New perspectives on the surgical treatment of posterior urethral obstruction.

PURPOSE OF REVIEW: Posterior urethral obstruction (PUO) from prostate surgery for benign and malignant conditions poses a significant reconstructive challenge. Endoscopic management demonstrates only modest success and often definitive reconstructive solutions are necessary to limit morbidity and firmly establish posterior urethral continuity. This often demands a combined abdominoperineal approach, pubic bone resection, and even sacrifice of the external urinary sphincter and anterior urethral blood supply. Recently, a robotic-assisted approach has been described. Enhanced instrument dexterity, magnified visualization, and adjunctive measures to assess tissue quality may enable the reconstructive surgeon to engage posterior strictures deep within the confines of the narrow male pelvis and optimize functional outcomes. The purpose of this review is to review the literature regarding endoscopic, open, and robotic management outcomes for the treatment of PUO, and provide an updated treatment algorithm based upon location and complexity of the stricture. RECENT FINDINGS: Contingent upon etiology, small case series suggest that robotic bladder neck reconstruction has durable reconstructive outcomes with acceptable rates of incontinence in carefully selected patients. SUMMARY: Initial reports suggest that robotic bladder neck reconstruction for recalcitrant PUO may offer novel reconstructive solutions and durable function outcomes in select patients.

Parameters for the mathematical modelling of Clostridium difficile acquisition and transmission: a systematic review.

INTRODUCTION: Mathematical modelling of Clostridium difficile infection dynamics could contribute to the optimisation of strategies for its prevention and control. The objective of this systematic review was to summarise the available literature specifically identifying the quantitative parameters required for a compartmental mathematical model of Clostridium difficile transmission. METHODS: Six electronic healthcare databases were searched and all screening, data extraction and study quality assessments were undertaken in duplicate. Results were synthesised using a narrative approach. RESULTS: Fifty-four studies met the inclusion criteria. Reproduction numbers for hospital based epidemics were described in two studies with a range from 0.55 to 7. Two studies provided consistent data on incubation periods. For 62% of cases, symptoms occurred in less than 4 weeks (3-28 days) after infection. Evidence on contact patterns was identified in four studies but with limited data reported for populating a mathematical model. Two studies, including one without clinically apparent donor-recipient pairs, provided information on serial intervals for household or ward contacts, showing transmission intervals of <1 week in ward based contacts compared to up to 2 months for household contacts. Eight studies reported recovery rates of between 75%-100% for patients who had been treated with either metronidazole or vancomycin. Forty-nine studies gave recurrence rates of between 3% and 49% but were limited by varying definitions of recurrence. No study was found which specifically reported force of infection or net reproduction numbers. CONCLUSIONS: There is currently scant literature overtly citing estimates of the parameters required to inform the quantitative modelling of Clostridium difficile transmission. Further high quality studies to investigate transmission parameters are required, including through review of published epidemiological studies where these quantitative estimates may not have been explicitly estimated, but that nonetheless contain the relevant data to allow their calculation.

Spread of Pseudomonas fluorescens due to contaminated drinking water in a bone marrow transplant unit.

Pseudomonas infections are an important cause of morbidity and mortality in immunocompromised patients. We present here data for the spread of Pseudomonas fluorescens caused by a contaminated drinking water dispenser in a bone marrow transplant unit. Over a 1-month period we observed a sharp increase in the isolation of P. fluorescens from weekly pharyngeal surveillance swabs. Environmental samples were taken from a variety of water sources throughout the unit. These samples were cultured on cetrimide agar medium, and isolates were epidemiologically characterized by antibiotic susceptibility patterns and molecular typing methods. Nine patients became colonized with P. fluorescens, and six out of the nine developed febrile neutropenia. P. fluorescens was cultured after the filtration of 100 ml of drinking water from one of two stand-alone chiller units supplying cooled bottled water to the bone marrow transplant unit. All other environmental samples were negative. There were no further cases of P. fluorescens colonization after the contaminated dispenser was removed. Molecular typing showed that all P. fluorescens isolates were identical by both random amplification of polymorphic DNA PCR and pulsed-field gel electrophoresis. We recommend that such bottled water supplies not be used in high-risk areas or be subject to regular microbiological monitoring.