Propionibacterium Acnes: Cause of Cerebrospinal Fluid Shunt Infection

Bacteria commonly associated with central nervous system catheter infections elicit distinct CSF proteome signatures

Background

Cerebrospinal fluid (CSF) shunt infection is a common and devastating complication of the treatment of hydrocephalus. Timely and accurate diagnosis is essential as these infections can lead to long-term neurologic consequences including seizures, decreased intelligence quotient (IQ) and impaired school performance in children. Currently the diagnosis of shunt infection relies on bacterial culture; however, culture is not always accurate since these infections are frequently caused by bacteria capable of forming biofilms, such as Staphylococcus epidermidis, Cutibacterium acnes, and Pseudomonas aeruginosa resulting in few planktonic bacteria detectable in the CSF. Therefore, there is a critical need to identify a new rapid, and accurate method for diagnosis of CSF shunt infection with broad bacterial species coverage to improve the long-term outcomes of children suffering from these infections.

Methods

To investigate potential biomarkers that would discriminate S. epidermidis, C. acnes and P. aeruginosa central nervous system (CNS) catheter infection we leveraged our previously published rat model of CNS catheter infection to perform serial CSF sampling to characterize the CSF proteome during these infections compared to sterile catheter placement.

Results

P. aeruginosa infection demonstrated a far greater number of differentially expressed proteins when compared to S. epidermidis and C. acnes infection and sterile catheters, and these changes persisted throughout the 56-day time course. S. epidermidis demonstrated an intermediate number of differentially expressed proteins, primarily at early time points that dissipated over the course of infection. C. acnes induced the least amount of change in the CSF proteome when compared to the other pathogens.

Conclusions

Despite the differences in the CSF proteome with each organism compared to sterile injury, several proteins were common across all bacterial species, especially at day 5 post-infection, which are candidate diagnostic biomarkers.

Cutibacterium acnes Central Nervous System Catheter Infection Induces Long-Term Changes in the Cerebrospinal Fluid Proteome

Cutibacterium acnes is the third most common cause of cerebrospinal fluid (CSF) shunt infection and is likely underdiagnosed due to the difficulty in culturing this pathogen. Shunt infections lead to grave neurologic morbidity for patients especially when there is a delay in diagnosis. Currently, the gold standard for identifying CSF shunt infections is microbiologic culture. However, C. acnes infection often results in falsely negative cultures; therefore, new diagnostic methods are needed. To investigate potential CSF biomarkers of C. acnes CSF shunt infection we adapted a rat model of CSF catheter infection to C. acnes. We found elevated levels of interleukin-1β (IL-1β), IL-6, chemokine ligand 2, and IL-10 in the CSF and brain tissues of animals implanted with C. acnes-infected catheters compared to sterile controls at day 1 postinfection. This coincided with modest increases in neutrophils in the CSF and, to a greater extent, in the brain tissues of animals with C. acnes infection, which closely mirrors the clinical findings in patients with C. acnes shunt infection. Mass spectrometry revealed that the CSF proteome is altered during C. acnes shunt infection and changes over the course of disease, typified at day 1 postinfection by an acute-phase and pathogen neutralization response evolving to a response consistent with wound resolution at day 28 compared to a sterile catheter placement. Collectively, these results demonstrate that it is possible to distinguish C. acnes infection from sterile postoperative inflammation and that CSF proteins could be useful in a diagnostic strategy for this pathogen that is difficult to diagnose.

Recurrent Shoulder Tip Pain After Ventriculoperitoneal Shunt Placement Associated with Infectious Peritonitis with Propionibacterium acnes; A Case Report and Review of the Literature

Ventriculoperitoneal (VP) shunt placement is commonly performed for the treatment of hydrocephalus, and several complications of this procedure are well known. Radiating shoulder tip pain after VP shunt placement has been reported as an unusual complication in a few cases, associated with dislocation of the peritoneal catheter. We described the case of a 9-year-old girl who presented with recurrent radiating shoulder tip pain after VP shunt placement. The pain recurred after peritoneal catheter repositioning because of peritoneal inflammation and adhesion due to peritonitis with Propionibacterium acnes (P. acnes). This bacterium was isolated using 16S ribosomal RNA gene polymerase chain reaction (16S rRNA gene PCR), and anaerobic and prolonged culture tests. After antibacterial treatment, ventriculoarterial (VA) shunt placement was successfully performed. Hemidiaphragm irritation by the peritoneal catheter leads to radiating shoulder tip pain, and peritoneal inflammation and adhesion caused by infectious peritonitis may cause recurrence of this despite catheter repositioning. Clinicians should be aware of shoulder pain as a complication of VP shunt placement, and should consider VA shunt placement as an alternative treatment if this symptom recurs after catheter repositioning. Furthermore, 16S rRNA gene PCR and anaerobic and prolonged culture tests should be considered to detect P. acnes infection.