November 28, 2021

Research reveals potential overuse of antibiotics in patients with severe SARS-CoV-2 pneumonia

According to new research published online in the American Journal of Respiratory and Critical Care Medicine by the American Thoracic Society. Superinfection occurs when another infection, often different, is superimposed on the initial infection; in this case, bacterial pneumonia occurring during severe viral pneumonia.

In “Bacterial Superinfection Pneumonia in Patients Mechanically Ventilated for SARS-CoV-2 Pneumonia”, Richard G. Wunderink, MD, professor of medicine, Division of Pulmonary and Critical Care, Northwestern University Feinberg School of Medicine, and the coauthors report a study which shows that the usual clinical criteria used to diagnose bacterial pneumonia could not distinguish between those with bacterial superinfection and those with severe infection with SARS-CoV-2 only.

According to the authors, the current guidelines that recommend that patients with SARS-CoV-2 pneumonia receive empiric antibiotics (antibiotics given on the basis of the presumption of infection, rather than on the basis of the actual detection of a bacteria ) initially on admission to hospital for suspected bacterial superinfection are based on weak evidence. The rates of superinfection pneumonia in other published clinical trials in patients with SARS-CoV-2 pneumonia are surprisingly low.

More precise assessment other than a simple review of clinical parameters is needed to enable clinicians to avoid using antibiotics in the majority of these patients, but to use antibiotics appropriately in the 20 to 25 percent who do. have a bacterial infection. “

Dr Richard G. Wunderink MD, Professor, Division of Pulmonary and Critical Care, Feinberg School of Medicine, Northwestern University

The team conducted a single-center observational study at Northwestern University to determine the prevalence and cause of bacterial superinfection at the time of initial intubation and the incidence and cause of ventilator-associated bacterial pneumonia (VAP) in 179 patients with severe SARS-CoV. 2 pneumonia requiring mechanical ventilation.

They analyzed 386 bronchoscopic bronchoalveolar lavage fluid (BAL; a procedure for taking samples deep in the lungs) from patients using quantitative bacterial cultures; that help clinicians determine the number of bacteria present; and a multiplex polymerase chain reaction (PCR) panel. The actual use of antibiotics was compared to the treatment recommended by the guidelines. Bacterial superinfection within 48 hours of intubation was detected in 21% of patients; 72 patients (44.4%) developed at least one episode of VAP; 15 (20.8 percent) of the initial VAPs were caused by difficult-to-treat bacteria.

The authors found that in patients with SARS-CoV-2 pneumonia requiring mechanical ventilation, bacterial superinfection at the time of intubation occurred in less than 25% of patients. Empirical management of antibiotics based on guidelines at the time of intubation has reportedly resulted in overuse of antibiotics. Dr Wunderink and colleagues believe their findings have multiple implications for antibiotic guidelines: “Rapid diagnostic tests are important in helping to identify suspected pneumonia in intubated patients. This may have major clinical implications as the current approach of using defined risk factors Resistant staphylococcus aureus (MRSA) or pseudomonas bacteria as the cause of pneumonia still greatly overestimate the true incidence of these pathogens. This is not only true for SARS-CoV-2, but also potentially for severe influenza. “

“Accurate diagnosis of suspected pneumonia allows clinicians to avoid or safely use narrow spectrum antibiotics for many patients,” added Dr Wunderink. “While several interventions impact mortality in these critically ill patients, the low mortality in our study with more limited antibiotic treatment suggests that our approach was safe. “

This study was supported by the National Institutes of Health.


American Thoracic Society

Journal reference:

Pickens, CO, et al. (2021) Bacterial superinfection pneumonia in mechanically ventilated patients for COVID-19 pneumonia. American Journal of Respiratory and Critical Care Medicine.

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