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Necrotizing pneumonia due to Pseudomonas aeruginosa secondary to severe COVID-19 pneumonia
Jun Hirai1,2, Nobuaki Mori1,2, Nobuhiro Asai1,2, Hiroshige Mikamo1,2
1 Department of Clinical Infectious Diseases, Aichi Medical University Hospital, Aichi, Japan
2 Department of Infection Control and Prevention, Aichi Medical University Hospital, Aichi, Japan
Address correspondence to: Dr. Jun Hirai, Department of Clinical Infectious Diseases, Aichi Medical University, 1-1 Yazakokarimata, Nagakute-shi, Aichi 480-1195, Japan.
Tel: +81-561-62-3311
Fax: +81-561-61-1842
E-mail:hiraichimed@gmail.com
Keywords: COVID-19, necrotizing pneumonia, Pseudomonas aeruginosa , mechanical ventilation, secondary infection
A 60-year-old man was admitted to our hospital with a 7-hour history of dyspnea. On admission, his vital signs were as follows: blood pressure, 90/56 mmHg; heart rate, 112 beats/min; body temperature, 40.5℃; respiratory rate, 32 breaths/min; and oxygen saturation, 88% on 15 L/min oxygen via a reservoir mask. He was diagnosed with severe COVID-19 pneumonia, confirmed by polymerase chain reaction testing, intubated and admitted to the intensive care unit the diagnosis of severe COVID-19 pneumonia. Computed tomography (CT) of the chest showed bilateral diffuse ground-glass opacities primarily in the upper lobes and consolidation in the lower lobes (Figure 1a-c), but no evidence of pulmonary embolism on contrast-enhanced CT. The patient was treated with remdesivir (200 mg loading dose on day 1, followed by 100 mg daily for up to 9 additional days), dexamethasone (6.6 mg/day), and baricitinib (4 mg/day) for 10 days, according to the current recommendations for COVID-19 management. He gradually recovered and was afebrile with a stable respiratory condition after completing 10 days of treatment. However, on hospital day 12, he developed a fever (39.8℃) and recurrent respiratory distress. Chest CT revealed new multifocal consolidations with thick-walled cavitation in both lungs (Figure 1d-f) and he was diagnosed with necrotizing pneumonia (NP). We immediately started tazobactam/piperacillin (18 g/day), but the patient died the next day. Sputum and two sets of blood cultures obtained on hospital day 12 confirmed Pseudomonas aeruginosa . However, the tip of the central venous catheter culture revealed no organism and transthoracic echocardiography showed no obvious vegetation of the heart valves.
Necrotizing pneumonia is a severe form of lung disease including necrosis of lung parenchyma with the formation of abscesses and cavitation and has a high mortality rate.1 NP occurs as a complication in 0.8% of cases of community-acquired pneumonia.2 The most common pathogens areStaphylococcus aureus and Streptococcus pneumoniae .3 In patients with COVID-19 pneumonia on invasive mechanical ventilation, the incidence of NP ranges from less than 0.5%4 to 4.5%, and Klebsiella pneumoniaeand P. aeruginosa are the most common pathogens.5 A retrospective study reported NP was diagnosed at a median of 27 days after COVID-19 symptom onset.5
This case illustrates that NP can occur as a secondary infection even if the clinical course of COVID-19 pneumonia is favorable, particularly in patients on invasive mechanical ventilation.