Nocardia Infection in Nephrotic Syndrome Patients: Three Case Studies and A Systematic Literature Review.

OBJECTIVE: The multicenter literature review and case studies of 3 patients were undertaken to provide an updated understanding of nocardiosis, an opportunistic bacterial infection affecting immunosuppressed nephrotic syndrome (NS) patients receiving long-term glucocorticoid and immunosuppressant treatment. The results provided clinical and microbiological data to assist physicians in managing nocardiosis patients. METHODS: Three cases between 2017 and 2018 from a single center were reported. Additionally, a systematic review of multicenter cases described in the NCBI PubMed, Web of Science, and Embase in English between January 1, 2001 and May 10, 2021 was conducted. RESULTS: This study described three cases of Nocardia infection in NS patients. The systematic literature review identified 24 cases with sufficient individual patient data. A total of 27 cases extracted from the literature review showed that most patients were > 50 years of age and 70.4% were male. Furthermore, the glucocorticoid or corticosteroid mean dose was 30.9 ± 13.7 mg per day. The average time between hormone therapy and Nocardia infection was 8.5 ± 9.7 months. Pulmonary (85.2%) and skin (44.4%) infections were the most common manifestations in NS patients, with disseminated infections in 77.8% of patients. Nodule/masses and consolidations were the major radiological manifestations. Most patients showed elevated inflammatory biomarkers levels, including white blood cell counts, neutrophils percentage, and C-reactive protein. Twenty-five patients received trimethoprim-sulfamethoxazole monotherapy (18.5%) or trimethoprim-sulfamethoxazole-based multidrug therapy (74.1%), and the remaining two patients (7.4%) received biapenem monotherapy. All patients, except the two who were lost to follow-up, survived without relapse after antibiotic therapy. CONCLUSIONS: Nephrotic syndrome patients are at high risk of Nocardia infection even if receiving low-dose glucocorticoid during the maintenance therapy. The most common manifestations of nocardiosis in NS patients include abnormal lungs revealing nodules and consolidations, skin and subcutaneous abscesses. The NS patients have a high rate of disseminated and cutaneous infections but a low mortality rate. Accurate and prompt microbiological diagnosis is critical for early treatment, besides the combination of appropriate antibiotic therapy and surgical drainage when needed for an improved prognosis.

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.

Left thigh phlegmon caused by Nocardia farcinica identified by 16S rRNA sequencing in a patient with leprosy: a case report.

BACKGROUND: In recent years, Nocardia farcinica has been reported to be an increasingly frequent cause of localized and disseminated infections in the immunocompromised patient. However, recent literature is limited. We report a case of left thigh phlegmon caused by N. farcinica that occurred in a patient with leprosy undergoing treatment with prednisone for leprosy reaction. CASE PRESENTATION: We describe the case of left thigh phlegmon caused by Nocardia farcinica in a 54-year-old Italian man affected by multi-bacillary leprosy. The patient had worked in South America for 11 years. Seven months after his return to Italy, he was diagnosed with leprosy and started multi-drug antibiotic therapy plus thalidomide and steroids. Then, during therapy with rifampicin monthly, minocycline 100 mg daily, moxifloxacin 400 mg daily, and prednisone (the latter to treat type 2 leprosy reaction), the patient complained of high fever associated with erythema, swelling, and pain in the left thigh. Therefore, he was admitted to our hospital with the clinical suspicion of cellulitis. Ultrasound examination and Magnetic Resonance Imaging showed left thigh phlegmon. He was treated with drainage and antibiotic therapy (meropenem and vancomycin replaced by daptomycin). The responsible organism, Nocardia farcinica, was identified by 16S rRNA sequencing in the purulent fluid taken out by aspiration. The patient continued treatment with intravenous trimethoprim/sulfamethoxazole and imipenem followed by oral trimethoprim/sulfamethoxazole and moxifloxacin. A whole-body computed tomography did not reveal dissemination to other organs like the lung or brain.The patient was discharged after complete remission. Oral therapy with trimethoprim/sulfamethoxazole, moxifloxacin, rifampicin monthly, clofazimine and thalidomide was prescribed to be taken at home. One month after discharge from the hospital the patient is in good clinical condition with complete resolution of the phlegmon. CONCLUSION: N. farcinica is a rare infectious agent that mainly affects immunocompromised patients. Presentation of phlegmon only without disseminated infection is unusual, even in these kinds of patients. In any case, a higher index of suspicion is needed, as diagnosis can easily be missed due to the absence of characteristic symptoms and the several difficulties usually encountered in identifying the pathogen.

Sporotrichoid nocardiosis with cutaneous dissemination.

Dissemination of primary cutaneous nocardiosis is a rare event. A 37-year-old man working as farmer presented with multiple painful suppurative nodular and ulcerative skin lesions over left lower extremities, in a linear pattern, with duration of five months and single painful nodule over right elbow since last three months. We found the presence of beaded filamentous bacteria in Gram stain smear and partial acid fast stain, from the smear taken from pus. Patient responded well to cotrimoxazole therapy. Hence, we confirm our diagnosis of sporotrichoid pattern of cutaneous nocardiosis with dissemination to other cutaneous area.

Nocardial mycetoma: diverse clinical presentations.

Nocardia spp are gram-positive, aerobic, acid-fast bacteria which exist as saprophytes in nature. Invasive disseminated infections are particularly common in immunocompromised or debilitated hosts. Superficial infections with Nocardia spp occur as a result of local trauma and contamination of the wound. Clinically, it presents as acute infection (abscesses or cellulitis), mycetoma, or sporotrichoid infection. Differential diagnosis includes eumycetoma, chromomycosis, blastomycosis, coccidioidomycosis, sporotrichosis, tuberculosis, botryomycosis, syphilis, yaws, and neoplasia. Its diagnosis is confirmed by demonstrating the causative organism in exudates (as granules), tissue specimens, or cultures. Early diagnosis will obviate need for drastic surgical measures as early institution of chemotherapy is effective in most patients. However, its diagnosis is often delayed due to diverse clinical presentations and for want of clinical suspicion, particularly in non-endemic areas. This paper presents 4 clinical forms of this not so uncommon disease, emphasizing the importance of high index of clinical suspicion, especially in non-endemic regions; and the significance of repeated examination of exudates for Nocardia granules for an early diagnosis.

Nocardia farcinica pleuritis in a lepromatous patient with severe necrotizing reaction: an unusual presentation.

A young, male, lepromatous leprosy patient with a severe necrotizing erythema nodosum leprosum reaction treated with prolonged oral steroids and thalidomide developed pleuritis that was caused by a rare opportunistic pathogen, Nocardia farcinica. This organism was resistant to most antibiotics but was susceptible to amikacin and minocycline. During the course of treatment the patient developed severe gastritis which necessitated the removal of clofazimine and the inclusion of an H2 receptor antagonist. Bilateral steroid-induced cataracts needed surgical correction. This case is being presented for its rare opportunistic bacterial infection and for the multiple complications which made treatment difficult.

Nocardia species as an etiologic agent in Parkinson's disease: serological testing in a case-control study.

To test the hypothesis that Nocardia spp. may be an etiologic factor in Parkinson's disease (PD), we used a serodiagnostic panel to determine if PD patients had antibodies specific for Nocardia spp. To validate the serological test panel, sera from healthy volunteers and from patients with culture-proven nocardiosis (n = 307) were compared in part 1 of the study. The sensitivity of the panel was 88% for detection of culture-proven nocardial infections, and specificity was 85% (excluding cross-reactive leprosy cases). In part 2, no difference in seropositivity was found when PD patients were compared with their age- and gender-matched controls (n = 140). We found a high exposure rate of humans to nocardial antigens, especially among men and older individuals. Our results offer no support to the hypothesis that Nocardia spp. are causative in PD; however, it is possible that serological testing may not be optimal for detection of nocardial central nervous system infection.

Enzyme-linked immunosorbent assay for serological diagnosis of Nocardia brasiliensis and clinical correlation with mycetoma infections.

We previously identified three immunodominant antigens obtained from a Nocardia brasiliensis cell extract and recognized by sera from mycetoma patients (M. C. Salinas-Carmona, L. Vera, O. Welsh, and M. Rodríguez, Zentralbl. Bakteriol. 276:390-397, 1992). In the present work, we obtained a crude extract from a mass culture of N. brasiliensis HUJEG-1 and purified two immunodominant antigens, the 26- and 24-kDa proteins, by using simple physiochemical techniques. With these antigens, we developed a conventional solid-phase enzyme-linked immunosorbent assay and tested 30 serum samples from mycetoma patients, 29 from tuberculosis patients, 24 from a leprosy group, and 31 from healthy individuals. Our results show for the first time statistically significant differences in serology among these groups. All mycetoma patients with a positive culture for N. brasiliensis had absorbance values higher than 0.3. On the other hand, the mycobacterium-infected patients as well as the healthy individuals all had absorbance values below that level. Moreover, we found a close correlation between the clinical condition of the mycetoma patients and the anti-26- and anti-24-kDa protein antibody concentrations. We therefore propose the use of this assay in routine clinical laboratories to confirm the diagnosis of N. brasiliensis infection in human mycetoma cases. In addition, the possible application of this assay in the serodiagnosis of Nocardia asteroides infection is also discussed.

Immunodiagnosis of nocardiosis.

A specific immunodominant 54-kDa antigen was purified from a culture filtrate of Nocardia asteroides by immunoaffinity chromatography. The chromatography column was prepared with immunoglobulin G obtained from sera from patients with lepromatous leprosy. Unbound solutes consisted of specific, partially purified N. asteroides antigens, primarily a 54-kDa band, accompanied by two others of 31 and 62 kDa. The Western blot (immunoblot) technique was applied to detecting the immunologic response to nocardiae in the serum of nocardiosis patients. Each of the serum samples from immunosuppressed or immunocompetent patients infected with N. asteroides reacted with the 54-kDa band, and two reacted with the 31- and 62-kDa bands. There was no reaction to either the 54- or the 31-kDa antigen with all serum samples obtained from patients with tuberculosis, except for one, with all serum samples obtained from patients with leprosy, or with all sera obtained from healthy controls. The partially purified 54-kDa antigen, specific for N. asteroides, was used as the immunogen to generate monoclonal antibodies (mAbs) and two mAbs were selected. As determined by Western blot, both mAbs reacted with the 54-kDa band. Using indirect immunofluorescence or enzyme immunoassay with whole N. asteroides micro-organisms, the mAbs did not react with N. asteroides cells. No cross-reactivity with mycobacterial antigens, either culture-filtrate antigens or tuberculin, was exhibited with any of the two mAbs. These mAbs are candidates to be used for the development of a sensitive and specific diagnostic test for nocardiosis.

Use of partially purified 54-kilodalton antigen for diagnosis of nocardiosis by Western blot (immunoblot) assay.

A Western blot (immunoblot) assay is presented for the diagnosis of nocardiosis with a specific immunodominant 54-kilodalton (kDa) antigen purified from a culture filtrate of Nocardia asteroides by immunoaffinity chromatography. The chromatography column was prepared with immunoglobulin G obtained from sera from patients with lepromatous leprosy. Unbound solutes consisted of specific, partially purified N. asteroides antigens, primarily a 54-kDa band, accompanied by two others of 31 and 62 kDa. The Western blot technique was applied to detecting the immunologic response to nocardiae. Immunodetection was performed according to the biotin-avidin system, which greatly improved the detection of antibodies even in immunosuppressed hosts. Each of 16 serum samples from immunosuppressed or immunocompetent patients infected with N. asteroides reacted with the 54-kDa band, and two reacted with the 31- and 62-kDa bands. Each of the serum specimens obtained from patients with mycetoma caused by Nocardia brasiliensis or Rhodococcus rhodochrous reacted with the 54-kDa band. There was no reaction to either the 54- or the 31-kDa antigen with all serum samples obtained from patients with tuberculosis, except one, with all serum samples obtained from patients with leprosy, or with all sera obtained from healthy controls. The 54-kDa protein is a candidate to be used as a probe to study the humoral immunologic response to nocardiae.

Complement fixation antibody test for human nocardiosis.

Complement-fixing antibody was detected in 13 of 16 patients with histological and/or culture evidence of infection with Nocardia species. The antigen used was a filtrate of soluble substances secreted into liquid growth medium by cultures of N. asteroides. Apparent false positives reactions were found in three of three patients with leprosy and two of five patients with tuberculosis--results similar to some previously reported methods. N. asteroides and mycobacteria share antigens. Only the false positives with tuberculosis are considered a diagnostic problem. No reactions were obtained with sera from 26 patients with other infections and 41 unifected individuals. Whereas previous nocardia serodiagnostic methods have a sensitivity of approximately 50%, our overall sensitivity (81%) compares favorably and included 9 of 11 positive tests in immunocompromised nocardiosis patients (a source of false negative reactions with previous methods).