Sonication Improves Pathogen Detection in Ventriculoperitoneal Shunt-Associated Infections.

Abstract

Antimicrobial treatment of ventriculoperitoneal (VP) shunt infections is challenging when the causative pathogen is unknown. To evaluate the value of sonication of explanted shunt-devices to improve the microbiological detection rate. All consecutive patients undergoing revision surgery due to suspected VP-shunt infection from January 2015 to February 2017 were evaluated. Intraoperative tissue samples, wound swabs, and cerebrospinal fluid (CSF) were collected for microbiological examination. In a subgroup of patients, the removed implants were additionally sent for sonication. A total of 35 patients were included with a mean age of 57.5 ± 18 yr, 21 were female (60%). In 13 patient's tissue samples, CSF and wound swabs were analyzed. In 22 patients, the explanted device was additionally sent for sonication. All 22 sonication cultures showed a positive microbiological result (100%), whereas with conventional microbiological methods, the causative microorganism was identified in 8 of 13 (61%; P = .018). Analyzed by method, all 22 sonication cultures (100%) were positive and 21 of 35 conventional microbiological analysis results (60%) detected the causative agent (P < .001.) In 18 patients (51%), antimicrobial treatment was started preoperatively. In those patients, the pathogen was detected in all 12 sonication cultures (100%), whereas conventional methods grew a pathogen in 3 of 6 patients (P = .005). Sonication significantly increases the microbiological yield in VP-shunt infections, especially in patients receiving antibiotics prior to diagnostics and in infections caused by low-virulent organisms. The implementation of sonication into the clinical routine can substantially increase the rate of pathogen detection allowing targeted treatment.