We compared the individual-level risk of hospital-onset infections with multidrug-resistant organisms (MDROs) in hospitalized patients prior to and during the coronavirus disease 2019 (COVID-19) pandemic. We also quantified the effects of COVID-19 diagnoses and intrahospital COVID-19 burden on subsequent MDRO infection risk.

Multicenter, retrospective, cohort study.

Patient admission and clinical data were collected from 4 hospitals in the St. Louis area.

Data were collected for patients admitted between January 2017 and August 2020, discharged no later than September 2020, and hospitalized ≥48 hours.

Mixed-effects logistic regression models were fit to the data to estimate patients’ individual-level risk of infection with MDRO pathogens of interest during hospitalization. Adjusted odds ratios were derived from regression models to quantify the effects of the COVID-19 period, COVID-19 diagnosis, and hospital-level COVID-19 burden on individual-level hospital-onset MDRO infection probabilities.

We calculated adjusted odds ratios for COVID-19–era hospital-onset Acinetobacter spp., P. aeruginosa and Enterobacteriaceae spp infections. Probabilities increased 2.64 (95% confidence interval [CI], 1.22–5.73) times, 1.44 (95% CI, 1.03–2.02) times, and 1.25 (95% CI, 1.00–1.58) times relative to the prepandemic period, respectively. COVID-19 patients were 4.18 (95% CI, 1.98–8.81) times more likely to acquire hospital-onset MDRO S. aureus infections.

Our results support the growing body of evidence indicating that the COVID-19 pandemic has increased hospital-onset MDRO infections.

Dental healthcare personnel (DHCP) are at high risk of exposure to coronavirus disease 2019 (COVID-19). We sought to identify how DHCP changed their use of personal protective equipment (PPE) as a result of the COVID-19 pandemic, and to pilot an educational video designed to improve knowledge of proper PPE use.

The study comprised 2 sets of semistructured qualitative interviews.

The study was conducted in 8 dental clinics in a Midwestern metropolitan area.

In total, 70 DHCP participated in the first set of interviews; 63 DHCP participated in the second set of interviews.

In September–November 2020 and March–October 2021, we conducted 2 sets of semistructured interviews: (1) PPE use in the dental community during COVID-19, and (2) feedback on the utility of an educational donning and doffing video.

Overall, 86% of DHCP reported having prior training. DHCP increased the use of PPE during COVID-19, specifically N95 respirators and face shields. DHCP reported real-world challenges to applying infection control methods, often resulting in PPE modification and reuse. DHCP reported double masking and sterilization methods to extend N95 respirator use. Additional challenges to PPE included shortages, comfort or discomfort, and compatibility with specialty dental equipment. DHCP found the educational video helpful and relevant to clinical practice. Fewer than half of DHCP reported exposure to a similar video.

DHCP experienced significant challenges related to PPE access and routine use in dental clinics during the COVID-19 pandemic. An educational video improved awareness and uptake of appropriate PPE use among DHCP.

Patients on dialysis are at high risk for severe COVID-19 and associated morbidity and mortality. We examined the humoral response to SARS-CoV-2 mRNA vaccine BNT162b2 in a maintenance dialysis population.

Single-center cohort study.

Adult maintenance dialysis patients at 3 outpatient dialysis units of a large academic center.

Participants were vaccinated with 2 doses of BNT162b2, 3 weeks apart. We assessed anti–SARS-CoV-2 spike antibodies (anti-S) ∼4–7 weeks after the second dose and evaluated risk factors associated with insufficient response. Definitions of antibody response are as follows: nonresponse (anti-S level, <50 AU/mL), low response (anti-S level, 50–839 AU/mL), and sufficient response (anti-S level, ≥840 AU/mL).

Among the 173 participants who received 2 vaccine doses, the median age was 60 years (range, 28–88), 53.2% were men, 85% were of Black race, 86% were on in-center hemodialysis and 14% were on peritoneal dialysis. Also, 7 participants (4%) had no response, 27 (15.6%) had a low response, and 139 (80.3%) had a sufficient antibody response. In multivariable analysis, factors significantly associated with insufficient antibody response included end-stage renal disease comorbidity index score ≥5 and absence of prior hepatitis B vaccination response.

Although most of our study participants seroconverted after 2 doses of BNT162b2, 20% of our cohort did not achieve sufficient humoral response. Our findings demonstrate the urgent need for a more effective vaccine strategy in this high-risk patient population and highlight the importance of ongoing preventative measures until protective immunity is achieved.

Alteration of the colonic microbiota following antimicrobial exposure allows colonization by antimicrobial-resistant organisms (AROs). Ingestion of a probiotic, such as Lactobacillus rhamnosus GG (LGG), could prevent colonization or infection with AROs by promoting healthy colonic microbiota. The purpose of this trial was to determine the effect of LGG administration on ARO colonization in hospitalized patients receiving antibiotics.

Prospective, double-blinded, randomized controlled trial of LGG versus placebo among patients receiving broad-spectrum antibiotics.

Tertiary care center.

In total, 88 inpatients receiving broad-spectrum antibiotics were enrolled.

Patients were randomized to receive 1 capsule containing 1×1010 cells of LGG twice daily (n = 44) or placebo (n = 44), stratified by ward type. Stool or rectal-swab specimens were collected for culture at enrollment, during admission, and at discharge. Using selective media, specimens were cultured for Clostridioides difficile, vancomycin-resistant Enterococcus spp (VRE), and antibiotic-resistant gram-negative bacteria. The primary outcome was any ARO acquisition. Secondary outcomes included loss of any ARO if colonized at enrollment, and acquisition or loss of individual ARO.

ARO colonization prevalence at study enrollment was similar (LGG 39% vs placebo 39%). We detected no difference in any ARO acquisition (LGG 30% vs placebo 33%; OR,1.19; 95% CI, 0.38–3.75) nor for any individual ARO acquisition. There was no difference in the loss of any ARO (LGG 18% vs placebo 24%; OR, 1.44; 95% CI, 0.27–7.68) nor for any individual ARO.

LGG administration neither prevented acquisition of ARO nor accelerated loss of ARO colonization.

To assess potential transmission of antibiotic-resistant organisms (AROs) using surrogate markers and bacterial cultures.

Pilot study.

A 1,260-bed tertiary-care academic medical center.

The study included 25 patients (17 of whom were on contact precautions for AROs) and 77 healthcare personnel (HCP).

Fluorescent powder (FP) and MS2 bacteriophage were applied in patient rooms. HCP visits to each room were observed for 2–4 hours; hand hygiene (HH) compliance was recorded. Surfaces inside and outside the room and HCP skin and clothing were assessed for fluorescence, and swabs were collected for MS2 detection by polymerase chain reaction (PCR) and selective bacterial cultures.

Transfer of FP was observed for 20 rooms (80%) and 26 HCP (34%). Transfer of MS2 was detected for 10 rooms (40%) and 15 HCP (19%). Bacterial cultures were positive for 1 room and 8 HCP (10%). Interactions with patients on contact precautions resulted in fewer FP detections than interactions with patients not on precautions (P < .001); MS2 detections did not differ by patient isolation status. Fluorescent powder detections did not differ by HCP type, but MS2 was recovered more frequently from physicians than from nurses (P = .03). Overall, HH compliance was better among HCP caring for patients on contact precautions than among HCP caring for patients not on precautions (P = .003), among nurses than among other nonphysician HCP at room entry (P = .002), and among nurses than among physicians at room exit (P = .03). Moreover, HCP who performed HH prior to assessment had fewer fluorescence detections (P = .008).

Contact precautions were associated with greater HCP HH compliance and reduced detection of FP and MS2.

To determine the prevalence of Clostridium difficile colonization among patients who meet the 2017 IDSA/SHEA C. difficile infection (CDI) Clinical Guideline Update criteria for the preferred patient population for C. difficile testing.

Retrospective cohort.

Tertiary-care hospital in St. Louis, Missouri.

Patients whose diarrheal stool samples were submitted to the hospital’s clinical microbiology laboratory for C. difficile testing (toxin EIA) from August 2014 to September 2016.

Electronic and manual chart review were used to determine whether patients tested for C. difficile toxin had clinically significant diarrhea and/or any alternate cause for diarrhea. Toxigenic C. difficile culture was performed on all stool specimens from patients with clinically significant diarrhea and no known alternate cause for their diarrhea.

A total of 8,931 patients with stool specimens submitted were evaluated: 570 stool specimens were EIA positive (+) and 8,361 stool specimens were EIA negative (−). Among the EIA+stool specimens, 107 (19% of total) were deemed eligible for culture. Among the EIA− stool specimens, 515 (6%) were eligible for culture. One EIA+stool specimen (1%) was toxigenic culture negative. Among the EIA− stool specimens that underwent culture, toxigenic C. difficile was isolated from 63 (12%).

Most patients tested for C. difficile do not have clinically significant diarrhea and/or potential alternate causes for diarrhea. The prevalence of toxigenic C. difficile colonization among EIA− patients who met the IDSA/SHEA CDI guideline criteria for preferred patient population for C. difficile testing was 12%.

To evaluate healthcare worker (HCW) risk of self-contamination when donning and doffing personal protective equipment (PPE) using fluorescence and MS2 bacteriophage.

Prospective pilot study.

Tertiary-care hospital.

A total of 36 HCWs were included in this study: 18 donned/doffed contact precaution (CP) PPE and 18 donned/doffed Ebola virus disease (EVD) PPE.

HCWs donned PPE according to standard protocols. Fluorescent liquid and MS2 bacteriophage were applied to HCWs. HCWs then doffed their PPE. After doffing, HCWs were scanned for fluorescence and swabbed for MS2. MS2 detection was performed using reverse transcriptase PCR. The donning and doffing processes were videotaped, and protocol deviations were recorded.

Overall, 27% of EVD PPE HCWs and 50% of CP PPE HCWs made ≥1 protocol deviation while donning, and 100% of EVD PPE HCWs and 67% of CP PPE HCWs made ≥1 protocol deviation while doffing (P=.02). The median number of doffing protocol deviations among EVD PPE HCWs was 4, versus 1 among CP PPE HCWs. Also, 15 EVD PPE protocol deviations were committed by doffing assistants and/or trained observers. Fluorescence was detected on 8 EVD PPE HCWs (44%) and 5 CP PPE HCWs (28%), most commonly on hands. MS2 was recovered from 2 EVD PPE HCWs (11%) and 3 CP PPE HCWs (17%).

Protocol deviations were common during both EVD and CP PPE doffing, and some deviations during EVD PPE doffing were committed by the HCW doffing assistant and/or the trained observer. Self-contamination was common. PPE donning/doffing are complex and deserve additional study.

Infect Control Hosp Epidemiol 2017;38:1077–1083

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

To determine the attributable inpatient costs of recurrent Clostridium difficile infections (CDIs)

Retrospective cohort study.

Academic, urban, tertiary care hospital.

A total of 3,958 patients aged 18 years or more who developed an initial CDI episode from 2003 through 2009.

Data were collected electronically from hospital administrative databases and were supplemented with chart review. Patients with an index CDI episode during the study period were followed up for 180 days from the end of their index hospitalization or the end of their index CDI antibiotic treatment (whichever occurred later). Total hospital costs during the outcome period for patients with recurrent versus a single episode of CDI were analyzed using zero-inflated lognormal models.

There were 421 persons with recurrent CDI (recurrence rate, 10.6%). Recurrent CDI case patients were significantly more likely than persons without recurrence to have any hospital costs during the outcome period (P < .001). The estimated attributable cost of recurrent CDI was $11,631 (95% confidence interval, $8,937–$14,588).

The attributable costs of recurrent CDI are considerable. Patients with recurrent CDI are significantly more likely to have inpatient hospital costs than patients who do not develop recurrences. Better strategies to predict and prevent CDI recurrences are needed.

Infect Control Hosp Epidemiol 2014;35(11):1400–1407

To develop and validate a risk prediction model that could identify patients at high risk for Clostridium difficile infection (CDI) before they develop disease.

Retrospective cohort study in a tertiary care medical center.

Patients admitted to the hospital for at least 48 hours during the calendar year 2003.

Data were collected electronically from the hospital's Medical Informatics database and analyzed with logistic regression to determine variables that best predicted patients' risk for development of CDI. Model discrimination and calibration were calculated. The model was bootstrapped 500 times to validate the predictive accuracy. A receiver operating characteristic curve was calculated to evaluate potential risk cutoffs.

A total of 35,350 admitted patients, including 329 with CDI, were studied. Variables in the risk prediction model were age, CDI pressure, times admitted to hospital in the previous 60 days, modified Acute Physiology Score, days of treatment with high-risk antibiotics, whether albumin level was low, admission to an intensive care unit, and receipt of laxatives, gastric acid suppressors, or antimotility drugs. The calibration and discrimination of the model were very good to excellent (C index, 0.88; Brier score, 0.009).

The CDI risk prediction model performed well. Further study is needed to determine whether it could be used in a clinical setting to prevent CDI-associated outcomes and reduce costs.

To describe a pseudo-outbreak of Clostridium difficile infection (CDI) caused by a faulty toxin assay lot and to determine the effect of sensitivity, specificity, and repeated testing for C. difficile on perceived CDI burden, positive predictive value, and false-positive results.

Outbreak investigation and criterion standard.

Patients hospitalized at a tertiary care hospital who had at least 1 toxin assay for detection of C. difficile performed during the period from July 1, 2004, through June 30, 2006.

The run control chart method and the x2 test were used to compare CDI rates and the proportion of positive test results before, during, and after the pseudo-outbreak. The effect of repeated testing was evaluated by using 3 hypothetical models with a sample of 10,000 patients and various assay sensitivity and specificity estimates.

In November of 2005, the CDI rate at the hospital increased from 1.5 to 2.6 cases per 1,000 patient-days (P< .01), and the proportion of positive test results increased from 13.6% to 22.1% (P< .01). An investigation revealed a pseudo-outbreak caused by a faulty toxin assay lot. A decrease of only 1.2% in the specificity of the toxin assay would result in a 32% increase in perceived incidence of CDI at this institution. When calculated by use of the manufacturer's stated specificity and sensitivity and this institution's testing practices, the positive predictive value of the test decreased from 80.6% to 4.1% for patients who received 3 tests.

Specificity is as important as sensitivity when testing for CDI. False-positive CDI cases can drain hospital resources and adversely affect patients. Repeated testing for C. difficile should be performed with caution.

To compare Clostridium difficile infection (CDI) rates determined with use of a traditional definition (ie, with healthcare-onset CDI defined as diagnosis of CDI more than 48 hours after hospital admission) with rates determined with use of expanded definitions, including both healthcare-onset CDI and community-onset CDI, diagnosed within 48 hours after hospital admission in patients who were hospitalized in the previous 30 or 60 days, and to determine whether differences exist between patients with CDI onset in the community and those with CDI onset in a healthcare setting.

Prospective cohort

Tertiary acute care facility.

General medicine patients who received a diagnosis of CDI during the period January 1, 2004, through December 31, 2005.

CDI was classified as healthcare-onset CDI, healthcare facility–associated CDI after hospitalization within the previous 30 days, and/or healthcare facility-associated CDI after hospitalization within the previous 60 days. Patient demographic characteristics and medication exposures were obtained. The CDI incidence with use of each definition, CDI rate variability, patient demographic characteristics, and medication exposures were compared.

The healthcare-onset CDI rate (1.6 cases per 1,000 patient-days) was significantly lower than the 30-day healthcare facility–associated CDI rate (2.4 cases per 1,000 patient-days; P<.01) and the 60-day healthcare facility–associated CDI rate (2.6 cases per 1,000 patient-days; P<.01). There was good correlation between the healthcare-onset CDI rate and both the 30-day (correlation, 0.69; P<.01) and 60-day (correlation, 0.70; P<.01) healthcare facility–associated CDI rates. There were no months in which the CDI rate was more than 3 standard deviations from the mean. Compared with patients with healthcare-onset CDI, patients with community-onset CDI were less likely to have received a fourth-generation cephalosporin (P = .02) or intravenous vancomycin (P = .01) during hospitalization.

Compared with the traditional definition, expanded definitions identify more patients with CDI. There is good correlation between traditional and expanded CDI definitions; therefore, it is unclear whether expanded surveillance is necessary to identify an abnormal change in CDI rates. Cases that met the expanded definitions were less likely to have occurred in patients with fourth-generation cephalosporin and vancomycin exposure.