Blood Culture Positivity, Microbiological Spectrum, and Inflammatory Correlates in Patients Hospitalized with SARS-CoV-2 Infection During the Omicron BA.5 Wave: A Retrospective Cohort Study.

Blood cultures are frequently obtained in hospitalized patients with COVID-19, although the diagnostic yield and clinical meaning of culture positivity vary markedly according to case mix, disease severity, and timing of sampling. Omicron-era data remain comparatively limited. We aimed to characterize blood-culture positivity, pathogen distribution, inflammatory correlates, antimicrobial exposure, and short-term outcomes in a homogeneous cohort hospitalized during the SARS-CoV-2 Omicron BA.5 wave. This retrospective observational study included 395 patients hospitalized with SARS-CoV-2 infection between 12 July and 25 September 2022. Patients were categorized as blood-culture positive when a named bacterial species was recorded and as culture negative when "No growth" was documented. Continuous variables were compared using the Mann-Whitney U test and categorical variables using Fisher's exact or chi-square tests, as appropriate. A parsimonious multivariable logistic regression model was used to explore factors independently associated with blood-culture positivity. Blood cultures were positive in 89/395 patients (22.5%). Gram-positive organisms accounted for 52.8% of positive cultures and Gram-negative organisms for 47.2%. The most frequent isolates were