Genomics of IncP-1 antibiotic resistance plasmids isolated from wastewater treatment plants provides evidence for a widely accessible drug resistance gene pool

Abstract

The dramatic spread of antibiotic resistance is a crisis in the treatment of infectious diseases that affect humans. Several studies suggest that wastewater treatment plants (WWTP) are reservoirs for diverse mobile antibiotic resistance elements. This review summarizes findings derived from genomic analysis of IncP-1 resistance plasmids isolated from WWTP bacteria. Plasmids that belong to the IncP-1 group are self-transmissible, and transfer to and replicate in a wide range of hosts. Their backbone functions are described with respect to their impact on vegetative replication, stable maintenance and inheritance, mobility and plasmid control. Accessory genetic modules, mainly representing mobile genetic elements, are integrated in-between functional plasmid backbone modules. These elements carry determinants conferring resistance to nearly all clinically relevant antimicrobial drug classes, to heavy metals, and quaternary ammonium compounds used as disinfectants. All plasmids analysed here contain integrons that potentially facilitate integration, exchange and dissemination of resistance gene cassettes. Comparative genomics of accessory modules located on plasmids from WWTP and corresponding modules previously identified in other bacterial genomes revealed that animal, human and plant pathogens and other bacteria isolated from different habitats share a common pool of resistance determinants.

Spatial structure and nutrients promote invasion of IncP-1 plasmids in bacterial populations

“…Plasmids of the incompatibility group P-1 (IncP-1 plasmids) transfer very efficiently to a wide range of hosts and are abundant in several environments (Thomas and Smith, 1987;Top et al, 2000;Smalla et al, 2006, Schlü ter et al, 2007. They are known to transfer at much higher rates on solid substrates than in mixed liquids.…”

Effects of electron acceptors on removal of antibiotic resistant Escherichia coli, resistance genes and class 1 integrons under anaerobic conditions

“…Both human and livestock excrete antibiotics, antibiotic metabolites, ARBs and ARGs into agricultural waste and domestic wastewater, treatment processes for which are not intentionally designed for their removal, with eventual impact on receiving environments (Hong et al, 2013;Storteboom et al, 2010a;Storteboom et al, 2010b). The activated sludge process in conventional wastewater treatment plants (WWTPs) may create a suitable environment for the proliferation of ARBs and horizontal transfer of ARGs (Moura et al, 2012;Pruden, 2013;Schlüter et al, 2007;Szczepanowski et al, 2009). An elevated level of ARGs has been observed in WWTP effluent after mixed-media filtration and hypochlorite disinfection (LaPara et al, 2011).…”

Lateral genetic transfer: open issues

“…Nonetheless, conjugation between distantly related organisms such as bacteria and eukaryotes (plants and fungi) has been demonstrated experimentally (Heinemann & Sprague 1989); Agrobacterium tumefaciens, for example, can be induced to transfer its Ti plasmid to non-plant hosts including fungi and human cells in culture (Lacroix et al 2006). Plasmids of the self-transmissible IncP-1 group have been isolated from both clinical and environmental (particularly wastewater) settings and harbour a wide range of resistance genes (Schlü ter et al 2007). These plasmids utilize mechanisms that allow their transfer, replication and maintenance in diverse Gram-negative hosts and can mobilize the transfer of other plasmids into an even wider range of target organisms.…”