TABLE 5.

Overall Rates and Prevalence Rate Ratios of Surgical Site Infections (SSI) per 100 Procedures and the Rates of SSI per 100 Procedures Using 3 Definitions of Summer in a Network of 20 Community Hospitals From January 1, 2007, Through December 31, 2012

Organism	SSI cases for summer	Prevalence rate for summer /100 procedures (95% CI)	SSI cases for rest of year	Prevalence rate for rest of year /100 procedures (95% CI)	Prevalence rate ratio (95% CI)	P value
Summer definition: June through August
All SSI	1,219/111,516	1.09 (1.03–1.16)	3,324/329,912	1.01 (0.97–1.04)	1.08 (1.02–1.16)	.01
Summer definition: July through September
All SSI	1,223/109,996	1.11 (1.05–1.17)	3,320/331,432	1.00 (0.97–1.03)	1.11 (1.04–1.19)	.002
Summer definition: June through September
All SSI	1,612/147,363	1.09 (1.04–1.15)	2,931/294,065	1.00 (0.96–1.03)	1.09 (1.03–1.17)	.002