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

Catheter-associated bacteriuria (CAB) with transurethral catheters is almost inevitable. Suprapubic catheters (SPCs) are widely considered to decrease the risk of CAB. However, SPCs are implants similarly prone to microbial biofilm formation. The spectrum of colonising pathogens has not been investigated. The aim of this prospective study was: (1) to assess the diversity of microbial suprapubic catheter colonisation (MSPCC), (2) to identify risk factors and (3) to investigate its association with CAB and catheter-associated urinary tract infection (CA-UTI).

A total of 218 SPCs from 112 patients were studied. Urine specimens were obtained after device replacement or removal. Sonication was performed to dislodge adherent microorganisms. Data of patient sex, age, indwelling time, and underlying disease were recorded.

Sonicate-fluid culture (SFC) detected MSPCC in 95 %. Increasing indwelling time correlated with MSPCC (p < 0.05). Negative SFC was more frequent when antibiotic prophylaxis was applied at time of catheter placement (15 vs. 2 %, p < 0.05). Most commonly isolated were Enterobacteriaceae (45.8 %), followed by Enterococcus spp. (25.7 %) and Pseudomonas aeruginosa (10.3 %). CAB and CA-UTI were observed in 95 and 11 %, respectively.

This study provides the first analysis of MSPCC. Indwelling time increases, whereas antibiotic prophylaxis decreases the risk of MSPCC. The spectrum of pathogens is comparable to the one obtained from urethral catheter biofilms. Urine specimens could not demonstrate the microbial diversity of MSPCC. SPCs are not preferable to urethral catheters to reduce CAB. Whether the risk of CA-UTI could be minimised by SPCs remains to be clarified.