Clinical experience with linezolid for the treatment of nocardia infection

Successful maintenance treatment of disseminated nocardiosis with cerebral abscess in a severely immunocompromised patient allergic to trimethoprim-sulfamethoxazole using moxifloxacin and high-dose minocycline: A case report

Nocardiosis in patients after allogeneic hematopoietic stem cell transplantation (HSCT) is rare, but is associated with a significant mortality risk. Although trimethoprim-sulfamethoxazole (TMP/SMX) remains the cornerstone of nocardiosis treatment, optimal alternative therapies for patients intolerant to TMP/SMX are not well-established. Herein, we report a case of disseminated nocardiosis with bacteremia and multiple lesions in the lungs and brain caused by Nocardia farcinica, in a 60-year-old man who had previously undergone allogeneic HSCT and was receiving immunosuppressants for severe chronic graft-versus-host disease. The patient received atovaquone for the prophylaxis of Pneumocystis pneumonia because of a previous serious allergic reaction to TMP/SMX. The patient was initially treated with imipenem/cilastatin and amikacin, which were later switched to ceftriaxone and amikacin based on the results of antimicrobial susceptibility testing. After switching to oral levofloxacin and a standard dose of minocycline, the patient experienced a single recurrence of brain abscesses. However, after switching to oral moxifloxacin and high-dose minocycline, the patient did not experience any relapses during the subsequent two years and seven months of treatment. In treating nocardiosis with brain abscesses, it is crucial to select oral antibiotics based on the antimicrobial susceptibility test results and pharmacokinetics, especially when TMP/SMX is contraindicated. A combination of oral moxifloxacin and high-dose minocycline could be a promising alternative therapy.

A Case of Yellow Nail Syndrome Complicated with Pulmonary Infection Due to Nocardia cyriacigeorgica

Yellow nail syndrome (YNS) is a rare clinical syndrome characterized by nail bed changes, pulmonary involvement, and lymphatic drainage disorders. Pulmonary involvement usually manifests as bronchiectasis, bronchiolitis, and pleural effusion. There are few studies on yellow nail syndrome combined with opportunistic infection. Here, we report a case of clinically diagnosed YNS combined with Nocardia cyriacigeorgica infection and the course of treatment used, which can provide some useful information for clinicians to better understand this rare illness.

Disseminated nocardiosis caused by Nocardia otitidiscaviarum-A case report

In this article we report a case of disseminated nocardiosis caused by Nocardia otitidiscaviarum in an immunocompetent patient with chronic obstructive pulmonary disease (COPD) who complained of a cough, followed by skin and intracranial lesions. On metagenomic next-generation sequencing (mNGS) technology of respiratory samples (bronchoalveolar lavage fluid, BALF) Nocardia otitidiscaviarum was identified. The patient was treated with therapy combined with a low dose of TMP-SMX and imipenem cilastatin sodium and had a favorable outcome. The timely diagnosis of Nocardia with the help of mNGS technology and early rational treatment of TMP-SMX can help improve the prognosis.

Exposing the Masquerade of Nocardia otitidiscaviarum Pneumonia: A Case Report

We present a rare case of an immunocompetent 49-year-old male agriculturalist from India diagnosed with Nocardia otitidiscaviarum pneumonia. Nocardia species are ubiquitous gram-positive, partially acid-fast bacilli that predominantly infect immunocompromised individuals. Only 0.3% to 2.9% of all nocardiosis cases are attributed to N. otitidiscaviarum. The patient presented with a 25-day history of wet cough and high-grade fever, with bilateral bronchial breath sounds on chest auscultation and findings consistent with pneumonia on chest X-ray. During hospitalization, multiple treatment revisions were made. On admission, empiric antibiotic therapy against community-acquired pneumonia was initiated. Later, GeneXpert sputum testing for Mycobacterium tuberculosis complex (MTBC) was positive for MTBC DNA. Suspected tuberculosis with a secondary infection prompted a treatment switch to antitubercular therapy (ATT) along with meropenem. Despite changes to treatment, the patient continued to deteriorate with no signs of clinical improvement. ATT with meropenem was discontinued when a repeat GeneXpert for MTBC was negative, ruling out tuberculosis. Slow-growing bronchial wash culture identified the rare pathogen N. otitidiscaviarum, prompting an urgent referral to a specialized Infectious Diseases team. Treatment was then tailored according to antibiotic resistance-sensitivity testing. Targeted multidrug antibiotic therapy with trimethoprim-sulfamethoxazole and amikacin against N. otitidiscaviarum facilitated gradual clinical improvement. This case underscores the importance of considering uncommon pathogens in differential diagnosis and highlights the critical role of microbiological diagnostics in guiding effective treatment. Drug resistance and changing bacterial pathogenicity trends must not be overlooked. The round-about antibiotic treatment changes in this case point to the necessity for faster diagnostic methods in identifying Nocardia species. Further research into rapid diagnostic methods and up-to-date treatment guidelines are warranted to optimize outcomes in nocardiosis management.

Guidelines for Antibiotics Prescription in Critically Ill Patients

How to cite this article: Khilnani GC, Tiwari P, Mittal S, Kulkarni AP, Chaudhry D, Zirpe KG, et al. Guidelines for Antibiotics Prescription in Critically Ill Patients. Indian J Crit Care Med 2024;28(S2):S104-S216.

Caser Report: A Rare Case of Pulmonary Nocardiosis Caused by Nocardia pseudobrasiliensis After Liver Transplantation

Nocardia is a gram-positive bacillus with the microscopic appearance of branching hyphae and is mainly distributed in the soil. Nocardiosis more frequently occurs in immunosuppressed patients. Since nocardiosis has a high mortality rate, immediate diagnosis and treatment are needed. We report the first case of pulmonary nocardiosis caused by Nocardia pseudobrasiliensis after liver transplantation. A 58-year-old woman underwent living-donor transplantation for primary biliary cholangitis. Seven months after transplantation, she came to our hospital complaining of fever and anorexia. Computed tomography of the lungs showed a 45 mm large nodule affecting the upper lobe of the left lung. We started administering empiric antibiotics and tapering immunosuppression, but the patient's condition gradually worsened, and lung lesions increased. On the fifth day after hospitalization, bacteria developed from sputum cultures were identified as N. pseudobrasiliensis by matrix-assisted laser desorption ionization time of flight mass spectrometry. We started treatment with trimethoprim-sulfamethoxazole. The patient's clinical symptoms and laboratory data improved quickly. After one month of hospitalization, this patient was discharged. Then, the lung lesion almost vanished. Ten years after her transplant, the patient is alive with a well-functioning graft.

Nocardia farcinica brain abscess with torque teno virus co-infection: A case report

Background

Brain abscesses caused by Nocardia are rare and difficult to diagnose. Nocardia farcinica is among the most common species; however, the conventional diagnosis of N. farcinica infection consists of cerebrospinal fluid (CSF) and blood culture and Gram staining. These procedures prolong the time to diagnosis and initiating treatment.

Case presentation

A 69-year-old woman with diabetes mellitus presented with headaches and dizziness persisting for 2 weeks, which was initially diagnosed as a brain abscess. Due to the unusual presentation and rapid progression of symptoms, she underwent surgical resection of the brain abscess. No pathogens were detected in blood or CSF cultures. However, metagenomic next-generation sequencing (mNGS) identified N. farcinica and Torque teno virus in pus extracted from the abscesses. The patient received appropriate antibiotic therapy and recovered fully without any residual neurological deficits.

Conclusion

mNGS useful for prompt diagnosis and selection of antibiotic therapy for brain abscesses caused by Nocardia. Surgical intervention is necessary in some cases.

How an Antimicrobial Stewardship Team Treated a Nocardia farcinica-Associated Brain Abscess: A Case Report

Nocardia species, which are ubiquitous in the environment, form lesions primarily in immunocompromised patients via oral or cutaneous infection. Some of these Nocardia species, such as N. farcinica, also infect the central nervous system via hematogenous dissemination, which rarely results in brain abscesses. Notably, N. farcinica is resistant to numerous antimicrobial drugs used in empirical therapy, necessitating the intervention of an infectious disease specialist. To date, no case of antimicrobial stewardship teams (ASTs) playing a central role in community hospitals without an infectious disease specialist has been reported. Here, we describe a case of N. farcinica-associated brain abscess in a small-to-medium-sized hospital with no infectious disease department or specialist, in which the AST assisted in the identification of the causative organism and in selecting appropriate therapeutic agents, ultimately leading to a cure. The patient was an 88-year-old man with a high fever. He had been taking prednisolone (10-15 mg/day) for approximately 1 year for pemphigoid. Considering the possibility of fever owing to bacteremia of cutaneous origin, ampicillin/sulbactam antimicrobial therapy at 6 g/day was initiated. A subsequent close examination led to the diagnosis of a brain abscess. Emergency abscess drainage was performed by a neurosurgeon, and postoperative antimicrobial combination therapy comprising ceftriaxone (4 g/day), vancomycin (2 g/day), and metronidazole (1,500 mg/day) was commenced. The AST suspected Nocardia infection earlier, but further testing was difficult to perform at this facility. Therefore, by requesting assistance from Nagoya University Hospital, we performed early bacterial identification by mass spectrometry and appropriate antimicrobial susceptibility testing by a custom panel on day 11. The patient was non-responsive to all the previously used antibiotics at the time of admission. On day 13 after admission, the patient was successfully treated with trimethoprim-sulfamethoxazole (TMP-SMX) and imipenem/cilastatin sodium, and the patient was cured. The AST can be as effective as an infectious disease specialist when a strong working relationship is established between the team and clinicians. Further, the activities of the AST can improve patient survival via active medical support in collaboration with attending physicians.

Brain Abscesses by Nocardia: An Interesting Case

The successful management of disseminated Nocardia infection is not well described in medical literature. Immunocompetent individuals presenting with complicated and widespread Nocardia infection is an uncommon phenomenon. We describe an interesting case of a large Nocardia abscess in the brain in an immunocompetent patient that was aspirated. The patient clinically improved and was discharged home on a prolonged course of intravenous antibiotics and close outpatient follow-up. He successfully finished the antibiotic therapy for one year, and repeat imaging studies suggested the resolution of the abscess. With this case, we also intend to do a brief literature analysis about the management of brain abscess caused by Nocardia species.

Epidemiology and in vitro antimicrobial susceptibility of aerobic Actinomycetales in a clinical setting

INTRODUCTION

The incidence of infections caused by aerobic actinomycetes is increasing. Recent changes in taxonomy and the variability in susceptibility patterns among species make necessary a proper identification and antibiotic susceptibility testing.

MATERIAL AND METHODS

Fifty-three strains of aerobic actinomycetes were identified by MALDI-TOF MS using the VITEK MS Mycobacterium/Nocardia kit (bioMérieux, France) in a tertiary hospital in Spain during a six-year period. Antimicrobial susceptibility testing of the isolates was performed using the Sensititre Rapmycoi microdilution panel (Thermo Fisher Scientific, Massachusetts, USA).

RESULTS

Forty strains of Nocardia spp. were identified in the study, being N. farcinica and N. cyriacigeorgica the most prevalent ones. All isolates were susceptible to linezolid and the resistance to amikacin was only observed in one isolate of Gordonia sputi. Resistance to cotrimoxazole was only found in five isolates.

CONCLUSIONS

Routine identification and antimicrobial susceptibility testing of aerobic actinomycetes is advisable for an efficient identification of species and effective treatment.

Metagenomic next-generation sequencing provides prognostic warning by identifying mixed infections in nocardiosis

Nocardia is an opportunistic pathogen that mainly involves immunosuppressed patients and causes a high mortality rate. As an emerging approach to detect infectious pathogens, metagenomic next-generation sequencing (mNGS) was reported in the detection of Nocardia. However, there is no evidence demonstrating the effect of mNGS on the prognosis of Nocardia infection. In this retrospective study, we included 18 nocardiosis patients. Nocardia species were detected by mNGS from their clinical samples. All the patients were diagnosed with nocardiosis by clinical experts through a comprehensive evaluation. Of these 18 patients, fever is the most frequent initial symptom. Compared to traditional culture methods, mNGS provides a faster turnaround time (TAT) and higher sensitivity. Pulmonary nocardiosis was the most common clinical presentation in the study. mNGS detected 13 types of Nocardia species, of which Nocardia abscessus and Nocardia cyriacigeorgica were the most common species. The study’s most noteworthy discovery is that mNGS outperforms culture at detecting mixed infections (more than one pathogen detected in one clinical specimen, including bacteria, fungi, and excluding virus), and number of infectious species was an independent risk factor for nocardiosis patients’ prognostics after adjusting age, ICU days, gender and underlying diseases (adjusted HR = 1.47, 95% CI: 1.09-1.98, p = 0.011). As a result, we believe that by detecting mixed infections (more than one pathogenic species), mNGS can provide a clinical risk warning for the prognosis of nocardiosis.

Identification and antimicrobial susceptibility of referred Nocardia isolates in Victoria, Australia 2009-2019

Introduction. Nocardia is an opportunistic pathogen that can cause significant morbidity and mortality, particularly in the immunocompromised host. Antimicrobial susceptibility profiles vary across Nocardia spp. and vary within Australia as well as worldwide. Knowledge of local susceptibility patterns is important in informing appropriate empiric antimicrobial therapy.Gap Statement. This is the largest study to date in Australia that correlates antimicrobial susceptibility profiles with molecular identification of Nocardia species. It is the first study that examines isolates from multiple institutions across the state of Victoria, Australia.Aim. To investigate the species distribution and antibiotic susceptibility of Nocardia spp. isolates referred to the Mycobacterial Reference Laboratory (MRL) in Victoria, Australia from 2009 to 2019.Methodology. We conducted a retrospective review of Nocardia spp. isolates which were identified using molecular sequencing. Antimicrobial susceptibility testing was performed using standardized broth microdilution method with Sensititre RAPMYCO1 plates. Species distribution and antibiotic susceptibility profiles were analysed.Results. In total, 414 Nocardia isolates were identified to 27 species levels, the majority originating from the respiratory tract (n=336, 81.2 %). N. nova (n=147, 35.5 %) was the most frequently isolated, followed by N. cyriacigeorgica (n=75, 18.1 %). Species distribution varied by isolate source, with N. farcinica and N. paucivorans found more commonly from sterile sites. Linezolid and amikacin had the highest proportion of susceptible isolates (100 and 99% respectively), while low susceptibility rates were detected for ceftriaxone (59 %) and imipenem (41 %). Susceptibility to trimethoprim sulfamethoxazole varied by species (0-100 %).Conclusion. This is the largest study to date in Australia of Nocardia species distribution and antimicrobial susceptibility patterns. N. farcinica and N. paucivorans were more likely to be isolated from sterile sites, while N. brasiliensis and N. otitidiscvarium were more likely to be isolated from skin and soft tissue. First line therapeutic antimicrobial recommendations by local guidelines were not necessarily reflective of the in vitro susceptibility of Nocardia isolates in this study, with high susceptibility detected for linezolid and amikacin, but poor susceptibility demonstrated for ceftriaxone and imipenem. Profiles for trimethoprim-sulfamethoxazole varied across different Nocardia species, warranting ongoing susceptibility testing for targeted clinical use.

A fatal case of disseminated nocardiosis due to Nocardia otitidiscaviarum resistant to trimethoprim-sulfamethoxazole: case report and literature review

Background

Disseminated nocardiosis still causes significant morbidity and mortality and is often caused by Nocardia asteroides, N. basiliensis, and N. farcinica and are often treated with trimethoprim–sulfamethoxazole (TMP–SMX). Nocardia otitidiscaviarum (N. otitidiscaviarum) rarely causes disseminated disease and resistance to TMP–SMX is even more rare.

Case presentation

A 37-year-old woman with metastatic breast cancer and right ear deafness with recent occupational gardening and manipulating soil, presented to the hospital with first time seizure and multiple skin nodules. Magnetic resonance imaging (MRI) showed ring enhancing lesions, biopsy of the skin and brain lesions grew N. otitidiscaviarum. She was empirically treated with TMP–SMX and Imipenem–Cilastatin, however, almost three weeks into therapy, susceptibility results revealed it to be resistant to both antimicrobials, she was subsequently changed to Amikacin, Linezolid, Moxifloxacin, and Doxycycline but ultimately died.

Conclusions

This case report highlights the importance of suspecting a rare Nocardia species in patients at risk with proper occupational exposure, moreover, TMP–SMX resistance should be suspected with lack of clinical response, this may have important implications on clinical practice when facing similar infections.

Long-term use of tedizolid for pulmonary nocardiosis

Nocardiosis usually occurs in immunocompromised patients and causes infections in various organs, including the lungs, skin, and organs of the central nervous system. Herein, we report the case of a patient with minimal change nephrotic syndrome who had been on immunosuppressive drugs and developed pulmonary nocardiosis due to Nocardia nova complex and Pneumocystis pneumonia. For pulmonary nocardiosis, trimethoprim-sulfamethoxazole, linezolid, and clarithromycin were initiated sequentially, but were subsequently discontinued due to side effects; the treatment was completed with tedizolid. Tedizolid was used safely for 200 out of 286 days of antibiotic treatment, and clinical improvement was observed. Tedizolid is a bacteriostatic oxazolidine antibiotic that inhibits bacterial protein synthesis, the same mechanism as its predecessor, linezolid. Tedizolid is thought to cause less frequent myelosuppression than linezolid, at least for short-term use. In the future, tedizolid may be a promising alternative to linezolid in cases of nocardiosis that usually require long-term treatment.

Immediate and Delayed Hypersensitivity Reactions to Antibiotics: Aminoglycosides, Clindamycin, Linezolid, and Metronidazole

Hypersensitivity reactions including IgE-mediated and delayed cell-mediated reactions to aminoglycosides, clindamycin, linezolid, and metronidazole are rare. For aminoglycosides, allergic contact dermatitis is the most frequent reaction for which patch testing can be a useful step in evaluation. For clindamycin, delayed maculopapular exanthems are the most common reactions. There are case reports of clindamycin associated with drug rash with eosinophilia and systemic symptoms (DRESS), acute generalized exanthematous pustulosis (AGEP), acute febrile neutrophilic dermatosis, and symmetrical drug-related intertriginous and flexural exanthema (SDRIFE). For linezolid, cases of hypersensitivity were exceedingly rare and included urticaria, angioedema, anaphylaxis, delayed rashes, and DRESS. For metronidazole, only rare cases were found across a broad spectrum of reactions including allergic contact dermatitis, fixed drug eruption, angioedema, anaphylaxis, serum sickness-like reaction, SJS/TEN, AGEP, SDRIFE, and a possible case of DRESS. IgE-mediated reactions and anaphylaxis to these types of antibiotics are uncommon, and reports of skin testing concentrations and desensitization protocols are largely limited to case reports and series. Non-irritating skin testing concentrations have been reported for gentamycin, tobramycin, and clindamycin. Published desensitization protocols for intravenous and inhaled tobramycin, oral clindamycin, intravenous linezolid, and oral and intravenous metronidazole have also been reported and are reviewed.

Case Report: A Severe and Multi-Site Nocardia farcinica Infection Rapidly and Precisely Identified by Metagenomic Next-Generation Sequencing

Nocardia genus is an aerobic, gram-positive, and opportunistic pathogen, which mainly affects cell-mediated immunosuppressed patients. Early diagnosis and treatment greatly improve prognosis. However, the limitation of golden standard-bacterial culture exists. Here, we report a 61-year-old male with pneumonia, sepsis and intermuscular abscesses induced by Nocardia farcinica. Venous blood culture reported negative results. Former improper diagnosis and treatment did not improve his condition. With the assistant of metagenomic next-generation sequencing, the pathogen was identified as Nocardia farcinica. He was then applied with accurate treatment and had a remarkable clinical and radiological improvement.

Epidemiology and in vitro antimicrobial susceptibility of aerobic Actinomycetales in a clinical setting

INTRODUCTION

The incidence of infections caused by aerobic actinomycetes is increasing. Recent changes in taxonomy and the variability in susceptibility patterns among species make necessary a proper identification and antibiotic susceptibility testing.

MATERIAL AND METHODS

Fifty-three strains of aerobic actinomycetes were identified by MALDI-TOF MS using the VITEK MS Mycobacterium/Nocardia kit (bioMérieux, France) in a tertiary hospital in Spain during a six-year period. Antimicrobial susceptibility testing of the isolates was performed using the Sensititre Rapmycoi microdilution panel (Thermo Fisher Scientific, Massachusetts, USA).

RESULTS

Forty strains of Nocardia spp. were identified in the study, being N. farcinica and N. cyriacigeorgica the most prevalent ones. All isolates were susceptible to linezolid and the resistance to amikacin was only observed in one isolate of Gordonia sputi. Resistance to cotrimoxazole was only found in five isolates.

CONCLUSIONS

Routine identification and antimicrobial susceptibility testing of aerobic actinomycetes is advisable for an efficient identification of species and effective treatment.

Revisiting nocardiosis at a tertiary care institution: Any change in recent years?

OBJECTIVE

To analyse relevant changes in incidence, clinical and microbiological characteristics of nocardiosis over the last 24 years at the current institution.

MATERIALS AND METHODS

The clinical records of patients with nocardiosis (2006-2018) were reviewed and then compared with a previous cohort (1995-2006). Nocardia isolates were identified by 5'-end-16S-rRNA-gene-PCR targeting the first 500 bp of the gene and sequencing. Susceptibility tests were determined by broth microdilution (CLSI guidelines).

RESULTS

Forty-two patients (64.3% male) with nocardiosis were evaluated in the recent cohort: 51.2% had COPD, 43.9% were on corticosteroid therapy and 31.7% had cancer. The incidence of nocardiosis varied from 6.3 to 7.1/100,000 admissions (p = 0.62). There was a decrease in HIV patients (27% vs. 4.9%, p = 0.01) and solid organ transplantation (SOT) recipients (18.9% vs. 2 .4%, p = 0.01). Cases with pulmonary involvement had increased (70.3% vs. 90.5%, p = 0.04). Nocardia species were similar but the most common were N. cyriacigeorgica (32.4% vs. 40.5%, p = 0.49) and N. farcinica (24.3% vs. 14.3%, p = 0.39). Antibiotic resistance remained stable: cotrimoxazole (10.8% vs. 5.7%, p = 0.68), imipenem (5.4% vs. 5.6%, p = 1.0); amikacin and linezolid were 100% active. No differences were found in breakthrough nocardiosis (21.6% vs. 9.8%, p = 0.21) or related mortality (21.6% vs. 21.4%, p = 1.0). The multivariate analysis confirmed that nocardiosis caused by N. farcinica is a risk factor for poor outcome (p = 0.045).

CONCLUSIONS

Nocardiosis incidence has remained stable. It mainly affected elderly patients with chronic respiratory conditions and those on corticosteroid treatment. Infections in HIV and SOT patients have practically disappeared. Pulmonary involvement remains the most common area to be affected. Nocardiosis caused by N. farcinica is apparently a risk factor for poor clinical outcome.

Isolated Nocardiosis, an Unrecognized Primary Immunodeficiency?

Nocardiosis is an infectious disease caused by the gram-positive bacterium Nocardia spp. Although it is commonly accepted that exposure to Nocardia is almost universal, only a small fraction of exposed individuals develop the disease, while the vast majority remain healthy. Nocardiosis has been described as an "opportunistic" disease of immunocompromised patients, suggesting that exposure to the pathogen is necessary, but a host predisposition is also required. Interestingly, increasing numbers of nocardiosis cases in individuals without any detected risk factors, i.e., without overt immunodeficiency, are being reported. Furthermore, a growing body of evidence have shown that selective susceptibility to a specific pathogen can be caused by a primary immunodeficiency (PID). This raises the question of whether an undiagnosed PID may cause nocardiosis affecting otherwise healthy individuals. This review summarizes the specific clinical and microbiological characteristics of patients with isolated nocardiosis published during the past 30 years. Furthermore, it gives an overview of the known human immune mechanisms to fend off Nocardia spp. obtained from the study of PIDs and patients under immunomodulatory therapies.

Molecular identification of Nocardia species causing endophthalmitis using multilocus sequence analysis (MLSA): a 10-year perspective

Introduction. Nocardia spp. can cause several ocular infections, such as keratitis, endophthalmitis and scleral abscesses. Molecular identification of Nocardia spp. by 16S rDNA sequencing is the gold standard method at present for species identification, but closely related species can only be identified by multilocus sequence analysis (MLSA) of housekeeping genes.Aim. The major objective was to profile Nocardia species, antibiotic susceptibility patterns and clinical outcomes in endophthalmitis patients.Methodology. Between January 2009 and December 2018, endophthalmitis patients who were diagnosed with Nocardia infection based on microscopic and culture characteristics were selected. Antibacterial susceptibility tests were performed and Nocardia speciation was performed using MLSA and phylogenetic tree analysis of the 16 s rRNA gene and the gyrB, hsp65 and secA1 genes.Results. A total of 43 culture-proven patients were identified during the study period. All isolates were 100 % sensitive to amikacin and 98 % resistant to ceftazidime. Fluoroquinolone sensitivity was observed in the range of 58 to 72 %. Year-wise analysis of antibiotic resistance patterns revealed there was a significant increase in resistance to fluoroquinolones. Twenty-two isolates were stored and six different species were identified. Nocardia farcinica (n=10) was found to be the most predominant, followed by Nocardia cyriacigeorgica (n=4), Nocardia otitidiscaviarum (n=3), Nocardia amikacinitolerans (n=2), Nocardia puris (n=2) and Nocardia higoensis (n=1).Conclusions. N. farcinica is the major pathogen, and this is the first report to identify N. otitidiscaviarum, N. amikacinitolerans and N. higoensis as causing endophthalmitis. Overall, visual outcomes were mostly poor even after aggressive management.

Safety and Outcomes of Linezolid Use for Nocardiosis

Background

Tropical Australia has a high incidence of nocardiosis, with high rates of intrinsic antimicrobial resistance. Linezolid, the only antimicrobial to which all local Nocardia species are susceptible, has been recommended in empirical combination treatment regimens for moderate-severe Nocardia infections at Royal Darwin Hospital (RDH) since 2014. We report the safety and efficacy of linezolid use for nocardiosis in this setting.

Methods

We identified cases through a retrospective review of all RDH Nocardia isolates from December 2014 to August 2018 and included 5 linezolid-treated cases from a previous cohort. Laboratory, demographic, and clinical data were included in the primary analysis of safety and treatment outcomes.

Results

Between 2014 and 2018, Nocardia was isolated from 35 individuals; 28 (80%) had clinically significant infection and 23 (82%) received treatment. All isolates were linezolid-susceptible. Safety and efficacy were assessed for 20 patients receiving linezolid-containing regimens and 8 receiving nonlinezolid regimens. Median linezolid induction therapy duration was 28 days. Common adverse effects in those receiving linezolid were thrombocytopenia (45%) and anemia (40%). Adverse events prompted discontinuation of trimethoprim-sulfamethoxazole more often than linezolid (40% vs 20%). Linezolid therapeutic drug monitoring was used in 1 patient, with successful dose reduction and outcome. There was no difference in 30-day survival between those treated with linezolid (90%) vs no linezolid (87%). One Nocardia-attributed death occurred during linezolid therapy.

Conclusions

Linezolid is safe and efficacious in empirical treatment for moderate to severe nocardiosis in a monitored hospital setting, with 100% drug susceptibility and no difference in adverse events or outcomes compared with nonlinezolid regimens.

Multiple brain abscesses due to Nocardia spp. in an immunocompetent patient

La infección por Nocardia spp. no es común en pacientes inmunocompetentes. El tratamiento antimicrobiano empírico dirigido según las regiones anatómicas, no contempla las particularidades del germen y el análisis microbiológico se hace necesario para el tratamiento específico.

A continuación, se presenta el caso de una paciente previamente sana, inmunocompetente y sin factores de riesgo conocidos para la infección por Nocardia spp., con evidencia de compromiso en el parénquima pulmonar y la piel, que posteriormente desarrolló varios abscesos cerebrales.

Disseminated infection with Nocardia otitidiscaviarum in a patient under steroid therapy

Corticosteroid recipients with lung infections should be suspected of having nocardiosis; however, nocardiosis can easily mimic malignancy, tuberculosis, or fungal infection. Though cultural identification is possible, it might be missed due to its slow growth pattern.. Therefore, if filamentous bacteria are seen during staining, plate incubation time should be extended.

Pulmonary nocardiosis caused by Nocardia blacklokiae in an immunocompetent patient

A subset of Nocardia isolates, previously belonging to N. transvalensis, has recently been given the new species designation N. blacklokiae. Here we report a case of pulmonary nocardiosis caused by N. blacklokiae in a 52-year-old immunocompetent woman presenting with low-grade fever and fatigue. The isolated Nocardia strain was resistant to sulfamethoxazole-trimethoprim and amikacin, but susceptible to amoxicillin-clavunate, ceftriaxone, clarithromycin and linezolid. With amoxicillin-clavunate treatment, the patient recovered and her condition remained stable, although recurrence occurred after cessation of the initial treatment. While infection by Nocardia is rare, clinicians should be aware of its resistance to antimicrobials including amikacin and sulfamethoxazole-trimethoprim.

Lymphocutaneous nocardiosis caused by Nocardia brasiliensis in an immunocompetent patient: a case report

Nocardia usually manifests as opportunistic infections in immunocompromised hosts. Here, we report a rare case of an immunocompetent patient with lymphocutaneous nocardiosis. The patient was a 34-year-old man presenting with fever, multiple scattered pustules on both upper limbs and several subcutaneous nodules on the left elbow and forearm. Skin biopsy of the subcutaneous nodule revealed suppurative inflammation of the lymph nodes. Pus cultures were finally identified as Nocardia brasiliensis. The patient fully recovered without relapse after receiving optimized antimicrobial therapy consisting of linezolid combined with sulfonamides. Nocardiosis is a rare opportunistic disease which may be fatal and usually affects immunocompromised hosts, resulting in suppurative and granulomatous inflammation. Nocardia has a long culture cycle, is difficult to diagnose, and is more likely to be neglected in healthy young people. The present case suggests that physicians should be aware that nocardiosis is a differential diagnosis to consider in patients with suppurative infection, especially when anti-infective treatment is ineffective.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Epitope-Based Vaccine Designing of Nocardia asteroides Targeting the Virulence Factor Mce-Family Protein by Immunoinformatics Approach

Nocardia asteroides is the main causative agent responsible for nocardiosis disease in immunocompromised patient viz. Acquired Immunodeficiency Syndrome (AIDS), malignancy, diabetic, organ recipient and genetic disorders. The virulence factor and outer membrane protein pertains immense contribution towards the designing of epitopic vaccine and limiting the robust outbreak of diseases. While epitopic based vaccine element carrying B and T cell epitope along with adjuvant is highly immunoprophylactic in nature. Present research equips immunoinformatics to figure out the suitable epitopes for effective vaccine designing. The selected epitopes VLGSSVQTA, VNIELKPEF and VVPSNLFAV amino acids sequence are identified by HLA-DRB alleles of both MHC class (MHC-I and II) molecules. Simultaneously, these also accessible to B-cell, confirmed through the ABCPred server. Antigenic property expression is validated by the Vaxijen antigenic prediction web portal. Molecular docking between the epitopes and T cell receptor delta chain authenticate the accurate interaction between epitope and receptor with significantly low binding energy. Easy access of epitopes to immune system also be concluded as transmembrane nature of the protein verified by using of TMHMM server. Appropriate structural identity of the virulence factor Mce-family protein generated through Phyre2 server and subsequently validated by ProSA and PROCHECK program suite. The structural configuration of theses epitopes also shaped using DISTILL web server. Both the structure of epitopes and protein will contribute a significant step in designing of epitopic vaccine against N. asteroides. Therefore, such immunoinformatics based computational drive definitely provides a conspicuous impel towards the development of epitopic vaccine as a promising remedy of nocardiosis.

Nocardial endocarditis in native aortic valve with nocardial sepsis in a case of breast cancer

Central venous catheter-associated bacteraemia caused by Nocardia species is very rare; the diagnosis of nocardiosis in patients with cancer is challenging because its clinical presentation is varied, sometimes mimicking metastases, and the high index of clinical suspicion is required for prompt institution of therapy. Herein, we report a case of nocardial sepsis with native aortic valve endocarditis in a patient with breast cancer in whom multidisciplinary team involvement and prompt initiation of therapy have led to successful outcome.

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

PURPOSE OF REVIEW

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

RECENT FINDINGS

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

Isolated abdominal nocardiosis in a pediatric renal transplant recipient

Nocardia infection after RT is uncommon. The most common modes of exposure are inhalation of dust containing nocardia or contaminated soil/water and surgical instruments. Isolated abdominal nocardiosis following RT has not been reported. We report an 11-year-old female who developed nocardia abscesses of the abdomen post-RT. ESRD was secondary to FSGS and she had received multiple immunosuppressive agents prior to transplant. Induction immunosuppression consisted of thymoglobulin and maintenance was with tacrolimus, mycophenolate, and prednisone. There were construction activities in the hospital ward during her hospital stay. Due to immediate recurrence of FSGS in the allograft, she received plasma exchange, rituximab, and IVIG. Anti-infective prophylaxis consisted of TMP-SMX, valganciclovir, and nystatin. She developed multiple loculated fluid collections in the abdomen 6 weeks later. Histology of lesions demonstrated suppurative caseating granulomatous inflammation and the AFB culture showed Nocardia farcinica. With the reduction of immunosuppressive agents along with usage of TMP-SMX, imipenem-cilastatin, and linezolid, she had a partial recovery after 9 months with persistent small abscesses but remained asymptomatic clinically. There was no evidence of nocardia infection in lungs and brain. Repeat AFB culture from the lesions was negative. Allograft function remained stable throughout. She remains on oral TMP-SMX therapy. We postulated that she could have acquired nocardia either from the contaminated air particles in the hospital from the construction activities or reactivation of nocardia from prior colonization. Nocardia infection should be suspected in immunocompromised patients with unexplained fever and abdominal pain.

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

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

Indian Antimicrobial Prescription Guidelines in Critically Ill Immunocompromised Patients

How to cite this article: Kulkarni AP, Sengar M, Chinnaswamy G, Hegde A, Rodrigues C, Soman R, Khilnani GC, Ramasubban S, Desai M, Pandit R, Khasne R, Shetty A, Gilada T, Bhosale S, Kothekar A, Dixit S, Zirpe K, Mehta Y, Pulinilkunnathil JG, Bhagat V, Khan MS, Narkhede AM, Baliga N, Ammapalli S, Bamne S, Turkar S, Bhat KV, Choudhary J, Kumar R, Divatia JV. Indian Journal of Critical Care Medicine 2019;23(Suppl 1): S64-S96.

Common Infections Following Lung Transplantation

The lungs are the only transplanted organ in direct contact with the ‘outside world’. Infection is a significant cause of morbidity and mortality in lung transplantation. Early accurate diagnosis and optimal management is essential to prevent short and long term complications. Bacteria, including Mycobacteria and Nocardia, viruses and fungi are common pathogens. Organisms may be present in the recipient prior to transplantation, transmitted with the donor lungs or acquired after transplantation. The degree of immunosuppression and the routine use of antimicrobial prophylaxis alters the pattern of post-transplant infections.

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

RATIONALE

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

PATIENT CONCERNS

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

DIAGNOSES

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

INTERVENTIONS

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

OUTCOMES

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

LESSONS

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

Disseminated Nocardiosis with subretinal abscess in a patient with nephrotic syndrome-a case report

Background

Nocardia infection is uncommon in clinical practice, with most cases occuring as the result of opportunistic infection in immunocompromsed patients. Here, we report a case of disseminated nocardiosis with subretinal abscess in a patient with nephrotic syndrome, and whom is receiving immunosuppressive therapy.

Case presentation

A 58-year-old male presented with decreased vision in his left eye, without redness or floaters, which had persisted for three days. The patient had previously been diagnosed with membranous nephropathy, and as such, had received systemic corticosteroid therapy for four months. Further, the patient had developed pneumonia three weeks prior to this presentation. The ocular lesion appeared as a creamy-white subretinal abscess, with overlying retinal hemorrhages. Subsequent administration of three intravitreal injections of vancomycin and ceftazidime ultimately led to eradication of the intraocular infection, however, two months later, the patient developed a brain abcess. Pathogens isolated from the blood were subsequently identified as Nocardia. The patient was successfully treated via systemic administration of imipenem and trimethoprim-sulfamethoxazole.

Conclusions

Clinicians should be aware of the possibility of Nocardia infections within all immunocompromised patients, as well as the tendency of this infection to disseminate--particularly in the brain. The early detection of Nocardia infections and prolonged treatment of the proper antibiotics may significantly improve the prognosis of this life-threatening infection.

Anti-infective treatment of brain abscess

INTRODUCTION

Brain abscess is an uncommon and potentially life-threatening infection of the CNS that can be caused by a range of different pathogens including bacteria, fungi, and parasites. A multidisciplinary approach is important and anti-infective treatment remains crucial. Here, we review anti-infective treatment of brain abscess. Areas covered: We used the terms '(Brain abscess[ti] AND (antibiotic* OR treatment)) NOT case report'), to conduct a search in the PubMed. Additional papers were identified by cross-reference checking and by browsing textbooks of infectious diseases and neurology.

COMMENTARY

Empiric treatment of bacterial brain abscess consists of cefotaxime and metronidazole with the addition of vancomycin if meticilline-resistant Staphylococcus aureus is suspected. For severely immuno-suppressed patients, for example transplant recipients, voriconazole and trimethoprim-sulfamethoxazole or sulfadiazine should be added. Increased knowledge of the pharmacokinetic profile of anti-infective treatments may help to improve the treatment of brain abscess. Future studies should address efficacy and safety of continuous abscess drainage, mode of anti-infective administration (continuous vs. bolus), and anti-infective treatments in immuno-suppressed patients.

Nocardia spp. Pneumonia in a Solid Organ Recipient: Role of Linezolid

We describe a rare infection with Nocardia spp. (N. pseudobrasiliensis species identification based on high-performance liquid chromatography analysis) in a 68-year-old renal transplant recipient. He presented with pneumonia complicated by hypoxic respiratory failure. He was allergic to sulphonamides. He was initially successfully treated with linezolid. However, he suffered severe sensory neuropathy after 4 months of therapy, necessitating linezolid cessation and completion of treatment with azithromycin. He had clinical and radiological resolution of his pneumonia and was disease free at subsequent follow-up 4 years later. This case highlights the need for alternative therapies for nocardiosis for patients that cannot be treated with sulphonamides due to allergies or/and infection with multidrug-resistant pathogens. It also illustrates the treatment limiting side effects of long-term therapy with linezolid.

In Vitro Susceptibility Testing of Tedizolid against Isolates of Nocardia

There is a paucity of efficacious antimicrobials (especially oral) against clinically relevant species of Nocardia To date, all species of Nocardia have been susceptible to linezolid, the first commercially available oxazolidinone. Tedizolid is a new oxazolidinone with previously reported improved in vitro and in vivo (intracellular) potency against multidrug-resistant strains of Mycobacterium sp. and Nocardia brasiliensis Using the current Clinical and Laboratory Standards Institute-recommended broth microdilution method, 101 isolates of Nocardia spp., including 29 Nocardia cyriacigeorgica, 17 Nocardia farcinica, 13 Nocardia nova complex, 21 Nocardia brasiliensis, 5 Nocardia pseudobrasiliensis, and 5 Nocardia wallacei isolates and 11 isolates of less common species, were tested for susceptibility to tedizolid and linezolid. For the most common clinically significant species of Nocardia, tedizolid MIC₅₀ values were 0.25 μg/ml for N. nova complex, N. brasiliensis, N. pseudobrasiliensis, and N. wallacei, compared to linezolid MIC₅₀ values of 1, 2, 0.5, and 1 μg/ml, respectively. Tedizolid and linezolid MIC₉₀ values were 2 μg/ml for N. nova complex and N. brasiliensis Tedizolid MIC₅₀ and MIC₉₀ values for both N. cyriacigeorgica and N. farcinica were 0.5 μg/ml and 1 μg/ml, respectively, compared to linezolid MIC₅₀ and MIC₉₀ values of 2 and 4 μg/ml, respectively. Based on MIC₉₀ values, this study showed that tedizolid was 2- to 3-fold more active than linezolid in vitro against most common species of Nocardia, with the exception of the N. nova complex and N. brasiliensis, for which values were the same. These results may warrant evaluation of tedizolid as a potential treatment option for Nocardia infections.

Nocardiosis from 1888 to 2017

The genus Nocardia is an aerobic bacterium, Gram-positive and catalase positive that is in Nocardiaceae family. This bacterium first described by Edmond Nocard in 1888 and is not in human commensal bacteria. To date, nocardiosis incidence is increasing due to increase population growth rate, increase in patients with immune disorder diseases and immunocompromised patients. We surveyed taxonomic position, isolation methods, phenotypic and molecular identification at the genus and species levels, antibiogram, treatment and epidemiology in the world from 1888 to 2017.

Severe pneumonia due to Nocardia otitidiscaviarum identified by mass spectroscopy in a cotton farmer: A case report and literature review

RATIONALE

Nocardia species are aerobic saprophytic bacilli. Among Nocardia species, Nocardia otitidiscaviarum (N otitidiscaviarum) is rarely reported in pulmonary infection.

PATIENT CONCERNS

We reported a case of N otitidiscaviarum pneumonia in a cotton farmer.

DIAGNOSES

N otitidiscaviarum pneumonia was identified by mass spectroscopy.

INTERVENTIONS

Combined treatments (amikacin, imipenem and trimethoprim-sulfamethoxazole) were administered after identification of N otitidiscaviarum.

OUTCOMES

The patient eventually died from severe respiratory insufficiency in the hospital.

LESSONS

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

Nocardiosis in the south of France over a 10-years period, 2004-2014

BACKGROUND

Nocardiosis is a rare disease with polymorphic presentations. The epidemiology and clinical presentation could change with the increasing number of immunocompromised patients.

METHODS

The medical records and microbiological data of patients affected by nocardiosis and treated at the university hospitals of Marseille between 2004 and 2014 were analyzed retrospectively.

RESULTS

The cases of 34 patients infected by Nocardia spp during this period were analyzed. The main underlying conditions were transplantation (n=15), malignancy (n=9), cystic fibrosis (n=4), and immune disease (n=3); no immunodeficiency condition was observed for three patients. No case of AIDS was observed. At diagnosis, 61.8% had received steroids for over 3 months. Four clinical presentations were identified, depending on the underlying condition: the disseminated form (50.0%) and the visceral isolated form (26.5%) in severely immunocompromised patients, the bronchial form (14.7%) in patients with chronic lung disease, and the cutaneous isolated form (8.8%) in immunocompetent patients. Nocardia farcinica was the main species identified (26.5%). Trimethoprim-sulfamethoxazole was prescribed in 68.0% of patients, and 38.0% underwent surgery. Mortality was 11.7%, and the patients who died had disseminated or visceral nocardiosis.

CONCLUSIONS

The clinical presentation and outcome of nocardiosis depend on the patient's initial immune status and underlying pulmonary condition. Severe forms were all iatrogenic, occurring after treatments altering the immune system.

Linezolid for the Treatment of Patients with Central Nervous System Infection

Objective:

To review the available evidence regarding the use of linezolid for the treatment of patients with central nervous system (CNS) infections.

Data Sources:

Relevant studies were identified through searches of the PubMed, Current Contents, and Cochrane databases (publications archived until October 2006).

Study Selection and Data Extraction:

Case reports, case series, prospective and retrospective studies, and randomized controlled trials were eligible for inclusion in our review if they evaluated the effectiveness and safety of linezolid for the treatment of patients with CNS infections.

Data Synthesis:

In 18 (42.9%) of the 42 relevant cases identified, patients had undergone neurosurgical operations and/or had prosthetic devices. Meningitis was the most common CNS infection, accounting for 20 (47.6%) cases. Other CNS infections included brain abscesses (14; 33.3%), ventriculitis (5; 11.9%), and ventriculo-peritoneal shunt infection (3; 7.1%). In the 39 patients in whom the responsible pathogen was isolated, those predominantly responsible for the CNS infections were: penicillin–nonsusceptible Streptococcus pneumoniae (7; 17.9%), vancomycin-resistant enterococci (6; 15.4%), Nocardia spp. (5; 12.8%), methicillin-resistant Staphylococcus epidermidis (4; 10.3%), and methicillin-resistant Staphylococcus aureus (3; 7.7%). Of the 42 patients who received linezolid for the treatment of CNS infections, 38 (90.5%) were either cured or showed clinical improvement of the infection. The mean duration of follow-up was 7.2 months; no recurrent CNS infection was reported.

Conclusions:

The limited published data suggest that linezolid may be considered for the treatment of patients with CNS infections in cases of failure of previously administered treatment or limited available options.

LInezolid for the Treatment of Nocardia spp. Infections

Objective:

To review the available evidence regarding the use of linezolid for the treatment of Nocardia spp. infections.

Data Sources:

Data were identified through a search of MEDLINE (1966-May 2007), American Search Premier (1975-May 2007), International Pharmaceutical Abstracts (1960-2007), Science Citation Index Expanded (1996-2007), and Cochrane Databases (publications archived until May 2007) using the terms linezolid and Nocardia.

Study Selection and Data Extraction:

Prospective and retrospective studies, case reports, case series, and in vitro studies were eligible for inclusion if they used linezolid for nocardiosis regardless of site of infection and outcome.

Data Synthesis:

We identified 11 published cases of linezolid use for Nocardia spp. infections. The predominant species isolated were N. asteroides (n=4; 36%) and N. farcinica (n= 3; 27%). Nocardiosis with central nervous system involvement (n= 7; 64%) or disseminated disease (n= 4; 36%) were most common. The main reason for discontinuation of previous antimicrobials was most often related to adverse effects (n= 5; 45%), followed by clinical failure (n = 3; 27%). Linezolid was associated with cure or improvement in all cases (n =11; 100%). However, the majority of patients developed serious complications that may have led to premature discontinuation of therapy with linezolid, including myelosuppression (n = 5; 45%) or possible/confirmed peripheral neuropathy (n = 2; 18%).

Conclusions:

The limited published data suggest that linezolid appears to be an effective alternative to trimethoprim/sulfamethoxazole for the treatment of nocardiosis. Unfortunately, the high cost and potentially serious long-term toxicities of linezolid appear to limit its use and relegate it to salvage therapy alone or in combination with other antimicrobials.

Nocardiosis in ectopic ACTH syndrome: A case report and review of 11 cases from the literature

Ectopic adrenocorticotropic hormone (ACTH) syndrome (EAS) associated with nocardiosis is rare, and little information is available regarding its clinical characteristics. In this study, the case of a 35-year-old male patient who showed significant cushingoid features and had a cough with yellow phlegm for 1 month is described. Pulmonary computed tomography (CT) scanning and ¹⁸F-fluorodeoxyglucose positron emission tomography combined with CT identified two different lesions in the mediastinum and pulmonary region, respectively. The lesion in the mediastinum was finally diagnosed as an ACTH-secreting mediastinal paraganglioma via biopsy. The sputum culture confirmed pulmonary nocardiosis. The patient was effectively treated with complete tumor resection following the treatment of nocardiosis using trimethoprim-sulfamethoxazole. Following the present case, 11 additional cases of nocardiosis in EAS were identified in the literature and their clinical characteristics were compared and evaluated. It may be concluded that, although Nocardia remains a rare opportunistic infection pathogen in EAS, it is necessary to consider nocardiosis as a diagnosis for patients with pulmonary imaging findings of cavity, consolidation or nodule, particularly when there are brain and extra-pulmonary lesions as well as a poor response to regular treatment.