Low rate of bacterial co-infection in patients with COVID-19
Authors: Hugh Adler, Robert Ball, Michael Fisher, Kalani Mortimer, Madhur S Vardhan
Journal: The Lancet Microbe (2020)

We agree with Michael J Cox and colleagues1Cox MJ Loman N Bogaert D O'Grady J Co-infections: potentially lethal and unexplored in COVID-19.Lancet Microbe. 2020; 1: e11Summary Full Text Full Text PDF PubMed Google Scholar that clinical management of COVID-19 would be enhanced by further characterisation of bacterial co-infections. A few case reports have described examples of such co-infections.2Duployez C Le Guern R Tinez C et al.Panton-valentine leukocidin-secreting Staphylococcus aureus pneumonia complicating COVID-19.Emerg Infect Dis. 2020; (published online April 16.)DOI:10.3201/eid2608.201413Crossref PubMed Scopus (37) Google Scholar, 3Edrara EM Lopez EB Villarama JB et al.First COVID-19 infections in the Philippines: a case report.Trop Med Health. 2020; 48: 21Crossref PubMed Scopus (61) Google Scholar, 4Khaddour K Sikora A Tahir N Nepomuceno D Huang T Case report: the importance of novel coronavirus disease (COVID-19) and coinfection with other respiratory pathogens in the current pandemic.Am J Trop Med Hyg. 2020; (published online April 17.)DOI:10.4269/ajtmh.20-0266Crossref PubMed Scopus (22) Google Scholar However, national5NHSClinical management of persons admitted to hospital with suspected COVID-19 infection.https://www.england.nhs.uk/coronavirus/wp-content/uploads/sites/52/2020/03/clinical-management-of-persons-admitted-to-hospita-v1-19-march-2020.pdfDate: 2020Date accessed: April 14, 2020Google Scholar and international6WHOClinical management of severe acute respiratory infection when COVID-19 is suspected.https://www.who.int/publications-detail/clinical-management-of-severe-acute-respiratory-infection-when-novel-coronavirus-(ncov)-infection-is-suspectedDate: 2020Date accessed: April 14, 2020Google Scholar guidelines recommend empirical antibiotics for all patients who are severely ill with suspected COVID-19, and that cessation of therapy is left to the clinicians' discretion. Pending the widespread availability of metagenomic sequencing as envisaged by Cox and colleagues,1Cox MJ Loman N Bogaert D O'Grady J Co-infections: potentially lethal and unexplored in COVID-19.Lancet Microbe. 2020; 1: e11Summary Full Text Full Text PDF PubMed Google Scholar we argue that traditional diagnostics still have a role. We reviewed all microbiology results for patients admitted to Whiston hospital (Prescot, UK) with PCR-confirmed COVID-19 between March 6, 2020, and April 7, 2020. Hospital policy for patients admitted with community-acquired pneumonia, including suspected COVID-19 cases, recommends blood cultures and pneumococcal and Legionella urinary antigen tests based on clinical severity, in line with national guidelines.7Lim WS Baudouin SV George RC et al.BTS guidelines for the management of community acquired pneumonia in adults: update 2009.Thorax. 2009; 64: iii1-iii55Crossref PubMed Scopus (154) Google Scholar We collected the data to inform and update the hospital's antimicrobial policy, with approval from the Trust Quality Improvement and Clinical Audit department. We recorded results for 7 days from the positive COVID-19 test because positive samples collected after this time period might represent hospital-acquired infections. Samples unequivocally consistent with contamination were considered negative. We identified 195 patients (for demographics and microbiology see appendix p 1). Five (3% of 195, or 4% of 137 patients specifically tested), had pneumococcal co-infection and all survived to hospital discharge. One of 31 patients tested was positive for the Legionella antigen without lower respiratory tract samples to confirm legionellosis. Bacteria grew from four of 26 sputum samples (appendix p 1). All bacteria were Gram-negative bacilli more typically associated with oropharyngeal colonisation than community-acquired pneumonia. Our findings suggest that bacterial co-infection is uncommon in patients with COVID-19 who are newly admitted to hospital. The co-prevalence of pneumococcus and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was low, and Staphylococcus aureus was not detected. By contrast, in influenza infection the prevalence of bacterial co-infection in hospitalised patients can exceed 30%.8Chertow DS Memoli MJ Bacterial coinfection in influenza: a grand rounds review.JAMA. 2013; 309: 275-282Crossref PubMed Scopus (298) Google Scholar, 9Bisno AL Griffin JP Van Epps KA Niell HB Rytel MW Pneumonia and Hong Kong influenza: a prospective study of the 1968–69 epidemic.Am J Med Sci. 1971; 261: 251-263Crossref PubMed Scopus (79) Google Scholar These results suggest that routine antibiotics might not be indicated in patients with COVID-19. If superimposed bacterial community-acquired pneumonia is suspected, coverage for typical pathogens such as pneumococcus might suffice, unless there is specific clinical concern for infection with atypical agents. The main strength of our report is the correlation of microbiology results with all consecutive COVID-19 admissions. The main limitation is the variability of microbiological sampling. Our results might not be generalisable to other geographical settings. Future studies should implement standardised microbiological sampling for all COVID-19 admissions and prospectively correlate the prevalence of co-infection with mortality rates. Such studies could also correlate clinical and laboratory findings with the presence of co-infection to support rational prescribing of antibiotics. We declare no competing interests. Download .pdf (.16 MB) Help with pdf files Supplementary appendix Co-infections: potentially lethal and unexplored in COVID-19Respiratory viral infections predispose patients to co-infections and these lead to increased disease severity and mortality. Most fatalities in the 1918 influenza outbreak were due to subsequent bacterial infection, particularly with Streptococcus pneumoniae.1 Poor outcomes in the 2009 H1N1 influenza pandemic were also associated with bacterial co-infections, although few studies captured these data.2 Full-Text PDF Open Access