Characterization and comparative analysis of antibiotic resistance plasmids isolated from a wastewater treatment plant

Abstract

A wastewater treatment plant (WWTP) is an environment high in nutrient concentration with diverse bacterial populations and can provide an ideal environment for the proliferation of mobile elements such as plasmids. WWTPs have also been identified as reservoirs for antibiotic resistance genes that are associated with human pathogens. The objectives of this study were to isolate and characterize self-transmissible or mobilizable resistance plasmids associated with effluent from WWTP. An enrichment culture approach designed to capture plasmids conferring resistance to high concentrations of erythromycin was used to capture plasmids from an urban WWTP servicing a population of ca. 210,000. DNA sequencing of the plasmids revealed diversity of plasmids represented by incompatibility groups IncU, col-E, IncFII and IncP-1β. Genes coding resistance to clinically relevant antibiotics (macrolide, tetracycline, beta-lactam, trimethoprim, chloramphenicol, sulphonamide), quaternary ammonium compounds and heavy metals were co-located on these plasmids, often within transposable and integrative mobile elements. Several of the plasmids were self-transmissible or mobilizable and could be maintained in the absence of antibiotic selection. The IncFII plasmid pEFC36a showed the highest degree of sequence identity to plasmid R1 which has been isolated in England more than 50 years ago from a patient suffering from a Salmonella infection. Functional conservation of key regulatory features of this F-like conjugation module were demonstrated by the finding that the conjugation frequency of pEFC36a could be stimulated by the positive regulator of plasmid R1 DNA transfer genes, TraJ.

Horizontal Dissemination of Antimicrobial Resistance Determinants in Multiple Salmonella Serotypes following Isolation from the Commercial Swine Operation Environment after Manure Application

“…The T4SS in Gram-negative bacteria functionally encompass the conjugation system and the effector translocators for interbacterial transfer of AMR genes, virulence determinants, and genes encoding other traits beneficial to the host (67). IncN plasmids (pS6 to pS8) and IncI1 plasmids (pS9 [100-kb] and pS20) employed TraJ, which the has ability to conjugate, and the conjugation process could be stimulated approximately 100-fold, demonstrating functional conservation of a significant regulatory feature of F-like conjugation modules (68).…”

Identification and antimicrobial resistance prevalence of pathogenic Escherichia coli strains from treated wastewater effluents in Eastern Cape, South Africa

“…; Rahube et al. ). Antibiotic‐resistant bacteria and unabsorbed antibiotic residues are excreted in urine and feces, and ultimately travel to wastewater reclamation facilities via domestic sewer lines (Rizzo et al.…”

Regional Dissemination of a Carbapenemase-encoding Plasmid: Plasmidome analysis Reveals Diverse Adaptations of Carbapenemase-Producing Enterobacteriaceae

“…These plasmids were generated by integration of a cassette carrying bla IMP-6 on pKPI-6 into another IncF plasmid at IS26. This IncF plasmid (pEC302/04; Supplementary Figure S6B) has been reported to transmit antimicrobial resistance since 1965 [15].…”