Trends in Collection of Microbiological Cultures Across Veterans Affairs Community Living Centers in the United States Over 8 Years.

OBJECTIVES

To describe and evaluate changes in the collection of microbiological cultures across Veterans Affairs (VA) Community Living Centers (CLCs) nationally.

DESIGN

Descriptive study.

SETTING

146 VA CLCs.

PARTICIPANTS

We identified both positive and negative microbiological cultures collected during VA CLC admissions from January 2010 through December 2017.

MEASURES

We measured the average annual percentage change (AAPC) in the rate of cultures collected per 1000 bed days and per admission, overall and stratified by culture type (ie, urine, blood, skin and soft tissue, and respiratory tract). AAPCs were also calculated for the proportion and rate of positive cultures collected, overall and stratified by culture type and organism (ie, Escherichia coli, Proteus mirabilis, Staphylococcus aureus, Enterococcus spp, Pseudomonas aeruginosa, Klebsiella spp, Enterobacter spp, Morganella morganii, Citrobacter spp, Serratia marcescens, and Streptococcus pneumoniae). Joinpoint regression software was used to assess trends and estimate AAPCs and 95% confidence intervals (CIs).

RESULTS

Over 8 years, 355,329 cultures were collected. The rate of cultures collected per 1000 bed days of care decreased significantly by 6.0% per year (95% CI -8.7%, -3.2%). The proportion of positive cultures decreased by 0.9% (95% CI -1.4%, -0.4%). The most common culture types were urine (48.4%), followed by blood (27.7%). The rate of cultures collected per 1000 bed days of care decreased per year by 6.3% for urine, 5.0% for blood, 4.4% for skin and soft tissue, and 4.9% for respiratory tract. In 2010, S aureus was the most common organism identified, and in all subsequent years E coli was the most common.

CONCLUSION AND IMPLICATIONS

We identified a significant reduction in the number of cultures collected over time among VA CLCs. Our findings may be explained by decreases in the collection of unnecessary cultures in VA CLCs nationally due to increased antibiotic stewardship efforts targeting unnecessary culturing and antibiotic treatment.