Water exposures in healthcare settings and during healthcare delivery can place patients at risk for infection with water-related organisms and can potentially lead to outbreaks. We aimed to describe Centers for Disease Control and Prevention (CDC) consultations involving water-related organisms leading to healthcare-associated infections (HAIs).

Retrospective observational study.

We reviewed internal CDC records from January 1, 2014, through December 31, 2017, using water-related terms and organisms, excluding Legionella, to identify consultations that involved potential or confirmed transmission of water-related organisms in healthcare. We determined plausible exposure pathways and routes of transmission when possible.

Of 620 consultations during the study period, we identified 134 consultations (21.6%), with 1,380 patients, that involved the investigation of potential water-related HAIs or infection control lapses with the potential for water-related HAIs. Nontuberculous mycobacteria were involved in the greatest number of investigations (n = 40, 29.9%). Most frequently, investigations involved medical products (n = 48, 35.8%), and most of these products were medical devices (n = 40, 83.3%). We identified a variety of plausible water-exposure pathways, including medication preparation near water splash zones and water contamination at the manufacturing sites of medications and medical devices.

Water-related investigations represent a substantial proportion of CDC HAI consultations and likely represent only a fraction of all water-related HAI investigations and outbreaks occurring in US healthcare facilities. Water-related HAI investigations should consider all potential pathways of water exposure. Finally, healthcare facilities should develop and implement water management programs to limit the growth and spread of water-related organisms.

Surveillance of dialysis-related bloodstream infections (DRBSIs) has been mandatory in Québec since April 2011. The aim of this study was to describe the epidemiology of DRBSIs in Québec.

Cohort study of prevalent patients undergoing chronic dialysis in the 36 facilities that participated without interruption in the provincial surveillance, between April 2011 and March 2017. Two indicators were analyzed: proportion of patient months dialyzed using a fistula (a patient month is a 28-day cycle during which an individual patient received dialysis) and incidence rate of DRBSI. Binomial and Poisson regression with generalized estimating equations were used to describe the evolution of indicators over time and to quantify the association between facilities’ proportion of fistulas and their incidence rate.

Globally, 42.6% of all patient months were dialyzed using a fistula, but there was a statistically significant decrease over time (46.2% in 2011–2012 to 39.3% in 2016–2017). Despite this decline in the use of fistulas, rates of DRBSIs have also decreased, going from 0.38 DRBSIs per 100 patient months in 2011–2012 to 0.23 DRBSIs per 100 patient months in 2016–2017. No association was found between facility use of fistulas and the rate of DRBSI. At the individual level, however, the DRBSI rate was 4.12 times higher for patients using a catheter.

In Québec, the rate of DRBSIs has decreased over a 6-year period despite an increasing proportion of patients dialyzed by catheter.

Central-line–associated bloodstream infections (CLABSIs) are a known complication of central venous access. Pulmonary artery catheters (PAC) are frequently used in pre–heart-transplant patients, but the rate of CLABSI in this population is unknown. We sought to estimate the rate of CLABSI and identify factors associated with development of infection in patients actively listed for heart transplantation with a PAC.

Retrospective cohort study.

This study was conducted in 3 intensive care units at an academic tertiary-care center in Minnesota.

61 pre–heart-transplant patients in an intensive care unit with a PAC in place from January 2013 to December 2016, totaling 219 PACs.

At-risk patients, pertinent risk factors, and demographic data were obtained using Mayo Clinic’s Unified Data Platform. CLABSIs were identified through internal infection prevention and control data. Characteristics of PAC use and infection rate were collected and analyzed using Kaplan-Meier estimates and time-dependent Cox models.

Among pre–heart-transplant patients with a PAC, there were 14 CLABSIs, for an infection rate of 5.46 of 1,000 PAC days (95% confidence interval [CI], 2.98–9.15). The most common causative organism was coagulase-negative Staphylococcus (79%). In unadjusted analyses, CLABSI was associated with shorter time to transplant (hazard ratio [HR], 2.49; P = .027), but not mortality (HR, 1.79; P = .355).

The rate of CLABSI with PAC is high. Prolonged PAC use in the pre–heart-transplant population should be revisited.

To compare risk of surgical site infection (SSI) following cesarean delivery between women covered by Medicaid and private health insurance.

Retrospective cohort.

Cesarean deliveries covered by Medicaid or private insurance and reported to the National Healthcare Safety Network (NHSN) and state inpatient discharge databases by hospitals in California (2011–2013).

Deliveries reported to NHSN and state inpatient discharge databases were linked to identify SSIs in the 30 days following cesarean delivery, primary payer, and patient and procedure characteristics. Additional hospital-level characteristics were obtained from public databases. Relative risk of SSI by primary payer primary payer was assessed using multivariable logistic regression adjusting for patient, procedure, and hospital characteristics, accounting for facility-level clustering.

Of 291,757 cesarean deliveries included, 48% were covered by Medicaid. SSIs were detected following 1,055 deliveries covered by Medicaid (0.75%) and 955 deliveries covered by private insurance (0.63%) (unadjusted odds ratio, 1.2; 95% confidence interval [CI], 1.1–1.3; P < .0001). The adjusted odds of SSI following cesarean deliveries covered by Medicaid was 1.4 (95% CI, 1.2–1.6; P < .0001) times the odds of those covered by private insurance.

In this, the largest and only multicenter study to investigate SSI risk following cesarean delivery by primary payer, Medicaid-insured women had a higher risk of infection than privately insured women. These findings suggest the need to evaluate and better characterize the quality of maternal healthcare for and needs of women covered by Medicaid to inform targeted infection prevention and policy.

Determining infectious cross-transmission events in healthcare settings involves manual surveillance of case clusters by infection control personnel, followed by strain typing of clinical/environmental isolates suspected in said clusters. Recent advances in genomic sequencing and cloud computing now allow for the rapid molecular typing of infecting isolates.

To facilitate rapid recognition of transmission clusters, we aimed to assess infection control surveillance using whole-genome sequencing (WGS) of microbial pathogens to identify cross-transmission events for epidemiologic review.

Clinical isolates of Staphylococcus aureus, Enterococcus faecium, Pseudomonas aeruginosa, and Klebsiella pneumoniae were obtained prospectively at an academic medical center, from September 1, 2016, to September 30, 2017. Isolate genomes were sequenced, followed by single-nucleotide variant analysis; a cloud-computing platform was used for whole-genome sequence analysis and cluster identification.

Most strains of the 4 studied pathogens were unrelated, and 34 potential transmission clusters were present. The characteristics of the potential clusters were complex and likely not identifiable by traditional surveillance alone. Notably, only 1 cluster had been suspected by routine manual surveillance.

Our work supports the assertion that integration of genomic and clinical epidemiologic data can augment infection control surveillance for both the identification of cross-transmission events and the inclusion of missed and exclusion of misidentified outbreaks (ie, false alarms). The integration of clinical data is essential to prioritize suspect clusters for investigation, and for existing infections, a timely review of both the clinical and WGS results can hold promise to reduce HAIs. A richer understanding of cross-transmission events within healthcare settings will require the expansion of current surveillance approaches.

To estimate the burden of Clostridium difficile infections (CDIs) due to interfacility patient sharing at regional and hospital levels.

Retrospective observational study.

We used data from the Healthcare Cost and Utilization Project California State Inpatient Database (2005–2011) to identify 26,878,498 admissions and 532,925 patient transfers. We constructed a weighted, directed network among the hospitals by defining an edge between 2 hospitals to be the monthly average number of patients discharged from one hospital and admitted to another on the same day. We then used a network autocorrelation model to study the effect of the patient sharing network on the monthly average number of CDI cases per hospital, and we estimated the proportion of CDI cases attributable to the network.

We found that 13% (95% confidence interval [CI], 7.6%–18%) of CDI cases were due to diffusion through the patient-sharing network. The network autocorrelation parameter was estimated at 5.0 (95% CI, 3.0–6.9). An increase in the number of patients transferred into and/or an increased CDI rate at the hospitals from which those patients originated led to an increase in the number of CDIs in the receiving hospital.

A minority but substantial burden of CDI infections are attributable to hospital transfers. A hospital’s infection control may thus be nontrivially influenced by its neighboring hospitals. This work adds to the growing body of evidence that intervention strategies designed to minimize HAIs should be done at the regional rather than local level.

To determine whether oral vancomycin prophylaxis accompanying systemic antibiotics reduces the risk of relapse in patients with history of Clostridioides difficile infection (CDI).

Retrospective cohort study.

Adult inpatients with a history of CDI who received systemic antibiotics in either of 2 hospitals between January 2009 and June 2015.

We compared relapse rates in patients who started oral vancomycin concurrently with systemic antibiotics (exposed group) versus those who did not. We assessed for CDI relapse by toxin or nucleic acid testing at 90 days. We used inverse probability weighting and machine learning to adjust for confounders, to estimate propensity for treatment, and to calculate odds ratios for CDI relapse. We performed secondary analyses limited to toxin-positive relapses, patients with 1 versus >1 prior CDI episodes, and patients who received oral vancomycin on each antibiotic day.

CDI relapse occurred within 90 days in 19 of 193 exposed patients (9.8%) versus 53 of 567 unexposed patients (9.4%; unadjusted odds ratio [OR], 1.06; 95% confidence interval [CI], 0.60–1.81; adjusted OR, 0.63; 95% CI, 0.35–1.14). CDI relapses at 90 days were less frequent in exposed patients with only 1 prior episode of CDI (OR, 0.42; 95% CI, 0.19–0.93) but not in those with >1 prior episode (OR, 1.19; 95% CI, 0.42–3.33). Our findings were consistent with a lack of benefit of oral vancomycin when restricting results to toxin-positive relapses and to patients who received vancomycin each antibiotic day.

Prophylactic oral vancomycin was not consistently associated with reduced risk of CDI relapse among hospitalized patients receiving systemic antibiotics. However, patients with only 1 prior CDI episode may benefit.

To evaluate the impact of a hard stop in the electronic health record (EHR) on inappropriate gastrointestinal pathogen panel testing (GIPP).

We used a quasi-experimental study to evaluate testing before and after the implementation of an EHR alert to stop inappropriate GIPP ordering.

Midwest academic medical center.

Hospitalized patients with diarrhea for which GIPP testing was ordered, between January 2016 through March 2017 (period 1) and April 2017 through June 2018 (period 2).

A hard stop in the EHR prevented clinicians from ordering a GIPP more than once per admission or in patients hospitalized for >72 hours.

During period 1, 1,587 GIPP tests were ordered over 212,212 patient days, at a rate of 7.48 per 1,000 patient days. In period 2, 1,165 GIPP tests were ordered over 222,343 patient days, at a rate of 5.24 per 1,000 patient days. The Poisson model estimated a 30% reduction in total GIPP ordering rates between the 2 periods (relative risk, 0.70; 95% confidence interval [CI], 0.63–0.78; P < .001). The rate of inappropriate tests ordered decreased from 21.5% to 4.9% between the 2 periods (P < .001). The total savings calculated factoring only GIPP orders that triggered the hard stop was ∼$67,000, with potential savings of $168,000 when factoring silent best-practice alert data.

A simple hard stop alert in the EHR resulted in significant reduction of inappropriate GIPP testing, which was associated with significant cost savings. Clinicians can practice diagnostic stewardship by avoiding ordering this test more than once per admission or in patients hospitalized >72 hours.

In cluster-randomized trials (CRT), groups rather than individuals are randomized to interventions. The aim of this study was to present critical design, implementation, and analysis issues to consider when planning a CRT in the healthcare setting and to synthesize characteristics of published CRT in the field of healthcare epidemiology.

A systematic review was conducted to identify CRT with infection control outcomes.

We identified the following 7 epidemiological principles: (1) identify design type and justify the use of CRT; (2) account for clustering when estimating sample size and report intraclass correlation coefficient (ICC)/coefficient of variation (CV); (3) obtain consent; (4) define level of inference; (5) consider matching and/or stratification; (6) minimize bias and/or contamination; and (7) account for clustering in the analysis. Among 44 included studies, the most common design was CRT with crossover (n = 15, 34%), followed by parallel CRT (n = 11, 25%) and stratified CRT (n = 7, 16%). Moreover, 22 studies (50%) offered justification for their use of CRT, and 20 studies (45%) demonstrated that they accounted for clustering at the design phase. Only 15 studies (34%) reported the ICC, CV, or design effect. Also, 15 studies (34%) obtained waivers of consent, and 7 (16%) sought consent at the cluster level. Only 17 studies (39%) matched or stratified at randomization, and 10 studies (23%) did not report efforts to mitigate bias and/or contamination. Finally, 29 studies (88%) accounted for clustering in their analyses.

We must continue to improve the design and reporting of CRT to better evaluate the effectiveness of infection control interventions in the healthcare setting.