The trends of blood culture contamination and utilization rates in an LMIC tertiary care center from 2010 to 2022: a call for diagnostic stewardship?

OBJECTIVE

At Saint George Hospital University Medical Center in Beirut, Lebanon, we determine (1) annual blood culture (BC) contamination (BCC) and utilization (BCU) rates vs international benchmarks, (2) identify blood culture contaminants, (3) bloodstream infections episodes in patients with and without COVID-19 after the pandemic onset, and (4) any epidemiologic trends in BCC and BCU.

DESIGN

Retrospective observational study.

SETTING

Private tertiary referral center, from January 1, 2010, to December 31, 2022.

METHODS

We define a contaminated BC as the growth of a typical contaminant/skin flora in 1-2/4 BC bottles. We calculate BCC rates as a percentage of the contaminated BC/total BC during the period and BCU rates as the number of BC/1000 patient days (PD).

RESULTS

The average BCU rate of 85.9/1000 PD in 2010-2019 increased to 106.6/1000 PD in 2020-2022. On average, patients with COVID-19 had a higher BCU rate of 185.9/1000 PD, corresponding to an additional 100 blood cultures/1000 PD. The average BCC rate was 7%, ranging from 6% in 2010-2019 to 8% in 2020-2022. We observed the highest BCC rate of 9% in patients with COVID-19, likely due to the higher BCU. The most frequently isolated contaminants were coagulase-negative Staphylococcus (96%), of which 65% were Staphylococcus epidermidis.

CONCLUSION

We saw a multifactorial, persistently elevated rate of BCC over 13 years as unaffected by strict infection control practices. We think that further research targeting a standardized, low BCU rather than inevitable BCC while advocating for diagnostic stewardship of low-middle-income countries is essential, especially where the lack of appropriate resource allocation and awareness are problematic.