Document Detail

Swarm-cell differentiation in Salmonella enterica serovar typhimurium results in elevated resistance to multiple antibiotics.
MedLine Citation:
PMID:  12730171     Owner:  NLM     Status:  MEDLINE    
Although a wealth of knowledge exists about the molecular and biochemical mechanisms governing the swimming motility of Salmonella enterica serovar Typhimurium, its surface swarming behavior has not been extensively characterized. When inoculated onto a semisolid agar medium supplemented with appropriate nutrients, serovar Typhimurium undergoes a morphological differentiation whereby single cells hyperflagellate and elongate into nonseptate, multinucleate swarm cells. Swarm migration is a collective behavior of groups of cells. We have isolated a MudJ insertion mutant of serovar Typhimurium 14028 that failed to swarm under any conditions. The site of the MudJ insertion was determined to be in the pmrK locus within the pmrHFIJKLM operon, which was previously demonstrated to confer resistance to cationic antimicrobial peptides. beta-Galactosidase assays, using the pmrK::lacZ transcriptional fusion, showed increased expression of the pmr operon in swarm cells compared to that in vegetative cells. In concurrence with the expression data, swarm cells exhibited greater tolerance to polymyxin. To compare the profiles of vegetative and swarm-cell resistance to other antibiotics, E-test strips representing a wide range of antibiotic classes were used. Swarm cells exhibited elevated resistance to a variety of antibiotics, including those that target the cell envelope, protein translation, DNA replication, and transcription. These observations, in addition to the dramatic morphological changes associated with the swarming phenotype, provide an intriguing model for examining global differences between the physiological states of vegetative and swarm cells of serovar Typhimurium.
Wook Kim; Teresa Killam; Vandana Sood; Michael G Surette
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of bacteriology     Volume:  185     ISSN:  0021-9193     ISO Abbreviation:  J. Bacteriol.     Publication Date:  2003 May 
Date Detail:
Created Date:  2003-05-05     Completed Date:  2003-06-16     Revised Date:  2013-04-18    
Medline Journal Info:
Nlm Unique ID:  2985120R     Medline TA:  J Bacteriol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  3111-7     Citation Subset:  IM    
Department of Microbiology and Infectious Diseases, University of Calgary, Calgary, Alberta, Canada.
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MeSH Terms
Adaptation, Biological
Anti-Bacterial Agents / pharmacology*
Drug Resistance, Multiple, Bacterial / physiology*
Gene Expression Regulation, Bacterial
Hexosyltransferases / genetics,  metabolism
Movement / physiology
Operon / physiology
Polymyxins / pharmacology
Salmonella typhi
Salmonella typhimurium / cytology*,  drug effects*,  physiology
Transcription, Genetic
beta-Galactosidase / genetics
Reg. No./Substance:
0/Anti-Bacterial Agents; 0/Polymyxins; EC 2.4.1.-/Hexosyltransferases; EC 2.4.1.-/L-Ara4N transferase; EC

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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