The number of needlestick injuries in healthcare workers has been declining due to education on the prohibition of recapping and popularization of safety devices; however, the number of needlestick injuries with pen needles is still increasing. We investigated the numbers of needlestick injuries with pen needles in three hospitals to assess the effect of introducing safety-engineered pen needles for insulin injection. Many cases of needlestick injuries with pen needles occur during the process of recapping or disposal. The number of needlestick injuries per month decreased from 0.33 to 0.20 cases per month with the introduction of safety pen needles. The results suggest that the introduction of safety pen needles secures a safe working environment for health care workers.

A comparative investigation on the disinfection effects of rinsing and water discharge on the surface of the washing nozzles of toilet seats with warm-water washing functions was performed using standard tap water and hypochlorous acid water produced by the electrolysis of tap water. When rinsing and water discharge using tap water were performed five times consecutively on washing nozzles where approximately10⁵-10⁶ cfu/mL of Escherichia coli and Pseudomonas aeruginosa had been deposited, the quantity of deposited bacteria fell by four orders of magnitude. Rinsing with hypochlorous acid water containing 1.5 ppm of hypochlorous acid resulted in the quantities of both E. coli and P. aeruginosa falling below the detection limit from the third rinse, with the bacteria on the nozzle surface falling below the detection limit as well. It is therefore suggested that hypochlorous acid is more effective than tap water as a cleaning fluid to maintain the sanitary nozzle conditions. However, even rinsing with hypochlorous acid water was not able to achieve 100% disinfection from P. aeruginosa; therefore, it is believed that consideration must be given to the target users and locations of use.

Reliability of a commercially available chemical product sold in Japan that has been claimed to inactivate viruses and kill bacteria on the environmental surface by releasing chlorine dioxide gas was investigated.

The aliquots of the viral fluid of influenza A/Aichi/2/68 strain virus propagated in the allantoic fluid of fertilized hens' eggs and the bacterial fluid of Staphylococcus aureus stock solution were poured on a glass slide as two and four droplets of 0.5 μL each, respectively, and placed in a 25 m³-space closed environment, with the temperature and relative humidity set at about 20°C and 25%, respectively, which resemble room conditions during the winter season. The concentration of the gas was manually adjusted at about 0.03 ppm by opening and closing the bottle cap. After 2 h, the dried-up remains of the droplets on the glass were washed out with 1 mL of viral culture medium or bacterial broth, and the amounts of the active virus and the living bacteria in the washing fluid were titrated using plaque or colony assays, respectively. The amounts of the active viruses and living bacteria were similar in the washing fluids from both the gas-exposed and the control slides, indicating that the gas had no virucidal and bactericidal activities under these conditions.

Although international efforts to standardize metrics for monitoring methicillin-resistant Staphylococcus aureus (MRSA) in healthcare settings are in progress, the national MRSA benchmark data is still lacking in Japan. We measured two MRSA surveillance indices at seven tertiary care hospitals, based on the Multidrug-Resistant Organism & Clostridium difficile Infection Module published by the Centers for Disease Control and Prevention. During the 1-year study period, the MRSA infection or colonization incidence rate was 0.26 per 1,000 patient-days, whereas the MRSA bloodstream infection incidence rate was 0.04 per 1,000 patient-days. The 30-day all-cause mortality rate per 100 MRSA bacteremia cases was 20.3%. As the National Action Plan on Antimicrobial Resistance is launched, we believe this study provides a reference regarding MRSA incidence in Japanese healthcare settings.

Although hepatitis B virus (HBV) vaccine shows protective effect against HBV infection, its efficacy when manufactures derived from different antigens (MDA) were used in subsequent doses after the primary series remained unclear.

HBV vaccine of MDA was inoculated in nine health-care workers with both negative hepatitis B surface (HBs) and HBs antibody at the third dose. We then evaluated the immunogenicity.

All participants showed successful seroconversion of anti-HBs antigen to seropositive after 10 months. Adverse events with grade 1 were found in 33% (3/9) and were permissive.

In conclusion, our results suggested that vaccination for HBV was successful even when MDA was used at the third dose for HBV.

The wide spread of drug resistant organisms due to inappropriate use of antibiotics is a global emergent problem, and appropriate antibiotic use is required. Although there have been many reports that the introduction of Antimicrobial Stewardship Program (ASP), a hospital based intervention designed to improve antibiotics prescription and minimize unnecessary costs, is effective against inappropriate use of antibiotics, the effect of ASP in Japanese childrens' hospitals remains unclear. In Nagano Children's Hospital, our infection control team (ICT) has challenged appropriate antibiotic use in our institute; however, we have failed to obtain expected results. Our ASP employed a prospective audit and feedback about the antibiotic prescription, but our strategy lacked a system allowing consultation on antibiotic prescription and infectious diseases. Therefore, we introduced the consultation system in 2012, although our hospital did not have a department for infectious diseases. Our consultants consisted of ICT staffs.

In this study, we retrospectively assessed the impact of our intervention. Our ASP was assessed between September 2010 and March 2016. This interval was divided into two phases: Phase 1, before intervention period and Phase 2, after intervention period. In our hospital, days of therapy (per 1000 patient-days) of meropenem significantly decreased from 13.6 to 6.5 (p=0.02). In addition, antimicrobial susceptibility of Pseudomonas aeruginosa against meropenem improved from the lowest level of 79% in 2013 to 88% in 2015. On the other hand, no change was observed in all-cause and infection-related mortalities between the phases. After the implementation of ASP in our hospital, we could safely decrease the prescription of antibiotics. In addition, the antibiotic resistance of Pseudomonas aeruginosa improved after our intervention.