P195 Secondary infection rates and antibiotic prescribing in a COVID-19 HDU population

• Published in: Thorax Vol. 76; no. Suppl 1; p. A195
• Main Authors: Zhang, SH, Bickler, G, Porter, B, Hallifax, R, Rahman, N, Flight, W
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group LTD 01.02.2021
• Subjects: Antibiotics; Coronaviruses; COVID-19; Infections; Intubation; Mortality; Severe acute respiratory syndrome coronavirus 2; Ventilation
• ISSN: 0040-6376; 1468-3296
• DOI: 10.1136/thorax-2020-BTSabstracts.340

IntroductionSecondary infection in COVID-19 has been associated with adverse outcomes and high mortality. The prevalence of secondary infection in COVID-19 and optimal antimicrobial strategies remain unclear.MethodsRetrospective case-note review of patients with COVID-19 admitted to our institution’s high dependency unit (HDU) from March to June 2020. Patients were PCR-positive for SARS-CoV-2 or had classical CT appearances and a compatible clinical presentation for COVID-19. Microbiological tests, antimicrobial prescriptions and clinical outcomes were recorded.Results84 patients were identified. Median age was 68.5 years and 29/84 (34.5%) were female. Respiratory support included HFNO (n=39), CPAP (n=56), non-invasive ventilation (n=3) and invasive ventilation (n=14). Overall mortality was 36/84 (42.9%).6/84 patients (7.1%) had evidence of secondary infection (>105 CFUs on bronchoalveolar lavage (BAL); positive sputum culture or positive blood culture excluding skin contaminants).28/84 (33.3%) had a respiratory sample sent: BAL n=10; sputum culture n=2; Legionella antigen n=15; throat swab multiplex PCR n=3; Biofire respiratory viral panel n=7. BAL was positive in 3/10 cases (Enterococcus faecium; Serratia marcescens and Escherichia coli; Pseudomonas aeruginosa). One sputum culture was positive for M. abscessus.71/84 (84.5%) had blood cultures. 8 (11.2%) were positive, of which 6 were considered skin contaminants and not deemed true secondary infection (coagulase negative Staphylococci n=5; Lysinibacillus sp. n=1; Proteus mirabilis n=1; Staphylococcus epidermidis and Serratia marcescens n=1).All 84 patients received antimicrobials. 32 (38.1%) received a macrolide, predominantly azithromycin. Macrolide usage was not associated with mortality or admission length, but was associated with increased intubation rate (28.1% vs 9.6%, p=0.027)Initial antibiotic treatment was monotherapy in 45 (53.6%) cases and dual therapy in 39 (46.4%). Initial treatment with two antibiotics versus monotherapy was not associated with mortality but was associated with increased intubation rate (25.6% vs 8.9%, p=0.040) and increased mean admission length (16.5 vs 11.6 days, p=.036).DiscussionRobust evidence of secondary infection in patients with COVID-19 was uncommon in our cohort. Increased intubation rates in patients prescribed a macrolide and those initially prescribed dual antibiotic therapy is likely to reflect more severe disease. There is considerable potential for enhanced antimicrobial stewardship in further waves of COVID-19.