The nationally reported metric for Clostridium difficile infection (CDI) relies solely on laboratory testing, which can result in overreporting due to asymptomatic C. difficile colonization.

To review the clinical scenarios of cases of healthcare facility-onset CDI (HO-CDI) and to determine the appropriateness of C. difficile testing on the basis of presence of symptomatic diarrhea in order to identify areas for improvement.

Retrospective cohort study.

Northwestern Memorial Hospital, a large, tertiary academic hospital in Chicago, Illinois.

The cohort included all patients with a positive C. difficile test result who were reported to the National Healthcare Safety Network as HO-CDI during a 1-year study period.

We reviewed the clinical scenario of each HO-CDI case. On the basis of documentation and predefined criteria, appropriateness of C. difficile testing was determined; cases were deemed appropriate, inappropriate, or indeterminate. Statistical analysis was performed to compare demographic and clinical parameters among the categories of testing appropriateness.

Our facility reported 168 HO-CDI cases to NHSN during the study period. Of 168 cases, 33 (19.6%) were judged to be appropriate tests, 25 (14.8%) were considered inappropriate, and 110 (65.5%) were indeterminate. Elimination of inappropriate testing would have improved our facility’s standardized infection ratio from 0.962 to 0.819.

Approximately 15% of HO-CDI cases were judged to be tested inappropriately. Testing only patients with clinically significant diarrhea would more accurately estimate CDI incidence, reduce unnecessary antibiotic use, and improve facilities’ performance of reportable CDI metrics. Improved documentation could facilitate targeted interventions.

Infect Control Hosp Epidemiol 2016;1395–1400

To determine whether Clostridium difficile is present in the food of hospitalized patients and to estimate the risk of subsequent colonization associated with C. difficile in food.

This was a prospective cohort study of inpatients at a university-affiliated tertiary care center, May 9, 2011–July 12, 2012. Enrolled patients submitted a portion of food from each meal. Patient stool specimens and/or rectal swabs were collected at enrollment, every 3 days thereafter, and at discharge, and were cultured for C. difficile. Clinical data were reviewed for evidence of infection due to C. difficile. A stochastic, discrete event model was developed to predict exposure to C. difficile from food, and the estimated number of new colonization events from food exposures per 1,000 admissions was determined.

A total of 149 patients were enrolled and 910 food specimens were obtained. Two food specimens from 2 patients were positive for C. difficile (0.2% of food samples; 1.3% of patients). Neither of the 2 patients was colonized at baseline with C. difficile. Discharge colonization status was available for 1 of the 2 patients and was negative. Neither was diagnosed with C. difficile infection while hospitalized or during the year before or after study enrollment. Stochastic modeling indicated contaminated hospital food would be responsible for less than 1 newly colonized patient per 1,000 hospital admissions.

The recovery of C. difficile from the food of hospitalized patients was rare. Modeling suggests hospital food is unlikely to be a source of C. difficile acquisition.

Infect Control Hosp Epidemiol 2016;1401–1407

Clostridium difficile is the principal infectious cause of antibiotic-associated diarrhea and accounts for 12% of hospital-acquired infections. Recent literature has shown an increased risk of C. difficile infection (CDI) with proton pump inhibitor (PPI) use.

To conduct a systematic assessment of the risk of hospital-acquired CDI following exposure to PPI.

We searched multiple databases for studies examining the relationship between PPI and hospital-acquired CDI. Pooled odds ratios were generated and assessment for heterogeneity performed.

We found 23 observational studies involving 186,033 cases that met eligibility criteria. Across studies, 10,307 cases of hospital-acquired CDI were reported. Significant heterogeneity was present; therefore, a random effects model was used. The pooled odds ratio was 1.81 (95% CI, 1.52–2.14), favoring higher risk of CDI with PPI use. Significant heterogeneity was present, likely due to differences in assessment of exposure, study population, and definition of CDI.

This meta-analysis suggests PPIs significantly increase the risk of hospital-acquired CDI. Given the significant health and economic burden of CDI and the risks of PPI, optimization of PPI use should be included in a multifaceted approach to CDI prevention.

Infect Control Hosp Epidemiol 2016;1408–1417

To study the association between gastrointestinal colonization of carbapenemase-producing Enterobacteriaceae (CPE) and proton pump inhibitors (PPIs).

We analyzed 31,526 patients with prospective collection of fecal specimens for CPE screening: upon admission (targeted screening) and during hospitalization (opportunistic screening, safety net screening, and extensive contact tracing), in our healthcare network with 3,200 beds from July 1, 2011, through December 31, 2015. Specimens were collected at least once weekly during hospitalization for CPE carriers and subjected to broth enrichment culture and multiplex polymerase chain reaction.

Of 66,672 fecal specimens collected, 345 specimens (0.5%) from 100 patients (0.3%) had CPE. The number and prevalence (per 100,000 patient-days) of CPE increased from 2 (0.3) in 2012 to 63 (8.0) in 2015 (P<.001). Male sex (odds ratio, 1.91 [95% CI, 1.15–3.18], P=.013), presence of wound or drain (3.12 [1.70–5.71], P<.001), and use of cephalosporins (3.06 [1.42–6.59], P=.004), carbapenems (2.21 [1.10–4.48], P=.027), and PPIs (2.84 [1.72–4.71], P<.001) in the preceding 6 months were significant risk factors by multivariable analysis. Of 79 patients with serial fecal specimens, spontaneous clearance of CPE was noted in 57 (72.2%), with a median (range) of 30 (3–411) days. Comparing patients without use of antibiotics and PPIs, consumption of both antibiotics and PPIs after CPE identification was associated with later clearance of CPE (hazard ratio, 0.35 [95% CI, 0.17–0.73], P=.005).

Concomitant use of antibiotics and PPIs prolonged duration of gastrointestinal colonization by CPE.

Infect Control Hosp Epidemiol 2016;1418–1425

To determine the typical microbial bioburden (overall bacterial and multidrug-resistant organisms [MDROs]) on high-touch healthcare environmental surfaces after routine or terminal cleaning.

Prospective 2.5-year microbiological survey of large surface areas (>1,000 cm2).

MDRO contact-precaution rooms from 9 acute-care hospitals and 2 long-term care facilities in 4 states.

Samples from 166 rooms (113 routine cleaned and 53 terminal cleaned rooms).

Using a standard sponge-wipe sampling protocol, 2 composite samples were collected from each room; a third sample was collected from each Clostridium difficile room. Composite 1 included the TV remote, telephone, call button, and bed rails. Composite 2 included the room door handle, IV pole, and overbed table. Composite 3 included toileting surfaces. Total bacteria and MDROs (ie, methicillin-resistant Staphylococcus aureus, vancomycin-resistant enterococci [VRE], Acinetobacter baumannii, Klebsiella pneumoniae, and C. difficile) were quantified, confirmed, and tested for drug resistance.

The mean microbial bioburden and range from routine cleaned room composites were higher (2,700 colony-forming units [CFU]/100 cm2; ≤1–130,000 CFU/100 cm2) than from terminal cleaned room composites (353 CFU/100 cm2; ≤1–4,300 CFU/100 cm2). MDROs were recovered from 34% of routine cleaned room composites (range ≤1–13,000 CFU/100 cm2) and 17% of terminal cleaned room composites (≤1–524 CFU/100 cm2). MDROs were recovered from 40% of rooms; VRE was the most common (19%).

This multicenter bioburden summary provides a first step to determining microbial bioburden on healthcare surfaces, which may help provide a basis for developing standards to evaluate cleaning and disinfection as well as a framework for studies using an evidentiary hierarchy for environmental infection control.

Infect Control Hosp Epidemiol 2016;1426–1432

To evaluate risk factors for and molecular characteristics of community-onset extended-spectrum cephalosporin-resistant (ESC-R) Enterobacteriaceae (EB) urinary tract infections (UTIs) in a US health system.

Case-control study.

All patients presenting to the emergency department or outpatient practices with EB UTIs from December 21, 2010, through April 22, 2013, were included. Case patients had ESC-R EB UTIs. Control patients had ESC-susceptible EB UTIs and were matched 1:1 on study year.

Risk factors for ESC-R EB UTI were assessed using multivariable conditional logistic regression. A subset of case isolates was evaluated for extended-spectrum beta-lactamases.

A total of 302 patients with community-onset EB UTI were included, of which 151 were cases. On multivariable analysis, risk factors for ESC-R EB UTI included trimethoprim-sulfamethoxazole use in the prior 6 months (odds ratio, 2.40 [95% CI, 1.22–4.70]; P=.01), older age (1.03 [1.01–1.04]; P<.001), diabetes (2.91 [1.32–6.41]; P=.008), and presentation to the emergency department ( 2.42 [1.31–4.46]; P=.005). The prevalence of extended-spectrum beta-lactamases among 120 case isolates was 52% CTX-M, 29% TEM, 20% OXA, and 13% SHV. The prevalence of AmpC was 25%. Pulsed-field gel electrophoresis of the CTX-M Escherichia coli isolates showed no distinct clusters.

Use of trimethoprim-sulfamethoxazole, older age, diabetes, and presentation to the emergency department were associated with community-onset ESC-R EB UTI. There was a high prevalence of CTX-M among our community isolates. Further studies are needed to determine strategies to limit emergence of these organisms in the community.

Infect Control Hosp Epidemiol 2016;1433–1439

To facilitate surveillance and describe the burden of healthcare-associated infection (HAI) in nursing homes (NHs), we compared the quality of resident-level data collected by NH personnel and external staff.

A 1-day point-prevalence survey

Overall, 9 nursing homes among 4 Centers for Disease Control and Prevention (CDC) Emerging Infection Program (EIP) sites were included in this study.

NH personnel collected data on resident characteristics, clinical risk factors for HAIs, and the presence of 3 HAI screening criteria on the day of the survey. Trained EIP surveillance officers collected the same data elements via retrospective medical chart review for comparison; surveillance officers also collected available data to identify HAIs (using revised McGeer definitions). Overall agreement was calculated among residents identified by both teams with selected risk factors and HAI screening criteria. The impact of using NH personnel to collect screening criteria on HAI prevalence was assessed.

The overall prevalence of clinical risk factors among the 1,272 residents was similar between NH personnel and surveillance officers, but the level of positive agreement (residents with factors identified by both teams) varied between 39% and 87%. Surveillance officers identified 253 residents (20%) with ≥1 HAI screening criterion, resulting in 67 residents with an HAI (5.3 per 100 residents). The NH personnel identified 152 (12%) residents with ≥1 HAI screening criterion; 42 residents had an HAI (3.5 per 100 residents).

We identified discrepancies in resident-level data collection between surveillance officers and NH personnel, resulting in varied estimates of the HAI prevalence. These findings have important implications for the design and implementation of future HAI prevalence surveys.

Infect Control Hosp Epidemiol 2016;1440–1445

Central-line–associated bloodstream infections (CLABSI) are an important cause of morbidity and mortality in neonates. We aimed to determine whether intra-abdominal pathologies are an independent risk factor for CLABSI.

We performed a retrospective matched case–control study of infants admitted to the neonatal intensive care units (NICUs) of the Montreal Children’s Hospital (Montreal) and the Royal Alexandra Hospital, Edmonton, Canada. CLABSI cases that occurred between April 2009 and March 2014 were identified through local infection control databases. For each case, up to 3 controls were matched (National Healthcare Safety Network [NHSN] birth weight category, chronological age, and central venous catheter (CVC) dwell time at the time of CLABSI onset). Data were analyzed using conditional logistic regression.

We identified 120 cases and 293 controls. According to a matched univariate analysis, the following variables were significant risk factors for CLABSI: active intra-abdominal pathology (odds ratio [OR], 3.4; 95% confidence interval [CI], 1.8–6.4), abdominal surgery in the prior 7 days (OR, 3.5; 95% CI, 1.0–10.9); male sex (OR, 1.7; 95% CI, 1.1–2.6) and ≥3 heel punctures (OR, 4.0; 95% CI, 1.9–8.3). According to a multivariate matched analysis, intra-abdominal pathology (OR, 5.9; 95% CI, 2.5–14.1), and ≥3 heel punctures (OR, 5.4; 95% CI, 2.4–12.2) remained independent risk factors for CLABSI.

The presence of an active intra-abdominal pathology increased the risk of CLABSI by almost 6-fold. Similar to CLABSI in oncology patients, a subgroup of CLABSI with mucosal barrier injury should be considered for infants in the NICU with active intra-abdominal pathology.

Infect Control Hosp Epidemiol 2016;1446–1452

Ventilator-associated events (VAEs) are nosocomial events correlated with length of stay, costs, and mortality. Current ventilator bundle practices target the older definition of ventilator-associated pneumonia and have not been systematically evaluated for their impact on VAEs.

Retrospective cohort study.

Tertiary medical center between January 2012 and August 2014.

All adult patients ventilated for at least 24 hours at our institution.

We conducted univariate analyses for compliance with each element; we focused on VAEs occurring within a 2-day window of failure to meet any ventilator bundle element. We used Cox proportional hazard models to assess the effect of stress ulcer prophylaxis, deep vein thrombosis (DVT) prophylaxis, oral care, and sedation breaks on VAEs. We adjusted models for gender, age, and Acute Physiology and Chronic Health Evaluation (APACHE) III scores.

Our cohort comprised 2,660 patients with 16,858 ventilator days and 77 VAEs. Adjusting for APACHE score and gender, only oral care was associated with a reduction in the risk of VAE (hazard ratio [HR], 0.44; 95% confidence interval [CI], 0.26–0.77). The DVT prophylaxis and sedation breaks did not show any significant impact on VAEs. Stress ulcer prophylaxis trended toward an increased risk of VAE (HR, 1.59; 95% CI, 1.00–2.56).

Although limited by a low baseline rate of VAEs, existing ventilator bundle practices do not appear to target VAEs well. Oral care is clearly important, but the impact of DVT prophylaxis, sedation breaks, and especially stress ulcer prophylaxis are questionable at best.

Infect Control Hosp Epidemiol 2016;1453–1457

To identify risk factors for surgical site infections (SSIs) after spine operations.

Case-control study of SSIs among patients undergoing spine operations.

An academic health center.

We studied patients undergoing spinal fusions or laminectomies at the University of Iowa Hospitals and Clinics from January 1, 2007, through June 30, 2009. We included patients who acquired SSIs meeting the National Healthcare Safety Network definition. We randomly selected controls among patients who had spine operations during the study period and did not meet the SSI definition.

In total, 54 patients acquired SSIs after 2,309 spine operations (2.3 per 100 procedures). SSIs were identified a median of 20 days after spinal fusions and 17 days after laminectomies; 90.7% were identified after discharge and 72.2% were deep incisional or organ-space infections. Staphylococcus aureus caused 53.7% of SSIs. Of patients with SSIs, 64.9% (fusion) and 70.6% (laminectomy) were readmitted and 59.5% (fusion) and 64.7% (laminectomy) underwent reoperation. By multivariable analysis, increased body mass index, Surgical Department A, fusion of 4–8 vertebrae, and operation at a thoracic or lumbar/sacral level were significant risk factors for SSIs after spinal fusions. Lack of private insurance and hypertension were significant risk factors for SSIs after laminectomies. Surgeons from Department A were more likely to use nafcillin or vancomycin for perioperative prophylaxis and to do more multilevel fusions than surgeons from Department B.

SSIs after spine operations significantly increase utilization of healthcare resources. Possible remediable risk factors include obesity, hypertension, and perioperative antimicrobial prophylaxis.

Infect Control Hosp Epidemiol 2016;1458–1467

The goal of this long-term quasi-experimental retrospective study was to assess the impact of a 5-year serial infection control and antimicrobial stewardship intervention on surgical site infections (SSIs).

This study was conducted in a tertiary-care public teaching institution over a 5-year period from January 2010 to December 2014. All patients undergoing hepatobiliary surgery and liver, kidney, pancreas, and simultaneous pancreas–kidney transplantation were included. Outcomes were compared between a preintervention group (2010–2011) and a postintervention group (2012–2014).

A total of 1,424 procedures averaged an overall SSI rate of 11.2%. After implementation of the interventions, a decrease of 52.8% in SSI rates from 17.4% to 8.2% was observed (P<.001; odds ratio [OR], 2.1; 95% confidence interval [CI], 1.5–2.9). An overall significant decrease >50% (relative rate; P<.001) was observed in superficial incisional and organ-space infections between pre- and postintervention groups. In addition, a 54.9% decrease from 19.7% to 8.9% (P<.001; OR, 2.2; 95% CI, 1.4–3.5) and a 51.6% decrease from 15.5% to 7.5% (P=.001; OR, 2.2; 95% CI, 1.4–3.5) were observed for SSI rates in hepatobiliary surgery and solid organ transplantation, respectively. The antimicrobial stewardship intervention increased overall conformity to the internal surgical prophylaxis protocol by 15.2% (absolute rate) from 45.1% to 60.3% (P<.003; 95% CI, 5.4–24.9).

A long-term serial infection control and antimicrobial stewardship intervention decreased SSIs among patients undergoing hepatobiliary surgery and liver, kidney, pancreas, and simultaneous pancreas–kidney transplantation.

Infect Control Hosp Epidemiol 2016;1468–1474

To determine the source of a Legionella pneumophila serogroup 5 nosocomial outbreak and the role of the heat exchanger installed on the hot water system within the previous year.

A 400-bed tertiary care university hospital in Sherbrooke, Canada.

Hot water samples were collected and cultured for L. pneumophila from 25 taps (baths and sinks) within wing A and 9 taps in wing B. Biofilm (5) and 2 L water samples (3) were collected within the heat exchangers for L. pneumophila culture and detection of protists. Sequence-based typing was performed on strain DNA extracts and pulsed-field gel electrophoresis patterns were analyzed.

Following 2 cases of hospital-acquired legionellosis, the hot water system investigation revealed a large proportion of L. pneumophila serogroup 5 positive taps (22/25 in wing A and 5/9 in wing B). High positivity was also detected in the heat exchanger of wing A in water samples (3/3) and swabs from the heat exchanger (4/5). The outbreak genotyping investigation identified the hot water system as the source of infections. Genotyping results revealed that all isolated environmental strains harbored the same related pulsed-field gel electrophoresis pattern and sequence-based type.

Two cases of hospital-acquired legionellosis occurred in the year following the installation of a heat exchanger to preheat hospital hot water. No cases were reported previously, although the same L. pneumophila strain was isolated from the hot water system in 1995. The heat exchanger promoted L. pneumophila growth and may have contributed to confirmed clinical cases.

Infect. Control Hosp. Epidemiol. 2016;1475–1480