Abstract

Aim: To study the impact of COVID-19 admissions during 1st and 2nd surges on bacteriology of ICU respiratory isolates.

Method: Retrospective time trend analysis of bacterial respiratory isolates from a single centre, tertiary cardio-thoracic ICU (CT-ICU) from patients admitted from Jan 2018- June 2021. We compared pre-COVID-19 (January 2018- March 2020) and COVID-19 periods (April 2020- June 2021) and surge periods (surge 1: March 2020- June 2020, surge 2: January- March 2021) to similar time frames in previous years. Chi-square test used to compare proportions.

Results: 4974 respiratory isolates (Sputum-4230, BAL-563, ET secretions-181) included.

During surge 2, culture positivity and gram-negative rates tripled from baseline (20% to 75%; p<0.05).

Comparing the pre- pandemic to pandemic period, rates of Klebsiella sp, Acinetobacter sp  and Stenotrophomonas sp increased from 12% to 21.3%, 2.4% to 6.2% and 10.5% to 14.3% respectively, while Pseudomonas sp dropped from 30.7% to 23.1% (all p<0.05). MDR Pseudomonas increased significantly from 38.9% to 47.9% (p<0.05), with a non-significant increase in MRSA (5.2% to 9.3%; p=0.34) and MDR enterobacterales (22.6% to 23%; p=0.48).

Conclusion: This is the first report from a UK CTICU showing a marked epidemiological shift in the bacteriology of respiratory isolates in terms of organism profile, increase in culture positivity and MDR Pseudomonas rates during the pandemic.  Analyzing trends on longevity of the findings will help guide changes to infection control and antibiotic policies. This emphasizes the importance of unit specific ecology in choosing appropriate timely antimicrobial therapy and therefore improving patient outcome.