this is just a disgrace....at this hospital, e coli is more resistant to cipro when compared to Ancef....and now, in the last 6 weeks, all the zosyn sensitivities are coming back with a MIC of <16 (this is due to the MDs writing for zosyn like its free candy)
does anyone have any ideas how we can address this? 2 of our big guns are becoming more vulnerable, and its really scary
When you make this statement, I am uncertain you fully understand exactly what you are trying to say (if that makes sense). First, you may be confusing the concepts of susceptibility breakpoints with minimum inhibitory concentrations. If the MIC of piperacillin/tazobactam was <16 mcg/mL for a Pseudomonas isolate, this would be a good thing, and indicate the bacteria was sensitive to the medication. When you comment on all of the "sensitivities are coming back with a MIC of <16," the information really means nothing unless you give us a corresponding pathogen.
There has been controversy over the past couple years regarding the appropriateness of the CLSI breakpoint for piperacillin/tazobactam against, in particular, Pseudomonas isolates. Some clinicians feel a susceptibility breakpoint of 64 mcg/mL (which it officially is/was) is too high, and a group of pharmacists from Houston published a paper suggesting a higher rate of mortality in bacteremic patients who's Pseudomonas isolate had an MIC of 32 or 64 (retrospective analysis, compared to the patients with Pseudomonas blood stream isolates with MIC's of <32 mcg/mL).
This paper was published in CID, and caused some to believe this may lead to an official revision of the breakpoints by the CLSI (which is rare, but the last two revisions were recent and notable, for vancomycin and ceftriaxone). Your hospital's microbiology director may have decided, based on the available evidence, to revise the breakpoints him/herself, in an effort to prevent the prescribing of piperacillin/tazobactam when there may indeed be reduced susceptibility. So in reality, to answer your question regarding how to address the overprescribing of a broad spectrum agent, revising the breakpoints to make therapeutic expectations more "reasonable" (ie, if the MIC is >16, piperacillin/tazobactam will no longer be listed as "sensitive") will actually help with the issue, and may be in the best interest of the patients with Pseudomonal bacteremia.
