Bacterial and fungal co-infections among COVID-19 patients in intensive care unit

Abstract

This study aimed to investigate the frequency and characteristics of respiratory co-infections in COVID-19 patients in the intensive care unit (ICU). In this retrospective observational study, pathogens responsible for potential co-infections were detected by the bacterial culture, real-time polymerase chain reaction (RT-PCR), or serological fungal antigen tests. Demographic and clinical characteristics, as well as microbial results, were analyzed. Bacterial culture identified 56 (58.3%) positive samples for respiratory pathogens, with the most common bacteria being Burkholderia cepacia (18, 18.8%). RT-PCR detected 38 (76.0%) and 58 (87.9%) positive results in the severe and critical groups, respectively. Most common pathogens detected were Stenotrophomonas maltophilia (28.0%) and Pseudomonas aeruginosa (28.0%) in the severe group and S. maltophilia (45.5%) in the critical group. P. aeruginosa was detected more during the early stage after ICU admission. Acinetobacter baumannii and Staphylococcus aureus were more frequently identified during late ICU admission. Fungal serum antigens were more frequently positive in the critical group than in the severe group, and the positive rate of fungal serum antigens frequency increased with prolonged ICU stay. A high frequency of respiratory co-infections presented in ICU COVID-19 patients. Careful examinations and necessary tests should be performed to exclude these co-infections.

Keywords: COVID-19; Co-infection; Critically ill patient; ICU; Respiratory pathogen.

Fig. 1

Respiratory pathogens from each specimen in critically ill COVID-19 patients. Respiratory pathogens were detected by microbial culture and a multiple RT-PCR assay. Detected bacteria in individual specimens of each patient in the severe and critical groups are shown in A and B, respectively. The results from specimens were classified as the date of patients admitted to the ICU. Patients S1 – 7 had severe illness and patients C1 – 13 had critical illness. Note. a, the date of receiving mechanical ventilation; b, the date of supporting ECMO; ↑, the date of being transferred to the general ward.