Genetic Basis of Antimicrobial Resistant Gram-Negative Bacteria Isolated From Bloodstream in Brazil

Abstract

Multidrug-resistant microorganisms are a well-known global problem, and gram-negative bacilli are top-ranking. When these pathogens are associated with bloodstream infections (BSI), outcomes become even worse. Here we applied whole-genome sequencing to access information about clonal distribution, resistance mechanism diversity and other molecular aspects of gram-negative bacilli (GNB) isolated from bloodstream infections in Brazil. It was possible to highlight international high-risk clones circulating in the Brazilian territory, such as CC258 for <i>Klebsiella pneumoniae</i>, ST79 for <i>Acinetobacter baumannii</i> and ST233 for <i>Pseudomonas aeruginosa</i>. Important associations can be made such as a negative correlation between CRISPR-Cas and <i>K. pneumoniae</i> CC258, while the genes <i>bla</i> _TEM, <i>bla</i> _KPC and <i>bla</i> _CTX-M are highly associated with this clone. Specific relationships between <i>A. baumannii</i> clones and <i>bla</i> _OXA-51 variants were also observed. All <i>P. aeruginosa</i> ST233 isolates showed the genes <i>bla</i> _VIM and <i>bla</i> _OXA486. In addition, some trends could be identified, where a new <i>P. aeruginosa</i> MDR clone (ST3079), a novel <i>A. baumannii</i> clonal profile circulating in Brazil (ST848), and important resistance associations in the form of <i>bla</i> _VIM-2 and <i>bla</i> _IMP-56 being found together in one ST233 strain, stand out. Such findings may help to develop approaches to deal with BSI and even other nosocomial infections caused by these important GNB.