From environment to clinic: the role of pesticides in antimicrobial resistance

Abstract

Antimicrobial resistance (AMR) in pathogens has been associated mainly with excessive use of antibiotics. Most studies of resistance have focused on clinical pathogens; however, microorganisms are exposed to numerous anthropogenic substances. Few studies have sought to determine the effects of chemical substances on microorganisms. Exposure to these substances may contribute to increased rates of AMR. Understanding microorganism communities in natural environments and AMR mechanisms under the effects of anthropogenic substances, such as pesticides, is important to addressing the current crisis of antimicrobial resistance. This report draws attention to molecules, rather than antibiotics, that are commonly used in agrochemicals and may be involved in developing AMR in non-clinical environments, such as soil. This report examines pesticides as mediators for the appearance of AMR, and as a route for antibiotic resistance genes and antimicrobial resistant bacteria to the anthropic environment. Available evidence suggests that the natural environment may be a key dissemination route for antibiotic-resistant genes. Understanding the interrelationship of soil, water, and pesticides is fundamental to raising awareness of the need for environmental monitoring programs and overcoming the current crisis of AMR.

Assessing Environmental Factors within the One Health Approach

“…Anthropogenic activities have led to new challenges for the environment [ 19 ]. Hence, complex issues like AMR must be handled in a coordinated manner.…”

“…This means that fruits and vegetables can be a source for AMR [ 62 , 63 ]. Pesticides may be a pathway for AMR, as some chemical substances may exert a selective pressure favouring antibiotic resistant bacteria [ 19 ]. In the Danish agricultural practice, the use of highly toxic and persistent substances is severely restricted.…”

“…Some herbicides like glyphosate and glufosinate represent telling examples of widespread chemicals with the potential to increase the environmental AMR burden [ 38 ]. The overall use of substances in both animal and plant farming, including the overuse and misuse of antimicrobials as well as some pesticides can therefore act in an additive way [ 19 , 65 ]. Another environmental factor to be considered is the contribution to AMR by toxic metals, which can derive from soil composition, industrial emission or, in the case of copper, also from its use as feed additive [ 11 , 66 ].…”

“…Much thought and actions are needed to optimise the role of environment as the third pillar. Main challenges include how environmental datasets and factors can strengthen the One Health approach for issues such as AMR, as well as how to assess environmental and health issues such as toxic pollutants [ 17 , 19 ].…”

Membrane Disruption Properties of Essential Oils—A Double-Edged Sword?

“…The misuse and overuse of antimicrobial pesticides have further intensified the crisis of antimicrobial resistance in non-clinical environments. A recent report by Malagon-Rojas et al (2020) draws attention to the effects of these chemical substances on microorganisms [64]. The extended use of pesticides has caused the development of a cross-resistance phenomenon [65], because the approach of developing chemicals aimed at eradicating all pathogens has introduced rapid microbial evolution under strong selective pressures.…”