The role of severe respiratory coronavirus virus 2 (SARS-CoV-2)–laden aerosols in the transmission of coronavirus disease 2019 (COVID-19) remains uncertain. Discordant findings of SARS-CoV-2 RNA in air samples were noted in early reports.

Sampling of air close to 6 asymptomatic and symptomatic COVID-19 patients with and without surgical masks was performed with sampling devices using sterile gelatin filters. Frequently touched environmental surfaces near 21 patients were swabbed before daily environmental disinfection. The correlation between the viral loads of patients’ clinical samples and environmental samples was analyzed.

All air samples were negative for SARS-CoV-2 RNA in the 6 patients singly isolated inside airborne infection isolation rooms (AIIRs) with 12 air changes per hour. Of 377 environmental samples near 21 patients, 19 (5.0%) were positive by reverse-transcription polymerase chain reaction (RT-PCR) assay, with a median viral load of 9.2 × 102 copies/mL (range, 1.1 × 102 to 9.4 × 104 copies/mL). The contamination rate was highest on patients’ mobile phones (6 of 77, 7.8%), followed by bed rails (4 of 74, 5.4%) and toilet door handles (4 of 76, 5.3%). We detected a significant correlation between viral load ranges in clinical samples and positivity rate of environmental samples (P < .001).

SARS-CoV-2 RNA was not detectable by air samplers, which suggests that the airborne route is not the predominant mode of transmission of SARS-CoV-2. Wearing a surgical mask, appropriate hand hygiene, and thorough environmental disinfection are sufficient infection control measures for COVID-19 patients isolated singly in AIIRs. However, this conclusion may not apply during aerosol-generating procedures or in cohort wards with large numbers of COVID-19 patients.

To determine the impact of known observers on hand hygiene performance in inpatient care units with differing baseline levels of hand hygiene compliance.

Observational study.

Three inpatient care units, selected on the basis of past hand hygiene performance, in a hospital where hand hygiene observation and feedback are routine.

Three infection control practitioners (ICPs) and a student intern observed hospital staff.

Beginning in late 2005, the 3 ICPs, who were well known to the hospital staff, performed frequent, regular observations of hand hygiene in all 3 inpatient care units of the hospital, as part of routine surveillance. During the study period (January-May 2007), a student intern who was unknown to the hospital staff also performed observations of hand hygiene in the 3 inpatient care units. The rates of hand hygiene compliance observed by the 3 ICPs were compared with those observed by the student intern.

The 3 ICPs observed 332 opportunities for hand hygiene during 15 observation periods, and the student intern observed 355 opportunities during 19 observation periods. The overall rate of hand hygiene compliance observed by the ICPs was 65% (ie, in 215 of the 332 opportunities, the performance of proper hand hygiene by hospital staff was observed), and the overall rate of hand hygiene compliance observed by the student intern was 58% (ie, in 207 of the 355 opportunities, the performance of proper hand hygiene by hospital staff was observed) (P = .1). Both the ICPs and the student intern were able to distinguish between inpatient care units with a high rate of hand hygiene compliance (hereafter referred to as high-performing units) and those with a low rate (hereafter referred to as low-performing units). However, in the 2 high-performing units, the ICPs observed significantly higher compliance rates than did the student intern, whereas in the low-performing unit, both the ICPs and the student intern measured similarly low rates of hand hygiene compliance.

Recognized observers are associated with higher rates of hand hygiene compliance, even in a healthcare setting where such observations have become routine. This effect (ie, the Hawthorne effect) is more pronounced in high-performing units and insignificant in low-performing units. The use of unrecognized observers may be important for verifying high performance but is probably unnecessary for documenting poor performance. Moreover, the Hawthorne effect may be a useful tool for sustaining and improving hand hygiene compliance.

To estimate the cost of healthcare-associated infections (HAIs) in a network of 28 community hospitals and to compare this sum to the amount budgeted for infection control programs at each institution and for the entire network.

We reviewed literature published since 1985 to estimate costs for specific HAIs. Using these estimates, we determined the costs attributable to specific HAIs in a network of 28 hospitals during a 1-year period (January 1 through December 31, 2004). Cost-saving models based on reductions in HAIs were calculated.

Twenty-eight community hospitals in the southeastern region of the United States.

The weight-adjusted mean cost estimates for HAIs were $25,072 per episode of ventilator-associated pneumonia, $23,242 per nosocomial blood stream infection, $10,443 per surgical site infection, and $758 per catheter-associated urinary tract infection. The median annual cost of HAIs per hospital was $594,683 (interquartile range [IQR], $299,057-$l,287,499). The total annual cost of HAIs for the 28 hospitals was greater than $26 million. Hospitals budgeted a median of $129,000 (IQR, $92,500-$200,000) for infection control; the median annual cost of HAIs was 4.6 (IQR, 3.4-8.0) times the amount budgeted for infection control. An annual reduction in HAIs of 25% could save each hospital a median of $148,667 (IQR, $74,763-$296,861) and could save the group of hospitals more than $6.5 million.

The economic cost of HAIs in our group of 28 study hospitals was enormous. In the modern age of infection control and patient safety, the cost-control ratio will become the key component of successful infection control programs.

To describe the epidemiology of carbapenem-resistant Enterobacteriaceae (CRE) carriage and acquisition among hospitalized patients in an area of CRE endemicity.

Cohort study with a nested case-control study.

Two acute care, academic hospitals in New York City.

All patients admitted to 7 study units, including intensive care, medical-surgical, and acute rehabilitation units.

Perianal samples were collected from patients at admission and weekly thereafter to detect asymptomatic gastrointestinal carriage of CRE. A nested case-control study was performed to identify factors associated with CRE acquisition. Case patients were those who acquired CRE during a single hospitalization. Control subjects had no microbiologic evidence of CRE and at least 1 negative surveillance sample. Clinical data were abstracted from the medical record.

The prevalence of CRE in the study population was 5.4% (306 of 5,676 patients), and 104 patients met the case definition of acquisition during a single hospital stay. Mechanical ventilation (odds ratio [OR], 11.5), pulmonary disease (OR, 5.2), days of antibiotic therapy (OR, 1.04), and CRE colonization pressure (OR, 1.15) were independently associated with CRE acquisition. Pulsed-field gel electrophoresis analysis identified 87% of tested Klebsiella pneumoniae isolates as sharing related patterns (greater than 78% similarity), which suggests clonal transmission within and between the study hospitals.

Critical illness and underlying medical conditions, CRE colonization pressure, and antimicrobial exposure are important risk factors for CRE acquisition. Adherence to infection control practices and antimicrobial stewardship appear to be critical components of a CRE control program.

The epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) is changing, with USA300 emerging first in community and then in healthcare settings. We performed nationwide surveillance to assess recent trends in the molecular epidemiology of MRSA.

One hundred consecutive unique clinically significant S. aureus isolates were recovered from patients at each of 43 US centers between July 1, 2011, and December 31, 2011. Susceptibility testing, pulsed-field gel electrophoresis (PFGE), staphylococcal protein A gene (spa) and staphylococcal cassette chromosome mec typing, and Panton-Valentine leukocidin detection were performed on all MRSA isolates.

Of 4,131 isolates collected, 2,093 (51%) were MRSA. Specimen sources of MRSA isolates included wound or abscess (54%), blood (24%), lower respiratory tract (11%), and other sterile site (10%). Thirty percent were isolated more than 48 hours after hospital admission (ie, were associated with nosocomial acquisition of infection). USA300 was the most common PFGE type (1,269 isolates; 61%), overall and in all regions, followed by USA100 (368 isolates; 18%). Among 173 spa types found, the most common were t008 (51%) and t002 (18%); no other spa type accounted for more than 2% of isolates. One strain type (USA300/t008/IV) constituted almost half of all MRSA isolates (1,005 isolates; 48%) and was the most common at all body sites, causing 37% of MRSA bloodstream infections (BSIs) and 38% of nosocomial MRSA infections. Multidrug-resistant phenotypes were found among 34 USA300 isolates (3%) from 18 states.

The USA300 PFGE type continues to advance nationwide. A single strain type (USA300/t008/IV) predominates in all regions and infection sites and is now more common than USA 100 as a cause of MRSA BSI and nosocomial infections. Although most USA300 retain typical susceptibility profiles, multidrug-resistant phenotypes are emerging.

To identify risk factors for vancomycin resistance and mortality in enterococcal bacteremia.

Historical cohort study.

A large academic medical center with a high prevalence of vancomycin-resistant enterococci (VRE).

Two hundred sixty patients with enterococcal bacteremia, of whom 72 (28%) had VRE.

Independent risk factors for infection with VRE were the mean number of antibiotic days (P<.001), renal insufficiency (P<.001), mean days of vancomycin use (P=.005), and neutropenia (P=.013). A trend toward a significant association between metronidazole use and VRE also was noted (P=.068). Mortality was attributable to the bacteremia in 96 patients (37%). Severity of illness (P<.001) and age (P=.020) were independent risk factors for mortality. Vancomycin resistance was not, however, an independent predictor of mortality.

These results suggest that restrictions on antibiotic use, particularly in patients with renal insufficiency and neutropenia, may help to combat the rising incidence of VRE. Although patients with VRE bacteremia demonstrated higher mortality rates than patients with infection due to susceptible isolates, vancomycin resistance was not an independent predictor of mortality in these patients and likely serves more as a marker of underlying severity of illness.

There are limited data from prospective studies to indicate whether improvement in hand hygiene associated with the use of alcohol-based hand hygiene products results in improved patient outcomes.

A 2-year, prospective, controlled, cross-over trial of alcohol-based hand gel.

The study was conducted in 2 medical-surgical ICUs for adults, each with 12 beds, from August 2001 to September 2003 at a university-associated, tertiary care teaching hospital.

An alcohol-based hand gel was provided in one critical care unit and not provided in the other. After 1 year, the assignment was reversed. The hand hygiene adherence rate and the incidence of nosocomial infection were monitored. Samples for culture were obtained from nurses' hands every 2 months.

During 17,994 minutes of observation, which included 3,678 opportunities for hand hygiene, adherence rates improved dramatically after the introduction of hand gel, increasing from 37% to 68% in one unit and from 38% to 69% in the other unit (P < .001). Improvement was observed among all groups of healthcare workers. Hand hygiene rates were better at higher workloads when hand gel was available in the unit (P = .02). No substantial change in the rates of device-associated infection, infection due to multidrug-resistant pathogens, or infection due to Clostridium difficile was observed. Culture of samples from the hands of nursing staff revealed that an increased number of microbes and an increased number of microbe species was associated with longer fingernails (ie, more than 2 mm long), the wearing of rings, and/or lack of access to hand gel.

The introduction of alcohol-based gel resulted in a significant and sustained improvement in the rate of hand hygiene adherence. Fingernail length greater than 2 mm, wearing rings, and lack of access to hand gel were associated with increased microbial carriage on the hands. This improvement in the hand hygiene adherence rate was not associated with detectable changes in the incidence of healthcare-associated infection.

Most research on hospital falls has focused on predictors of falling, whereas less is known about predictors of serious fall-related injury. Our objectives were to characterize inpatients who fall and to determine predictors of serious fall-related injury.

We performed a retrospective observational study of 1,082 patients who fell (1,235 falls) during January 2001 to June 2002 at an urban academic hospital. Multivariate analysis of potential risk factors for serious fall-related injury (vs no or minor injury) included in the hospital's adverse event reporting database was conducted with logistic regression to calculate adjusted odds ratios (aORs) with 95% confidence intervals (CI95).

The median age of patients who fell was 62 years (interquartile range, 49-77 years), 50% were women, and 20% were confused. The hospital fall rate was 3.1 falls per 1,000 patient-days, which varied by service from 0.86 (women and infants) to 6.36 (oncology). Some (6.1%) of the falls resulted in serious injury, ranging by service from 3.1% (women and infants) to 10.9% (psychiatry). The most common serious fall-related injuries were bleeding or laceration (53.6%), fracture or dislocation (15.9%), and hematoma or contusion (13%). Patients 75 years or older (aOR, 3.2; CI95, 1.3-8.1) and those on the geriatric psychiatry floor (aOR, 2.8; CI95,1.3-6.0) were more likely to sustain serious fall-related injuries.

There is considerable variation in fall rates and fall-related injury percentages by service. More detailed studies should be conducted by floor or service to identify predictors of serious fall-related injury so that targeted interventions can be developed to reduce them.

To evaluate the effects of a hand hygiene program on compliance with hand hygiene and the rate of nosocomial infections in a neonatal intensive care unit (NICU).

Open trial.

A level-III NICU in a teaching hospital.

Nurses, physicians, and other healthcare workers in the NICU.

A multimodal campaign for hand hygiene promotion was conducted beginning in September 1998. This program consisted of formal lectures, written instructions and posted reminders regarding hand hygiene and proper handwashing techniques, covert observation, financial incentives, and regular group feedback on compliance. Surveillance of handwashing compliance and nosocomial infections before and during the program was analyzed.

Overall compliance with hand hygiene improved from 43% at baseline to 80% during the promotion program. The rate of nosocomial infections decreased from 15.13 to 10.69 per 1,000 patient-days (P = .003) with improved handwashing compliance. In particular, respiratory tract infections decreased from 3.35 to 1.06 per 1,000 patient-days during the handwashing campaign (P = .002). Furthermore, the correlation between nosocomial infection of the respiratory tract and handwashing compliance also reached statistical significance (r = -0.385; P = .014).

Improved compliance with handwashing was associated with a significant decrease in overall rates of nosocomial infection and respiratory infections in particular. Washing hands is a simple, economical, and effective method for preventing nosocomial infections in the NICU

To evaluate whether surgical site infection (SSI) rates decrease in surgical departments as a result of performing active SSI surveillance.

Retrospective multiple logistic regression analyses.

A group of 130 surgical departments of German hospitals participating in the Krankenhaus Infektions Surveillance System (KISS).

Data for 19 categories of operative procedures performed between January 1997 and June 2004 were included (119,114 operations). Active SSI surveillance was performed according to National Nosocomial Infections Surveillance system (NNIS) methods and definitions. Departments' SSI rates were calculated individually for each year of surveillance and for each operative procedure category, taking into account when the individual departments had begun their surveillance activities. Multiple logistic regression analyses on a single operation basis were carried out with stepwise variable selection to predict outcomes for patients with SSI. The variables included were as follows: the department's year of participation, NNIS risk index variables, patients' age and sex, and the hospitals' structural characteristics, such as yearly operation frequency, number of beds, and academic status.

For 14 of 19 operative procedure categories analyzed, there was a tendency toward lower SSI rates that was associated with increasing duration of SSI surveillance. In multiple logistic regression analyses of pooled data for all operative procedures, the departments' participation in the surveillance system was a significant independent protective factor. Compared with the surveillance year 1, the SSI risk decreased in year 2 (odds ratio, 0.84; 95% confidence interval, 0.77-0.93) and in year 3 (odds ratio, 0.75; 95% confidence interval, 0.68-0.82), and there was no change in year 4.

The SSI incidence was reduced by one quarter as a result of the surveillance-induced infection control efforts, which indicates the usefulness of a voluntary surveillance system.

Recent outbreaks of severe cases of Clostridium difficile-associated diarrhea (CDAD) reported in North America, the United Kingdom, and The Netherlands have emphasized the importance of an ongoing epidemiological surveillance of CDAD.

To determine the epidemiology of CDAD over the years 2000-2004 and the rate of nosocomial transmission of C. difficile.

Retrospective survey of inpatients with CDAD and molecular characterization of the strains isolated.

A 760-bed teaching hospital.

All CDAD cases diagnosed from January 1, 2000, to December 31, 2004, were reviewed. A CDAD case was defined as diarrhea in a hospitalized patient who had a stool specimen that tested positive for C. difficile cytotoxin or had a positive toxigenic culture result. CDAD was considered to be severe if a patient fulfilled at least 1 of the following 3 criteria: (1) presence of a fever (defined as temperature higher than 38.5°C), abdominal pain, and leukocyte count greater than 10,000 cells/mm3; (2) endoscopically or histologically proven pseudomembranous colitis; or (3) complications (defined as death with C. difficile infection as the primary or a contributing cause, toxic megacolon, perforation, toxic shock, and/or colectomy). CDAD was considered community-acquired if the diarrhea occurred in the patient within 72 hours after admission and if the patient had no history of hospitalization in the previous month; otherwise, CDAD was considered healthcare-associated. All the strains isolated were serogrouped and were characterized by toxinotyping and PCR ribotyping. Detection of toxin A, toxin B, and binary toxin was performed by PCR.

One hundred fifty-one cases of CDAD were diagnosed; 147 clinical records could be reviewed, and 131 strains were studied. The overall incidence of CDAD was 1.1 cases per 1,000 patients admitted, but incidence rates were higher in 2003-2004, compared with 2000-2002 (P = .017). Diarrhea was community acquired in 28 patients (19%). For patients with healthcare-associated CDAD, transmission of the strain from patient to patient (ie, infection with a strain of the same serogroup and PCR ribotype as the strain isolated from another patient hospitalized in the same ward or in a linked ward in the previous 2 months) was demonstrated in 12 cases (10.1%). Eleven percent of strains were positive for binary toxin. Binary toxin-positive strains were associated with more-severe diarrhea (P = .01 ) and with a higher case-fatality rate (P = .03). A specific clone of C. difficile (serogroup H, PCR ribotype sa026) accounted for 35 (26.7%) of all the strains isolated, but this clone was found both in healthcare-associated and community-acquired cases. Three strains belonged to toxinotype III, but only 1 was related to the hypervirulent clone involved in recent outbreaks.

The incidence of CDAD is low in our hospital, and cross-infection is limited. These results also suggest that strains with binary toxin might be more virulent.

Central venous catheter (CVC)-related bloodstream infections (BSIs) are known to increase rates of morbidity and mortality in both inpatients and outpatients, including hematology-oncology patients and those undergoing hemodialysis or home infusion therapy. Biofilm-associated organisms on the lumens of these catheters have reduced susceptibility to antimicrobial chemotherapy. This study tested the efficacy of tetrasodium EDTA as a catheter lock solution on biofilms of several clinically relevant microorganisms.

Biofilms of Staphylococcus epidermidis, methicillin-resistant S. aureus, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Candida albicans were grown to levels of approximately 1 × 105 colony-forming units (CFU)/cm−1 on CVC segments in a model system, then subjected to the tetrasodium EDTA lock treatment.

Comparisons of biofilms before and after exposure to the 40-mg/mL−1 tetrasodium EDTA lock for 21 hours showed that the biofilm viable cell counts of all organisms tested were significantly reduced (P < .05) after exposure to the treatment.

Antimicrobial lock treatment using 40 mg/mL−1 of tetrasodium EDTA for at least 21 hours could significantly reduce or potentially eradicate CVC-associated bio-films of clinically relevant microorganisms (Infect Control Hosp Epidemiol 2005;26:515-519).

Coagulase-negative staphylococci are both an important cause of nosocomial bloodstream infections and the most common contaminants of blood cultures. Judging the clinical significance of coagulase-negative staphylococci is vital but often difficult and can have a profound impact on an institution's bloodstream infection rates. Our objective was to develop an algorithm to assist in determining the clinical significance of coagulase-negative staphylococci.

A single experienced reviewer examined the medical records of 960 consecutive patients with positive blood cultures in a tertiary-care referral teaching hospital. Four hundred five of the cultures contained coagulase-negative staphylococci. A determination of clinical significance was made and the performances of various published algorithms that contained readily available clinical and laboratory data were compared.

Eighty-nine (22%) of the episodes were considered significant, whereas 316 were contaminants. Patients with bacteremia were significantly more likely to be neutropenic and exhibit signs of sepsis syndrome. The algorithm with the best combined sensitivity (62%) and specificity (91%) for determining the clinical significance of coagulase-negative staphylococci was defined as at least two blood cultures positive for coagulase-negative staphylococci within 5 days, or one positive blood culture plus clinical evidence of infection, which includes abnormal white blood cell count and temperature or blood pressure.

Use of this algorithm could potentially reduce misclassification of nosocomial bloodstream infections and inappropriate use of vancomycin for positive blood cultures likely to represent contamination (Infect Control Hosp Epidemiol 2005;26:559-566).

To analyze infectious complications that occur in patients who receive extracorporeal membrane oxygenation (ECMO), associated risk factors, and consequences on patient outcome.

Retrospective observational survey from 2005 through 2011.

Patients who required ECMO in an Australian referral center.

Cases of bloodstream infection (BSI), catheter-associated urinary tract infection (CAUTI), and ventilator-associated pneumonia (YAP) that occurred in patients who received ECMO were analyzed.

A total of 146 ECMO procedures were performed for more than 48 hours in 139 patients, and 36 patients had a total of 46 infections (30.1 infectious episodes per 1,000 days of ECMO). They included 24 cases of BSI, 6 of them secondary to VAP; 23 cases of VAP; and 5 cases of CAUTI. The most frequent pathogens were Enterobacteriaceae (found in 16 of 46 cases), and Candida was the most common cause of BSI (in 9 of 24 cases). The Sequential Organ Failure Assessment score before ECMO initiation and the number of days of support were independenuy associated with a risk of BSI, with odds ratios of 1.23 (95% confidence interval [CI], 1.03-1.47; P = .019) and 1.08(95% CI, 1.03-1.19]; P = .006), respectively. Infected patients did not have a significantly higher mortality compared with uninfected patients (41.7% vs 32%; P = .315), but intensive care unit length of stay (16 days [interquartile range, 8-26 days] vs 11 days [IQR, 4-19 days]; P = .012) and hospital length of stay (33.5 days [interquartile range, 15.5-55.5] vs 24 days [interquartile range, 9-42 days]; P = .029) were longer.

The probability of infection increased with the duration of support and the severity of illness before initiation of ECMO. Infections affected length of stay but did not have an impact on mortality.

To determine the prevalence and risk factors for nosocomial infections (NIs) in four Swiss university hospitals.

A 1-week period-prevalence survey conducted in May 1996 in medical, surgical, and intensive-care wards of four Swiss university hospitals (900-1,500 beds). Centers for Disease Control and Prevention definitions were used, except that asymptomatic bacteriuria was not categorized as NI. Study variables included patient demographics, primary diagnosis, comorbidities, exposure to medical and surgical risk factors, and use of antimicrobials. Risk factors for NIs were determined using logistic regression with adjustment for length of hospital stay, study center, device use, and patients' comorbidities.

176 NI were recorded in 156 of 1,349 screened patients (11.6%; interhospital range, 9.8%-13.5%). The most frequent NI was surgical-site infection (53; 30%), followed by urinary tract infection (39; 22%), lower respiratory tract infection (27; 15%), and bloodstream infection (23; 13%). Prevalence of NI was higher in critical-care units (25%) than in medical (9%) and surgical wards (12%). Overall, 65% of NIs were culture-proven; the leading pathogens were Enterobacteriaceae (44; 28%), Staphylococcus aureus (20; 13%), Pseudomonas aeruginosa (17; 11%), and Candida species (16; 10%). Independent risk factors for NI were central venous catheter (CVC) use (odds ratio [OR], 3.35; 95% confidence interval [CI95], 2.91-3.80), admission to intensive care (OR, 1.75; CI95, 1.30-2.21), emergency admission (OR, 1.57; CI95, 1.15-2.00), impaired functional status (Karnofsky index 1-4: OR, 2.56; CI95, 1.95-3.17), and McCabe classification of ultimately fatal (OR, 2.50; CI95, 2.04-2.96) or rapidly fatal (OR 2.25; CI95,1.52-2.98) underlying condition.

According to the results of this survey, NIs are frequent in Swiss university hospitals. This investigation confirms the importance of CVCs as a major risk factor for NI. Patient comorbidities must be taken into account to adjust for case mix in any study comparing interhospital or intrahospital infection rates.