en Infectious diseases and public health Infectious diseases and public health Original article Original article <div style="text-align: justify;"><b><span style="font-size:10.0pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times="">Introduction:</span></span></span></b><span style="font-size:10.0pt"><span style="line-height:107%"><span new="" roman="" style="font-family:" times=""> Since the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), bacterial co-infections have become an important concern in the clinical management of coronavirus disease 2019 (COVID-19), especially in patients with severe illness, as they contribute to increased morbidity and mortality. This study aimed to investigate the epidemiological and clinical characteristics of bacterial co-infections in hospitalized patients with severe COVID-19 in Yazd Province, Iran. <b>Methods: </b>In this retrospective descriptive-analytical study, 110 adult patients with reverse transcription polymerase chain reaction-confirmed COVID-19 (RT-PCR) and positive blood cultures, hospitalized at Shahid Sadoughi Hospital between February 2020 and February 2023, were evaluated. Data were extracted from electronic health records and patient files, including demographic information, comorbidities, clinical symptoms, complications, oxygen therapy details, admission oxygen saturation, duration of hospitalization, isolated bacterial or fungal pathogens, treatments, laboratory results, and clinical outcomes. Blood culture findings were independently reviewed by two investigators, and any discrepancies were resolved through consensus or by a third reviewer to minimize bias. Statistical analysis was performed using IBM SPSS Statistics version 22.0. The normality of continuous variables was assessed using the Shapiro-Wilk test, and data were presented as mean &plusmn; standard deviation (SD) or median (interquartile range [IQR]), as appropriate. Group comparisons were conducted using t-test or Mann-Whitney U test for continuous variables, and chi-square (&chi;&sup2;) or Fisher&#39;s exact tests for categorical variables. A <i>P</i>-value < 0.05 was considered statistically significant. <b>Results: </b>Patients had a mean age of 64.94 &plusmn; 18.86 years, of whom 52.7% were male. Fever and shortness of breath were the most common symptoms, and hypertension was the most prevalent comorbidity. <i>Pseudomonas aeruginosa</i> (37.3%) and <i>Klebsiella pneumoniae</i> (29.1%) were the most frequently isolated pathogens, with Gram-negative bacteria accounting for 74.5% of infections. The mortality rate among patients with positive blood cultures was 28.2%. <b>Conclusion: </b>Bacterial co-infections are more common in severe COVID-19 cases admitted to the intensive care unit (ICU) and are associated with prolonged hospital stays. Appropriate antibiotic stewardship and strict infection control measures are essential to prevent secondary infections and limit the spread of drug-resistant bacteria in healthcare settings.</span></span></span><br> &nbsp;</div> COVID-19, Bacterial co-infections, SARS-CoV-2, Secondary infections 0 0 http://jommid.pasteur.ac.ir/browse.php?a_code=A-10-645-1&slc_lang=en&sid=1 Salameh Soleymani dr.s.soleymani93@gmail.com 0009-0000-0159-4398 No Department of Internal Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Mohammad Samet samet_mo@yahoo.com 0000-0002-4124-1009 No Department of Internal Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Nasim Namiranian namiranian.nasim@gmail.com 0000-0002-5133-6204 No Diabetes Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Fatemeh al-Sadat Aghaei Meybodi afr66689@gmail.com 0000-0002-5132-2494 Yes Department of Internal Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.