After the mass epidemic of the flu during the 2009/2010 season at a private junior and senior high school in Kanagawa Prefecture, a survey was conducted to investigate possible infection channels. The number of flu infections, initially limited to a few students belonging to extracurricular sports clubs during the 36th to 40th weeks of 2009, sharply increased following an all-school sports day event held in the 41st week, eventually affecting 14.4% of the entire student body. After the closing of 19 of 30 classes for 5 days of the same week in accordance to regional government standards, the number of affected individuals decreased at once, but subsequently increased following a cultural festival held in the 45th to 47th weeks, and infection rates reached 42.6% during the 2009/2010 season. However, there were no serious cases that resulted in any complications. Our investigations revealed that, of the two commuter bus routes, infection rates were significantly higher amongst students who used the busier, and more crowded, bus route compared to the less busy route. Across ages, junior high students contracted the flu at a significantly higher rate than high school students. In conclusion, our findings indicate that the standards defined by the regional government for the diagnosis and recognition of flu patients, and subsequent guidelines for school suspension were ineffective as far as infection prevention was concerned, possibly because asymptomatic and slightly symptomatic carriers were overlooked.
A care bundle is used during tracheal intubation for the prevention of ventilator-associated pneumonia (VAP). The care bundle involves many approaches to prevent infection, such as the correct positioning and adjusting of the endotracheal tube in order to prevent the passage of bacteria through the cuff and endotracheal tube, limiting the degree of sedation using the sedation scales in order to prevent oversedation, discontinuation of mechanical ventilation as soon as possible with aggressive weaning protocols, correct hand washing, use of sterile techniques for invasive procedures, and education and maintenance of clean environmental conditions for maintaining and improving conditions in the intensive care unit (ICU). Furthermore, the VAP prevention team, which includes nurses, pharmacists, doctors, and other experts, was launched to educate the staff working in the ICU on the use of this care bundle. Before starting our team activity in 2009, the VAP incidence per respirator use over 1,000 days was 15.19, but the incidence decreased to 7.09 (p<0.023) in 2010 and 7.13 (p<0.003) in 2011, respectively. The average days that the respirator was used was 7.55±9.48 days in 2009, 7.56±11.11 days (p>0.05) in 2010 and 4.99±7.69 days (p=0.009) in 2011, showing a significant decrease from 2009 to 2011. The introduction of the VAP preventive bundle was effective and successful in the ICU of our hospital; but further exercises and educational practices for VAP prevention must be continued in the future.
The clinical contact surfaces of dental practices are often contaminated by infectious agents, which leads to the potential for transmission of pathogens. We investigated effective and practical means for environmental disinfection based on bacteriological culture in a dental practice unit of an outpatient clinic in the Department of Dental and Oral Surgery of our hospital. After reinforcement of environmental disinfection with alcohol wiping, swab culture of the clinical contact surfaces still detected contamination with methicillin-resistant coagulase-negative staphylococci and endodontic bacteria, at levels as high as those found previously. When the alcohol was replaced by sodium hypochlorite in the wipes, a significant reduction was observed in the contamination level. To fully disinfect the difficult surfaces, a portable pulsed UV radiation device was additionally used, which resulted in marked reduction in the contamination. In conclusion, stepwise implementation of environmental disinfection based on swab cultures of the clinical contact surfaces of a dental practice unit proved useful for establishing an effective and practical method of disinfection, revealing the superior effectiveness of wiping with sodium hypochlorite with or without portable pulsed UV irradiation to wiping only with alcohol.
The frequency of linezolid-associated thrombocytopenia becomes higher if administration is continued for more than 14 days. However, as we had experienced this side effect among patients with renal dysfunction, we examined the relationship between renal dysfunction and linezolid-associated thrombocytopenia in 30 patients from October 2006 to July 2010. We found a negative correlation between creatinine clearance and rate of decline of platelet count. There was also a negative correlation between creatinine clearance and days required for recovery of platelet count after completing linezolid treatment. If patients with renal dysfunction should receive normal doses of linezolid, we should be careful because of the risk for higher rate of thrombocytopenia and/or delay of recovery in such patients.
Recently, adenosine triphosphate (ATP) has been developed as an index for cleanliness evaluation. In Japan, Kikkoman's Lumitester® PD–20 (PD–20) with the reagent LuciPac® Pen (LPP) and 3M's CleanTraceTM UNG3 (UNG3) with the reagents Clean TraceTM UXL (UXL) or Clean TraceTM AQT (AQT) are frequently used. However, correlation of the test results between these devices and reagents as well as permissible values are not clear. This study clarified the correlation and measurement limits with standardized ATP solutions and major bacterial suspensions measured using the following ATP devices and reagents: PD–20 with LPP (A-test), UNG3 with UXL (B-test), and UNG3 with AQT (C-test). Furthermore, cleanliness evaluation in medical field as an index of ATP and tolerance settings for repeat processing (cleaning, disinfection or sterilization) were assessed. Distilled water (control), standardized ATP solution, and four types of strain suspensions were measured 10 times with 10 μL of each reagent. All measured values were logarithmically converted. Distilled water had the following values: A-test 0.70 RLU, B-test 1.14 RLU, C-test 1.29 RLU. In all reagents, standardized ATP solution was within the range measurement limit of 10−16～10−17 mol/assay. The quantitative relationship for each reagent was positively correlated within the measurement range of the standardized ATP solution. The measured values of the standardized ATP and standardized strain suspensions increased in the order A-test, B-test and C-test. The measured values showed a high correlation with a coefficient of greater than 0.98 for any method and the slope of the regression line was close to unity. The measurement limits of Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa were estimated at 102～103 CFU/assay by all reagents, and for Candida albicans was 2.0 CFU/assay. The measured values were not absolute; comparison of the measured values is a problem in any method. Therefore, further evaluation with the same instruments and reagents should be continued. In addition, despite the considerably high sensitivity, specificity was thought to be low. Therefore, post washing that allows for some bacterial residue would be an ideal use for an index of ATP cleanliness in the medical field, as opposed to testing sterilized or disinfected medical devices. Tolerance values must be set for each method of cleaning by identifying the average ATP values.
Fluoroquinolone drugs are commonly used to treat respiratory tract and urinary tract infections. However, in recent years, resistance to fluoroquinolone drugs has been emerging among Escherichia coli strains. LVFX is a standard fluoroquinolone drug, so monitoring is necessary to identify resistance with increased use. The data from adult (≧18 years old) inpatients who were administered LVFX for infections caused by E. coli between July 2009 and March 2012 was analyzed. LVFX-resistant E. coli was associated with the history of hospitalization, underlying diseases such as malignant tumor and respiratory disorder, indwelling of urinary catheter, and the use of fluoroquinolone drugs within the previous 6 months. We should reconsider the use of LVFX in patients with such factors.
A nursery school is provided for the healthcare workers in our hospital. In April 2011, an outbreak of rotavirus infection occurred at the nursery school. At the time, the strategy of infection control for our nursery school was inadequate. An infection control team performed the following intervention: preparation of an infection control manual for the nursery school, and establishment of methods to report an outbreak and corresponding route of the infection. Our interventions led to increased awareness among the nursery school teachers and healthcare workers about infection control at the nursery school. Since then, no outbreak of infection has occurred in the nursery school. Therefore, sufficient intervention of an infection control team is necessary for nursery schools in hospitals.