Differentiation of metronidazole-sensitive and -resistant clinical isolates of Helicobacter pylori by immunoblotting with antisera to the RdxA protein.

Antimicrobial resistance in Helicobacter pylori is a serious and increasing problem, and the development of rapid, reliable methods for detecting resistance would greatly improve the selection of antibiotics used to treat gastric infection with this organism. We assessed whether detection of the RdxA protein could provide the basis for determining the susceptibility of H. pylori to metronidazole. In order to raise polyclonal antisera to RdxA, we cloned the rdxA gene from H. pylori strain 26695 into the commercial expression vector pMAL-c2, purified the resultant fusion protein by affinity chromatography, and used this recombinant RdxA preparation to immunize rabbits. We then used this specific anti-RdxA antibody to perform immunoblotting on whole bacterial cell lysates of 17 metronidazole-sensitive and 27 metronidazole-resistant clinical isolates of H. pylori. While a 24-kDa immunoreactive band corresponding to the RdxA protein was observed in all metronidazole-sensitive strains, this band was absent in 25 of 27 resistant isolates. Our results indicate that testing for the absence of the RdxA protein would identify the majority of clinical isolates that will respond poorly to metronidazole-containing eradication regimens and have implications for the development of assays capable of detecting metronidazole resistance in H. pylori.

The ethics of managed care financial incentives to limit care. Some thoughts for specialists.

This article supplies an introduction to the structure and purpose of managed care financial incentives, with particular attention to those affecting referrals to specialists. It then addresses some of the ethical problems attending such incentive schemes and discusses the characteristics that make some financial incentives preferable to others. An agenda for specialists such as plastic surgeons who are often on the "receiving end" of incentive schemes designed to limit the use of specialty care is outlined. This proposed agenda encourages specialists to participate actively in shaping incentive schemes in ways that help keep health care costs down without sacrificing patients' interests in obtaining necessary specialty care.