Transferable drug resistance in bacteria of coastal canal water and sediment

This study was undertaken to determine the comparative incidence of drug-resistant coliforms and salmonellae in the water and bottom sediments of six coastal canal communities which are used heavily for recreational activities. Of a total of 423 coliforms, 300 fecal coliforms and 100 salmonella isolates examined, 74.9% coliforms, 61.3% fecal coliforms and 71.0% salmonellae were resistant to one or more of the 12 antibiotics tested. Multiple resistance occurred in 48.9% coliforms, 32.7% fecal coliforms and 68.0% salmonella strains. A total of 178 coliforms, 137 fecal coliforms and 51 salmonella isolates were tested for the presence of resistance transfer factors, and 53.9%, 53.3% and 56.9% isolates, respectively, were capable of transferring their resistance patterns to Escherichia coli and/or Salmonella choleraesuis recipient strains. A significantly higher number of drug-resistant bacteria carrying R-factors (R⁺) was found to occur in sediment than in surface water.