Contribution of fresh river water to the dissemination of Hospital-Associated Enterococcus faecium CC17 strains in Córdoba

BLASKO ENRIQUE G; GONZÁLEZ M JOSÉ; BARDOSSY ANA C; SOSA EZEQUIEL J; PRENTISS TYLER; SULEYMAN GEEHAN; JAGJEET KAUR; MAKI GINA; RUIZ SUSANA E; GRUPO DE ESTUDIO DE COLONIZACIÓN POR VRE DE CBA; FERNÁNDEZ DO PORTO DARÍO; BOCCO JOSÉ LUIS; SAKA H ALEX; AMÉ VALERIA; ZERVOS MARCUS; SOLA CLAUDIA

ROSARIO

Congreso; LIX Annual Meeting of the Argentine Society for Biochemistry and Molecular Biology Research (SAIB). Congreso SAIB 2023; 2023

SAIB

E. faecium is a bacterium capable of causing serious infections mostly acquired in hospitals. This bacterium is commonly found in the intestine of healthy humans and animals, allowing it to enter the environment through feces. The rise of vancomycin-resistant Enterococcus (VRE) has led to treatment challenges in hospital settings worldwide.Our study aimed to investigate whether fresh river water contributes to the transmission of hospital-associated VRE clonal lineages.We conducted a comprehensive analysis of the antibiotic resistome, virulome, and phylogenomic lineages of vancomycin-resistant E. faecium (VREfm) isolates using whole-genome sequencing (WGS) and bioinformatics tools. The isolates were obtained from various sources, including hospital-acquired infections (n: 3), hospital-associated colonization samples [from rectal swabs (n: 9) and chronic ulcers (n: 1)], and isolates collected from freshwater sources (Suquia River, n: 5) in an area downstream of the Córdoba city and the wastewater treatment plant (WWTP).The antibiotic susceptibility was determined by diffusion/Vitek2, CLSI2019 and the presence of vanA/B genes by PCR. All the VREfm isolates were resistant to vancomycin (vanA+), teicoplanin, ampicillin and ciprofloxacin, with 77.8% presenting resistance to minocycline. VREfm belonged to clonal complex (CC) 17, ST17 (n= 6), ST736 (n= 6), and ST792 (n = 6). Ampicillin resistance was associated with predicted amino acid changes in the PBP5 protein. Most isolates harbored the following resistance genes: macrolides/lincosamides [msr(C), erm(B)], minocycline [tet(M), and tet(L)], aminoglycoside [aac(6)-aph(2), ant(6)-Ia, aph(3)-III, aac(6)-Iid] and trimethoprim (dfrG). Fluoroquinolone resistance was associated with amino acid substitutions in GyrA (Ser84Tyr: 66.7%; n =12) or Ser84Ile: 33.3%; n=6 and ParC (Ser82Arg: 100%; n=18). A total of 23 different virulence genes were identified including those encoding for adhesion (acm, scm, esp, sgrA, fms6 and fms22), capsule (cpsA/uppS, cpsB/cdsA) and biofilm formation (bopD).Phylogenetic analysis revealed two clearly defined groups: one consisted of isolates with the ST17 profile (which grouped the 3 infection isolates and 3 environmental isolates), while the other showed ST736 and ST792 profiles (which grouped the 10 colonization isolates and 2 environmental isolates). Consequently, in both groups, genomes of environmental origin were identified. Moreover, no significant differences were observed in terms of genes related to resistance or virulence between them. These results support the hypothesis that the environment may act as a reservoir and/or means of dissemination for these hospital associated high-risk clones. Therefore, it is essential to prioritize the monitoring of resistance in environmental sources from urban areas and implement wastewater treatment strategies aimed at preventing the release of VRE into the environment.