Recent Research

Hand hygiene, the July effect, migraines and stroke, and more.

Hand hygiene, chlorhexidine baths may be enough to prevent MRSA

When hand hygiene and unit-wide chlorhexidine bathing are performed faithfully in ICUs, universal screening and isolation measures may not be necessary to reduce acquisition of methicillin-resistant Staphylococcus aureus (MRSA), a recent study suggests.

Researchers sought to test the effect of rapid screening and isolation of carriers on colonization of resistant bacteria in settings where best standard precautions were already in place. First, they conducted a 6-month baseline assessment of 13 European ICUs. In phase 2, they performed an interrupted time-series study of universal chlorhexidine bathing coupled with hand hygiene improvement for an additional 6 months.

For phase 3, the researchers randomly assigned the ICUs to conventional screening (chromogenic screening for MRSA and vancomycin-resistant enterococci [VRE]) or rapid screening (polymerase chain reaction testing for MRSA and VRE and chromogenic screening for highly resistant Enterobacteriaceae [HRE]). In addition, they took contact precautions with identified carriers. The main study outcome was acquisition of antimicrobial-resistant bacteria per 100 patient-days at risk. Results were published in the January 2014 Lancet Infectious Diseases.

The entire study period was between May 2008 and April 2011. A total of 64,997 swabs were analyzed. Mean hand hygiene compliance improved from 52% at baseline to 69% in phase 2 and 77% in phase 3. The median proportion of patients who got chlorhexidine bathing increased from 0% at baseline to 100% in phase 2. Acquisition of resistant bacteria decreased significantly after implementation of phase 2 (weekly incidence rate ratio [IRR], 1.014 in phase 1 to 0.976 in phase 2; P=0.04). The decline appeared to be driven mostly by lowering MRSA acquisition (IRR, 1.042 to 0.925; P<0.001), as there was no significant reduction in VRE or HRE acquisition. In phase 3, there was no further reduction in acquisition of any individual or composite bacteria, and acquisition didn't differ significantly between the conventional screening group and the rapid screening group.

When there was a sustained high level of compliance to hand hygiene and chlorhexidine baths, acquisition rates of resistant bacteria weren't improved by screening and isolation of carriers, the authors wrote. MRSA was especially susceptible to hand hygiene and chlorhexidine baths, they noted. These findings are consistent with recent studies, they added, but may not apply to settings with lower hand hygiene compliance. The fact that no intervention had an effect on HRE acquisition suggests new methods may be needed to control these bacteria, such as selective digestive decontamination, they wrote.

July effect seen for high-risk heart attack patients

High-risk heart attack patients have similar death rates in teaching-intensive and non-teaching-intensive hospitals in July but lower death rates in teaching hospitals in May, a study found.

Researchers used the U.S. Nationwide Inpatient Sample to examine data from 98 teaching-intensive and 1,353 non-teaching-intensive hospitals during May and July 2002 to 2008. They looked at rates of all-cause inpatient mortality, percutaneous coronary intervention (PCI), and bleeding complications in high- and low-risk patients with acute myocardial infarction (AMI). High-risk patients were defined as those in the top quartile of predicted AMI mortality, and teaching-intensive hospitals were defined as those with more than 0.60 resident physician per bed. Results were published in the Dec. 24, 2013 Circulation.

There were 61,298 patients from non-teaching-intensive hospitals and 14,919 from teaching-intensive hospitals. Adjusted mortality for high-risk patients was 18.8% in May versus 22.7% in July in teaching-intensive hospitals (P<0.01); for non-teaching-intensive hospitals, rates were 22.5% in May versus 22.8% in July (P=0.70). Mortality rates for lower-risk patients were similar in May and July in both kinds of hospitals. There were no significant differences between patients or hospital types in PCI and bleeding complication rates, thus these factors could not explain the differences in mortality rates, the authors noted.

The results are “consistent with an adverse impact of organizational disruption and physician inexperience in teaching-intensive hospitals in July on outcomes of high risk AMI patients,” the authors concluded. They added that this is the first study to evaluate how the July effect may vary by severity of patient illness. “[Previous] studies [did] not examine patient populations whose mortality outcomes are most likely to be adversely impacted by the relative inexperience of residents in July,” they noted.

Migraineurs may have more risk of hemorrhagic stroke

People with migraine may have an increased risk of hemorrhagic stroke, especially women younger than 45, a meta-analysis found.

Researchers reviewed the literature through March 2013 for case-control and cohort studies with a clear definition of the diagnostic criteria for migraine and hemorrhagic stroke to find 8 studies (4 case-control and 4 cohort studies) involving a total of 1,600 hemorrhagic strokes.

Results appeared in the November 2013 Stroke.

The overall pooled adjusted effect estimate of hemorrhagic stroke in subjects with any migraine versus control subjects was 1.48 (95% CI, 1.16 to 1.88; P=0.002), with moderate statistical heterogeneity (I2=54.7%; P value for Q test=0.031). The increase in hemorrhagic stroke associated with migraine with aura (1.62; 95% CI, 0.87 to 3.03; P=0.129) was not significant.

Compared with control subjects, the risk of hemorrhagic stroke was greater in women with any migraine (1.55; 95% CI, 1.16 to 2.07; P=0.003), as well as female migraineurs under 45 years old (1.57; 95% CI, 1.10 to 2.24; P=0.012).

Researchers noted that only 2 studies reported data for men, so a direct comparison of the risk in women with the risk in men was not possible. The analysis could not determine the effects of migraines with or without aura because only 2 cohort studies and 1 case- control study collected data on the risk of hemorrhagic stroke according to migraine type. The group of patients who had migraines with aura was a smaller subgroup and the effect size estimate was higher than that for migraine without aura, so the meta-analysis may not have sufficient power to detect an association, the study authors noted. Also, an analysis based on only 8 studies may limit the conclusiveness of the results. Finally, the mechanisms underlying the association between migraine and hemorrhagic stroke are uncertain.

“Consequently, no alert should be given to migraineurs because no changes to their current standard treatments are needed,” the authors wrote. “Indeed, to date, the best recommendation for physicians treating subjects with migraine is to continue to focus carefully on those factors that could increase their risk of vascular events.”

Antibiotics may not benefit patients with catheters, bacteriuria

Bacteriuria infrequently leads to bacteremia in hospitalized patients, and antibiotic treatment of bacteriuria doesn't seem to affect mortality outcomes, a recent study found.

Researchers performed a retrospective cohort study at a large tertiary care facility in Texas between October 2010 and June 2011. Subjects were 308 inpatients with a urinary external or indwelling catheter and a positive urine culture. Researchers looked at outcomes 30 days after the positive culture. Results were in the November 2013 Infection Control and Hospital Epidemiology.

There were 444 episodes of catheter-associated bacteriuria. One hundred twenty-eight patients (41.6%) had catheter-associated urinary tract infections (CAUTIs) and 180 (58.4%) had catheter-associated asymptomatic bacteriuria (CAABU). There were 3 episodes of bacteriuria followed by bacteremia from a urinary source (0.7%).

In total, 52 cases of bacteremia were found in the patients, 32 (61.5%) in patients who had CAUTI and 20 (38.5%) in those who had CAABU. CAUTI was significantly associated with bacteremia from any source (odds ratio [OR], 2.8), while having an external catheter rather than an indwelling catheter had a protective effect (OR, 0.5). Variables significantly associated with mortality included a higher Charlson comorbidity score (OR, 1.1) and having a pure growth of Candida versus a gram-negative rod organism in the urine culture (OR, 3.6).

Use of antimicrobial agents to treat bacteriuria wasn't associated with a significant reduction in bacteremia or mortality within 30 days. The researchers noted that they were unable to analyze whether withholding antimicrobials entirely would have affected the incidence of bacteremia from any source because all 52 episodes of bacteremia were associated with prescription of at least 1 antimicrobial agent within 7 days before to 30 days after the original positive urine culture.

The study population had a mortality rate of 21.1%, comparable to other studies, and patients had an average comorbidity score of 4.1, which was associated with mortality, the authors wrote. Also, the associated mortality of Candida versus a gram-negative organism has been found in other studies and likely reflects heavy prior antimicrobial use in patients with substantial underlying comorbidities.

Statins didn't improve survival for VAP patients in the ICU

Adjunctive simvastatin therapy didn't improve survival for ICU patients with suspected ventilator-associated pneumonia (VAP), a study found.

In a randomized, controlled trial in 26 French ICUs, researchers enrolled patients with suspected VAP who had received invasive mechanical ventilation for at least 2 days. Suspected VAP was defined by a modified Clinical Pulmonary Infection Score of 5 or higher. Patients were randomized to receive 60 mg of simvastatin or placebo, starting on the same day they started antibiotics and continuing until death, day 28 or ICU discharge. The main outcome was 28-day mortality. Results were published in the Oct. 23/30, 2013, Journal of the American Medical Association.

The predefined futility stopping rule was an absolute increase of at least 2.7% in 28-day mortality with simvastatin versus placebo after enrollment of the first 251 patients. As such, the study was stopped for futility at the first scheduled interim analysis, with 300 patients enrolled. Mortality at 28 days for those patients was 21.2% in the simvastatin group and 15.2% in the placebo group (P=0.10; hazard ratio, 1.45). In statin-naive patients, 28-day mortality was 21.5% with simvastatin and 13.8% with placebo (P=0.054).

There were no significant differences between groups in secondary outcomes, such as death at 14 days, death in the ICU or hospital, duration of mechanical ventilation or changes in sequential organ failure assessment (SOFA) score.

Statins don't seem to improve survival outcomes of patients with suspected VAP, the authors wrote, and this conclusion “probably deserves to be extended to ICU patients with any type of nosocomial infection.” The results may have limited relevance for non-ICU-acquired infections, however, they wrote.