Review
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World J Clin Infect Dis. Feb 25, 2013; 3(1): 1-12
Published online Feb 25, 2013. doi: 10.5495/wjcid.v3.i1.1
Extended role for insertion sequence elements in the antibiotic resistance of Bacteroides
József Sóki
József Sóki, Institute of Clinical Microbiology, Albert Szent-Györgyi Clinical Center, Faculty of Medicine, University of Szeged, H-6725 Szeged, Hungary
Author contributions: Sóki J solely contributed to this manuscript.
Supported by The Center of Excellence at the University of Szeged (TÁMOP-421B) to József Sóki
Correspondence to: József Sóki, PhD, Institute of Clinical Microbiology, Albert Szent-Györgyi Clinical Center, Faculty of Medicine, University of Szeged, Semmelweis u. 6., H-6725 Szeged, Hungary. soki.jozsef@med.u-szeged.hu
Telephone: +36-62-545399 Fax: +36-62-545712
Received: September 13, 2012
Revised: December 4, 2012
Accepted: December 15, 2012
Published online: February 25, 2013
Processing time: 237 Days and 22.7 Hours
Abstract

The Bacteroides species are important micro-organisms, both in the normal physiology of the intestines and as frequent opportunistic anaerobic pathogens, with a deeply-rooted phylogenetic origin endowing them with some interesting biological features. Their prevalence in anaerobic clinical specimens is around 60%-80%, and they display the most numerous and highest rates of antibiotic resistance among all pathogenic anaerobes. In these antibiotic resistance mechanisms there is a noteworthy role for the insertion sequence (IS) elements, which are usually regarded as representatives of ‘selfish’ genes; the IS elements of Bacteroides are usually capable of up-regulating the antibiotic resistance genes. These include the cepA (penicillin and cephalosporin), cfxA (cephamycin), cfiA (carbapenem), nim (metronidazole) and ermF (clindamycin) resistance genes. This is achieved by outward-oriented promoter sequences on the ISs. Although some representatives are well characterized, e.g., the resistance gene-IS element pairs in certain resistant strains, open questions remain in this field concerning a better understanding of the molecular biology of the antibiotic resistance mechanisms of Bacteroides, which will have clinical implications.

Keywords: Antibiotic resistance; Antibiotic resistance genes; Bacteroides fragilis; Insertion sequence elements