Bacterial Coinfections in Coronavirus Disease 2019

Abstract

Bacterial coinfections increase the severity of respiratory viral infections and were frequent causes of mortality in influenza pandemics but have not been well characterized in patients with coronavirus disease 2019 (COVID-19). The aim of this review was to identify the frequency and microbial etiologies of bacterial coinfections that are present upon admission to the hospital and that occur during hospitalization for COVID-19. We found that bacterial coinfections were present in <4% of patients upon admission and the yield of routine diagnostic tests for pneumonia was low. When bacterial coinfections did occur, Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae were the most common pathogens and atypical bacteria were rare. Although uncommon upon admission, bacterial infections frequently occurred in patients with prolonged hospitalization, and Pseudomonas aeruginosa, Klebsiella spp., and S. aureus were common pathogens. Antibacterial therapy and diagnostic testing for bacterial infections are unnecessary upon admission in most patients hospitalized with COVID-19, but clinicians should be vigilant for nosocomial bacterial infections.

Keywords: bacterial coinfection; coronavirus disease 2019 (COVID-19); hospital-acquired infections; multidrug resistance (MDR); severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Figure 1

Algorithm to Guide Diagnostic Evaluations and Antibiotic Decision Making in Patients who are Admitted to the Hospital with COVID-19 Pneumonia. This flow diagram provides criteria for clinicians to help identify patients for whom a diagnostic work-up should be pursued and for whom empirical antibiotic therapy is warranted. It also provides guidance for the selection of antibiotics. *Consider anti-pseudomonal β-lactam agents in patients with prior Pseudomonas aeruginosa, bronchiectasis, or recent use of parenteral antibiotics. MRSA, methicillin-resistant Staphylococcus aureus.

Figure 2

Etiologies of Community-onset and Hospital-acquired Bacterial Coinfections in Patients Hospitalized with COVID-19. Community-onset bacterial infections are those that occurred within 2 days of hospital admission in 10 studies [15,16,19,20,23,25., 26., 27., 28., 29.], and hospital-acquired bacterial infections are those that occurred after the second day of hospitalization in six studies [16,31,48., 49., 50.,52]. Other bacterial etiologies of community-onset bloodstream or respiratory infections included Escherichia coli (n =5), Proteus spp. (n = 4), Legionella pneumophila (n = 4), and Citrobacter spp. (n = 2). Other hospital-onset bloodstream infections included E. coli (n = 14), Acinetobacter spp. (n = 8), Enterobacter spp. (n = 7), Serratia marcescens (n = 3), and Stenotrophomonas maltophilia (n = 3). Other respiratory tract infections included S. maltophilia (n = 9), S. marcescens (n = 8), Acinetobacter spp. (n = 7), Citrobacter spp. (n = 6), and Proteus spp. (n = 5). CoNS, coagulase-negative staphylococci; H. influenzae, Haemophilus influenzae; P. aeruginosa, Pseudomonas aeruginosa; S. aureus, Staphylococcus aureus; S. pneumoniae, Streptococcus pneumoniae.