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P4.19 Preventing Methicillin Resistant Staphylococcus aureus (MRSA) Bloodstream Infections (BSI) in Adult Intensive Care Units (ICU)
Poster Presentations Methods: Descriptive study for 2004–2005, in two ICUs: coronary surgical (10 beds) and medical-surgical (12 beds). Active surveillance infection control data collection, but the MRSA surveillance was passive. When MRSA culture is detected from patient who is or has been admitted in ICU, this patient is considered MRSA Index case. At that time it was done active research to detect carrier or infection in contact and index patients. Cluster MRSA possible was defined when some contact was positive to MRSA. If some contact was positive, it was tried to find the similarities and differences of the strains resistance to antibiotics and spread of phage types. Results: 1827 patients were admitted over period. It was detected 21 MRSA Index cases, which developed screening in 221 patients. 11 screening were negatives in all contacts, 9 had a contact nasal positive and another one had 2 positive contacts. Possible attack rate 4.9%. All carrier contacts developed nosocomial infection. The incidence rate of MRSA nosocomial infection was 1.7% in admitted patients. All strains (100%) of MRSA were susceptible to the fusidic acid, 69.2% to mupirocin, 22.2% to clindamycin, 23.5% to erythromycin and 100% resistant to ciprofloxacin. The phage typing proved differences between strains of contact and index cases. Conclusion: The passive surveillance can be enough to control MRSA but not eradication. The differences between strains prove that the cross transmission can be lower which was suspected. P4.19 Preventing Methicillin Resistant Staphylococcus aureus (MRSA) Bloodstream Infections (BSI) in Adult Intensive Care Units (ICU) D. Jenkins *, S. Agrawal. University Hospitals of Leicester NHS Trust (UHL), UK Background: Patients with MRSA BSIs have a high risk of death. Infection with MRSA in intensive care patients is particularly concerning. The Department of Health (DH) has set a target for English hospitals to reduce their incidence of MRSA BSIs by 60% from 2003/4 baseline rates by March 2008. Aim: To measure the impact of admission MRSA screening and daily triclosan washes and nasal mupirocin application, combined with isolation of MRSA colonised/infected patients, on the incidence of MRSA BSI in adult ICU patients. Methods: From January 2003 all patients admitted to the three combined adult medical and surgical ICUs (total of 34 beds) of UHL were screened for MRSA carriage/infection on admission, and commenced on daily washes with triclosan and nasal mupirocin application for the duration of their ICU stay. Any patient with positive MRSA admission screens, or MRSA isolated from subsequent clinical specimens, was placed in a single room. Otherwise patients were nursed in an open plan ward. Blood cultures were taken when clinically indicated. Repeat blood culture isolates within 14 days of a previous positive blood culture from the same patient were ignored (DH definition). Results: The average three-monthly incidence of MRSA BSI in the 4 years pre-intervention was 5.9. The incidence immediately fell on introduction of screening/decolonisation to a mean of 1.9 episodes per quarter (P = 0.0006). This represents a mean 16 episodes prevented each year. No increase in mupirocin resistance was noticed during this time. A reduction in the usage of vancomycin was also noted, with an associated cost saving. Discussion: This intervention was readily integrated into routine care of patients, with little extra work. Temporal analysis indicates an association with a sustained, marked reduction in MRSA BSI. The absence of concurrent controls prevents strong conclusions about the efficacy of this approach but these results suggest that a controlled trial would be merited.
S25 P4.20 Clinical Evaluation of Oxoid Chromogenic MRSA Agar J. Cooper1 *, R. Montgomery2 , A. Brown1 . 1 Oxoid Ltd, UK, 2 Queen’s Medical Centre, UK Methicillin-resistant Staphylococcus aureus (MRSA) are responsible for significant morbidity and mortality in hospitals, presenting challenges for infection control teams worldwide. In order to implement appropriate and effective infection control, accurate and rapid detection of MRSA colonisation and infection is essential. We report the results from a clinical evaluation of three commercially-available Chromogenic MRSA Screening Agars, alongside the existing method [OxacillinResistance Screening Agar (ORSA: Oxoid, UK)] at Queen’s Medical Centre, Nottingham. Media performance was evaluated for sensitivity and specificity over a 24 hour incubation period. High sensitivity and short incubation time is essential for the implementation of infection control strategies to limit cross infection. High specificity also allows effective use of resources by reducing unnecessary secondary testing. 467 samples were processed over a four day period yielding a total of 63 confirmed MRSA-positive samples. With the existing method, ORSA, only 78% of MRSA were detected with a specificity of 62%. CHROMAgar (Becton Dickinson, USA) gave a sensitivity comparable to ORSA (78%), but a higher specificity of 98%. MRSA ID (BioM´ erieux, France) did not yield any false positives, however its performance was compromised by the lowest level of sensitivity (67%) in this evaluation. Chromogenic MRSA Agar (Oxoid, UK) alone provided a high level of sensitivity and specificity with 97% and 98% respectively. Following this evaluation, Queen’s Medical Centre Infection control team recommended and subsequently implemented the replacement of ORSA with Oxoid Chromogenic MRSA agar as the standard MRSA screening medium at this facility. P4.21 High Contact Sites in Wards as Sources of MRSA Contamination? C.G. Gemmell1 *, M. Ferguson1 , A. Mead1 , C.M. Hamilton2 , P. Dandalides3 . 1 Dept of Bacteriology, Royal Infirmary, Glasgow, UK, 2 Dept of Infection Control, Royal Infirmary, Glasgow, UK, 3 Byotrol Healthcare Ltd, Manchester, UK Background: Nosocomial transmission of MRSA infection occurs largely through direct patient contact; inanimate surfaces within the ward environment contribute to its persistence. Ward cleanliness (or the lack of it) may contribute to MRSA transmission. Aim: The study seeks to show that a single cleaning intervention may reduce environmental contamination and thereby reduce MRSA nosocomial infection rates. Methods: Two ward areas with a history of high prevalence of MRSA infection were chosen. In one, comprising 8 bed-spaces, all high contact sites were wiped daily with a novel wipe containing several disinfectants bound to a siloxane polymer. In the other comprising 7 bed-spaces, normal cleaning practices were continued. Surface swabs were taken once/week of all treated sites and cultured on chromogenic agar (MRSA ID – bioMerieux). Patients were screened for MRSA on admission to ward and any showing signs of infection were cultured for MRSA. Patient movement in both ward areas was followed for 6 months. Over this period there were 234 in-patients. A switchover was effected after 4 months such that the additional disinfectant cleaning regimen was applied instead to the other ward area. Results: Levels of environmental MRSA were measured and MRSA ward maps were produced weekly. This allowed the detection of 4 new MRSA carriers. There was a reduced incidence of environmental MRSA in the disinfectant-treated areas. This occurred even in the presence of known MRSA infected patients within isolation rooms. Some sites such as
S25 P4.20 Clinical Evaluation of Oxoid Chromogenic MRSA Agar J. Cooper1 *, R. Montgomery2 , A. Brown1 . 1 Oxoid Ltd, UK, 2 Queen’s Medical Centre, UK Methicillin-resistant Staphylococcus aureus (MRSA) are responsible for significant morbidity and mortality in hospitals, presenting challenges for infection control teams worldwide. In order to implement appropriate and effective infection control, accurate and rapid detection of MRSA colonisation and infection is essential. We report the results from a clinical evaluation of three commercially-available Chromogenic MRSA Screening Agars, alongside the existing method [OxacillinResistance Screening Agar (ORSA: Oxoid, UK)] at Queen’s Medical Centre, Nottingham. Media performance was evaluated for sensitivity and specificity over a 24 hour incubation period. High sensitivity and short incubation time is essential for the implementation of infection control strategies to limit cross infection. High specificity also allows effective use of resources by reducing unnecessary secondary testing. 467 samples were processed over a four day period yielding a total of 63 confirmed MRSA-positive samples. With the existing method, ORSA, only 78% of MRSA were detected with a specificity of 62%. CHROMAgar (Becton Dickinson, USA) gave a sensitivity comparable to ORSA (78%), but a higher specificity of 98%. MRSA ID (BioM´ erieux, France) did not yield any false positives, however its performance was compromised by the lowest level of sensitivity (67%) in this evaluation. Chromogenic MRSA Agar (Oxoid, UK) alone provided a high level of sensitivity and specificity with 97% and 98% respectively. Following this evaluation, Queen’s Medical Centre Infection control team recommended and subsequently implemented the replacement of ORSA with Oxoid Chromogenic MRSA agar as the standard MRSA screening medium at this facility. P4.21 High Contact Sites in Wards as Sources of MRSA Contamination? C.G. Gemmell1 *, M. Ferguson1 , A. Mead1 , C.M. Hamilton2 , P. Dandalides3 . 1 Dept of Bacteriology, Royal Infirmary, Glasgow, UK, 2 Dept of Infection Control, Royal Infirmary, Glasgow, UK, 3 Byotrol Healthcare Ltd, Manchester, UK Background: Nosocomial transmission of MRSA infection occurs largely through direct patient contact; inanimate surfaces within the ward environment contribute to its persistence. Ward cleanliness (or the lack of it) may contribute to MRSA transmission. Aim: The study seeks to show that a single cleaning intervention may reduce environmental contamination and thereby reduce MRSA nosocomial infection rates. Methods: Two ward areas with a history of high prevalence of MRSA infection were chosen. In one, comprising 8 bed-spaces, all high contact sites were wiped daily with a novel wipe containing several disinfectants bound to a siloxane polymer. In the other comprising 7 bed-spaces, normal cleaning practices were continued. Surface swabs were taken once/week of all treated sites and cultured on chromogenic agar (MRSA ID – bioMerieux). Patients were screened for MRSA on admission to ward and any showing signs of infection were cultured for MRSA. Patient movement in both ward areas was followed for 6 months. Over this period there were 234 in-patients. A switchover was effected after 4 months such that the additional disinfectant cleaning regimen was applied instead to the other ward area. Results: Levels of environmental MRSA were measured and MRSA ward maps were produced weekly. This allowed the detection of 4 new MRSA carriers. There was a reduced incidence of environmental MRSA in the disinfectant-treated areas. This occurred even in the presence of known MRSA infected patients within isolation rooms. Some sites such as