Burkholderia cepacia Induced Occipital Subcutaneous Abscess and Fracture in a Brain-Dead Woman

Introduction

Burkholderia cepacia (B. cepacia), a Gram-negative aerobic bacillus, is a well-known opportunistic pathogen of immune-compromised patients including cystic fibrosis, chronic granulomatous disease, and lung transplantation patients.¹ Several cases report that B. cepacia could induce extrapulmonary-tissue abscesses, such as brain, bilateral psoas, chest intra-abdominal, and deep neck.^2–8 However, soft tissue infections with fractures caused by B. cepacia are extremely rare with no instances reported. We report a middle-aged female with a medical history of 3-year brain dead who developed a subcutaneous abscess with a bone fracture in her right occipital region.

Case Report

A 40-year-old female was diagnosed with viral encephalitis-induced secondary brain death on September 11, 2019, based on the American Academy of Neurology (AAN) criteria for the determination of brain death in adults.² Her clinical manifestations presented as comatose, lack of brainstem reflexes, and cannot breathe spontaneously. The head CT showed diffuse edema of brain tissue and gray matter with white matter structure blurred (Figure 1A). The electroencephalogram (EEG) indicated resting-state brain electrical activity. Her family finally decided to transfer to the Hang Zhou Integrative Medicine Hospital. She received mechanical ventilation and rehabilitation exercise during hospitalization lasting for almost 3 years. The patient had a high fever on September 12, 2022. Physical examination revealed intense swelling of her right occipital region and the abscess was approximately four centimeters in diameter. The brain computed tomography (CT) imaging showed the right temporoparietal cerebral hemorrhage and occipital defect with a subcutaneous abscess in Figure 1B, and laboratory workup showed white blood cell, 9.0×109/L; neutrophils, 87.8%; lymphocytes, 9.1%; red blood cell, 2.84×1012/L; hemoglobin, 86 g/L; platelet, 183×109/L; C-reactive protein, 100.2 mg/L; procalcitonin, <0.25 ug/L. The sampling of abscess fluid was conducted, and bloody pus was obtained (Figure 2). The pus’s direct smear examination and culture showed B. cepacia. The colony was susceptible to cefoperazone-sulbactam, meropenem, ceftazidime, minocycline, and TMP-SMX (Table 1). To confirm the result, we further conducted metagenomic next-generation sequencing (NGS) of the abscess aspiration and revealed B. cepacia (Table 2). We analyzed its virulence genes and the major virulence factors focusing on the function of motility, such as fliM, flhA, motA, fliA, flgG, and flgI. We further found that the drug-resistant genes of this strain were mphL, satA_Ba, BcII, and bla1 via the second-generation sequencing of the whole genome.³

Table 1 Burkholderia cepacia Susceptibility Results by the MIC Test

Table 2 Pathogenic Microorganisms Identified in a Subcutaneous Abscess Sample

Figure 1 Brain CT images of the patient. (A) Brain CT imaging on October 15, 2019. The head CT imaging was showed diffuse edema of brain tissue, gray matter and white matter structure blurred. (B) Brain CT on September 14, 2022. The brain CT imaging was showed the right temporo-parietal cerebral hemorrhage and occipital defect with subcutaneous abscess.

Figure 2 The sampling of bloody pus.

The cerebrospinal fluid examination (CSF) was performed to rule out intracranial infection, and no positive results were seen in the CSF, including CSF routine, culture, Cryptococcus neoformans, Mycobacterium tuberculosis and NGS. She was then treated with Cefoperazone-sulbactam 2.0g q8h for 5 days depending on the result of the antimicrobial susceptibility testing for B. cepacia. By this series of treatments, she had no fever, and the inflammation presented white blood cells, 5.5×109/L; neutrophils, 79.6%; lymphocytes, 17.4%; red blood cells, 3.0×1012/L; hemoglobin, 89 g/L; platelet, 135×109/L; C-reactive protein, 40 mg/L; procalcitonin, <0.25 ug/L. The inflammatory markers were significantly lower than before with no apparent swollen sign of the right occipital area in several days. Worth mentioning is that the patient neither reviewed for the CT nor got enough treatment courses to objectively evaluate the therapeutic effect of the soft tissue abscess with a bone fracture because family members decided to abandon treatments.

Discussion

Extrapulmonary infection caused by B. cepacia is a rare, life-threatening disease usually found in immunocompromised patients.^1,3 B. cepacia-induced infections are difficult to treat because the pathogen is resistant to multiple antibiotics inherently.³

Several cases report that B. cepacia could cause abscesses in the brain, bilateral primary psoas, chest intra-abdominal, and even deep neck.^3–8 One report of a case of septic arthritis of the knee caused by B. cepacia complex in a patient and his X-ray showed soft tissue swelling but no discrete fracture.⁹ However, the histopathological examination of the tissue from another case of B. cepacia causing frontal mucopyocele with anterior cranial fossa extension showed the surrounding bone destruction despite brain images with no bone fracture.¹⁰ We encountered an uncommon case of subcutaneous abscess in the right occipital region of a brain-dead woman due to a B. cepacia infection with no special virulence factors. We originally suspected a secondary subcutaneous abscess following an intracranial infection, yet a couple of rounds of CSF examinations showed negative, we then finally confirmed that the abscess with bony destruction was directly caused by B. cepacia. This case demonstrates that B. cepacia without major virulence factors could cause bone injury in immune-compromised patients.

Conclusion

Immunocompromised patients, such as those with AIDS, organ transplantation, long-term hormone treatment, malignant tumors, or diabetes, are at high risks for intracranial infection. Intracranial infection caused by Bacillus cepacia, especially bone destruction, is a rare infection. Early diagnosis and adequate antibiotic therapy could reduce the morbidity of immunocompromised patients suffering from disseminated B. cepacia.