This Article Full Text Full Text (PDF) Other Versions of this Article: AAC.01109-06v1 51/4/1333    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Dubois, V. Articles by Quentin, C. Search for Related Content PubMed PubMed Citation Articles by Dubois, V. Articles by Quentin, C.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, April 2007, p. 1333-1340, Vol. 51, No. 4
0066-4804/07/$08.00+0     doi:10.1128/AAC.01109-06
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

High Genetic Stability of Integrons in Clinical Isolates of Shigella spp. of Worldwide Origin

Laboratoire de Microbiologie, Faculté de Pharmacie, Université de Bordeaux 2, Bordeaux, France,¹ Laboratoire de Bactériologie, Hôpital Saint André, Bordeaux, France²

Received 1 September 2006/ Returned for modification 13 November 2006/ Accepted 15 January 2007

Over a 12-year period, 68 Shigella strains (31 S. sonnei, 30 S. flexneri, 4 S. dysenteriae, and 3 S. boydii strains) were collected in a French University Hospital from the stools of patients who generally had a recent history of travel to various parts of the world (91%), particularly Africa (67%). These strains were often resistant (streptomycin, spectinomycin, trimethoprim, tetracycline, and sulfonamides, 66 to 84%; ampicillin and chloramphenicol, 34 to 38%; nalidixic acid, 4%) and even multiresistant (87%), and they generally carried integrons (81%) of class 1 (21%), class 2 (47%), or both (13%). Class 1 integrons were associated with ampicillin resistance due to the production of an OXA-30 ß-lactamase in S. flexneri and S. dysenteriae. Class 2 integrons were associated with trimethoprim resistance in S. sonnei. Class 1 and class 2 integrons were inserted within transposons Tn21 and Tn7, respectively, themselves located on the bacterial chromosome, except in one strain. Class 1 integrons showed an atypical organization consisting of the insertion sequence IS1 at the 3' end instead of the typical 3' conserved segment and two bla_OXA-30 and aadA1 gene cassettes, despite the absence of epidemiological relationships between the strains, and an apparently functional integrase. Class 2 integrons showed the same albeit classical organization with the three dfrA1, sat, and aadA1 gene cassettes. Occasionally, the 3' end was deleted and the aadA1 gene cassette was unexpressed. Thus, integrons contributed only in part to the multidrug resistance of the Shigella strains. The highly conserved organization of integrons might be related to their location within mobile genetic superstructures.

Published ahead of print on 22 January 2007.

This article has been cited by other articles:

• Gassama Sow, A., Diallo, M. H., Gatet, M., Denis, F., Aidara-Kane, A., Ploy, M.-C. (2008). Description of an unusual class 2 integron in Shigella sonnei isolates in Senegal (sub-Saharan Africa). J Antimicrob Chemother 62: 843-844 [Full Text]