A fatal case of Nocardia otitidiscaviarum pulmonary infection and brain abscess: taxonomic characterization by molecular techniques

Introduction: Nocardia otitidiscaviarum is a rare cause of human infections, mostly causing cutaneous and lymphocutaneous infections of mild severity. We report two cases of fatal pulmonary infection caused by Nocardia otitidiscaviarum in elderly patients. Methodology: Case 1: A 70-year old woman presented with fever and cough with expectoration for a month. On physical examination, she had tachypnea and inspiratory crepitations in bilateral basal regions. Case 2: A 74-year old man presented with productive cough with foul smelling expectoration, fever and shortness of breath for one week. On examination, he had tachypnea, bilateral wheezing and inspiratory crepitations. In both cases, sputum was sent to microbiology laboratory. On direct microscopy Gram-positive, finely branching filaments were observed which were acid fast with 1% sulphuric acid. Chalky white opaque wrinkled colonies with musty basement type odour were seen on blood agar. Both patients were treated empirically with trimethoprim-sulfamethoxazole for Nocardia infection after notification of microscopy findings however both expired on Day 2 and Day 5 of admission, respectively. Both isolates were susceptible to amikacin, linezolid, ciprofloxacin and gentamicin. They were resistant to trimethoprim-sulfamethoxazole, ampicillin, amoxicillin-clavulanic acid, erythromycin, and imipenem. Based on biochemical identification and antimicrobial susceptibility pattern, the organism was identified as Nocardia otitidiscaviarum. The identification was confirmed using MALDI-TOF (Vitek MS, Biomerieux, France). Conclusion: Our report highlights the importance of early identification of Nocardia to species level to improve treatment outcomes especially in critically ill patients. Mass spectrometry can become an integral part of diagnostic algorithms for nocardiosis.

Download Full-text

Case 28

Oxford Case Histories in Infectious Diseases and Microbiology ◽

10.1093/med/9780198846482.003.0028 ◽

2020 ◽

pp. 186-192

Author(s):

Hilary Humphreys

Keyword(s):

T Cell ◽

Brain Abscess ◽

Human Disease ◽

Ornamental Fish ◽

Molecular Techniques ◽

Burr Hole ◽

High Dose ◽

Laboratory Confirmation ◽

Disseminated Disease ◽

The Brain

Nocardia are opportunist pathogens, especially affecting patients with T-cell deficiencies, such as those on prolonged high-dose corticosteroids. They are found in the environment, associated with ornamental fish, and Nocardia asteroids complex is most commonly associated with human disease. Infection may result in a brain abscess, pulmonary infection, or disseminated disease including involvement of the skin. Steriotactic aspiration or via a burr hole to obtain a sample are replacing open craniotomy, unless the brain abscess is large. Previously, laboratory confirmation was dependant on prolonged culture and stains for acid-and alcohol-fact bacilli, but increasingly, molecular techniques are used to diagnose this and other causes of brain abscess. Consensus and clinical experience suggest that co-trimoxazole with or without a carbapenem, are the initial empiric anti-infectives of choice for nocardiosis. Susceptibility testing should be carried out on available isolates as treatment is usually for 6 months or longer.

Download Full-text

781. Non-Tuberculous Mycobacterium: Often a Missed Entity

Open Forum Infectious Diseases ◽

10.1093/ofid/ofy210.788 ◽

2018 ◽

Vol 5 (suppl_1) ◽

pp. S280-S280

Author(s):

Sairam B ◽

Atul Gogia ◽

Atul Kakar ◽

S P Byotra

Keyword(s):

Pulmonary Infection ◽

Clinical Presentation ◽

Mycobacterial Infection ◽

Molecular Techniques ◽

Drug Resistant ◽

First Line ◽

Diagnostic Dilemma ◽

Mycobacterial Diseases ◽

Back Ache ◽

Anti Tubercular Therapy

Abstract Background Initially referred to as Lady Windermere syndrome, the prevalence of Non-Tuberculous Mycobacterium (NTM) is on the rise globally. In India, the TB capital of the world, these infections still go unrecognized, as the clinical presentation of all mycobacterial diseases are similar. This is of clinical relevance as misdiagnosis may lead to unwarranted or inappropriate therapy. Methods We conducted a retrospective study of adults suspected of having mycobacterial infection. Records of patients admitted with suspected TB from January 2015 to December 2017 were reviewed; clinicoradiological features were correlated with the organism isolated; treatment given and outcomes were recorded. Results Out of 877 suspected patients, 245 patients had microbiologically proven Mycobacterium tuberculosis and 34 had NTM (3.8%). Pulmonary infection was seen in 19 cases (56%), rest were extra pulmonary (34%). Fever was the commonest symptom (62%) others being cough (50%), breathlessness (41%), hemoptysis (15%), weight loss (3%), chest pain (3%), and back ache (12%). Symptoms were prolonged (>1 month) in 65% of cases. Radiologically, cavitations (42%), lung nodules (32%), and infiltrates (32%) were commonly seen. Upper zone predilection was noted in 68% of cases. Past tuberculosis was the major risk factor seen in 42% of cases while 26% were immunocompromised. Macrolide resistance was noted in none of our patients. Twenty-four out of 34 cases were AFB smear positive (71%), but MTB gene Xpert was negative. Our series includes four patients who did not respond to first-line anti-tubercular therapy (ATT) and were suspected to have multi-drug-resistant (MDR) tuberculosis. Cultures later grew NTM and the patients improved with macrolide regime. Conclusion NTM is an underreported infection in a developing country like India with a high TB prevalence. Similar clinical features and morphology create a greater diagnostic dilemma. Usage of molecular techniques and AFB culture should be made mandatory in all suspected cases of tuberculosis. NTM should always be considered in ATT nonresponders before starting them on MDR regime. Disclosures All authors: No reported disclosures.

Download Full-text

Mycobaterium fortuitum disseminated infection in an immunocompetent patient without predisposing factors

BMJ Case Reports ◽

10.1136/bcr-2020-235842 ◽

2020 ◽

Vol 13 (9) ◽

pp. e235842

Author(s):

Stephanie d'Incau ◽

Maria-Isabel Vargas ◽

Alexandra Calmy ◽

Jean-Paul Janssens

Keyword(s):

Risk Factors ◽

Pulmonary Infection ◽

Skin Lesions ◽

Immunocompetent Patient ◽

Definitive Diagnosis ◽

Optimal Treatment ◽

Molecular Techniques ◽

Surgical Removal ◽

Mycobacterium Fortuitum ◽

Direct Inoculation

Most Mycobacterium fortuitum infections described involve direct inoculation through skin lesions. We describe the case of a patient without risk factors who presented with an intracranial mass and a pulmonary infection with M. fortuitum. As M. fortuitum are rarely pathogens, there is little knowledge about the optimal treatment and outcome of such infections: what is the best mode of administration, what is the best therapy duration and is surgery always required are some of the unanswered questions. In our patient, surgical removal of the mass associated with a 1-year antimycobacterial therapy led to a full recovery. Even though M. fortuitum was rapidly identified in sputum, it was initially considered non-pathogenic and the definitive diagnosis required almost 6 weeks of investigations. New molecular techniques will probably lead to more identifications of M. fortuitum in the next few years and a better knowledge of their possible pathogenicity and optimal treatment.

Download Full-text