Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “floR”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 55 records · Page 3Linked to original sources
PubMed1982

The oral flor as a source of septicemia in patients with acute leukemia.

This study was performed to determine the role of the oral cavity in causing septicemia in patients with acute leukemia. Thirty-three patients with acute nonlymphocytic leukemia were investigated prospectively via clinical, hematologic, and microbiologic techniques. The mouth was the most likely source of septicemia in seven of twelve cases. Necessary dental treatment prior to chemotherapy was accompanied by a significant reduction in the rate of septicemia. The authors conclude that oral sources of bacteremia should be eliminated prior to chemotherapy in patients with acute leukemia.

Adult↗
PubMed2003

Molecular analysis of florfenicol-resistant Escherichia coli isolates from pigs.

OBJECTIVES: The aim of this study was to analyse florfenicol-resistant Escherichia coli isolates from pigs for the genetic basis of florfenicol resistance, and to compare these data with those previously determined for E. coli isolates from cattle and poultry. METHODS: Fourteen porcine E. coli isolates were included in this study and subjected to serotyping, plasmid profiling and macrorestriction analysis. MICs of florfenicol were determined by broth microdilution. The presence of the gene floR was confirmed by hybridization and PCR analysis. Transformation experiments were conducted to isolate florfenicol resistance plasmids. The floR region of a florfenicol resistance plasmid was cloned and sequenced. RESULTS: All florfenicol-resistant E. coli isolates exhibited MICs of florfenicol >128 mg/L and carried the floR gene. A single isolate had a floR-carrying plasmid of approximately 35 kb, designated pMBSF1. Sequence analysis identified the floR gene flanked by truncated transposase genes. Moreover, a truncated copy of Tn5393 with complete streptomycin resistance genes strA and strB was found upstream of the floR gene of pMBSF1. Chromosomally resistant E. coli isolates, which shared the same BlnI macrorestriction pattern, differed in their floR hybridization patterns. CONCLUSION: The plasmid pMBSF1 is the smallest floR-carrying plasmid reported to date. Its floR region differed from those previously found in E. coli isolates from cattle. Variations in the RFLPs of chromosomal EcoRI fragments carrying floR in isolates that had the same macrorestriction pattern might suggest variable chromosomal integration sites.

Animals↗
PubMed2002

Molecular analysis of chromosomally florfenicol-resistant Escherichia coli isolates from France and Germany.

The aim of this study was to analyse chromosomally florfenicol-resistant Escherichia coli isolates for their genetic relatedness, and also for the presence of the floR gene and its adjacent regions, in order to compare these regions with those associated with a floR gene located on a conjugative plasmid from E. coli. Twenty-two bovine E. coli from France and Germany were examined. Florfenicol resistance was determined by MIC determination. The presence of the floR gene was confirmed by hybridization and PCR analysis. The E. coli isolates were investigated by macrorestriction analysis. The 22 florfenicol-resistant E. coli (MICs 64->128 mg/L) differed in their BlnI macrorestriction patterns. Single or double copies of the floR gene were detected by hybridization on different-sized chromosomal EcoRI, BamHI and BglI fragments. The floR-flanking regions also proved to be variable as confirmed by hybridization experiments. The detection of chromosomal floR gene copies in unrelated E. coli isolates supplements the observations of floR genes on plasmids in E. coli and confirms their potential to integrate into the chromosome. The RFLPs of floR gene-carrying restriction fragments might suggest variable chromosomal integration sites.

Animals↗
PubMed2002

An evaluation of the relative efficacy of a new formulation of oxytetracycline for the treatment of undifferentiated fever in feedlot calves in western Canada.

A field trial was performed under commercial feedlot conditions in western Canada to compare the efficacy of a new formulation of long-acting oxytetracycline (LA 30) to a standard long-acting oxytetracycline formulation (LA 20) and florfenicol (FLOR) for the treatment of undifferentiated fever (UF) in calves that received metaphylactic tilmicosin upon arrival at the feed-lot. Seven hundred and ninety-seven recently weaned, auction market derived, crossbred, beef calves suffering from UF were allocated to 1 of 3 experimental groups as follows: LA 30, which received intramuscular long-acting oxytetracycline (300 mg/mL formulation) at the rate of 30 mg/kg body weight (BW) at the time of allocation; LA 20, which received intramuscular long-acting oxytetracycline (200 mg/mL formulation) at the rate of 20 mg/kg BW at the time of allocation; or FLOR, which received intramuscular florfenicol administered at the rate of 20 mg/kg BW at the time of allocation and again 48 hours later. Two hundred and sixty-six animals were allocated to the LA 30 group, 265 animals were allocated to the LA 20 group, and 266 animals were allocated to the FLOR group. The relative efficacy of the LA 30 group, as compared with the LA 20 and FLOR groups, was assessed by comparing relapse, chronicity, wastage, and mortality rates. The overall mortality (RR = 0.50) rate in the LA 30 group was significantly (P < 0.05) lower than in the LA 20 group. However, the overall chronicity (RR = 2.56) and overall wastage (RR = 6.97) rates of the LA 30 group were significantly (P < 0.05) higher than in the LA 20 group. There were no significant (P > or = 0.05) differences in UF relapse rates or cause specific mortality rates between the LA 30 and LA 20 groups. In the economic analysis, there was an advantage of $28.59 CDN per animal in the LA 30 group compared with the LA 20 group. The overall chronicity (RR = 2.25) and overall wastage (RR = 2.80) rates of the LA 30 group were significantly (P < 0.05) higher than the FLOR group. There were no significant (P > or = 0.05) differences in UF relapse rates, overall mortality rates, or cause specific mortality rates between the LA 30 and FLOR groups. In the economic analysis, there was an advantage of $12.90 CDN per animal in the LA 30 group compared with the FLOR group. In summary, the results of this study indicate that it is more cost-effective to use a new formulation of long-acting oxytetracycline (300 mg/mL formulation administered at a rate of 30 mg/kg BW) than a standard long-acting oxytetracycline formulation (200 mg/mL formulation administered at a rate of 20 mg/kg BW) or florfenicol for the treatment of UF in feedlot calves that have previously received metaphylactic tilmicosin upon arrival at the feedlot.

Animals↗
PubMed2001

Yeast population dynamics during the fermentation and biological aging of sherry wines.

Molecular and physiological analyses were used to study the evolution of the yeast population, from alcoholic fermentation to biological aging in the process of "fino" sherry wine making. The four races of "flor" Saccharomyces cerevisiae (beticus, cheresiensis, montuliensis, and rouxii) exhibited identical restriction patterns for the region spanning the internal transcribed spacers 1 and 2 (ITS-1 and ITS-2) and the 5.8S rRNA gene, but this pattern was different, from those exhibited by non-flor S. cerevisiae strains. This flor-specific pattern was detected only after wines were fortified, never during alcoholic fermentation, and all the strains isolated from the velum exhibited the typical flor yeast pattern. By restriction fragment length polymorphism of mitochondrial DNA and karyotyping, we showed that (i) the native strain is better adapted to fermentation conditions than commercial strains; (ii) two different populations of S. cerevisiae strains are involved in the process of elaboration, of fino sherry wine, one of which is responsible for must fermentation and the other, for wine aging; and (iii) one strain was dominant in the flor population integrating the velum from sherry wines produced in González Byass wineries, although other authors have described a succession of races of flor S. cerevisiae during wine aging. Analyzing all these results together, we conclude that yeast population dynamics during biological aging is a complex phenomenon and differences between yeast populations from different wineries can be observed.

DNA, Bacterial↗
PubMed2004

Characterization of florfenicol resistance among calf pathogenic Escherichia coli.

Three floR genes were cloned from calf pathogenic Escherichia coli strains, and the efflux-mediated accumulation of florfenicol in the floR gene-JM109 E. coli system was determined by HPLC. The floR genes resulted in a 1356-bp fragment covering the ORF in region 66-1280 coding for 404 amino acids. The common motifs of 12-transmembrane segments efflux pumps family were conserved in the deduced floR amino acid sequences. HPLC results indicated a significant difference in florfenicol accumulation between florfenicol-resistant strains and the susceptible strains, which was almost reversed by the addition of a proton motive force blocker. These results suggest that the florfenicol resistance mediated by the floR gene involves active efflux of florfenicol.

Amino Acid Sequence↗
PubMed2007

Efflux-mediated resistance to florfenicol and/or chloramphenicol in Bordetella bronchiseptica: identification of a novel chloramphenicol exporter.

OBJECTIVES: Twenty florfenicol- and/or chloramphenicol-resistant Bordetella bronchiseptica isolates of porcine and feline origin were investigated for the presence of floR and cml genes and their location on plasmids. METHODS: The B. bronchiseptica isolates were investigated for their susceptibility to antimicrobial agents by broth micro- or macrodilution and for their plasmid content. Hybridization experiments and PCR assays were conducted to identify resistance genes. Transformation and conjugation studies were performed to show their transferability. Representatives of both types of genes including their flanking regions were sequenced. Moreover, inhibitor studies with the efflux pump inhibitor Phe-Arg-beta-naphthylamide (PAbetaN) were performed. RESULTS: The gene floR was found in the chromosomal DNA of 9 of the 18 florfenicol/chloramphenicol-resistant isolates. Sequence analysis revealed that the deduced FloR protein sequence differed by a single amino acid exchange from FloR of Vibrio cholerae. A chloramphenicol-resistant, but florfenicol-susceptible isolate carried a novel plasmid-borne cml gene, designated cmlB1. The CmlB1 protein revealed only 73.8-76.5% identity to known CmlA proteins. The gene cmlB1 was not part of a gene cassette. The results of inhibitor studies with PAbetaN suggested that a so-far unidentified efflux system might play a role in phenicol resistance of the remaining florfenicol- and/or chloramphenicol-resistant isolates. CONCLUSIONS: This is to the best of our knowledge the first report of a floR gene in B. bronchiseptica isolates. The identification of the first member of a new subclass of cml genes, cmlB1 from B. bronchiseptica, extends our knowledge on specific chloramphenicol exporters.

Amino Acid Sequence↗
PubMed1996

Genomic complexity and chromosomal rearrangements in wine-laboratory yeast hybrids.

In this report we describe the genomic complexity of a number of Saccharomyces yeast strains isolated from sherry wine (flor yeasts), and the genomic stability of a yeast hybrid derived from one of these and a laboratory strain. Flor yeast strains largely differed in their DNA content, but showed very few variations their molecular karyotype. These strains contained a large number of Ty2 sequences, but lacking the Ty1 elements commonly found in laboratory strains. The genetic analysis of a flor-laboratory hybrid indicated that flor yeasts were aneuploid. Hybridization patterns obtained with Ty1 and Ty2 probes in the meiotic progeny of this hybrid suggested that recombination may occur not only among homologous chromosomes of similar length, but also among polymorphic partners with different sizes. New chromosomal variants were frequently observed in the meiotic products, suggesting that polymorphism in chromosome length may itself be a major source of karyotypic variation. The genetic analysis of such variants indicated that recombinational events leading to new chromosomal forms may occur both mitotically and meiotically.

Aneuploidy↗
PubMed2003

Genome-wide amplifications caused by chromosomal rearrangements play a major role in the adaptive evolution of natural yeast.

The relative importance of gross chromosomal rearrangements to adaptive evolution has not been precisely defined. The Saccharomyces cerevisiae flor yeast strains offer significant advantages for the study of molecular evolution since they have recently evolved to a high degree of specialization in a very restrictive environment. Using DNA microarray technology, we have compared the genomes of two prominent variants of S. cerevisiae flor yeast strains. The strains differ from one another in the DNA copy number of 116 genomic regions that comprise 38% of the genome. In most cases, these regions are amplicons flanked by repeated sequences or other recombination hotspots previously described as regions where double-strand breaks occur. The presence of genes that confer specific characteristics to the flor yeast within the amplicons supports the role of chromosomal rearrangements as a major mechanism of adaptive evolution in S. cerevisiae. We propose that nonallelic interactions are enhanced by ethanol- and acetaldehyde-induced double-strand breaks in the chromosomal DNA, which are repaired by pathways that yield gross chromosomal rearrangements. This mechanism of chromosomal evolution could also account for the sexual isolation shown among the flor yeast.

Alleles↗