A review of methods to determine viability, vitality and metabolic rates in microbiology

Viability and metabolic assays are commonly used as proxies to assess the overall metabolism of microorganisms. The variety of these assays combined with little information provided by some assay kits or online protocols often leads to mistakes or poor interpretation of the results. In addition, the use of some of these assays is restricted to simple systems (mostly pure cultures), and care must be taken in their application to environmental samples. In this review, the necessary data are compiled to understand the reactions or measurements performed in many of the assays commonly used in various aspects of microbiology. Also, their relationships to each other, as metabolism links many of these assays, resulting in correlations between measured values and parameters, are discussed. Finally, the limitations of these assays are discussed

Complications of laser prostatectomy: a review of recent data

Introduction: Laser techniques for the treatment of bladder outlet obstruction (BOO) due to benign prostate enlargement (BPE) have emerged as an alternative to transurethral resection of the prostate (TURP) and open prostatectomy (OP). Materials and methods: A Medline search over the past 4years was performed to assess the safety, intra- and postoperative morbidity of various laser techniques. Results: Data on holmium laser enucleation of the prostate (HoLEP) show the highest grade of evidence with two meta-analyses available and prove the low intra- and postoperative morbidity with reproducible long-term results. Photoselective vaporization of the prostate (PVP) with the Greenlightlaser (potassium titanyl phosphate, KTP or lithium borate, LBO) is characterized by excellent haemostatic properties in patients with or without oral anticoagulation. Long-term results show a reoperation rate comparable with TURP; however, there is a lack of randomized trials. Various types of diode lasers with different wavelengths are available for laser vaporization; despite their favourable haemostatic properties, a higher invasion depth seems to result in necrosis of the tissue leading to a higher rate of reoperation. Thulium-laser resection of the prostate shows promising intra- and postoperative morbidity, but data are limited and initial results need to be confirmed in large-scale trials. Conclusion: In summary, HoLEP- and KTP-, or LBO-laser vaporization of the prostate are the most mature techniques of laser prostatectomy and treatment alternatives to TURP and OP, whereas the clinical value and durability of procedures with diode laser systems and the thulium laser need to be confirmed in high-quality prospective RCT

Benigne zystische Raumforderungen des Hodens: Eine Übersicht

Zusammenfassung: Hodenzysten werden im Rahmen der skrotalen Sonographie zunehmend diagnostiziert. Grund hierfür ist u.a. die flächendeckende Verfügbarkeit moderner, hochauflösender Ultraschallgeräte. Differentialdiagnostisch und ätiologisch sind benigne und maligne Erkrankungen mit testikulärer Zystenbildung voneinander zu unterscheiden. Benigne Krankheitsbilder mit zystischen Raumforderungen des Hodens sind die tubuläre Ektasie des Rete testis, die zystische Dysplasie, Epidermoidzysten, einfache intraparenchymatöse Hodenzysten und Zysten der Tunica albuginea. Die testikuläre Dermoidzyste, die lange Zeit zu Unrecht als potentiell maligne angesehen wurde, ist ebenfalls als benigne zu klassifizieren. Bei Diagnose einer benignen zystischen Raumforderung des Hodens kann in den meisten Fällen eine organerhaltende operative Therapie oder ein abwartendes, überwachendes Procedere empfohlen werde

Diagnostik und Therapie der Harnleitersteinkolik

Summary: Acute ureteral colic presents with a complex of acute and characteristic flank pain that usually indicates the presence of a stone in the urinary tract. Diagnosis and management of renal colic have undergone considerable evolution and advancement in recent years. The application of noncontrast helical computed tomography (CT) in patients with suspected ureteral colic is one major advance in the primary diagnostic process. The superior sensitivity and specificity of helical CT allow ureterolithiasis to be diagnosed without the potential side effects of contrast media. Initial management is based on three key concepts: (A) rational and fast diagnostic process (B) effective pain control (C) and understanding of the impact of stone location and size on the natural course of the disease and definitive urologic management. These concepts are discussed in this review with reference to contemporary literatur

Microbial colonization and ureteral stent-associated storage lower urinary tract symptoms: the forgotten piece of the puzzle?

Purpose: Ureteral stents are frequently associated with side effects. Most patients suffer from storage lower urinary tract symptoms (LUTS). Storage LUTS are commonly attributed to the irritation of the trigone, smooth muscle spasm or a combination of factors. The relationship between microbial ureteral stent colonization (MUSC) and de novo or worsening storage LUTS has not been investigated yet. Methods: Five hundred ninety-one polyurethane ureteral stents from 275 male and 153 female patients were prospectively evaluated. The removed stents were sonicated to dislodge adherent microorganisms. Urine flow cytometry was performed to detect pyuria. A standardized urinary symptom questionnaire was given to all patients. Results: Thirty-five per cent of male and 28% of female cases showed de novo or worsened storage LUTS. MUSC was more common in patients with storage LUTS compared to patients without storage LUTS (men: 26 vs. 13%, respectively, P<0.05; women: 63 vs. 48%, respectively, P=0.13). Pyuria was significantly more common in patients with storage LUTS compared to patients without storage LUTS (men: 55 vs. 40%, respectively, P<0.05; women: 70 vs. 45%, respectively, P<0.05). No significant correlation was observed between the detected genera of microorganisms and storage LUTS. Conclusions: Our data show a significant association between MUSC- and stent-related de novo experienced or worsened storage LUTS in men. The incidence of MUSC is most common in both female and male patients with storage LUTS and accompanying pyuria. In these patients, a combination of antibiotics and anti-inflammatory drugs may be regarded as treatment optio

Improved detection of microbial ureteral stent colonisation by sonication

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 50years (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 pathogen

Standardization of isothermal microcalorimetry in urinary tract infection detection by using artificial urine

Purpose: Isothermal microcalorimetry (IMC) has recently been reported as a new method to rapidly detect urinary tract pathogens (UTP). However, further application of microcalorimetry in the clinical setting requires a standardized procedure. An important step toward such standardization is to use a reproducible growth medium. In this study, we investigated the potential of artificial urine in combination with microcalorimetry for detection of common UTP. Methods: A microcalorimeter equipped with 48 channels was used. Detection was accomplished, and growth was monitored for four bacterial strains in artificial urine at 37°C by measuring metabolic heat flow (μW=μJ/s) as a function of time. The strains were Escherichia coli, Proteus mirabilis, Enterococcus faecalis, and Staphylococcus aureus. Result: Bacterial growth was detected after 3-32h with decreasing inoculums down to 1CFU. The gram-negative strains grew and were detected faster than their gram-positive counterparts. The growth rates the different strains were 0.75±0.11 for E. coli, 0.74±0.10 for E. faecalis, 1.31±0.04 for P. mirabilis, and 0.56±0.20 for S. aureus. The shape of individual heat flow curves was characteristic for each species independent of its initial concentration. Conclusions: IMC allows rapid detection of UTP in artificial urine. Clearly, different heat flow patterns enable accurate pathogen differentiation. UTP detection after only 4h is realistic. The rapid detection of UTP tested in standardized artificial urine proves the diagnostic potential of IMC and warrants further microcalorimetric studies in the clinical setting of urinary tract infection

Improved detection of microbial ureteral stent colonisation by sonication

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 50years (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 pathogen

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

Purpose: 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). Methods: 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. Results: 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. Conclusions: 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 clarifie