Pseudoalteromonas sp. CuT4-3, a copper resistant bacterium, was isolated from deep-sea hydrothermal sulfides on the Southwest Indian Ridge (SWIR), is an aerobic, mesophilic and rod-shaped bacterium belonging to the family Pseudoalteromonadaceae (class Gammaproteobacteria, order Alteromonadales). In this study, we present the complete genome sequence of strain CuT4-3, which consists of a single circular chromosome comprising 3,660,538 nucleotides with 41.05% G + C content and two circular plasmids comprising 792,064 nucleotides with 40.36% G + C content and 65,436 nucleotides with 41.50% G + C content. In total, 4078 protein coding genes, 105 tRNA genes, and 25 rRNA genes were obtained. Genomic analysis of strain CuT4-3 identified numerous genes related to heavy metal resistance (especially copper) and EPS production. The genome of strain CuT4-3 will be helpful for further understanding of its adaptive strategies, particularly its ability to resist heavy metal, in the deep-sea hydrothermal vent environment.

Vibrio is an important human and animal pathogen that can carry clinically relevant antibiotic resistance genes and is present in different aquatic environments. However, there is a knowledge gap between antibiotic and heavy metal resistance and virulence potential when it is part of the microbiota from marine invertebrates. Here, we aimed to evaluate these characteristics and the occurrence of mobile genetic elements. Of 25 non-cholera Vibrio spp. from marine sponges and sea urchins collected at the coastlines of Brazil and France analyzed in this study, 16 (64%) were non-susceptible to antibiotics, and two (8%) were multidrug-resistant. Beta-lactam resistance (blaSHV) and virulence (vhh) genes were detected in sponge-associated isolates. The resistance gene for copper and silver (cusB) was detected in one sea urchin isolate. Plasmids were found in 11 (44%) of the isolates. This new information allows a better comprehension of antibiotic resistance in aquatic environments, since those invertebrates host resistant Vibrio spp. Thus, Vibrio associated with marine animals may pose a potential risk to public health due to carrying these antibiotic-resistant genes.

It is necessary to study the mechanism of resistance to heavy metals in microbiological processes. In this study, Ochrobactrum MT180101 was used as the microbial source of an membrane bioreactor to investigate its degradation efficiency for electroplating wastewater and the copper-resistant mechanism. Meanwhile, excitation emission matrix-parallel factor, scanning electron microscope, atomic force microscope, fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and proteome analyses were applied to explain the comprehensive mechanism of the Ochrobactrum MT180101 resisting heavy metal toxicity. The results indicated that the Ochrobactrum MT180101 resisted heavy metal toxicity with the following pathways: i) binding metal cations on cell wall surfaces, ii) generating microbial products such as protein to chelate and stabilize the metal cations, iii) bio-transporting heavy metals from the intramembrane to the outer membrane by means of intracellular transport, and iv) reducing heavy metals through enzyme-mediated biotransformation. The results ensure that Ochrobactrum MT180101 was a copper-resistant bacterium that can be used in the pretreatment or deep treatment of electroplating wastewater.