Contamination by methicillin-resistant Staphylococcus aureus (MRSA) of the patient care environment in the ICU was investigated at two institutions. The care environments of 33 patients who had undergone mechanical ventilation were surveyed from June until August 2006, from April until September 2007, and from June until October 2009. A total of 395 specimens were obtained from locations such as bed sheets and rails, buttons on mechanical ventilators, stethoscopes, and Jackson Rees. MRSA contamination was detected in 20.0% (28/140) of the specimens from the care environments of 11 inpatients with MRSA–positive body sites. MRSA was detected on bed sheets in 35.3% (6/17) of the specimens and on button sites in 29.4% (5/17) of the specimens in the 48–h period after admission to the ICUs. Contamination of the environment of MRSA–positive patients was detected soon after admission (<24 hours, 7/55), and the percentage of contamination increased with time (≥48 hours, 21/85). On the other hand, MRSA was not detected in the environment at 24 hours after admission of MRSA–negative patients to the ICU, and was detected at only two locations even at ≥48 hours after admission. In addition, in the hospital rooms of MRSA–negative patients, genetic analysis using pulsed-field gel electrophoresis detected only MRSA from the care environment of MRSA–positive patients who were admitted to the ICU earlier. MRSA can survive in the environment for an extended period of time. The present findings suggest that MRSA can be transmitted through contact with a contaminated patient care environment in hospitals.

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  An outbreak of Pseudomonas aeruginosa producing metallo–β-lactamase (MBLPA) in the hematology ward was controlled after use of toilet seats with bidet functions was terminated. Twenty four strains of MBLPA were identified from hospitalized patients in the hematology unit from January 2007 to December 2012. Multidisciplinary interventions including routine active surveillance, strengthening contact precautions, and analysis of risk factors for MBLPA were performed. However, new MBLPA infections continued to be identified after institution of infection control strategies. During the outbreaks, environmental surveys were conducted and 6 MBLPA isolates were detected from the spray nozzles of the toilet seats with bidet functions in this ward. Twenty four MBLPA isolates from the patients and 6 from spray nozzles were analyzed for chromosomal DNA typing by PCR–based ORF typing (POT). All 24 MBLPAs from the patients and all 6 isolates from nozzles had the same POTS patterns (Pot No. 644–41). Use of the toilet seats with bidet functions was discontinued during January to September 2013 and only 1 new isolate was identified in this period. Use of the toilet seats with bidet functions in October 2013 and 2 new MBLPAs were identified in only 3 months. Therefore, use of toilet seats with bidet functions was again terminated since January 2014 and occurrence of new isolates decreased again (1 isolate during 12 months). Incidence of MBLPA isolate per 1000 patient-days was 0.49 in the period of use of the toilet seats with bidet functions and 0.10 in the period of no use. In conclusion, use of toilet seats with bidet functions in the hematological unit is highly suspected as a risk factor for transmission of MBL producing Pseudomonas aeruginosa.

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  The corrosiveness of 2% RST (chlorine-releasing disinfectant cleaner consisting mainly of potassium peroxymonosulfate) on the surface materials used in hospital facilities compared with 1% sodium hypochlorite and 75% ethanol. Static immersion tests were performed on specimens of six resins (polypropyrene, polycarbonate, polystylene, acrylic resin, latex rubber, silicon rubber) and three metals (copper, stainless steel, aluminum). Copper was discolored and lost its luster one day after immersion in 2% RST solution, and aluminum was discolored and lost its luster 2 days after immersion. No changes were observed in stainless steel and resin materials 7 days after immersion in 0.1% NaOCl solution, whereas stainless steel, copper and aluminum were significantly corroded one day after immersion. Acrylic resin was clouded one day after immersion in EtOH and had gained weight 7 days later. Our findings show that 2% RST solution is less corrosive to stainless steel than 0.1% NaOCl, and less damaging to acrylic resin than EtOH. Therefore, RST is considered to be the least damaging disinfectant cleaner for the daily hygiene management of environmental surfaces.

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  Surveillance culture surveys targeting methicillin-resistant Staphylococcus aureus (MRSA) are often conducted at high-risk wards such as intensive care units. The surveillance culture strategies vary depending on the conditions at each institute, but cost-effectiveness should be considered on the individual institute basis to avoid excessive labor and financial costs. In our hospital, the numbers of culture specimens increased 1.5 times every year from 2005 to 2010. Among the various types of culture specimens, the numbers of feces and nasal swabbing samples increased more sharply, suggesting increased frequencies of surveillance cultures. This trend was most prominently observed in the neonatal intensive care unit (NICU), so how surveillance culture was performed in the NICU was further investigated. In 2008, when MRSA isolations increased in the NICU, weekly examination of both feces and nasal swabbing specimens started routinely for all hospitalized infants. However, this surveillance method seemed not to be optimally cost-effective, because retrospective analysis of MRSA isolations revealed that MRSA was usually identified in both samples at the same time and colonized afterward in most infants carrying MRSA. Therefore, we changed the surveillance culture strategy in 2011 to limit surveillance culture specimens to nasal swabbing, and once MRSA had colonized, surveillance culture was discontinued. These changes resulted in 32% reduction of sample numbers with estimated 74% cost savings for surveillance culture per year. In conclusion, epidemiological analyses can help to improve the cost-effectiveness of surveillance culture surveys.

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  Hospital staff members who had contact with 32 patients infected with tuberculosis over 7-year period were examined, including by interferon–γ release assay. Sixteen staff members tested negative in the initial test but were then found to be positive 10 weeks later, and were diagnosed with latent tuberculosis infection. All infected hospital staff made claims for workers' compensation which were accepted. The number of staff with latent tuberculosis infection was very high in 2011 and 2012 (8 and 6, respectively), then decreased to 1 each in 2013 and 2014, so infection was not totally eliminated. Prevention of TB infection of hospital personnel on duty requires that physicians must consider TB in diagnosis and reduce physician-associated delays.

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  An outbreak of seasonal influenza A occurred in the orthopedics ward of our acute care hospital in Nagasaki, Japan, at the end of January 2013. The present study evaluated the measures implemented to control the spread of the virus and propose strategies for managing possible future outbreaks. Influenza symptoms were observed in a female inpatient in her fifties who was admitted in the orthopedic ward of the hospital on January 25, 2013. Two days later, three additional inpatients who were admitted in different rooms developed influenza A. One inpatient and one nurse who worked in the ward developed the same disease on January 28. Based on these cases, we declared an outbreak of influenza A and intensified measures against nosocomial infections. The number of influenza A cases had reached 13 by January 31, so oseltamivir phosphate was administered as prophylaxis to the ward staff and patients (n=78). The outbreak ceased on day 18 after the index case was detected. Data from a retrospective cohort study of 46 inpatients in the orthopedics ward showed that nine of the 11 patients with disease onset used the same rehabilitation room and that the relative risk of developing influenza A in patients treated by one particular physiotherapist was 3.43 (95% confidence interval: 1.05–8.44; p=0.025). However, we were unable to determine the source of infection and the means of transmission of the infection. The orthopedic inpatients were well capable of activities of daily living, which was thought to contribute to the spread of the infection because of the wide area where these activities were performed. In addition, the opportunities for close contact were high in the rehabilitation room. Our experience shows that the first case should be carefully managed and thorough instruction on hand hygiene and cough etiquette, as well as enforcement of the droplet precautions and contact precautions, are necessary in the orthopedics ward early in the influenza season. In the future, these measures should be performed quickly before prophylaxis treatment in order to control the spread of infection.

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  Information useful for the prevention of blood-borne infections was collected by conducting a questionnaire study to assess the current status of needlestick injuries and hepatitis B vaccination at general dental practices. Ninety-seven dental care workers (74 dentists, 13 dental hygienists, and 10 dental assistants) working for dental clinics in Sumida City, Tokyo, Japan were enrolled. According to the questionnaire replies, 70.3% of the dentists and 77.2% of the dental hygienists and dental assistants had been exposed to needlestick injuries. Most needlestick injuries suffered by the dentists occurred during the administration of anesthesia by syringe. Needlestick injuries suffered by the dental hygienists and dental assistants were caused by more varied procedures and instruments. In total, 59.4% of the dental care workers enrolled in the study had been immunized with the hepatitis B vaccine. The vaccination rate was low among dental hygienists, dental assistants, and dentists aged over 50 years old. Only 9% of the dental care workers took appropriate responses (washing the needlestick wounds and visiting hospitals) after exposure to needlestick injuries. The rate of hepatitis B vaccination and post-injury responses were insufficient in the general dental practices studied. Most dental care workers in general dental practices are vulnerable to needlestick injuries, but their rate of hepatitis B vaccination and post-injury responses are inadequate.

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  Preparation of infusions on clinical wards requires preventive measures against contamination. To clarify the current status of infusion preparation, a multicenter study was conducted, involving hematology and surgery wards and focusing on air cleanliness, environments for preparation, and the content of each infusion. The air cleanliness level was measured in 9 departments of 5 facilities, using a particle counter and air sampler to identify airborne particles and microbes and clarify the number of colonies per 1 m³. Environments for the preparation of infusions and infusion contents were examined in 13 departments of 9 facilities by confirming the sites of preparation and totaling the numbers of injection prescription sheets issued during a 10–day period (a total of 7,201 prescriptions). Measurement of air cleanliness found the number of particles with a diameter of 5 μm or larger in a department ranged from 3,091×10³ to 393×10³/m³. Airborne microbes analysis found Staphylococcus aureus in only 3 departments, but detected human- or environment-derived CNS (coagulase negative staphylococci) and Micrococcus, Corynebacterium, and Bacillus species in all departments. Preparation tables were placed directly underneath air conditioner outlets in 9 departments (69%), and interfered with staff traffic lines in 10 departments (77%). Approximately 31% of the 4,089 prescription drugs, which had been subject to accidental mixture, were used for 3–hour or longer infusion. Manuals for the preparation of infusions on wards were available in only 3 of the 9 facilities. Considering the low air cleanliness level in areas with preparation tables, and the finding that more than 30% of prescription drugs were used for 3–hour or longer infusion, the risk of bacterial contamination is likely to be high. Guidelines for the appropriate preparation of infusions on clinical wards should be established to reduce such risks.

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