Acinetobacter baumannii is an opportunistic pathogen, causing serious hospital‑acquired infections, especially of the respiratory tract. A case of nosocomial pneumonia with respiratory failure was presented. An infection was found in a 58‑year‑old female admitted to a hospital for Streptococcus pneumoniae pneumonia. Despite appropriate therapy, the pneumonia progressed and massive structural changes in the lungs were observed and a multi‑drug resistant strain of Acinetobacter baumannii was cultured from sputum. After a targeted antibiotic was administered, the clinical status of the patient improved gradually, but there was no improvement in the radiological picture. However, in a chest X‑ray performed 1.5 year later, only small fibrous changes in the left lung were observed. This demonstrates both high and slow regenerative capacity of the pulmonary parenchyma.