Search Results (49)

In this report, we describe systemic granulomatous mycobacteriosis in an orbiculate batfish from an aquarium in South Korea. Gross examination of the deceased fish showed multifocal nodular lesions in multiple internal organs including the gills, spleen, and kidney. Histopathological analysis demonstrated severe chronic systemic granulomatous inflammation, and Ziehl–Neelsen staining highlighted abundant intralesional acid-fast bacilli. Molecular analysis based on partial sequencing of the 16S ribosomal RNA (rRNA) and heat shock protein 65 (hsp65) genes showed that the detected organism was most closely related to Mycobacterium marinum. Because the molecular analysis was performed using partial sequences obtained from formalin-fixed, paraffin-embedded tissues, definitive species-level identification was not possible. This case represents systemic granulomatous mycobacteriosis associated with a Mycobacterium marinum-like organism in orbiculate batfish in an aquarium in South Korea and emphasizes the need for continuous disease surveillance and improved diagnostic awareness of non-tuberculous mycobacterial infections in ornamental and public aquarium fish. Full article

Mycobacteria isolated only once in repeated sputum cultures are deemed colonizers that are not normally present in the lungs despite their ubiquitous presence in the environment. We have developed a sensitive and specific PCR assay to detect slow-growing mycobacteria in culture negative sputum and have found them in 30% of the samples obtained from individuals with clinical suspicion of tuberculosis or mycobacteriosis (n = 50) and in 45% of the samples from individuals with no suspicion (n = 49). As a negative control we have analyzed infections from an extra-pulmonary location, the urinary tract (n = 21), in which mycobacterioses are rare, and did not detect them. The load of bacteria in the lungs is kept low by the defense mechanisms of the host, and mycobacteria are not normally detected in sputum cultures. Their incidental isolation would not be a consequence of a new exposure to the microorganism but a sign of susceptibility to mycobacteriosis. Full article

Background: Drug susceptibility testing in Mycobacterium species typically requires prolonged incubation periods during which the chemical integrity of antibiotics may not be maintained, potentially compromising the reliability and accuracy of minimum inhibitory concentration (MIC) determinations. Objectives: This study evaluated the in vitro stability of several antibiotics, including recently introduced agents (bedaquiline [BDQ], pretomanid, delamanid and clofazimine) used for treating multidrug-resistant mycobacteriosis (linezolid and moxifloxacin), and those commonly included in combination regimens (rifampicin, isoniazid, ethambutol and clarithromycin). Methods: Antibiotics were pre-incubated at 37 °C before MIC determination and those exhibiting two or more dilutions in MIC were further tested in combination with ascorbic acid (AA) and pyruvate (P). Results: All antibiotics demonstrated stability except BDQ, which showed significant MIC variation after pre-incubation, which was prevented when BDQ was combined with AA and P. Conclusions: These findings suggest that the combined use of AA and P may serve as an effective stabilizing strategy for BDQ during MIC determination. Full article

Background: The global incidence of infections caused by nontuberculous mycobacteria (NTM), environmental pathogens commonly found in soil and water, is increasing. Among the various NTM species, Mycobacterium avium is most frequently implicated. Clinical manifestations are diverse and include chronic pulmonary disease, disseminated infection, and cervical lymphadenopathy, particularly in children. This study aimed to evaluate the diagnosis and treatment of NTM-associated cervical lymphadenopathy at a tertiary referral center. Methods: All patients treated for NTM-associated cervical lymphadenopathy at the Department of Otorhinolaryngology, Medical University of Innsbruck, between 2010 and 2024 were retrospectively analyzed. Demographic data, imaging findings, microbiological results, therapy, and follow-up were evaluated. Results: A total of 22 patients with a median age of 1 (IQR 2) year were identified, most of whom originated from rural areas (91%). Diagnosis was based on characteristic clinical and imaging findings. Cervical ultrasonography was performed in all patients, and additional magnetic resonance imaging was performed in 55%. Microbiological confirmation was achieved in 64% of cases using liquid or solid cultures, while no pathogen was detected in 36%. Treatment consisted of combined antibiotic therapy with clarithromycin and rifampicin for 3–6 months, with additional surgical intervention in selected cases. Follow-up demonstrated clear regression of lymphadenopathy in the majority of patients within six months. Conclusions: NTM infection should be considered in the differential diagnosis of cervical lymphadenopathy. Pathogen detection remains challenging, and antimicrobial therapy alone may be sufficient in selected cases. Full article

Nontuberculous mycobacteria are opportunistic pathogens increasingly associated with human disease. Within this group, the Mycobacterium avium complex (MAC), which includes M. avium, M. intracellulare and M. intracellulare subsp. chimaera, is the most frequent cause of infection. The increase in MAC cases worldwide has made it crucial to understand their population structure, clinical relevance and resistance mechanisms. Recent advances in whole-genome sequencing (WGS) and molecular approaches have improved the knowledge of taxonomy, population structure and genetic diversity, while also enabling the investigation of transmission and epidemiology. Clinically, MAC most often causes chronic pulmonary disease, but extrapulmonary forms, including disseminated disease, also occur. Presentation can vary by infecting species, while host factors such as pre-existing lung disease or immunosuppression further increase the risk. Treatment outcomes remain less favourable than desired, in part due to antimicrobial resistance involving de novo-acquired mutations. Pathogenesis is also influenced by interactions between MAC and host cells, including mechanisms of immune evasion and inflammatory modulation. In addition, emerging evidence suggests that gut–lung axis dysbiosis may influence susceptibility to MAC infection. This review outlines current knowledge on the population structure, clinical significance, resistance and host–pathogen interactions of MAC. Full article

Fish mycobacteriosis, a chronic progressive disease caused by nontuberculous mycobacteria (NTM), affects marine, brackish, and freshwater fish. Mycobacterium marinum (M. marinum), the most important of the NTM, infects fresh and marine water fish causing necrotizing granulomas and associated morbidity and mortality. M. marinum causes disease in zebrafish in a dose-dependent fashion. The M. marinum-induced disease in the zebrafish is associated with the development of necrotizing granulomas with abundant bacteria in the necrotic areas. Acute infection with high infectious doses of M. marinum infection in zebrafish was characterized by uncontrolled replication of the pathogen and death of all fish within 16 days, while chronic infections were marked by the formation of granulomas in different organs and longer survival in the range of 4–8 weeks. This review therefore synthesizes recent advances in our understanding of M. marinum’s infection of zebrafish, molecular pathogenesis, virulence mechanisms, and immune evasion strategies in zebrafish, while also highlighting the host immune effector responses and the virulence mechanisms of M. marinum. Full article

A female domestic shorthair cat aged 2 years was referred with a 1-month history of subcutaneous nodules and multiple sites of draining tracts at the ventral abdomen. Initially, the cat was diagnosed with a fungal infection and treated with oral itraconazole, without improvement. Comprehensive diagnostics, including cytology, which indicated pyogranulomatous inflammation, fungal culture that was negative, and bacterial culture, confirmed the presence of Mycobacterium abscessus. This infection was treated with a combination of oral azithromycin and topical amikacin based on susceptibility testing; later, doxycycline and an immunostimulant supplemented were combined at day 36 of treatment due to mild improvement of the lesions. The cat showed gradual improvement, achieving complete resolution of the lesions after 14 weeks, with no relapse noted 24 weeks post-treatment. This case report demonstrates the diagnostic challenges and the necessity for tailored, multi-drug therapeutic approaches in managing mycobacterial infections in cats. The findings may guide future treatments and raise awareness of mycobacterial diseases in cats. Full article

Background/Objectives: The nuclear factor (NF)-kB essential modulator (NEMO) has a crucial role in the NFκB pathway. Hypomorphic IKBKG pathogenic variants cause ectodermal dysplasia with immunodeficiency (EDA-ID) in affected males. However, heterozygous amorphic IKBKG variants could be responsible for Incontinentia Pigmenti (IP) in female carriers. Typically, IP patients do not exhibit immunodeficiency, although hypomorphic variants might lead to immunodeficiency in female IP patients. Here, we report the case of an IKBKG female carrier, with no IP but an unexpected picture of immunodeficiency. She had a positive family history for the same genetic condition. Methods: We performed immunological, molecular, and functional analysis to evaluate NEMO contribution. Results: The patient was healthy until the age of 25 when severe asthma and Hashimoto thyroiditis occurred. She had HLAB27-positive ankylosing spondylitis, non-tubercular mycobacteriosis, and pulmonary aspergillosis infections. We found CD19+ B cell lymphopenia and T cell subset alterations. Sanger sequencing revealed a heterozygous IKBKG variant at position +1 of the 5′ UTR of the gene which disrupted the normal pre-mRNA splicing. We observed a decreased NEMO protein expression, a reduced level of mRNA, and a defective NF-κB pathway. Conclusions: These findings suggest a possible correlation between the partial loss of NEMO function and the immunodeficiency observed in this patient. This case could expand our understanding of NEMO deficiency in female carriers. Full article

Background: Syphilis has recently reemerged as a significant public health concern, with rising incidence rates globally. Malignant syphilis is a rare and severe variant of secondary syphilis, often associated with immunocompromised states, particularly HIV infection. Methods: Here, we reported a rare case of malignant syphilis in a young man with well-controlled HIV. Case: A 35-year-old man with well-controlled HIV presented with disseminated ulcerated nodules and plaques, accompanied by fever, asthenia, and mild itching. Histopathology of the scapular ulcer revealed a granulomatous infiltrate. Cutaneous leishmaniasis, atypical mycobacteriosis, and T-cell lymphomas were excluded. Serological testing and polymerase chain reaction confirmed a diagnosis of malignant syphilis. Full article

Diagnosing non-tuberculous mycobacterial pulmonary disease (NTM-PD) in patients unable to produce sputum spontaneously requires invasive procedures to obtain valid respiratory specimens. In this retrospective study, we evaluated the results of microbiological tests performed on respiratory samples of 132 patients affected by NTM-PD. In the diagnostic workout, 98 patients performed both induced sputum (IS) and bronchoalveolar lavage (BAL) and were enrolled in our study. A total of 93 out of 98 BAL samples (95%) were culture-positive for mycobacteria, whereas only 67/153 (44%) induced sputum cultures were positive for NTM (p < 0.001). Molecular identification of NTM with real-time polymerase chain reaction (PCR) was positive in 48/64 BAL (75%) and in 47/139 (34%) IS samples (p < 0.001). Patients affected by nodular-bronchiectatic form were 65/98 (66%): BAL culture was positive in 95% of cases (62/65 BAL), while only 30/99 IS cultures were positive (30%; p < 0.001). PCR was positive in 76% of BAL samples examined (26/34) and in 26% of the IS samples (24 out of 91) (p < 0.001). Among 33 patients with a fibro-cavitary radiological pattern, 65% of IS (35/54) were culture-positive for NTM, whereas 94% of cases (31/33) had a positive culture for NTM from BAL (p = 0.002). PCR was positive in 73% of BAL samples tested (22/30) and 48% of IS samples tested (23/48) (p = 0.031). Our results confirm BAL mycobacterial culture as the gold standard for the diagnosis of pulmonary mycobacteriosis. FBS with BAL should be performed in every patient with a strong suspicion of NTM-PD, if other respiratory samples are repeatedly negative. Sputum induction is a useful technique to obtain valid respiratory samples when patients are unable to produce spontaneous sputum, especially in the outpatient setting. However, during the diagnostic workup of NTM-PD, we should not forget that PCR and mycobacterial culture of induced sputum have a lower yield than when performed on BAL, especially in the nodular-bronchiectatic form of the disease. Full article

Fast-growing mycobacteria cause difficult-to-treat infections due to their high intrinsic resistance to antibiotics as well as disinfectant agents. Mycobacterium abscessus complex (MAC) is the main cause of nontuberculous mycobacteria diseases. In this work, we evaluated the activity of the novel synthetic antimicrobial peptide, Agelaia-12, against Mycobacterium abscessus and M. massiliense. Agelaia-12 showed a minimum inhibitory concentration (MIC) of 25 μM detected against M. abscessus and M. massiliense with no cytotoxicity. The scanning electronic microscopy analysis of mycobacterial treated with Agelaia-12 demonstrated the presence of filamentous structures and aggregation of the cells. Congo red binding assay of M. abscessus exhibited altered dye accumulation after treatment with Agelaia-12. Treatment of M. abscessus- or M. massiliense-infected murine macrophages with Agelaia-12 decreased the mycobacterial load by 92% for the tested strains. Additionally, IFN-y KO mice infected with M. abscessus or M. massiliense and treated with Agelaia-12 showed a 98% reduction in lung bacterial load. Thus, the synthetic peptide Agelaia-12 may be a promising biomolecule for the treatment of mycobacteriosis, and its structural properties may serve as a foundational model for the design and development of novel pharmaceutical agents aimed at combating this disease. Full article

Mycolicibacterium hassiacum (homotypic synonym: Mycobacterium hassiacum) represents an ungrouped thermotolerant rapidly growing mycobacteria (RGM) species occasionally associated with infections and disease in humans. In this report, we describe a case of pyogranulomatous dermatitis and panniculitis due to M. hassiacum in an immunocompetent adult cat. To the best of our knowledge, this represents the first report of M. hassiacum infection in animals. We also report the results of the in-depth genome characterization of the isolate using a combined short- and long-read whole-genome sequencing (WGS) approach. We observed the lack of acquired-resistance genes and no evidence of mutations in housekeeping genes associated with resistance to rifampicin and isoniazid. We detected some virulence factors in our isolate, such as some associated with the interaction of mycobacteria with host cells, and the presence of multiple copies of heavy metal resistance genes (arsB, arsR, and arsL/cadL). In conclusion, M. hassiacum should be included among the RGM species associated with feline subcutaneous atypical mycobacteriosis (SAM). A reliable and fast RGM laboratory identification and characterization is important not only for an accurate etiological diagnosis but also for a correct approach to SAM treatment options. Full article

Mycobacterium avium subsp. avium is pathogenic mainly to birds, although cases of mycobacteriosis caused by these bacteria have also been reported in other animals and humans. Not much is known about the effects of this pathogen on otters. The aim of this study was to report for the first time the isolation of M. avium subsp. avium in wild otter and to describe its multidrug resistance profile. A female otter injured in a car accident was found dead and subjected to postmortem examination. Apart from the trauma changes, no other macroscopic pathological changes were detected. Bacteriologic examination revealed the presence of acid-fast bacilli in the lymph nodes, which were confirmed by molecular methods as M. avium subsp. avium. Antimicrobial susceptibility testing revealed susceptibility to clarithromycin and amikacin, but resistance to linezolid, moxifloxacin, streptomycin, isoniazid, trimethoprim/sulfamethoxazole, ciprofloxacin, doxycycline, and ethionamide. This is unusual for wild species, which generally should not come into contact with antimicrobials, and may suggest that multidrug-resistant MAC strains are circulating between wild and domestic animals. These results emphasise the need for additional epidemiological studies on non-tuberculous mycobacteria in wildlife and their implications for one health. Full article

Ferrets are highly susceptible to a wide range of mycobacteria, mainly M. bovis, M. avium, and M. triplex. Therefore, ferrets pose a risk of transmission of mycobacteriosis, especially zoonotically relevant tuberculosis. The aim of this study was to describe the findings of M. xenopi mycobacteriosis in a pet ferret and emphasize its zoonotic potential. A pet ferret had a history of weight loss, apathy, hyporexia, and hair loss. Abdominal ultrasound revealed splenomegaly with two solid masses and cystic lesions of the liver. Fine-needle aspiration cytology revealed numerous acid-fast bacilli in epithelioid cells, thus leading to the suspicion of mycobacterial infection. Because of its poor general condition, the ferret was euthanized. Necropsy examination revealed generalized granulomatous lymphadenitis, pneumonia, myocarditis, splenitis, and hepatitis. Histologically, in all organs, there were multifocal to coalescing areas of inflammatory infiltration composed of epithelioid macrophages, a low number of lymphocytes, and plasma cells, without necrosis nor multinucleated giant cells. Ziehl–Neelsen staining detected the presence of numerous (multibacillary) acid-fast bacteria, which were PCR-typed as M. xenopi. This is the first study showing the antimicrobial susceptibility testing of M. xenopi in veterinary medicine, describing the resistance to doxycycline. Overall, our results could facilitate further diagnosis and provide guidelines for the treatment protocols for such infections. Full article

During transition into a dormant state, Mycolicibacterium (Mycobacterium) smegmatis cells are able to accumulate free porphyrins that makes them sensitive to photodynamic inactivation (PDI). The formation of dormant cells in a liquid medium with an increased concentration of magnesium (up to 25 mM) and zinc (up to 62 µM) resulted in an increase in the total amount of endogenous porphyrins in dormant M. smegmatis cells and their photosensitivity, especially for bacteria phagocytosed by macrophages. To gain insight into possible targets for PDI in bacterial dormant mycobacterial cells, a proteomic profiling with SDS gel electrophoresis and mass spectrometry analysis were conducted. Illumination of dormant forms of M. smegmatis resulted in the disappearance of proteins in the separating SDS gel. Dormant cells obtained under an elevated concentration of metal ions were more sensitive to PDI. Differential analysis of proteins with their identification with MALDI-TOF revealed that 45.2% and 63.9% of individual proteins disappeared from the separating gel after illumination for 5 and 15 min, respectively. Light-sensitive proteins include enzymes belonging to the glycolytic pathway, TCA cycle, pentose phosphate pathway, oxidative phosphorylation and energy production. Several proteins involved in protecting against oxygen stress and protein aggregation were found to be sensitive to light. This makes dormant cells highly vulnerable to harmful factors during a long stay in a non-replicative state. PDI caused inhibition of the respiratory chain activity and destroyed enzymes involved in the synthesis of proteins and nucleic acids, the processes which are necessary for dormant cell reactivation and their transition to multiplying bacteria. Because of such multiple targeting, PDI action via endogenous porphyrins could be considered as an effective approach for killing dormant bacteria and a perspective to inactivate dormant mycobacteria and combat the latent form of mycobacteriosis, first of all, with surface localization. Full article