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Open Access Open Badges Research article

Sulphonamide resistant commensal Neisseria with alterations in the dihydropteroate synthase can be isolated from carriers not exposed to sulphonamides

Yvonne Qvarnström* and Göte Swedberg

Author Affiliations

Department of Medical Biochemistry and Microbiology, Uppsala University, PO Box 582, S-751 23 UPPSALA, SWEDEN

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BMC Microbiology 2002, 2:34  doi:10.1186/1471-2180-2-34

Published: 18 November 2002



Development of sulphonamide resistance in Neisseria meningitidis has been suggested to involve horizontal DNA-transfer from a commensal Neisseria species. In this study, we isolated commensal Neisseria from throat specimens and examined the isolates with respect to sulphonamide resistance.


Three resistant clones were identified and the resistance phenotype could be explained by amino acid variations in their dihydropteroate synthase, the target molecule for sulphonamides. Some of these variations occurred in positions corresponding to previously detected variations in resistant N. meningitidis.


Sulphonamide resistant commensal Neisseria were isolated from an environment not exposed to sulphonamides, suggesting that resistant Neisseria has become a natural part of the commensal throat flora.