Transmission of Antibiotic-Resistance Genes by Bacteriophages

[Gert van der Hoek]

Transmission of Antibiotic-Resistance Genes by Bacteriophages

Coliphage DNA isolated from cattle, pig, and poultry waste was found to harbor typical resistance genes in high concentrations.

Bacteria can acquire antibiotic-resistance genes (ARGs) in several ways, including conjugative transfer of mobile elements, transformation by naked DNA, and transduction by bacteriophages. Recent studies have suggested that bacteriophages may be more important in this process than previously believed. To explore this issue, researchers examined the potential role of bacteriophages in spreading ARGs in animal environments.

The study involved 71 fecal waste samples from various animals, collected in slaughterhouses and farms in Spain. Escherichia coli and other fecal coliform bacteria were determined to be present. Coliphage DNA was purified from the samples and tested for resistance genes by conventional and quantitative polymerase chain reaction. ARGs such as blaCTX-M, blaTEM, and mecA were detected in densities as high as 6 log10 gene copies per milliliter or gram of sample.

Comment: The distribution of ARGs by bacteriophages has attracted little attention so far but likely is an important driving force in the spread of antibiotic resistance. Bacteriophages can transmit ARGs even in the absence of antibiotic pressure and are believed to serve as environmental vectors for them. As noted by the authors, phages persist better in aquatic environments (including human and animal wastewater) than their bacterial hosts or free DNA.

— Thomas Glück, MD

Published in Journal Watch Infectious Diseases November 9, 2011

http://infectious-diseases.jwatch.org/cgi/content/full/2011/1109/1?q=etoc_jwid

Bacteriophages carrying antibiotic resistance genes in fecal waste from cattle, pigs, and poultry

Colomer-Lluch M, Imamovic L, Jofre J, Muniesa M.

Source
Department of Microbiology, University of Barcelona, Diagonal 645, Annex, Floor 0, E-08028 Barcelona, Spain. mmuniesa@ub.edu

Abstract
This study evaluates the occurrence of bacteriophages carrying antibiotic resistance genes in animal environments. bla(TEM), bla(CTX-M) (clusters 1 and 9), and mecA were quantified by quantitative PCR in 71 phage DNA samples from pigs, poultry, and cattle fecal wastes.

Densities of 3 to 4 log(10) gene copies (GC) of bla(TEM), 2 to 3 log(10) GC of bla(CTX-M), and 1 to 3 log(10) GC of mecA per milliliter or gram of sample were detected, suggesting that bacteriophages can be environmental vectors for the horizontal transfer of antibiotic resistance genes.

Pubmed

thanks to Dave Roberts for the link