Improved detection of microbial ureteral stent colonisation by sonication

Abstract

Purpose The diagnosis of microbial ureteral stent colonisation (MUSC) is difficult, since routine diagnostic techniques do not accurately detect microorganisms embedded in biofilms. New methods may improve diagnostic yield and understanding the pathophysiology of MUSC. The aim of the present study was to evaluate the potential of sonication in the detection of MUSC and to identify risk factors for device colonisation. Methods Four hundred and eight polyurethane ureteral stents of 300 consecutive patients were prospectively evaluated. Conventional urine culture (CUC) was obtained prior to stent placement and device removal. Sonication was performed to dislodge adherent microorganisms. Data of patient sex and age, indwelling time and indication for stent placement were recorded. Results Sonicate-fluid culture detected MUSC in 36%. Ureteral stents inserted during urinary tract infection (UTI) were more frequently colonised (59%) compared to those placed in sterile urine (26%; P \ 0.001). Female sex (P \ 0.001) and continuous stenting (P \ 0.005) were significant risk factors for MUSC; a similar trend was observed in patients older than 50 years (P = 0.16). MUSC and indwelling time were positively correlated (P \ 0.005). MUSC was accompanied by positive CUC in 36%. Most commonly isolated microorganisms were Coagulase-negative staphylococci (18.3%), Enterococci (17.9%) and Enterobacteriaceae (16.9%). Conclusions Sonication is a promising approach in the diagnosis of MUSC. Significant risk factors for MUSC are UTI at the time of stent insertion, female sex, continuous stenting and indwelling time. CUC is a poor predictor of MUSC. The clinical relevance of MUSC needs further evaluation to classify isolated microorganism properly as contaminants or pathogens.

Sonication cultures of explanted components as an add‐on test to routinely conducted microbiological diagnostics improve pathogen detection

“…In the literature experiences with the sonication method to dislodge biofilm from explanted devices were presented with good results in diverse surgical fields. [25][26][27][28] Our study confirmed these results: by the use of the SC a significant increase of pathogen was seen in recovery compared to the TC with two or more positive cultures (83.3% vs. 61.1%, p ¼ 0.034). However, if single positive TC was considered to represent a positive TC result for infection, no significant difference between the sensitivity of TC compared to that of the SC was provable (72.2% vs. 83.3%, p ¼ 0.5) which was similar to the results of the original study by Trampuz et al 22 (73.4% vs. 78.5%, p ¼ 0.21).…”

Sonication of Explanted Cardiac Implants Improves Microbial Detection in Cardiac Device Infections

“…The collected samples were inoculated in TSB and incubated for 24 h at 37°C. After the removal of TSB, each device was further covered with Ringer's solution and vortexed for 30 s; then, samples were sonicated for 5 min at a frequency of Ͼ20 kHz and vortexed again for 30 s (20,25,30,33). A BactoSonic apparatus (Bandelin Electronic GmbH & Co. KG, Berlin, Germany) was used for sonication.…”

“…The poor sensitivity of conventional microbiological methods is mainly due to the occurrence of adherent bacteria that are encased in biofilms on the surface of the implanted device (19). The sonication technique, which is based on the application of long-wave ultrasound, has been used in order to enhance bacterial detection by liberating sessile organisms embedded in biofilms on foreign bodies (20)(21)(22)(23)(24). In particular, the sonication of removed implants has been introduced in clinical practice and has shown good results for the microbiological diagnosis of device-related orthopedic infections (25)(26)(27), whereas its application in the setting of CDIs is still limited.…”

Microbial biofilm formation and catheter-associated bacteriuria in patients with suprapubic catheterisation

“…These parts were placed in sterile tubes and processed by the microbiology laboratory within 6 h. Negative controls (n = 8) consisted of unused sterile SPCs unpacked in the operation room and sent for sonication to go through the same process as SPCs removed from the patients. Catheter colonisation was detected by sonication as described previously [7][8][9][10].…”

“…In addition, the influence of individual risk factors from patients as well as different indications for SPC placement was evaluated. In this study, we were using both conventional urine culture and sonication as recently published [7][8][9].…”