Human Intestinal Microbiome—A Reservoir of Aminoglycoside-N-Acetyltransferases—Drug Resistance Genes

The human gut microbiome is a complex ecosystem that plays a key role in maintaining overall homeostasis and is a dynamic reservoir of antibiotic resistance genes that can be transferred between bacteria in mixed populations. One of the main enzymes that carry out the acetylation of a wide range of substrates is aminoglycoside- N -acetyltransferase (AAC). Previously, the bifunctional enzyme AAC(6')-Ie/APH(2'')-Ia was identified and characterized in Enterococcus and Staphylococcus , which is a clinically important enzyme. Within the framework of this study, genes encoding AAC(3) were identified in the sequenced genomes of strains belonging to Bacteroides and Lactobacillus . In the genomes of strains belonging to most species of Bacteroides , Enterococcus , and Lactobacillus , genes encoding Eis have been identified. The sequences of all identified AAC(3) and Eis do not resemble the sequences of known enzymes. AAC(3) and Eis in these bacteria may have different functions in the human body, including participation in the acetylation of peptides, proteins, and other substrates.