Evaluation of Antimicrobial resistance determined in clinical isolates of Enterococcus spp. obtained from hospital patients in Latvia

Enterococci are typically found in the healthy human gastrointestinal tract but can cause severe infections in immunocompromised patients. These infections can be treated with antibiotics. This study addresses the rising concern of antimicrobial resistance (AMR) in Enterococci, focusing on the prevalence of vancomycin-resistant enterococcus (VRE) strains. It emphasizes the need to evaluate the diversity of AMR genes in Enterococcus species, understand the basis of resistance mechanisms and investigate the outbreaks in hospital settings to reduce the spread of VRE.The study involved 140 Enterococci isolates collected between 2021-2022 from two multidisci-plinary hospitals in Latvia. Microbiological assays and the whole genome sequencing method was used. AMR gene prevalence and resistance profiles were determined by using online data-bases. Genetic relationship and outbreak evaluation was made using core genome multi-locus sequence typing (cgMLST).Five Enterococcal species were identified, with Enterococcus faecalis and Enterococcus faecium being predominant. Genes and mutations were responsible for resistance against 10 antimicrobial classes, with 25.0% samples showing resistance to vancomycin, predominantly of the vanB type. Genetic diversity among E. faecalis and E. faecium isolates was observed and seven potential outbreak clusters were identified, three of them containing sequence types ST6, ST78 and ST80. Notably, a case of linezolid resistance due to a mutation was documented.The study highlights the concerning prevalence of multidrug-resistant Enterococci in Latvian hospitals, showcasing the widespread occurrence of vancomycin-resistant strains. The observed mutations and genes leading to resistance against various antibiotics highlight the urgency of implementing efficient infection control - the need for continuous VRE surveillance in Latvia to define the scope and pattern of the problem, influencing clinical decision-making and planning further preventative measures.