Min Gu,1,2,* Xiaohui Zhang,1,2,* Fang Ni,1,2 Jue Wang,1,2 Wenying Xia,1,2 Yanfei Lu1,2 

1Department of Laboratory Medicine, Jiangsu Province Hospital and Nanjing Medical University First Affiliated Hospital, Nanjing, People’s Republic of China; 2National Key Clinical Department of Laboratory Medicine, Nanjing, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Yanfei Lu; Wenying Xia, Department of Laboratory Medicine, Jiangsu Province Hospital, Street No. 300, Guangzhou, 210029, People’s Republic of China, Tel +8625-6830-6287, Email 549793546@qq.com; xiawenying21106891@163.com

Purpose: To explore the characteristics of the pathogen distribution and drug resistance in bloodstream infections (BSIs) during the COVID-19 pandemic in a tertiary hospital in eastern China, and to compare them with those before the pandemic.
Patients and Methods: Non-repetitive strain data of BSIs were retrospectively obtained before the COVID-19 pandemic (Pre-Pandemic, n=2698) and during the COVID-19 pandemic (Pandemic, n=2922), the distribution of pathogens and drug resistance were compared between the two groups.
Results: The main pathogens of BSIs were Gram-negative bacteria (57.91%), followed by Gram-positive bacteria (32.58%), fungi and anaerobic bacteria accounting for 5.48% and 3.39%, respectively. Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus were the top 3 isolates. The proportion of Serratia marcescens, Enterobacter aerogenes, Enterococcus faecium, Enterococcus faecalis and Candida tropicalis were significantly increased, while those of Pseudomonas aeruginosa, Streptococcus sanguinis and Streptococcus pneumoniae were significantly decreased when compared to the Pre-Pandemic (P< 0.05). Carbapenem-resistant Enterobacterales (CRE) significantly elevated during the Pandemic (17.4% vs 14.4%, P=0.041); the detection of carbapenem-resistant Pseudomonas aeruginosa (CRPA) significantly ascended (39.0% vs 24.4%, P=0.016); and the proportion of carbapenem-resistant Acinetobacter baumannii (CRAB) maintained stable (78.8%). Gram-positive bacteria had the lowest resistance to linezolid, vancomycin and tigecycline, which remained a stable trend with the Pre-Pandemic (< 5.0%). The isolate rates of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) were 38.9% and 1.0%, respectively. Staphylococcus aureus showed a decrease in the isolation rate of vancomycin minimum inhibitory concentration (MIC) ≤ 0.5 μg/mL (χ 2=7.676, P=0.006) and an increase with vancomycin MIC=1 μg/mL (χ 2=9.008, P=0.003).
Conclusion: The pathogen distribution and drug resistance of BSIs during the COVID-19 pandemic were transformed from Pre-Pandemic and accompanied by increasing bacterial resistance. Clinical management of antibiotic application and infection control should be strengthened.

Keywords: COVID-19 pandemic, bloodstream infection, pathogen distribution, antibiotic resistance