Antimicrobial resistance and antimicrobial resistance genes in marine bacteria from salmon aquaculture and non‐aquaculture sites

Abstract

Antimicrobial resistance (AR) detected by disc diffusion and antimicrobial resistance genes detected by DNA hybridization and polymerase chain reaction with amplicon sequencing were studied in 124 marine bacterial isolates from a Chilean salmon aquaculture site and 76 from a site without aquaculture 8 km distant. Resistance to one or more antimicrobials was present in 81% of the isolates regardless of site. Resistance to tetracycline was most commonly encoded by tetA and tetG; to trimethoprim, by dfrA1, dfrA5 and dfrA12; to sulfamethizole, by sul1 and sul2; to amoxicillin, by blaTEM ; and to streptomycin, by strA-strB. Integron integrase intl1 was detected in 14 sul1-positive isolates, associated with aad9 gene cassettes in two from the aquaculture site. intl2 Integrase was only detected in three dfrA1-positive isolates from the aquaculture site and was not associated with gene cassettes in any. Of nine isolates tested for conjugation, two from the aquaculture site transferred AR determinants to Escherichia coli. High levels of AR in marine sediments from aquaculture and non-aquaculture sites suggest that dispersion of the large amounts of antimicrobials used in Chilean salmon aquaculture has created selective pressure in areas of the marine environment far removed from the initial site of use of these agents.

The Resistome of Farmed Fish Feces Contributes to the Enrichment of Antibiotic Resistance Genes in Sediments below Baltic Sea Fish Farms

“…The prevalence of resistant bacteria carrying ARGs (Nonaka et al, 2007; Shah et al, 2014) and enrichment of ARGs in sediments below fish farms have been observed globally (Tamminen et al, 2011a; Gao et al, 2012; Muziasari et al, 2014, 2016; Xiong et al, 2015). However, the causes of ARG enrichment in the farm sediments have received very little attention.…”

Occurrence and ecological hazard assessment of selected antibiotics in the surface waters in and around Lake Honghu, China

“…Usually, antibiotics are poorly absorbed and metabolized by the tested organisms (Sarmah et al, 2006); hence, most of these chemicals have ultimately entered the environment via urine and feces, domestic swage, livestock and agriculture wastes, and/or direct splashing to the aquaculture water (Heuer et al, 2008;Yao et al, 2015;Shah et al, 2014). Due to their continuous input into the environment through numerous pollution sources and their degradation-resistant characteristics, antibiotics are regarded as a class of ubiquitous and "pseudo-persistent" contaminants in aquatic environments (Nödler et al, 2012;Yao et al, 2015).…”

Antibiotics, Antibiotic Resistance Genes, and Bacterial Community Composition in Fresh Water Aquaculture Environment in China

“…Although antibiotic resistance is ancient and naturally occurring phenomenon widespread in the environment [3], it is accelerated by antibiotic use in medicine and veterinary. The spread of ARGs in the environment is promoted by anthropogenic activities, such as animal farm [4], waste/wastewater treatment [5], and aquaculture [6]. To our knowledge, ARGs have been investigated in several environmental compartments, such as farm lands [7], rivers [8], and fish ponds [9].…”