Natural Hot Spots for Gain of Multiple Resistances: Arsenic and Antibiotic Resistances in Heterotrophic, Aerobic Bacteria from Marine Hydrothermal Vent Fields

Abstract

dMicroorganisms are responsible for multiple antibiotic resistances that have been associated with resistance/tolerance to heavy metals, with consequences to public health. Many genes conferring these resistances are located on mobile genetic elements, easily exchanged among phylogenetically distant bacteria. The objective of the present work was to isolate arsenic-, antimonite-, and antibiotic-resistant strains and to determine the existence of plasmids harboring antibiotic/arsenic/antimonite resistance traits in phenotypically resistant strains, in a nonanthropogenically impacted environment. The hydrothermal Lucky Strike field in the Azores archipelago (North Atlantic, between 11°N and 38°N), at the Mid-Atlantic Ridge, protected under the OSPAR Convention, was sampled as a metal-rich pristine environment. A total of 35 strains from 8 different species were isolated in the presence of arsenate, arsenite, and antimonite. ACR3 and arsB genes were amplified from the sediment's total DNA, and 4 isolates also carried ACR3 genes. Phenotypic multiple resistances were found in all strains, and 7 strains had recoverable plasmids. Purified plasmids were sequenced by Illumina and assembled by EDENA V3, and contig annotation was performed using the "Rapid Annotation using the Subsystems Technology" server. Determinants of resistance to copper, zinc, cadmium, cobalt, and chromium as well as to the antibiotics ␤-lactams and fluoroquinolones were found in the 3 sequenced plasmids. Genes coding for heavy metal resistance and antibiotic resistance in the same mobile element were found, suggesting the possibility of horizontal gene transfer and distribution of theses resistances in the bacterial population.T he ocean floor near the Azores is constituted in part by the Mid-Atlantic Ridge and a series of extensive hydrothermal vents. The largest hydrothermal vent field known at this time is located at 37°18.5=N, 32°16.5=W, averages 1,700 m in depth, and is named "Lucky Strike" (1). Here, 21 active hydrothermal vents are connected to the thermal anomalies in the subsea floor at the Mid-Atlantic Ridge that are spread over 150 km 2 . The field is primarily made of basalt but also spikes interest due to rich deposits of ores. Temperatures of the field vary from 170°to 324°C (2), diminishing with the distance from the vent outlet due to water circularization with the surrounding cold temperatures characteristic of these depths (around 4°C), which therefore harbor a distinct microbial community. Furthermore, hydrothermal activity at Lucky Strike seems to have been episodic over a long time (2).The nature of the bedrock and the geological events at Lucky Strike vent sites result in smaller concentrations of Rn and heavy metals (Cd, Hg, Cu, Pb, Zn, Fe, and Ag) and less acidic fluids, making it one of the least extreme environments, in a biological perspective, of the Mid-Atlantic Ridge compared to neighboring vent sites (3).Antibiotics in the environment may result from adaptive phenotypic and genotypic responses of the microbiota. Recen...

Pseudomonads from wild free-living sea turtles in Príncipe Island, Gulf of Guinea

“…Also, these turtles can contact other animals that are known reservoirs of resistant bacteria, including pelagic fish (Al-Bahry et al, 2009), wild birds (Stenkat et al, 2014), and sea mammals (Fertl and Fulling, 2007). Therefore, antibiotic resistance can be commonly found in several natural habitats, not necessarily being related with anthropogenic antibiotic administration and application (Farias et al, 2015). Although the presence of ABR Pseudomonas in turtles and tortoises was already described by several studies (Al-Bahry et al 2009Barbour et al, 2007;Foti et al, 2009), we did not confirm the presence of MDR pseudomonad strains in this region.…”

“…The major concern regarding Pseudomonas species is their antibiotic resistance (ABR) ability, as they are intrinsically resistant to several antibiotic classes, but are also able to express acquired resistance traits due to mutations targeting chromosomal genes, efflux pumps, peptidoglycan-recycling genes, porins, topoisomerases and lipopolysaccharides, or due to acquisition of horizontally transferred resistance genes (Oliver et al, 2015). It is also important to refer that these resistant traits can be horizontally transferred to other bacterial species through mobile genetic elements, easily exchanged among phylogenetically distant bacteria, representing an extra concern (Al-Bahry et al, 2009;Farias et al, 2015).…”

“…Both sea turtles, E. imbricata and C. mydas, have extensive migratory routes (Camacho et al, 2013;González-Garza et al, 2015;Monzón-Argüello et al, 2011;Orós et al, 2005;Whiting et al, 2008), increasing the probability of contacting with waste products including antibiotic residues, oil spills, heavy metals and pesticides (Al-Bahry et al, 2012;Warwick et al, 2013), which can select for resistant strains (Farias et al, 2015;Foti et al, 2009). Regarding their feeding habits, both species are omnivorous, although preferring sponges and algae (Shuyler et al, 2013;Warwick et al, 2013), which can accumulate chemicals and toxic wastes.…”

Heavy-Metal-Resistant Microorganisms in Deep-Sea Sediments Disturbed by Mining Activity: An Application Toward the Development of Experimental in vitro Systems

“…However, our study is one of the first (Wang et al, 2018) in which cultivated deep-sea sediment bacteria from the CCZ were characterized in the laboratory in combination with assessment of their metals resistance and related gene repertoire. Comparable studies have been done in other deep-sea ecosystems such as hydrothermal vent or abyssal plain from different ocean in the world (Farias et al, 2015;Zhang et al, 2015).…”

Exposure to Arsenic Alters the Microbiome of Larval Zebrafish

“…Mounting concern over arsenic contamination in drinking water has led to a better understanding of both arsenic's negative outcomes on human health (Smith et al, 2000 ) and its influence on microbial communities in the environment (Cai et al, 2009 ; Sarkar et al, 2012 ; Escudero et al, 2013 ; Bhadury, 2014 ; Farias et al, 2015 ; Paul et al, 2015 ; Sultana et al, 2017 ). In this study, we investigated whether environmental concentrations of arsenic can perturb microbiota in developing zebrafish larvae.…”