COVID-19: Utility of Antibiotic Therapy for Nosocomial Coinfection Unclear

Virus cells. Coronavirus Covid-19 concept image.
Patients with COVID-19 who are admitted to the ICU may experience higher rates of coinfections requiring antibiotic therapy compared with non-ICU patients.

Patients diagnosed with coronavirus disease 2019 (COVID-19) who are not admitted to the intensive care unit (ICU) may not require antibiotic therapy due to the low frequency of community-acquired coinfection, according to the results of a single-center study published in Clinical Infectious Diseases.

Current literature estimates that coinfection in COVID-19 could range from 0% to 40% of patients. As such, concerns have been raised on whether coinfection could be a significant complication in COVID-19. However, only a few studies were designed to assess co-infection and differentiate between community- and hospital-acquired coinfection, coinfection definitions are variable, and microbiologic data are inconsistently reported. As a result of these challenges, the current guidelines on antibiotic use in COVID-19 patients are not strong. This retrospective, observational study described the rates of community-acquired coinfection in patients with COVID-19.

In total, 321 patients with COVID-19 (³18 years of age) were admitted to the University of Chicago Medical Center in Chicago, Illinois during the evaluation period (March 1, 2020-April 11, 2020). The date of hospital admission, ICU admission, mortality, antibiotic administration, and microbiologic test results were examined. If positive test results were collected after the fifth day of hospital admission, patients were excluded to make sure only community-acquired coinfection was captured.

COVID-19 was diagnosed by the presence of SARS-CoV-2 RNA in respiratory swabs. Coinfection was defined by clinical signs and/or symptoms of infection and detection of a pathogen by diagnostic tests (respiratory bacterial cultures, nasopharyngeal polymerase chain reaction, urine Streptococcus pneumoniae antigen, and urine Legionella pneumophilia antigen). Proportional differences of co-infection between ICU patients and non-survivors were calculated.

Study results demonstrated that community-acquired coinfection in COVID-19 was infrequent and was often viral in nature. Patients had a mean age of 60 years, and 48% were men. In total, 5% of patients were admitted to the ICU and 7% died. At least 1 test for coinfection was performed in 98% of patients. Coinfection was identified in 3.7% of patients; 1.2% of these patients had bacterial infections.

Of the 66 patients that received respiratory cultures, 3% had coinfection. Only 2 patients demonstrated co-infection with more than 1 pathogen. Coinfection was more frequent in patients admitted to the ICU (41% patients; P <.005), but not for non-survivors (9% patients; P =.17). Although there was an overall low frequency of coinfection, antibiotic use was high (69%).

Study limitations include the strict definition of coinfection applied by researchers, requiring coinfections to be microbiologically proven. This study was limited to community-acquired coinfection and not the evaluation of nosocomial, hospital-acquired coinfection. Additionally, since this study was a single center experience, results may not be generalizable.

“Based on these findings, we suggest patients admitted with COVID-19 may not require antibiotic therapy. However, patients admitted to the ICU may,” the researchers concluded. “Due to the limitations of this project, we cannot recommend for or against the use of antibiotics in patients with COVID-19.”

Further prospective controlled studies are required to determine the optimal role of antibiotic therapy in COVID-19.


Lehmann CJ, Pho MT, Pitrak D, Ridway JP, Pettit NN. Community-acquired co-infection in COVID-19: a retrospective observational experience [published online July 1, 2020]. Clin Infect Dis. doi:10.1093/cid/ciaa902/5865452