The UPOBioinfo group, led by the professor Antonio J. Pérez-Pulido in the University Pablo de Olavide in Seville (Spain), together with the group of the Institute of Biomedicine of Seville, and the University Hospital Virgen del Rocío, and professors from the Data Science & Big Data Research Lab, with Federico Divina and Miguel García, started the analysis of around 2,500 genomes of A. baumannii in 2018. The project is part of the PhD thesis of Eugenio L. Mangas and they have now published the initial results in the journal of the Microbiology Society, Microbial Genomics. This is the first time that the complete set of genes of this bacterium has been proposed and it distinguishes between two different types of strains.
“On one hand there are strains that have a lower number of genes, which could be due to the immunity systems that they present. Specifically, these strains present systems called CRISPR-Cas, which are recently known and they would avoid the entrance of new genes into the bacterium. The other group of strains has barely immunity systems and it could allow to them to have a higher number of genes, specially from the extra-chromosomal structures called plasmids”, explains Dr. Pérez-Pulido. These strains could present genes involved both in virulence and antibiotic resistance much more easily, and the control of these bacterial immunity systems could be a powerful weapon against the infections by these kind of infectious organisms, says the researcher.
To analyze these thousands of genomes, tells Pérez-Pulido, was necessary to use the supercomputer in the Center of Scientific Calculation from UPO (C3UPO), where its system administrator performed differents in silico experiments, including phylogenies of the species.
The World Health Organization recently classified carbapenem-resistant A. baumannii as priority 1 for developing new antibiotics in the fight against the species, together with Pseudomonas aeruginosa, and the Enterobacteriaceae family. A. baumannii is a bacterium causing opportunistic infections in hospital environments. In fact, the species is responsible for more than 10% of intra-hospital infections, and causes different diseases such as pneumonia, bacteremia, infections of skin and soft tissues, endocarditis and urinary tract infections or secondary meningitis, among others. It mainly affects immunodeficient or hospitalized patients in the intensive care units, and produces one million of infections all over the world, with around 15,000 deaths.
The bacterium is dispersed by air in short distances, or by scaling of skin from colonized patients. But the predominant transmission mode is through hospital surfaces and devices, or by the hands of health workers. The high morbidity and mortality that A. baumannii presents is mainly due to it is a multidrug-resistant bacterium with strains which resist to the majority of usually used antibiotics. Finally, it is remarkable that infections by A. baumannii have increased from the time of the Iraq War in 2003, and it is thought that some strains from the bacterium come from wounds suffered by soldiers from this conflict, and so the bacterium is sometimes referred as iraqibacteria.
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