Genetic diversity of Listeria monocytogenes isolates in Colombia from 2010 until 2017 and comparison against the PulseNet regional surveillance network

Introduction. Listeriosis is a food-borne disease associated with Listeria monocytogenes, with high mortality in individuals with weakened immune systems. In Colombia, notification of the disease is not mandatory. Objective. To characterize phenotypically and genomically the clinical isolates of L. monocytogenes isolated from 2010 to 2017 in Colombia. Materials and methods. A total of 63 of the 443 isolates of L. monocytogenes were analyzed by laboratory surveillance of the Grupo de Microbiología at the Instituto Nacional de Salud. Antimicrobial susceptibility, serological test (O-H) antigens and PCR, pulsed-field gel electrophoresis (PFGE)-ApaI enzyme as well as whole genome sequencing (WGS) were performed. Fatalities attributed to L. monocytogenes were identified using SIVIGILA. Results. An estimated 50.73% of the isolates were females, in adults ≥ 15 years old (54%) and were recovered from blood cultures (58.7%), sensitive to penicillin and to trimethoprimsulfamethoxazole. Of the isolates, 77.8% were of the complex serogroup 4b-4d-4e; 42 patterns PFGE-ApaI were determined. Genomic sequencing of five isolates identified multilocus sequencing typing (MLST) ST1, ST2, ribosomal MLST (rMLST) 15992, 15983, 15959, 98481, clonal complex CC1, CC2, lineage I, and serotype 4b in silico. Virulence genes identified included pathogenicity island LIPI-1, LIPI-3 and internalins. Resistance genes included fosX, fosS-2, lin, norB and mprF. The plasmid J1776, and prophages vB_LmoS_293, LP_030_2, LP_030_3, A118 were identified. Global phylogenetic analysis identified that the closest sequences belonged to lineage I, and were from France, Chile, Perú and India. Conclusions. Strengthening epidemiological and laboratory surveillance would improve the control measures in public health.