Influence of Abiotic Factors in the Emergence of Antibiotic Resistance

Abstract

Antimicrobial resistance (AMR) has been recognized as a global challenge as many diseases are becoming difficult to treat with the existing drugs. Rapid spread of AMR in several species of bacteria has been an added factor for the higher rates of morbidity and mortality. There are evidences that show human pathogens have acquired antimicrobial resistance genes (ARGs) from environmental bacteria. Many findings have shown the existence of strong correlation between bacterial metal and pesticide tolerance and multidrug resistance (MDR). Application of sewage sludge and animal manure in agricultural lands to improve the soil property and fertility is considered cost-effective and a means to recycle biodegradable wastes. However, sludge and manure have been identified as sources of heavy metals, antibiotics, and AMR genes. Micro−/nanoplastics are the major contaminants identified as vectors for attachment and survival/proliferation of organisms. This microenvironment forms a good niche for genetic exchange between attached biofilm communities, causing the transfer and spread of virulence and AMR genes. Several anthropogenic antimicrobial chemicals such as triclosan and triclocarban leave long-lasting residues. Biocide resistance in bacteria to these chemicals directly induces transcription of osmotic stress response pathways and nonspecific efflux pumps. These chemicals potentially stimulate the conjugative transfer of plasmid-encoded MDR genes within and across the bacterial species. The ecosystem is continuously exposed to a wide variety of chemicals and antimicrobials, which act as a source for the spread of ARGs. Several recent investigations have helped us understand the dynamic environmental factors in the spread of ARGs.