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P11.10 A global approach for microbial environmental contamination study in dental clinic
Abstracts, 7th International Conference of the Hospital Infection Society, 10–13 October 2010, Liverpool, UK / Journal of Hospital Infection 76S1 (2010) S1–S90
P11.08 The effect of a mobile air purification unit on the air quality of a room contaminated with Aspergillus sp. P. De Waegemaeker1 , N. Bovyn1 , M. Vanneste1 , G. Verschraegen2 . 1 University Hospital Ghent, Belgium; 2 University Ghent, Belgium Background: In early spring 2009, after a period of heavy rainfall, a strong fungal smell in old prefab building, used as a bedhold for patients, became obvious. The Hospital Infection Control Team (HICT) was summoned to evaluate the situation. Initial air samples showed a high load of Aspergillus sp. The prefab construction was closed immediately, creating an instant laboratory for the HICT to evaluate a mobile air purification unit (Genano 310). Objective: The first aim of the study was to determine whether the Genano was able to purify the air of Aspergillus spores. Furthermore, we wanted to determine if a link could be found between microbiological air sampling and particle counting. Method and Results: The bedhold was divided into two equal parts, separated by a plastic wall. One side became a testing area for the Genano. The other side was used as control area. Both microbiological air sampling and particle counting where used. In the control area, a single measuring point was selected at the centre of the room. In the testing area 8 measuring points where selected for particle counting, one for air sampling. Conclusions: 1. The Genano 310 was able to improve the air quality with a ratio 2.3 up to 3.3 (depending on particle size). 2. Although scientifically weak, there was an obvious relationship between the particle counts and the microbiological samples. Discussion: We found a significant improvement of the air quality in a microbiological heavily contaminated room using a mobile air purification unit. After shutting down the equipment, the air quality returned to its initial state. The question remains if and how this would reflect in patient infection rates. A more longitudinal design study should give more answers. Based upon the experience with particle counting, we decided to start using it as a standard surveillance method in our daily practice. It turned out to be a great asset. P11.09 Water microfiltration at the point of use – a procedure to prevent infection/colonization with water borne pathogens in ICU patients? M. Hell1 , C. Unterkoefler1 , M. Dollenz1 , B. Richling1 , C. Luger2 , H. Mittermayer2 , M. Maass1 . 1 University Hospital Salzburg, Austria; 2 Krankenhaus der Elisabethinen/Austrian Reference Centre for Nosocomial Infections and Resistence Surveillance, Austria Objectives/Background: There is an ongoing debate whether Pseudomonas aeruginosa is of endogenous or exogenous origin in the respiratory tract of intensive care unit patients while performing active surveillance cultures. We observed a cluster of five P. aeruginosa colonization/infection in the tracheal secretions in long-term-ventilated patients of a neurosurgical intensive care unit in September 2007. Methods: We performed a controlled study with an historical control group before installing bacterial water filters at the point of use. This tap water is regularly used for nursing intensive care unit patients. A three-year retrospective study prior to intervention was done. The control period after the intervention was twelve months. P. aeruginosa positive patients before and after filter-installation were compared. Additionally we investigated the available isolates from patients and from tap water samples for molecular typing to demonstrate the clonal and/or exogenous origin. Results: We were able to demonstrate epidemiologically a reduction in the P. aeruginosa colonization/infection rate in the post-intervention period (0.95 cases/1.000 ventilation days postintervention versus 7.13 cases/1.000 ventilation days prior to
S35
intervention) which was statiscally significant. By means of pulse field gel electrophoresis the clonal identity was confirmed molecularly since two of the five examined patients clearly had the same genotype as the examined water isolates. Conclusions: On basis of this data we were able to show that during patient care the source of the clonal origin of P. aeruginosa was indeed the water tap and to demonstrate epidemiologically the efficacy of water microfiltration in high risk areas. This decrease suggests a high efficacy of point of use water microfilters and a recommendation for the installation of such microfilters for intensive care units could be made. P11.10 A global approach for microbial environmental contamination study in dental clinic C. Pasquarella, E. Capobianco, S. Pizzi, P. Vitali, F. Paganuzzi, L. Veronesi, M.L. Tanzi. University of Parma, Italy Background: The dental practice is associated with a high risk of infections, both for patients and healthcare operators, and the environment may play an important role in the transmission of infectious diseases. Aim: To study the microbial contamination of the dental clinic considering all environmental matrices (water, air and surface) as a basic knowledge for targeted preventive intervention. Methods: The study was carried out at the dental clinic of Parma University Hospital. Microbial contamination of water, air and surfaces was assessed during the five working days of the week, before, during and after treatments. Tap water and dental unit water system (DUWS) were sampled to assess the total viable count (TVC) at 36°C and 22°C, and the presence of Legionella spp. and P. aeruginosa. Microbial air contamination was evaluated by active sampling and by passive sampling; surfaces were evaluated by RODAC plates at the countertop serving the monitored dental unit and on the dental unit switch. Results: Microbial water contamination decreased significantly during clinical activity both at tap water and at DUWS (p < 0.05) for TVC; 55% of samples from tap water exceeded the threshold values established by the European Directive 98/83/EC; 82% of all dental unit samples exceeded the CDC (2003) threshold value of 500 cfu/mL. Legionella spp. and P. aeruginosa were found in 10% and 50% of samples respectively. Microbial air contamination showed a significant increase between before and during dental treatments (p < 0.05), followed by a significant decrease after the end of the working activity (p < 0.05). As for surface while an increase was observed during the working activity, no significant decrease was found after the end of the daily activity. Conclusion: Our study is an example of hazard analysis in dental clinic which has highlighted some critical points on which intervene, in order to control the infectious risk associated to dental practice. P11.11 The effectiveness of a hospital environment maintenance aimed at the infection prevention against Pseudomonas aeruginosa in Japan K. Imaizumi1 , Y. Sato1 , M. Igari1 , K. Ishii1 , M. Endo1 , K. Kan1 , Y. Teranishi1 , S. Hatae2 , M. Takagi1 , H. Miyamoto1 . 1 Southern Tohoku General Hospital, Japan; 2 ICHG, Japan Background: Due to the humid climate in Japan, the hospital infection caused not only by the bacteria which normally live in the moist environments including Pseudomonas aeruginosa (PA), Acinetobacter and Serratia, but also by a drug-resistant organism is problematic. In our general hospital with 450 beds, a high incidence of infection due to PA and multi-drug resistant Pseudomonas aeruginosa (MDRP) had been an issue. Although the education of
P11.08 The effect of a mobile air purification unit on the air quality of a room contaminated with Aspergillus sp. P. De Waegemaeker1 , N. Bovyn1 , M. Vanneste1 , G. Verschraegen2 . 1 University Hospital Ghent, Belgium; 2 University Ghent, Belgium Background: In early spring 2009, after a period of heavy rainfall, a strong fungal smell in old prefab building, used as a bedhold for patients, became obvious. The Hospital Infection Control Team (HICT) was summoned to evaluate the situation. Initial air samples showed a high load of Aspergillus sp. The prefab construction was closed immediately, creating an instant laboratory for the HICT to evaluate a mobile air purification unit (Genano 310). Objective: The first aim of the study was to determine whether the Genano was able to purify the air of Aspergillus spores. Furthermore, we wanted to determine if a link could be found between microbiological air sampling and particle counting. Method and Results: The bedhold was divided into two equal parts, separated by a plastic wall. One side became a testing area for the Genano. The other side was used as control area. Both microbiological air sampling and particle counting where used. In the control area, a single measuring point was selected at the centre of the room. In the testing area 8 measuring points where selected for particle counting, one for air sampling. Conclusions: 1. The Genano 310 was able to improve the air quality with a ratio 2.3 up to 3.3 (depending on particle size). 2. Although scientifically weak, there was an obvious relationship between the particle counts and the microbiological samples. Discussion: We found a significant improvement of the air quality in a microbiological heavily contaminated room using a mobile air purification unit. After shutting down the equipment, the air quality returned to its initial state. The question remains if and how this would reflect in patient infection rates. A more longitudinal design study should give more answers. Based upon the experience with particle counting, we decided to start using it as a standard surveillance method in our daily practice. It turned out to be a great asset. P11.09 Water microfiltration at the point of use – a procedure to prevent infection/colonization with water borne pathogens in ICU patients? M. Hell1 , C. Unterkoefler1 , M. Dollenz1 , B. Richling1 , C. Luger2 , H. Mittermayer2 , M. Maass1 . 1 University Hospital Salzburg, Austria; 2 Krankenhaus der Elisabethinen/Austrian Reference Centre for Nosocomial Infections and Resistence Surveillance, Austria Objectives/Background: There is an ongoing debate whether Pseudomonas aeruginosa is of endogenous or exogenous origin in the respiratory tract of intensive care unit patients while performing active surveillance cultures. We observed a cluster of five P. aeruginosa colonization/infection in the tracheal secretions in long-term-ventilated patients of a neurosurgical intensive care unit in September 2007. Methods: We performed a controlled study with an historical control group before installing bacterial water filters at the point of use. This tap water is regularly used for nursing intensive care unit patients. A three-year retrospective study prior to intervention was done. The control period after the intervention was twelve months. P. aeruginosa positive patients before and after filter-installation were compared. Additionally we investigated the available isolates from patients and from tap water samples for molecular typing to demonstrate the clonal and/or exogenous origin. Results: We were able to demonstrate epidemiologically a reduction in the P. aeruginosa colonization/infection rate in the post-intervention period (0.95 cases/1.000 ventilation days postintervention versus 7.13 cases/1.000 ventilation days prior to
S35
intervention) which was statiscally significant. By means of pulse field gel electrophoresis the clonal identity was confirmed molecularly since two of the five examined patients clearly had the same genotype as the examined water isolates. Conclusions: On basis of this data we were able to show that during patient care the source of the clonal origin of P. aeruginosa was indeed the water tap and to demonstrate epidemiologically the efficacy of water microfiltration in high risk areas. This decrease suggests a high efficacy of point of use water microfilters and a recommendation for the installation of such microfilters for intensive care units could be made. P11.10 A global approach for microbial environmental contamination study in dental clinic C. Pasquarella, E. Capobianco, S. Pizzi, P. Vitali, F. Paganuzzi, L. Veronesi, M.L. Tanzi. University of Parma, Italy Background: The dental practice is associated with a high risk of infections, both for patients and healthcare operators, and the environment may play an important role in the transmission of infectious diseases. Aim: To study the microbial contamination of the dental clinic considering all environmental matrices (water, air and surface) as a basic knowledge for targeted preventive intervention. Methods: The study was carried out at the dental clinic of Parma University Hospital. Microbial contamination of water, air and surfaces was assessed during the five working days of the week, before, during and after treatments. Tap water and dental unit water system (DUWS) were sampled to assess the total viable count (TVC) at 36°C and 22°C, and the presence of Legionella spp. and P. aeruginosa. Microbial air contamination was evaluated by active sampling and by passive sampling; surfaces were evaluated by RODAC plates at the countertop serving the monitored dental unit and on the dental unit switch. Results: Microbial water contamination decreased significantly during clinical activity both at tap water and at DUWS (p < 0.05) for TVC; 55% of samples from tap water exceeded the threshold values established by the European Directive 98/83/EC; 82% of all dental unit samples exceeded the CDC (2003) threshold value of 500 cfu/mL. Legionella spp. and P. aeruginosa were found in 10% and 50% of samples respectively. Microbial air contamination showed a significant increase between before and during dental treatments (p < 0.05), followed by a significant decrease after the end of the working activity (p < 0.05). As for surface while an increase was observed during the working activity, no significant decrease was found after the end of the daily activity. Conclusion: Our study is an example of hazard analysis in dental clinic which has highlighted some critical points on which intervene, in order to control the infectious risk associated to dental practice. P11.11 The effectiveness of a hospital environment maintenance aimed at the infection prevention against Pseudomonas aeruginosa in Japan K. Imaizumi1 , Y. Sato1 , M. Igari1 , K. Ishii1 , M. Endo1 , K. Kan1 , Y. Teranishi1 , S. Hatae2 , M. Takagi1 , H. Miyamoto1 . 1 Southern Tohoku General Hospital, Japan; 2 ICHG, Japan Background: Due to the humid climate in Japan, the hospital infection caused not only by the bacteria which normally live in the moist environments including Pseudomonas aeruginosa (PA), Acinetobacter and Serratia, but also by a drug-resistant organism is problematic. In our general hospital with 450 beds, a high incidence of infection due to PA and multi-drug resistant Pseudomonas aeruginosa (MDRP) had been an issue. Although the education of