This study evaluated the decontamination of new dental chair unit water lines (DUWLs) with slightly acidic electrolyzed water (SAEW) installed in our hospital. The built-in SAEW producing device supplies SAEW (available chlorine concentration 10–30 ppm, pH 6.3–6.8) into the DUWLs during and after dental treatments. One of two high speed handpiece lines (H1) is included in the cleaning system, but the other (H2) is cleaned using tap water to compare the effects. Water samples from the H1 and H2 lines were periodically taken once a month before use. All samples were measured for available chlorine concentration and the number of CFU/mL was counted on R2A agar plates after incubation at 25℃ for 7 days. The predominant isolated bacteria were identified by analysis of 16S rRNA gene sequences. The H1 samples showed higher available chlorine concentration compared with H2 samples. Although no microbiological growth was detected from almost all H1 samples, microbiological growth was often detected from H2 samples. The dominant bacteria isolated among the heterotrophic bacteria were Methylobacterium spp. Mycobacterium spp. and Sphingomonas spp. Therefore, this study suggests that this type of cleaning system using SAEW is effective for the decontamination of DUWLs.

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  A sudden increase in cases of neonatal fever was observed at our hospital in 2009. Moreover, Bacillus cereus was detected in a large number of cultures taken from hospitalized neonates during the same period. An infection control team examined the hospital environment and revealed widespread B. cereus contamination of the linen used in the maternity ward. Therefore, the increase in cases of neonatal fever resulted from a B. cereus outbreak and antiseptic and preventative measures were implemented to halt the spread of contamination. B.cereus contamination at the company commissioned to handle the hospital's laundry was suspected to be the underlying cause of the outbreak at our hospital. Our measures resulted in the elimination of B. cereus infections in hospitalized neonates, and no new cases of neonatal fever were detected. B. cereus resides in the environment and shows resistance to antiseptics, so complete elimination from laundry is difficult. Therefore, the number of B. cereus-positive specimens in hospitals should be monitored, and if an increase in positive samples is detected, the hospital's infection control team must examine if the increase should be considered a B. cereus outbreak.

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  Antimicrobial efficacy of complex-type chlorine-based disinfectant cleaner (RST) consisting mainly of potassium peroxymonosulfate against pathogenic microorganisms such as methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant Pseudomonas aeruginosa (MDRP), feline calicivirus (FCV) as a surrogate for norovirus, and bovine viral diarrhea virus (BVDV) as a surrogate for hepatitis C virus. In the suspension test, 1% RST caused 4 log₁₀ or more reduction in MRSA, MDRP and FCV in 1 minute in the presence of 0.03% bovine serum albumin. The viral inactivation efficacy of RST was better than that of NaOCl at the same available chlorine concentration. In the immersion test using BVDV adhering to stainless carrier, the viral inactivation efficacy of 0.1% NaOCl and 1% RST in 1 minute was 0.9 log₁₀ reduction and 3.3 log₁₀ reduction, respectively. Furthermore, in the wipe test, 1% RST immersion wipes caused 4.5 log₁₀ or more reduction in FCV. The present findings suggest that RST is effective for daily disinfection and cleaning in the hospital environment.

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  Blood culture specimen collection from the intravascular indwelling catheter for the diagnosis of bloodstream infection is generally not recommended, but specimen collection from the catheter and catheter tip culture for the diagnosis of catheter-related bloodstream infection (CRBSI) is recommended. However, since actual infection and contamination for blood culture specimen collection from the intravascular indwelling catheter are difficult to discriminate, we do not know the real implementation rate in actual clinical practice. We sent a questionnaire survey on blood extraction for blood culture and catheter tip cultivation from indwelling catheters to 188 facilities in the Tokai and Hokuriku areas to assess implementation status. Answers were obtained from 114 institutes (answer recovery rate 61%). Only 54% of the institutes collected blood from the catheter. Also, one of two sets was obtained from the catheter-non-indwelling side in 52% of the institutes. Although catheter tip culture had been implemented in 98% of institutes, the culture method was different at each facility. It is important that all medical staff understand the clinical significance of blood collection from indwelling catheters. Also, educational intervention for blood culture is necessary for all medical staff.

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  No clear index is available for prophylactic antimicrobial administration during oral and maxillofacial surgery. Moreover, the correct use is little understood. Therefore, the antimicrobials used for oral and maxillofacial surgery are often empirically chosen based on the characteristics of the medical facility or the experience of the surgeon. In our department, we have recommended the prophylactic use of a first-generation cephalosporin rather than a second-generation cephalosporin since July 2011. Our first-generation cephalosporin recommendation is the result of a study conducted by the infection control team (ICT) in our hospital. To confirm whether or not this change represents appropriate use of antimicrobials, we determined the incidence of surgical site infections (SSIs) in malignant tumor cases (n=140), in which SSI occurs most frequently (4.7%) among all cases (n=1,160), and prophylactic antimicrobials were administered between January 2009 and December 2013. In this study, 3 SSI cases were found in the cefazolin (CEZ) group (4.8%), and 3 SSI cases in the cefotiam (CTM) group (4.1%). Because the incidence of SSIs in the CEZ and CTM groups did not differ, we showed that a first-generation cephalosporin can prevent SSIs during oral and maxillofacial surgery similar to a second-generation cephalosporin. The prophylactic antimicrobial dosing period and change to internal use antimicrobial, as well as other SSI risk factors, require investigation.

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  The antimicrobial stewardship program (ASP) is intended to promote the use of appropriate antimicrobial agents in consideration of bacteria and infection sites which cause various infectious diseases. Infection control software can collect information in a short period of time. We report the results of effective antibiotic appropriate use support with the software. In the first year of the 2–year period from January 2013 to December 2014, there were 81 instances of pharmacist support of antimicrobial use by physicians, which increased by 3.4 times to 272 in the second year. The contents of support were often “De-escalation”, “Proposal of the end”, “Proposal of new antimicrobial agents or change in empiric therapy”. Consultation instances totalled 43 in the first year, but increased by 4.3 times to 186 in the second year. Antimicrobial use density of tazobactam/piperacillin in the second year (TAZ/PIPC) (AUD) was significantly reduced compared to the first year, and the resistance rate for TAZ/PIPC of Pseudomonas aeruginosa also decreased significantly. These results presumably indicate that the reduction in the AUD of the TAZ/PIPC is related to decreased resistance rates of P. aeruginosa. We found that pharmacists were able to efficiently gather data in a short period of time by utilizing the infection control software and positively participated in infectious disease therapy, resulting in correct antimicrobial use by physicians.

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  Outbreak of norovirus infection must be prevented in the catering staff in large facilities, especially hospitals. A total of 370 stool samples from 62 catering staff in our hospital were checked with an antigen detection kit for norovirus, and no antigen was detected. In contrast, norovirus RNA was detected with real-time PCR in 2 of 44 stool samples from staff who had experienced vomiting and/or diarrhea within 4 weeks and was even detected after one month. The detection kit is simple and useful for making a diagnosis, but may overlook the presence of norovirus in the screening of healthy people because of sensitivity. In conclusion, we think that education for hand cleanliness is more important than screening with the antigen detection kit.

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  Automatic urine quantity measuring devices are well known to involve the risk of resistant bacteria transmission. Use of this device was discontinued during an outbreak in our hospital. Metallo-beta-lactamase positive S.maltophilia was isolated from ten patients over 10 days in November 2011. Cultivation of samples from the automatic urine quantity measuring device in that ward revealed metallo-beta-lactamase positive MDRP. Therefore, we considered the device to be dangerous, and decided to discontinue use. First we cultured samples from all of the automatic urine quantity measuring devices in our hospital. We found MDRP, S.maltophilia, and ESBL producing E.coli. We informed staff of the dangers of using the device. We then calculated how many patients were using automatic urine quantity measuring devices, how many patients with urine collection, and publicized the results in all departments. Furthermore, we asked physicians and nurses about the reasons for using the devices, and discussed the possibility of disuse. As a result, the number of patients who were using the device was reduced from 86 in November 2011 to 2 in June 2012. Finally, we removed all of these devices in July 2012. The number of patients with urine collection reduced from ten in November 2011 to four in June 2012. Urine collection was performed only on selected dates. The staff have developed a greater sense of infection control at the time of an outbreak. Therefore, any outbreak is a great chance to review and strengthen infection control activities. High personal commitment is necessary for ICT staff to act as leaders at the time of an outbreak.

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[in Japanese]

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