Naslov
Diagnostic intricacies and fortuitous treatment approaches for carbapenemresistant Klebsiella pneumoniae

Autori
Meštrović, Tomislav ; Bedenić, Branka

Izvornik
Interactive Cardiovascular and Thoracic Surgery (1569-9293) 23 (2016), 5; 768-768

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, komentar, znanstveni

Ključne riječi
Klebsiella pneumoniae, carbapenem resistance, therapy

Sažetak
We read with great interest the article by Salsano et al. on the risk factors for carbapenemresistant Klebsiella pneumoniae (CRKp) infections following open heart surgery. Rapid dissemination of CRKp and other carbapenemase producing Gramn egative bacteria inevitably confronts us with a panoply of controversial issues regarding the choice of detection methods and therapy in patients postoperatively. Therefore our aim was to emphasize the importance of meticulous laboratory workup and to broaden the discussion by highlighting recently emerged treatment options. In the methods section the authors state that the interpretative breakpoints for evaluating carbapenem resistance were based on the European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria, but it has to be emphasized that certain bacterial isolates that produce carbapenemases are categorised as susceptible by using these breakpoints and (as recommended by the EUCAST criteria) should be reported as tested. Therefore the presence or absence of a carbapenemase does not in itself influence the categorisation of susceptibility, and the EUCAST critera recommend further carbapenemase detection and characterization for public health and infection control purposes. Still, the authors do not state whether they confirmed the carbapenemase detection by one of the commonly employed phenotypic screening methods, since polymerase chain reaction (PCR) was used only for blood CRKp isolates in this paper. The modified Hodge test would be the screening method of choice (although it is not without its sensitivity and specificity issues), while there are also several inhibitor based tests in various formats that can be employed (such as the combination disk test or imipenem (IPM)/imipenemEDTA Etest strips). Considering a very high rate of CRKp infections among colonized patients in this study (almost 50%) and the ensuing lifethreatening infectious events, it would be interesting to additionally investigate clonal relatedness of these bacterial isolates by using multilocus sequence typing (MLST) and pulsedfield gel electrophoresis (PFGE) analysis. The allelic variants that can be determined this way would help to understand the clonal relationship of CRKp strains, which is a pivotal step in epidemiological investigation and subsequent control of hospitalonset CRKp infections.Treatment of patients infected with CRKp is always troublesome due to multidrug (and sometimes even pandrug)resistance phenotype, thus the authors rightly state that two or three antimicrobials are often used concomitantly in order to increase the probability of adequate coverage and to take advantage of synergistic effects. One of such promising approaches is a combined therapy in which, rather surprisingly, one of the drugs is always a carbapenem (most appropriately meropenem) administered at high doses with an extended infusion to boost its pharmacokinetic and pharmacodynamic features.Even a more counterintuitive (albeit clinically auspicious) approach is a doublecarbapenem therapy that was effective in a dozen of patients with CRKp [4]. This type of treatment also shows promise in patients after heart surgery, as it resulted in a complete recovery of a patient from Italy who underwent aortic prosthesis replacement. It is hypothesized that one of the carbapenem compounds can distract the carbapenemase enzyme by acting as a suicide inhibitor (akin to clavulanate in amoxicillinclavulanate combination), hence preserving and allowing the activity of the other carbapenem drug.

Izvorni jezik
Engleski

Znanstvena područja
Temeljne medicinske znanosti

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