Antibiotic Resistance in Respiratory Bacterial Isolates From Critical Care Patients Infected With Sars-CoV2

Abstract Purpose. Although secondary bacterial infections are uncommon in COVID-19, ventilator pneumonia is a hazard. We undertook a retrospective, observational study at an ICU in Vicenza, Italy, comparing pulmonary bacterial isolates between COVID-19 and non-COVID-19 patients.Methods. Respiratory bacteria were recovered from: (i) ICU patients admitted in Feb-May 2019, pre-pandemic; (ii) ICU patients admitted with COVID-19 during the first (Feb-May 2020) wave and (iii) non-COVID-19 ICU patients from Feb-May 2020. Results. We reviewed 120 patients, 61 in the control (2019) group and 59 (28 COVID-19 and 31 non-COVID-19) from 2020. Two hundred isolates were grown: 101 from the 2019 control patients, 42 from the 2020 COVID-19 patients and 57 from the 2020 non-COVID patients. Enterobacterales dominated throughout but Pseudomonas aeruginosa was significantly (p <0.01) more prevalent in COVID-19 than non-COVID patients and MDR P. aeruginosa (3/12; 25%) were exclusively found in COVID-19 patients. Other critical resistance types (MRSA, ESBL- and carbapenemase-producing Enterobacterales) were rare, without significant differences in prevalence between groups. ICU and hospital mortality were greater among COVID-19 than non-COVID patients. Deaths occurred in 6/9 COVID patients (66.7%) who did not receive targeted antibiotic therapy despite microbiological diagnosis.Conclusion. These data underscore the importance of secondary bacterial pathogens in ICU COVID patients and the threat of antibiotic inadequacy favouring poor outcomes in VAP. The organisms found in COVID patients were typical of VAP, though P. aeruginosa was more prominent.