Culturable bacteria from two Portuguese salterns: diversity and bioactive potential

Salsipaludibacter albus gen. nov., sp. nov., a novel actinobacterial strain isolate from a Portuguese solar saltern and proposal of Salsipaludibacteraceae fam. nov. and Salsipaludibacterales ord. nov.

“…The identification of streptomycin-resistance genes was expected as strain AS10 T was isolated under the selective pressure of streptomycin, which was included in the isolation medium [12]. Ampicillin, a beta-lactam antibiotic, was also used for AS10 T isolation [12] and among all the 199 ‘loose’ hits with lower similarity to AMR genes detected, 34 of them are associated with resistance to penams, where ampicillin is included. The resistance mechanisms of the 199 ‘loose’ hits were distributed between five different groups: antibiotic inactivation (five hits), antibiotic efflux (135 hits), antibiotic target alteration (49 hits), antibiotic target replacement (six hits) and antibiotic target protection (nine hits), and reduced permeability to antibiotic (two hits) (see supplementary data).…”

“…Concerning antibiotic resistance genes, the CARD-RGI database identified the presence of one ‘strict’ match, with a similarity score of 99.19 % and a coverage of 83.61%, associated with a resistance mechanism involving antibiotic target alteration that confers aminoglycosides resistance, specifically to streptomycin. The identification of streptomycin-resistance genes was expected as strain AS10 T was isolated under the selective pressure of streptomycin, which was included in the isolation medium [12]. Ampicillin, a beta-lactam antibiotic, was also used for AS10 T isolation [12] and among all the 199 ‘loose’ hits with lower similarity to AMR genes detected, 34 of them are associated with resistance to penams, where ampicillin is included.…”

“…Untreated dry salt from Aveiro saltern, Portugal, produced in 2015, was kindly provided by ALGAplus (Ílhavo, Portugal) in 2016. The salt was dissolved in sterilized sea water until saturation and inoculated on M600 agar [11] supplemented with 200 µg ml −1 ampicillin (AppliChem), 1 mg ml −1 streptomycin (AppliChem) and 2× spray of a 10 mg g −1 econazole nitrate solution (Johnson and Johnson) that was sprayed onto the surface of the culture medium [12]. Briefly, the M600 agar medium consisted of natural sea water with the following ingredients: 1 g l −1 peptone, 1 g l −1 yeast extract, 1.6% (w/v) agar and 50 ml l −1 0.1 M Tris-HCl pH 7.5; and supplemented with 0.1% glucose (w/v), 10 ml l −1 vitamin solution no.…”

“…DNA extraction and identification through 16S rRNA gene sequencing of strain AS10 T was previously carried out [12]. The obtained sequence was compared with sequences from the EzBioCloud [34] and blast n [35] databases to establish their closest relatives.…”

Antibiotic-Resistant Bacteria across a Wastewater Treatment Plant

“…The extracted genomic DNA was used for the PCR amplification of the 16S rRNA gene using the universal primers 27F and 1492R [22] (Table 1). The PCR mixtures and conditions were prepared as previously described [23] (Table 1). The PCR products were then visualized after electrophoresis in a 0.8% agarose gel in 1X Tris-Acetate-EDTA (TAE) buffer stained with GreenSafe Premium (NZYTech, Lisboa, Portugal).…”