Die Innenausbauflächen von Krankentransport- bzw. Rettungswagen unterliegen dem Risiko einer Verunreinigung durch Methicillin-resistenten S. aureus (MRSA). In der vorliegenden Arbeit wurden Krankentransport- bzw. Rettungswagen unmittelbar nach dem Transport von MRSA-kolonisierten oder -infizierten Patienten auf MRSA untersucht. Zu diesem Zweck wurden an 2 Stellen der Trage und an 3 Stellen der Innenausbauflächen Proben entnommen. 89 von 100 untersuchten Transporten, welche das Einschlusskriterium einer Transportzeit von weniger als 20 Minuten erfüllten, wurden weitergehend analysiert. 8 der untersuchten Kranken- bzw. Rettungswagen (7,1%) wiesen eine Kontamination auf (90% Konfidenzintervall: 4-14 %), wobei die Transportzeit keinen Einfluss auf die Kontamination hatte. MRSA wurde nur an der Trage nachgewiesen und zwar ausschließlich am Kopfteil der Trage und an den Tragegriffen. Die beprobten Stellen der Innenausbauflächen waren nicht kontaminiert. Bei Kurzzeittransporten von MRSA-positiven Patienten sollte daher der Fokus der Desinfektion auf die Oberflächen in unmittelbarer Patientennähe gelegt werden. Eine weitere Untersuchung von 60 Transporten MRSA-negativer Patienten blieb ohne MRSA-Befund. In 12 dieser Krankentransportwagen wurde jedoch Methicillin-sensibler S. aureus nachgewiesen, der sich ebenfalls vorwiegend an Kopfteil und Handgriffen der Trage fand. Auch dieses Ergebnis unterstreicht die Bedeutung der Desinfektion patientennaher Flächen unabhängig vom MRSA-Status der transportierten Patienten. / Patients carrying MRSA provide a risk of surface contamination with MRSA in ambulance cars. This study analysed whether surfaces of ambulance cars, in which MRSA-colonised or -infected patients were transported, were contaminated with MRSA and where the contamination occurred. 89 transportation events lasting less than 20 minutes were included in the analysis. 8 ambulance cars (7,1%) were found to be contaminated with MRSA following transport (90% confidence interval: 4-14%). The transport time was not relevant for the contamination rate. MRSA was exclusively found on the stretcher, i.e. the headrest and the handles. This finding sug¬gests that disinfection measures after transport should be focused on the patients' contact surfaces. Consecutive investigation included 60 transport events in the absence of MRSA-notification and demonstrated that MSSA, but not MRSA, could be detected in 12 cars, again mostly at handles and headrests. This study shows the importance of disinfection of surfaces in the vicinity of patients transported in an ambulance irrespective of the patients' MRSA-status

Wong, Kai Yi. / Thesis (M.D.)--Chinese University of Hong Kong, 2011. / Includes bibliographical references (leaves 101-110). / Abstracts in English and Chinese. / Abstract --- p.4 / 摘要 --- p.7 / Acknowledgements --- p.9 / List of Tables --- p.10 / List of Figures --- p.11 / List of Abbreviations and Symbols --- p.12 / Chapter Chapter 1 --- Introduction --- p.14 / Chapter 1.1 --- Staphylococcus aureus --- p.14 / Chapter 1.2 --- Methicillin-resistant Staphylococcus aureus (MRSA) --- p.14 / Chapter 1.2.1 --- Methicillin resistance of MRSA --- p.15 / Chapter 1.2.2 --- Staphylococcal Chromosomal Cassette mec (SCCmec) --- p.16 / Chapter 1.2.3 --- Hospital-associated MRSA (HA-MRSA) and Community-associated MRSA (CA-MRSA) --- p.22 / Chapter 1.2.3.1 --- Hospital-associated MRSA (HA-MRSA) --- p.23 / Chapter 1.2.3.2 --- Community-associated MRSA (CA-MRSA) --- p.23 / Chapter 1.2.4 --- Pathogenesis of MRSA infection --- p.27 / Chapter 1.2.4.1 --- Possible virulence genes contributing to necrotizing pneumonia --- p.29 / Chapter 1.2.4.1.1 --- Panton-Valentine Leukocidin (PVL) --- p.29 / Chapter 1.2.4.1.2 --- Phenol-soluble modulins (PSMs) --- p.36 / Chapter 1.3 --- Evolution of MRSA --- p.36 / Chapter 1.4 --- Epidemiology of MRSA --- p.38 / Chapter 1.4.1 --- Epidemiology of MRSA worldwide --- p.38 / Chapter 1.4.1.1 --- Epidemiology of HA-MRSA worldwide --- p.38 / Chapter 1.4.1.2 --- Epidemiology of CA-MRSA worldwide --- p.39 / Chapter 1.4.2 --- Epidemiology of MRSA in Hong Kong --- p.40 / Chapter 1.5 --- Clinical significance of MRSA --- p.41 / Chapter 1.6 --- Antibiotics --- p.43 / Chapter 1.6.1 --- Beta-lactams --- p.43 / Chapter 1.6.2 --- Fluoroquinolone --- p.44 / Chapter 1.6.3 --- Linezolid --- p.45 / Chapter 1.6.4 --- Glycopeptides --- p.45 / Chapter 1.6.5 --- Aminoglycosides --- p.46 / Chapter 1.6.6 --- Fusidic acid --- p.46 / Chapter 1.6.7 --- Clindamycin --- p.47 / Chapter 1.7 --- Hypothesis --- p.47 / Chapter Chapter 2 --- Methods and Materials --- p.50 / Chapter 2.1 --- Bacterial isolate --- p.50 / Chapter 2.2 --- Effect of subinhibitory antibiotics on the expression of mRNA in MRSA in vitro --- p.53 / Chapter 2.2.1 --- Collection of bacterial fraction --- p.53 / Chapter 2.2.2 --- RNA extraction and DNA digestion --- p.53 / Chapter 2.2.3 --- Reverse transcription for cDNA synthesis --- p.54 / Chapter 2.2.4 --- Quantitative real-time PCR (qPCR) analysis (pvl and psma\-A expression) --- p.55 / Chapter 2.2.5 --- Preparation of standard controls for quantification of DNA copy number in qPCR reactions... --- p.58 / Chapter 2.3 --- Effect of subinhibitory concentration of antibiotics on MRSA pneumonia in a murine model --- p.60 / Chapter 2.4 --- Statistical Analysis --- p.62 / Chapter Chapter 3 --- Results --- p.63 / Chapter 3.1 --- Effect of subinhibitory antibiotics on the expression ofmRNA in MRSA in vitro --- p.63 / Chapter 3.2 --- Effect of subinhibitory concentration of antibiotics on MRSA pneumonia in a murine model --- p.74 / Chapter Chapter 4 --- Discussion --- p.80 / Chapter 4.1 --- Effect of subinhibitory antibiotics on the expression of mRNA in MRSA in vitro --- p.81 / Chapter 4.2 --- Effect of subinhibitory concentration of antibiotics on MRSA pneumonia in a murine model --- p.87 / Chapter 4.3 --- Correlation of effects of subinhibitory antibiotics on the expression ofmRNA in MRSA in vitro and on MRSA pneumonia in a murine model --- p.91 / Chapter 4.4 --- Limitations of Study --- p.95 / Chapter 4.5 --- Future Work --- p.95 / Chapter Chapter 5 --- Conclusions --- p.97 / References --- p.99 / Chapter Appendix I- --- Materials and Reagents --- p.109 / Chapter Appendix II- --- Average and standard deviation of the copy number ratio (pvl or psmal-4 copy number/JdiS1 copy number) --- p.111 / Chapter Appendix III- --- In-vivo experimental data for infected control group and seven antibiotic groups --- p.116

published_or_final_version / Community Medicine / Master / Master of Public Health

Philosophiae Doctor - PhD / The emergence of virulent and drug-resistant bacterial strains such as methicillin-resistant Staphylococcus aureus (MRSA) is a global public health burden. The World Health Organization (WHO) has placed MRSA and vancomycin-intermediate-sensitive S. aureus (VISA) and vancomycin-resistant S. aureus (VRSA) on a high global priority pathogens list of antibiotic-resistant bacteria to promote the research and development of novel and effective antibiotic therapeutic rationales. Uncomplicated S. aureus bacteraemia (e.g., mild skin infections) may be treatable with the conventional regimens of antibiotics, but resistance strains of the bacteria (e.g., invasive infections), often persist as a high load of bacterial DNA in blood, and has been linked to increased mortality in world populations, irrespective of country or location. Several lines of evidence imply that combinations of vancomycin (a glycopeptide antibiotic that targets cell wall synthesis) and ß-lactam antibiotics that target the penicillin-binding proteins (PBPs) improve clearance of MRSA bloodstream infections (BSIs).

No description available.

The Problem: Novel community-acquired, non-multiresistant strains of oxacillin- (methicillin-) resistant Staphylococcus aureus (ORSA) have emerged in many parts of the globe. Little is known of the clinical features, the epidemiology, and the antibiotic treatment of these strains. Materials and Methods: A retrospective chart review was performed on patients presenting to Emergency Departments or Dermatology Clinics with staphylococcal infections. Patients were stratified into three groups, non-multiresistant ORSA (NORSA), multiresistant ORSA (MORSA) and oxacillin-susceptible S. aureus, and clinical comparisons made. Strains of NORSA and MORSA were typed using antibiograms, phage typing and pulsed-field gel electrophoresis. Antimicrobial studies were performed to compare different methods of detecting resistance to oxacillin and to non-beta-lactams. Time-kill studies were performed with one drug to explore killing kinetics. The interaction between drug combinations was examined using disk approximation and time-kill methodologies. A single point pharmacodynamic analysis was performed. Results: There was an increase in infections with NORSA, MORSA and OSSA. NORSA strains appeared to be more virulent than OSSA and MORSA strains. NORSA was strongly associated with skin and soft tissue infections and with Polynesians. Most of the NORSA strains were related to New Zealand ????Western Samoan Phage Pattern???? (WSPP) isolates, and unrelated to community-acquired, non-multiresistant MRSA strains from Western Australia. Two patients were found to have British EMRSA-15 strains. NORSA strains were unrelated to MORSA strains. Resistance to rifampicin, fusidic acid, ciprofloxacin and trimethoprim emerged in the time-kill assays. Combinations of antibiotics, particularly with ciprofloxacin, often showed antagonism. Gentamicin, fusidic acid, clindamycin, teicoplanin, vancomycin, and linezolid were predicted to perform well. Ciprofloxacin, erythromycin, doxycycline, flucloxacillin and quinupristin/dalfopristin were predicted to fail. Conclusions: WSPP strains of New Zealand and EMRSA-15 strains from Britain exist in South Western Sydney. These organisms are virulent, and increasing in incidence in several areas of Australia. Antimicrobial treatment of infections with these strains is problematic and requires further study.

Statement of the problem: Methicillin-resistant Staphyloccocus aureus (MRSA) is a pathogen of increasing concern and is associated with higher hospital readmission rates, poorer prognosis, and increased mortality resulting in increasing costs to the Canadian healthcare system.1-13 Institutions have been challenged with developing effective infection control programs to prevent the spread of MRSA. The purpose of this thesis was to examine the clinical and cost-effectiveness of a universal MRSA screening intervention within a large tertiary care facility. Methods of investigation: The retrospective population-based observational study consisted of two periods. In the first period (24 months), patients admitted to the Ottawa Hospital underwent risk factor-based screening. In the second period (20 months), universal MRSA screening was implemented in which all patients were screened for MRSA upon admission. Results: The regression analysis demonstrated that the universal MRSA screening intervention was not effective in reducing the number of nosocomial MRSA cases. The economic analysis estimated that the universal MRSA screening intervention incurred an additional cost of $1.16 million/year with an estimated additional cost per patient screened of $17.76. Conclusions: The universal MRSA screening intervention was not clinically or economically effective. Further research is required to verify/dispute these findings in other settings.

Statement of the problem: Methicillin-resistant Staphyloccocus aureus (MRSA) is a pathogen of increasing concern and is associated with higher hospital readmission rates, poorer prognosis, and increased mortality resulting in increasing costs to the Canadian healthcare system.1-13 Institutions have been challenged with developing effective infection control programs to prevent the spread of MRSA. The purpose of this thesis was to examine the clinical and cost-effectiveness of a universal MRSA screening intervention within a large tertiary care facility. Methods of investigation: The retrospective population-based observational study consisted of two periods. In the first period (24 months), patients admitted to the Ottawa Hospital underwent risk factor-based screening. In the second period (20 months), universal MRSA screening was implemented in which all patients were screened for MRSA upon admission. Results: The regression analysis demonstrated that the universal MRSA screening intervention was not effective in reducing the number of nosocomial MRSA cases. The economic analysis estimated that the universal MRSA screening intervention incurred an additional cost of $1.16 million/year with an estimated additional cost per patient screened of $17.76. Conclusions: The universal MRSA screening intervention was not clinically or economically effective. Further research is required to verify/dispute these findings in other settings.

Introduktion och bakgrund: Methicillinresistenta staphylokockus aureus finns över hela världen och sprids på både sjukhus och i samhället. Sjuksköterskor som arbetar inom hälso- och sjukvård bör vara medvetna om att det förekommer multiresistenta bakterier och ska därför arbeta preventivt mot smittspridning. Syfte: Syftet med denna litteratur studie var att belysa sjuksköterskors erfarenheter att arbeta preventivt mot MRSA-smittspridning i sjukhusmiljö. Metod: Litteraturöversikten hade sin utgångspunkt från det valda ämnesområdet. Artikelsökningarna genomfördes i vedertagna databaser som till exempel PubMed och Cinahl. 15 vetenskapliga artiklar inkluderades till resultatet efter noggrann kvalitetsgranskning och genomgång. Resultat: Områden som identifierades i resultatet var kunskap, basal hygien och kommunikation. Under dessa områdens belystes hinder, möjligheter och erfarenheter av att arbeta preventivt mot smittspridning av MRSA. Diskussion: Det behövs mer kunskap hos sjuksköterskor angående MRSA, vad det är och hur det preventiva arbetet bör gå till. Följsamheten till basalhygien varierar och tiden kan vara ett hinder till följsamhet. Bristande kommunikation uppgavs som en av de faktorer som försvårade det preventiva arbetet. Slutsats: Syftet med litteraturöversikten var att belysa sjuksköterskors erfarenheter av att arbeta preventivt mot MRSA smittspridning i sjukhusmiljö. Om sjuksköterskan har mer kunskap gällande MRSA skulle smittspridningen kunna minska ute i den kliniska verksamheten vilket skulle gagna patientsäkerheten. Bättre kommunikation, mer utbildning samt lägre arbetsbelastning kanske kan vara ett sätt att förbättra det preventiva arbetet mot smittspridning av MRSA.

published_or_final_version / Nursing Studies / Master / Master of Nursing