Heavy Metal Resistance Determinants of the Foodborne Pathogen Listeria monocytogenes Original paper
Researched by:
-
Divine Aleru
ID
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.
-
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.
-
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 reviewed?
This review examined the mechanisms by which Listeria monocytogenes resists heavy metals, particularly focusing on the resistance to toxic metals like arsenic and cadmium. It highlights the role of metal resistance determinants in the environmental persistence and virulence of Listeria monocytogenes, with a special focus on their genetic regulation and association with virulence factors.
Who was reviewed?
The review primarily focused on Listeria monocytogenes, specifically its ability to resist heavy metals such as arsenic and cadmium. The study also looked at various Listeria species, with an emphasis on understanding the genetic determinants involved in metal resistance, particularly in relation to foodborne outbreaks and clinical cases of listeriosis.
What were the most important findings?
The review identified several key findings regarding the resistance of Listeria monocytogenes to arsenic and cadmium. Arsenic resistance was found to be most commonly associated with Listeria monocytogenes serotype 4b, particularly in epidemic clones, and was primarily mediated by a genetic island known as LGI2, which carries arsenic resistance genes. Cadmium resistance was found to be prevalent in serotypes 1/2a and 1/2b, often associated with food processing environments. The review discussed the presence of various cadmium resistance genes, such as cadA1, cadA2, and cadA4, located both chromosomally and on plasmids, with a focus on the role of cadA1 and cadA2 in facilitating cadmium resistance. It was noted that the presence of these genes, especially in food isolates, could contribute to the pathogen’s persistence in food processing environments. Moreover, the review highlighted that the resistance to arsenic and cadmium may be linked to the pathogen’s ability to survive in contaminated environments, which could indirectly affect its virulence. The involvement of metal resistance determinants in other cellular functions, such as stress tolerance and biofilm formation, was also discussed.
What are the greatest implications of this review?
The findings of this review have significant implications for food safety and clinical treatment of Listeria monocytogenes. The identification of metal resistance determinants, particularly in relation to food isolates, suggests that resistance to arsenic and cadmium could contribute to the pathogen’s persistence in food processing facilities, posing a challenge for food safety protocols. Furthermore, the genetic elements involved in heavy metal resistance could also be linked to other virulence factors, which may enhance the pathogenicity of Listeria monocytogenes. These insights emphasize the need for continued surveillance of Listeria strains, especially in food production settings, to monitor the spread of resistance traits. The potential for horizontal gene transfer of these resistance elements also underscores the importance of understanding how such genes may contribute to the dissemination of resistance across different bacterial species, which could complicate treatment strategies and food safety efforts.
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.
Arsenic (As)
Arsenic can disrupt both human health and microbial ecosystems. Its impact on the gut microbiome can lead to dysbiosis, which has been linked to increased disease susceptibility and antimicrobial resistance. Arsenic's ability to interfere with cellular processes, especially through its interaction with essential metals like phosphate and zinc, exacerbates these effects.
Cadmium (Cd)
Cadmium (Cd) is a highly toxic heavy metal commonly found in industrial, agricultural, and environmental settings. Exposure to cadmium can occur through contaminated water, food, soil, and air, and it has been linked to a variety of health issues, including kidney damage, osteoporosis, and cancer. In agriculture, cadmium is often present in phosphate fertilizers and can accumulate in plants, entering the food chain. Its toxicity to living organisms makes cadmium a subject of regulatory concern worldwide, particularly in industrial waste disposal and environmental monitoring.