Modeling risk for developing drug resistant bacterial infections in an MDR-naive critically ill population

Tracking Epidemiological Characteristics and Risk Factors of Multi-Drug Resistant Bacteria in Intensive Care Units

Objectives

Multi-drug resistance (MDR) emerged as a serious threat in intensive care unit (ICU) settings. Our study aimed to investigate the major pathogens in ICU and identify the risk factors for MDR infection.

Methods

We performed a retrospective analysis of patients admitted to the ICU. Multivariate logistic regression was applied to identify the independent predictors, and then a nomogram to predict the probability of MDR infection.

Results

A total of 278 patients with 483 positive cultures were included. 249 (51.55%) had at least one MDR pathogen, including extensively drug-resistant (XDR) 77 (30.92%) and pan drug-resistant (PDR) 39 (15.66%), respectively. Klebsiella pneumonia was the most frequently isolated pathogen. We identified the number of bacteria (OR 2.91, 95% CI 1.97-4.29, P < 0.001), multiple invasive procedures (OR 2.23, 95% CI 1.37-3.63, P = 0.001), length of stay (LOS) (OR 1.01, 95% CI 1.00-1.02, P = 0.007), Hemoglobin (Hb) (OR 0.99, 95% CI 0.98-1.00, P = 0.01) were independent risk factors for MDR infection. Our nomogram displayed good discrimination with curve AUC was 0.75 (95% CI: 0.70-0.81). The decision curves also indicate the clinical utility of our nomogram. Additionally, the in-hospital mortality with MDR pathogens was independently associated with XDR (HR, 2.60; 95% CI: 1.08-6.25; P = 0.03) and total protein (TP) (HR, 0.95; 95% CI: 0.91-0.99; P = 0.03).

Conclusion

The number of bacteria, multiple invasive procedures, LOS, and Hb were the independent predictors associated with MDR pathogens. Our nomogram is potentially useful for predicting the occurrence of MDR infection. Besides, we also identify XDR and TP as the independent risk factors for in-hospital mortality with MDR infection. The current prevalence of MDR strains was also described. The results will contribute to the identification and preventive management of patients at increased risk of infection.

A Study of Multidrug-Resistant, Colistin-Only-Sensitive Infections in Intubated and Mechanically Ventilated Patients Over 2 Years

Background and Aims

Multidrug-resistant, Gram-negative infections are increasingly common in the intensive care unit (ICU). This study compares the occurrence and outcome of colistin-only-sensitive (COS) infections among mechanically ventilated patients at a tertiary hospital ICU.

Methods

The study included adult patients admitted over a period of 2 years, who were intubated and mechanically ventilated for more than 48 h. They were divided into two groups, those with COS infections and those without, and their GCS and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, ICU length of stay, leukocyte count, and mortality were compared. COS patients were divided into neurosurgery, neurology, respiratory, and sepsis with bacteremia groups. The COS organisms in each group, their sources, ICU length of stay, ventilator-free days, and mortality were analyzed.

Results

Three hundred and one patients were selected, of whom 41 (13.6%) had COS infections. COS patients had a longer ICU length of stay than non-COS patients (P = 0.001) but comparable APACHE II and GCS scores, leukocyte count, and mortality. The sepsis group accounted for 8 out of 15 (53%) deaths among COS patients (P = 0.03). Acinetobacter baumannii accounted for 61% of the COS infections, Klebsiella pneumonia: 24.4%, Pseudomonas aeruginosa: 12.2%, and Escherichia coli: 2.4%. Endotracheal secretion cultures accounted for 65.8% of COS isolates, urine cultures 17%, pus cultures 7.3%, and blood cultures 4.9%. ICU length of stay, ventilator-free days, and mortality were similar between each COS organism.

Conclusion

Intubated patients with multidrug-resistant, COS infections have a longer stay in ICU than non-COS patients. COS infections associated with bacteremia have high mortality.

Derivation and validation of a simple score to predict the presence of bacteria requiring carbapenem treatment in ICU-acquired bloodstream infection and pneumonia: CarbaSCORE

Background

The recommendations of learned societies mention risk factors for the presence of multidrug resistant bacteria in hospital-acquired infections, but they do not propose a scoring system to guide empiric antibiotic therapy. Our study was aimed at developing a simple score for predicting "the presence of bacteria requiring carbapenem treatment" in ICU-acquired bloodstream infection and pneumonia.

Methods

Between December 2011 and January 2015, we conducted a retrospective study using a prospectively collected French database of nosocomial infections in the polyvalent intensive care unit of a French university hospital. All patients with ICU-acquired bloodstream infection or pneumonia were included in the study. Bivariate and multivariate analyses were performed to develop the CarbaSCORE, and this score was internally validated.

Results

In total, 338 patients were analyzed, including 27 patients requiring carbapenem treatment. The CarbaSCORE was composed of four criteria: "presence of bloodstream infection" (as opposed to pneumonia) scored 2 points, "chronic hemodialysis" scored 4 points, "travel abroad in the last 6 months" scored 5 points, and "MDR-colonization or prior use of a β-lactam of class ≥ 3" scored 6 points. Internal validation by bootstrapping showed an area under the receiver operating characteristic curve of 0.81 [0.73-0.89]. Sensitivity was 96% at the 6-point threshold and specificity was 91% at the 9-point threshold.

Conclusions

The CarbaSCORE is a simple and efficient score for predicting the presence of bacteria requiring carbapenem treatment. Further studies are needed to test this score before it can be used in practice.