Pathogen distribution and prognostic risk factors in respiratory intensive care unit (RICU) patients of a large general hospital before and after COVID-19 pandemic.

BACKGROUND

The evolving pathogen spectrum and prognosis of severe pulmonary infections in the respiratory intensive care unit (RICU) during the coronavirus disease 2019 (COVID-19) pandemic remain unclear. This study aimed to investigate shifts in the pathogen landscape of pulmonary infections among intensive care unit (ICU) patients following the regular prevention and control of COVID-19.

METHODS

A total of 132 patients with pulmonary infections admitted to the RICU of the First Affiliated Hospital of Anhui Medical University between January 2022 and March 2023 were included in the study. Patients were categorized into two cohorts: pre-strategy (n=65, Jan to Nov 2022) and post-strategy (n=67, Dec 2022 to Mar 2023), based on the implementation of regular COVID-19 prevention and control measures. Metagenomic next-generation sequencing (mNGS), and conventional tests using bronchoalveolar lavage fluid (BALF) and blood samples were used to detect pathogens. Retrospective data were obtained from the patients' medical records. The spectrum of pathogens was analyzed. Additionally, univariate and multivariate logistic regression models were employed to analyze the risk factors associated with adverse outcomes.

RESULTS

After the regular prevention and control of COVID-19 in December 2022, there was a significant shift in the pathogen landscape. The proportion of patients with severe acute respiratory coronavirus 2 (SARS-CoV-2) increased dramatically from 0% to 74.6%. This was accompanied by a significant rise in the incidence of () infections. Among the COVID-19 patients, a slight decrease in Gram-negative (G-) bacterial co-infections and a corresponding increase in Gram-positive (G+) bacterial co-infections was observed. The overall mortality rate among all enrolled patients was 30.3%, with 24.6% in the pre-strategy group and 35.8% in the post-strategy group. Additionally, there was a marked increase in the detection rates of and herpes simplex virus 1 (HSV-1) in COVID-19 patients following the strategy change. The analysis of risk factors revealed that a poor prognosis was strongly associated with co-infections of SARS-CoV-2 with [odds ratio (OR) =2.91, 95% confidence interval (CI): 1.01-8.41] or (OR =3.08, 95% CI: 0.89-10.66) species. Further, bacterial and fungal co-infections (OR =3.92, 95% CI: 1.41-10.86) were identified as significant risk factors for a poor prognosis in patients without COVID-19.

CONCLUSIONS

Our findings highlight the pathogen spectrum in RICU patients changed significantly after the shift in COVID-19 policy. Co-infections with fungi and G+ bacteria require increased clinical vigilance and early intervention to improve outcomes.