Heavy Metal Induced Antibiotic Resistance in Bacterium LSJC7

Abstract

Co-contamination of antibiotics and heavy metals prevails in the environment, and may play an important role in disseminating bacterial antibiotic resistance, but the selective effects of heavy metals on bacterial antibiotic resistance is largely unclear. To investigate this, the effects of heavy metals on antibiotic resistance were studied in a genome-sequenced bacterium, LSJC7. The results showed that the presence of arsenate, copper, and zinc were implicated in fortifying the resistance of LSJC7 towards tetracycline. The concentrations of heavy metals required to induce antibiotic resistance, i.e., the minimum heavy metal concentrations (MHCs), were far below (up to 64-fold) the minimum inhibition concentrations (MIC) of LSJC7. This finding indicates that the relatively low heavy metal levels in polluted environments and in treated humans and animals might be sufficient to induce bacterial antibiotic resistance. In addition, heavy metal induced antibiotic resistance was also observed for a combination of arsenate and chloramphenicol in LSJC7, and copper/zinc and tetracycline in antibiotic susceptible strain Escherichia coli DH5α. Overall, this study implies that heavy metal induced antibiotic resistance might be ubiquitous among various microbial species and suggests that it might play a role in the emergence and spread of antibiotic resistance in metal and antibiotic co-contaminated environments.

Synthesis and Bioactivity of Silver Nanoparticles Against Bacteria (<i>E. coli</i> and <i>Enterococcus sp. </i>) Isolated from Kalamu River, Kinshasa City, Democratic Republic of the Congo

“…Determination of some heavy metals. Of the whole list of chemical elements measured following the hypothesis of the current study, only four chemical elements were reported as being heavy metals notably Cu, Cd, Zn and Hg of environmental importance as involved in the resistance of microorganisms as previously described [39].…”

“…One possible explanation of such improvement of antibiotic resistance is that the presence of heavy metals enhanced the enrichment and growth of indigenous bacteria in the microbial community, which are already bearing antibiotic resistance genes; another possibility is that the resistance in bacteria which is sensitive to antibiotics could be induced due to the co-existence of heavy metals and antibiotics in the environment. Some investigations have demonstrated the positive correlation between the abundance of antibiotic resistance genes and the elevated concentrations of antibiotic and heavy metals in environments [39]. We have to note that the environment acts both as a reservoir of resistance traits and a bioreactor containing chemical stressors and opportunities for genetic exchange.…”

“…In some natural environments with microbial communities, combined contaminations of heavy metals and antibiotics contribute to the occurrence and spread of microbial antibiotic resistance; and sometimes multidrug resistance evolves [39]. Some instances are: the co-exposure to Zn and antibiotics such as oxytetracycline in activated sludge bioreactors appears to improve the resistance of the microbial community towards antibiotics.…”

“…The amendment of Cu in agricultural soils selects for Cu resistance and further coselects for resistance to ampicillin, chloramphenicol and tetracycline. Cd in combination with Ni increased the frequency of bacterial resistance in microcosms to chemically unrelated antibiotics like ampicillin or chloramphenicol [39]. One possible explanation of such improvement of antibiotic resistance is that the presence of heavy metals enhanced the enrichment and growth of indigenous bacteria in the microbial community, which are already bearing antibiotic resistance genes; another possibility is that the resistance in bacteria which is sensitive to antibiotics could be induced due to the co-existence of heavy metals and antibiotics in the environment.…”

A comprehensive phylogenetic analysis of copper transporting P1B ATPases from bacteria of the Rhizobiales order uncovers multiplicity, diversity and novel taxonomic subtypes

“…Although our study is based on P 1B -type-ATPases that confer resistance to metals, the analysis of multiplicity and diversity of transporters have general implications for the evolution of resistance, adaptation and innovation in bacteria. For instance, the co-existence of antibiotics and metals in the environment has conducted to the co-evolution of their mechanisms of resistance; the antibiotic resistance induced by exposure to toxic metals is well documented (Berg, Tom-Petersen, & Nybroe, 2005;Chen et al, 2015;Stepanauskas et al, 2006). Furthermore, metals and antibiotic resistance genes tend to cooccurr (Pal, Bengtsson-Palme, Kristiansson, & Larsson, 2015;Su, Ye, & Zhu, 2012).…”