A Case of Cutaneous Nocardiosis with Involvement of the Trachea, Anterior Mediastinum and Sternum

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.

Nocardia colli sp. nov., a new pathogen isolated from a patient with primary cutaneous nocardiosis

A novel nocardioform strain, CICC 11023^T, was isolated from a tissue biopsy of neck lesions of a patient with primary cutaneous nocardiosis and characterized to establish its taxonomic position. The morphological, biochemical, physiological and chemotaxonomic properties of strain CICC 11023^T were consistent with classification in the genus Nocardia. Whole-cell hydrolysates were rich in meso-diaminopimelic acid, galactose, arabinose and fructose. Mycolic acids were present. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, one unidentified phospholipid and two unidentified lipids, and the predominant menaquinone was cyclo MK-8 (H4, ω-cyclo). The main fatty acids (>5 %) were C_18 : 0 10-methyl (TBSA), C_16 : 0, summed feature 4 (C_16 : 1 trans 9/C_15 : 0 iso 2OH), C_15 : 0 and C_17 : 0 10-methyl. Phylogenetic analyses based on 16S rRNA gene sequences revealed that the isolate is most closely related (>98 % similarity) to the type strains Nocardia ninae OFN 02.72^T, Nocardia iowensis UI 122540^T and Nocardia alba YIM 30243^T, and phylogenetic analysis of gyrB gene sequences showed similarity (89.1–92.2 %) to Nocardia vulneris NBRC 108936^T, Nocardia brasiliensis IFM 0236^T and Nocardia exalbida IFM 0803^T. DNA–DNA hybridization results for strain CICC 11023^T compared to Nocardia type strains ranged from 20.4 to 35.4 %. The genome of strain CICC 11023^T was 8.78 Mbp with a G+C content of 67.4 mol% overall. The average nucleotide identity (ANI) values between strain CICC 11023^T and N. alba YIM 30243^T were low (OrthoANIu=77.47 %), and the ANI values between strain CICC 11023^T and N. vulneris NBRC 108936 ^T were low (OrthoANIu=83.75 %). Consequently, strain CICC 11023^T represents a novel Nocardia species on the basis of this polyphasic study, for which the name Nocardia colli sp. nov. is proposed. The type strain is CICC 11023^T (=KCTC 39837^T).

Madurella mycetomatis infection of the foot: a case report of a neglected tropical disease in a non-endemic region

Background

Mycetoma is an uncommon chronic granulomatous infection of cutaneous and subcutaneous tissues that can be caused by filamentous bacteria (actinomycetoma) or fungi (eumycetoma). It is the prerogative of young men between the third and fourth decade and is transmitted through any trauma causing an inoculating point. The classic clinical triad associates a painless hard and swelling subcutaneous mass, multiple fistulas, and the pathognomonic discharge of grains. Although endemic in many tropical and subtropical countries, mycetoma can also be found in non-endemic areas as in Morocco, and causes then diagnosis problems leading to long lasting complications. Therefore, we should raise awareness of this neglected disease for an earlier management. Under medical treatment however, mycetoma has a slow healing and surgery is often needed, and relapses are possible.

Case presentation

Herein we report a case of a 64 years old patient, with a history of eumycetoma occurring ten years ago treated with oral terbinafine coupled with surgery. A complete remission was seen after 2 years. He presented a relapse on the previous scar 6 months ago. There wasn’t any bone involvement in the magnetic resonance imaging (MRI). The patient was put under oral terbinafine with a slow but positive outcome.

Conclusion

Through this case report, we perform a literature review and highlight the importance of increase awareness of mycetoma in clinical practice especially in non-endemic regions.

Mycetoma in China: A Case Report and Review of the Literature

Mycetoma is a chronic granulomatous infectious disease that can affect the skin, subcutaneous tissue, fascia and bone. It can be caused by filamentous bacteria or fungi and usually involves the legs and feet. Mycetoma is endemic in tropical and subtropical regions and is easily misdiagnosed in clinical practice because of its nonspecific clinical features and lack of awareness of the disease. Although mycetoma is very rare in mainland China, an increasing number of cases have been reported in recent years. Here, we report a case of mycetoma in a patient who was misdiagnosed many years before receiving the correct treatment, leading to disease progression and motion limitation. The grains that represent microorganismal colonies were important clues for diagnosis. We also reviewed reported cases of mycetoma in mainland China. The majority of cases were reported from southern regions. Actinomycetoma was more commonly reported than was eumycetoma. The causative agents of actinomycetoma included Nocardia brasiliensis, N. asteroides, N. otitidiscaviarum, N. ninae and Gordonia terrae, and the causative fungi of eumycetoma were identified as Madurella mycetomatis, Fonsecaea pedrosoi and Acremonium falciforme. Notably, the diagnosis of mycetoma was delayed from months to decades in all of the patients, likely due to a lack of clinical experience. Our literature review suggests the importance of increased awareness of mycetoma in clinical practice, especially in non-endemic regions. Further investigative studies are needed to determine the real incidence of the disease in China.