Clinical manifestations of nocardiosis: Study of risk factors and outcomes in a tertiary care hospital

A Diagnostic Challenge: A Case of Disseminated Nocardiosis Presenting With Generalized Lymphadenopathy in a Patient With Interleukin-12 Deficiency

Deficiency in interleukin-12 (IL-12) can result in susceptibility to opportunistic infection, with IL-12 deficiency being a rare genetic cause. Nocardia farcinica is a gram-positive aerobic actinomycete that can cause disseminated and potentially lethal nocardiosis in immunocompromised patients. This report describes a 16-year-old male adolescent with IL-12 deficiency presenting with generalized lymphadenopathy due to disseminated Nocardia farcinica. The subject of our study is a male adolescent who exhibited clinical manifestations consistent with cholestasis. He underwent extensive workup for malignancy, suspecting cholangiocarcinoma initially. The workup turned out unremarkable, and later during his hospital stay, he deteriorated and required intensive care unit (ICU) admission, as he developed superior vena cava (SVC) syndrome from massive enlargement of mediastinal and cervical lymph nodes. During the patient's admission, it was found that he had a deficiency of interleukin-12 (IL-12). Later on, a blood culture revealed the presence of Nocardia farcinica species. Subsequently, the patient was initiated and improved drastically on an empirical antibiotic regimen consisting of amikacin, co-trimoxazole, meropenem, and moxifloxacin. Following that, the susceptibility results came out, and he was switched to oral co-trimoxazole and oral moxifloxacin as he no longer required inpatient care. This report highlights the importance of accurate diagnosis of causes of immunosuppression and early investigation, diagnosis, and management of potentially fatal opportunistic infections such as disseminated Nocardia farcinica.

Brain Abscess Caused by Nocardia brevicatena in an Immunocompetent Patient: A Case Report

Nocardia brain abscess is relatively rare and generally occurs in immunodeficient patients. Here, we present the first case of brain abscess due to Nocardia brevicatena in an immunocompetent patient, with unknown origin. In this case, a 49-year-old man was admitted to our hospital with limb twitching and complained of a history of intermittent headache. He was diagnosed with brain abscess through brain imaging and cured after craniotomy for abscess excision and targeted antibiotic treatment. Surgical specimens were sent for further detection. The causative organism was identified by weak acid-fast staining, culture and metagenomic next-generation sequencing (mNGS). We hope this case could provide a reference for incoming patients as well as their clinical management.

A Complete Genome of Nocardia terpenica NC_YFY_NT001 and Pan-Genomic Analysis Based on Different Sources of Nocardia spp. Isolates Reveal Possibly Host-Related Virulence Factors

OBJECTIVE

We aimed to identify the possible virulence genes associated with Nocardia NC_YFY_NT001 isolated by ourselves and other Nocardia spp.

METHODS

The genome of Nocardia terpenica NC_YFY_NT001 was completed by using PacBio and Illumina platforms. A pan-genomic analysis was applied to selected complete Nocardia genomes.

RESULTS

Nocardia terpenica NC_YFY_NT001 can cause healthy mice death by tail intravenous injection. The genome of NT001 has one circular chromosome 8,850,000 bp and one circular plasmid 70,000 bp with ~68% GC content. The chromosome and plasmid encode 7914 and 80 proteins, respectively. Furthermore, a pan-genomic analysis showed a total of 45,825 gene clusters, then 304 core, 21,045 shell and 24,476 cloud gene clusters were classified using specific parameters. In addition, we found that catalases were more abundant in human isolates. Furthermore, we also found no significant differences in the MCE proteins between different strains from different sources. The pan-genomic analysis also showed that 67 genes could only be found in humoral isolates. ReX3 and DUF853 domain protein were found in all eight human isolates. The composition of unique genes in humoral isolate genomes indicated that the transcriptional regulators may be important when Nocardia invades the host, which allows them to survive in the new ecological system.

CONCLUSION

In this study, we confirmed that NT001 could cause infected animal death, and identified many possible virulence factors for our future studies. This study also provides new insight for our further study on Nocardia virulence mechanisms.

A ten-year retrospective analysis of nocardiosis in a tertiary care center of South-coastal India

Nocardiosis is an uncommon life-threatening infection caused by Nocardia spp. This study aimed to review the distribution of risk factors, clinical characteristics, microbiological findings, treatment and outcome of patients diagnosed with nocardiosis. This study was a retrospective case record review of all nocardiosis cases that were diagnosed at our tertiary care hospital from January 2008 to December 2019. A total of 48 patients with a mean age of 52.2±16.28 years were included. Out of which forty one (85%) were diagnosed as pulmonary nocardiosis and seven (14.6%) as disseminated disease. Chronic lung disease 25 (52.1%), long term steroid use 22 (45.8%) followed by diabetes mellitus 11 (22.9%) were common predisposing factors. The common symptoms were fever (87.5%), cough (79.2%) and breathlessness (52.1%). The most frequent radiologic finding included consolidation in 38 (79.1%), cavitation with thickened wall in 2 (4.1%), reticulonodular shadows in 2 (4.1%), and unilateral pleural effusion in 5 (10.4%). Nocardia otitidiscaviarum (22.9%) was frequently isolated from cultures. Resistance to trimethoprim-sulfamethoxazole (TMP-SMX) was observed in 21% cases. Mortality was noted in 6 (12.5%) patients and all were with pulmonary involvement. The percentage of death among those with and without pulmonary tuberculosis was 33.3% and 5% respectively. Patients affected by pulmonary nocardiosis with previous history of pulmonary tuberculosis showed significant association with poor outcome (p-value=0.05). In conclusion, nocardiosis mainly affects patients with structural lung disease or immunocompromised hosts with adverse outcome. Awareness of this infection is crucial for a clinician, and any suspicion should lead to make an early diagnosis and choose an appropriate empirical treatment to improve the outcome in this population.

Localized Pulmonary Nocardia farcinica Infection As the Presenting Symptom of Acquired Immunodeficiency Syndrome

Nocardiosis is an opportunistic infection that most commonly affects immunocompromised patients, with clinical presentations ranging from localized to disseminated disease. In the United States, the reported incidence is approximately 500 to 1,000 cases per year, with an observed male-to-female predominance of 3:1. We present the case of a 37-year-old male with a past medical history of malaria who presented with watery, non-bloody diarrhea for four days associated with a fever for two weeks. The human immunodeficiency virus (HIV) was positive in the emergency room before admission. Computerized tomography (CT) of the chest with contrast revealed an irregular pleural base mass in the right lower lobe with several small air foci. CT of the abdomen and pelvis revealed the right pleural base lung mass to be adherent to the diaphragm, as well as mild splenomegaly. The cluster of differentiation 4 (CD4) count was 9 cells/mm³. An acid-fast bacilli (AFB) sputum culture was positive for Nocardia farcinica. Trimethoprim-sulfamethoxazole was started for a Nocardia farcinica pulmonary infection, in addition to antiretroviral therapy. The patient was strongly encouraged to follow-up at the outpatient department.

Nocardia Infections: Ten Years Experience from a Tertiary Health Care Center in North India (2007-2016)

BACKGROUND

Nocardia species are important cause of infections in humans but are underreported due to missed diagnosis as well as misdiagnosis. Majority of the literature on these infections consists of case reports or series with few articles describing high number of cases.

OBJECTIVE

To study the epidemiology of Nocardia infections in a tertiary care center.

MATERIALS AND METHODS

This retrospective observational study was done in a tertiary care centre of North India over a period of 10 years (2007-2016). The detection of Nocardia spp. from clinical specimens was done by conventional methods viz. direct microscopy (Gram's stain, modified Ziehl -Neelsen stain [1%], KOH examination) and culture.

RESULTS

A total of 25 cases of nocardiosis were diagnosed during the study period. The mean age of the patients was 50.9 years (range 30-72 years) with a male:female ratio of 3:2. The site of disease in these patients included pulmonary (n=18), cutaneous (n=4), perinephric abscess (n=1), ocular (n=1) and bone (n=1). Risk factors associated were underlying lung disease (n=11), smoking (n=7), diabetes (n=5) and steroid therapy (n=4) in pulmonary nocardiosis, iatrogenic (n=1) and leprosy (n=1) in cutaneous nocardiosis, diabetes in perinephric abscess and cataract surgery in ocular nocardiosis. Culture was positive in 12/25 (48%) patients for Nocardia spp. Direct microscopy was positive in 22 patients. We wish to highlight that meticulous observation of KOH wet mount examination helped in clinching the diagnosis of Nocardiosis in 3 cases which were earlier missed by other methods.

CONCLUSION

Good communication with the clinician alongside a meticulous effort in the laboratory is essential for appropriate diagnosis and management of these cases.

Nocardiosis: A Neglected Disease

Nocardiosis is a neglected tropical disease. It has varied geographical presence and a spectrum of clinical presentations. This review aims to focus on the epidemiology of nocardial infections with a systematic approach to their diagnosis and treatment. Nocardiacauses chronic infections and ailments, and may remain cryptic but progressive in its course. Unless suspected, diagnosis can be easily missed resulting in increased morbidity and mortality. Thorough knowledge of local epidemiology, demography, clinical course and presentation, diagnostic modalities, and antibiotic susceptibility patterns of the prevalent Nocardia species is essential to curb spread of this infection. This is a systematic review in which internet search has been done for citation indices (Embase, PubMed, Ovid, and other individual journals) till March 2020 utilizing the following key words "Nocardia," "taxonomy," "prevalence," "clinical features," "diagnosis," "treatment," and "susceptibility." We selected a total of 87 review articles, case series, and case reports all in English language.

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.