Phenotypic and genotypic antimicrobial resistance of Listeria monocytogenes: an observational study in France Original paper
Researched by:
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Divine Aleru
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Divine Aleru
Read MoreI am a biochemist with a deep curiosity for the human microbiome and how it shapes human health, and I enjoy making microbiome science more accessible through research and writing. With 2 years experience in microbiome research, I have curated microbiome studies, analyzed microbial signatures, and now focus on interventions as a Microbiome Signatures and Interventions Research Coordinator.
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Microbes
Microbes
Microbes are microscopic organisms living in and on the human body, shaping health through digestion, vitamin production, and immune protection. When microbial balance is disrupted, disease can occur. This guide explains key microbe types—bacteria, viruses, fungi, protozoa, and archaea—plus major pathogenic and beneficial examples.
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Divine Aleru
Read More
Researched by:
-
Divine Aleru
ID
Divine Aleru
Read More
Microbiome Signatures identifies and validates condition-specific microbiome shifts and interventions to accelerate clinical translation. Our multidisciplinary team supports clinicians, researchers, and innovators in turning microbiome science into actionable medicine.
Divine Aleru
What was studied?
This study examined the phenotypic and genotypic antimicrobial resistance (AMR) patterns in Listeria monocytogenes isolates collected in France from 2012 to 2019. It aimed to assess the prevalence of AMR in clinical and food-related isolates, analyze the correlation between genotypic and phenotypic resistance, and evaluate the genetic locations of acquired resistance traits.
Who was studied?
The study focused on Listeria monocytogenes, a foodborne pathogen that causes listeriosis. The isolates analyzed were divided into clinical isolates (2908) and food isolates (2431), all obtained from various regions in France and overseas territories.
What were the most important findings?
The study found that Listeria monocytogenes isolates were resistant to at least three different classes of antimicrobials, a characteristic of their intrinsic resistance. However, acquired resistance was rare, found in only 2.23% of isolates, with food isolates showing a higher prevalence of acquired resistance (3.74%) compared to clinical isolates (0.98%). The most common acquired resistance was against tetracyclines, due to the tetM gene, followed by resistance to macrolides (ermB), lincosamides (lnuG), and phenicols (fexA). The study confirmed that the first-line treatments for listeriosis, such as ampicillin and gentamicin, remain effective, as no acquired resistance to these drugs was observed. Whole genome sequencing (WGS) was used to accurately predict acquired antimicrobial resistance in Listeria monocytogenes isolates, with an accuracy of over 99% for all antibiotics, except for ciprofloxacin. The study also identified that acquired resistance traits were more commonly found in food isolates and were associated with specific genetic elements, such as plasmids and transposons, which could contribute to the spread of resistance.
What are the greatest implications of this study?
The results of this study have significant implications for clinical management and food safety. The low prevalence of acquired resistance in Listeria monocytogenes suggests that current treatment protocols, primarily using aminopenicillins and aminoglycosides, are still effective. However, the higher prevalence of acquired resistance in food isolates highlights the importance of ongoing surveillance in both clinical and food production settings to detect and control the spread of resistant strains. This study also underscores the value of WGS in predicting AMR, which could become a vital tool in future surveillance and outbreak response. The findings emphasize the need for strict monitoring in food production environments to prevent the emergence of new resistance patterns, particularly in Listeria strains that could affect food safety and public health.
Listeria monocytogenes
Listeria monocytogenes is an opportunistic pathogen capable of surviving in diverse environments, including soil, water, and decaying vegetation. L. monocytogenes has the unique ability to evade the immune system by moving directly from cell to cell within the host. This intracellular lifestyle allows the bacterium to avoid extracellular immune detection, contributing to its ability to cause invasive diseases like meningitis and septicemia, particularly in the elderly and immunocompromised.