From the Journals

Predicting MDR Gram-negative infection mortality risk



Source control, defined as location and elimination of the source of the infection, was critical for patient survival in the case of multidrug resistant bacterial infection, according to the results of a case-control study of 62 critically ill surgical patients who were assessed between 2011 and 2014.

Researchers examined the characteristics of infected patients surviving to hospital discharge compared with those of nonsurvivors to look for predictive factors. Demographically, patients had an overall mean age of 62 years; 30.6% were women; 69.4% were white. The first culture obtained during a surgical ICU admission that grew a carbapenem-resistant Enterobacteriaceae (CRE), MDR Pseudomonas aeruginosa, or MDR Acinetobacter spp. was defined as the index culture.

“In this study, 33.9% [21/62] of critically ill surgical patients with a culture positive for MDR Gram-negative bacteria died prior to hospital discharge,” according to Andrew S. Jarrell, PharmD, of the Johns Hopkins Hospital, Baltimore, and his colleagues.

With multivariate logistic regression, achievement of source control was the only variable associated with decreased in-hospital mortality (odds ratio 0.04, 95% confidence interval, 0.003-0.52); P = .01).

“Source control status was predictive of in-hospital mortality after controlling for other factors. Specifically, the odds of in-hospital mortality were 97% lower when source control was achieved as compared to when source control was not achieved,” the authors stated (J Crit Care. 2018;43:321-6).

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They suggested that the importance of source control in these surgical patients may be related to the limitations of antibiotics in treating MDR organisms, making a successful procedural intervention on the infectious source important for patient survival. Comparing survivors and nonsurvivors, definitive antibiotic therapy was largely similar.

Scenarios in which source control was not applicable (pneumonia and urinary tract infection) were also similarly distributed between survivors and nonsurvivors, they reported.

Other than source control, the only significant risk factors for mortality, as seen in univariate analysis, all occurred prior to index culture. They were: vasopressor use (46.3% of survivors, vs. 76.2% of nonsurvivors, P = .03); mechanical ventilation (63.4% vs. 100%, P = .001); and median ICU length of stay (10 days vs. 18 days, P = .001).

“Achievement of source control stands out as a critical factor for patient survival. Clinicians should take this, along with prior ICU LOS, vasopressor use, and mechanical ventilation status, into consideration when evaluating patient prognosis,” Dr. Jarrell and his colleagues concluded.

The authors reported that they had no conflicts or source of funding.

Source: Jarrell, A.S., et al. J Crit Care. 2018;43:321-6.

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