Heterogeneity of SOS response expression in clinical isolates of Escherichia coli influences adaptation to antimicrobial stress.

In recent years, new evidence has shown that the SOS response plays an important role in the response to antimicrobials, with involvement in the generation of clinical resistance. Here we evaluate the impact of heterogeneous expression of the SOS response in clinical isolates of Escherichia coli on response to the fluoroquinolone, ciprofloxacin. In silico analysis of whole genome sequencing data showed remarkable sequence conservation of the SOS response regulators, RecA and LexA. Despite the genetic homogeneity, our results revealed a marked differential heterogeneity in SOS response activation, both at population and single-cell level, among clinical isolates of E. coli in the presence of subinhibitory concentrations of ciprofloxacin. Four main stages of SOS response activation were identified and correlated with cell filamentation. Interestingly, there was a correlation between clinical isolates with higher expression of the SOS response and further progression to resistance. This heterogeneity in response to DNA damage repair (mediated by the SOS response) and induced by antimicrobial agents could be a new factor with implications for bacterial evolution and survival contributing to the generation of antimicrobial resistance.

Enhanced Antibacterial Activity of Repurposed Mitomycin C and Imipenem in Combination with the Lytic Phage vB_KpnM-VAC13 against Clinical Isolates of Klebsiella pneumoniae.

Klebsiella pneumoniae is an opportunistic Gram-negative pathogen that employs different strategies (resistance and persistence) to counteract antibiotic treatments. This study aimed to search for new means of combatting imipenem-resistant and persister strains of K. pneumoniae by repurposing the anticancer drug mitomycin C as an antimicrobial agent and by combining the drug and the conventional antibiotic imipenem with the lytic phage vB_KpnM-VAC13. Several clinical K. pneumoniae isolates were characterized, and an imipenem-resistant isolate (harboring OXA-245 ß-lactamase) and a persister isolate were selected for study. The mitomycin C and imipenem MICs for both isolates were determined by the broth microdilution method. Time-kill curve data were obtained by optical density at 600 nm (OD600) measurement and CFU enumeration in the presence of each drug alone and with the phage. The frequency of occurrence of mutants resistant to each drug and the combinations was also calculated, and the efficacy of the combination treatments was evaluated using an in vivo infection model (Galleria mellonella). The lytic phage vB_KpnM-VAC13 and mitomycin C had synergistic effects on imipenem-resistant and persister isolates, both in vitro and in vivo. The phage-imipenem combination successfully killed the persisters but not the imipenem-resistant isolate harboring OXA-245 ß-lactamase. Interestingly, the combinations decreased the emergence of in vitro resistant mutants of both isolates. Combinations of the lytic phage vB_KpnM-VAC13 with mitomycin C and imipenem were effective against the persister K. pneumoniae isolate. The lytic phage-mitomycin C combination was also effective against imipenem-resistant K. pneumoniae strains harboring OXA-245 ß-lactamase.

Comparative Study of the Influence of Three-Dimensional Versus Two-Dimensional Urological Laparoscopy on Surgeons' Surgical Performance and Ergonomics: A Systematic Review and Meta-Analysis.

Objective: The objective of this study is to compare the use of three-dimensional (3D) vision systems with traditional two-dimensional systems in laparoscopic urological surgery, analyzing the benefits, limitations, and impact of introducing this medical technology with regard to surgical performance and the surgeon's ergonomics. Methods: A systematic review with a structured bibliographic search was conducted in the electronic libraries (PubMed and EMBASE) until August 2019 and with no language restrictions. Studies on 3D visualization technology in laparoscopic urologic surgery, randomized controlled trials, and observational comparative studies were included. Relevant data were extracted and analyzed. Results: A total of 25 articles were obtained, of which 4 were clinical studies with patients, 2 studies were carried out in experimental animal models, and the remaining 19 were conducted in simulated environments. Regarding the European training program in basic laparoscopic urological skills, the results showed no significant differences in execution time using either imaging system. Three-dimensional vision led to a significant reduction in surgery time in pyeloplasty and radical nephrectomy. In addition, there was a reported decrease in blood loss in adrenalectomy, nephron-sparing nephrectomy, radical nephrectomy, simple nephrectomy, and pyeloplasty using 3D vision. Regarding ergonomics, the studies generally described no differences in side effects (headache, nausea, eye strain) when comparing the two types of visualization systems. Surgeons reported reduced workloads and stress with 3D vision than with traditional laparoscopy. Conclusions: Three-dimensional laparoscopic systems essentially advance surgical performance in less-experienced laparoscopic surgeons. Three-dimensional laparoscopy leads to improvements in surgery time, which is important for specific surgical procedures involving intracorporeal ligatures and sutures. The results achieved on the surgeons' ergonomics showed better depth perception and decreased stress and workloads during 3D vision with no differences in potential side effects.

Validation of a Novel, Sensitive, and Specific Urine-Based Test for Recurrence Surveillance of Patients With Non-Muscle-Invasive Bladder Cancer in a Comprehensive Multicenter Study.

Bladder cancer (BC), the most frequent malignancy of the urinary system, is ranked the sixth most prevalent cancer worldwide. Of all newly diagnosed patients with BC, 70-75% will present disease confined to the mucosa or submucosa, the non-muscle-invasive BC (NMIBC) subtype. Of those, approximately 70% will recur after transurethral resection (TUR). Due to high rate of recurrence, patients are submitted to an intensive follow-up program maintained throughout many years, or even throughout life, resulting in an expensive follow-up, with cystoscopy being the most cost-effective procedure for NMIBC screening. Currently, the gold standard procedure for detection and follow-up of NMIBC is based on the association of cystoscopy and urine cytology. As cystoscopy is a very invasive approach, over the years, many different noninvasive assays (both based in serum and urine samples) have been developed in order to search genetic and protein alterations related to the development, progression, and recurrence of BC. TERT promoter mutations and FGFR3 hotspot mutations are the most frequent somatic alterations in BC and constitute the most reliable biomarkers for BC. Based on these, we developed an ultra-sensitive, urine-based assay called Uromonitor®, capable of detecting trace amounts of TERT promoter (c.1-124C > T and c.1-146C > T) and FGFR3 (p.R248C and p.S249C) hotspot mutations, in tumor cells exfoliated to urine samples. Cells present in urine were concentrated by the filtration of urine through filters where tumor cells are trapped and stored until analysis, presenting long-term stability. Detection of the alterations was achieved through a custom-made, robust, and highly sensitive multiplex competitive allele-specific discrimination PCR allowing clear interpretation of results. In this study, we validate a test for NMIBC recurrence detection, using for technical validation a total of 331 urine samples and 41 formalin-fixed paraffin-embedded tissues of the primary tumor and recurrence lesions from a large cluster of urology centers. In the clinical validation, we used 185 samples to assess sensitivity/specificity in the detection of NMIBC recurrence vs. cystoscopy/cytology and in a smaller cohort its potential as a primary diagnostic tool for NMIBC. Our results show this test to be highly sensitive (73.5%) and specific (93.2%) in detecting recurrence of BC in patients under surveillance of NMIBC.

Predictive value of the kinetics of procalcitonin and C-reactive protein for early clinical stability in patients with bloodstream infections due to Gram-negative bacteria.

OBJECTIVE: To investigate whether the magnitude of the change in procalcitonin (PCT) and C-reactive protein (CRP) levels between day 1 and day 2 after the blood culture date is associated with early clinical stability (ECS) on day 3 in patients with bacteremia due to Gram-negative bacteria (GNB). MATERIALS/METHODS: A prospective cohort study carried out in a 950-bed tertiary hospital in Spain between March 2013 and May 2014. Patients with GNB bacteremia were included. Changes in PCT and CRP kinetics from day 1 to day 2 (∆%PCT, ∆%CRP) were expressed as percentage of decline in blood levels. Logistic regression was used to identify predictors of ECS. Classification and regression tree analysis was performed to identify breakpoints. The discriminatory power of ∆%CRP and ∆%PCT as predictors of ECS was assessed by the area under the ROC (AUROC). RESULTS: 71 patients were included, and 53 (74.56%) reached ECS. Multivariate analyses showed that SOFA score on day 1, ∆%PCT, and ∆%CRP were associated with ECS after controlling for confounders. ∆%PCT ≥ 30% (decline) and ∆%CRP ≥ 10% (decline) predicted ECS only among patients with SOFA≤3 on day 1 (n = 54; 43 reached ECS). In these patients, the AUROCs for the prediction of ECS were 0.96 (95% CI: 0.90-1) for ∆%CRP and 0.96 (95% CI: 0.90-1) for ∆%PCT, respectively. CONCLUSIONS: In the subgroup of patients with a SOFA score on day 1 ≤3, a ≥30% decline in PCT or a ≥10% decline in CRP between day 1 and day 2 was a very good predictor of ECS (which in turn was associated with a lower 30-day mortality and a greater clinical cure on day 14). Patients who do not achieve this decrease may need more intensive workup. In this subgroup (with a SOFA on day 1 ≤3), CRP may be preferred due to its lower cost.

Cost-Effectiveness Analysis of Bezlotoxumab Added to Standard of Care Versus Standard of Care Alone for the Prevention of Recurrent Clostridium difficile Infection in High-Risk Patients in Spain.

INTRODUCTION: Clostridium difficile infection (CDI) is the major cause of infectious nosocomial diarrhoea and is associated with considerable morbidity, mortality and economic impact. Bezlotoxumab administered in combination with standard of care (SoC) antibiotic therapy prevents recurrent CDI. This study assessed the cost-effectiveness of bezlotoxumab added to SoC, compared to SoC alone, to prevent the recurrence of CDI in high-risk patients from the Spanish National Health System perspective. METHODS: A Markov model was used to simulate the natural history of CDI over a lifetime horizon in five populations of patients at high risk of CDI recurrence according to MODIFY trials: (1) ≥ 65 years old; (2) severe CDI; (3) immunocompromised; (4) ≥ 1 CDI episode in the previous 6 months; and (5) ≥ 65 years old and with ≥ 1 CDI episode in the previous 6 months. The incremental cost-effectiveness ratio (ICER) expressed as cost per quality-adjusted life-year (QALY) gained was calculated. Deterministic (DSA) and probabilistic sensitivity analyses (PSA) were performed. RESULTS: In all patient populations (from 1 to 5), bezlotoxumab added to SoC reduced CDI recurrence compared to SoC alone by 26.4, 19.5, 21.2, 26.6 and 39.7%, respectively. The resulting ICERs for the respective subgroups were €12,724, €17,495, €9545, €7386, and €4378. The model parameters with highest impact on the ICER were recurrence rate (first), mortality, and utility values. The probability that bezlotoxumab was cost-effective at a willingness-to-pay threshold of €21,000/QALY was 85.5%, 54.1%, 86.0%, 94.5%, 99.6%, respectively. CONCLUSION: The results suggest that bezlotoxumab added to SoC compared to SoC alone is a cost-effective treatment to prevent the recurrence of CDI in high-risk patients. The influence of changes in model parameters on DSA results was higher in patients ≥ 65 years old, with severe CDI and immunocompromised. Additionally, PSA estimated that the probability of cost-effectiveness exceeded 85% in most subgroups. FUNDING: Merck Sharp & Dohme Corp.

[Training in basic and advanced laparoscopy: Evaluation of a 30-year experience in a training program in Spain.] / Formación en cirugía laparoscópica urológica básica y avanzada: evaluación de 30 años de experiencia de un programa de formación en España.

The lack of globally established standards for learning urological laparoscopy has not prevented laparoscopic techniques from evolution and continuous development. Laparoscopy coexists with robotic surgery today, and in the last decade there have been many techniques that have undergone a boom with the use of a laparoscopic approach (total and partial nephrectomy, pyeloplasty, colposacropexy, etc.).We intend to evaluate the progressive incorporation of different surgical techniques in the laparoscopic learning program and, on the other hand, to analyze the evolution of training programs in urological laparoscopy to bring this type of techniques within the hospital surgical activity. We describe our 30-years experience in different training programs in urological laparoscopy that have been sponsored by the Spanish Association of Urology (AEU), and have undergone several validity studies to assess their capacity in order to evaluate effectively basic and advanced laparoscopic skills. We will also highlight the current and future trend towards training models based on surgical competences where individualized training, accreditation and specialization of tutors is crucial, and where the increase in the use of training and evaluation methods based on the simulation are increasingly common.

Disección aneurismática del tronco celíaco, una entidad infrecuente / Isolated celiac trunk aneurysm dissection: A rare entity / Dissecção aneurismática do tronco celíaco, uma entidade infrequente

RESUMEN La disección aislada y espontánea de la arteria celíaca es una entidad clínica rara. Es la cuarta causa de aneurismas abdominales por detrás de los que ocurren en las arterias esplénica, hepática y mesentérica superior. Es importante sospechar el diagnóstico de esta enfermedad cuyos síntomas son inespecíficos. Presentamos el caso de un varón de 60 años de edad atendido en nuestro hospital por esta enfermedad, y hacemos una revisión del tema con énfasis en el diagnóstico y en los diferentes tratamientos disponibles.

SUMMARY Spontaneous and isolated celiac artery dissection is a rare clinical disease. It is the fourth cause of abdominal aneurysms behind those that occur in the splenic, hepatic, and superior mesenteric arteries. It is important to suspect the diagnosis of this entity whose clinical symptoms are unspecific. We report the case of a 60 year-old male treated in our hospital because of this illness, and present a review of this pathology, specially focused on the diagnosis and the different treatments available.

RESUMO A dissecção isolada e espontânea da artéria celíaca é uma entidade clínica rara. É a quarta causa de aneurismas abdominais por detrás dos que ocorrem nas artérias esplénica, hepática e mesentérica superior. É importante suspeitar o diagnóstico desta doença cujos sintomas são inespecíficos. Apresentamos o caso de um homem de 60 anos de idade atendido no nosso hospital por esta doença, e fazemos uma revisão do assunto com ênfase no diagnóstico e nos diferentes tratamentos disponíveis.

Bacteraemia due to non-ESBL-producing Escherichia coli O25b:H4 sequence type 131: insights into risk factors, clinical features and outcomes.

The epidemiology and outcomes of bloodstream infections (BSIs) caused by Escherichia coli ST131 isolates not producing extended-spectrum ß-lactamases (ESBLs) are not well defined despite being more prevalent than ESBL-producers. In this study, risk factors and the impact on outcome of BSIs caused by non-ESBL-producing ST131 E. coli versus non-ST131 E. coli were investigated. A case-control study was performed in two tertiary centres to identify risk factors for ST131. Molecular methods were used to investigate all E. coli isolates from blood cultures for those belonging to O25b:H4-ST131 clonal group. fimH alleles were characterised in ST131 isolates. Multivariate analysis was performed by logistic regression or Cox regression as appropriate. A total of 33 ST131 E. coli cases and 56 controls were studied. ST131 isolates showed higher rates of resistance to ampicillin and ciprofloxacin; fimH alleles were H30 in 14 isolates (42.4%) and H22 in 12 isolates (36.4%). Only recent surgery (OR = 7.03, 95% CI 1.71-28.84; P = 0.007) and unknown source of bacteraemia (OR = 5.37, 95% CI 0.93-30.81; P = 0.05) were associated with ST131. ST131 isolates showed no association with 30-day mortality, therapeutic failure, presentation with severe sepsis/shock or length of stay. Bacteraemia due to non-ESBL-producing O25b:H4-ST131 E. coli showed few differences in terms of risk factors as well as similar outcome to non-ST131 E. coli. These data support the notion that ST131 strains are not less clinically virulent despite showing increased antimicrobial resistance, but also that they are not more virulent than other clonal groups causing BSI.

In vitro activity of a polyhexanide-betaine solution against high-risk clones of multidrug-resistant nosocomial pathogens.

OBJECTIVE: To determine the in vitro activity of a polyhexanide-betaine solution against collection strains and multidrug-resistant (MDR) nosocomial isolates, including high-risk clones. METHODS: We studied of 8 ATCC and 21 MDR clinical strains of Staphylococcus aureus, Enterococcus faecium, Enterococcus faecalis, Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa, including the multiresistant high-risk clones. The MICs and MBCs of a 0.1% polyhexanide-0.1% betaine solution were determined by microdilution. For each species, strains with the highest MICs were selected for further experiments. The dilution-neutralization test (PrEN 12054) was performed by incubating bacterial inocula of 106CFU/mL for 1min with undiluted 0.1% polyhexanide-betaine solution. The CFUs were counted after neutralization. Growth curves and time-kill curves at concentrations of 0.25, 1, 4, and 8×MIC, were performed. MICs of recovered strains were determined when regrowth was observed in time-kill studies after 24h of incubation. Strains with reduced susceptibility were selected by serial passage on plates with increasing concentrations of polyhexanide-betaine, and MICs were determined. RESULTS: Polyhexanide-betaine MIC range was 0.5-8mg/L. MBCs equalled or were 1 dilution higher than MICs. The dilution-neutralization method showed total inoculum clearance of all strains. In time-kill curves, no regrowth was observed at 4×MIC, except for S. aureus (8×MIC). Increased MICs were not observed in time-kill curves, or after serial passages after exposure to polyhexanide-betaine. CONCLUSIONS: Polyhexanide-betaine presented bactericidal activity against all MDR clinical isolates tested, including high-risk clones, at significantly lower concentrations and time of activity than those commercially used.

Plasmid-mediated quinolone resistance: Two decades on.

After two decades of the discovery of plasmid-mediated quinolone resistance (PMQR), three different mechanisms have been associated to this phenomenon: target protection (Qnr proteins, including several families with multiple alleles), active efflux pumps (mainly QepA and OqxAB pumps) and drug modification [AAC(6')-Ib-cr acetyltransferase]. PMQR genes are usually associated with mobile or transposable elements on plasmids, and, in the case of qnr genes, are often incorporated into sul1-type integrons. PMQR has been found in clinical and environmental isolates around the world and appears to be spreading. Although the three PMQR mechanisms alone cause only low-level resistance to quinolones, they can complement other mechanisms of chromosomal resistance to reach clinical resistance level and facilitate the selection of higher-level resistance, raising a threat to the treatment of infections by microorganisms that host these mechanisms.

Antimicrobial photodynamic activity of hypericin against methicillin-susceptible and resistant Staphylococcus aureus biofilms.

AIM: To evaluate the effectiveness of the photodynamic therapy using hypericin (HYP) against both planktonic and biofilm-forming Staphylococcus aureus. MATERIALS & METHODS: HYP photoactivity was evaluated against methicillin-susceptible and resistant S. aureus. Bacterial suspension or biofilm were preincubated with HYP and subjected to LED illumination. Viable bacteria were determined by colony counting. RESULTS: Preincubation with HYP (5 min) plus light exposure (10 min) showed bactericidal effect against planktonic methicillin-susceptible S. aureus and methicillin-resistant S. aureus. Longer preincubation times (24 h) and time light exposure (30 min) were required to reach HYP-photoactivity against S. aureus biofilms. HYP-photoactivity was correlated to the biofilm production. CONCLUSION: HYP could be a potential photosensitizer for the inactivation of staphylococcal biofilms forming on the surfaces accessible to visible light.

[Training and research in urologic laparoscopic surgery. Design of training programs and experimental models of renal tumor]. / Formación e investigación en cirugía laparoscópica urológica. Diseño de programas formativos y modelos experimentales de tumor renal.

We present our experience with surgical training programs development for basic and advanced laparoscopic urological surgery. Both training programs consist of 21 and 28 hours respectively. Basic surgical programs start with general knowledge of ergonomics and instrumentation, there after, attendants acquire basic skills on physical simulator. Posteriorly, techniques on animal model are undertaken, always assisted by an expert. Advanced activities start with surgical tasks on physical simulator. Posteriorly, reconstructive urological surgical techniques are undertaken on animal model, focused on partial nephrectomy, and always assisted by an expert tutor. We present our results on exophytic renal tumour model creation based chromatic Alginate.

Epidemiological and clinical features associated with colonisation/infection by Acinetobacter baumannii with phenotypic heterogeneous resistance to carbapenems.

The objective of this study was to identify risk factors for the acquisition of Acinetobacter baumannii with phenotypic heterogeneous resistance (PHR) to carbapenems and to determine whether these factors are similar to those associated with A. baumannii not showing this phenotype. Microbiological and clinical data from 211 patients included in the GEIH-Ab 2000 project were used. Isolates of A. baumannii were studied for their susceptibility to imipenem (IPM) by microdilution and for PHR to IPM as determined by the presence of colonies growing within the inhibition zone of IPM disks. Isolates were divided into three groups: (i) IPM-PHR isolates, i.e. susceptible and non-susceptible A. baumannii displaying PHR to IPM; (ii) non-IPM-PHR isolates, i.e. susceptible A. baumannii showing an inhibition halo but no colonies growing within it; and (iii) IPM-FR isolates, i.e. fully resistant A. baumannii displaying no halo of inhibition. IPM-PHR isolates of A. baumannii were more commonly isolated from respiratory tract samples and less commonly from urine, and were more frequently causes of infection than were IPM-FR isolates. Independent risk factors identified in patients with IPM-PHR isolates were Intensive Care Unit admission, surgery, and previous use of piperacillin/tazobactam or carbapenems, whilst risk factors for IPM-FR and IPM-PHR were previous use of cephalosporins and isolation from a urine sample. In conclusion, risk factors associated with colonisation/infection by isolates of A. baumannii with PHR to carbapenems are similar to those previously described for isolates resistant to carbapenems.

Community infections caused by extended-spectrum beta-lactamase-producing Escherichia coli.

BACKGROUND: Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli is an increasingly important group of community pathogens worldwide. These organisms are frequently resistant to many of the antimicrobial agents usually recommended for the treatment of infections caused by E coli, such as penicillins, cephalosporins, fluoroquinolones, and trimethoprim-sulfamethoxazole. Data concerning risk factors, clinical features, and therapeutic options for such infections are scarce. METHODS: A case-control study was performed to investigate the risk factors for all types of community-acquired infections caused by ESBL-producing E coli in 11 Spanish hospitals from February 2002 to May 2003. Controls were randomly chosen from among outpatients with a clinical sample not yielding ESBL-producing E coli. The clinical features of these infections were investigated in the case patients. The efficacy of fosfomycin tromethamine and amoxicillin-clavulanate potassium was observationally studied in patients with cystitis. RESULTS: A total of 122 cases were included. Risk factors selected by multivariate analysis included the following: age older than 60 years; female sex; diabetes mellitus; recurrent urinary tract infections (UTIs); previous invasive procedures of the urinary tract; follow-up in outpatient clinic; and previous receipt of aminopenicillins, cephalosporins, and fluoroquinolones. Urinary tract infections accounted for 93% of the cases; 6% of the patients were bacteremic and 10% needed hospitalization. The cure rate of patients with cystitis was 93% with fosfomycin therapy (all isolates were susceptible); among patients treated with amoxicillin-clavulanate, cure rates were 93% for those with susceptible isolates (minimum inhibitory concentration < or =8 microg/mL) and 56% for those with intermediate or resistant isolates (minimum inhibitory concentration > or =16 microg/mL) (P = .02). CONCLUSIONS: In predisposed patients, ESBL-producing E coli is a notable cause of community-acquired infection, and particularly UTI. Fosfomycin and amoxicillin-clavulanate appear to be effective for cystitis caused by susceptible isolates.

[Usefulness of the holmium:yag laser in the endoscopic section of ureteral stenosis]. / Utilidad del láser de holmium:yag en la sección endoscópica de la estenosis ureteral.

OBJECTIVES: The incidence of ureteral stenosis is frequent in our environment. Lately, due to the massive use of endourological techniques its incidence has increased. Etiology represents a decisive factor for the final result of treatment, but there are also common characteristics to all stenosis that influence very importantly the final success: time of evolution, length of the stenosis, side and function of the affected renal unit. Over the last years, the use of endourological techniques for the treatment of upper urinary tract stenosis, that substitute the traditional open technique, have increased. Holmium:YAG laser endoureterotomy presents advantages in comparison with other endourological techniques, because it enables a precise incision with direct vision of the ureteral stenosis. Moreover, with laser fibers ureteroscopes achieve a degree of flexibility/deflection that enables us to reach in most cases the stenotic area. At the time of incision of the ureteral wall, it should be complete, acting on all ureteral layers down to the periureteral fat, always having in mind the anatomic relationships of the ureter with neighbour structures, mainly vascular, to avoid injuries. Its effectiveness and easy management permits a high success rate, with resolution of the stenosis and a very low complication rate. After all the anterior, holmium laser retrograde endoureterotomy should be included as a first line treatment for benign ureteral stenosis.

[Retrograde laser endopyelotomy]. / Endopielotomía retrógrada con láser.

Ureteropyelic junction obstruction (UPJO) is the most frequent congenital anomaly of the upper urinary tract. Until some years ago, the treatment of first choice was open pyeloplasty, but the development of endoscopic surgery and the clinical improvement on instruments, enables the treatment in a minimally invasive fashion, offering the advantages of shorter operative time, less morbidity, reduction of post operative analgesic requirements, shorter hospital stay, and shorter convalescence period. Retrograde endopyelotomy represents the natural evolution of the minimally invasive surgical treatment of the UPJO by eliminating the need of a percutaneous renal tract and its possible complications. It may be performed in three ways: semirigid ureteroscope and electrocautery, cold knife or laser incision; flexible ureteroscope and electrocautery or laser incision; and under x-ray control with the Acucise cutting balloon catheter. Currently, the development of smaller ureterorenoscopes (semirigid and flexible) and the use of safer and more effective energy sources, such as holmium:YAG laser, have improved the results of this technique. We present the technique step-by-step and a bibliographic review.

[Lower calyx lithiasis: usefulness of the laser]. / Litiasis en cáliz inferior: utilidad del láser.

There is controversy yet about which is the best treatment modality for lithiasis of the lower calyx. The range of lithiasis clearance of the stones localized in the lower calyx will depend on various factors such as size, composition of the stone, type of lithotripter employed, type of urinary transport, and anatomy of the lower calyx. The role of flexible ureteroscopy in the treatment of intrarenal pathology has experimented a dramatic evolution, impulsed by the improvements in design of flexible ureterscopes, their degree of deflection, and better quality of image, in the great diversification of small calibre accessory instruments, and the use of the holmium laser for lithotripsy. Its development makes possible to offer it as a therapeutic option for the failures of extracorporeal lithotripsy in stones smaller than 1 cm and as first-line treatment for stones smaller than 1 cm in size if they are cystine stones or they have an attenuation level over 1000 HU; also in obese patients or those with coagulation problems.