Annals of Clinical Microbiology, The official Journal of the Korean Society of Clinical Microbiology


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pISSN 2288-0585 eISSN 2288-6850

Season and Temperature Effects on Bloodstream Infection Incidence in a Korean Tertiary Referral Hospital

Original article

Annals of Clinical Microbiology (Ann Clin Microbiol) 2020 March, 23(1): 33-43

Season and Temperature Effects on Bloodstream Infection Incidence in a Korean Tertiary Referral Hospital

Young Suk Sohn1, Jung-Hyun Byun2, Young Ah Kim3, Dong Chun Shin4, Kyungwon Lee1
1Department of Laboratory Medicine, Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, 2Department of Laboratory Medicine, Gyeongsang National University Hospital, Gyeongsang National University College of Medicine, Jinju, 3Department of Laboratory Medicine, National Health Insurance Service Ilsan Hospital, Goyang, 4Department of Environmental Health Graduate School of Public Health, Yonsei University, Seoul, Korea


Background: The weather has well-documented effects on infectious disease and reports suggest that summer peaks in the incidences of gram-negative bacterial infections among hospitalized patients. We evaluated how season and temperature changes affect bloodstream infection (BSI) incidences of major pathogens to understand BSI trends with an emphasis on acquisition sites.

Methods: Incidence rates of BSIs by Staphylococcus aureus, Enterococcus spp., Escherichia coli, Klebsiella pneumoniae, Acinetobacter spp., and Pseudomonas aeruginosa were retrospectively analyzed from blood cultures during 2008–2016 at a university hospital in Seoul, Korea according to the acquisition sites. Warm months (June–September) had an average temperature of ≥20 °C and cold months (December–February) had an average temperature of ≤5 °C.

Results: We analyzed 18,047 cases, where 43% were with community-onset BSI. E. coli (N = 5,365) was the most common pathogen, followed by Enterococcus spp. (N = 3,980), S. aureus (N = 3,075), K. pneumoniae (N = 3,043), Acinetobacter spp. (N = 1,657), and P. aeruginosa (N = 927). The incidence of hospital-acquired BSI by Enterococcus spp. was weakly correlated with temperature, and the median incidence was higher during cold months. The incidence of community-onset BSI by E. coli was higher in warm months and was weakly correlated with temperature.

Conclusion: We found seasonal or temperature-associated variation in some speciesassociated BSIs. This could be a useful information for enhancing infection control and public health policies by taking season or climate into consideration.


Bloodstream infection, Climate change, Incidence, Seasonality