Canine Leproid Granuloma (CLG) Caused by Mycobacterial Species Closely Related to Members of Mycobacterium Simiae Complex in a Dog in Brazil.

This report describes the clinical features and molecular diagnosis of a case of canine leproid granuloma (CLG) caused by mycobacterial strains of the Mycobacterium simiae complex in Brazil. A 12-year-old non-neutered male Labrador Retriever dog was presented with a 2-week history of progressive painless cutaneous lesions. Ulcerated nodules with hematic crusts were observed on the dorsal surface of the right and left pinna and on the metacarpal, metatarsal, and digits. Complete blood count, serum biochemistry, aspiration cytology of cutaneous lesions, biopsy for histopathological evaluation, culture for aerobic and anaerobic bacteria, polymerase chain reaction and DNA sequencing to identify mycobacterial species were performed. According to the clinical and histopathological findings, a diagnosis of CLG was established. Despite the negative result of the bacterial culture, mycobacterial identification was made by sequencing the hsp65 gene. Our findings highlight that mycobacterial species closely related to members of the M simiae clade can be causative agents of CLG.

Genomic Degeneration and Reduction in the Fish Pathogen Mycobacterium shottsii.

Mycobacterium shottsii is a dysgonic, nonpigmented mycobacterium originally isolated from diseased striped bass (Morone saxatilis) in the Chesapeake Bay, USA. Genomic analysis reveals that M. shottsii is a Mycobacterium ulcerans/Mycobacterium marinum clade (MuMC) member, but unlike the superficially similar M. pseudoshottsii, also isolated from striped bass, it is not an M. ulcerans ecovar, instead belonging to a transitional group of strains basal to proposed "Aronson" and "M" lineages. Although phylogenetically distinct from the human pathogen M. ulcerans, the M. shottsii genome shows parallel but nonhomologous genomic degeneration, including massive accumulation of pseudogenes accompanied by proliferation of unique insertion sequences (ISMysh01, ISMysh03), large-scale deletions, and genomic reorganization relative to typical M. marinum strains. Coupled with its observed ecological characteristics and loss of chromogenicity, the genomic structure of M. shottsii is suggestive of evolution toward a state of obligate pathogenicity, as observed for other Mycobacterium spp., including M. ulcerans, M. tuberculosis, and M. leprae. IMPORTANCE Morone saxatilis (striped bass) is an ecologically and economically important finfish species on the United States east coast. Mycobacterium shottsii and Mycobacterium pseudoshottsii were originally described in the early 2000s as novel species from outbreaks of visceral and dermal mycobacteriosis in this species. Biochemical and genetic characterization place these species within the Mycobacterium ulcerans/M. marinum clade (MuMC), and M. pseudoshottsii has been proposed as an ecovar of M. ulcerans. Here, we describe the complete genome of M. shottsii, demonstrating that it is clearly not an M. ulcerans ecovar; however, it has undergone parallel genomic modification suggestive of a transition to obligate pathogenicity. As in M. ulcerans, the M. shottsii genome demonstrates widespread pseudogene formation driven by proliferation of insertion sequences, as well as genomic reorganization. This work clarifies the phylogenetic position of M. shottsii relative to other MuMC members and provides insight into processes shaping its genomic structure.

Mycobacterial skin infection.

PURPOSE OF REVIEW: The aim of this article is to review the most recent evidences concerning mycobacterial skin infections, limiting the period of literature research to 2020--2021. RECENT FINDINGS: Mycobacterial skin infections include a heterogeneous group of cutaneous diseases.Cutaneous tuberculosis is usually the result of hematogenous dissemination or spread from underlying foci and it must be distinguished from tuberculids, resulting from the immunological reaction to Mycobacterium tuberculosis antigens. Leprosy prevalence was drastically reduced after introduction of multidrug therapy in the 1980 s, but cases are still reported due to underdiagnosis, and animal and environmental reservoirs. Recent advances concentrate in the diagnostic field. Specific guidelines for the treatment of nontuberculous mycobacteria skin infections are missing and surgical procedures may be required. Prognosis is better as compared to nontuberculous mycobacteria lung disease. Rapid laboratory-confirmed diagnosis of Buruli ulcer may be achieved by the IS2404 PCR. Among new drugs, telacebec is promising in terms of potency, shorter duration and tolerability in animal studies. A clinical trial in humans is planned. SUMMARY: Mycobacterial cutaneous lesions are nonpathognomonic and clinical suspicion must be confirmed by culture or molecular detection. Long-course multidrug treatment is required based on susceptibility tests. Surgical intervention may also be required. Rehabilitation and psychosocial support reduce long-term physical and mental consequences mostly in Buruli ulcer and leprosy.

Progress of the Art of Macrophage Polarization and Different Subtypes in Mycobacterial Infection.

Mycobacteriosis, mostly resulting from Mycobacterium tuberculosis (MTb), nontuberculous mycobacteria (NTM), and Mycobacterium leprae (M. leprae), is the long-standing granulomatous disease that ravages several organs including skin, lung, and peripheral nerves, and it has a spectrum of clinical-pathologic features based on the interaction of bacilli and host immune response. Histiocytes in infectious granulomas mainly consist of infected and uninfected macrophages (Mφs), multinucleated giant cells (MGCs), epithelioid cells (ECs), and foam cells (FCs), which are commonly discovered in lesions in patients with mycobacteriosis. Granuloma Mφ polarization or reprogramming is the crucial appearance of the host immune response to pathogen aggression, which gets a command of endocellular microbe persistence. Herein, we recapitulate the current gaps and challenges during Mφ polarization and the different subpopulations of mycobacteriosis.

Host Immune-Metabolic Adaptations Upon Mycobacterial Infections and Associated Co-Morbidities.

Mycobacterial diseases are a major public health challenge. Their causative agents include, in order of impact, members of the Mycobacterium tuberculosis complex (causing tuberculosis), Mycobacterium leprae (causing leprosy), and non-tuberculous mycobacterial pathogens including Mycobacterium ulcerans. Macrophages are mycobacterial targets and they play an essential role in the host immune response to mycobacteria. This review aims to provide a comprehensive understanding of the immune-metabolic adaptations of the macrophage to mycobacterial infections. This metabolic rewiring involves changes in glycolysis and oxidative metabolism, as well as in the use of fatty acids and that of metals such as iron, zinc and copper. The macrophage metabolic adaptations result in changes in intracellular metabolites, which can post-translationally modify proteins including histones, with potential for shaping the epigenetic landscape. This review will also cover how critical tuberculosis co-morbidities such as smoking, diabetes and HIV infection shape host metabolic responses and impact disease outcome. Finally, we will explore how the immune-metabolic knowledge gained in the last decades can be harnessed towards the design of novel diagnostic and therapeutic tools, as well as vaccines.

Culturing Mycobacteria.

Building upon the foundational research of Robert Koch, who demonstrated the ability to grow Mycobacterium tuberculosis for the first time in 1882 using media made of coagulated bovine serum, microbiologists have continued to develop new and more efficient ways to grow mycobacteria. Presently, all known mycobacterial species can be grown in the laboratory using either axenic culture techniques or in vivo passage in laboratory animals. This chapter provides conventional protocols to grow mycobacteria for diagnostic purposes directly from clinical specimens, as well as in research laboratories for scientific purposes. Detailed protocols used for production of M. tuberculosis in large scale (under normoxic and hypoxic conditions) in bioreactors and for production of obligate intracellular pathogens such as Mycobacterium leprae and "Mycobacterium lepromatosis" using athymic nude mice and armadillos are provided.

Essential Roles of PPARs in Lipid Metabolism during Mycobacterial Infection.

The mycobacterial cell wall is composed of large amounts of lipids with varying moieties. Some mycobacteria species hijack host cells and promote lipid droplet accumulation to build the cellular environment essential for their intracellular survival. Thus, lipids are thought to be important for mycobacteria survival as well as for the invasion, parasitization, and proliferation within host cells. However, their physiological roles have not been fully elucidated. Recent studies have revealed that mycobacteria modulate the peroxisome proliferator-activated receptor (PPAR) signaling and utilize host-derived triacylglycerol (TAG) and cholesterol as both nutrient sources and evasion from the host immune system. In this review, we discuss recent findings that describe the activation of PPARs by mycobacterial infections and their role in determining the fate of bacilli by inducing lipid metabolism, anti-inflammatory function, and autophagy.

Autophagy as a Target for Drug Development Of Skin Infection Caused by Mycobacteria.

Pathogenic mycobacteria species may subvert the innate immune mechanisms and can modulate the activation of cells that cause disease in the skin. Cutaneous mycobacterial infection may present different clinical presentations and it is associated with stigma, deformity, and disability. The understanding of the immunopathogenic mechanisms related to mycobacterial infection in human skin is of pivotal importance to identify targets for new therapeutic strategies. The occurrence of reactional episodes and relapse in leprosy patients, the emergence of resistant mycobacteria strains, and the absence of effective drugs to treat mycobacterial cutaneous infection increased the interest in the development of therapies based on repurposed drugs against mycobacteria. The mechanism of action of many of these therapies evaluated is linked to the activation of autophagy. Autophagy is an evolutionary conserved lysosomal degradation pathway that has been associated with the control of the mycobacterial bacillary load. Here, we review the role of autophagy in the pathogenesis of cutaneous mycobacterial infection and discuss the perspectives of autophagy as a target for drug development and repurposing against cutaneous mycobacterial infection.

Antimicrobial Activity of Neutrophils Against Mycobacteria.

The mycobacterium genus contains a broad range of species, including the human pathogens M. tuberculosis and M. leprae. These bacteria are best known for their residence inside host cells. Neutrophils are frequently observed at sites of mycobacterial infection, but their role in clearance is not well understood. In this review, we discuss how neutrophils attempt to control mycobacterial infections, either through the ingestion of bacteria into intracellular phagosomes, or the release of neutrophil extracellular traps (NETs). Despite their powerful antimicrobial activity, including the production of reactive oxidants such as hypochlorous acid, neutrophils appear ineffective in killing pathogenic mycobacteria. We explore mycobacterial resistance mechanisms, and how thwarting neutrophil action exacerbates disease pathology. A better understanding of how mycobacteria protect themselves from neutrophils will aid the development of novel strategies that facilitate bacterial clearance and limit host tissue damage.

Mycobacterial Infections in the Hand and Wrist.

Mycobacterial hand infections are uncommon. These infections have an indolent course and are marked by variable and nonspecific presentations, often leading to diagnostic and treatment delays. The pathogens involved in mycobacterial hand infections include Mycobacterium tuberculosis complex, atypical mycobacteria, and M leprae. Initial treatment involves a combination of long-term antibiotics and surgical débridement to cure the infection. Reconstructive procedures aid in restoring hand function lost secondary to the disease.

Long-term ulcerations caused by Mycobacterium lepromatosis.

Patients with leprosy rarely present ulcerated lesions that can appear during reactional states like Lucio's phenomenon (LP), as in our case. LP is a rare complication of multibacillary leprosy due to massive bacilli invasion of endothelial cells causing a thrombotic syndrome. The initial macular lesion is purpuric followed by multiple infiltrated papules and nodules, some of them ulcerated, associated to loss of sensation on lower limbs. The importance of recognizing ulcers as a specific cutaneous manifestation of leprosy allows early diagnosis and treatment, and therefore avoiding the development of disabilities and persistence of illness. Infection by Mycobacterium lepromatosis is associated with LP and it should be especially sought in patients from endemic areas.

Caprine nodular thelitis due to Mycobacterium uberis: A series of 26 cases in 11 dairy goat farms in Western France.

Bovine Nodular Thelitis (BNT) is a granulomatous dermatitis of teat skin associated with acid-fast bacilli. A similar condition has been recorded in a dairy goat flock in France recently. The causative agent was shown to be related to the leprosy-causing bacilli Mycobacterium leprae and M. lepromatosis, then sequenced and named M. uberis. Following the initial report in goats, the aim of this study was to investigate new cases of Caprine Nodular Thelitis (CNT) in the same area to confirm the presence of M. uberis by molecular techniques and to get a better description of the clinical signs and of the affected flocks. Twenty-six animals (25 females and 1 male) from 11 flocks were included in the study. Lesions were located on the udder/teat skin (24/25), on the body skin (6/25) or on the scrotum skin (1/1). Udder skin lesions were circular, nodular and/or ulcerate covered with a crust and associated with supramammary lymph node enlargement. Body skin lesions were located at different parts of the body, showed large necrotizing ulcers with undetermined edges and were associated with regional lymph node enlargement. Histopathological results indicated granulomatous dermatitis and lymphadenitis of varying intensity with no acid-fast bacilli seen after Fite-Faraco staining. M. uberis DNA was amplified from 26 samples out of 47 (udder: 11/22; lymph node: 11/20; body: 4/5). The female goats were mostly older than 4 year of age and originated from breeding units characterized by large flock size and high proportion of goat in continuous lactation.

Polineuropatia desmielinizante como manifestação inicial isolada de hanseníase: relato de caso / Demyelinating polyneuropathy as an isolated initial manifestation of leprosy: case report

RESUMO: Modelo do Estudo: Relato de caso. Importância do problema: No mundo, mais de três milhões de pessoas estão vivendo com deficiência física devido à hanseníase. O Brasil é o segundo país com o maior número de casos novos registrados.A magnitude e o alto risco de incapacidade mantêm a doença como problema de saúde pública. O diagnóstico de hanseníase em geral é simples. Porém, quadros com ausência de lesões cutâneas características, somente com alterações neurais, representam um desafio para o diagnóstico diferencial com outras doenças neurológicas. Comentários: Relatamos o caso de um paciente encaminhado ao serviço de neurologia com história clínica e eletroneuromiografia compatíveis com polineuropatia desmielinizante, sem qualquer lesão cutânea ao exame de admissão. O raciocínio clínico inicial foi direcionado para o diagnóstico das polineuropatias desmielinizantes inflamatórias adquiridas como Polineuropatia Desmielinizante Inflamatória Crônica (CIDP) e suas variantes. No entanto, após anamnese e exame físico detalhados, chamou a atenção a ausência do componente atáxico e a presença predominante de alterações sensitivas de fibra fina, espessamento de nervo e importante fator epidemiológico para hanseníase, motivando a suspeita e a in-vestigação desta enfermidade por meio da biópsia de nervo que foi sugestiva de hanseníase. Após três meses, em novo exame do paciente para biopsiar áreas de anestesia para reforçar o diagnóstico, observou-se o surgimento de extensas lesões levemente hipocrômicas no tronco e membros inferiores, cuja biópsia definiu o diagnóstico de hanseníase. (AU)

ABSTRACT: Study: Case report. Importance: Worldwide over three million people are living with disabilities due to leprosy. Brazil is the second country with the highest number of new cases registered. The magnitude and high risk of disability make the disease a public health problem. The diagnosis of leprosy can be simple. However, in the absence of skin lesions and with many possibilities of neurological impairment, diagnosis can become a challenge. Comments: We report the case of a patient referred to the neurology service with a clinical history and electrophysiological tests compatible with demyelinating polyneuropathy, without any skin lesion at admission examination. The initial clinical research was directed to the diagnosis of acquired inflammatory demyelinating polyneuropathies such as Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)and its variants. However, after anamnesis and detailed physical examination, the absence of the ataxic component and the predominant presence of sensory alterations of fine fiber, nerve thickening and important epidemiological factor for leprosy,led to the suspicion and investigation of this disease by nerve biopsy that was suggestive of leprosy. After three months, in a new patient examination "to perform a biopsy in areas of anesthesia" to reinforce the diagnosis, there was the appearance of extensive slightly hypochromic lesions in the trunk and lower limbs, whose biopsy defined the diagnosis of leprosy.(AU)

Flavonoids as Novel Efflux Pump Inhibitors and Antimicrobials Against Both Environmental and Pathogenic Intracellular Mycobacterial Species.

Therapeutic treatment options for opportunistic non-tuberculous mycobacterial (NTM) infection and/or serious mycobacterial infections such as tuberculosis (TB) and leprosy are limited due to the spread of antimicrobial resistance mechanism. Plant-derived natural compounds as prospective efflux pump inhibitors may present a promising adjunct to conventional chemotherapy by enhancing mycobacterial susceptibility to antibiotics. This study served to evaluate the antimicrobial and resistance-modifying profile of a range of plant-derived flavonoids against the mycobacterial model strains: M. smegmatis, M. aurum, and M. bovis BCG. The minimum inhibitory concentrations (MICs) of the compounds against the mycobacterial strains were determined using both agar dilution and broth dilution assays, while their efflux inhibitory activity was investigated via an ethidium bromide-based fluorometric assay. All compounds were screened for their synergistic effects with ethidium bromide (EtBr) and rifampicin (RIF) against M. smegmatis. Skullcapflavone II (5,2'-dihydroxy-6,7,8,6'-tetramethoxyflavone, 1) exerted potent antimicrobial activity against M. aurum and M. bovis BCG and considerably increased the susceptibility of M. smegmatis to EtBr and RIF. Nobiletin (5,6,7,8,3',4'-hexamethoxyflavone, 2) was determined to be the most potent efflux-inhibitor in M. aurum and M. smegmatis. However, a connection between strong modulatory and putative efflux activity of the compounds could not be observed. Nevertheless, the results highlight two polymethoxyflavones, skullcapflavone II and nobiletin, with potent antimycobacterial and antibiotic resistance modulating activities as valuable adjuvants in anti-mycobacterial therapies.

The selective autophagy receptors Optineurin and p62 are both required for zebrafish host resistance to mycobacterial infection.

Mycobacterial pathogens are the causative agents of chronic infectious diseases like tuberculosis and leprosy. Autophagy has recently emerged as an innate mechanism for defense against these intracellular pathogens. In vitro studies have shown that mycobacteria escaping from phagosomes into the cytosol are ubiquitinated and targeted by selective autophagy receptors. However, there is currently no in vivo evidence for the role of selective autophagy receptors in defense against mycobacteria, and the importance of autophagy in control of mycobacterial diseases remains controversial. Here we have used Mycobacterium marinum (Mm), which causes a tuberculosis-like disease in zebrafish, to investigate the function of two selective autophagy receptors, Optineurin (Optn) and SQSTM1 (p62), in host defense against a mycobacterial pathogen. To visualize the autophagy response to Mm in vivo, optn and p62 zebrafish mutant lines were generated in the background of a GFP-Lc3 autophagy reporter line. We found that loss-of-function mutation of optn or p62 reduces autophagic targeting of Mm, and increases susceptibility of the zebrafish host to Mm infection. Transient knockdown studies confirmed the requirement of both selective autophagy receptors for host resistance against Mm infection. For gain-of-function analysis, we overexpressed optn or p62 by mRNA injection and found this to increase the levels of GFP-Lc3 puncta in association with Mm and to reduce the Mm infection burden. Taken together, our results demonstrate that both Optn and p62 are required for autophagic host defense against mycobacterial infection and support that protection against tuberculosis disease may be achieved by therapeutic strategies that enhance selective autophagy.