Cloning and Expression of the Organophosphate Pesticide-Degrading α-ß Hydrolase Gene in Plasmid pMK-07 to Confer Cross-Resistance to Antibiotics.

Pesticide residual persistence in agriculture soil selectively increases the pesticide-degrading population and transfers the pesticide-degrading gene to other populations, leading to cross-resistance to a wide range of antibiotics. The enzymes that degrade pesticides can also catabolize the antibiotics by inducing changes in the gene or protein structure through induced mutations. The present work focuses on the pesticide-degrading bacteria isolated from an agricultural field that develop cross-resistance to antibiotics. This cross-resistance is developed through catabolic gene clusters present in an extrachromosomal plasmid. A larger plasmid (236.7 Kbp) isolated from Bacillus sp. was sequenced by next-generation sequencing, and important features such as α-ß hydrolase, DNA topoisomerase, DNA polymerase III subunit beta, reverse transcriptase, plasmid replication rep X, recombination U, transposase, and S-formylglutathione hydrolase were found in this plasmid. Among these, the α-ß hydrolase enzyme is known for the degradation of organophosphate pesticides. The cloning and expression of the α-ß hydrolase gene imply nonspecific cleavage of antibiotics through a cross-resistance phenomenon in the host. The docking of α-ß hydrolase with a spectrum of antibiotics showed a high G-score against chloramphenicol (-3.793), streptomycin (-2.865), cefotaxime (-5.885), ampicillin (-4.316), and tetracycline (-3.972). This study concludes that continuous exposure to pesticide residues may lead to the emergence of multidrug-resistant strains among the wild microbial flora.

Pesticide degrading natural multidrug resistance bacterial flora.

Multidrug-resistant (MDR) bacteria are a growing threat to humans across the world. Antibiotic resistance is a global problem that has developed through continuous antibiotic use, combinatorial antibiotic use, pesticide-antibiotic cross-resistance, and horizontal gene transfer, as well as various other modes. Pesticide-antibiotic cross-resistance and the subsequent expansion of drug-resistant bacteria are critically documented in this review, the primary focus of which is to assess the impact of indiscriminate pesticide use on the development of microbial communities with parallel pesticide and multidrug resistance. The consumption of pesticide-contaminated food products and the use of broad-spectrum antibiotics by humans and in livestock animals have favored the development of both antibiotic and pesticide-resistant bacterial flora via natural selection. Pesticide resistance mainly develops through defensive bacterial adaptations such as biofilm formation, induced mutations, and horizontal/vertical gene transfer through plasmids or transposons, as well as through the increased expression of certain hydrolytic enzymes. Pesticide resistance genes are always transferred as gene clusters, and they may also carry genes essential for antibiotic resistance. Moreover, for some induced mutations, the mutated active site of the affected enzyme may allow degradation of both pesticides and antibiotics, resulting in cross-resistance. A few studies have shown that the sub-lethal exposure of wild-type strains to herbicides induces antibiotic resistance. This review concludes that xenobiotic exposure leads to cross-resistance in wild microbial flora, which requires further study to develop therapeutic approaches to overcome the threats of MDR bacteria and superbugs.

Emergence of multi drug resistance among soil bacteria exposing to insecticides.

Impacts of pesticide exposure on the soil microbial flora and cross resistance to antibiotics have not been well documented. Development of antibiotic resistance is a common issue among soil bacteria which are exposing to pesticides continuously at sub-lethal concentration. The present study was focused to evaluate the correlation between pesticide exposures and evolution of multi drug resistance among isolates collected from soil applied with insecticides. Twenty five insecticide (Monochrotophos) degrading bacteria were isolated from contaminated agricultural soil. The bacterial isolates Bacillus Sps, Bacillus cereus, Bacillus firmus and Bacillus thuringiensis were found to be resistant against chloramphenical, monochrotophos, ampicillin, cefotaxime, streptomycin and tetracycline antibiotics used. Involvement of plasmid in drug as well as insecticide resistant was confirmed through plasmid curing among selected bacterial strains. Bacillus Sps (MK-07), Bacillus cereus (MK-11), Bacillus firmus (MK-13) and Bacillus thuringiensis (MK-24) lost their resistant against insecticides and antibiotics once after removal of plasmid by exposing to 2% sodium dodecyl sulphate. The plasmid was transformed back to bacteria which produced similar derivatives when cultured in Minimal Salt medium (pH 7.0) supplemented with 0.4% of insecticide. Homology modeling was used to prove that organophosphorus hydrolase and able to metabolize all the antibiotics showed positive interaction with high docking score. The present study revealed that persistent of insecticides in the agricultural soil may lead to increasing development of multidrug resistance among soil bacteria.