Rodrigo Guzman Rojas

Characterization and pathogenicity of Vibrio splendidus strains associated with massive mortalities of commercial hatchery-reared larvae of scallop Argopecten purpuratus (Lamarck, 1819)

Three strains (VPAP16, VPAP18 and VPAP23 strains) were isolated as the most predominant organisms from 3 different episodes of massive mortalities of larval cultures of the Chilean scallop Argopecten purpuratus occurred in different commercial hatcheries located in northern Chile. The main aims of this study were to identify the pathogenic strains and investigate their pathogenic activity. Based on selected phenotypic features and sequence identity of the 16S rRNA gene and the housekeeping gene, RNA polymerase α-chain rpoA, all pathogenic strains were identified as Vibrio splendidus. Healthy 10-day-old scallop larvae cultures exhibited mortality percentages of 69.61±3.35%, 79.78±6.11% and 61.73±3.71% after 48 h when were inoculated with 1×10(6) CFU (colony forming units)mL(-1) of VPAP16, VPAP18 and VPAP23 strains, respectively, and evidenced that concentrations ⩾10(4) CFU mL(-1) would probably be detrimental for the larval culture. The main clinical signs observed in challenged larvae for 24h were bacterial swarms on the margins of the larvae, extension and disruption of the velum, detachment of velum cilia cells and digestive tissue necrosis. Otherwise, challenge assays using pathogenic strains stained with 5-([4,6-dichlorotriazin-2-yl]amino)fluorescein hydrochloride (5-DTAF)evidenced that after 1h stained bacteria were detected in high density in the digestive gland and the margin of the shell. When larval cultures were inoculated with cell-free extracellular products (ECP) of V. splendidus strains, exhibited larval mortalities higher than 70% (VPAP16), 80% (VPAP18) and 50% (VPAP23) after 24 h, even when ECP were treated with proteinase K or heat, indicating that extracellular pathogenic activity is mainly mediated by non-proteic thermostable compounds. In this study all Kochs postulates were fulfilled and it was demonstrated for the first time the pathogenic activity of V. splendidus strains on reared-larvae of scallop A. purpuratus and prompt the necessity to maintain this species at concentrations lower than 10(4) CFU mL(-1) to avoid episodes of mass mortalities in scallop hatcheries.

Postprocessing of pelvic floor ultrasound data: How repeatable is it?

Translabial 3D/4D pelvic floor ultrasound (PFUS) is increasingly used in the evaluation of pelvic floor disorders. Commonly, this involves the analysis of stored volume data sets by postprocessing. In this study, we aimed to assess the time requirement to reaching acceptable repeatability for commonly employed outcome measures in PFUS.

Urinary incontinence: the role of menopause.

ObjectiveThis study aims to explore the effects of menopause and hormone therapy on the symptoms and signs of stress urinary incontinence and urge urinary incontinence. MethodsRecords of women who attended a tertiary urogynecological unit were reviewed retrospectively. A standardized interview included evaluations of symptoms, menopause age (ie, time since last menstrual period or onset of menopausal symptoms), current or previous hormone use, and visual analogue scales for bother. Multichannel urodynamics, including urethral pressure profilometry and determination of abdominal leak point pressure, was performed. ResultsOf 382 women seen during the inclusion period, 62% were postmenopausal. Current systemic or local hormone use was reported by 7% and 6%, respectively. Two hundred eighty-eight women (76%) reported symptoms of stress urinary incontinence, with a mean bother of 5.7, and 273 women (72%) reported symptoms of urge urinary incontinence, with a mean bother of 6.4. On univariate analysis, symptoms and bother of urge incontinence were significantly related to menopause age, whereas this relationship was not found for stress incontinence. After calendar age was controlled for, length of menopause showed no significant relationship with any symptom or sign of urinary incontinence. ConclusionsHormone deficiency after menopause is unlikely to play a major role in urinary incontinence.

Role of shellfish hatchery as a reservoir of antimicrobial resistant bacteria.

The main aim of this study was to determine the occurrence of resistant bacteria in florfenicol-treated and untreated scallop larval cultures from a commercial hatchery and to characterize some selected florfenicol-resistant strains. Larval cultures from untreated and treated rearing tanks exhibited percentages of copiotrophic bacteria resistant to florfenicol ranging from 0.03% to 10.67% and 0.49-18.34%, respectively, whereas florfenicol resistance among oligotrophic bacteria varied from 1.44% to 35.50% and 3.62-95.71%, from untreated and treated larvae, respectively. Florfenicol resistant microbiota from reared scallop larvae mainly belonged to the Pseudomonas and Pseudoalteromonas genus and were mainly resistant to florfenicol, chloramphenicol, streptomycin and co-trimoxazole. This is the first study reporting antimicrobial resistant bacteria associated to a shellfish hatchery and the results suggest that a continuous surveillance of antimicrobial resistance even in absence of antibacterial therapy is urgently required to evaluate potential undesirable consequences on the surrounding environments.

Intrapartum predictors of maternal levator ani injury

Damage to the pelvic floor during vaginal childbirth is common, and may take the form of levator avulsion or irreversible overdistension of the levator hiatus (microtrauma). Such trauma is a major risk factor for pelvic organ prolapse later in life. In this study we aimed to identify intrapartum risk factors for levator trauma.

Defect-specific rectocele repair: Medium-term anatomical, functional and subjective outcomes

Rectocele is a herniation of the anterior wall of the rectal ampulla through a defect in the rectovaginal septum causing protrusion of the posterior vaginal wall. Common symptoms include symptoms of prolapse and obstructed defecation.

Antimicrobial Susceptibility of Flavobacterium psychrophilum from Chilean Salmon Farms and Their Epidemiological Cut-Off Values Using Agar Dilution and Disk Diffusion Methods

Flavobacterium psychrophilum is the most important bacterial pathogen for freshwater farmed salmonids in Chile. The aims of this study were to determine the susceptibility to antimicrobials used in fish farming of Chilean isolates and to calculate their epidemiological cut-off (COWT) values. A number of 125 Chilean isolates of F. psychrophilum were isolated from reared salmonids presenting clinical symptoms indicative of flavobacteriosis and their identities were confirmed by 16S rRNA polymerase chain reaction. Susceptibility to antibacterials was tested on diluted Mueller-Hinton by using an agar dilution MIC method and a disk diffusion method. The COWT values calculated by Normalized Resistance Interpretation (NRI) analysis allow isolates to be categorized either as wild-type fully susceptible (WT) or as manifesting reduced susceptibility (NWT). When MIC data was used, NRI analysis calculated a COWT of ≤0.125, ≤2, and ≤0.5 μg mL-1 for amoxicillin, florfenicol, and oxytetracycline, respectively. For the quinolones, the COWT were ≤1, ≤0.5, and ≤0.125 μg mL-1 for oxolinic acid, flumequine, and enrofloxacin, respectively. The disk diffusion data sets obtained in this work were extremely diverse and were spread over a wide range. For the quinolones there was a close agreement between the frequencies of NWT isolates calculated using MIC and disk data. For oxolinic acid, flumequine, and enrofloxacin the frequencies were 45, 39, and 38% using MIC data, and 42, 41, and 44%, when disk data were used. There was less agreement with the other antimicrobials, because NWT frequencies obtained using MIC and disk data, respectively, were 24 and 10% for amoxicillin, 8 and 2% for florfenicol, and 70 and 64% for oxytetracycline. Considering that the MIC data was more precise than the disk diffusion data, MIC determination would be the preferred method for susceptibility testing for this species and the NWT frequencies derived from the MIC data sets should be considered as the more authoritative. Despite the high frequency of isolates showing full susceptibility to florfenicol, the significant frequencies of isolates exhibiting reduced susceptibility to oxytetracycline and quinolones may result in treatment failures when these agents are used.

Does it matter whether avulsion is diagnosed pre‐ or postoperatively?

Levator ani muscle avulsion is found in 15–30% of parturients and is associated with recurrence of pelvic organ prolapse (POP) following surgery, although most published evidence on recurrence relates to postoperative diagnosis. We performed a study to determine whether a diagnosis of avulsion after pelvic floor surgery can be used as a proxy for preoperative diagnosis.

First Report of Vibrio tubiashii Associated with a Massive Larval Mortality Event in a Commercial Hatchery of Scallop Argopecten purpuratus in Chile

The VPAP30 strain was isolated as the highly predominant bacteria from an episode of massive larval mortality occurring in a commercial culture of the Chilean scallop Argopecten purpuratus. The main aims of this study were, to characterize and identify the pathogenic strain using biochemical and molecular methods to demonstrate its pathogenic activity on scallop larvae, to characterize its pathogenic properties and to describe the chronology of this pathology. The pathogenic strain was identified as Vibrio tubiashii based on its phenotypic properties and the sequence analysis of its 16S rRNA and housekeeping genes (ftsZ, gapA, gyrB, mreB, pyrH, recA, rpoA and topA). When triplicate cultures of healthy 10–day–old scallop larvae were challenged with 1 × 105 colony forming units (CFU) mL-1 of the VPAP30 strain, percentages of larval survival of 78.87 ± 3.33%, 34.32 ± 4.94%, and 0% were observed at 12, 24, and 36 h, respectively; whereas uninfected larval cultures showed survival rates of 97.4 ± 1.24% after of 48 h. Clinical symptoms exhibited by the scallop larvae infected with the VPAP30 strain include the accumulation of bacteria around the scallop larvae, velum disruption and necrosis of digestive gland. The 50% lethal dose (LD50) of VPAP30 strain at 24 and 48 h was 1.3 × 104 and 1.2 × 103 CFU mL-1, respectively. The invasive pathogenic activity of the VPAP30 strain was investigated with staining of the bacterial pathogen with 5-DTAF and analyzing bacterial invasion using epifluorescence, and a complete bacterial dissemination inside the larvae at 24 h post-infection was observed. When scallop larvae were inoculated with cell-free extracellular products (ECPs) of VPAP30, the larval survival rate was 59.5 ± 1.66%, significantly (P < 0.001) lower than the control group (97.4 ± 1.20%) whereas larvae treated with heat-treated ECPs exhibited a survival rate of 61.6 ± 1.84% after 48 h of exposure. This is the first report of the isolation of V. tubiashii from the diseased larvae of the scallop A. purpuratus, occurring in a commercial culture in Chile, and it was demonstrated that the VPAP30 strain exhibits high pathogenic activity on scallop larvae, mediated both by bacterial invasion and the production of toxigenic heat-stable compounds.

Obesity: how much does it matter for female pelvic organ prolapse?

Introduction and hypothesisThe objective was to determine the association between body mass index (BMI) and symptoms and signs of female pelvic organ prolapse (POP).MethodsAn observational cross-sectional study of 964 archived datasets of women seen for symptoms and signs of lower urinary tract and pelvic organ dysfunction between September 2011 and February 2014 at a tertiary urogynaecology centre in Australia was carried out. An in-house standardised interview, the International Continence Society Pelvic Organ Prolapse Quantification (ICS POP-Q) and 4-D translabial ultrasound, followed by analysis of ultrasound volumes for pelvic organ descent and hiatal area on Valsalva, were performed, blinded against other data.ResultsThere is a positive association between BMI and posterior compartment prolapse on clinical examination and ultrasound imaging, but not for the anterior and central compartments. There was no association with prolapse symptom bother and a negative association with symptoms of prolapse.ConclusionsIn this observational study, we found a strong association between all tested measures of posterior compartment descent and BMI, both clinical and on imaging.