Reef manta rays forage on tidally driven, high density zooplankton patches in Hanifaru Bay, Maldives.

Manta rays forage for zooplankton in tropical and subtropical marine environments, which are generally nutrient-poor. Feeding often occurs at predictable locations where these large, mobile cartilaginous fishes congregate to exploit ephemeral productivity hotspots. Investigating the zooplankton dynamics that lead to such feeding aggregations remains a key question for understanding their movement ecology. The aim of this study is to investigate the feeding environment at the largest known aggregation for reef manta rays Mobula alfredi in the world. We sampled zooplankton throughout the tidal cycle, and recorded M. alfredi activity and behaviour, alongside environmental variables at Hanifaru Bay, Maldives. We constructed generalised linear models to investigate possible relationships between zooplankton dynamics, environmental parameters, and how they influenced M. alfredi abundance, behaviour, and foraging strategies. Zooplankton biomass changed rapidly throughout the tidal cycle, and M. alfredi feeding events were significantly related to high zooplankton biomass. Mobula alfredi switched from non-feeding to feeding behaviour at a prey density threshold of 53.7 mg dry mass m-3; more than double the calculated density estimates needed to theoretically meet their metabolic requirements. The highest numbers of M. alfredi observed in Hanifaru Bay corresponded to when they were engaged in feeding behaviour. The community composition of zooplankton was different when M. alfredi was feeding (dominated by copepods and crustaceans) compared to when present but not feeding (more gelatinous species present than in feeding samples). The dominant zooplankton species recorded was Undinula vulgaris. This is a large-bodied calanoid copepod species that blooms in oceanic waters, suggesting offshore influences at the site. Here, we have characterised aspects of the feeding environment for M. alfredi in Hanifaru Bay and identified some of the conditions that may result in large aggregations of this threatened planktivore, and this information can help inform management of this economically important marine protected area.

A database of zooplankton biomass in Australian marine waters.

Zooplankton biomass data have been collected in Australian waters since the 1930s, yet most datasets have been unavailable to the research community. We have searched archives, scanned the primary and grey literature, and contacted researchers, to collate 49187 records of marine zooplankton biomass from waters around Australia (0-60°S, 110-160°E). Many of these datasets are relatively small, but when combined, they provide >85 years of zooplankton biomass data for Australian waters from 1932 to the present. Data have been standardised and all available metadata included. We have lodged this dataset with the Australian Ocean Data Network, allowing full public access. The Australian Zooplankton Biomass Database will be valuable for global change studies, research assessing trophic linkages, and for initialising and assessing biogeochemical and ecosystem models of lower trophic levels.

Wolff Parkinson white pattern in Danon disease: When preexcitation is not what it seems.

Danondisease is a rare genetic disorder with an X-linked dominant inheritance affecting both skeletal and cardiac muscle. Its characteristic cardiac phenotype consists on a severe, non-obstructive and concentric hypertrophic cardiomyopathy (HCM) usually associated with a Wolff-Parkinson-White (WPW) type preexcitation pattern. Whether this corresponds to the presence of an AV or another type of accessory pathways, such as fasciculoventricular pathways (FVP) remains controversial in the literature. However, we describe the case of a teenager with Danon disease and preexcitation who develops a first degree AV block without any change in his QRS morphology, fact that favors the hypothesis of the presence of a FVP. This finding has important clinical implications in the management and prognosis of these complex patients. The absence of an AV accessory pathway decreases their risk of potential SCD in the context of a fast atrial arrhythmia and their chances of having a reentrant AV tachycardia.

Two new species of Hydromedusae from Queensland, Australia (Hydrozoa, Leptothecata).

Two new species of small hydromedusae were found during routine monitoring in coastal waters of eastern Australia and are here described. The first, Melicertissaantrichardsoni Uribe-Palomino & Gershwin, sp. n., from Moreton Bay, Queensland, is placed in its genus because of its possession of both cordyli and eight-fold symmetry. It differs from its congeners in two conspicuous features: firstly, having small, oval split gonads located adjacent to the base of the stomach, and secondly, in its extremely small size at maturity (2 mm bell diameter, compared to the next smallest species at 7 mm). Moreover, it possesses a unique combination of other characters. This species appears to be endemic to Moreton Bay. The second new species, Paraloveniayongalensis Gershwin & Uribe-Palomino, sp. n., from the Great Barrier Reef, Queensland, is placed in its genus because of its two opposite normal tentacles and two opposite marginal clusters of cirri. It differs from its congeners primarily in a more rounded body than the others; the shape, length, and position of its short spindle-shaped, distal gonads; possession of subumbrellar nematocyst clusters; and possession of statocysts. These discoveries bring the total number of Melicertissa species to eight and the total number of Paralovenia species to three. The discovery of these two micromedusae underscores the need for further examination of the often-ignored minute and/or gelatinous fauna.

A database of chlorophyll a in Australian waters.

Chlorophyll a is the most commonly used indicator of phytoplankton biomass in the marine environment. It is relatively simple and cost effective to measure when compared to phytoplankton abundance and is thus routinely included in many surveys. Here we collate 173, 333 records of chlorophyll a collected since 1965 from Australian waters gathered from researchers on regular coastal monitoring surveys and ocean voyages into a single repository. This dataset includes the chlorophyll a values as measured from samples analysed using spectrophotometry, fluorometry and high performance liquid chromatography (HPLC). The Australian Chlorophyll a database is freely available through the Australian Ocean Data Network portal (https://portal.aodn.org.au/). These data can be used in isolation as an index of phytoplankton biomass or in combination with other data to provide insight into water quality, ecosystem state, and relationships with other trophic levels such as zooplankton or fish.

Long-Term Impact of an Educational Antimicrobial Stewardship Program on Hospital-Acquired Candidemia and Multidrug-Resistant Bloodstream Infections: A Quasi-Experimental Study of Interrupted Time-Series Analysis.

BACKGROUND: The global crisis of bacterial resistance urges the scientific community to implement intervention programs in healthcare facilities to promote an appropriate use of antibiotics. However, the clinical benefits or the impact on resistance of these interventions has not been definitively proved. METHODS: We designed a quasi-experimental intervention study with an interrupted time-series analysis. A multidisciplinary team conducted a multifaceted educational intervention in our tertiary-care hospital over a 5-year period. The main activity of the program consisted of peer-to-peer educational interviews between counselors and prescribers from all departments to reinforce the principles of the proper use of antibiotics. We assessed antibiotic consumption, incidence density of Candida and multidrug-resistant (MDR) bacteria bloodstream infections (BSIs) and their crude death rate per 1000 occupied bed days (OBDs). RESULTS: A quick and intense reduction in antibiotic consumption occurred 6 months after the implementation of the intervention (change in level, -216.8 defined daily doses per 1000 OBDs; 95% confidence interval, -347.5 to -86.1), and was sustained during subsequent years (average reduction, -19,9%). In addition, the increasing trend observed in the preintervention period for the incidence density of candidemia and MDR BSI (+0.018 cases per 1000 OBDs per quarter; 95% confidence interval, -.003 to .039) reverted toward a decreasing trend of -0.130 per quarter (change in slope, -0.029; -.051 to -.008), and so did the mortality rate (change in slope, -0.015; -.021 to -.008). CONCLUSIONS: This education-based antimicrobial stewardship program was effective in decreasing the incidence and mortality rate of hospital-acquired candidemia and MDR BSI through sustained reduction in antibiotic use.

The Not-So-Good Prognosis of Streptococcal Periprosthetic Joint Infection Managed by Implant Retention: The Results of a Large Multicenter Study.

BACKGROUND.: Streptococci are not an infrequent cause of periprosthetic joint infection (PJI). Management by debridement, antibiotics, and implant retention (DAIR) is thought to produce a good prognosis, but little is known about the real likelihood of success. METHODS.: A retrospective, observational, multicenter, international study was performed during 2003-2012. Eligible patients had a streptococcal PJI that was managed with DAIR. The primary endpoint was failure, defined as death related to infection, relapse/persistence of infection, or the need for salvage therapy. RESULTS.: Overall, 462 cases were included (median age 72 years, 50% men). The most frequent species was Streptococcus agalactiae (34%), and 52% of all cases were hematogenous. Antibiotic treatment was primarily using ß-lactams, and 37% of patients received rifampin. Outcomes were evaluable in 444 patients: failure occurred in 187 (42.1%; 95% confidence interval, 37.5%-46.7%) after a median of 62 days from debridement; patients without failure were followed up for a median of 802 days. Independent predictors (hazard ratios) of failure were rheumatoid arthritis (2.36), late post-surgical infection (2.20), and bacteremia (1.69). Independent predictors of success were exchange of removable components (0.60), early use of rifampin (0.98 per day of treatment within the first 30 days), and long treatments (≥21 days) with ß-lactams, either as monotherapy (0.48) or in combination with rifampin (0.34). CONCLUSIONS.: This is the largest series to our knowledge of streptococcal PJI managed by DAIR, showing a worse prognosis than previously reported. The beneficial effects of exchanging the removable components and of ß-lactams are confirmed and maybe also a potential benefit from adding rifampin.

Executive summary of management of prosthetic joint infections. Clinical practice guidelines by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) / Resumen ejecutivo de tratamiento de las infecciones de prótesis articulares. Guia clínica práctica de la Sociedad Española de Enfermedades Infecciosas y Microbiologia Clínica

The incidence of prosthetic joint infection (PJI) is expected to increase in the coming years. PJI has serious consequences for patients, and high costs for the health system. The complexity of these infections makes it necessary to organize the vast quantity of information published in the last several years. The indications for the choice of a given surgical strategy and the corresponding antimicrobial therapy are specifically reviewed. The authors selected clinically relevant questions and then reviewed the available literature in order to give recommendations according to a pre-determined level of scientific evidence. The more controversial aspects were debated, and the final composition was agreed at an ad hoc meeting. Before its final publication, the manuscript was made available online in order that all SEIMC members were able to read it and make comments and suggestions

Se prevé un incremento de la incidencia de infección de las prótesis articulares (IPA) en los próximos años. Las IPA plantean graves consecuencias para los pacientes y un alto coste el sistema sanitario. La complejidad de estas infecciones hace que sea necesario organizar la inmensa cantidad de información publicada en los últimos años. En estas guías se revisan específicamente las indicaciones para la elección de una estrategia quirúrgica dada y el tratamiento antimicrobiano correspondiente. Los autores seleccionaron las preguntas clínicamente relevantes y revisaron la literatura disponible con el fin de proporcionar recomendaciones de acuerdo con un grado de evidencia científica predeterminada. Los aspectos más controvertidos fueron debatidos y la redacción final se acordó en una reunión ad hoc. Antes de su publicación, el manuscrito estuvo abierto a comentarios y sugerencias de los miembros de la Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica

Executive summary of management of prosthetic joint infections. Clinical practice guidelines by the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC).

The incidence of prosthetic joint infection (PJI) is expected to increase in the coming years. PJI has serious consequences for patients, and high costs for the health system. The complexity of these infections makes it necessary to organize the vast quantity of information published in the last several years. The indications for the choice of a given surgical strategy and the corresponding antimicrobial therapy are specifically reviewed. The authors selected clinically relevant questions and then reviewed the available literature in order to give recommendations according to a pre-determined level of scientific evidence. The more controversial aspects were debated, and the final composition was agreed at an ad hoc meeting. Before its final publication, the manuscript was made available online in order that all SEIMC members were able to read it and make comments and suggestions.

Truncating FLNC Mutations Are Associated With High-Risk Dilated and Arrhythmogenic Cardiomyopathies.

BACKGROUND: Filamin C (encoded by the FLNC gene) is essential for sarcomere attachment to the plasmatic membrane. FLNC mutations have been associated with myofibrillar myopathies, and cardiac involvement has been reported in some carriers. Accordingly, since 2012, the authors have included FLNC in the genetic screening of patients with inherited cardiomyopathies and sudden death. OBJECTIVES: The aim of this study was to demonstrate the association between truncating mutations in FLNC and the development of high-risk dilated and arrhythmogenic cardiomyopathies. METHODS: FLNC was studied using next-generation sequencing in 2,877 patients with inherited cardiovascular diseases. A characteristic phenotype was identified in probands with truncating mutations in FLNC. Clinical and genetic evaluation of 28 affected families was performed. Localization of filamin C in cardiac tissue was analyzed in patients with truncating FLNC mutations using immunohistochemistry. RESULTS: Twenty-three truncating mutations were identified in 28 probands previously diagnosed with dilated, arrhythmogenic, or restrictive cardiomyopathies. Truncating FLNC mutations were absent in patients with other phenotypes, including 1,078 patients with hypertrophic cardiomyopathy. Fifty-four mutation carriers were identified among 121 screened relatives. The phenotype consisted of left ventricular dilation (68%), systolic dysfunction (46%), and myocardial fibrosis (67%); inferolateral negative T waves and low QRS voltages on electrocardiography (33%); ventricular arrhythmias (82%); and frequent sudden cardiac death (40 cases in 21 of 28 families). Clinical skeletal myopathy was not observed. Penetrance was >97% in carriers older than 40 years. Truncating mutations in FLNC cosegregated with this phenotype with a dominant inheritance pattern (combined logarithm of the odds score: 9.5). Immunohistochemical staining of myocardial tissue showed no abnormal filamin C aggregates in patients with truncating FLNC mutations. CONCLUSIONS: Truncating mutations in FLNC caused an overlapping phenotype of dilated and left-dominant arrhythmogenic cardiomyopathies complicated by frequent premature sudden death. Prompt implantation of a cardiac defibrillator should be considered in affected patients harboring truncating mutations in FLNC.

Short- versus long-duration levofloxacin plus rifampicin for acute staphylococcal prosthetic joint infection managed with implant retention: a randomised clinical trial.

Levofloxacin plus rifampicin (L+R) is the treatment of choice for acute staphylococcal prosthetic joint infection (PJI) managed with debridement and implant retention (DAIR). Long courses have been empirically recommended, but some studies have suggested that shorter treatments could be as effective. Our aim was to prove that a short treatment schedule was non-inferior to the standard long schedule. An open-label, multicentre, randomised clinical trial (RCT) was performed. Patients with an early post-surgical or haematogenous staphylococcal PJI, managed with DAIR and initiated on L+R were randomised to receive 8 weeks of treatment (short schedule) versus a long schedule (3 months or 6 months for hip or knee prostheses, respectively). The primary endpoint was cure rate. From 175 eligible patients, 63 were included (52% women; median age, 72 years): 33 patients (52%) received the long schedule and 30 (48%) received the short schedule. There were no differences between the two groups except for a higher rate of polymicrobial infection in the long-schedule group (27% vs. 7%; P = 0.031). Median follow-up was 540 days. In the intention-to-treat analysis, cure rates were 58% and 73% in patients receiving the long and short schedules, respectively (difference -15.7%, 95% CI -39.2% to 7.8%). Forty-four patients (70%) were evaluable per-protocol: cure rates were 95.0% and 91.7% for the long and short schedules, respectively (difference 3.3%, 95% CI -11.7% to 18.3%). This is the first RCT suggesting that 8 weeks of L+R could be non-inferior to longer standard treatments for acute staphylococcal PJI managed with DAIR.

A database of marine phytoplankton abundance, biomass and species composition in Australian waters.

There have been many individual phytoplankton datasets collected across Australia since the mid 1900s, but most are unavailable to the research community. We have searched archives, contacted researchers, and scanned the primary and grey literature to collate 3,621,847 records of marine phytoplankton species from Australian waters from 1844 to the present. Many of these are small datasets collected for local questions, but combined they provide over 170 years of data on phytoplankton communities in Australian waters. Units and taxonomy have been standardised, obviously erroneous data removed, and all metadata included. We have lodged this dataset with the Australian Ocean Data Network (http://portal.aodn.org.au/) allowing public access. The Australian Phytoplankton Database will be invaluable for global change studies, as it allows analysis of ecological indicators of climate change and eutrophication (e.g., changes in distribution; diatom:dinoflagellate ratios). In addition, the standardised conversion of abundance records to biomass provides modellers with quantifiable data to initialise and validate ecosystem models of lower marine trophic levels.

Prey Density Threshold and Tidal Influence on Reef Manta Ray Foraging at an Aggregation Site on the Great Barrier Reef.

Large tropical and sub-tropical marine animals must meet their energetic requirements in a largely oligotrophic environment. Many planktivorous elasmobranchs, whose thermal ecologies prevent foraging in nutrient-rich polar waters, aggregate seasonally at predictable locations throughout tropical oceans where they are observed feeding. Here we investigate the foraging and oceanographic environment around Lady Elliot Island, a known aggregation site for reef manta rays Manta alfredi in the southern Great Barrier Reef. The foraging behaviour of reef manta rays was analysed in relation to zooplankton populations and local oceanography, and compared to long-term sighting records of reef manta rays from the dive operator on the island. Reef manta rays fed at Lady Elliot Island when zooplankton biomass and abundance were significantly higher than other times. The critical prey density threshold that triggered feeding was 11.2 mg m-3 while zooplankton size had no significant effect on feeding. The community composition and size structure of the zooplankton was similar when reef manta rays were feeding or not, with only the density of zooplankton changing. Higher zooplankton biomass was observed prior to low tide, and long-term (~5 years) sighting data confirmed that more reef manta rays are also observed feeding during this tidal phase than other times. This is the first study to examine prey availability at an aggregation site for reef manta rays and it indicates that they feed in locations and at times of higher zooplankton biomass.

Linezolid in late-chronic prosthetic joint infection caused by gram-positive bacteria.

Linezolid may be an interesting alternative for prosthetic joint infection (PJI) due to its bioavailability and its antimicrobial spectrum. However, experience in this setting is scarce. The aim of the study was to assess linezolid's clinical and microbiological efficacy, and also its tolerance. This was a prospective, multicenter, open-label, non-comparative study of 25 patients with late-chronic PJI caused by Gram-positive bacteria managed with a two-step exchange procedure plus 6 weeks of linezolid. Twenty-two (88%) patients tolerated linezolid without major adverse effects, although a global decrease in the platelet count was observed. Three patients were withdrawn because of major toxicity, which reversed after linezolid stoppage. Among patients who completed treatment, 19 (86%) demonstrated clinical and microbiological cure. Two patients presented with clinical and microbiological failure, and one showed clinical cure and microbiological failure. In conclusion, linezolid showed good results in chronic PJI managed with a two-step exchange procedure. Tolerance seems acceptable, though close surveillance is required.

A large multicenter study of methicillin-susceptible and methicillin-resistant Staphylococcus aureus prosthetic joint infections managed with implant retention.

BACKGROUND: Several series predicting the prognosis of staphylococcal prosthetic joint infection (PJI) managed with debridement, antibiotics, and implant retention (DAIR) have been published, but some of their conclusions are controversial. At present, little is known regarding the efficacy of the different antibiotics that are used or their ability to eliminate methicillin-resistant S. aureus (MRSA) infection. METHODS: This was a retrospective, multicenter, observational study of cases of PJI by S. aureus that were managed with DAIR (2003-2010). Cases were classified as failures when infection persistence/relapse, death, need for salvage therapy, or prosthesis removal occurred. The parameters that predicted failure were analyzed with logistic and Cox regression. RESULTS: Out of 345 episodes (41% men, 73 years), 81 episodes were caused by MRSA. Fifty-two were hematogenous, with poorer prognoses, and 88% were caused by methicillin-susceptible S. aureus (MSSA). Antibiotics were used for a median of 93 days, with similar use of rifampin-based combinations in MSSA- and MRSA-PJI. Failure occurred in 45% of episodes, often early after debridement. The median survival time was 1257 days. There were no overall prognostic differences between MSSA- and MRSA-PJI, but there was a higher incidence of MRSA-PJI treatment failure during the period of treatment (HR 2.34), while there was a higher incidence of MSSA-PJI treatment failure after therapy. Rifampin-based combinations exhibited an independent protective effect. Other independent predictors of outcome were polymicrobial, inflammatory, and bacteremic infections requiring more than 1 debridement, immunosuppressive therapy, and the exchange of removable components of the prosthesis. CONCLUSIONS: This is the largest series of PJI by S. aureus managed with DAIR reported to date. The success rate was 55%. The use of rifampin may have contributed to homogenizing MSSA and MRSA prognoses, although the specific rifampin combinations may have had different efficacies.

[Aminoglycosides and polymyxins]. / Aminoglucósidos y polimixinas.

The emergence of multidrug-resistant strains of gram-negative bacilli during the last decade has generated renewed interest in older antimicrobials that had been relegated to a second line because of a poorer safety profile, but that are still active against these microorganisms. Once-daily administration of aminoglycosides has limited the toxicity of these agents and enabled their reintroduction into clinical practice. Recent studies have shown no additional benefits of concomitant administration of aminoglycosides with current ss-lactams, and the available evidence does not support the use of once-daily administration for all indications. The new formulations and dosages of polymyxins have also reduced the toxicity rates attributed to these agents in the past. Although more extensive studies are required to properly define their pharmacokinetics and effectiveness, the available data have shown favorable outcomes for patients with infection due to multiresistant gram-negative bacilli treated with colistin, either alone or combined with other antimicrobial agents.

Aminoglucosidos y polimixinas / Aminoglycosides and polymyxins

En la última década, la expansión de cepas de bacilos gramnegativos multirresistentes ha suscitado un nuevo interés por antimicrobianos hasta ahora relegados a un segundo plano por un peor perfil de seguridad, pero que aún conservaban su actividad frente a estos microorganismos.La administración de aminoglucósidos en monodosis ha permitido minimizar sus efectos tóxicos y reintroducirlos en la práctica clínica. Por otra parte, estudios recientes han puesto en entredicho la utilidad de asociar aminoglucósidos a los (..) (AU)

The emergence of multidrug-resistant strains of gram-negative bacilli during the last decade has generated renewed interest in older antimicrobials that had been relegated to a second line because of a poorer safety profile, but that are still active against these microorganisms. Once-daily administration of aminoglycosides has limited the toxicity of these agents and enabled their reintroduction into clinical practice. Recent studies have shown no additional benefits of concomitant administration of aminoglycosides with current (..) AU)

[Aminoglycosides]. / Aminoglucósidos.

Aminoglycosides remain as a efficacious class of antimicrobials, commonly used in the clinical practice. In spite of the existence of several mechanisms of resistance, they continue being active against most of the aerobic Gram-negative bacilli. Currently, although aminoglycosides may be used as monotherapy in the urinary tract infections, they are mainly used in combination with b-lactam antibiotics in severe infections caused by Gram-negative bacilli. The knowledge about the pharmacokinetic and pharmacodynamic parameters of aminoglycosides has suggested their use in an once-daily dosing regimen. This dosing has shown as efficacious as multiple-daily dosing regimen in several studies, which also have shown a trend toward a lower toxicity. Among the adverse events, nephrotoxicity and ototoxicity require a careful evaluation during its administration.