Biomedicine: 2023; 43(2): 722-727 March-April 2023 DOI: https://doi.org/10.51248/.v43i02.2464 Biomedicine- Vol. 43 No. 2: 2023 Research article Blood culture and profile of inflammatory biomarkers among COVID-19 patients in an intensive care unit of a tertiary care hospital Asif P.P., Rouchelle C. Tellis., Amar Sunil Lobo., Aravind Motagi Department of Microbiology, Yenepoya Medical College, Yenepoya (Deemed to be University), Mangaluru 575018, Karnataka, India (Received: January 2023 Revised: March 2023 Accepted: April 2023) Corresponding author: Rouchelle C. Tellis; Aravind Motagi. Email: rctellis123@gmail.com ABSTRACT Introduction and Aim: This is a retrospective study to analyse the pathogens causing bacteraemia in COVID-19 patients and its correlation with inflammatory biomarkers such as procalcitonin (PCT), C-reactive protein (CRP), total WBC counts (TC) and D-dimer. The objectives of this study were to evaluate the blood culture positivity rate, to identify the pathogens causing bacteraemia, to analyse their antibiogram and to assess the significance of inflammatory markers along with patient outcomes. Materials and Methods: This study included 165 COVID-19-positive patients admitted to the Intensive care unit (ICU) of a tertiary care hospital from June to September 2020. Blood culture, identification and antibiotic sensitivity testing (AST) were done using automated systems. Values of D-dimer, CRP, PCT and TC were obtained using immunoturbidimetric assay, chemiluminescent immunoassay, immunochromatographic testing and automated haematology analyser respectively. Results: Among 143 blood culture samples obtained from 122 COVID-19 positive patients, 80 flagged positive. Out of the 80 isolates obtained, 53 (66.25%), 17 (21.25%) and 10 (12.5%) were gram-positive bacteria, gram- negative bacteria and candida respectively. The blood culture positivity rate was 25.4%. Acinetobacter spp. and K. pneumoniae showed high levels of antibiotic resistance. Among 16 patients with elevated PCT, 15 (93.7%) patients showed positive blood cultures. CRP of >5 mg/L and deranged total WBC counts were seen among all blood culture-positive patients. In 100 patients with elevated D-dimer, 54% (54/100) patients showed positive blood culture. Conclusion: From this study, we conclude that early identification of pathogens and initiation of appropriate antimicrobial therapy is crucial for managing sepsis associated with COVID-19 infection. PCT, CRP, TC and D- dimer can help as biomarkers in the management of COVID-19 patients with secondary bloodstream infections (BSI). Keywords: COVID-19; bloodstream infection; blood culture; CRP; procalcitonin. INTRODUCTION OVID-19 represents a spectrum of clinical severity ranging from asymptomatic to severe pneumonia, acute respiratory distress syndrome (ARDS), and even death. Monitoring the severity and effective early intervention are the fundamental measures for reducing mortality (1). Severe COVID-19 infections are often associated with bacterial co-infections and several studies suggest the use of empirical antibiotics in severely ill patients (2- 4). Studies suggest that inflammatory markers are elevated in patients with severe disease admitted to the intensive care units (5-8). Therefore, it is important to identify the bacterial agents causing secondary bloodstream infections (BSI) and estimate the potential biomarkers for the effective and appropriate treatment of these patients. As the prevalence, etiological agents, and antibiotic sensitivity profile of bacteria causing secondary BSI in COVID-19 patients is not very well understood, the present study was carried out with an aim to analyse the etiological agents causing bacteraemia in these patients and its correlation with inflammatory biomarkers such as procalcitonin (PCT), C-reactive protein (CRP), total WBC counts (TC) and D-dimer. The objectives of this study were to evaluate the blood culture positivity rate, to assess the distribution and antibiogram of pathogens obtained from blood cultures and to understand the association of blood culture positivity with inflammatory markers and disease outcome. MATERIALS AND METHODS This is a retrospective laboratory-based observational study that included 165 COVID-19-positive patients admitted to the ICU of tertiary care hospital in South India from June to September 2020. After obtaining due approval from the Institutional Ethical Committee, clinical and laboratory data of the patients was accessed from the hospital's electronic medical records archives. Blood culture samples were sent from 122 of these patients and incubated using an automated blood culture system (BD BACTEC 9120) for a maximum period of 5 days. Identification and antibiotic sensitivity testing (AST) of the bacterial isolates was C 722