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Freiburg scientists show in a clinical study how a newly developed bacterial PCR method optimizes and shortens the administration of antibiotics for severe pneumonia / Publication in Lancet Respiratory Medicine

Since SARS-CoV-2 at the latest, the polymerase chain reaction, or PCR for short, has been widely known as a rapid detection method for viruses. For more than ten years, this molecular biological method has been used to detect viral infections, among other things. In contrast, bacterial diagnostics is based on the cultivation of bacterial cultures. Results are only available after at least 48 hours. In a first randomized study with 208 patients, scientists at the Medical Center - University of Freiburg were able to show that a newly developed PCR test for bacterial detection in severe pneumonia contributes to faster pathogen diagnosis and better control of antibiotic therapy. The results were published on May 23, 2022 in the renowned journal Lancet Respiratory Medicine.

"Since rapid antibiotic administration is life-saving in cases of severe pneumonia, patients have so far been treated with broad-spectrum antibiotics, even if there are no bacterial findings from the laboratory," explains research leader Prof. Dr. Daiana Stolz, Medical Director of the Department of Pneumology at the Medical Center - University of Freiburg. "The use of the newly developed detection system enables the targeted administration of antibiotics - after just four hours. This not only improves antibiotic therapy for patients with pneumonia, but also slows down the development of antibiotic resistance in the medium term."

Shortening the duration of broad-spectrum antibiotics enormously

Respiratory infections are so common that they account for almost 75 percent of all antibiotic use worldwide. If pneumonia is diagnosed, physicians usually prescribe a broad-spectrum antibiotic. In the case of severe cases, patients with a weakened immune system or previous hospitalization, the lungs are flushed with a liquid using bronchoscopy, which is then examined for viruses, bacteria and fungi.

The patients included in the clinical study required such pathogen diagnostics. While bacterial cultures were created in half of the patients as before, so that the antibiotic administered could only be adjusted secondarily after around two days, the second group of patients received bacterial PCR and thus the optimal active ingredient after just four hours.

"The current study findings show that the duration of unjustified broad-spectrum antibiotic administration could be reduced by 45 percent in patients with bacterial PCR," says Stolz. "The faster switch to targeted antibiotic administration prevents over- and under-treatment and minimizes the risk of resistance developing. At the same time, beneficial bacteria are spared and side effects are reduced."

The preliminary study published in 2018, in which the research team was able to demonstrate the reliability of the bacterial PCR method for the early diagnosis of Gram-negative pathogens, served as the basis. In contrast to Gram-positive bacteria, this class of bacteria has an additional outer membrane. Due to the different cell wall structure of the two classes of bacteria, different antibiotics are effective.

"Thanks to the continuous improvement in PCR technology, we have already been able to start the next study, which will include both bacterial and viral rapid PCR. The tests will also detect gram-positive pathogens. The plan is to include over 700 patients," says the Freiburg pneumologist Stolz. "I am confident that many patients will be able to benefit from the procedure in the future."

Original title of the study: Fast multiplex bacterial PCR of bronchoalveolar lavage for antibiotic stewardship in hospitalized patients with pneumonia at risk of Gram-negative bacterial infection (Flagship II): a multicentre, randomized controlled trial
DOI:doi.org/10.1016/S2213-2600(22)00086-8
Link to the study: www.thelancet.com/journals/lanres/article/PIIS2213-2600(22)00086-8/fulltext

Contact:
Prof. Dr. Daiana Stolz
Medical Director
Department of Pneumology
Medical Center - University of Freiburg
Phone: 0761 270-37050
daiana.stolz@uniklinik-freiburg.de