Antibiotic resistance is a major threat to public health. Resistance is largely driven by antibiotic usage, which in many cases is unnecessary and can be improved. The impact of decreasing overall antibiotic usage on resistance is unknown and difficult to assess using standard study designs. The objective of this study was to explore the potential impact of reducing antibiotic usage on the transmission of multidrug-resistant organisms (MDROs).

We used agent-based modeling to simulate interactions between patients and healthcare workers (HCWs) using model inputs informed by the literature. We modeled the effect of antibiotic usage as (1) a microbiome effect, for which antibiotic usage decreases competing bacteria and increases the MDRO transmission probability between patients and HCWs and (2) a mutation effect that designates a proportion of patients who receive antibiotics to subsequently develop a MDRO via genetic mutation.

Intensive care unit

Absolute reduction in overall antibiotic usage by experimental values of 10% and 25%

Reducing antibiotic usage absolutely by 10% (from 75% to 65%) and 25% (from 75% to 50%) reduced acquisition rates of high-prevalence MDROs by 11.2% (P<.001) and 28.3% (P<.001), respectively. We observed similar effect sizes for low-prevalence MDROs.

In a critical care setting, where up to 50% of antibiotic courses may be inappropriate, even a moderate reduction in antibiotic usage can reduce MDRO transmission.

Infect Control Hosp Epidemiol 2017;38:663–669

Measuring processes of care performance rates is an invaluable tool for quality improvement; however, collecting daily process measure data is time-consuming and burdensome.

To evaluate the accuracy of sampling strategies to estimate monthly compliance rates with ventilator-associated pneumonia prevention measures.

A total of 37 intensive care units affiliated with 29 hospitals participating in a 2-state 35-month ventilator-associated pneumonia prevention collaborative. Analysis was limited to 325 unit-months with complete data entry rates.

We calculated unit-month level actual and sample monthly compliance rates for 6 ventilator-associated pneumonia prevention measures, using 4 sampling strategies: sample 1 day per month, sample 1 day per week, sample 7 consecutive days per month, and sample 7 consecutive days per month plus additional consecutive days as necessary to obtain at least 30 ventilator-days for that month whenever possible. We compared sample versus actual rates using paired t test and χ2 test.

Mean sampling accuracy ranged 84%–97% for 1 day per month, 91%–98% for 1 day per week, 92%–98% for 7 consecutive days per month, and 96%–99% for 7 consecutive days with at least 30 days per month if possible. The most accurate sampling strategy was to sample 7 consecutive days with at least 30 ventilator-days per month if possible. With this strategy, sample rates were within 10% of actual rates in 88%–99% of unit-months and within 5% of actual rates in 74%–97% of unit-months.

Sampling process measures intermittently rather than continually can yield accurate estimates of process measure performance rates.

Infect Control Hosp Epidemiol 2016;37:1037–1043

Diagnosing ventilator-associated pneumonia (VAP) is difficult, and misdiagnosis can lead to unnecessary and prolonged antibiotic treatment. We sought to quantify and characterize unjustified antimicrobial use for VAP and identify risk factors for continuation of antibiotics in patients without VAP after 3 days.

Patients suspected of having VAP were identified in 6 adult intensive care units (ICUs) over 1 year. A multidisciplinary adjudication committee determined whether the ICU team's VAP diagnosis and therapy were justified, using clinical, microbiologic, and radiographic data at diagnosis and on day 3. Outcomes included the proportion of VAP events misdiagnosed as and treated for VAP on days 1 and 3 and risk factors for the continuation of antibiotics in patients without VAP after day 3.

Two hundred thirty-one events were identified as possible VAP by the ICUs. On day 1, 135 (58.4%) of them were determined to not have VAP by the committee. Antibiotics were continued for 120 (76%) of 158 events without VAP on day 3. After adjusting for acute physiology and chronic health evaluation II score and requiring vasopressors on day 1, sputum culture collection on day 3 was significantly associated with antibiotic continuation in patients without VAP. Patients without VAP or other infection received 1,183 excess days of antibiotics during the study.

Overdiagnosis and treatment of VAP was common in this study and led to 1,183 excess days of antibiotics in patients with no indication for antibiotics. Clinical differences between non-VAP patients who had antibiotics continued or discontinued were minimal, suggesting that clinician preferences and behaviors contribute to unnecessary prescribing.

Several studies demonstrating that central line–associated bloodstream infections (CLABSIs) are preventable prompted a national initiative to reduce the incidence of these infections.

We conducted a collaborative cohort study to evaluate the impact of the national “On the CUSP: Stop BSI” program on CLABSI rates among participating adult intensive care units (ICUs). The program goal was to achieve a unit-level mean CLABSI rate of less than 1 case per 1,000 catheter-days using standardized definitions from the National Healthcare Safety Network. Multilevel Poisson regression modeling compared infection rates before, during, and up to 18 months after the intervention was implemented.

A total of 1,071 ICUs from 44 states, the District of Columbia, and Puerto Rico, reporting 27,153 ICU-months and 4,454,324 catheter-days of data, were included in the analysis. The overall mean CLABSI rate significantly decreased from 1.96 cases per 1,000 catheter-days at baseline to 1.15 at 16–18 months after implementation. CLABSI rates decreased during all observation periods compared with baseline, with adjusted incidence rate ratios steadily decreasing to 0.57 (95% confidence intervals, 0.50–0.65) at 16–18 months after implementation.

Coincident with the implementation of the national “On the CUSP: Stop BSI” program was a significant and sustained decrease in CLABSIs among a large and diverse cohort of ICUs, demonstrating an overall 43% decrease and suggesting the majority of ICUs in the United States can achieve additional reductions in CLABSI rates.

To evaluate the impact of a multifaceted intervention on compliance with evidence-based therapies and ventilator-associated pneumonia (VAP) rates.

Collaborative cohort before-after study.

Intensive care units (ICUs) predominantly in Michigan.

We implemented a multifaceted intervention to improve compliance with 5 evidence-based recommendations for mechanically ventilated patients and to prevent VAP. A standardized CDC definition of VAP was used and maintained at each site, and data on the number of VAPs and ventilator-days were obtained from the hospital's infection preventionists. Baseline data were reported and postimplementation data were reported for 30 months. VAP rates (in cases per 1,000 ventilator-days) were calculated as the proportion of ventilator-days per quarter in which patients received all 5 therapies in the ventilator care bundle. Two interventions to improve safety culture and communication were implemented first.

One hundred twelve ICUs reporting 3,228 ICU-months and 550,800 ventilator-days were included. The overall median VAP rate decreased from 5.5 cases (mean, 6.9 cases) per 1,000 ventilator-days at baseline to 0 cases (mean, 3.4 cases) at 16–18 months after implementation (P < .001) and 0 cases (mean, 2.4 cases) at 28-30 months after implementation (P < .001). Compared to baseline, VAP rates decreased during all observation periods, with incidence rate ratios of 0.51 (95% confidence interval, 0.41–0.64) at 16–18 months after implementation and 0.29 (95% confidence interval, 0.24–0.34) at 28–30 months after implementation. Compliance with evidence-based therapies increased from 32% at baseline to 75% at 16–18 months after implementation (P < .001) and 84% at 28–30 months after implementation (P < .001).

A multifaceted intervention was associated with an increased use of evidence-based therapies and a substantial (up to 71%) and sustained (up to 2.5 years) decrease in VAP rates.