Findings in the Molecular and Proteomic Diagnosis of Nocardia brasiliensis

Nowadays, cases of so-called neglected diseases (related to poverty) are increasing. One of them is mycetoma and its variants: Actinomycetoma (caused by bacteria) and eumycetoma (caused by fungi). In the case of actinomycetoma, this disease is often not reported and, as it does not cause pain, people who suffer from it usually go to the doctor when the lesions cause them discomfort when moving or work or social problems. While the diagnosis is usually “easy” since it is mainly based on cultures and stains, many times this is omitted, giving rise to subclinical diagnoses. In this work we strive to make an accurate diagnosis for a patient who suffered from actinomycetoma caused by Nocardia brasilliensis and who was treated with miconazole (an antifungal) for 10 years. After collecting the sample, the corresponding cultures and stains were performed to identify the causal agent, which is Nocardia brasilliensis. Although when talking about the causative agents of actinomycetoma, this aforementioned bacteria is the most studied and reported, we undertook the task of confirming in a more precise way the agent with which we were dealing, for which a procedure was standardized for the identification of the 16S rRNA gene of this bacteria by means of genomic PCR and the realization of the genetic fingerprint mediated by restriction enzymes of Restriction Fragment Length Polymorphism (polymorphisms of the length of restriction fragments) for the 18 strains cultivated in Saburoud Dextrose agar plates. Despite the fact that this gene is present in a huge quantity of bacteria and also that this genus of bacteria has the capacity to mutate certain genes with different organisms that share its environment, such as Aspergillus sp, Fusarium sp, Actinomadura sp, Madrurela sp. This gene does not have homologous regions between the different genera and species that have it, since it has been used for more than 20 years in the identification of this bacteria by PCR with restriction enzymes. In addition, the mutations that could be generated do not occur in the region of this gene since thousands of years have to pass so that they can be expressed and therefore be noticed. This is how, through the extraction, purification, and quantification of the genetic material for its subsequent sequencing with the help of virtual tools such as the BLAST program (Basic Local Alignment Search Tool) that belongs to NCBI, we were able to demonstrate the presence of this 16S rRNA gene in order to have an exact diagnosis of Nocardia brasiliensis.