Editor: Eva Top
Gene cassettes and cassette arrays in mobile resistance integrons
Article first published online: 15 APR 2009
© 2009 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved
FEMS Microbiology Reviews
Volume 33, Issue 4, pages 757–784, July 2009
How to Cite
Partridge, S. R., Tsafnat, G., Coiera, E. and Iredell, J. R. (2009), Gene cassettes and cassette arrays in mobile resistance integrons. FEMS Microbiology Reviews, 33: 757–784. doi: 10.1111/j.1574-6976.2009.00175.x
- Issue published online: 3 JUN 2009
- Article first published online: 15 APR 2009
- Received 5 August 2008; revised 17 February 2009; accepted 18 February 2009.Final version published online 15 April 2009.
- gene cassette;
- antibiotic resistance;
- computer-aided discovery
Gene cassettes are small mobile elements, consisting of little more than a single gene and recombination site, which are captured by larger elements called integrons. Several cassettes may be inserted into the same integron forming a tandem array. The discovery of integrons in the chromosome of many species has led to the identification of thousands of gene cassettes, mostly of unknown function, while integrons associated with transposons and plasmids carry mainly antibiotic resistance genes and constitute an important means of spreading resistance. An updated compilation of gene cassettes found in sequences of such ‘mobile resistance integrons’ in GenBank was facilitated by a specially developed automated annotation system. At least 130 different (<98% identical) cassettes that carry known or predicted antibiotic resistance genes were identified, along with many cassettes of unknown function. We list exemplar GenBank accession numbers for each and address some nomenclature issues. Various modifications to cassettes, some of which may be useful in tracking cassette epidemiology, are also described. Despite potential biases in the GenBank dataset, preliminary analysis of cassette distribution suggests interesting differences between cassettes and may provide useful information to direct more systematic studies.