Molecular mechanisms of heavy metal resistance and cross-/co-resistance to antibiotics in Pseudomonas aeruginosa.

Heavy metal pollution is a growing environmental and public health concern, particularly due to its impact on microbial communities. Pseudomonas aeruginosa, a highly adaptable bacterium, has developed resistance to heavy metals (HMs), which is closely linked to antibiotic resistance through shared genetic and regulatory pathways. This co-resistance poses significant challenges for environmental health and antimicrobial management. Additionally, microplastics act as carriers for HMs and antibiotics, creating a compounded pollution stressor that further influences bacterial resistance patterns. This review explores the molecular mechanisms by which P. aeruginosa resists heavy metal toxicity, focusing on key adaptive strategies such as efflux systems, biofilm formation, enzymatic detoxification, and genetic modifications. These mechanisms enhance bacterial survival in contaminated environments, allowing P. aeruginosa to persist and contribute to the spread of resistance genes. The interplay between HMs, antibiotics, and microplastics underscores the complexity of pollution-driven bacterial adaptation. Addressing these issues requires a multidisciplinary approach that integrates environmental pollution control and antimicrobial resistance management. Understanding how P. aeruginosa thrives under such stress conditions is crucial for developing effective strategies to mitigate the risks associated with heavy metal contamination, antibiotic resistance, and microplastic pollution in both natural and clinical ecosystems.