Toxin Production and Antibiotic Resistances in Escherichia coli Isolated from Bathing Areas Along the Coastline of the Oslo Fjord

Abstract

The presence of enterovirulent and/or antibiotic resistant strains of Escherichia coli in recreational bathing waters would represent a clear health issue. In total, 144 E. coli isolated from 26 beaches along the inner Oslo fjord were examined for virulence determinants and resistance to clinically important antibiotics. No isolates possessed the genetic determinants associated with enterotoxigenic strains and none showed the prototypic sorbitol negative, O157:H7 phenotype. A small number (∼1 %) produced alpha-hemolysin. Occurrences and patterns of antibiotic resistances were similar to those of E. coli isolated previously from environmental samples. In total, 6 % of the strains showed one or more clinically relevant resistances and 1.4 % were multi-drug resistant. Microarray analyses suggested that the resistance determinants were generally associated with mobile genetic elements. Resistant strains were not clonally related, and were, furthermore not concentrated at one or a few beach sites. This suggests that these strains are entering the waters at a low rate but in a widespread manner. The study demonstrates that resistant E. coli are present in coastal bathing waters where they can come into contact with bathers, and that the resistance determinants are potentially transferable. Some of the resistances registered in the study are to important antibiotics used in human medicine such as fluoroquinolones. The spread of antibiotic resistant genes, from the clinical setting to the environment, has clear implications with respect to the current management of bacterial infections and the long term value of antimicrobial therapy. The present study is the first of its kind in Norway.

Plasmid Replicon Typing of Antibiotic-Resistant Escherichia coli From Clams and Marine Sediments

“…More recently, E. coli has been demonstrated to be highly adaptable and to be able to survive and replicate outside the host, in water, soil, sediment and vegetables (Delaquis et al, 2007;Bergholz et al, 2011;Frank et al, 2011;Jang et al, 2017). Commensal as well as pathogenic E. coli strains resistant to several antibiotics have been recovered in the marine environment (Vignaroli et al, 2013(Vignaroli et al, , 2016Charnock et al, 2014;Drali et al, 2018). Antibiotic resistance in E. coli species is of particular concern because of the growing prevalence of multidrug-resistant (MDR) strains involved in human and animal infections.…”