scholarly journals Prolonged treatment of Salmonella enterica serovar Typhimurium with commercial disinfectants selects for multiple antibiotic resistance, increased efflux and reduced invasiveness

2007 ◽  
Vol 60 (5) ◽  
pp. 947-955 ◽  
Author(s):  
K. A. G. Karatzas ◽  
M. A. Webber ◽  
F. Jorgensen ◽  
M. J. Woodward ◽  
L. J. V. Piddock ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Prolonged Treatment ◽  
Multiple Antibiotic Resistance ◽  
Serovar Typhimurium

scholarly journals Evidence for an Efflux Pump Mediating Multiple Antibiotic Resistance in Salmonella enterica Serovar Typhimurium

2000 ◽  
Vol 44 (11) ◽  
pp. 3118-3121 ◽  
Author(s):  
Laura J. V. Piddock ◽  
David G. White ◽  
Karl Gensberg ◽  
Lilian Pumbwe ◽  
Deborah J. Griggs
Keyword(s):  
Antibiotic Resistance ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Efflux Pump ◽  
Northern Blotting ◽  
Multiple Antibiotic Resistance ◽  
Reverse Transcription Pcr ◽  
Carbonyl Cyanide ◽  
Serovar Typhimurium

ABSTRACT The mechanism of multiple antibiotic resistance in six isolates ofSalmonella enterica serovar Typhimurium recovered from a patient treated with ciprofloxacin was studied to investigate the role of efflux in the resistance phenotype. Compared to the patient's pretherapy isolate (L3), five of six isolates accumulated less ciprofloxacin, three of six isolates accumulated less chloramphenicol, and all six accumulated less tetracycline. The accumulation of one or more antibiotics was increased by carbonyl cyanidem-chlorophenylhydrazone to concentrations similar to those accumulated by L3 for all isolates except one, in which accumulation of all three agents remained approximately half that of L3. All isolates had the published wild-type sequences of marO andmarR. No increased expression of marA,tolC, or soxS was observed by Northern blotting; however, three isolates showed increased expression ofacrB, which was confirmed by quantitative competitive reverse transcription-PCR. However, there were no mutations withinacrR or the promoter region of acrAB in any of the isolates.

scholarly journals Multiple Antibiotic Resistance (mar) Locus in Salmonella enterica Serovar Typhimurium DT104

2001 ◽  
Vol 67 (3) ◽  
pp. 1190-1197 ◽  
Author(s):  
Luke P. Randall ◽  
Martin J. Woodward
Keyword(s):  
Antibiotic Resistance ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Growth Conditions ◽  
Multiple Antibiotic Resistance ◽  
Independent Manner ◽  
E Coli ◽  
Low Level ◽  
Serovar Typhimurium ◽  
Ca 50

ABSTRACT In order to understand the role of the mar locus inSalmonella with regard to multiple antibiotic resistance, cyclohexane resistance, and outer membrane protein F (OmpF) regulation, a marA::gfp reporter mutant was constructed in an antibiotic-sensitive Salmonella entericaserovar Typhimurium DT104 background. Salicylate inducedmarA, whereas a number of antibiotics, disinfectants, and various growth conditions did not. Increased antibiotic resistance was observed upon salicylate induction, although this was shown to be by both mar-dependent and mar-independent pathways. Cyclohexane resistance, however, was induced by salicylate by a mar-dependent pathway. Complementation studies with a plasmid that constitutively expressed marA confirmed the involvement of mar in Salmonella with low-level antibiotic resistance and cyclohexane resistance, although the involvement of mar in down regulation of OmpF was unclear. However, marA overexpression did increase the expression of a ca. 50-kDa protein, but its identity remains to be elucidated. Passage of the marA::gfp reporter mutant with increasing levels of tetracycline, a method reported to select for mar mutants in Escherichia coli, led to both multiple-antibiotic and cyclohexane resistance. Collectively, these data indicate that low-level antibiotic resistance, cyclohexane resistance, and modulation of OMPs in Salmonella, as inE. coli, can occur in both a mar-dependent andmar-independent manner.

scholarly journals Assessment of Antibiotic Resistance Phenotype and Integrons in Salmonella enterica serovar Typhimurium Isolated from Swine

2008 ◽  
Vol 70 (10) ◽  
pp. 1133-1137 ◽  
Author(s):  
Nabin RAYAMAJHI ◽  
Sang Gyun KANG ◽  
Mi Lan KANG ◽  
Hee Soo LEE ◽  
Kyung Yoon PARK ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Salmonella Enterica ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Resistance Phenotype ◽  
Serovar Typhimurium

scholarly journals Antibiotic Resistance in Salmonella enterica Serovar Typhimurium Exposed to Microcin-Producing Escherichia coli

2001 ◽  
Vol 67 (8) ◽  
pp. 3763-3766 ◽  
Author(s):  
Steve A. Carlson ◽  
Timothy S. Frana ◽  
Ronald W. Griffith
Keyword(s):  
Escherichia Coli ◽  
Antibiotic Resistance ◽  
Salmonella Enterica ◽  
Pathogenic Bacteria ◽  
Defense Mechanism ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Multidrug Resistant ◽  
E Coli ◽  
Resistant Phenotype ◽  
Serovar Typhimurium

ABSTRACT Microcin 24 is an antimicrobial peptide secreted by uropathogenicEscherichia coli. Secretion of microcin 24 provides an antibacterial defense mechanism for E. coli. In a plasmid-based system using transformed Salmonella enterica, we found that resistance to microcin 24 could be seen in concert with a multiple-antibiotic resistance phenotype. This multidrug-resistant phenotype appeared when Salmonella was exposed to an E. coli strain expressing microcin 24. Therefore, it appears that multidrug-resistant Salmonellacan arise as a result of an insult from other pathogenic bacteria.

scholarly journals Expression of acrB, acrF, acrD, marA, and soxS in Salmonella enterica Serovar Typhimurium: Role in Multiple Antibiotic Resistance

2004 ◽  
Vol 48 (4) ◽  
pp. 1145-1150 ◽  
Author(s):  
Deborah J. Eaves ◽  
Vito Ricci ◽  
Laura J. V. Piddock
Keyword(s):  
Salmonella Enterica ◽  
Parent Strain ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Transcriptional Activators ◽  
Multiple Antibiotic Resistance ◽  
Antibiotic Resistant ◽  
Variable Effect ◽  
Chromatography Analysis ◽  
Reverse Transcription Pcr ◽  
Serovar Typhimurium

ABSTRACT Comparative reverse transcription-PCR in combination with denaturing high-pressure liquid chromatography analysis was used to determine the levels of expression of soxS, marA, acrF, acrB, and acrD in multiple-antibiotic-resistant (MAR) Salmonella enterica serovar Typhimurium isolates and mutants of S. enterica serovar Typhimurium SL1344 with defined deletions. Posttherapy MAR clinical isolates had increased levels of expression of all genes except soxS. S. enterica serovar Typhimurium SL1344 ΔacrB expressed 7.9-fold more acrF than the parent strain. A strain with an acrF deletion expressed 4.6-fold more acrB. Deletion of acrB and/or acrF resulted in 2.7- to 4.3-fold more marA mRNA and 3.6- to 4.9-fold increases in the levels of expression of acrD but had a variable effect on the expression of soxS. All mutants were hypersusceptible to antibiotics, dyes, and detergents; but the MIC changes were more noticeable for SL1344 with the acrB deletion than for the mutant with the acrF disruption. These mutants had different but overlapping phenotypes, and the concentrations of ciprofloxacin accumulated by the mutants were different. These data suggest that acrB, acrF, and acrD are coordinately regulated and that their expression influences the expression of the transcriptional activators marA and soxS.

scholarly journals Gene Transfer between Salmonella enterica Serovar Typhimurium inside Epithelial Cells

2002 ◽  
Vol 184 (8) ◽  
pp. 2235-2242 ◽  
Author(s):  
Gayle C. Ferguson ◽  
Jack A. Heinemann ◽  
Martin A. Kennedy
Keyword(s):  
Antibiotic Resistance ◽  
Gene Transfer ◽  
Salmonella Enterica ◽  
Genetically Modified Organisms ◽  
Salmonella Enterica Serovar Typhimurium ◽  
Antibiotic Resistance Genes ◽  
Human Cells ◽  
Serovar Typhimurium ◽  
Cultured Human Cells ◽  
Eukaryotic Organisms

ABSTRACT Virulence and antibiotic resistance genes transfer between bacteria by bacterial conjugation. Conjugation also mediates gene transfer from bacteria to eukaryotic organisms, including yeast and human cells. Predicting when and where genes transfer by conjugation could enhance our understanding of the risks involved in the release of genetically modified organisms, including those being developed for use as vaccines. We report here that Salmonella enterica serovar Typhimurium conjugated inside cultured human cells. The DNA transfer from donor to recipient bacteria was proportional to the probability that the two types of bacteria occupied the same cell, which was dependent on viable and invasive bacteria and on plasmid tra genes. Based on the high frequencies of gene transfer between bacteria inside human cells, we suggest that such gene transfers occur in situ. The implications of gene transfer between bacteria inside human cells, particularly in the context of antibiotic resistance, are discussed.

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