Elsevier

Journal of Infection

Volume 70, Issue 3, March 2015, Pages 213-222
Journal of Infection

Resistance patterns and outcomes in intensive care unit (ICU)-acquired pneumonia. Validation of European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC) classification of multidrug resistant organisms

https://doi.org/10.1016/j.jinf.2014.10.004Get rights and content

Summary

Introduction

Bacterial resistance has become a major public health problem.

Objective

To validate the definition of multidrug-resistant organisms (MDRO) based on the European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC) classification.

Material

Prospective, observational study in six medical and surgical Intensive-Care-Units (ICU) of a University hospital.

Results

Three-hundred-and-forty-three patients with ICU-acquired pneumonia (ICUAP) were prospectively enrolled, 140 patients had no microbiological confirmation (41%), 82 patients (24%) developed ICUAP for non-MDRO, whereas 121 (35%) were MDROs. Non-MDRO, MDRO and no microbiological confirmation patients did not present either a significant different previous antibiotic use (p 0.18) or previous hospital admission (p 0.17). Appropriate antibiotic therapy was associated with better ICU survival (105 [92.9%] vs. 74 [82.2%]; p = 0.03). An adjusted multivariate regression logistic analysis identified that only MDRO had a higher ICU-mortality than non-MDRO and no microbiological confirmation patients (OR 2.89; p < 0.05; 95% CI for Exp [β]. 1.02–8.21); Patients with MDRO ICUAP remained in ICU for a longer period than MDRO and no microbiological confirmation respectively (p < 0.01) however no microbiological confirmation patients had more often antibiotic consumption than culture positive ones.

Conclusions

Patients who developed ICUAP due to MDRO showed a higher ICU-mortality than non-MDRO ones and use of ICU resources. No microbiological confirmation patients had more often antibiotic consumption than culture positive patients. Risk factors for MDRO may be important for the selection of initial antimicrobial therapy, in addition to local epidemiology.

Introduction

Bacterial resistance has become a major public health problem.1 In recent years, there have been frequent publications regarding resistant bacteria, while there has been no increase in the development of new antibiotics.2, 3 Current antibiotics are worldwide less effective due to the expression of various resistance mechanisms, which are having a major clinical, epidemiological and microbiologically impact.4 Multidrug-resistant organisms (MDRO) are labeled as such because of resistance to more than one antimicrobial agent. Some authors have referred to those bacteria that are potentially resistant and that may acquire a variety of mechanisms of resistance to multiple antibiotics.5, 6 In addition, the European Centre for Disease Prevention and Control (ECDC) and the Centers for Disease Control and Prevention (CDC) ECDC/CDC panel created a standardized international terminology with which to describe acquired resistance profiles of MDRO: Single multidrug-resistant (MDRs), extensively drug-resistant (XDR) and pandrug-resistant organisms (PDR).7 Although widespread, this classification lacks validation in clinical practice. In this study, we aimed to determine whether patients with MDRO manifested a worse clinical outcome and whether substantial differences existed when comparing different acquired resistance profiles with those with Intensive-Care-Unit acquired pneumonia (ICUAP).

Section snippets

Study population

The study was conducted in 6 specialized ICUs in an 800-bed university hospital. The investigators conducted daily rounds in the different ICUs. Patients aged over 18 years who had been admitted to these ICUs for at least 48 h with clinical suspicion of ICUAP were prospectively and consecutively included in the study. The ethics committee of the hospital approved the study (IRB Committee name: Hospital Clinic Barcelona/Project approval number IRB 3009/5453) and written informed consent was

Results

343 patients with ICUAP were prospectively enrolled (Fig. 1), 140 patients had no microbiological confirmation (41%), 82 patients (24%) developed ICUAP with non-MDRO pathogens, whereas 121 (35%) with MDRO. Mean age was 63.1 ± 14.5 years, 236 (68.8%) patients were male, and SAPS II score on admission was 39.1 ± 12.8 points for the patients included in the analysis.

Of the 203 patients with definite microbiology confirmation, 82 patients (40.4%) developed ICUAP with non-MDRO, whereas 121 (59.6%)

Discussion

In the current study, we validated a new classification of MDRO, including those with no microbiological confirmation based on the ECDC and CDC classification in a population of ICUAP. This study has two important findings: first, the high prevalence of MDRO observed in our study population carrying a higher mortality than non-resistant pathogens, even when patients with no microbiological confirmation were included in the analysis; and second the increased use of health care resources

Conclusions

In summary, based on our data, only patients with MDRO had a higher ICU-mortality than non-MDRO and no microbiological confirmation and a significantly higher ICU resources use, as defined by fewer MV free days and shorter ICU length of stay than patients with MDRO however no microbiological confirmation patients had more often antibiotic consumption than culture positive ones. Risk factors for MDRO may be important for the selection of initial antimicrobial therapy, in addition to local

Authors' contributions

IM-L & AT assisted in the design of the study coordinated patient recruitment, analyzed and interpreted the data and assisted in writing the paper. MR, ST, FdR, LF & GLB made important contributions to the acquisition and analysis of data. IML, PR, ED & GLB were involved in revising the manuscript critically for important intellectual content. IM-L, MF & AT made substantial contributions to the conception, design, analysis and interpretation of data and revised the final manuscript version. All

Conflict of interest

The authors have no conflict of interest to disclose.

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