Pulsed field gel electrophoresis (PFGE) in Yersinia enterocolitica strains isolated in San Luis, Argentina.

MASTRODONATO, ANNA CHIARA; IRIARTE, HEBE JORGELINA; ESCUDERO MARÍA ESTHER; LUCERO ESTRADA CECILIA; FAVIER, GABRIELA I.

Mendoza

Congreso; XXX Reunión Científica Anual de la Sociedad de Biología de Cuyo. Sociedad Biología de Cuyo; 2022

Sociedad de Biología de Cuyo

Y. enterocolitica is an enteropathogen transmitted through contaminated food that causes intestinal and extraintestinal diseases in humans. Among the six known biotypes (B), B1A strains have different virulence markers but they are also virulent for human beings. PFGE has been shown to be a highly discriminatory, stable and reproducible subtyping technique, being useful to determine the origin of outbreaks, identify the source and to compare clonal relationships between bacterial strains. It is currently the method of choice for studying the molecular epidemiology of Y. enterocolitica strains isolated from food and clinical samples. In the present work, this technique was used to establish clonal relationship between 24 Y. enterocolitica B1A strains isolated from different origins: human feces, animals intended for human consumption, effluent water and different foods in San Luis, Argentina. The chromosomal DNA preparation and XbaI restriction were performed according to the PFGE protocol standardized by PulseNet (USA). Electrophoresis was carried out using a CHEF-DR III system at 6 V/cm for 20 h at 14°C with the following pulse times: initial time 1.8s and final time 20.0 s. Salmonella Braenderup H9812 and Y. enterocolitica W1024 B2/O:9 were used as DNA size standard and reference strain, respectively. By PFGE, Y. enterocolitica strains were grouped into two large clusters (A and B). The cluster A included Y. enterocolitica B1A strains belonging to different serotypes discriminated in 10 genomic types (GT), while the cluster B included only the reference strain. From cluster A, six GT (60%) grouped more than one isolate of the same serotype, but of different origin (GTA1, GTA3, GTA4, GTA6, and GTA9), with the exception of GTA2, which grouped two isolates from human feces. The remaining GT (GTA5, GTA7, GTA8, and GTA10) included one isolate each (40%). GTA4 was the DNA clonal pattern most frequently found, with five Y. enterocolitica B1A O:7,8-8-8,19 strains included in this group (20.83% of all isolates). The human Y. enterocolitica strains were grouped in GTA2 (two isolates, serotype O:5) and in GTA5 (one isolate, serotype O:7,8-8-8,19), with a similarity of 88%. PFGE analysis showed that most of Y. enterocolitica B1A isolates were discriminated by their serotype and not by their source of origin, resulting in 11 GT defined from 24 isolates and a reference strain, which shows certain homogeneity between the genomic profiles obtained. However, Y. enterocolitica isolates of the same serotype from human feces and food were grouped into different TG. This study demonstrated a high power of discrimination between Y. enterocolitica strains of the same bioserotype which could contribute to the knowledge of the epidemiology of this bacterium and represent a very valuable molecular subtyping tool in our region and worldwide.