The National Nosocomial Infections Surveillance (NNIS) system was established in 1970 by the Centers for Disease Control and Prevention of the United States. As the world's first surveillance system for healthcare associated infections, experience has resulted in gradual changes over time. The NNIS transitioned to the National Healthcare Safety Network (NHSN) in 2006. Numerous surveillance components were added in this process. The number of participating hospitals increased sharply, and the amount of collected data now allows use as a benchmark for individual hospitals. On the other hand, the system changes the surveillance definition of infections very frequently. In addition, the public reporting policy which was implemented in many of the states in the late 2000s seemed to reduce the quality of the data, with apparently low infection rates in both device-associated infections and surgical site infections. The present study overviews the development of the world's biggest infection surveillance systems, the NNIS and NHSN, to clarify the direction of the national surveillance system.
In 2013, the Centers for Disease Control and Prevention (CDC) replaced the national surveillance definition for ventilator-associated pneumonia (VAP) in adult inpatient settings with definitions for ventilator-associated events (VAEs). Since the inception of VAE surveillance, several modifications have been made to improve methods and definitions. Multiple studies have confirmed VAE epidemiology, correlation of VAE with VAP surveillance, risk factors, and strategies to prevent VAEs. This article updates the changes in VAE definitions and reviews the current published studies on VAE.
Sodium hypochlorite has been widely used as an effective disinfectant, but involves possible hazards to health. Chlorous acid water is considered less hazardous compared with sodium hypochlorite. The bactericidal and virucidal effects of chlorous acid water were evaluated using suspensions of Escherichia coli (E.coli) and feline calicivirus (FCV). In general, the activities of disinfectants might be affected by the presence of organic substances such as bovine serum albumin (BSA). Higher BSA concentration requires greater free available chlorine ion concentration for inactivating E.coli and FCV, but chlorous acid water clearly inactivated both E.coli and FCV. Consequently, chlorous acid water is an effective disinfectant even in the presence of organic substances. Furthermore, the presence of organic substances could reduce the effectiveness of sodium hypochlorite. The bactericidal and virucidal activities of sodium hypochlorite and chlorous acid water were evaluated in the presence of bovine serum albumin (BSA). When sodium hypochlorite was added to BSA, the concentration of free available chlorine ion declined sharply. In contrast, when chlorous acid water was added to BSA, free available chlorine ion was detected as rapidly as within 30 min and 40~70% of free available chlorine ion was retained. The bactericidal and virucidal effects of chlorous acid water and sodium hypochlorite were correlated with the concentrations of the residual free available chlorine ions. Therefore, chlorous acid water is far more effective than sodium hypochlorite as a disinfectant.
This study investigated the relationship between frequency of wiping with disinfectant and decrease in bacteria on environmental surfaces in general wards. In the surgical ward of 1 facility, the numbers of bacteria for on multiple environmental surfaces were investigated. Large numbers of living bacteria were detected on the surfaces of a toilet seat, a washing operation panel, and around the faucet in a washhand stand, located in the general ward restroom for patients. Six medical institutions participated in a study of the number of times per day for wiping with disinfectant and the decrease in bacteria in these three places. Two restrooms of each facility were divided into the A group (wiping only once a day in the morning) and the B group (wiping twice a day, morning and evening). Environmental surface wiping continued for 5 days. Specimens were gathered from the three places before wiping on the morning of the first day, second day, and fifth day, and total number of the bacteria, number of living bacteria, adenosine triphosphate (following ATP level) were measured. Wiping methods were unified in 6 facilities, with the wipe immersed in a peroxy-potassium hydrogen sulfate (oxidizer) combination agent. The numbers of living bacteria on the environmental surface of a washing operation panel, and around the faucet in a washhand stand decreased in the B group compared with the A group (p<0.05). The ATP level decreased on the environmental surface of a washing operation panel, and around the faucet in a washhand stand in the B group compared to the A group (p<0.05). The number of living bacteria around the faucet in a washhand stand did not significantly decrease just after wiping with disinfectant. On multiple investigation points of the general ward restroom, the number of living bacteria on the environmental surface were significantly decreased by increasing the frequency of wiping with disinfectant from once to twice a day.
This study tried to quantify the additional healthcare resources (indicated by length of hospital stay and healthcare expenditure) consumed by MRSA infections. The study included patients who had been discharged from our hospital (a 380–bed tertiary hospital) between December 2012 and December 2014. The database for analysis involved the combination of 2 administrative datasets: JANIS infection surveillance data for all admissions, and data from a government survey on the post-implementation effects of the diagnosis procedure combination system. The data were analyzed through propensity score matching. Propensity scores were estimated using a logistic regression model in which the independent variable was a dichotomous MRSA infection variable (1: infected; 0: uninfected). Using the propensity score, 1:1 matching was performed between cases (MRSA infection) and controls (no MRSA infection). The data was also analyzed using another matching method that addressed time-dependent bias. The additional healthcare resources associated with MRSA infections were calculated from the differences in the mean quantities of resources consumed between cases and controls. The total of 24,538 patients in the study included 47 identified as MRSA-infected patients. Including time-dependent bias, infected patients were associated with an additional length of stay of 13.1 days (95% confidence intervals [CI] 3.7–22.4, p=0.008) and an additional incremental healthcare cost of 1.07 million yen (95% CI 0.317–1.822, p=0.007). Excluding time-dependent bias, the additional length of stay was 21.2 days (95% CI 11.7–30.8, p<0.001) and the additional healthcare cost was 1.61 million yen (95% CI 0.643–2.570, p=0.001). The additional healthcare resource consumption associated with MRSA infections was estimated using propensity score matching using 2 matching methods that differed according to whether or not time-dependent bias was included. The 2 methods produced different estimates, indicating that failure to address time-dependent bias may lead to overestimates of the additional healthcare resources consumed. These estimates have possible applications in evaluating the cost-effectiveness of infection control and prevention measures.
This study was designed to establish an efficient, highly sensitive, and rapid diagnostic system based on silver amplification for influenza infection. Nasopharyngeal swabs from 629 patients were used to compare the performances of influenza diagnostic kits (manual method) and a highly sensitive influenza diagnostic system (automated method). The relationships between the test results and clinical factors were also investigated. Negative results for the manual method and positive results for the automated method tended to occur for adults up to 6 hours after the onset of fever. However, there was no relationship between a positive outcome and elapsed time of the fever in children. The 162 positive cases (both manual and automated) manifested as high fever, headache, cough, runny nose, arthralgia and muscle pain, and these symptoms were significantly worse than the 442 negative cases. Another 25 cases (manual negative and automated positive) had no significant symptoms. The 162 positive cases had only high fever worse than the 25 manual negative and automated positive cases. The results indicate that the highly sensitive system is useful for adult patients with fever of less than 6 hours duration and for children, and for patients with poorly defined high fever. These characteristics are very useful for infection control, especially in an epidemic, so we use the automated method for inpatients and staff members.
No previous investigations have assessed awareness of epidemic viral infections among nursery school teachers, countermeasures against such infections, and support of municipal hospitals for the promotion of vaccinations. The present questionnaire survey included nursery school teachers who participated in a workshop held by the infection control team (ICT) of our municipal hospital to clarify the current status of these topics. The survey revealed the insufficient recognition of personal histories of epidemic viral infections and vaccinations among the teachers. Personal antibody titers were comprehensively managed in only 15 of the target facilities. Furthermore, the frequencies of confirming nursery school student histories of vaccinations and providing vaccination-related advice for the parents of students without such histories were shown to decrease after enrolment. On the other hand, changes in the management of epidemic viral infections were observed based on a questionnaire survey performed 3 months after the workshop, confirming the usefulness of support from municipal hospitals.