Subtyping Brazilian Yersinia pestis strains by pulsed-field gel electrophoresis

Abstract

ABSTRACT. We subtyped Brazilian Yersinia pestis strains by pulsed-field gel electrophoresis (PFGE). This was done with 22 Brazilian Y. pestis strains: 17 from an outbreak and 5 from endemic routine surveillance. The strains were divided into 2 groups (I and II), 8 subgroups (A-H) and 19 PFGE profiles or pulsotypes. PFGE did not separate outbreak from non-outbreak strains, as identical pulsotype patterns were found among outbreak strains and strains obtained from surveillance. However, it was able to detect intraspecific genetic diversity among Brazilian strains. This PFGE technique was able to differentiate a homogeneous group of Brazilian Y. pestis strains.

Dynamics of CRISPR Loci in Microevolutionary Process of Yersinia pestis Strains

“…The molecular data supported the historical evidence of the spread of an ancestral lineage, reinforcing the hypothesis of a single clonal entry into Brazil [10] , [24] . The other genotypes showed distinct subpopulations of Y. pestis that demonstrated bacterial microevolution in these environments.…”

Viability of Yersinia pestis subcultures in agar stabs

“…; Barros et al . , ), the nearly ubiquitous presence of these genes in virulent Y. pestis strains (Perry and Fetherston ), and the isolation of these strains during activities associated with surveillance of active disease, suggesting that all of these strains were originally virulent. It should be noted, however, that possession of all four virulence genes is not necessarily required for virulence (Leal‐Balbino et al .…”

“…Although the original cultures were not screened for the presence of these four virulence genes, it is likely that the genes were present when the cultures were first isolated, making the above assessment a reasonable estimate of the retention frequency of these genes in subcultures stored in this fashion. Supporting this assumption is the general lack of genetic diversity among Y. pestis strains from Brazil (Cavalcanti et al 2002;Barros et al 2013Barros et al , 2014, the nearly ubiquitous presence of these genes in virulent Y. pestis strains (Perry and Fetherston 1997), and the isolation of these strains during activities associated with surveillance of active disease, suggesting that all of these strains were originally virulent. It should be noted, however, that possession of all four virulence genes is not necessarily required for virulence (Leal-Balbino et al 2004).…”

“…; Barros et al . , ). In the course of these various studies, most of the original strain cultures were subcultured and the new subculture tubes kept together with the older subcultures, resulting in multiple stored subcultures of each strain created at different times.…”

“…Various subsets of strains from the Fiocruz-CYP have been studied using a variety of different approaches (e.g. plasmid content, outer membrane protein profile, RAPD, ribotyping, MLVA, PFGE and CRISPR typing), all aimed at enhancing the understanding of the spread and population dynamics of Y. pestis in Brazil (Mello 1970;Burrows and Gillett 1971;Karimi et al 1974;Hudson et al 1976;Abath et al 1989;Leal et al 1997;Cavalcanti et al 2002;Oliveira et al 2012;Barros et al 2013Barros et al , 2014. In the course of these various studies, most of the original strain cultures were subcultured and the new subculture tubes kept together with the older subcultures, resulting in multiple stored subcultures of each strain created at different times.…”