Interferon Gamma Release Assay (IGRA) is an indispensable method for diagnosing tuberculosis infection because of its excellent specificity and sensitivity owing to M. tuberculosis specific antigens. There seems to be no significant difference in sensitivity or specificity between QuantiFERON Gold In-tube and T–SPOT TB, both of which are available in Japan. Results of IGRA wane after a certain time from infection or fluctuate if it is repeated. Therefore, careful consideration is required for interpretation. For infection control in medical facilities, IGRA at the start of employment is recommended to get baseline datum, however, LTBI treatment for a positive reactor is unnecessary, if recent infection is not probable. For contact examination, the examinee should be decided depending on infectiousness and infectious period of the index case, closeness of contact, and individual risk for developing active disease. Timing of IGRA is basically two to three months after the final contact. However, modification should be considered depending on the situation. It is significant for hospital infection control to give LTBI treatment for immune-depressed patients with high risk for developing tuberculosis. Careful consideration for influence of the immune-depressed condition is required to interpret the data.
Antibiotic therapy for the prevention of postoperative infections is intended to achieve prophylaxis for surgical site infections (SSIs) and is not indicated for prevention of other postoperative infectious complications, including remote infections. The antibiotics used target bacteria that are normally present at a surgical site, whereas broad-spectrum antibiotics are not generally employed. Various antibiotics are recommended for the prevention of postoperative infections, including cefazolin (CEZ) or sulbactam/ampicillin (SBT/ABPC) for clean surgical wounds, and cefotiam (CTM), a second-generation cephamycin (cefmetazole: CMZ), an oxacephem (flomoxef: FMOX), or a combination of CEZ and metronidazole (MNZ) for clean-contaminated wounds. Administration of these antibiotics should be started within one hour prior to surgery. The dosage and the number of doses of these antibiotics should be adjusted depending on the patient's body weight and renal function. In principle, administration of these antibiotics should cease within 24 hours after surgery.
The purpose was to evaluate the effect of antimicrobial use density (AUD) on Clostridium difficile infection (CDI). Monthly ward data included AUDs of parenteral antimicrobials for three years. For a total of 129 CDI patients, multivariate analysis showed that pediatric and obstetrics wards (odds ratio [95% confidence interval], 0.119 [0.024-0.585]; p=0.009) and AUDs of cefazolin (0.377 [0.207-0.687]; p=0.001), flomoxef (0.531 [0.294-0.961]; p=0.036), and ceftazidime (2.038 [1.072-3.874]; p=0.030) were significant. AUDs carrying risk of CDI await further analysis.
Cleaning of environmental surfaces, as well as hand hygiene, is very important to prevent infection caused by microbes found in the environment of medical facilities, and disinfection is also required for environmental infection control in some cases. Recently, wet wipes made of nonwoven fabric impregnated with cleaner or disinfectant (medicinal solution) have been widely used for maintenance of the hospital environment. Evaluation of the sanitizing efficacy of wet wipes has mainly been based on allowing only the medicinal solution to contact with the test microbe, although the effectiveness of the product might be affected by adsorption of the medicinal solution into the fabric. This study evaluated the antibacterial and virus inactivation efficacy of three commercial products (brand A, brand B, and brand C) and wet wipes impregnated with Ethanol for Disinfection (ethanol wipes) using (1) a quantitative suspension test in which the solution squeezed from each test product was allowed to contact with the test microbe, and (2) a fabric wipe-processing test in which the contaminated surface was wiped off with each test product. Brand A demonstrated superior effect against the test microbes in both the quantitative suspension test and fabric wipe-processing test in comparison with brand B and brand C. Brand A was also superior to ethanol wipes for virus inactivation in the fabric wipe-processing test. Brand B, brand C, and ethanol wipes showed apparent differences between the results of the quantitative suspension test and fabric wipe-processing test. These results suggest that the combination of both tests is useful for rigorous evaluation of the effectiveness of wet wipes.
To assess the characteristics of positive blood cultures in a tertiary medical center in Japan, 332 positive blood culture episodes were reviewed from 241 patients at a university hospital in 2012. These episodes were considered to represent true bacteremia or contamination at the discretion of the judging panel in the hospital's department of infection control and prevention. The correlations were examined between episodes of true bacteremia or contamination, identities of isolated bacteria, time to positivity (TTP) of blood culture, underlying medical conditions, catheter placement, and antibiotic therapies. A total of 244 of 332 positive blood culture episodes (75.8%) represented true bacteremia. Microorganisms frequently found in true bacteremia were fungus (11/11, 100.0%), gram-negative rods (95/99, 96.0%), and Staphylococcus aureus (43/45, 95.6%), whereas coagulase-negative staphylococci (38/93, 40.9%) was less common. The mean TTP of blood cultures representing true bacteremia and contamination was 22.1 hours and 31.6 hours, respectively. The difference in TTP for each group was more than 10 hours for staphylococci and enterococci, although this trend was not observed for other microorganisms. Antibiotic therapy was administered in 156 of the 175 cases of true bacteremia. Among these cases, antibiotic therapy was initiated before performing blood culture in 43 cases, simultaneously with blood culture in 45 cases, after positive blood culture was reported in 50 cases, and when the identity or antibiotic susceptibility of the isolated microorganism was reported in 18 cases. These findings will facilitate the confirmation of true bacteremia in clinical settings, and, in combination with improvements in the laboratory reporting system, will improve future therapies for patients with bacteremia.
An outbreak of norovirus infections, affecting 16 patients and five nurses, occurred on two wards in our hospital. The infections developed coincidently in multiple rooms on the wards. An epidemiological study suggested that the norovirus had been first introduced into the south ward and then spread to the main ward via a contaminated communal toilet equipped for patients in wheelchairs. Accordingly, we implemented a program of thorough cleaning and disinfection using sodium hypochlorite throughout the ward environment, including the communal toilets, and promoting hand hygiene after using the toilet among inpatients. Following this intervention, the outbreak swiftly ceased. We recommend that wearing personal protective equipment and isolating infected patients in private rooms, as well as cleaning and disinfecting the environment, including communal toilets, are essential actions during norovirus outbreaks.
This study investigated the actual conditions of hand hygiene after diaper exchange conducted by staff working in special elderly nursing homes, and discusses hand hygiene education. A survey based on observation research and self-administered questionnaires was conducted targeting 115 staff working in four special elderly nursing homes. According to observation research, only 3.5% of the subjects performed correct hand hygiene. In contrast, the Health, Labour and Welfare Ministry study “Research on How Infection-control in Elderly Nursing Institutes should be” found the hand-washing implementation rate after diaper-changing was 64.3%, and alcohol-based hand-finger disinfection rate was 73.4%. However, the glove-wearing rate was 100%, which was considered to be a substitution for hand hygiene. According to the self-administered questionnaire, 90.1% of the subjects performed hand hygiene. These findings emphasize the difference between subject awareness and actual behavior, and had similar results for appropriate timing of exchanging gloves. Therefore, any survey concerning hand hygiene should be based on observation. Hand-finger education in special elderly homes must emphasize the necessity of hand washing with the knowledge of the characteristic, of gloves, and practical work methods to achieve hand hygiene, and appropriate timing for exchanging gloves.