Seasonal Increases in Gram-Negative Bacterial Bloodstream Infections
Author Information
Author(s): Eber Michael R., Shardell Michelle, Schweizer Marin L., Laxminarayan Ramanan, Perencevich Eli N.
Primary Institution: Center for Disease Dynamics, Economics and Policy
Hypothesis
Are bloodstream infections caused by Gram-negative bacteria more frequent in summer months compared to winter months?
Conclusion
Summer season and higher mean monthly outdoor temperature are associated with substantially increased frequency of bloodstream infections, particularly among clinically important Gram-negative bacteria.
Supporting Evidence
- BSIs caused by Gram-negative organisms were more frequent in summer months compared to winter months.
- Acinetobacter showed a 51.8% increase in BSI frequency in summer.
- E. coli BSIs were 12.2% more frequent in summer relative to winter.
- Higher mean monthly temperature was associated with increased frequencies of BSIs.
Takeaway
In the summer, more people in hospitals get infections from certain bacteria, especially when it's warmer outside.
Methodology
The study analyzed blood cultures from 132 U.S. hospitals over 9,423 hospital-months, examining associations with temperature, precipitation, and humidity.
Potential Biases
Potential non-weather-related seasonal factors could affect the results, such as differences in infection control practices.
Limitations
The study could not measure the populations of each institution over time, which may affect the accuracy of infection incidence rates.
Participant Demographics
Data collected from 132 hospitals across all nine U.S. census regions.
Statistical Information
Confidence Interval
95% CI
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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