Comparative genomics analyses revealed two virulent Listeria monocytogenes strains isolated from ready-to-eat food

Abstract

Background Listeria monocytogenes is an important foodborne pathogen that causes considerable morbidity in humans with high mortality rates. In this study, we have sequenced the genomes and performed comparative genomics analyses on two strains, LM115 and LM41, isolated from ready-to-eat food in Malaysia.ResultsThe genome size of LM115 and LM41 was 2,959,041 and 2,963,111 bp, respectively. These two strains shared approximately 90% homologous genes. Comparative genomics and phylogenomic analyses revealed that LM115 and LM41 were more closely related to the reference strains F2365 and EGD-e, respectively. Our virulence profiling indicated a total of 31 virulence genes shared by both analysed strains. These shared genes included those that encode for internalins and L. monocytogenes pathogenicity island 1 (LIPI-1). Both the Malaysian L. monocytogenes strains also harboured several genes associated with stress tolerance to counter the adverse conditions. Seven antibiotic and efflux pump related genes which may confer resistance against lincomycin, erythromycin, fosfomycin, quinolone, tetracycline, and penicillin, and macrolides were identified in the genomes of both strains.ConclusionsWhole genome sequencing and comparative genomics analyses revealed two virulent L. monocytogenes strains isolated from ready-to-eat foods in Malaysia. The identification of strains with pathogenic, persistent, and antibiotic resistant potentials from minimally processed food warrant close attention from both healthcare and food industry.

Emergence of Antibiotic Resistance in Listeria monocytogenes Isolated from Food Products: A Comprehensive Review

“…The antibiotic resistance genes tetM and ermB were also identified in L. monocytogenes isolated from fresh mixed sausage and chicken slaughterhouse, respectively (Haubert et al., ). Recently, Lim, Yap, and Thong () found that two L. monocytogenes isolates from fried fish and salad carried five genes including tetA , lmrB , mecC , msrA , and fosX that confer resistance to tetracycline, lincomycin, beta‐lactam, erythromycin, and fosfomycin, respectively. Wilson et al.…”

“…Lim et al. () detected two efflux pump‐related genes, mdrL and lde , which confer resistance to macrolides and quinolone, respectively, in the genomes of two L. monocytogenes isolates from fried fish and salad. In another study, it was suggested that the mutation in the fluoroquinolone efflux protein ( fepA ) regulator, fepR , is responsible in part for the resistance of L. monocytogenes to ciprofloxacin (Wilson et al., ).…”

Metalloriboswitches: RNA-based inorganic ion sensors that regulate genes

“…Overall, the cooperative binding and unique mode of metal recognition by the NiCo riboswitch impart high selectivity, enabling feedback to minute changes in Co 2ϩ or Ni 2ϩ in a milieu of competing cellular ions to confer heavy-metal resistance. Notably, NiCo riboswitches are present in Listeria monocytogenes, a common foodborne pathogen (60) that is of concern because of the identification of multi-antibiotic resistance isolates in "ready-to-eat"' foods (61).…”

Heterogeneity, Characteristics, and Public Health Implications of Listeria monocytogenes in Ready-to-Eat Foods and Pasteurized Milk in China

“…Fluoroquinolone resistance may be mediated by mutations in quinolone resistance-determining regions, including GyrA, GyrB, ParC, and ParE (Bertrand et al, 2016). In addition, the expression of efflux pump FepR, MdeL, and Lde contributed to resistance toward fluoroquinolones (Lismond et al, 2008;Guerin et al, 2014;Lim et al, 2016;Wilson et al, 2018). Vancomycin and novel β-lactams constitute last-line therapy for Listeria infections, and no resistant isolate was observed herein.…”