{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T09:24:46Z","timestamp":1788341086346,"version":"build-2803163510"},"reference-count":42,"publisher":"MDPI AG","issue":"9","license":[{"start":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T00:00:00Z","timestamp":1788307200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Victor Babe\u0219 University of Medicine and Pharmacy Timi\u0219oara"},{"id":[{"id":"https:\/\/ror.org\/00afdp487","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>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 \u201cNo growth\u201d was documented. Continuous variables were compared using the Mann\u2013Whitney U test and categorical variables using Fisher\u2019s 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 Streptococcus pneumoniae (20.2% of positive cultures), Enterococcus faecalis (18.0%), Klebsiella pneumoniae (18.0%), Staphylococcus aureus (14.6%), Escherichia coli (14.6%), and Pseudomonas aeruginosa (14.6%). Compared with patients with no growth, those with positive cultures had higher admission leukocyte counts (median 13.42 vs. 11.22 \u00d7 109\/L; p &lt; 0.001), C-reactive protein (116.15 vs. 105.50; p = 0.007), and interleukin-6 (17.24 vs. 9.39; p = 0.027). A documented sepsis diagnosis was more frequent in the culture-positive group (48.3% vs. 28.1%; OR 2.39, 95% CI 1.47\u20133.88; p &lt; 0.001). Mortality was numerically higher with culture positivity (20.2% vs. 14.4%) but did not reach statistical significance (p = 0.188). In the adjusted model, higher leukocyte count remained independently associated with culture positivity (aOR 1.10 per 1 \u00d7 109\/L, 95% CI 1.05\u20131.15; p &lt; 0.001), while vaccination status showed an inverse exploratory association (aOR 0.58, 95% CI 0.35\u20130.96; p = 0.033). The exploratory model AUC was 0.672 (bootstrap 95% CI 0.608\u20130.731); calibration was not assessed. Blood-culture positivity was common in this hospitalized BA.5 cohort and showed a nearly balanced Gram-positive\/Gram-negative distribution. Leukocytosis and clinically documented sepsis were the clearest correlates of positivity, whereas mortality did not differ significantly. These findings support selective blood-culture use driven by bacterial infection signals and emphasize the need to connect antimicrobial decisions to microbiological evidence.<\/jats:p>","DOI":"10.3390\/microorganisms14091941","type":"journal-article","created":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T08:56:01Z","timestamp":1788339361000},"page":"1941","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["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"],"prefix":"10.3390","volume":"14","author":[{"ORCID":"https:\/\/orcid.org\/0009-0005-2467-9091","authenticated-orcid":false,"given":"Cristiana Georgeta","family":"Bujor","sequence":"first","affiliation":[{"name":"Department IV\u2014Biochemistry and Pharmacology, Faculty of Medicine, \u201cVictor Babe\u015f\u201d University of Medicine and Pharmacy Timi\u0219oara, Eftimie Murgu Square 2, 300041 Timi\u0219oara, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Marilena","family":"Dinuti","sequence":"additional","affiliation":[{"name":"Department IV\u2014Biochemistry and Pharmacology, Faculty of Medicine, \u201cVictor Babe\u015f\u201d University of Medicine and Pharmacy Timi\u0219oara, Eftimie Murgu Square 2, 300041 Timi\u0219oara, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Felicia","family":"Sfrijan","sequence":"additional","affiliation":[{"name":"Department IV\u2014Biochemistry and Pharmacology, Faculty of Medicine, \u201cVictor Babe\u015f\u201d University of Medicine and Pharmacy Timi\u0219oara, Eftimie Murgu Square 2, 300041 Timi\u0219oara, Romania"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"e00875-20","DOI":"10.1128\/JCM.00875-20","article-title":"Bacteremia and blood culture utilization during COVID-19 surge in New York City","volume":"58","author":"Sepulveda","year":"2020","journal-title":"J. Clin. Microbiol."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Yu, D., Ininbergs, K., Hedman, K., Giske, C.G., Str\u00e5lin, K., and \u00d6zenci, V. (2020). Low prevalence of bloodstream infection and high blood culture contamination rates in patients with COVID-19. PLoS ONE, 15.","DOI":"10.1371\/journal.pone.0242533"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"ofaa578","DOI":"10.1093\/ofid\/ofaa578","article-title":"Prevalence of co-infection at the time of hospital admission in COVID-19 patients: A multicenter study","volume":"8","author":"Karaba","year":"2021","journal-title":"Open Forum Infect. Dis."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1622","DOI":"10.1016\/j.cmi.2020.07.016","article-title":"Bacterial co-infection and secondary infection in patients with COVID-19: A living rapid review and meta-analysis","volume":"26","author":"Langford","year":"2020","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"319","DOI":"10.23736\/S2724-606X.21.04878-8","article-title":"What may happen if you are pregnant during COVID-19 lockdown? A retrospective study about peripartum outcomes","volume":"74","author":"Amadori","year":"2022","journal-title":"Minerva Obstet. Gynecol."},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Di Lorenzo, P., Casella, C., Marisei, M., Sarno, L., Aquino, C.I., Osuna, E., Guida, M., and Niola, M. (2023). A COVID dilemma: How to manage pregnancies in case of severe respiratory failure?. Healthcare, 11.","DOI":"10.3390\/healthcare11040486"},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Ippolito, M., Simone, B., Filisina, C., Catalanotto, F.R., Catalisano, G., Marino, C., Misseri, G., Giarratano, A., and Cortegiani, A. (2021). Bloodstream infections in hospitalized patients with COVID-19: A systematic review and meta-analysis. Microorganisms, 9.","DOI":"10.3390\/microorganisms9102016"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"1395","DOI":"10.1016\/j.cmi.2020.06.025","article-title":"Bacterial and fungal coinfection among hospitalized patients with COVID-19: A retrospective cohort study in a UK secondary-care setting","volume":"26","author":"Hughes","year":"2020","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1017\/ice.2020.368","article-title":"Bacterial and fungal coinfections in COVID-19 patients hospitalized during the New York City pandemic surge","volume":"42","author":"Nori","year":"2021","journal-title":"Infect. Control Hosp. Epidemiol."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"e13319","DOI":"10.1111\/eci.13319","article-title":"Bloodstream infections in critically ill patients with COVID-19","volume":"50","author":"Giacobbe","year":"2020","journal-title":"Eur. J. Clin. Investig."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"e995","DOI":"10.1093\/cid\/ciaa1748","article-title":"Risk factors and outcomes of hospitalized patients with severe COVID-19 and secondary bloodstream infections: A multicenter case-control study","volume":"72","author":"Bhatt","year":"2021","journal-title":"Clin. Infect. Dis."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"180","DOI":"10.1007\/s00134-021-06346-w","article-title":"COVID-19 increased the risk of ICU-acquired bloodstream infections: A case-cohort study from the multicentric OUTCOMEREA network","volume":"47","author":"Buetti","year":"2021","journal-title":"Intensive Care Med."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"451","DOI":"10.1016\/j.cmi.2020.10.021","article-title":"Secondary infections in patients hospitalized with COVID-19: Incidence and predictive factors","volume":"27","author":"Ripa","year":"2021","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"ofab339","DOI":"10.1093\/ofid\/ofab339","article-title":"Hospital-acquired bloodstream infections in patients hospitalized with severe acute respiratory syndrome coronavirus 2 infection (coronavirus disease 2019): Association with immunosuppressive therapies","volume":"8","author":"Khatri","year":"2021","journal-title":"Open Forum Infect. Dis."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"520","DOI":"10.1016\/j.cmi.2020.12.018","article-title":"Antibiotic prescribing in patients with COVID-19: Rapid review and meta-analysis","volume":"27","author":"Langford","year":"2021","journal-title":"Clin. Microbiol. Infect."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"935","DOI":"10.1007\/s15010-021-01615-8","article-title":"C-reactive protein and procalcitonin for antimicrobial stewardship in COVID-19","volume":"49","author":"Pink","year":"2021","journal-title":"Infection"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"570","DOI":"10.1017\/ice.2021.175","article-title":"The role of procalcitonin results in antibiotic decision-making in coronavirus disease 2019 (COVID-19)","volume":"43","author":"Fabre","year":"2022","journal-title":"Infect. Control Hosp. Epidemiol."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"e179","DOI":"10.1016\/S2666-5247(22)00355-X","article-title":"Antimicrobial resistance in patients with COVID-19: A systematic review and meta-analysis","volume":"4","author":"Langford","year":"2023","journal-title":"Lancet Microbe"},{"key":"ref_19","doi-asserted-by":"crossref","unstructured":"Mateescu, D.-M., Ilie, A.-C., Cotet, I., Guse, C., Muresan, C.-O., Pah, A.-M., Badalica-Petrescu, M., Iurciuc, S., Craciun, M.-L., and Avram, A. (2025). Global burden of bloodstream infections in COVID-19: Prevalence, antimicrobial resistance, and mortality risk. Viruses, 17.","DOI":"10.20944\/preprints202508.0812.v1"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1453","DOI":"10.1016\/S0140-6736(07)61602-X","article-title":"The Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) statement: Guidelines for reporting observational studies","volume":"370","author":"Altman","year":"2007","journal-title":"Lancet"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"183","DOI":"10.1186\/s13613-021-00971-w","article-title":"Characteristics and prognosis of bloodstream infection in patients with COVID-19 admitted in the ICU: An ancillary study of the COVID-ICU study","volume":"11","author":"Massart","year":"2021","journal-title":"Ann. Intensive Care"},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2588","DOI":"10.3201\/eid2710.210538","article-title":"Bloodstream Infection Risk, Incidence, and Deaths for Hospitalized Patients during Coronavirus Disease Pandemic","volume":"27","author":"Shukla","year":"2021","journal-title":"Emerg. Infect. Dis."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"e31","DOI":"10.1097\/CCM.0000000000004748","article-title":"Unexpectedly high frequency of enterococcal bloodstream infections in coronavirus disease 2019 patients admitted to an Italian ICU: An observational study","volume":"49","author":"Bonazzetti","year":"2021","journal-title":"Crit. Care Med."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"319","DOI":"10.1186\/s13054-022-04166-y","article-title":"Different epidemiology of bloodstream infections in COVID-19 compared to non-COVID-19 critically ill patients: A descriptive analysis of the Eurobact II study","volume":"26","author":"Buetti","year":"2022","journal-title":"Crit. Care"},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Wang, J., and Jiang, T. (2025). Risk factors for bloodstream infection in COVID-19 patients in intensive care units: A systematic review and meta-analysis. BMC Infect. Dis., 25.","DOI":"10.1186\/s12879-024-10420-1"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"e1082","DOI":"10.1093\/cid\/ciab869","article-title":"Changing patterns of bloodstream infections in the community and acute care across two COVID-19 epidemic waves: A retrospective analysis using data linkage","volume":"75","author":"Zhu","year":"2022","journal-title":"Clin. Infect. Dis."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Slabisz, N., Dudek-Wicher, R., Lesnik, P., Majda, J., Kujawa, K., and Nawrot, U. (2023). Impact of the COVID-19 pandemic on the epidemiology of bloodstream infections in hospitalized patients-experience from a 4th Military Clinical Hospital in Poland. J. Clin. Med., 12.","DOI":"10.3390\/jcm12185942"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"e0263023","DOI":"10.1128\/spectrum.02630-23","article-title":"The impact of the COVID-19 pandemic on blood culture practices and bloodstream infections","volume":"11","author":"Driedger","year":"2023","journal-title":"Microbiol. Spectr."},{"key":"ref_29","doi-asserted-by":"crossref","unstructured":"Pintea-Simon, I.-A., Bancu, L., Mare, A.D., Ciurea, C.N., Toma, F., Brukner, M.C., Vasiesiu, A.-M., and Man, A. (2024). Secondary bacterial infections in critically ill COVID-19 patients admitted in the intensive care unit of a tertiary hospital in Romania. J. Clin. Med., 13.","DOI":"10.3390\/jcm13206201"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1965","DOI":"10.21873\/invivo.13653","article-title":"Bloodstream coinfections and antimicrobial resistance in hospitalized COVID-19 patients: A single-center retrospective study","volume":"38","author":"Tsai","year":"2024","journal-title":"In Vivo"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1016\/j.jointm.2023.12.004","article-title":"Bloodstream infections in the era of the COVID-19 pandemic: Changing epidemiology of antimicrobial resistance in the intensive care unit","volume":"4","author":"Ntziora","year":"2024","journal-title":"J. Intensive Med."},{"key":"ref_32","doi-asserted-by":"crossref","unstructured":"Montrucchio, G., Grillo, F., Balzani, E., Gavanna, G., Sales, G., Bonetto, C., Simonetti, U., Zanierato, M., Fanelli, V., and Filippini, C. (2025). Impact of multidrug-resistant bacteria in a cohort of COVID-19 critically ill patients: Data from a prospective observational study conducted in a high-antimicrobial-resistance-prevalence center. J. Clin. Med., 14.","DOI":"10.3390\/jcm14020410"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1016\/j.jaci.2020.05.008","article-title":"Elevated levels of IL-6 and CRP predict the need for mechanical ventilation in COVID-19","volume":"146","author":"Herold","year":"2020","journal-title":"J. Allergy Clin. Immunol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1002\/rmv.2141","article-title":"Interleukin-6 in COVID-19: A systematic review and meta-analysis","volume":"30","author":"Coomes","year":"2020","journal-title":"Rev. Med. Virol."},{"key":"ref_35","doi-asserted-by":"crossref","unstructured":"Mateescu, D.-M., Ilie, A.-C., Cotet, I., Muresan, C.-O., Pah, A.-M., Badalica-Petrescu, M., Iurciuc, S., Craciun, M.-L., Cote, A., and Enache, A. (2025). Predicting COVID-19 sepsis outcomes: Roles of IL-6, cardiac biomarkers, clinical factors, and vaccination status and exploratory analysis of tocilizumab therapy in an Eastern European cohort. Viruses, 17.","DOI":"10.20944\/preprints202507.2097.v1"},{"key":"ref_36","doi-asserted-by":"crossref","unstructured":"Mateescu, D.-M., Cotet, I., Guse, C., Prodan-Barbulescu, C., Varga, N.-I., Iurciuc, S., Craciun, M.-L., Ilie, A.-C., and Enache, A. (2025). Predictors of unfavorable outcomes in COVID-19-related sepsis: A prospective cohort study. Viruses, 17.","DOI":"10.3390\/v17040455"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"801","DOI":"10.1001\/jama.2016.0287","article-title":"The Third International Consensus Definitions for Sepsis and Septic Shock (Sepsis-3)","volume":"315","author":"Singer","year":"2016","journal-title":"JAMA"},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"2042","DOI":"10.1097\/CCM.0000000000005195","article-title":"Coronavirus disease 2019 as cause of viral sepsis: A systematic review and meta-analysis","volume":"49","author":"Karakike","year":"2021","journal-title":"Crit. Care Med."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"e354","DOI":"10.1016\/S2666-5247(21)00090-2","article-title":"Co-infections, secondary infections, and antimicrobial use in patients hospitalised with COVID-19 during the first pandemic wave from the ISARIC WHO CCP-UK study: A multicentre, prospective cohort study","volume":"2","author":"Russell","year":"2021","journal-title":"Lancet Microbe"},{"key":"ref_40","doi-asserted-by":"crossref","unstructured":"Sleziak, J., Blazejewska, M., and Duszynska, W. (2025). Central line-associated bloodstream infections in intensive care unit during and after the COVID-19 pandemic, 5-year prospective observational study. J. Clin. Med., 14.","DOI":"10.3390\/jcm14165655"},{"key":"ref_41","doi-asserted-by":"crossref","unstructured":"Leitl, C.J., Stoll, S.E., Wetsch, W.A., Kammerer, T., Mathes, A., Bottiger, B.W., Seifert, H., and Dusse, F. (2023). Next-generation sequencing in critically ill COVID-19 patients with suspected bloodstream infections. J. Clin. Med., 12.","DOI":"10.3390\/jcm12041466"},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"253","DOI":"10.18683\/germs.2022.1327","article-title":"Incidence of bloodstream infections in patients with COVID-19: A retrospective cohort study of risk factors and outcomes","volume":"12","author":"Santos","year":"2022","journal-title":"Germs"}],"container-title":["Microorganisms"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2076-2607\/14\/9\/1941\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,2]],"date-time":"2026-09-02T09:08:40Z","timestamp":1788340120000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2076-2607\/14\/9\/1941"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,9,2]]},"references-count":42,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2026,9]]}},"alternative-id":["microorganisms14091941"],"URL":"https:\/\/doi.org\/10.3390\/microorganisms14091941","relation":{},"ISSN":["2076-2607"],"issn-type":[{"value":"2076-2607","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,2]]}}}