Restriction fragment length polymorphisms analysis by pulsed-field gel electrophoresis for discrimination of Staphylococcus aureus isolates from foodborne outbreaks

1999 ◽  
Vol 46 (3) ◽  
pp. 271-274 ◽  
Author(s):  
Y Suzuki
2000 ◽  
Vol 38 (4) ◽  
pp. 1575-1580 ◽  
Author(s):  
Vicki A. Luna ◽  
Daniel B. Jernigan ◽  
Alan Tice ◽  
James D. Kellner ◽  
Marilyn C. Roberts

In 1997, a cluster of multiresistant invasive serogroup 19 pneumococcus infections, including two fatalities, was reported in Washington State. Further investigation identified other cases. Fourteen Washington Streptococcus pneumoniae isolates, four from Alaska, and eight isolates from eastern Canada with reduced penicillin susceptibility (MIC of ≥1 μg/ml) were included in the study. Pulsed-field gel electrophoresis (PFGE) with ApaI,SacII, and SmaI restriction enzymes and IS1167 and mef restriction fragment length polymorphism (RFLP) pattern analysis were performed. Twenty of the 26 isolates had identical or related PFGE patterns, with two or all three enzymes, and identical or related IS1167 RFLP patterns, indicating that they were genetically related. These 20 isolates contained the mef gene conferring erythromycin resistance and had identical mef RFLP patterns. The PFGE and RFLP patterns were distinct from those of six multiresistant clones previously described and suggest that a new multiresistant clone has appeared in Washington, Alaska, and eastern Canada. This newly characterized clone should be included in the Pneumococcal Molecular Epidemiology Network.


1995 ◽  
Vol 66 (2) ◽  
pp. 109-126 ◽  
Author(s):  
Jinrui Shi ◽  
David G. Heckel ◽  
Marian R. Goldsmith

SummaryWe present data for the initial construction of a molecular linkage map for the domesticated silkworm, Bombyx mori, based on 52 progeny from an F2 cross from a pair mating of inbred strains p50 and C108, using restriction fragment length polymorphisms (RFLPs). The map contains 15 characterized single copy sequences, 36 anonymous sequences derived from a follicular cDNA library, and 10 loci corresponding to a low copy number retrotransposon, mag. The 15 linkage groups and 8 ungrouped loci account for 23 of the 28 chromosomes and span a total recombination length of 413 cM; 10 linkage groups were correlated with established classic genetic maps. Scoring data from Southern blots were analysed using two Pascal programs written specifically to analyse linkage data in Lepidoptera, where females are the heterogametic sex and have achiasmatic meiosis (no crossing-over). These first examine evidence for linkage by calculating the maximum lod score under the hypothesis that the two loci are linked over the likelihood under the hypothesis that the two loci assort independently, and then determine multilocus linkage maps for groups of putatively syntenic loci by calculating the maximum likelihood estimate of the recombination fractions and the log likelihood using the EM algorithm for a specified order of loci along the chromosome. In addition, the possibility of spurious linkage was exhaustively tested by searching for genotypes forbidden by the absence of crossing-over in one sex.


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