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Experimental Endocarditis Model of Methicillin Resistant Staphylococcus aureus (MRSA) in Rat
Published on: June 4, 2012
Methicillin-resistant Staphylococcus aureus bloodstream infection: risk factors and clinical outcome in
Karinne Spirandelli Carvalho Naves1, Natália Vaz da Trindade, Paulo Pinto Gontijo Filho
1Programa de Pós-Graduação em Imunologia e Parasitologia Aplicadas, Instituto de Ciências Biomédicas, Universidade Federal de Uberlândia, Uberlândia, MG. kscnaves@icbim.ufu.br
Introduction:
Methicillin-resistant Staphylococcus aureus (MRSA) is spread out in hospitals across different regions of the world and is regarded as the major agent of nosocomial infections, causing infections such as skin and soft tissue pneumonia and sepsis. The aim of this study was to identify risk factors for methicillin-resistance in Staphylococcus aureus bloodstream infection (BSI) and the predictive factors for death.
Methods:
A retrospective cohort of fifty-one patients presenting bacteraemia due to S. aureus between September 2006 and September 2008 was analysed. Staphylococcu aureus samples were obtained from blood cultures performed by clinical hospital microbiology laboratory from the Uberlândia Federal University. Methicillinresistance was determined by growth on oxacillin screen agar and antimicrobial susceptibility by means of the disk diffusion method.
Results:
We found similar numbers of MRSA (56.8%) and methicillin-susceptible Staphylococcus aureus (MSSA) (43.2%) infections, and the overall hospital mortality ratio was 47%, predominantly in MRSA group (70.8% vs. 29.2%) (p=0.05). Age (p=0.02) was significantly higher in MRSA patients as also was the use of central venous catheter (p=0.02). The use of two or more antimicrobial agents (p=0.03) and the length of hospital stay prior to bacteraemia superior to seven days (p=0.006) were associated with mortality. High odds ratio value was observed in cardiopathy as comorbidity.
Conclusions:
Despite several risk factors associated with MRSA and MSSA infection, the use of two or more antimicrobial agents was the unique independent variable associated with mortality.
Insights
Methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible Staphylococcus aureus (MSSA) bloodstream infections show similar prevalence. The use of multiple antimicrobial agents is the sole independent predictor of mortality in these infections.
Area of Science:
- Infectious Diseases
- Clinical Microbiology
- Epidemiology
Background:
- Methicillin-resistant Staphylococcus aureus (MRSA) is a leading cause of hospital-acquired infections globally.
- MRSA causes severe conditions including pneumonia, sepsis, and skin/soft tissue infections.
- Understanding risk factors and mortality predictors for Staphylococcus aureus bloodstream infections (BSI) is crucial.
Purpose of the Study:
- To identify risk factors associated with MRSA bloodstream infections.
- To determine predictive factors for mortality in patients with Staphylococcus aureus BSI.
Main Methods:
- Retrospective cohort study of 51 patients with S. aureus bacteremia (Sept 2006 - Sept 2008).
- Samples analyzed via blood cultures; MRSA identified using oxacillin screen agar.
- Antimicrobial susceptibility determined by disk diffusion method.
Main Results:
- Similar prevalence of MRSA (56.8%) and MSSA (43.2%) infections.
- Overall hospital mortality was 47%, higher in MRSA patients (70.8%).
- Increased age and central venous catheter use were linked to MRSA; multiple antibiotics and prolonged hospital stay (>7 days) predicted mortality.
Conclusions:
- Several risk factors are associated with MRSA and MSSA infections.
- The use of two or more antimicrobial agents was the only independent predictor of mortality.
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