Reportedly, methicillin-resistant Staphylococcus aureus (MRSA) can survive for a few weeks on surfaces in nursing environments. However, the survival of MRSA attached to different materials used in medical devices which may come into contact with inpatients, such as bedside rails, linen, and other equipment in nursing environments, has not been fully discussed. We examined the survival of Staphylococcus aureus (S. aureus) attached to different materials found in nursing environments, such as cotton and polypropylene cloth, as well as silicone rubber, copper, brass, aluminum, and stainless steel, at 5, 20, and 35°C. Among the strains attached to polypropylene cloth or aluminum or stainless steel, methicillin-sensitive S. aureus [MSSA (ATCC 29213)], MRSA (ATCC 43300), and MRSA [environmental-origin MRSA (L1)] strains isolated from nursing environments in the health-care facility survived after 30 days at 5 or 20°C. Among strains attached to cotton cloth, MSSA, MRSA, and environmental-origin MRSA (L1) survived after 15 days at 5 and 20°C, but no strains survived after 7 days at 35°C. Among strains attached to copper or brass, MSSA, MRSA, and environmental-origin MRSA (L1) survived just after attachment in suspension, but no strains survived after drying at 5, 20, or 35°C. These results suggest that the survival of MRSA depends on the attached material. Therefore, adequate disinfection and cleaning of surfaces is essential to prevent transmission of MRSA through equipment or materials in nursing environments, because MRSA may survive for more than 30 days on some metal or nonmetal materials.

View full abstract

  Negative pressure room is indispensable for controlling airborne pathogens such as measles or tuberculosis bacilli. Previously, we proposed layouts to reduce droplet nuclei in the negative pressure room, however, a problem that droplet nuclei in the negative pressure room leaked promptly to a corridor when the door was opened remained unsolved. The push-pull local exhaust has not yet been discussed as a partition of space to prevent leakage. We discussed the conditions of push-pull airflow which prevents air leakage and maintains the air pressure balance even if the door has opened. We modelled installation of a push-pull device in substitution for a door between a corridor and an anteroom. We analyzed the dynamics of droplet nuclei in the corridor and the anteroom using a Computational Fluid Dynamics (CFD) method. We evaluated the effect by counting the number of droplet nuclei in the corridor which leaked from the negative pressure room. The leakage of the droplet nuclei was small if the airflow velocity from the push device was 0.05 to 0.3 m/s, and also low if the airflow velocity to the pull device was more than 0.2 m/s. Larger width of the push-pull device resulted in lower leakage of the droplet nuclei. Wider space between the push device and the pull device also resulted in lower leakage of the droplet nuclei. In the case of the same air volume, doubling the push-pull device width was more efficient than doubling the airflow velocity. The push-pull airflow design is effective as both a local exhaust and as a space partition instead of a door.

View full abstract

  Human norovirus (HuNoV) may pose significant health risks to infants if the virus contaminates infant feed, and HuNoV infections are very important to prevent through infant feed such as breast milk. However, little is known about the appropriate condition to inactivate HuNoV, due to the lack of a routine cell culture system for HuNoV. The present study used a murine norovirus which is culturable and genetically close to HuNoV as a surrogate for HuNoV, and investigated its inactivation characteristics in breast milk. MNV inoculated in breast milk was rapidly inactivated and reached more than 99.9% (3 log₁₀) inactivation after 1 min treatment at 65°C. Our results suggest that heat treatment of more than 65°C and 1 min can adequately inactivate HuNoV in breast milk.

View full abstract

  Standard evaluation for surgical hand washing is based on the glove juice method using bacterial culture. However, this method is complicated and routine implementation is difficult. On the other hand, simple equipment to measure adenosine triphosphate (ATP) is used to evaluate the purity of medical instrumentations. The present study evaluated the use of ATP measurement for evaluation of surgical hand washing. Samples were obtained according to the modified glove juice method before and after surgical hand washing. Colony forming unit (CFU) and ATP of the samples were determined and converted to ATP or bacterial amount (BA) per one hand. There was a significant correlation between log (BA) and log (ATP). There was no correlation between BA reduction rate and ATP reduction rate. Comparing our method with the standard method, measuring time is short, operation is simple, and cost is low. If scientific evidence is established, this method is clinically useful. The BA reduction rate did not correlate with the ATP reduction rate, probably because ATPs exist in bacteria as well as in non-bacterial sweat and skin drop debris and both are measured. On the other hand, the ATP reduction rate was lower than BA reduction rate suggesting that ATP provides a more sensitive indicator. More research is required to improve this method and to consider criteria to apply this method.

View full abstract

  “Cough etiquette” is important for preventing the spread of influenza and other diseases through droplet infection. Infection can be more effectively prevented if “cough etiquette” is practiced not only at hospitals, but also at regional facilities and by the general public. This study assessed the actual awareness of “cough etiquette” among the Japanese public to obtain hints for future educational activities. Members of the general public were surveyed using the Internet twice, in February 2009 and March 2010. A total of 400 individuals were investigated in each survey, and subjects were selected by stratified sampling based on area of residence, age, and sex. Survey items included awareness of the term “cough etiquette”, practice of “cough etiquette”, and reason for wearing masks. The percentage of subjects who replied “Yes” to the question “Have you heard of the term “cough etiquette”?” was 31.0% (n=124) in the first survey and 47.8% (n=191) in the second survey. The only factors that were significantly more common among subjects who had heard of “cough etiquette” compared to those who had not were the action of “covering the nose and mouth when coughing or sneezing” in the first and the second surveys, and the response of “the presence of symptoms such as coughing or sneezing” as the most appropriate reason for wearing masks in the second survey. These results suggest that only having heard of the term “cough etiquette” does not lead to the correct behavior. Therefore, educational activities should be increased in the future through the use of media such as television and displays at hospitals.

View full abstract

  For the prevention of occupational infection, serological screening for antibodies to measles, varicella, rubella, mumps and hepatitis B was performed followed by vaccinations for the health-care workers, non-health-care workers and students in our hospital. As a result, the seropositivities to measles, varicella, and rubella increased to more than 90%, but that to mumps increased to only 80.0%. Although the seropositivity to hepatitis B among health-care workers rose to around 80%, that of the newcomer men/women and students remained relatively low, suggesting that the vaccination program at the school is insufficient. Our division can produce the antibody lists immediately because all data is stored. In the future, the problem is the follow-up for vaccination-prohibited cases and failure cases after the second vaccination.

View full abstract

  Multidrug-resistant Pseudomonas aeruginosa (MDRP) was detected in 26 patients between August 2007 and September 2009. DNA analysis of the 10 strains in 10 patients newly detected since January 2008 with pulsed-field gel electrophoresis (PFGE) revealed similar patterns in 8 of the 10 strains tested. Nine of the 10 patients had undergone continuous urinary catheterization, and the infection was probably propagated through incorrect handling and urine processing of the continuous urinary catheterization system and the bag. However, 2 strains showed no relationship, so MDRP was detected of strains other than the similar strains in the region, so carrier patients may be present, and correct use of antimicrobial agent is important. The outbreak of MDRP was resolved by the guiding ICT including a Board Certified Infection Control Pharmacy Specialist in this hospital despite the common absence of a specialist bacteriological examination room in small and medium hospitals and further infection was absent.

View full abstract

  For improvement of infection control standards in the area, institutional ICT rounds were combined with a common check list in five medical facilities, which belonged to the Nagano north demographic division of medical services. After the rounds, the ICC and the ICT members exchanged views about problems. In addition, the utility of these combination ICT rounds were evaluated using a questionnaire at the same time. As a result, the water-supply environment were identified as the area with most inadequate infection control in each institution. From the questionnaire survey, many institutions felt that hospital infection control in the institution was inadequate, and that future hospital infection control should be developed with education training, appropriate use of antimicrobial agents, round activity, and full order of facilities. The implementation of the combination ICT rounds was considered effective by 96% of the members based on infection control with regional alliances, and all members considered that participation was good. After the combination ICT rounds, some institutions achieved improvements in indicated areas. These findings show that the implementation of the combination ICT rounds was useful. The combination ICT round is a method of team medical care in an area carried out across the category of jobs and institutions, and this activity may contribute to the improvement of institutions and local infection control standards.

View full abstract