Distribution and phenotypic and genotypic characterization of Listeria monocytogenes isolated from food, Colombia, 2010-2018

Abstract

Introduction: Listeria monocytogenes is a food borne pathogen, causing infections such as meningitis, meningoencephalitis, septicemia, abortion, in humans. Serological typing discriminates thirteen serotypes, 4b being the cause of most outbreaks in the world. Objective: To determine in Colombia the frequency and distribution of serotypes and molecular subtypes of L. monocytogenes isolated from food during 20102018. Materials and methods: Retrospective descriptive study. 2,420 isolates were analyzed, confirmed as L. monocytogenes and other species, using biochemical and serological tests and molecular sub typing with pulsed field gel electrophoresis (PFGE). Results: Of the 2,420 isolates received, 2,326 were confirmed as L. monocytogenes. The serotypes found were 4b (52%); 4d-4e (14.5%); 1/2a (11%); 1/2c (9.4%);1/2b (9%); 3a, 3b, 3c, 4c, 4d, 4e and 7 in less than 2%. From Bogotá 43%; Antioquia 25%; Valle 10%; Nariño 9% and other departments 7%. The genotypic characterization grouped the evaluated isolates in 167 PFGE patterns. The most frequent patterns were identified in various dairy and meat products and prepared foods. Conclusion: 96.1% of the isolates corresponding to L. monocytogenes, showing good agreement between isolation and identification. The highest frequency was 4b, a highly virulent serotype. Molecular analysis showed possible dissemination and permanence over time of several serotypes, highlighting the importance of including this pathogen in epidemiological food surveillance programs.