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Subcutaneous Infection of Methicillin Resistant Staphylococcus Aureus MRSA
Published on: February 9, 2011
Clonal complex 398 methicillin-susceptible Staphylococcus aureus bloodstream infections are associated with high
K Bouiller1, H Gbaguidi-Haore2, D Hocquet2
1Maladies infectieuses, Centre Hospitalier Régional Universitaire, Besançon, France.
Abstract:
Within the last decade, methicillin-resistant Staphylococcus aureus belonging to clonal complex 398 (CC398) has become a worldwide threat associated with livestock. More recently, methicillin-susceptible S. aureus (MSSA) belonging to CC398 have been increasingly reported as a cause of invasive infections in patients without livestock contact. We investigated risk factors associated with CC398 bloodstream infections (BSIs) compared with non-CC398 BSIs with a case-control study in a French university Hospital. From January 2010 to December 2014, nonduplicate Staphylococcus aureus (SA) isolates responsible for BSIs in adult patient were typed to identify those belonging to CC398. Each adult patient with a CC398 SA BSI (cases) was matched with 2 non-CC398 SA BSI controls randomly selected on the basis of the time at risk, the unit of hospitalization and susceptibility to methicillin. We retrospectively extracted the clinical information from electronic medical records and used conditional logistic regression for univariate and multivariate analyses. We identified 67 CC398 isolates among the 770 SA responsible for BSI in adult patients. All CC398 isolates were susceptible to methicillin. The proportion of CC398 among MSSA increased steadily from 4.6% in 2010 to 15.1% in 2013 and then stabilized at 13.8% in 2014. Factors significantly associated with CC398 MSSA BSIs were healthcare-associated infection (odds ratio (OR) 3.02, 95% confidence interval (CI) 1.19-7.63), history of neurologic disease (OR 2.51, 95% CI 1.13-5.65) and 30-day mortality (OR 2.44, 95% CI 1.23-4.85).
Insights
Methicillin-susceptible Staphylococcus aureus (MSSA) CC398 bloodstream infections (BSIs) are rising in patients without livestock contact. Healthcare-associated infections and a history of neurologic disease were significant risk factors for CC398 MSSA BSIs.
Area of Science:
- Medical Microbiology
- Infectious Diseases
- Epidemiology
Background:
- Clonal complex 398 (CC398) Staphylococcus aureus (S. aureus), initially known for livestock-associated methicillin-resistant strains, is increasingly implicated in human infections.
- Methicillin-susceptible S. aureus (MSSA) CC398 isolates are emerging as a cause of invasive infections, even in individuals without direct livestock exposure.
Purpose of the Study:
- To investigate the risk factors associated with bloodstream infections (BSIs) caused by methicillin-susceptible S. aureus CC398 (CC398 MSSA) compared to non-CC398 BSIs.
- To analyze the epidemiological trends and clinical characteristics of CC398 MSSA BSIs in a French university hospital.
Main Methods:
- A case-control study was conducted involving adult patients with S. aureus BSIs between January 2010 and December 2014.
- CC398 isolates were identified, and cases (CC398 MSSA BSI) were matched with two controls (non-CC398 MSSA BSI) based on time, unit, and methicillin susceptibility.
- Conditional logistic regression was used for univariate and multivariate analyses of clinical data extracted from electronic medical records.
Main Results:
- Out of 770 S. aureus BSIs, 67 were identified as CC398, all susceptible to methicillin.
- The proportion of CC398 among MSSA BSIs increased from 4.6% in 2010 to 15.1% in 2013, stabilizing at 13.8% in 2014.
- Significant risk factors for CC398 MSSA BSIs included healthcare-associated infection (OR 3.02), a history of neurologic disease (OR 2.51), and 30-day mortality (OR 2.44).
Conclusions:
- Methicillin-susceptible S. aureus CC398 is an emerging pathogen causing BSIs in hospitalized patients, independent of livestock contact.
- Healthcare-associated infections and pre-existing neurologic conditions are key risk factors for CC398 MSSA BSIs.
- The findings highlight the evolving epidemiology of S. aureus CC398 and the need for targeted surveillance and infection control strategies.
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