection was 20 (2-257) days. Most frequent clinical nocardiosis presentation was pneumonia (86.7%). Twelve-month mortality rate was 4.2%, and 11.9% of patients experienced a possible recurrence of infection. Nocardiosis more frequently led to the diagnosis of PID among non-CGD patients than in CGD patients. Non-CGD patients experienced more cerebral nocardiosis and more disseminated infections, but mortality and recurrence rates were similar. Highest incidences of nocardiosis among PID cohorts were observed among CGD patients (0.0057 and 0.0044 cases/patient-year in the USA and in France, respectively), followed by IL-12p40 deficiency.

CONCLUSIONS

Among 49 cases of nocardiosis associated with PID, most patients had CGD and lung involvement. Both mortality and recurrence rates were low.

Nfa34810 Facilitates Nocardia farcinica Invasion of Host Cells and Stimulates Tumor Necrosis Factor Alpha Secretion through Activation of the NF-κB and Mitogen-Activated Protein Kinase Pathways via Toll-Like Receptor 4

The mechanism underlying the pathogenesis of Nocardia is not fully known. The Nfa34810 protein of Nocardia farcinica has been predicted to be a virulence factor. However, relatively little is known regarding the interaction of Nfa34810 with host cells, specifically invasion and innate immune activation. In this study, we aimed to determine the role of recombinant Nfa34810 during infection. We demonstrated that Nfa34810 is an immunodominant protein located in the cell wall.

The mechanism underlying the pathogenesis of Nocardia is not fully known. The Nfa34810 protein of Nocardia farcinica has been predicted to be a virulence factor. However, relatively little is known regarding the interaction of Nfa34810 with host cells, specifically invasion and innate immune activation. In this study, we aimed to determine the role of recombinant Nfa34810 during infection. We demonstrated that Nfa34810 is an immunodominant protein located in the cell wall. Nfa34810 protein was able to facilitate the uptake and internalization of latex beads coated with Nfa34810 protein into HeLa cells. Furthermore, the deletion of the nfa34810 gene in N. farcinica attenuated the ability of the bacteria to infect both HeLa and A549 cells. Moreover, stimulation with Nfa34810 triggered macrophages to produce tumor necrosis factor alpha (TNF-α), and it also activated mitogen-activated protein kinase (MAPK) and nuclear factor κB (NF-κB) signaling pathways by inducing the phosphorylation of ERK1/2, p38, JNK, p65, and AKT in macrophages. Specific inhibitors of ERK1/2, JNK, and NF-κB significantly reduced the expression of TNF-α, which demonstrated that Nfa34810-mediated TNF-α production was dependent upon the activation of these kinases. We further found that neutralizing antibodies against Toll-like receptor 4 (TLR4) significantly inhibited TNF-α secretion. Taken together, our results indicated that Nfa34810 is a virulence factor of N. farcinica and plays an important role during infection. Nfa34810-induced production of TNF-α in macrophages also involves ERK, JNK, and NF-κB via the TLR4 pathway.

Nocardia farcinica as a cause of chronic meningitis - case report

Background

Nocardiosis is an uncommon disease caused by aerobic gram-positive bacteria Nocardia spp. Although it is usually an opportunistic infection affecting immunocompromised patients, even one third of cases occur in immunocompetent persons. The aim of the study was to describe the course of chronic meningitis due to Nocardia infection.

Case presentation

A 52-year-old patient, chalk miner, suffered from a chronic meningitis caused by an extremely rare pathogen. The patient’s history was complicated and diagnostic process covered multiple examinations and consultations. Initially Kocuria rosea was cultured, yet after molecular examination the result was verified to Nocardia farcinica. Targeted antibiotic treatment was implemented, which resulted in gradual improvement of patients condition. A full recovery was achieved after one year antibiotic therapy.

Conclusions

Nocardia farcinica is an uncommon but possible cause of chronic meningitis.

In the case of a chronic meningitis of unknown origin multiple cerebrospinal fluid cultures should be performed as the identification of pathogen may be crucial for patient’s recovery.

In case of unusual culture, such as Kocuria spp. PCR should be performed.

Two cases of Nocardia bacteraemia in solid organ transplant recipients

Nocardiosis is an opportunistic infection occurring in immunosuppressed patients. While disseminated nocardiosis is common in immunosuppressed patients, Nocardia bacteraemia is rare. There are few reports of Nocardia bacteraemia following solid organ transplantation. We report two cases of Nocardia bacteraemia in solid organ transplant recipients-Nocardia cyriacigeorgica bacteraemia in liver transplant recipient and concomitant Nocardia farcinica bacteraemia and cyclosporiasis in a heart transplant recipient. Prompt recognition of early bacteraemia with initiation of antibiotic therapy may avoid the complications of disseminated disease in the solid organ transplant recipients.

Orbital and intracranial Nocardia farcinica infection caused by trauma to the orbit: a case report

BACKGROUND

Localized `and disseminated Nocardia farcinica infection is frequently reported in immunocompromised patients. However, orbital nocardiosis is rare, and, to our knowledge, traumatic orbital nocardiosis that affects the brain has never been described. Here, we report a case of traumatic orbital and intracranial N. farcinica infection in an immunocompetent patient.

CASE PRESENTATION

A 35-year-old man, who was immunocompetent, to the best of our knowledge and as per the absence of immunodeficiency symptoms, with orbital trauma caused by the penetration of a rotten bamboo branch developed lesions in the orbit and brain. Subsequently, he underwent debridement and received broad-spectrum antibiotic therapy, but orbital infection occurred, with drainage of pus through the sinus tract. The patient then underwent endoscope-assisted local debridement. Bacterial culture of the sinusal pus was positive for N. farcinica, and a combined intracranial infection had developed. The disease was treated effectively by trimethoprim-sulfamethoxazole and ceftriaxone sodium therapy. The patient remained infection free and without complications at the 14-month follow-up.

CONCLUSIONS

Traumatic orbital and intracranial infection caused by N. farcinica is a rare infectious disease, and atypical presentations easily lead to misdiagnosis. When a patient presents with an atypical orbital infection that is unresponsive to empirical broad-spectrum antibiotics, along with suspicious neurologic symptoms, Nocardia infection should be considered. Identification by bacterial culture is the gold standard. Complete local debridement and appropriate antibiotic treatment are keys to the treatment of the disease.

Nocardia farcinica meningitis in a patient with high-grade astrocytoma

We describe a case of 91-year-old male with astrocytoma who developed meningitis caused by Nocardia farcinica. He had a past medical history of anaplastic astrocytoma grade III. Endocranial computed tomography (CT) scan revealed mass lesion in the left occipital region associated with perilesional edema, without evidence of midline shift issue. The analyses of cerebrospinal fluid (CSF) revealed neutrophilic pleocytosis, hyperproteinorrachia and hypoglycorrhachia. Combined antimicrobial therapy was initiated (vancomycin, meropenem, acyclovir). CSF culture revealed Nocardia farcinica. Susceptibility testing revealed intermediate sensitivity to meropenem and antibiotic treatment was switched to trimethoprim-sulfamethoxazole and imipenem. After 7 days of treatment the patient developed progressive dyspnea. The chest CT scan revealed bilateral pleural effusion and alveolar infiltrate mostly in the right lobe. Ceftriaxone was added to the therapy, but the outcome was lethal. Nocardia spp. should be considered as differential diagnosis in the patients with brain tumor or meningitis in the setting of immune suppression and corticosteroid use. CSF cultures should be incubated longer with aim to allow fastidious organisms to grow, such as Nocardia spp.

Prostate abscess caused by Nocardia farcina

Nocardia farcinica usually infects the respiratory tract and can sometimes cause central nervous system infections; however, it rarely infects the prostate. Here we report the first case of N. farcinica detected in the purulence specimen drained from a prostate abscess. A 70-year-old Japanese male receiving steroid and cyclosporine treatment came to our department with chief complaint of turbid urine. Computed tomography revealed a low-density lesion in his prostate. Antibiotic administration and prostatic drainage were effective. N. farcinica was detected in the cultures of urine and prostatic drainage purulence specimens. Nocardiosis should be included in the differential diagnosis in immunosuppressive patients with prostate abscess.

An immunoproteomic approach to identify antigenic proteins in Nocardia farcinica IFM 10152

Nocardia farcinica is the etiological agent of nocardiosis, leading to serious pulmonary or systemic infections. To uncover virulence factors and early diagnostic markers, secreted proteins of N. farcinica IFM 10152 were analyzed using an immunoproteome-based approach. A total of 5 proteins were identified by matrix-assisted laser desorption (MALDI-TOF-MS). Bioinformatic analyses showed that the identified proteins were involved in defense against the host innate immune system and required for pathogenesis. All proteins were expressed in E. coli and antigenicity was analyzed with Western blot. To our knowledge, these proteins with antigenicity were identified for the first time in N. farcinica and they may help elucidate the pathogenesis underlying Nocardia and provide potential future diagnostic markers.

Disseminated Nocardia farcinica infection presenting as a paravertebral abscess in a patient with systemic lupus erythematosus

Disseminated Nocardia infections occur particularly in immunosuppressed hosts and are most often due to Nocardia farcinica, Nocardia nova, and Nocardia cyriacigeorgica. Here, we report an unusual case of disseminated N. farcinica infection presenting as a paravertebral abscess in a patient with systemic lupus erythematosus.

Nocardia intracranial mycotic aneurysm associated with proteasome inhibitor

We report a case of Nocardia farcinica ruptured intracranial mycotic aneurysm associated with bortezomib and corticosteroid treatment in a multiple myeloma patient. The patient was treated with trimethoprim-sulfamethoxazole and moxifloxacin together with surgical repairment of intracranial mycotic aneurysm.

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

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

A case of empyema and septic arthritis due to Nocardia farcinica

Septic arthritis due to Nocardia sp. should be suspected when a patient with risk factors such as pneumoconiosis or diabetes mellitus develops joint symptoms, especially if the patient has had nocardiosis in other sites.

Nocardia farcinica Brain Abscess: Report of 3 Cases

BACKGROUND

Central nervous system nocardial infection is a rarely reported disease that usually affects patients with predisposing and debilitating conditions but also the immunocompetent population. The most common variant affecting the brain is Nocardia farcinica. Management of brain nocardiosis is troublesome and requires consideration of the severity of the underlying systemic disease, the difficulties in identifying the bacterium, and the frequent delay in initiating adequate therapy.

CASE DESCRIPTION

We present 3 cases of N. farcinica brain abscess (single, multiloculated, and multifocal) diagnosed in 3 patients with predisposing factors that could be successfully cured. The patients underwent craniotomy, evacuation of the purulent collection, and partial resection of the abscesses' walls. Confirmation of N. farcinica species was achieved using specific polymerase chain reaction sequencing of the 16S ribosome RNA gene. Antibiotic therapy was selected on susceptibility tests and was maintained for 10 months (1 case) and 12 months (2 cases).

CONCLUSIONS

Brain nocardiosis needs to be suspected primarily (though not exclusively) in immunocompromised patients presenting with neurologic deficit and harboring intracerebral lesions resembling brain tumors. Early identification of the specific species is paramount in order to initiate long-term antibiotic therapy, acknowledging the inherent resistance of N. farcinica to third-generation cefalosporins and its susceptibility to trimethoprim-sulphamethoxazole. According to the literature, surgical excision or aspiration of the brain abscess seems to provide good chances of eradication of the disease. In our experience, successful outcome was achieved with subtotal resection and prolonged and adequate antibiotic therapy.

Disseminated Nocardia farcinica in an immunocompetent patient

Nocardia farcinica is a gram-positive, partially acid-fast, methenamine silver-positive aerobic actinomycete that is infrequently associated with nocardiosis. The relative frequency of Nocardia farcinica isolates in nocardiosis is unknown but thought to be under diagnosis. It is increasingly been recognized in immunocompetent patients.

We report a case of disseminated Nocardia farcinica causing brain abscess in 55 year old immunocompetent man who was successfully treated with long term antibiotics.

The present report illustrates that early detection and treatment of disseminated Nocardia farcinica can lead to a good outcome.

The role of oral co-trimoxazole in treating Nocardia farcinica keratitis-a case report

Background

Nocardia farcinica is one of the more recently identified species of the Nocardia genus. Nocardia farcinica keratitis is a rare occurrence, with only eight previously reported cases. Semi-permeable rigid contact lens use was associated with one of these reported cases. We report the first case of extended wear soft contact-lens-related Nocardia farcinica keratitis and recommend a new treatment regime.

Findings

A 47-year-old lady presented with a right eye keratitis after wearing her extended wear soft contact lenses for five continuous weeks. There was no history of trauma or swimming with contact lenses in. Empirical ciprofloxacin and tobramycin eye drops were not tolerated due to ocular surface irritation on application; and instead, empirical treatment was with chloramphenicol and fortified gentamicin 1.5 % eye drops. Corneal scrapings grew Nocardia farcinica after 3 weeks—sensitive to amikacin and co-trimoxazole. Treatment was changed to amikacin 2.5 % eye drops, resulting in partial resolution of the corneal infiltrates. Oral co-trimoxazole 160/800 mg BD was added, due to cultured drug sensitivity and its high ocular penetration, with good results and a final right eye best-corrected visual acuity of 6/5.

Conclusion

Nocardia farcinica keratitis should be considered in the differential diagnosis of contact-lens-related keratitis. We report the first case occurring in association with extended wear soft contact lenses. Nocardia species can mimic fungal and Acanthamoeba keratitis. Treatment with oral co-trimoxazole has not been previously reported. This case demonstrates a role for co-trimoxazole in treating Nocardia farcinica keratitis based on cultured drug sensitivities.