Since extended spectrum β-lactamase (ESBL) genes are located on a plasmid, transmission of ESBL genes might be possible beyond bacterial species. Therefore, resistant bacteria with ESBL genes might spread quickly and cause serious nosocomial infections. The outbreak of ESBL-producing Klebsiella oxytoca was detected in the neurosurgery ward of our hospital. Analysis using pulsed-field gel electrophoresis (PFGE) revealed horizontal transmission of only one strain. Since only reinforced hand hygiene was not effective to control the outbreak, we performed not only reinforced contact precautions but also education for medical staff and active screening for patients and medical staff, and isolation of patients. Such measures could lead to reduction of the outbreak. We considered that delay in aggressive intervention by the ICT would be associated with longer duration of the outbreak. We conclude that ICT intervention from the early stage and aggressive isolation strategy are necessary to control outbreaks of ESBL-producing bacteria.

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  We have reported an accuracy of 73% using cluster analysis on drug sensitivity using the SPSS^TM (Method S) compared to genotyping for methicillin-resistant Staphylococcus aureus (MRSA). Here we studied the efficacy of cluster analysis using Excel^TM with free additional software (Method E) on multi-drug susceptibility compared to Method S. Subjects were MRSA strains first isolated in an individual. Cluster analysis was performed in (1) 71 strains using the same 11 drugs used in our previous study, (2) 70 strains using 15 drugs for the 2011 series, and (3) 70 strains using 13 drugs for the 2005 series suspected of cross infection. (1) Method E typed completely as did Method S. (2) Method E showed sensitivity, specificity, and accuracy of 97.6%, 92.9%, and 95.7% compared to Method S. (3) Method S typed four strains in one cluster separately from those of hospital personnel, indicating cross propagation rather than transmission via the staff. Hand-to-hand infection control was enforced with success. Method E showed identical typing with Method S. Methods E and S allowed typing in about three days. Therefore, typing using Method E may have advantages in analyzing MRSA cross infection, enabling rapid intervention.

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  We evaluated the disinfectant activity of sodium hypochlorite on Clostridium difficile spores attached to four types of test material (melamine resin, ceramic tile, polypropylene, and stainless steel). In the absence of albumin, the sporicidal effects of wiping with 0.02–0.05% (200–500 ppm) solutions were weak, but spores were killed within 30 min after wiping with 0.1% solution (1,000 ppm) and within 5 min after wiping with 0.5% (5,000 ppm) solution. In the presence of 0.1% albumin, spores were killed within 60 min after wiping with 0.1% solution and within 5 min after wiping with 0.5% solution. Wiping with 0.1–0.5% sodium hypochlorite is therefore effective for disinfecting environments contaminated with C. difficile spores.

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  Five outbreaks of gastroenteritis caused by norovirus occurred in our hospital in 2007, and we had to restrict admission of new patients to the affected wards to terminate the outbreaks. Isolation of the proband of gastroenteritis from the ward took two to five days in every outbreak. Assuming that rapid isolation of the proband of gastroenteritis from the ward would be helpful to prevent gastroenteritis outbreaks, we have since tried to discover and isolate patients suffering from infectious gastroenteritis as quickly as possible. Consequently, the number of gastroenteritis outbreaks decreased to one in 2008, one in 2009, and zero in 2010. To investigate the risks of gastroenteritis outbreaks in the wards, 168 cases (85 inpatients and 83 healthcare workers) of gastroenteritis reported to the infection control team between April 2006 and March 2009 were analyzed. Sixty-four inpatients suffering from infectious gastroenteritis were isolated from the ward on the day of onset, and no gastroenteritis outbreaks subsequently occurred. Eleven inpatients suffering from infectious gastroenteritis were isolated from the ward on the day after onset, and one gastroenteritis outbreak subsequently occurred. Five inpatients suffering from infectious gastroenteritis were isolated from the ward on the second day after onset, and two gastroenteritis outbreaks subsequently occurred. Five inpatients suffering from infectious gastroenteritis were isolated from the ward on the third to fifth day after onset, and five gastroenteritis outbreaks subsequently occurred. Eighty-one of the 83 healthcare workers suffering from infectious gastroenteritis were isolated from the ward by the second day after onset, and no subsequent gastroenteritis outbreak occurred. From these observations, we emphasize the importance of early discovery and isolation of patients suffering from infectious gastroenteritis from the ward to prevent nosocomial outbreaks of norovirus infection.

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  Several electric devices are sold in the market by famous electric companies in Japan which are advertised to have effective properties for inactivating airborne viruses and bacteria. If such claims were realistic and reliable, these devices would be useful for infection control in many settings. However, no scientific reports which passed the process of impartial and strict peer review have investigated such claims. Therefore, we tried to evaluate the bactericidal effects of some devices. The devices examined were the “Plasmacluster ioniser” of Sharp Co, Japan, “Nano-e generator”of Panasonic Co, Japan, and “Eneloop Air-fresher” of Sanyo Co, Japan. Bactericidal effects were tested using S. aureus, P. aeruginosa, B. cereus, and E. faecalis as follows: two small droplets of 1 μL each, containing a certain amount of each bacterium were put onto a glass slide and smeared. The slides were kept in a closed glove box of 0.2 m³ inner volume, and one of the devices was operated in the box for a given length of time. Glass slides not exposed to any device were used as controls. Each glass slide was retrieved from the box and the smear on the slide was washed out with 1 mL of culture medium. The medium was collected and the amount of living bacterium was titrated by the pour-plate-culture method. There was no significant difference in the amount of bacteria from the slides exposed with the devices compared with the controls, for all bacteria tested and all devices examined. These results strongly suggest that such devices have almost no bactericidal effect, at least on the bacteria under the conditions used in the study.

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  With respect to infection control education, our hospital lacked a systematic training program intended for our entire staff. General information on preventive measures against infections was mainly covered in group education programs held twice a year, offering limited infection control education. Therefore, to initiate changes in our behavior towards infection prevention, we began an infection prevention training program in 2008 using the clinical ladder system focusing on issues in our practice. However, due to insufficient clarification of these issues and effective solutions within each department, the program changed the behaviors of only some nurses, while failing to change the collective behavior of our entire nursing staff. Thus, the program still left us with the challenge of how to continue carrying out infection preventive measures consistently. This led us to consider and adopt another infection prevention training program using the clinical ladder system; in this program, the focus was placed on the progress of changes in the views and behaviors of nurses towards infection prevention. As a result, measures drawn up to resolve issues within each department could be successfully put into action, and changes eventually took place in the collective behavior of our entire nursing staff. Based on this outcome, we found that this training program using the clinical ladder system to evaluate behavioral changes in nurses towards issues in their practice could bring about changes in the collective behavior of the entire nursing staff. The system is thus useful in implementing practical and effective preventive measures against infections.

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  Acquisition of tetanus immunity is expected to occur in all people. Induction of tetanus immunity is desirable as a precaution after a bite or disaster activity from a patient in healthcare workers. Tetanus toxoid inoculation program was carried out for our staff. Individuals born before April 1968, when the diphtheria, pertussis, and tetanus (DPT) vaccination was introduced, were given three inoculations of tetanus toxoid. Individuals born after April 1968 were given one inoculation, and individuals who could not remember previous DPT vaccination were given three inoculations, if requested. Immunization coverage in this program was 74.3% (754/1021), which seemed to be high regardless of occupational groups. In the first day of the program, half of our entire staff were given tetanus toxoid. Immunization coverage rate by age was about 30% in the twenties and thirties group; 17% in the forties and fifties group, and 3% in the sixties group. The coverage rate was 92.8% (285/307) in all staff aged more than 40s including a person born before DPT commuter pass inoculation start. The coverage rate was 65.7% (469/714) in staff aged less than 30s born after DPT vaccine commuter pass inoculation. Adverse reactions of local redness and swelling were observed frequently without severe reaction. Acquisition of tetanus immunity is strongly recognized as useful in hospital personnel, resulting in such a high inoculation rate.

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