Little is known about racial and ethnic disparities in the occurrence of healthcare-associated infections (HAIs) in hospitalized patients.

To determine whether racial/ethnic disparities exist in the rate of occurrence of HAIs captured in the Medicare Patient Safety Monitoring System (MPSMS).

Chart-abstracted MPSMS data from randomly selected all-payer hospital discharges of adult patients (18 years old or above) between January 1, 2009, and December 31, 2011, for 3 common medical conditions: acute cardiovascular disease (composed of acute myocardial infarction and heart failure), pneumonia, and major surgery for 6 HAI measures (hospital-acquired antibiotic-associated Clostridium difficile, central line-associated bloodstream infections, postoperative pneumonia, catheter-associated urinary tract infections, hospital-acquired methicillin-resistant Staphylococcus aureus, and ventilator-associated pneumonia).

The study sample included 79,019 patients who had valid racial/ethnic information divided into 6 racial/ethnic groups—white non-Hispanic (n = 62,533), black non-Hispanic (n = 9,693), Hispanic (n = 4,681), Asian (n = 1,225), Native Hawaiian/Pacific Islander (n = 94), and other (n = 793)—who were at risk for at least 1 HAI. The occurrence rate for HAIs was 1.1% for non-Hispanic white patients, 1.3% for non-Hispanic black patients, 1.5% for Hispanic patients, 1.8% for Asian patients, 1.7% for Native Hawaiian/Pacific Islander patients, and 0.70% for other patients. Compared with white patients, the age/gender/comorbidity-adjusted odds ratios of occurrence of HAIs were 1.1 (95% confidence interval [CI], 0.99-1.23), 1.3 (95% CI, 1.15-1.53), 1.4 (95% CI, 1.07-1.75), and 0.7 (95% CI, 0.40-1.12) for black, Hispanic, Asian, and a combined group of Native Hawaiian/Pacific Islander and other patients, respectively.

Among patients hospitalized with acute cardiovascular disease, pneumonia, and major surgery, Asian and Hispanic patients had significantly higher rates of HAIs than white non-Hispanic patients.

Surgical site infection (SSI) surveillance represents a key method of nosocomial infection control programs worldwide. However, most SSI surveillance systems are considered to be poorly cost effective regarding human and economic resources required for data collection and patient follow up. This study aims to assess the efficacy of using hospital discharge databases (HDDs) as a routine surveillance system for detecting hip or knee arthroplasty–related infections (HKAIs).

A case-control study was conducted among patients hospitalized in the Centre region of France between 2008 and 2010. HKAI cases were extracted from the HDD with various algorithms based on the International Classification of Diseases, Tenth Revision, and procedure codes. The control subjects were patients with hip or knee arthroplasty (HKA) without infection selected at random from the HDD during the study period. The gold standard was medical chart review. Sensitivity (Se), specificity (Spe), positive predictive value (PPV), and negative predictive value (NPV) were calculated to evaluate the efficacy of the surveillance system.

Among 18,265 hospital stays for HKA, corresponding to 17,388 patients, medical reports were checked for 1,010 hospital stays (989 patients). We identified 530 cases in total (incidence rate, 1% [95% confidence interval (CI), 0.4%–1.6%), and 333 cases were detected by routine surveillance. As compared with 480 controls, Se was 98%, Spe was 71%, PPV was 63%, and NPV was 99%. Using a more specific case definition, based on a sample of 681 hospital stays, Se was 97%, Spe was 95%, PPV was 87%, and NPV was 98%.

This study demonstrates the potential of HDD as a tool for routine SSI surveillance after low-risk surgery, under conditions of having an appropriate algorithm for selecting infections.

Infect Control Hosp Epidemiol 2014;35(6):646–651

Coronary artery bypass graft (CABG) and primary arthroplasty surgical site infection (SSI) rates are declining slower than other healthcare-associated infection rates. We examined antimicrobial prophylaxis (AMP) regimens used for these operations and compared their spectrum of activity against reported SSI pathogens.

Pathogen distributions of CABG and hip/knee arthroplasty complex SSIs (deep and organ/space) reported to the National Healthcare Safety Network (NHSN) from 2006 through 2009 and AMP regimens (same procedures and time period) reported to the Surgical Care Improvement Project (SCIP) were analyzed. Regimens were categorized as standard (cefazolin or cefuroxime), β-lactam allergy (vancomycin or clindamycin with or without an aminoglycoside), and extended spectrum (vancomycin and/or an aminoglycoside with cefazolin or cefuroxime). AMP activity of each regimen was predicted on the basis of pathogen susceptibility reports and published spectra of antimicrobial activity.

There were 6,263 CABG and arthroplasty complex SSIs reported (680,489 procedures; 880 NHSN hospitals). Among 6,574 pathogens reported, methicillin-sensitive Staphylococcus aureus (23%), methicillin-resistant S. aureus (18%), coagulase-negative staphylococci (17%), and Enterococcus species (7%) were most common. AMP regimens for 2,435,703 CABG and arthroplasty procedures from 3,330 SCIP hospitals were analyzed. The proportion of pathogens predictably susceptible to standard (used in 75% of procedures), β-lactam (12%), and extended-spectrum (8%) regimens was 41%–45%, 47%–96%, and 81%—96%, respectively.

Standard AMP, used in three-quarters of CABG and primary arthroplasty procedures, has inadequate activity against more than half of SSI pathogens reported. Alternative strategies may be needed to prevent SSIs caused by pathogens resistant to standard AMP regimens.

Development of a numerical score to measure the microbial spectrum of antibiotic regimens (spectrum score) and method to identify antibiotic de-escalation events based on application of the score.

Web-based modified Delphi method.

Physician and pharmacist antimicrobial stewards practicing in the United States recruited through infectious diseases–focused listservs.

Three Delphi rounds investigated: organisms and antibiotics to include in the spectrum score, operationalization of rules for the score, and de-escalation measurement. A 4-point ordinal scale was used to score antibiotic susceptibility for organism-antibiotic domain pairs. Antibiotic regimen scores, which represented combined activity of antibiotics in a regimen across all organism domains, were used to compare antibiotic spectrum administered early (day 2) and later (day 4) in therapy. Changes in spectrum score were calculated and compared with Delphi participants’ judgments on de-escalation with 20 antibiotic regimen vignettes and with non-Delphi steward judgments on de-escalation of 300 pneumonia regimen vignettes. Method sensitivity and specificity to predict expert de-escalation status were calculated.

Twenty-four participants completed all Delphi rounds. Expert support for concepts utilized in metric development was identified. For vignettes presented in the Delphi, the sign of change in score correctly classified de-escalation in all vignettes except those involving substitution of oral antibiotics. The sensitivity and specificity of the method to identify de-escalation events as judged by non-Delphi stewards were 86.3% and 96.0%, respectively.

Identification of de-escalation events based on an algorithm that measures microbial spectrum of antibiotic regimens generally agreed with steward judgments of de-escalation status.

Infect Control Hosp Epidemiol 2014;35(9):1103-1113

To compare direct laboratory costs of different methods for perirectal screening for carbapenemase-producing Enterobacteriaceae (CPE) colonization.

Cost-benefit analysis.

A university hospital and affiliated long-term acute care hospital (LTACH).

Inpatients from the hospital or LTACH.

Perirectal samples were collected from inpatients at risk for exposure to CPE. In 2009, we compared the accuracy of the Centers for Disease Control and Prevention (CDC)-recommended CPE screening method with similar methods incorporating a chromogenic agar (CA). We then performed a cost projection analysis using 2012 screening results for the CA method, the CDC method, and a molecular assay with wholesale pricing based on the 2009 analysis. Comparisons of turnaround and personnel time were also performed.

A total of 185 (2.7%) of 6,860 samples were confirmed as CPE positive during 2012. We previously found that the CDC protocol had a lower sensitivity than the CA method and predicted that the CDC protocol would have missed 92 of the CPE-positive screening results, whereas the modified protocol using CA would have missed 26, assuming similar prevalence and performance. Turnaround time was 3 days using the CDC and CA-modified protocols compared with 1 day for molecular testing. The estimated annual total program cost and total technologist's hours would be the following: CA-modified protocol, $37,441 and 376 hours; CDC protocol, $22,818 and 482 hours; and molecular testing, $224,596 and 343 hours.

The CDC screening protocol appeared to be the least expensive perirectal screening method. However, expense must be weighed against a lower sensitivity and extra labor needed for additional work-up of non-CPE isolates. The molecular test has the shortest turnaround time but the greatest expense.

To explore the feasibility of identifying anterior cruciate ligament (ACL) allograft implantations and infections using claims.

Retrospective cohort study.

We identified ACL reconstructions using procedure codes at 6 health plans from 2000 to 2008. We then identified potential infections using claims-based indicators of infection, including diagnoses, procedures, antibiotic dispensings, specialty consultations, emergency department visits, and hospitalizations. Patients’ medical records were reviewed to determine graft type, validate infection status, and calculate sensitivity and positive predictive value (PPV) for indicators of ACL allografts and infections.

A total of 11,778 patients with codes for ACL reconstruction were identified. After chart review, PPV for ACL reconstruction was 96% (95% confidence interval [CI], 94%–97%). Of the confirmed ACL reconstructions, 39% (95% CI, 35%–42%) used allograft tissues. The deep infection rate after ACL reconstruction was 1.0% (95% CI, 0.7%–1.4%). The odds ratio of infection for allografts versus autografts was 0.41 (95% CI, 0.19–0.78). Sensitivity of individual claims-based indicators for deep infection after ACL reconstruction ranged from 0% to 75% and PPV from 0% to 100%. Claims-based infection indicators could be combined to enhance sensitivity or PPV but not both.

While claims data accurately identify ACL reconstructions, they poorly distinguish between allografts and autografts and identify infections with variable accuracy. Claims data could be useful to monitor infection trends after ACL reconstruction, with different algorithms optimized for different surveillance goals.

Infect Control Hosp Epidemiol 2014;35(6):652–659

Characterize the clinical and molecular epidemiology of new methicillin-resistant Staphylococcus aureus (MRSA) acquisitions at nasal and extranasal sites among high-risk nursing home (NH) residents.

Multicenter prospective observational study.

Six NHs in southeast Michigan.

A total of 120 NH residents with an indwelling device (feeding tube and/or urinary catheter).

Active surveillance cultures from the nares, oropharynx, groin, perianal area, wounds (if present), and device insertion site(s) were collected upon enrollment, at day 14, and monthly thereafter. Pulsed-field gel electrophoresis and polymerase chain reaction for SCCmec, agr, and Panton-Valentine leukocidin were performed.

Of 120 participants observed for 16,290 device-days, 50 acquired MRSA (78% transiently, 22% persistently). New MRSA acquisitions were common in extranasal sites, particularly at device insertion, groin, and perianal areas (27%, 23%, and 17.6% of all acquisitions, respectively). Screening extranasal sites greatly increases the detection of MRSA colonization (100% of persistent carriers and 97.4% of transient carriers detected with nares, groin, perianal, and device site sampling vs 54.5% and 25.6%, respectively, for nares samples alone). Colonization at suprapubic urinary catheter sites generally persisted. Healthcare-associated MRSA (USA100 and USA100 variants) were the dominant strains (79.3% of all new acquisition isolates). Strain diversity was more common in transient carriers, including acquisition of USA500 and USA300 strains.

Indwelling device insertion sites as well as the groin and perianal area are important sites of new MRSA acquisitions in NH residents and play a role in the persistency of MRSA carriage. Clonal types differ among persistent and transient colonizers.

To evaluate whether dental treatment may enhance oral antisepsis, thus preventing more effectively lower respiratory tract infections (LRTIs) among critically ill patients

Observer-blind randomized clinical trial.

General intensive care unit (ICU) for adult patients.

We analyzed data from 254 adult patients who stayed for at least 48 hours in the ICU.

Patients were randomized by means of rolling dice. The experimental group (n = 127) had access to dental care provided by a dental surgeon, 4–5 times a week. Besides routine oral hygiene, care also included teeth brushing, tongue scraping, removal of calculus, atraumatic restorative treatment of caries, and tooth extraction. The control group (n = 127) had access to routine oral hygiene only, which included the use of chlorhexidine as a mouth rinse, which was performed by the ICU nurse staff.

The primary study outcome was the LRTI incidence, which was 8.7% in the experimental group and 18.1% in the control group (adjusted relative risk [RR], 0.44 [95% confidence interval (CI), 0.20–0.96]; P = .04). Ventilator-associated pneumonia rates per 1,000 ventilator-days were 16.5 (95% CI, 9.8–29.5) in the control group and 7.6 (95% CI, 3.3–15.0) in the experimental group (P < .05). Mortality rates were similar between both study groups: 31.5% in the control group versus 29.1% in the experimental group (adjusted RR, 0.93 [95% CI, 0.52–1.65]; P = .796). No severe adverse events related to oral care were observed during the study.

Dental treatment was safe and effective in the prevention of LRTI among critically ill patients who were expected to stay at least 48 hours in the ICU.

Brazilian Clinical Trials Registry, affiliated with the World Health Organization’s International Clinical Trial Registry Platform: U1111-1152-2671.

Infect Control Hosp Epidemiol 2014;35(11):1342–1348

To assess the impact of active alerting of positive blood culture data coupled with stewardship intervention on time to appropriate therapy, length of stay, and mortality in patients with gram-negative bacteremia.

Quasi-experimental retrospective cohort study in patients with gram-negative bacteremia at the Detroit Medical Center from 2009 to 2011.

Three hospitals (1 community, 2 academic) with active antimicrobial stewardship programs within the Detroit Medical Center.

All patients with monomicrobial gram-negative bacteremia during the study period.

Active alerting of positive blood culture data coupled with stewardship intervention (2010-2011) compared with patients who received no formalized stewardship intervention (2009).

Active alerting and intervention led to a decreased time to appropriate therapy (8 [interquartile range (IQR), 2-24] vs 14 [IQR, 2-35] hours; P = .014) in patients with gram-negative bacteremia. After controlling for differences between groups, being in the intervention arm was associated with an independent reduction in length of stay (odds ratio [OR], 0.73 [95% confidence interval (CI), 0.62-0.86]), correlating to a median attributable decrease in length of stay of 2.2 days. Additionally, multivariate modeling of patients who were not on appropriate antimicrobial therapy at the time of initial culture positivity showed that patients in the intervention group had a significant reduction in both length of stay (OR, 0.76 [95% CI, 0.66-0.86]) and infection-related mortality (OR, 0.24 [95% CI, 0.08-0.76]).

Active alerting coupled with stewardship intervention in patients with gram-negative bacteremia positively impacted time to appropriate therapy, length of stay, and mortality and should be a target of antimicrobial stewardship programs.

To determine rates of blood culture contamination comparing 3 strategies to prevent intensive care unit (ICU) infections: screening and isolation, targeted decolonization, and universal decolonization.

Pragmatic cluster-randomized trial.

Forty-three hospitals with 74 ICUs; 42 of 43 were community hospitals.

Patients admitted to adult ICUs from July 1, 2009, to September 30, 2011.

After a 6-month baseline period, hospitals were randomly assigned to 1 of 3 strategies, with all participating adult ICUs in a given hospital assigned to the same strategy. Arm 1 implemented methicillin-resistant Staphylococcus aureus (MRSA) nares screening and isolation, arm 2 targeted decolonization (screening, isolation, and decolonization of MRSA carriers), and arm 3 conducted no screening but universal decolonization of all patients with mupirocin and chlorhexidine (CHG) bathing. Blood culture contamination rates in the intervention period were compared to the baseline period across all 3 arms.

During the 6-month baseline period, 7,926 blood cultures were collected from 3,399 unique patients: 1,099 sets in arm 1, 928 in arm 2, and 1,372 in arm 3. During the 18-month intervention period, 22,761 blood cultures were collected from 9,878 unique patients: 3,055 sets in arm 1, 3,213 in arm 2, and 3,610 in arm 3. Among all individual draws, for arms 1,2, and 3, the contamination rates were 4.1%, 3.9%, and 3.8% for the baseline period and 3.3%, 3.2%, and 2.4% for the intervention period, respectively. When we evaluated sets of blood cultures rather than individual draws, the contamination rate in arm 1 (screening and isolation) was 9.8% (N = 108 sets) in the baseline period and 7.5% (N = 228) in the intervention period. For arm 2 (targeted decolonization), the baseline rate was 8.4% (N = 78) compared to 7.5% (N = 241) in the intervention period. Arm 3 (universal decolonization) had the greatest decrease in contamination rate, with a decrease from 8.7% (N = 119) contaminated blood cultures during the baseline period to 5.1% (N = 184) during the intervention period. Logistic regression models demonstrated a significant difference across the arms when comparing the reduction in contamination between baseline and intervention periods in both unadjusted (P = .02) and adjusted (P = .02) analyses. Arm 3 resulted in the greatest reduction in blood culture contamination rates, with an unadjusted odds ratio (OR) of 0.56 (95% confidence interval [CI], 0.044-0.71) and an adjusted OR of 0.55 (95% CI, 0.43-0.71).

In this large cluster-randomized trial, we demonstrated that universal decolonization with CHG bathing resulted in a significant reduction in blood culture contamination.

Hospitalizations for acute bacterial skin and skin structure infection (ABSSSI) are common. Optimizing antibiotic use for ABSSSIs requires an understanding of current management. The objective of this study was to evaluate antibiotic prescribing practices and factors affecting prescribing in a diverse group of hospitals

Multicenter, retrospective cohort study.

Seven community and academic hospitals.

Children and adults hospitalized between June 2010 and May 2012 for cellulitis, wound infection, or cutaneous abscess were eligible. The primary endpoint was a composite of 2 prescribing practices representing potentially avoidable antibiotic exposure: (1) use of antibiotics with a broad spectrum of activity against gram-negative bacteria or (2) treatment duration greater than 10 days.

A total of 533 cases were included: 320 with nonpurulent cellulitis, 44 with wound infection or purulent cellulitis, and 169 with abscess. Of 492 cases with complete prescribing data, the primary endpoint occurred in 394 (80%) cases and varied significantly across hospitals (64%–97%; P < .001). By logistic regression, independent predictors of the primary endpoint included wound infection or purulent cellulitis (odds ratio [OR], 5.12 [95% confidence interval (CI)], 1.46–17.88), head or neck involvement (OR, 2.83 [95% CI, 1.17–6.82]), adult cases (OR, 2.20 [95% CI, 1.18–4.11]), and admission to a community hospital (OR, 1.90 [95% CI, 1.05–3.44]).

Among patients hospitalized for ABSSSI, use of antibiotics with broad gram-negative activity or treatment courses longer than 10 days were common. There may be substantial opportunity to reduce antibiotic exposure through shorter courses of therapy targeting gram-positive bacteria.

Infect Control Hosp Epidemiol 2014;35(10):1241–1250

Patients hospitalized in post-acute care hospitals (PACHs) constitute an important reservoir of antimicrobial-resistant bacteria. High carriage prevalence of carbapenem-resistant Enterobacteriaceae (CRE) has been observed among patients hospitalized in PACHs. The objective of the study is to describe the impact of a national infection control intervention on the prevalence of CRE in PACHs.

A prospective cohort interventional study.

Thirteen PACHs in Israel.

A multifaceted intervention was initiated between 2008 and 2011 as part of a national program involving all Israeli healthcare facilities. The intervention has included (1) periodic on-site assessments of infection control policies and resources, using a score comprised of 16 elements; (2) assessment of risk factors for CRE colonization; (3) development of national guidelines for CRE control in PACHs involving active surveillance and contact isolation of carriers; and (4) 3 cross-sectional surveys of rectal carriage of CRE that were conducted in representative wards.

The infection control score increased from 6.8 to 14.0 (P < .001) over the course of the study period. A total of 3,516 patients were screened in the 3 surveys. Prevalence of carriage among those not known to be carriers decreased from 12.1% to 7.9% (P = .008). Overall carrier prevalence decreased from 16.8% to 12.5% (P = .013). Availability of alcohol-based hand rub, appropriate use of gloves, and a policy of CRE surveillance at admission to the hospital were independently associated with lower new carrier prevalence.

A nationwide infection control intervention was associated with enhanced infection control measures and a reduction in the prevalence of CRE in PACHs.

More than 10% of patients admitted to intensive care units (ICUs) experience a severe, healthcare-associated infection, such as ventilator-associated pneumonia (VAP) or bloodstream infection (BSI). What could be a public health target for prevention is hotly debated, because properly adjusting for intrinsic risk factors in the patient population is difficult. We aimed to estimate the proportion of ICU-acquired VAP and BSI cases that are amenable to prevention in routine conditions.

We analyzed routine data collected prospectively according to the European standard protocol for patient-based surveillance of healthcare-acquired infections in ICUs. We computed the number of infections to be expected if, after adjustment for case mix, the infection incidence in ICUs with higher infection rates could be reduced to that of the top-tenth-percentile-ranked ICU. Computations came from model-based simulation of individual patient profiles over time in the ICU. The preventable proportion was computed as the number of observed cases minus the number of expected cases divided by the number of observed cases.

Data for 78,222 patients admitted for more than 2 days to 525 ICUs in 6 European countries from 2005 to 2008 were available for analysis. We calculated that 52% of VAP and 69% of BSI was preventable.

Our pragmatic, if highly conservative, estimates quantify the potential for prevention of VAP and BSI in routine conditions, assuming that variation in infection incidence between ICUs can be eliminated with improved quality of care, apart from variation attributable to differential case mix.