Is there a Function for a Sex Pheromone Precursor?:A Predicted Link between Bacterial Redox Metabolism and Propagation of Antibiotic Resistance

Functional coupling and comparative genomics analysis have been applied to study functional associations of orthologs of enterococcal cAD1 sex pheromone (P13268) known to be responsible for biofilm formation, conjugative plasmid transfer and spreading of bacterial antibiotics resistance. cAD1 peptide pheromone is released from the membrane lipoprotein with the peptide precursor encoded by a gene cad (tr|C2JQE7). Our analysis of genomic neighbourhood of cad and motifs of the encoded polypeptide and its orthologs suggests a close functional association between cAD1 and ApbE protein (Q82Z24), a FMN insertion and trafficking facilitator. The cad and apbE orthologs were coupled in the genomes and ApbE-specific motifs for FMN covalent attachment were identified in cad-encoded protein sequence and its orthologs. These findings suggest a potential role of FMN-based reductase function of the cAD1 lipoprotein precursor in its processing and release of the active sex pheromone peptide. They may lead to a new approach in prevention of antibiotic resistance spread via targeting sex pheromone processing chaperones or by suppression of the FMN availability and covalent binding. This methods can be also applied to a controlled evolution of bacterial pathogenicity in microbial fuel cells, as the findings suggest the crosstalk between bacterial pathogenicity and bacterial electro-activity

Antimicrobial susceptibility and molecular characterization of resistance mechanisms of Enterococcus spp. from the intestinal microbiota of food producing animals

O trato intestinal dos mamíferos constitui um reservatório natural de Enterococcus, bactérias oportunistas, ubiquitárias, frequentemente associadas a infeções nosocomiais multirresistentes em humanos, sendo Enterococcus faecium e Enterococcus faecalis as espécies mais importantes. Neste estudo foram identificadas as espécies de Enterococcus predominantes no conteúdo cecal de bovinos e suínos através de técnicas moleculares, tendo sido avaliados os perfis de suscetibilidade antimicrobiana das estirpes de E. faecium e E. faecalis pelos métodos de agar difusão e microdiluição, e identificados determinantes de resistência por PCR e Whole Genome Sequencing. Os suínos constituem um reservatório de estirpes multirresistentes de E. faecium e E. faecalis. Enteroccocus spp. resistentes a antibióticos de importância crítica, designadamente daptomicina e linezolid, foram identificados em intestino de bovinos e suínos, tendo sido detectados os determinantes de resistência ao linezolid (optrA e poxtA). Estes resultados enfatizam a importância de monitorizar a resistência antimicrobiana em bactérias de origem animal; ABSTRACT: The intestinal tract of mammals is a natural reservoir of Enterococcus, opportunistic and ubiquitous bacteria, frequently associated with multidrug resistant nosocomial infections in humans, Enterococcus faecium and Enterococcus faecalis being the most important species. In the present study, the prevalent species of Enterococcus in the cecum of cattle and pigs were identified through molecular techniques, the antimicrobial susceptibility profiles of E. faecium and E. faecalis strains were assessed by agar diffusion and microdilution methods, and resistant determinants were identified through PCR and Whole Genome Sequencing. Pigs are a reservoir of multidrug resistant E. faecium and E. faecalis strains. Enterococcus spp. resistant to critically important antibiotics, namely daptomycin and linezolid, were found colonizing bovine and swine gut, and the corresponding linezolid resistance determinants were identified (optrA and poxtA). These results highlight the importance of monitoring antimicrobial resistance mechanisms in bacteria from animals