PMC10464891_01
CT plain scan of the patient's abdomen. The red arrow indicates the low-density region, considering possible abscess (left, left psoas major; right, spleen).
IDR-16-5613-g0001.jpg
PMC10464891_01_IDR-16-5613-g0001.jpg
f0001
On 8th July (Day 2), the patient underwent a computed tomography (CT) plain scan of the upper abdomen, which revealed the enlarged spleen with low-density from the splenic and left psoas major, showing a possible abscess with inflammatory exudate (Figure 1).
Serum antibody detection of the patient. (A) B. pseudomallei IgG showed strongly positive by GICA; (B) Hcp1 IgG and IgM ELISA reactivity (OD) and titre of serum collected after admission.
IDR-16-5613-g0002.jpg
PMC10464891_01_IDR-16-5613-g0002.jpg
f0002
Cefoperazone-tazobactam was promptly administered to the patient based on the detection of serum anti- Hcp1 antibodies to B. pseudomallei, which were determined to be strongly positive for IgG strip (Figure 2). The sera were collected at five different time points during the days of hospitalization (Figure 2B). For GICA, the diluted serum was added to the strip and read after 15 minutes, only IgG was positive (Figure 2A).
Microbiological examination of the pus sample. (A) The light circle indicates Gram-negative rods on the pus smear with Gram stain; (B) Colonies on blood plate; (C) Colonies on chocolate plate; (D) Colonies on China blue plate; (E) Phylogenetic analysis of the 16S rRNA gene amplified from the clinical isolate BP-HS compared with that of publicly available B. pseudomallei and Burkholderia spp.
IDR-16-5613-g0003.jpg
PMC10464891_01_IDR-16-5613-g0003.jpg
f0003
The diagnosis of splenic and psoas major abscess due to melioidosis was finally confirmed on 20th July (Day 14) by pus culture as shown in Figure 3 (blood cultures taken prior to antibiotics were negative), and anti-infective therapy was continued. Direct smear and Gram stain showed tiny numbers of Gram-negative rods with WBC (Figure 3A). After 24 hours of culture, small, smooth, creamy white, neatly edged, milky and slightly sticky colonies were seen on the blood plates. 72 hours later, pale white-yellow, subcircular, dry, wrinkled, and opaque "daisy-like" colonies were observed (Figure 3B-D). DNA extracted from the isolated strain using a Bacterial DNA Kit (TIANGEN, Beijing), and amplified using a 16S rDNA Bacterial Identification PCR Kit (Sangon, Shanghai), was sent to BGI company for sequencing. Direct sequencing and phylogenetic analysis of the PCR amplification products showed that the isolate (named BP-HS) was unequivocally clustered with B. pseudomallei (Figure 3E).