Sequence-based characterization of   Listeria monocytogenes  strains isolated from domestic retail meat in the Tokyo metropolitan area of Japan.

Sequence-based characterization of  Listeria monocytogenes  strains isolated from domestic retail meat in the Tokyo metropolitan area of Japan. Jpn J Infect Dis. 2018 May 31;: Authors: Yoshikawa Y, Ochiai Y, Mochizuki M, Takano T, Hondo R, Ueda F Abstract To assess the level of Listeria monocytogenes contamination of domestic retail meat in Tokyo, Japan, we compared isolates from 2004 to 2007 with those isolated before 2003. The overall prevalence of L. monocytogenes among these samples significantly diminished over time (1998-2003, 28.0%; 2004-2007, 17.6%) reflecting a significant decrease in the frequency of contamination of beef. Serotype 1/2a was isolated most frequently, reflecting a change in the predominant serotype in pork from 1/2c to 1/2a. We performed a simple genetic subtyping method based on three genes, iap, sigB, and actA, as well as traditional multilocus sequence typing to classify the allele types (ATs). No extensive variation among sequence types was detected; however, increased genetic diversity among the ATs of the three genes in the 2004-2007 isolates was evident. We identified AT 26 of the iap gene, not previously reported in Japanese isolates, and six ATs of the sigB gene, including four with nonsense mutations not currently registered in L. monocytogenes DNA databases. sigB is an evolutionally conserved gene that plays a role in the stress response. Our results indicate that the sigB gene may be relatively ...
Source: Japanese Journal of Infectious Diseases - Category: Infectious Diseases Authors: Tags: Jpn J Infect Dis Source Type: research