Among newly hospitalized adults with COVID-19 who had bacterial cultures, 6.0% were found to have a potentially serious bacterial infection, according to study findings published in Influenza and Other Respiratory Viruses.
Researchers used data from the Coronavirus Disease 2019-Associated Hospitalization Surveillance Network (COVID-NET) to assess the proportion of viral and bacterial infections in hospitalized adults with laboratory-confirmed COVID-19. COVID-NET includes data from more than 250 acute care hospitals in 14 US states.
The study analysis included adults hospitalized with COVID-19 from March 2020 to April 2022 who had bacterial culture testing within 7 days of admission (including 7 days before or 7 days after). Pathogens from sterile or respiratory sites only were included. The investigators also assessed results of polymerase chain reaction testing done on patients within 7 days of admission (before or after) for respiratory syncytial virus (RSV), rhinovirus/enterovirus (RV/EV), influenza (subtypes A, B, or unspecified), adenovirus, human metapneumovirus (HMPV), parainfluenza (serotypes 1-4), and seasonal human coronaviruses (229E, HKU1, NL63, OC43).
Of the 36,490 adults who were hospitalized from March 2020 to April 2022, 18,376 (53.3%) had bacterial cultures from sputum, deep respiratory, blood, or other sterile sites. A bacterial pathogen was identified in 6.0% (1140) of patients in this group. Among individuals with bacterial infections, in-hospital death occurred in 31.7% compared with 13.2% of those without bacterial infections in bivariate analysis (P <.0001).
Patients with COVID-19 who had bacterial infections within 7 days of admission had a 2.28 (95% CI, 1.87-2.79) times increased risk of death vs those with negative bacterial cultures, after adjustment for demographic factors, underlying medical conditions, and time period. Participants with an identified clinically relevant pathogen had an increased need for intensive care (relative risk [RR] 2.11; 95% CI, 1.95-2.23) and mechanical ventilation (RR 3.04; 95% CI, 2.74-3.37).
Of 1140 patients with a bacterial infection, 35.4% had a positive sputum culture, 44.0% had a positive blood culture, 23.4% had a positive deep respiratory culture, and 3.2% had a positive culture from another sterile site. Among those with positive sputum bacterial cultures, 46.7% were Staphylococcus aureus (S aureus), which also accounted for 43.9% of organisms in deep respiratory cultures and 35.1% in blood cultures.
Among 329 hospitalized adults with COVID-19 who died, S aureus (46.3%) and Escherichia coli (17.0%) were the most frequently occurring pathogens in blood, S aureus (51.7%) and Pseudomonas aeruginosa (12.4%) the most common in sputum, and S aureus (40.2%) and P aeruginosa (17.2%) the most common in deep respiratory specimens.
Of the patients with COVID-19 whose charts were available for a complete review, 9316 (25.5%) had undergone testing for other respiratory viruses. Among 2766 participants who were tested for parainfluenza, adenovirus, HMPV, RV/EV, RSV, common human coronaviruses, and influenza, another virus was detected in 30 individuals (0.9%), with RV/EV (0.6%) the most frequently detected virus.
Among several limitations, the findings may not be generalizable to all US adults hospitalized with COVID-19, and testing practices vary. Also, the percentage of adults with COVID-19 receiving bacterial testing changed over time. Furthermore, detection of viral pathogens by PCR or bacterial pathogens by culture may not indicate active infection or disease, and COVID-NET only includes bacterial pathogens within 7 days of admission.
“As SARS-CoV-2 continues to circulate and individuals continue to be hospitalized for COVID-19, understanding risk factors for bacterial infections and associated outcomes can help guide clinicians in providing optimal care,” the researchers commented.
Disclosure: One of the study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Shah MM, Patel K, Milucky J, et al. Bacterial and viral infections among adults hospitalized with COVID-19, COVID-NET, 14 states, March 2020-April 2022. Influenza Other Respir Viruses. 2023;17(3):e13107. doi:10.1111/irv.13107