Mycobacterium marinum is an opportunistic pathogen inducing infection in fresh and marine water fish. This pathogen causes necrotizing granuloma like tuberculosis, morbidity and mortality in fish. The cell wall-associated lipid phthiocerol dimycocerosates, phenolic glycolipids and ESAT-6 secretion system 1 (ESX-1) are the conserved virulence determinant of the organism. Human infections with Mycobacterium marinum hypothetically are classified into four clinical categories (type I-type IV) and have been associated with the exposure of damaged skin to polluted water from fish pools or contacting objects contaminated with infected fish. Fish mycobacteriosis is clinically manifested and characterized in man by purple painless nodules, liable to develop into superficial crusting ulceration with scar formation. Early laboratory diagnosis of M. marinum including histopathology, culture and PCR is essential and critical as the clinical response to antibiotics requires months to be attained. The pathogenicity and virulence determinants of M. marinum need to be thoroughly and comprehensively investigated and understood. In spite of accumulating information on this pathogen, the different relevant data should be compared, connected and globally compiled. This article is reviewing the epidemiology, virulence factors, diagnosis and disease management in fish while casting light on the potential associated public health hazards.
Mycobacterium bovis
is responsible for bovine tuberculosis in both animals and humans. Despite being one of the most important global zoonotic disease, data related to the ecology and pathogenicity of bovine tuberculosis is scarce, especially in developing countries. In this report, we examined the dynamics of
M. bovis
transmission among dairy cattle in the Nile Delta of Egypt. Animals belonging to 27 herds from 7 governorates were tested by the Single Intradermal Comparative Skin Tuberculin (SICST), as a preliminary screen for the presence of bovine tuberculosis. Positive SICST reactors were identified in 3% of the animals spread among 40% of the examined herds. Post-mortem examination of slaughtered reactors confirmed the presence of both pulmonary and/or digestive forms of tuberculosis in > 50% of the examined animals. Targeted and whole-genome analysis of
M. bovis
isolates indicated the emergences of a predominant spoligotype (SB0268) between 2013–2015, suggesting a recent clonal spread of this isolate within the Nile Delta. Surprisingly, 2 isolates belonged to
M. bovis
BCG group, which are not allowed for animal vaccination in Egypt, while the rest of isolates belonged to the virulent
M. bovis
clonal complex European 2 present in Latin America and several European countries. Analysis of strain virulence in the murine model of tuberculosis indicated the emergence of a more virulent strain (MBE4) with a specific genotype. More analysis is needed to understand the molecular basis for successful spread of virulent isolates of bovine tuberculosis among animals and to establish genotype/phenotype association.
Tuberculosis (TB) is one of the most important infectious zoonotic diseases of vertebrates worldwide. TB in animals is primarily known from cases in cattle and other bovids for which the disease is generally referred to as bovine TB. The major causative agent of bovine TB is Mycobacterium bovis (M. bovis), a member of the Mycobacterium tuberculosis complex. Animal TB is a disease of high economic relevance within the context of livestock farming as it directly affects animal productivity and also influences international trade of animal products. In this study, we aimed at mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR) analysis of cases of TB infection in local cattle in Egypt. Therefore, various samples (milk and blood samples) were collected from cattle farms (in Damietta Province) that were positive for tuberculin test. Mycobacterial isolation was tested on milk samples, but it showed negative result. DNA was extracted from blood samples. Five mycobacterial genes (IS6110, katG, gyrA, oxyR, pncA) were used for further confirmation of field TB infection. All blood samples were positive for Mycobacterial-specific genes. Twelve MIRU-VNTR loci were used to test their discriminatory power in the genetic analysis of TB, but such MIRU-VNTR loci typing failed to show any discriminatory power for the genetic analysis of bovine TB cases.
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