The maximum safe storage interval after endoscope reprocessing remains unknown. We assessed the association between storage interval and endoscope contamination to evaluate the need for scope reprocessing prior to use.

We conducted a study in 2 phases. In phase 1, we cultured 9 gastrointestinal (GI) endoscopes that had been stored for at least 7 days since reprocessing. Each scope was cultured in 3 places: external surfaces of hand piece, insertion tube, and internal channels. In phase 2, after reprocessing these scopes, we hung and cultured them prospectively in a similar fashion at 1-, 2-, 4-, 6-, and 8-week intervals without patient use. We defined clinically relevant contamination as >100 colony-forming units per milliliter (CFU/mL).

In phase 1, median hang time was 69 days (range, 8–555 days). Considering the 27 total cultures, 3 of 27 GI endoscopes (11.1%) had positive cultures, all with nonpathogenic skin flora at ≤100 CFU/mL. Median hang time was not statistically different between scopes with positive and negative cultures (P=.82). In phase 2, 7 of 131 prospective cultures (5.3%) from 6 of 9 GI endoscopes at varying storage intervals were positive, all at ≤100 CFU/mL. At 56 days after reprocessing (the longest storage interval studied), 1 of 24 cultures (4.2%) was positive (100 CFU/mL of Bacillus species from external biopsy/suction ports).

No endoscopes demonstrated clinically relevant contamination at hang times ranging from 7 to 555 days, and most scopes remained uncontaminated up to 56 days after reprocessing. Our data suggest that properly cleaned and disinfected GI endoscopes could be stored safely for longer intervals than currently recommended.

Infect. Control Hosp. Epidemiol. 2017;38:131–135

Endoscope-associated infections are reported despite following proper reprocessing methods. Microbiological testing can confirm the adequacy of endoscope reprocessing. Multiple controversies related to the method and interpretation of microbiological testing cultures have arisen that make their routine performance a complex target.

We conducted a pilot study using disposable bronchoscopes (DBs) to simulate different reprocessing times and soaking times and to compare high-level disinfection versus ethylene oxide sterilization. We also reviewed the time to reprocessing and duration of the procedures.

Bronchoscopes were chosen because an alternative disposable scope is commercially available and because bronchoscopes are more prone to delays in processing. Disposable bronchoscopes were contaminated using a liquid bacterial suspension and were then incubated for 1–4 hours. Standard processing and high-level disinfection were performed on 36 endoscopes. Ethylene oxide sterilization was performed on 21 endoscopes. Endoscope cultures were performed using the standard “brush, flush, brush” technique.

After brushing was performed, a final water-flush culture procedure was the most effective method of detecting bacterial persistence on the disposable scopes. Klebsiella pneumoniae was the most commonly recovered organism after reprocessing. Ethylene oxide sterilization did not result in total elimination of viable bacteria.

Routine endoscopy cultures may be required to assess the adequacy of endoscopic processing.

Infect Control Hosp Epidemiol 2017;38:136–142

Recently, robotic surgery has been introduced in many hospitals. The structure of robotic instruments is so complex that updating their cleaning methods is a challenge for healthcare professionals. However, there is limited information on the effectiveness of cleaning for instruments for robotic surgery.

To determine the level of residual contamination of instruments for robotic surgery and to develop a method to evaluate the cleaning efficacy for complex surgical devices.

Surgical instruments were collected immediately after operations and/or after in-house cleaning, and the level of residual protein was measured. Three serial measurements were performed on instruments after cleaning to determine the changes in the level of contamination and the total amount of residual protein. The study took place from September 1, 2013, through June 30, 2015, in Japan.

The amount of protein released from robotic instruments declined exponentially. The amount after in-house cleaning was 650, 550, and 530 µg/instrument in the 3 serial measurements. The overall level of residual protein in each measurement was much higher for robotic instruments than for ordinary instruments (P<.0001).

Our data demonstrated that complete removal of residual protein from surgical instruments is virtually impossible. The pattern of decline differed depending on the instrument type, which reflected the complex structure of the instruments. It might be necessary to establish a new standard for cleaning using a novel classification according to the structural complexity of instruments, especially for those for robotic surgery.

Infect Control Hosp Epidemiol 2017;38:143–146

Hip and knee arthroplasty infections are associated with considerable healthcare costs. The merits of reducing the postoperative surveillance period from 1 year to 90 days have been debated.

To report the first pan-Canadian hip and knee periprosthetic joint infection (PJI) rates and to describe the implications of a shorter (90-day) postoperative surveillance period.

Prospective surveillance for infection following hip and knee arthroplasty was conducted by hospitals participating in the Canadian Nosocomial Infection Surveillance Program (CNISP) using standard surveillance definitions.

Overall hip and knee PJI rates were 1.64 and 1.52 per 100 procedures, respectively. Deep incisional and organ-space hip and knee PJI rates were 0.96 and 0.71, respectively. In total, 93% of hip PJIs and 92% of knee PJIs were identified within 90 days, with a median time to detection of 21 days. However, 11%–16% of deep incisional and organ-space infections were not detected within 90 days. This rate was reduced to 3%–4% at 180 days post procedure. Anaerobic and polymicrobial infections had the shortest median time from procedure to detection (17 and 18 days, respectively) compared with infections due to other microorganisms, including Staphylococcus aureus.

PJI rates were similar to those reported elsewhere, although differences in national surveillance systems limit direct comparisons. Our results suggest that a postoperative surveillance period of 90 days will detect the majority of PJIs; however, up to 16% of deep incisional and organ-space infections may be missed. Extending the surveillance period to 180 days could allow for a better estimate of disease burden.

Infect Control Hosp Epidemiol 2017;38:147–153

We aimed to clarify whether invasive dental treatment is associated with increased risk of prosthetic joint infection (PJI) and whether prophylactic antibiotics may lower the infection risk remain unclear.

Retrospective cohort study.

All Taiwanese residents (N=255,568) who underwent total knee or hip arthroplasty between January 1, 1997, and November 30, 2009, were screened.

The dental cohort consisted of 57,066 patients who received dental treatment and were individually matched 1:1 with the nondental cohort by age, sex, propensity score, and index date. The dental cohort was further divided by the use or nonuse of prophylactic antibiotics. The antibiotic and nonantibiotic subcohorts comprised 6,513 matched pairs.

PJI occurred in 328 patients (0.57%) in the dental subcohort and 348 patients (0.61%) in the nondental subcohort, with no between-cohort difference in the 1-year cumulative incidence (0.6% in both, P=.3). Multivariate-adjusted Cox regression revealed no association between dental procedures and PJI. Furthermore, PJI occurred in 13 patients (0.2%) in the antibiotic subcohort and 12 patients (0.18%) in the nonantibiotic subcohorts (P=.8). Multivariate-adjusted analyses confirmed that there was no association between the incidence of PJI and prophylactic antibiotics.

The risk of PJI is not increased following dental procedure in patients with hip or knee replacement and is unaffected by antibiotic prophylaxis.

Infect Control Hosp Epidemiol. 2017;38:154–161

To assess whether differences in surveillance methods or underlying populations significantly influence internationally reported national SSI rates by comparing surveillance data from 2 countries.

Retrospective cohort.

England and Norway.

We assessed the population under surveillance and surveillance methodology to compare SSI rates in 2 countries (September 2012–January 2015) for 4 surgical categories: coronary artery bypass graft (CABG), colon surgery, cholecystectomy, and hip prosthesis (HPRO). We compared the inpatient SSI incidence using logistic regression, adjusting for the following known risk factors: sex, age, ASA score, wound class, postoperative hospital days, and operation duration. Subsequently, we restricted further analyses to the procedures reported by both countries.

There were important differences in case definitions for superficial infection, so we restricted our analyses to deep incisional and organ-space SSIs. For CABG, the crude odds ratio (OR) for England compared to Norway was 2.4 (95% CI, 1.4–4.4), whereas adjusted OR (aOR) lost significance (aOR, 1.1; 95% CI, 0.57–2.0). For colon surgery the decreased odds (OR, 0.68; 95% CI, 0.56–0.81) remained significant after adjustment (aOR, 0.42; 95% CI, 0.34–0.51). We found no associations for cholecystectomy. For HPRO, the crude OR suggested no significant difference (OR, 1.2; 95% CI, 0.72–2.1), whereas the aOR was significantly lower in England (aOR, 0.45; 95% CI, 0.25–0.81). Including only the subset of procedures reported by both countries yielded comparable results.

Differences in case definitions and population under surveillance in the English and Norwegian SSI surveillance systems affected SSI estimates, making the comparison of crude rates unreliable. Standardized definitions and adjustment for established risk factors are essential for European comparisons to guide related public health actions.

Infect Control Hosp Epidemiol 2017;38:162–171

To compare interrater reliabilities for ventilator-associated event (VAE) surveillance, traditional ventilator-associated pneumonia (VAP) surveillance, and clinical diagnosis of VAP by intensivists.

A retrospective study nested within a prospective multicenter quality improvement study.

Intensive care units (ICUs) within 5 hospitals of the Centers for Disease Control and Prevention Epicenters.

Patients who underwent mechanical ventilation.

We selected 150 charts for review, including all VAEs and traditionally defined VAPs identified during the primary study and randomly selected charts of patients without VAEs or VAPs. Each chart was independently reviewed by 2 research assistants (RAs) for VAEs, 2 hospital infection preventionists (IPs) for traditionally defined VAP, and 2 intensivists for any episodes of pulmonary deterioration. We calculated interrater agreement using κ estimates.

The 150 selected episodes spanned 2,500 ventilator days. In total, 93–96 VAEs were identified by RAs; 31–49 VAPs were identified by IPs, and 29–35 VAPs were diagnosed by intensivists. Interrater reliability between RAs for VAEs was high (κ, 0.71; 95% CI, 0.59–0.81). Agreement between IPs using traditional VAP criteria was slight (κ, 0.12; 95% CI, −0.05–0.29). Agreement between intensivists was slight regarding episodes of pulmonary deterioration (κ 0.22; 95% CI, 0.05–0.39) and was fair regarding whether episodes of deterioration were attributable to clinically defined VAP (κ, 0.34; 95% CI, 0.17–0.51). The clinical correlation between VAE surveillance and intensivists’ clinical assessments was poor.

Prospective surveillance using VAE criteria is more reliable than traditional VAP surveillance and clinical VAP diagnosis; the correlation between VAEs and clinically recognized pulmonary deterioration is poor.

Infect Control Hosp Epidemiol 2017;38:172–178

To determine the origin of grouped cases of Pneumocystis pneumonia in solid-organ transplant recipients at our institution.

A case series with clinical examinations, genotyping, and an epidemiological survey.

A university hospital in France.

We report 12 solid-organ transplant recipients with successive cases of Pneumocystis pneumonia that occurred over 3 years; 10 of these cases occurred in a single year.

We used molecular typing of P. jirovecii strains by multilocus sequence typing and clinical epidemiological survey to determine potential dates and places of transmission.

Between May 2014 and March 2015, 10 solid-organ transplant recipients (5 kidney transplants, 4 heart transplants, and 1 lung transplant) presented with Pneumocystis pneumonia. Molecular genotyping revealed the same P. jirovecii strain in at least 6 patients. This Pneumocystis strain was not identified in control patients (ie, nontransplant patients presenting with pulmonary pneumocystosis) during this period. The epidemiological survey guided by sequencing results provided information on the probable or possible dates and places of contamination for 5 of these patients. The mobile infectious diseases unit played a coordination role in the clinical management (adaptation of the local guidelines) and epidemiological survey.

Our cardiac and kidney transplant units experienced grouped cases of pulmonary pneumocystosis. Genotyping and epidemiological surveying results suggested interhuman contamination, which was quickly eliminated thanks to multidisciplinary coordination.

Infect Control Hosp Epidemiol 2017;38:179–185

Catheter-associated urinary tract infections (CAUTIs) are among the most common hospital-acquired infections (HAIs). Reducing CAUTI rates has become a major focus of attention due to increasing public health concerns and reimbursement implications.

To implement and describe a multifaceted intervention to decrease CAUTIs in our ICUs with an emphasis on indications for obtaining a urine culture.

A project team composed of all critical care disciplines was assembled to address an institutional goal of decreasing CAUTIs. Interventions implemented between year 1 and year 2 included protocols recommended by the Centers for Disease Control and Prevention for placement, maintenance, and removal of catheters. Leaders from all critical care disciplines agreed to align routine culturing practice with American College of Critical Care Medicine (ACCCM) and Infectious Disease Society of America (IDSA) guidelines for evaluating a fever in a critically ill patient. Surveillance data for CAUTI and hospital-acquired bloodstream infection (HABSI) were recorded prospectively according to National Healthcare Safety Network (NHSN) protocols. Device utilization ratios (DURs), rates of CAUTI, HABSI, and urine cultures were calculated and compared.

The CAUTI rate decreased from 3.0 per 1,000 catheter days in 2013 to 1.9 in 2014. The DUR was 0.7 in 2013 and 0.68 in 2014. The HABSI rates per 1,000 patient days decreased from 2.8 in 2013 to 2.4 in 2014.

Effectively reducing ICU CAUTI rates requires a multifaceted and collaborative approach; stewardship of culturing was a key and safe component of our successful reduction efforts.

Infect Control Hosp Epidemiol 2017;38:186–188

Recently, the US Food and Drug Administration requested that a “maximal use” trial be conducted to ensure the safety of frequent use of alcohol-based hand rubs (ABHRs) by healthcare workers.

To establish how frequently volunteers should be exposed to ABHR during a maximal use trial.

Retrospective review of literature and analysis of 2 recent studies that utilized hand hygiene electronic compliance monitoring (ECM) systems.

We reviewed PubMed for articles published between 1970 and December 31, 2015, containing the terms hand washing, hand hygiene, hand hygiene compliance, and alcohol-based hand rubs. Article titles, abstracts, or text were reviewed to determine whether the frequency of ABHR use by healthcare workers was reported. Two studies using hand hygiene ECM systems were reviewed to determine how frequently nurses used ABHR per shift and per hour.

Of 3,487 citations reviewed, only 10 reported how frequently individual healthcare workers used ABHR per shift or per hour. Very conservative estimates of the frequency of ABHR use were reported owing to shortcomings of the methods utilized. The greatest frequency of ABHR use was recorded by an ECM system in a medical intensive care unit. In 95% of nursing shifts, individual nurses used ABHR 141 times or less per shift, and 15 times or less per hour.

Hand hygiene ECM systems established that the frequency of exposure to ABHRs varies substantially among nurses. Our findings should be useful in designing how frequently individuals should be exposed to ABHR during a maximal use trial.

Infect Control Hosp Epidemiol 2017;38:189–195

Clostridium difficile infection (CDI) is the most common healthcare-associated infection and is associated with considerable morbidity. Recurrent CDI is a key contributing factor to this morbidity. Despite an estimated 83,000 recurrences annually in the United States, there are few accurate estimates of costs associated with recurrent CDI.

We performed this study (1) to identify the health consequences of recurrent CDI including need for repeat hospitalization, intensive care unit (ICU) stay, and surgery; (2) to determine costs associated with recurrent CDI and identify determinants of such costs; and (3) to compare the outcomes and costs of recurrent CDI to those who develop reinfection.

We identified all patients with confirmed recurrent CDI between January to December 2013 at a single referral center. Healthcare burden associated with recurrence including diagnostic testing, pharmacologic treatment, and inpatient and outpatient healthcare visits were identified in the 12 months following the first recurrence. Total healthcare costs were calculated, and the predictors of high healthcare utilization were identified.

Our study population included 98 patients with recurrent CDI. The median interval between the initial infection and recurrence was 37 days. The mean age of the cohort was 67 years, two-thirds were women (62%), and the mean Charlson index was 8.6. During the year following the first recurrence of CDI, each patient underwent a mean of 4.4 stool C. difficile toxin tests and received a mean of 2.5 prescriptions for oral vancomycin (range, 0–6). Most patients (84%) with recurrence had a CDI-related hospitalization, and 6% underwent colectomy. The mean total CDI-associated cost was $34,104 per patient, with hospitalization costs accounting for 68%, surgery 20%, and drug treatment 8% of this cost, respectively. Extrapolating to the United States overall, we estimate an annual cost of $2.8 billion related to recurrent CDI.

Recurrent CDI is associated with considerable morbidity and cost.

Infect Control Hosp Epidemiol 2017;38:196–202

Information about the health and economic impact of infections caused by vancomycin-resistant enterococci (VRE) can inform investments in infection prevention and development of novel therapeutics.

To systematically review the incidence of VRE infection in the United States and the clinical and economic outcomes.

We searched various databases for US studies published from January 1, 2000, through June 8, 2015, that evaluated incidence, mortality, length of stay, discharge to a long-term care facility, readmission, recurrence, or costs attributable to VRE infections. We included multicenter studies that evaluated incidence and single-center and multicenter studies that evaluated outcomes. We kept studies that did not have a denominator or uninfected controls only if they assessed postinfection length of stay, costs, or recurrence. We performed meta-analysis to pool the mortality data.

Five studies provided incidence data and 13 studies evaluated outcomes or costs. The incidence of VRE infections increased in Atlanta and Detroit but did not increase in national samples. Compared with uninfected controls, VRE infection was associated with increased mortality (pooled odds ratio, 2.55), longer length of stay (3-4.6 days longer or 1.4 times longer), increased risk of discharge to a long-term care facility (2.8- to 6.5-fold) or readmission (2.9-fold), and higher costs ($9,949 higher or 1.6-fold more).

VRE infection is associated with large attributable burdens, including excess mortality, prolonged in-hospital stay, and increased treatment costs. Multicenter studies that use suitable controls and adjust for time at risk or confounders are needed to estimate the burden of VRE infections.

Infect Control Hosp Epidemiol. 2017;38:203–215

(1) To systematically search for all dynamic mathematical models of infectious disease transmission in long-term care facilities (LTCFs); (2) to critically evaluate models of interventions against antimicrobial resistance (AMR) in this setting; and (3) to develop a checklist for hospital epidemiologists and policy makers by which to distinguish good quality models of AMR in LTCFs.

The CINAHL, EMBASE, Global Health, MEDLINE, and Scopus databases were systematically searched for studies of dynamic mathematical models set in LTCFs. Models of interventions targeting methicillin-resistant Staphylococcus aureus in LTCFs were critically assessed. Using this analysis, we developed a checklist for good quality mathematical models of AMR in LTCFs.

Overall, 18 papers described mathematical models that characterized the spread of infectious diseases in LTCFs, but no models of AMR in gram-negative bacteria in this setting were described. Future models of AMR in LTCFs require a more robust methodology (ie, formal model fitting to data and validation), greater transparency regarding model assumptions, setting-specific data, realistic and current setting-specific parameters, and inclusion of movement dynamics between LTCFs and hospitals.

Mathematical models of AMR in gram-negative bacteria in the LTCF setting, where these bacteria are increasingly becoming prevalent, are needed to help guide infection prevention and control. Improvements are required to develop outputs of sufficient quality to help guide interventions and policy in the future. We suggest a checklist of criteria to be used as a practical guide to determine whether a model is robust enough to test policy.

Infect Control Hosp Epidemiol 2017;38:216–225