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Research describes the development of a real-time polymerase chain reaction assay based on 5' nuclease system to detect specific C sequence in Campylobacter jejuni. The assay shows linearity of quantification of food contamination over six orders of magnitude, detecting up to 12 genome equivalents. The new assay takes 3 h and applicable to a diverse range of Campylobacter species and other related and unrelated genera.

Intrinsic antimicrobial resistance of Escherichia coli is elicited by the gene products of the multidrug efflux acrAB-tolC operon. In this paper, we have shown that acrAB is regulated as a function of the growth rate of E. coli during growth in batch and chemostat culture. In chemostat culture, expression of acrAB is inversely related to growth rate irrespective of the limiting nutrient. The level of expression of acrAB is greater under glucose limitation compared with either iron or nitrogen limitation. Increase in expression of acrAB confers a greater resistance to ciprofloxacin, and the implications for a clinical situation are discussed. Slow growth rate regulation of acrAB transcription does not require the presence of the stationary-phase sigma factor. A putative gearbox consensus sequence was identified at the −10 region of the acrAB promoter. [Copyright &y& Elsevier]