Prevalence of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Asymptomatic Infections in 2 Large Academic Health Systems in Wisconsin.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) asymptomatic infections may play a critical role in disease transmission. We aim to determine the prevalence of asymptomatic SARS-CoV-2 infection at 2 hospital systems in 2 counties in Wisconsin. The SARS-CoV-2 prevalence was 1% or lower at both systems despite the higher incidence of coronavirus disease 2019 (COVID-19) in Milwaukee County.

Transmission Dynamics of Clostridioides difficile in 2 High-Acuity Hospital Units.

BACKGROUND: The key epidemiological drivers of Clostridioides difficile transmission are not well understood. We estimated epidemiological parameters to characterize variation in C. difficile transmission, while accounting for the imperfect nature of surveillance tests. METHODS: We conducted a retrospective analysis of C. difficile surveillance tests for patients admitted to a bone marrow transplant (BMT) unit or a solid tumor unit (STU) in a 565-bed tertiary hospital. We constructed a transmission model for estimating key parameters, including admission prevalence, transmission rate, and duration of colonization to understand the potential variation in C. difficile dynamics between these 2 units. RESULTS: A combined 2425 patients had 5491 admissions into 1 of the 2 units. A total of 3559 surveillance tests were collected from 1394 patients, with 11% of the surveillance tests being positive for C. difficile. We estimate that the transmission rate in the BMT unit was nearly 3-fold higher at 0.29 acquisitions per percentage colonized per 1000 days, compared to our estimate in the STU (0.10). Our model suggests that 20% of individuals admitted into either the STU or BMT unit were colonized with C. difficile at the time of admission. In contrast, the percentage of surveillance tests that were positive within 1 day of admission to either unit for C. difficile was 13.4%, with 15.4% in the STU and 11.6% in the BMT unit. CONCLUSIONS: Although prevalence was similar between the units, there were important differences in the rates of transmission and clearance. Influential factors may include antimicrobial exposure or other patient-care factors.

Elastomeric Respirators for COVID-19 and the Next Respiratory Virus Pandemic: Essential Design Elements.

Respiratory viruses are transmitted via respiratory particles that are emitted when people breath, speak, cough, or sneeze. These particles span the size spectrum from visible droplets to airborne particles of hundreds of nanometers. Barrier face coverings ("cloth masks") and surgical masks are loose-fitting and provide limited protection from airborne particles since air passes around the edges of the mask as well as through the filtering material. Respirators, which fit tightly to the face, provide more effective respiratory protection. Although healthcare workers have relied primarily on disposable filtering facepiece respirators (such as N95) during the COVID-19 pandemic, reusable elastomeric respirators have significant potential advantages for the COVID-19 and future respiratory virus pandemics. However, currently available elastomeric respirators were not designed primarily for healthcare or pandemic use and require further development to improve their suitability for this application. The authors believe that the development, implementation, and stockpiling of improved elastomeric respirators should be an international public health priority.

Infection Prevention Precautions for Routine Anesthesia Care During the SARS-CoV-2 Pandemic.

Many health care systems around the world continue to struggle with large numbers of SARS-CoV-2-infected patients, while others have diminishing numbers of cases following an initial surge. There will most likely be significant oscillations in numbers of cases for the foreseeable future, based on the regional epidemiology of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Less affected hospitals and facilities will attempt to progressively resume elective procedures and surgery. Ramping up elective care in hospitals that deliberately curtailed elective care to focus on SARS-CoV-2-infected patients will present unique and serious challenges. Among the challenges will be protecting patients and providers from recurrent outbreaks of disease while increasing procedure throughput. Anesthesia providers will inevitably be exposed to SARS-CoV-2 by patients who have not been diagnosed with infection. This is particularly concerning in consideration that aerosols produced during airway management may be infective. In this article, we recommend an approach to routine anesthesia care in the setting of persistent but variable prevalence of SARS-CoV-2 infection. We make specific recommendations for personal protective equipment and for the conduct of anesthesia procedures and workflow based on evidence and expert opinion. We propose practical, relatively inexpensive precautions that can be applied to all patients undergoing anesthesia. Because the SARS-CoV-2 virus is spread primarily by respiratory droplets and aerosols, effective masking of anesthesia providers is of paramount importance. Hospitals should follow the recommendations of the Centers for Disease Control and Prevention for universal masking of all providers and patients within their facilities. Anesthesia providers should perform anesthetic care in respirator masks (such as N-95 and FFP-2) whenever possible, even when the SARS-CoV-2 test status of patients is negative. Attempting to screen patients for infection with SARS-CoV-2, while valuable, is not a substitute for respiratory protection of providers, as false-negative tests are possible and infected persons can be asymptomatic or presymptomatic. Provision of adequate supplies of respirator masks and other respiratory protection equipment such as powered air purifying respirators (PAPRs) should be a high priority for health care facilities and for government agencies. Eye protection is also necessary because of the possibility of infection from virus coming into contact with the conjunctiva. Because SARS-CoV-2 persists on surfaces and may cause infection by contact with fomites, hand hygiene and surface cleaning are also of paramount importance.

Clostridium difficile in Immunocompromised Hosts: A Review of Epidemiology, Risk Factors, Treatment, and Prevention.

Clostridium difficile is a significant pathogen in healthcare today, impacting both hospitalized and community-based patients. Immunocompromised patients experience a high incidence of C. difficile infection, ranging from 6% to 33% in the hematology-oncology population and up to 23% among lung transplant recipients, and have a rate of 7.1-8.3 cases per 1000 patient-years in patients with human immunodeficiency virus (HIV). Recurrence of C. difficile infections among immunocompromised patients is also high, with rates up to 40% in both the hematology-oncology population and solid organ transplant recipients. This higher incidence of C. difficile infection and recurrence is believed to be secondary to frequent antimicrobial use, suppressed immune function, increased exposure to healthcare settings, and higher prevalence of C. difficile colonization. This review summarizes published data describing the epidemiology, risk factors for acquisition and infection, treatment, and prevention of C. difficile in hematology-oncology, solid organ transplant, and HIV-infected patients.

The Juncture Between Clostridioides difficile Infection and Inflammatory Bowel Diseases.

The detection of Clostridioides difficile in inflammatory bowel disease (IBD) patients is a common occurrence, in part due to the standard clinical practice of testing for the presence of C. difficile during acute IBD exacerbations. Given the clinical overlap between C. difficile infections and acute IBD exacerbations (ie, increased frequency of loose stools, abdominal pain), it is hard to differentiate C. difficile infections versus colonizations in patients with underlying IBD who test positive for C. difficile. Here, we review the epidemiology, clinical presentation, risk factors, diagnosis, treatment, and outcomes of IBD patients with positive C. difficile tests.

Patient-to-Patient Transmission of Klebsiella pneumoniae Carbapenemase Variants with Reduced Ceftazidime-Avibactam Susceptibility.

We report patient-to-patient transmission of Enterobacter hormaechei isolates with reduced susceptibility to ceftazidime-avibactam due to production of KPC-40, a variant of KPC-3 with a two-amino-acid insertion in the Ω-loop region (L167_E168dup). The index patient had received a prolonged course of ceftazidime-avibactam therapy, whereas the second patient had not received the agent and still became colonized with the KPC-40-producing strain. The complex dynamics of KPC (Klebsiella pneumoniae carbapenemase) described here highlight several key diagnostic and therapeutic considerations.

Handling Time-dependent Variables: Antibiotics and Antibiotic Resistance.

Elucidating quantitative associations between antibiotic exposure and antibiotic resistance development is important. In the absence of randomized trials, observational studies are the next best alternative to derive such estimates. Yet, as antibiotics are prescribed for varying time periods, antibiotics constitute time-dependent exposures. Cox regression models are suited for determining such associations. After explaining the concepts of hazard, hazard ratio, and proportional hazards, the effects of treating antibiotic exposure as fixed or time-dependent variables are illustrated and discussed. Wider acceptance of these techniques will improve quantification of the effects of antibiotics on antibiotic resistance development and provide better evidence for guideline recommendations.

Evaluating the Impact of Antibiotic Exposures as Time-Dependent Variables on the Acquisition of Carbapenem-Resistant Acinetobacter baumannii.

OBJECTIVES: To determine the time-dependent effect of antibiotics on the initial acquisition of carbapenem-resistant Acinetobacter baumannii. DESIGN: Retrospective cohort study. SETTING: Forty-bed trauma ICU in Miami, FL. PATIENTS: All consecutive patients admitted to the unit from November 1, 2010, to November 30, 2011. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Patients underwent surveillance cultures at admission to the unit and weekly thereafter. The primary outcome was the acquisition of carbapenem-resistant A. baumannii on surveillance cultures. Daily antibiotic exposures during the time of observation were used to construct time-dependent variables, including cumulative exposures (in grams and daily observed doses [defined daily doses]). Among 360 patients, 45 (12.5%) became colonized with carbapenem-resistant A. baumannii. Adjusted Cox models showed that each additional point in the Acute Physiologic and Chronic Health Evaluation score increased the hazard by 4.8% (hazard ratio, 1.048; 95% CI, 1.010-1.087; p = 0.0124) and time-dependent exposure to carbapenems quadrupled the hazard (hazard ratio, 4.087; 95% CI, 1.873-8.920; p = 0.0004) of acquiring carbapenem-resistant A. baumannii. Additionally, adjusted Cox models determined that every additional carbapenem defined daily dose increased the hazard of acquiring carbapenem-resistant A. baumannii by 5.1% (hazard ratio, 1.051; 95% CI, 1.007-1.093; p = 0.0243). CONCLUSIONS: Carbapenem exposure quadrupled the hazards of acquiring A. baumannii even after controlling for severity of illness.

Surveillance cultures growing carbapenem-Resistant Acinetobacter baumannii predict the development of clinical infections: a retrospective cohort study.

BACKGROUND: We aimed to determine the effect of the presence of carbapenem-resistant Acinetobacter baumannii in accordance with surveillance cultures on the subsequent development of clinical infections by this organism. METHODS: This retrospective cohort study was conducted at a tertiary hospital from January 2010 to November 2011. We included all consecutive patients admitted to the trauma intensive care unit, who had weekly surveillance cultures performed (from rectum, and if intubated, respiratory secretions), and without evidence of A. baumannii infections prior to the collection of the first surveillance culture. Univariable and multivariable analyses were performed using log-binomial regression. Survival analyses were performed using Cox proportional hazards. RESULTS: Three hundred sixty-four patients were included, of whom 49 (13.5%) had carbapenem-resistant A. baumannii on surveillance cultures. Patients with positive surveillance cultures had 8.4 (95% confidence interval [CI], 5.6-12.7; P < .0001) times the risk of developing a subsequent A. baumannii infection compared with patients who remained negative on surveillance cultures. Multivariable analysis showed significant associations between clinical infection and both positive surveillance cultures (relative risk [RR], 5.9 [95% CI, 3.8-9.3]; P < .0001) and mechanical ventilation (RR, 4.3 [95% CI, 1.03-18.2]; P = .05). On survival analyses, the only variable associated with the development of clinical infections was the presence of positive surveillance cultures (hazard ratio, 16.3 [95% CI, 9.1-29.1]; P < .001). CONCLUSIONS: Presence of carbapenem-resistant A. baumannii on surveillance cultures is strongly associated with subsequent development of carbapenem-resistant A. baumannii infections. Prevention efforts should be focused at limiting the acquisition of this organism during hospitalization.

Contamination of Ambient Air with Acinetobacter baumannii on Consecutive Inpatient Days.

Acinetobacter-positive patients had their ambient air tested for up to 10 consecutive days. The air was Acinetobacter positive for an average of 21% of the days; the rate of contamination was higher among patients colonized in the rectum than in the airways (relative risk [RR], 2.35; P = 0.006). Of the 6 air/clinical isolate pairs available, 4 pairs were closely related according to rep-PCR results.

A New Approach to Pathogen Containment in the Operating Room: Sheathing the Laryngoscope After Intubation.

BACKGROUND: Anesthesiologists may contribute to postoperative infections by means of the transmission of blood and pathogens to the patient and the environment in the operating room (OR). Our primary aims were to determine whether contamination of the IV hub, the anesthesia work area, and the patient could be reduced after induction of anesthesia by removing the risk associated with contaminants on the laryngoscope handle and blade. Therefore, we conducted a study in a simulated OR where some of the participants sheathed the laryngoscope handle and blade in a glove immediately after it was used to perform an endotracheal intubation. METHODS: Forty-five anesthesiology residents (postgraduate year 2-4) were enrolled in a study consisting of identical simulation sessions. On entry to the simulated OR, the residents were asked to perform an anesthetic, including induction and endotracheal intubation timed to approximately 6 minutes. Of the 45 simulation sessions, 15 were with a control group conducted with the intubating resident wearing single gloves, 15 with the intubating resident using double gloves with the outer pair removed and discarded after verified intubation, and 15 wearing double gloves and sheathing the laryngoscope in one of the outer gloves after intubation. Before the start of the scenario, the lips and inside of the mouth of the mannequin were coated with a fluorescent marking gel. After each of the 45 simulations, an observer examined the OR using an ultraviolet light to determine the presence of fluorescence on 25 sites: 7 on the patient and 18 in the anesthesia environment. RESULTS: Of the 7 sites on the patient, ultraviolet light detected contamination on an average of 5.7 (95% confidence interval, 4.4-7.2) sites under the single-glove condition, 2.1 (1.5-3.1) sites with double gloves, and 0.4 (0.2-1.0) sites with double gloves with sheathing. All 3 conditions were significantly different from one another at P < 0.001. Of the 18 environmental sites, ultraviolet light detected fluorescence on an average of 13.2 (95% confidence interval, 11.3-15.6) sites under the single-glove condition, 3.5 (2.6-4.7) with double gloves, and 0.5 (0.2-1.0) with double gloves with sheathing. Again, all 3 conditions were significantly different from one another at P < 0.001. CONCLUSIONS: The results of this study suggest that when an anesthesiologist in a simulated OR sheaths the laryngoscope immediately after endotracheal intubation, contamination of the IV hub, patient, and intraoperative environment is significantly reduced.

Double gloves: a randomized trial to evaluate a simple strategy to reduce contamination in the operating room.

BACKGROUND: Oral flora, blood-borne pathogens, and bacterial contamination pose a direct risk of infection to patients and health care workers. We conducted a study in a simulated operating room using a newly validated technology to determine whether the use of 2 sets of gloves, with the outer set removed immediately after endotracheal intubation, may reduce this risk. METHODS: Forty-one anesthesiology residents (PGY 2-4) were enrolled in a study consisting of individual or group simulation sessions. On entry to the simulated operating room, the residents were asked to perform an anesthetic induction and tracheal intubation timed to approximately 6 minutes; they were unaware of the study design. Of the 22 simulation sessions, 11 were conducted with the intubating resident wearing single gloves, and 11 with the intubating resident using double gloves with the outer pair removed after verified intubation. Before the start of the scenario, we coated the lips and inside of the mouth of the mannequin with a fluorescent marking gel as a surrogate pathogen. After the simulation, an observer examined 40 different sites using a handheld ultraviolet light in the operating room to determine the transfer of surrogate pathogens to the patient and the patient's environment. Residents who wore double gloves were instructed by a confederate nurse to remove the outer set immediately after completion of the intubation. Forty sites of potential intraoperative pathogen spread were identified and assigned a score. RESULTS: The difference in the rate of contamination between anesthesiology residents who wore single gloves versus those with double gloves was clinically and statistically significant. The number of sites that were contaminated in the operating room when the intubating resident wore single gloves was 20.3 ± 1.4 (mean ± SE); the number of contaminated sites when residents wore double gloves was 5.0 ± 0.7 (P < 0.001). CONCLUSIONS: The results of this study suggest that when an anesthesiologist wears 2 sets of gloves during laryngoscopy and intubation and then removes the outer set immediately after intubation, the contamination of the intraoperative environment is dramatically reduced.

The use of a novel technology to study dynamics of pathogen transmission in the operating room.

Pathogenic organisms have been found in the intraoperative environment, potentially posing a risk of infection that could cause morbidity and mortality. In an effort to understand how a patient's bacteria can be spread throughout the operating room with the anesthesia provider as a vector, we conducted a study using recently developed experimental technology in a simulated operating room environment with a high-fidelity human patient simulator.

Effect of high perioperative oxygen supplementation on surgical site infections.

Over the past 15 years, several randomized controlled trials, long-term follow-up studies, meta-analyses, and editorials have been published in regard to the effect of a high fraction of inspired oxygen concentration (FiO(2)) during the perioperative period on the incidence of surgical site infections. Although the evidence is not uniformly favorable for all types of surgeries, a beneficial association of 80% FiO(2) has been documented among open abdominal procedures, especially colorectal surgeries.