Article
Sonication improves the detection of microorganisms in ventriculo-peritoneal shunt associated infections
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Published: | June 9, 2017 |
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Objective: Antimicrobial treatment of ventriculo-peritoneal (VP) shunt infections is challenging when the causative pathogen is unknown. This study evaluates the feasibility of sonication of explanted shunts to improve the microbiological detection rate.
Methods: All consecutive patients undergoing revision surgery because of VP shunt infection from January 2015 until October 2016 were evaluated. Intraoperative tissue samples, wound swabs and cerebrospinal fluid (CSF) were collected for microbiological examination. The removed implants were additionally sent for sonication to detect biofilm bacteria.
Results: We included 25 patients with a shunt infection with a median age of 51 years (16-82), 40 % were male (n=10). In 12 patients tissue samples, CSF and wound swabs were analyzed, in 13 patients the explanted shunt was additionally sent for sonication. All 13 sonicate cultures showed a positive microbiological result (100%), whereas in cases with conventional microbiological methods the causative microorganism was identified only in 50% (6 out of 12) (p=0,002). If analyzed by method, all 13 sonicate cultures (100%) were positive and 12 out of 25 conventional microbiological analysis results (48%) detected the causative agent (p=0,001.) In 16 patients (64%), antimicrobial treatment was started preoperatively. In those patients, the pathogen was detected in all 9 sonicate cultures (100%), whereas conventional methods grew pathogen only in 28.6% (2/7) (p=0,001) .
Conclusion: In VP shunt-associated infections all sonicate cultures grew the causative pathogen, despite prior antimicrobial treatment, whereas the microbiological yield with conventional methods was statistically significantly lower, regardless whether patients received prior antimicrobial treatment or not. The implementation of sonication for removed VP shunts into the clinical routine may substantially increase the rate of pathogen detection and allow pathogen- and susceptibility-adapted treatment, thereby potentially improving the treatment outcome.