Thoughts On A Completely Drug Resistant Klebsiella

Since I’ve been asked about this, I’ll have some comments in a bit, but first, the CDC report (boldface mine):

On August 25, 2016, the Washoe County Health District in Reno, Nevada, was notified of a patient at an acute care hospital with carbapenem-resistant Enterobacteriaceae (CRE) that was resistant to all available antimicrobial drugs. The specific CRE, Klebsiella pneumoniae, was isolated from a wound specimen collected on August 19, 2016. After CRE was identified, the patient was placed in a single room under contact precautions. The patient had a history of recent hospitalization outside the United States. Therefore, based on CDC guidance (1), the isolate was sent to CDC for testing to determine the mechanism of antimicrobial resistance, which confirmed the presence of New Delhi metallo-beta-lactamase (NDM)

Antimicrobial susceptibility testing in the United States indicated that the isolate was resistant to 26 antibiotics, including all aminoglycosides and polymyxins tested, and intermediately resistant to tigecycline (a tetracycline derivative developed in response to emerging antibiotic resistance). Because of a high minimum inhibitory concentration (MIC) to colistin, the isolate was tested at CDC for the mcr-1 gene, which confers plasma-mediated resistance to colistin; the results were negative. The isolate had a relatively low fosfomycin MIC of 16 μg/mL by ETEST. However, fosfomycin is approved in the United States only as an oral treatment of uncomplicated cystitis; an intravenous formulation is available in other countries.

Three things to note. The first is the role exposure to other countries’ medical system played. The NDM-1 carbapenemase (which confers resistance to all drugs ending in -enem and -cillin as well as the cephalosporins, or ‘ceph, cef-‘ and so on) is very rare in the U.S.; the usual U.S. suspects are KPC, VIM, and OXA.

Second, aminoglycosides (amikacin, gentamicin, streptomycin, tobramycin) are really important. Many carbapenem resistant organisms possess multiple aminoglycoside resistance genes, though usually amikacin is effective. These aren’t ‘sexy’ drugs (most are off patent), but they are important–and effective:

…although CRE are commonly sent to CDC as part of surveillance programs or for reference testing, isolates that are resistant to all antimicrobials are very uncommon. Among >250 CRE isolate reports collected as part of the Emerging Infections Program, approximately 80% remained susceptible to at least one aminoglycoside and nearly 90% were susceptible to tigecycline.

Regarding CREs and agriculture, aminoglycosides, in particular gentamicin, are where I think agricultural use of antibiotics contributes to the problem.

Third, this case highlights the importance of transferable medical information. I can’t tell you how many anecdotes I’ve heard from infectious disease specialists who have to treat these cases, who tell how the previous facility knew the patient had a CRE and did not pass that information along. That needs to stop.

The ‘good’ news is that NDM-1 carrying organisms don’t seem to have established in the U.S., though it’s probably just a matter of time.

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One Response to Thoughts On A Completely Drug Resistant Klebsiella

  1. afeman says:

    Huh? Kielbasa? Oooh.

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