Hospital-Acquired Bacterial Coinfections Common in Severe COVID-19

Bacterial coinfections were found to be common among patients hospitalized with COVID-19 infection, with most acquired during hospital admission. These study results were published in Journal of Hospital Infection

In a retrospective study, researchers reviewed electronic health records of patients with laboratory-confirmed COVID-19 infection who were hospitalized at 3 hospitals in Serbia from January 2021 to February 2022. The researchers assessed the prevalence, etiologies, and antibiotic resistance patterns of bacterial infections occurring after the onset of COVID-19 infection. The primary outcome was in-hospital mortality; secondary outcomes included invasive mechanical ventilation. Isolated bacteria were classified using VITEK2, analytical profile index procedure, and MALDI-TOF. The antimicrobial profile of the bacteria was determined through the disk diffusion method, gradient test, VITEK2 system, or broth microdilution test. Chi-squared and Fisher tests were used for possible associations of normal variables.

Among 6478 study patients, 68.7% were older than 65 (mean age, 68.6) years, and 54.7% were men. A total of 834 (12.9%) patients had bloodstream infections (BSIs) and/or bacterial coinfections, 57.6% of whom had monomicrobial infections.

Of patients with BSIs and respiratory infections, the most commonly isolated pathogens among patients with were Klebsiella pneumoniae (47%)and Acenitobacter baumannii (75.8%), respectively. Hospital-acquired infections accounted for 11.5% of bacterial infections overall, with pneumonia (n=240) and BSIs (n=268) being the most common. Gram-negative bacterial infections were more commonly observed among the patient population than gram-positive infections (69.3% vs 30.7%, respectively).

Multidrug-, extensively drug-, and pandrug-resistant bacterial pathogens accounted for 24.2%, 37.9%, and 12.8% of all infections, respectively. Of note, pandrug-resistant bacterial pathogens were isolated from only patients with hospital-acquired infections.

Ventilator-associated pneumonia occurred among 95% of intubated patients with bacterial coinfections (n=350). Of all patients with COVID-19 and bacterial coinfection, 675 (80.93%) had severe COVID-19 infection.

The rate of in-hospital mortality rate was 51.6% overall and 55.3% for patients older than 60 years. Mortality was significantly more likely among patients older than 60 years who were infected with at least 3 pathogens (P <0.05). Overall, 91.7% of patients who required invasive mechanical ventilation died.

Limitations of this study include its retrospective design and the lack of data on COVID-19 vaccination status and use of antibiotics and corticosteroids.

According to the researchers “Our results add to the growing evidence that existed pre-COVID-19 that infection prevention and control (IPC) should be focused on MDR bacteria and C. difficile, as well as on patients undergoing invasive mechanical ventilation.”