Mycobacterium avium subspecies hominissuis (MAH), a nontuberculous mycobacterium, is sometimes detected in drinking water systems and bathrooms where it forms biofilm. MAH causes pulmonary disease, disseminated infections, and lymphadenitis in small children, transmitted from the environment to the human body via ingestion and inhalation of contaminated water and aerosols. Therefore, methods for disinfecting environmental biofilm-forming MAH are essential. Sodium hypochlorite is a chlorination agent widely used to disinfect water in drinking water systems and swimming pools, and chlorine dioxide also has potent bactericidal activity. However, the bactericidal activity of chlorine compounds against biofilm-forming MAH remains unclear. Therefore, we compared the disinfectant activities of sodium hypochlorite and chlorine dioxide against planktonic growing and biofilm-forming MAH cells. Concentrations of 100 and 1000 mg/L of sodium hypochlorite killed planktonic MAH cells (about 105 CFU/mL) within 30 and 5 min, respectively, whereas 10 mg/L of chlorine dioxide killed these cells within 5 min. MAH biofilm had cell counts of up to 108–109 CFU/well. Although 1000 mg/L of hypochlorite applied to MAH biofilm killed only 90% of these cells in 30 min, 100 mg/L of chlorine dioxide killed 99.99% of cells in 30 min. Therefore, chlorine dioxide is superior to sodium hypochlorite for the eradication of environmental MAH. However, MAH biofilm caused reduction in the bactericidal activity of chlorine-based disinfectants. Therefore, structural and functional analyses of MAH biofilm prepared using environmental isolates may facilitate eradication of environmental bacilli.
This study investigated subclinical aspiration as one of the risk factors responsible for nursing and healthcare-associated pneumonia (NHCAP) in severe multiple-handicap patients (severely handicapped children/people), and the causative bacteria of NHCAP (common NHCAP pathogens), which colonize both the saliva and sputum, as well as the influence of these bacteria on activities in daily life. This study included 13 severely handicapped patients (5 males and 8 females; median age, 19 years) hospitalized at our institution, all of whom required total assistance. Of the 13 patients, 7 obtained nutrition via nasogastric intubation and 6 had undergone gastrostomy. Additionally, 4 of the patients had a tracheotomy and 5 had undergone laryngotracheal separation. Saliva and aspirated sputum were collected at the same time, and the bacterial strains isolated from both samples were studied to identify the common NHCAP pathogens. Ninety-six strains and 82 strains were isolated from the saliva and sputum, respectively, and 49 strains were common to both saliva and sputum. Thirty-six strains of NHCAP pathogens were isolated and accounted for 38% and 44% of the total strains from the saliva and sputum, respectively. Additionally, the NHCAP pathogens accounted for 73% of the total strains that were common to both saliva and sputum. The common NHCAP pathogen strains isolated were identified as oral Streptococcus, H. influenzae, and P. aeruginosa, which were isolated from 8, 7, and 5 patients, respectively. The number of common bacteria (p<0.01) and streptoccocal species (p<0.05) were reduced by laryngotracheal separation. The findings of this study suggest that common NHCAP pathogens colonize severely handicapped patients, and aspiration is one of the risk factors for infection. Laryngotracheal separation reduces the risk of NHCAP due to oral streptoccoci. However, contamination and contact with the tracheal walls by healthcare providers may be an important factor in infection of the lower respiratory tract by common NHCAP pathogens from the oral cavity.
Three methicillin-resistant Staphylococcus aureus (MRSA) clinical isolates were identified in one ward of our hospital from February to March 2014. These 3 MRSA strains were isolated 48 hours or more after hospital admission. Antibiogram and PCR-based open-reading frames typing methods revealed that 4 MRSA strains which contained 1 strain isolated from a long-term inpatient originated from one clone. We carried out an environmental investigation of the ward to reveal the source and route of the nosocomial transmission of MRSA. Four MRSA strains isolated from the environment of this ward and were from the same clone, indicating that dissemination within the environment of this ward was responsible for the spread of MRSA. This nosocomial transmission was terminated by the intervention of the infection control team including environment improvement. This study shows that identification of the source and route of the spread is important to prevent nosocomial transmission.
Methicillin-resistant Staphylococcus aureus (MRSA) is an important pathogenic bacterium causing nosocomial infections. Using data from patients hospitalized between April 2012 and June 2013 in our hospital, we examined how the use of antibiotics and hand disinfectants affected the MRSA isolation rates. The antimicrobial use density (AUD), use of disinfectants, and MRSA isolation rates from all samples and blood culture samples were correlated for disinfectants (r=−0.34). Higher AUD of carbapenem (r=0.61), first-generation cephalosporin (r=0.59), and quinolone (r=0.48) were also correlated with increased MRSA isolation rates. Multidimensional analysis was performed to evaluate contribution to MRSA isolation rates. In the first analysis, the disinfectant had a contribution ratio of 20.7%. In the second analysis, the AUD of carbapenem had a contribution ratio of 12.7%. The cumulative contribution ratio of disinfectant plus AUD of carbapenem was 86.7%. This new analytic method allowed visualization and has contributed to reducing MRSA isolation rates.
International efforts continue to standardize metrics for monitoring multi-drug resistant organisms (MDRO), but no consensus for MDRO surveillance has been achieved in Japan. Therefore, we expect that MDRO surveillance will vary widely between hospitals. A survey examining which metrics are monitored at 8 hospitals was conducted, focusing on methicillin-resistant Staphylococcus aureus (MRSA) as a common MDRO in most Japanese hospitals. Five of the 8 hospitals used the MRSA infection or colonization incidence rate/incidence density rate to quantify healthcare acquisition, and one hospital used the MRSA bloodstream infection incidence rate to estimate infection burden. Some hospitals utilized the admission prevalence rate and the overall patient prevalence rate to assess the MRSA exposure burden. Data collection and definitions for calculating those metrics varied widely. Our findings demonstrate the disparities in surveillance practices for MRSA between hospitals. Hospital epidemiologists should participate in efforts to standardize MDRO surveillance, and research is urgently needed to identify the optimal metrics useful for the risk assessment of MDRO in Japan.
Hand-washing and hand hygiene are based on nosocomial infection control. However, many medical staff do not obey the hand hygiene guidelines, so improvement of the rate of hand hygiene compliance is very important. The rate of hand hygiene significantly increased from 3.2% in 2011 to 21.9% in 2013, following intervention by the infection control committee and ICT. Furthermore, the rates of detection of MRSA and newly detected MRSA decreased from 31.5% to 13.1% and 11.5% to 2.6%, respectively. These findings suggest that improvement of the rate of hand hygiene results in decreased detection of MRSA, and fewer new MRSA. This study shows that systematic assessment of nosocomial infection control is very important.
This study investigated the usefulness of training in hand hygiene using the full-hand touch plate method for psychiatric hospital staff. A total of 42 staff members working in a psychiatric hospital underwent hand hygiene training (3 hours in total for 2 days) using the full-hand touch plate method and group discussion. A self-completed questionnaire was given regarding hand hygiene before and after the training, and 16 (38.1%) participants provided completed questionnaires with effective answers. These participants included nurses (81.3%), kitchen staff (12.5%), and psychiatric social worker (6.3%). The perception of participants that hand hygiene is important was significantly higher after the training (p=0.02). Among the key moments for hand hygiene described in “My 5 Moments for Hand Hygiene” of the WHO, the perceived importance of hand hygiene “before touching a patient” and “after touching the surroundings of a patient” was significantly higher after the training (p=0.002). After the training, 87.5% of the participants felt that they had learned about the state of hand contamination before hand washing. In the hospital, the overall amounts of liquid soap and hand antiseptics used per 1,000 patient days were 6.3 and 0.3 L, respectively, in 2011. In contrast, the amounts had increased to 17.9 and 0.5 L, respectively, in the year of the training. Our findings suggest that hand hygiene training using the full-hand touch plate method for psychiatric hospital staff is effective to promote awareness of the importance of hand hygiene, and to encourage appropriate use of liquid soap and hand antiseptics.
As part of its reconstruction assistance following the Great East Japan Earthquake, the Japanese Nursing Association dispatched certified nurses in infection control (CNICs) to provide Hospital A, which sustained damages during the disaster, with education support for five months (19 sessions total). As a result, Hospital A developed infection control capabilities and made improvements in routine infection control. Furthermore, hospital staff promptly responded to and independently managed a norovirus outbreak that occurred immediately after the support concluded. Infection outbreaks in emergency shelters during the Great East Japan Earthquake were terminated by interventions from infection control specialists, but termination of an outbreak independently by an organization, as a result of education support, has never been reported before. Receptivity of the nursing staff and organizational culture were definitely important for the success seen in Hospital A. The main factors influencing behavior changes are thought to be “providing clear evidence for infection control measures,” “organizing and making improvements in duties” and “sharing of information among staff”.