Negative pressure room is indispensable for controlling airborne pathogens. However, no dynamic analysis of the distributions of droplet nuclei under various air conditions has been performed. Dynamics of droplet nuclei in the negative pressure room affected by air direction were examined using a Computational Fluid Dynamics (CFD) method. The concentrations of droplet nuclei in the room were increased immediately and reached a steady state 30 minutes after patient entry. The droplets in the breath were estimated to be diluted approximately 1,200 times after air release. Once the patient leaves the room, the concentration of droplet nuclei was decreased to one thousandth after 60 minutes. No reflux was observed into the ante-room unless the inner door was closed. After opening the door, the concentration in the anteroom increased dramatically due to the refluxed air. In addition, the impact of the positions of the inlet and outlets was assessed under the same air change rate. The distance between the orifice and the positions of the inlet and the outlets significantly affected the distributions of droplet nuclei. Dynamic analysis of the distribution of droplet nuclei using a CFD method may be useful in designing the optimal isolation room for patients with airborne pathogens.
Nebulizers are recognized as potential healthcare associated infection (nosocomial infection) agents. Microbial contamination was studied in inhaled solutions in ultrasonic nebulizers used in the clinical setting. Microbial contamination was detected in 19% of samples. Damage to medication cups by ultrasonics and backward saliva flow from a corrugated tube were considered possible causes of microbial contamination. No microbial contamination was detected in samples with new medication cups and the use of back-flow adapters.
Electric air hand dryers (AHD) are widely used in Japanese hospitals, but the AHD collects droplets from washed hands on a tray. These droplets are blown away with a strong air stream, which is potentially dangerous if the droplets contain harmful bacteria. This study investigated if droplets are contaminated with bacteria. Droplet trays of AHD from seven male and seven female toilets were swept with sterile swabs, then cultured in blood agar at 35°C for 48 hours. Thirteen of 14 AHDs had more than 1000 CFU/mL of bacteria. Interestingly, all AHDs from male toilets contained only normal flora of the skin such as Staphylococci and Microcococci, and no gastrointestinal flora. In contrast, AHDs in female toilets contained significantly fewer colonies of Staphylococci and Microcococci, but significantly more colonies of normal gastrointestinal tract flora such as Morganella. These results may reflect insufficient hand washing before using the AHD, as well as the differences in the body parts touched by the fingers after using the toilets. Droplets spread from AHDs are potentially hazardous because of significant bacterial contamination.
This study investigated infection control procedures for preventing pneumonia in long-term home-care patients who require endotracheal suctioning. We interviewed 20 patients and caregivers regarding the maintenance condition of endotracheal suction catheters and oral care of patients. At the same time, cleaning solution used before and after catheter suctioning, soaking solution used for catheter maintenance, and supragingival plaque sample were collected from each patient, and bacteriological examinations were performed. Of 20 patients, 20 had undergone tracheotomy, 18 were bedridden, and 15 had episodes of pneumonia. Of 20 caregivers who used catheters repeatedly for more than 24 hours, 16 were used soaking solutions and 4 used dry containers for catheter maintenance, and 8 used only one solution for cleaning and soaking. Serratia marcescens and Pseudomonas aeruginosa were isolated at high frequencies from the cleaning and/or soaking solutions of 14 and 6 patients, respectively. The solutions from 6 patients were highly contaminated by bacteria at levels exceeding 105 cfu/mL. Oral care was provided to most patients once or twice a day. However, P. aeruginosa, S. marcescens, and Klebsiella pneumoniae were isolated from the supragingival plaque samples of 16, 8, and 3 patients, respectively. Levels of these bacteria exceeding 105 cfu/mL were detected from supragingival plaque samples of 18 patients. P. aeruginosa and/or S. marcescens isolated from supragingival plaque samples of 17 patients were also isolated from the cleaning and/or soaking solutions of 11 patients. Infection control procedures are very important to practice for home-care patients at high risk for pneumonia, focusing on the use of clean catheters, and the necessity for improving the daily oral care strategy.
Irritant contact dermatitis is often found on the hands of health care workers. Alcohol-based hand rubs, which are used to prevent the transmission of nosocomial pathogens, may cause dry skin and burning sensation on previously irritated skin. Patients with eczema on the hands have higher rates of skin colonization by organisms such as Staphylocuccus aureus and multiple antibiotic-resistant strains. Therefore, a hygiene technique which does not cause skin damage to the hands is important to prevent the transmission of nosocomial pathogens. An MPC (2-methacryloyloxyethyl phosphorylcholine) polymer has been found to maintain higher hydration of the stratum corneum of the skin and to attenuate SLS-induced skin irritation on the skin. The present study investigated whether the usage of alcohol-based hand rubs with or without MPC polymer for 2 weeks might cause irritation of the skin using biophysical skin measurements. High frequency conductance measurements disclosed that a formulation without MPC polymer decreased skin hydration, whereas a formulation with MPC polymer tended to increase the skin hydration of healthy volunteers (n=36). Moreover, the formulation with MPC polymer was found to decrease transepidermal water loss, a parameter of the barrier function of the skin, and to cause less burning sensation compared to the formulation without MPC polymer. In conclusion, an alcohol-based disinfectant with MPC polymer may be useful for health care workers with skin damage of the hands due to frequent wet work, occlusion by gloves, and aggressive use of detergents and disinfectants.
Appropriate use of carbapenem broad spectrum antibiotics was promoted among clinical pharmacists in cooperation with a pharmacist specializing in infection control for 1 year and six months. Changes in the use of carbapenems were monitored. AUD of carbapenems was evaluated and change in susceptibility to carbapenem of detected Pseudomonas aeruginosa was compared in the periods before the activity started, during about 6 months after the start, and in the remaining study time. Use of carbapenem dose regimen twice a day decreased from 94.0% to 73.0% to 59.0%, and three times a day increased from 6.0% to 21.7% to 36.9%.The average dosage of carbapenems increased from 1.06 g to 1.20 g to 1.24 g per day. The AUD of carbapenems decreased from 14.6 to 13.5 to 11.2, and showed inverse correlation with the number of suggestions of clinical pharmacists. In addition, the susceptibility for IPM/CS of detected Pseudomonas aeruginosa improved from 53.2% to 68.1% to 73.1%, and the susceptibility for MEPM detected Pseudomonas aeruginosa improved from 66.5% to 70.9% to 78.6%. The use of carbapenems depends on empirical data, so we have to share the local antibiogram. We practice the dosage of antibiotics in consideration of kidney functions and MIC of assumed causative bacteria, as well as organization switchover of antibiotics, and consider de-escalation after the bacteria are clearly identified.
Changes in the compliance rate of hand hygiene were evaluated after ICU (Intensive Care Unit) nurses were given portable hand sanitizers and were educated about hand hygiene.The hand hygiene behaviors for a total of 16 ICU nurses at a tertiary emergency care center were evaluated by the constructive observation method. How nurses washed their hands and how many times they washed their hands were compared before and after the introduction of portable hand sanitizers, and the results showed that the nurses needed to wash their hands about 26 times an hour. The nurses rubbed their hands more often, and in fact, the compliance rate of hand hygiene improved about 27%. However, after the introduction of portable hand sanitizers, the number of nurses who did not wash their hands with soap and water increased by 25%. Also, the compliance rate decreased after the introduction of portable hand sanitizers in 12.5% of the nurses, and these nurses washed their hands with soap and water less. The compliance rate of hand hygiene tended to be low for nurses with less nursing experience. After the introduction of portable hand sanitizers, the compliance rate of hand hygiene for different types of nursing care improved, but the compliance rate of hand hygiene after touching ME (Medical Equipment) and instruments around patients was low. Therefore, hand hygiene education must consider the background factors and care responsibilities of ICU nurses. Hand hygiene after touching ME and instruments around patients is thought to be an important step for preventing contact infection in the ICU.