PMC9844142_01
Imaging examination. (A) Magnetic resonance imaging (MRI) of vertebra lumbalis showed a 26 mm x 73 mm subcutaneous abscess with low signal intensity on T1WI and high signal intensity on T2WI (arrows). (B) The chest radiograph showed that the patient's lungs were normal.
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T1WI and high signal intensity on T2WI, and the boundary was vague, indicating that it was a subcutaneous abscess (Figure 1A). The chest radiograph showed that the patient's lungs were normal (Figure 1B). 
Pathogenic examination. (A) Gram-positive and branching rod-shaped bacterium was observed by Gram staining under oil mirror (x1000 magnification). (B) Acid fast staining showed weak positive mycelia, which proved that it was probably Nocardia spp. (C) Wrinkled, dry and white colonies of different sizes were observed by culture on the blood plate. (D) Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) confirm it was Nocardia cyriacigeorgica.
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Gram staining and acid-fast staining were performed on the pus extracted from the abscess, and the observation under the oil microscope showed that it was branching gram-positive rod and partially acid-fast, suggesting that it was likely to belong to Nocardia spp (Figure 2A and B). The colony was dry or waxy, with wrinkles and particles on its surface (Figure 2C). The colonies were identified by Matrix-assisted laser desorption ionization-time-of-flight mass spectrometry (MALDI-TOF MS) (bioMerieux, France) with 99.9% confidence value as N. cyriacigeorgica (Figure 2D).