Seasonality of MRSA Infections

Leonard A Mermel,Jason T Machan,Stephen Parenteau,Frank Deleo

doi:10.1371/journal.pone.0017925

Leonard A Mermel, Jason T Machan + Show 2 more

Open Access

https://doi.org/10.1371/journal.pone.0017925

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Journal: PloS one	Publication Date: Mar 23, 2011
Citations: 86	License type: CC BY 4.0

Affiliation: Rhode Island Hospital, Brown University, Providence College

Abstract

Using MRSA isolates submitted to our hospital microbiology laboratory January 2001–March 2010 and the number of our emergency department (ED) visits, quarterly community-associated (CA) and hospital-associated (HA) MRSA infections were modeled using Poisson regressions. For pediatric patients, approximately 1.85x (95% CI 1.45x–2.36x, adj. p<0.0001) as many CA-MRSA infections per ED visit occurred in the second two quarters as occurred in the first two quarters. For adult patients, 1.14x (95% CI 1.01x–1.29x, adj.p = 0.03) as many infections per ED visit occurred in the second two quarters as in the first two quarters. Approximately 2.94x (95% CI 1.39x–6.21x, adj.p = 0.015) as many HA-MRSA infections per hospital admission occurred in the second two quarters as occurred in the first two quarters for pediatric patients. No seasonal variation was observed among adult HA-MRSA infections per hospital admission. We demonstrated seasonality of MRSA infections and provide a summary table of similar observations in other studies.

Highlights

Seasonal variation in Staphylococcus aureus infections is controversial
A mean of approximately 1.85x as many community-associated methicillin-resistant S. aureus (CA-MRSA) infections per emergency department (ED) visit occurred in the second two quarters as occurred in the first two quarters over the study period
This reflected greater seasonal variation than we observed among adult Hospital-associated MRSA (HA-MRSA) infections per hospital admission, in which the second two quarters did not differ from the first two quarters, 1.00x

Summary

Introduction

Seasonal variation in Staphylococcus aureus infections is controversial. Some studies have demonstrated a highly significant surge of such infections during the warmest months and during autumn in temperate and tropical settings [1,2,3]. A recent study did not find such a correlation [4]. We have observed peaks of community-associated methicillin-resistant S. aureus (CA-MRSA) infections during the summer and autumn and we set out to determine if there is a correlation between MRSA infections in patients of all ages and seasonality

Results

Discussion

Methods