Buenos Aires Province Research Articles

Molecular detection of reproductive symbionts and parthenogenesis experiments in Tuta absoluta from Argentina: facing potential for sustainable and specific pest control strategies

AbstractTomato leafminer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a key pest of tomato crops. Specific and environmentally friendly control strategies against this pest, such as the sterile insect technique (SIT), are under development and sexual reproduction has emerged as a key focal point to ensure its success. In the present study, we analyzed four representative T. absoluta populations from Argentina, focusing on the molecular detection of endosymbionts potentially associated with reproductive abnormalities and on determining whether parthenogenesis can occur under laboratory conditions. Larvae of T. absoluta were collected in commercial tomato plantations from La Plata and Mar del Plata (both in Buenos Aires province), Bella Vista (Corrientes province), and Yuto (Jujuy province). Tuta absoluta adults were evaluated by standard PCR for the presence of reproductive endosymbionts (Wolbachia sp., Spiroplasma sp., Arsenophonus sp., Cardinium sp., and Rickettsia sp.). For parthenogenesis assays, 20–23 virgin females from each T. absoluta geographic population were life‐long isolated in Petri dishes with a tomato leaf. Fecundity, fertility, and female longevity were estimated and compared with results from mated females from each population. Our results showed the presence of a unique endosymbiont (Wolbachia sp. supergroup B, sequence type 41). Fecundity of the unmated females was significantly lower than fecundity of mated females in all T. absoluta populations. In addition, unmated females only laid infertile eggs. In conclusion, the absence of parthenogenesis in T. absoluta from representative geographic populations supports the implementation of SIT and mating disruption as effective control strategies against this pest in Argentina.

Physicochemical Characterization Of Argentinian Honeys From The Phytogeographic Provinces Pampeana, Espinal And Monte Based On Their Sugar Profiles And Quality Parameters

The honeys from the Phytogeographic Provinces (PP) of the south of Buenos Aires province (Argentina) were characterised by the sugar composition and physicochemical parameters used for honey quality control. A large set (n=329) of traceable raw honey samples obtained from beekeepers were analysed and met the specifications of the national and/or international standards for the evaluated parameters, which denoted their blossom origin and confirmed their authenticity, good maturity and freshness. The influence of flora and the pedoclimatic conditions of each phytogeographical region, as well as their beekeeping practices, on the physical and chemical properties of honey allowed its characterization. Thus, the honeys from the southeast of Buenos Aires province were characterized by higher contents of moisture, fructose, maltose, erlose, hydroxymethylfurfural (HMF) and ash, pH and electrical conductivity (EC) and slightly lighter colours; while southwest honeys showed higher free acidities, sucrose content and ºBrix values. Honeys from the PP Espinal exhibited characteristic lower contents of fructose, HMF and ash and EC values, and larger amounts of sucrose. Honeys from the PP Monte presented typical lower moisture contents and slightly darker colours. Honeys from the PP Pampeana were typified by higher amounts of fructose.

Environmental drivers of long-term variations in the abundance of the red hocicudo mouse (Oxymycterus rufus) in Pampas agroecosystems.

During the 20th century, there has been an ongoing agricultural expansion and global warming, two of the main determinants influencing biodiversity changes in Argentina. The red hocicudo mouse (Oxymycterus rufus) inhabits subtropical grasslands and riparian habitats and has increased its abundance in recent years in central Argentina agroecosystems. This paper describes the long-term temporal changes in O. rufus abundance in Exaltación de la Cruz department, Buenos Aires province, Argentina, in relation to weather fluctuations and landscape features, as well as analyzes the spatio-temporal structure of captures of animals. We used generalized liner models, semivariograms, the Mantel test, and autocorrelation functions for the analysis of rodent data obtained from trappings conducted between 1984 and 2014. O. rufus showed an increase in abundance across the years of study, with its distribution depending on landscape features, such as habitat types and the distance to floodplains. Capture rates showed a spatio-temporal aggregation, suggesting expansion from previously occupied sites. O. rufus was more abundant at lower minimum temperatures in summer, higher precipitation in spring and summer, and lower precipitations in winter. Weather conditions affected O. rufus abundance, but there was local variation that differed from global patterns of climate change.

Maize (Zea Mays L.) Yield Estimation Using High Spatial and Temporal Resolution Sentinel-2 Remote Sensing Data

ABSTRACT Maize (Zea mays L.) is one of the world’s most important annual cereal crops and its yield can be estimated for a wide variety of purposes. The objective of this work is to evaluate in which stage of crop the best fit between remote sensing data and real yield occurs to predict yield in corn seed crops. For this, polynomial regression models were used between spectral indices of vegetation and real yield in 10 days time’s windows covering the critical period for generation of performance. Subsequently, the predictive capacity of the best goodness of fit model was evaluated by comparing estimates with those made using a conventional field estimation method. This experiment was carried out in production fields located in Tandil and Loberia district inside of the Argentine Pampas Region in southeast of Buenos Aires province in summer (from january to march) of 2020. We found the highest level of adjustment between vegetal index and real yield (R2 = 0.91) in the time window of 110 to 120 days after sowing (DAS) corresponding to the end of the critical period. Then, the predictive performance was evaluated, satellite model shows an underestimation of 53 kg/ha (0.72% relative error) while the conventional method underestimated by 955 kg/ha (13% relative error). A close relationship between remote sensing data and grain yield at the end of the critical period of maize can be evidenced, and this information can be used to predict yield early in the southeast of Buenos Aires province. Using the methodology here developed it is recommended to analyze- time series of satellite vegetal index in maize crops in other regions and climates to make more robust the yield prediction system.

Land uses in cities and their impacts on the water quality of urban freshwater blue spaces in the Pampean region (Argentina).

Freshwater blue spaces (FBS), such as ponds, are key elements of the urban landscape and are under strong anthropogenic pressure. Land-use types and diversity may exert a negative or positive impact on FBS' water quality depending on their nature and arrangement. The information available in this respect is remarkably scarcer for water bodies in the Global South than for the north. Thus, we aim to identify and quantify the land-use types in a 500-m buffer zone of urban ponds in the Pampean region (Argentina) to assess their impact on water quality. We based our study on 15 FBS located in neighborhoods of Buenos Aires province during cold and warm seasons. We analyzed physical, chemical, and biological variables, and estimated water conditions by means of water quality indexes (WQIs) and quality guidelines. We quantified the dominant land-use type and the diversity of uses in the ponds' buffer zones, and evaluated their relationships with WQIs. Our results showed that WQIs were negatively related to a high proportion of residential areas in the adjacent zone, while positively to recreational ones. The diversity of land uses did not influence the water quality. We propose a new WQIpond with fewer key response variables, and as sensitive as the currently used WQIobjetive. We conclude that water quality from urban ponds in the Pampean region can be affected by dominant land-use type in the adjacent area but also the quality of their water supply sources (superficial and/or underground), clandestine wastewater discharges, and non-point pollution.

Seroprevalence and risk factors for brucellosis and leptospirosis in swine from rural communities of Argentina

Objectives. To determine the seroprevalence of brucellosis and leptospirosis in pigs reared on small-scale farms in rural areas of the district of Tandil, Buenos Aires Province, Argentina; to analyse the associated risk factors; to describe the prevalent Leptospira spp. serogroups; and to determine the spatial distribution of both diseases. Materials and methods. A total of 340 serum samples were obtained. Buffer Plate Agglutination Test, Rose Bengal Test, and Fluorescence Polarisation Assay were used to detect antibodies against Brucella spp. Microscopic Agglutination Test was applied for serological diagnosis of leptospirosis. Statistical methods were used to evaluate the factors associated with the infections. Results. Seroprevalence of 0% and 22.6% was observed for brucellosis and leptospirosis, respectively. The most prevalent Leptospira serogroups identified were Canicola, Ballum, Icterohaemorrhagiae and Pomona. The main risk factors associated with leptospirosis infection were farms with a higher number of pigs and the presence of horses and wild boars near or within the farms. The use of milling by-products of cereal grains as animal feed and the presence of weaning cages were also associated. A relevant spatial cluster of seropositivity to Leptospira spp. was identified in a low-altitude area. Conclusions. Our results suggest that brucellosis is probably controlled, but Leptospira spp. are present in the farming systems under study. Knowledge of brucellosis and leptospirosis seroprevalence, spatial distribution and associated risk factors can be useful for the prevention and control of endemic zoonotic diseases in the region.

Meanings and practices about work of women discharged from a psychiatric hospital of Buenos Aires province, Argentina

Work is central to the social inclusion of people who have had long-term psychiatric hospitalizations. In the context of the mental health care reform in Argentina, it is important to produce local knowledge about work inclusion of people discharged from psychiatric hospitals. The objective of this study was to describe the meanings and practices of women who had long-term psychiatric hospitalizations at the José A. Estéves Hospital in the Province of Buenos Aires, Argentina, regarding their inclusion in the labor market, once they return to live in the community. Descriptive mixed-methods study. The case of the Assisted Discharge and Rehabilitation Program of José A. Estéves Hospital, which accompanied 69 women in the year 2018, was analyzed. For quantitative analysis the data of the 69 women was analyzed, and for qualitative analysis a sample of nine women were interviewed. 74% of women did some work after their discharge, although at the moment of the study only 33% were working. The jobs they carried out corresponded to elementary and low-competence occupational levels, mostly in a supported work program. After the psychiatric hospitalization, jobs obtained were less qualified, more informal and less exposed to the public than those held before the hospitalization. Prolonged psychiatric hospitalization is a significant break in people’s work trajectories. Despite the value of work experiences after having a psychiatric hospitalization, those experiences mainly correspond to the informal sector of the economy.

Survey on rheumatic disease symptom recognition by the general population

Introduction/ObjectivesTo assess people's level of recognition of rheumatic disease symptoms and their awareness that the rheumatologist is the main effector when it comes to these disorders. Materials and methodsSurvey performed in 8 towns in the Buenos Aires Province. Every town had at least one rheumatologist. Three clinical cases were presented: (1) inflammatory low back pain, (2) systemic disease, and (3) chronic polyarthritis. The population was asked whether (a) a physician should be immediately consulted, or (b) they could wait. They were asked whether they would advocate any initial treatment. They were also asked which physician should be consulted. ResultsOut of 150 surveys, 68% were female, the average age was 51.7 years old. Most people asserted that treatment with anti-inflammatory drugs should come first: 83% in inflammatory low back pain, 70% in systemic disease, and 70% in chronic polyarthritis (p=0.02). The number of men that suggested waiting was higher (47% vs. 28% of women; p=0.04). A rheumatologist was recommended by 51% for chronic polyarthritis, 15% for systemic disease, and 8% for inflammatory low back pain (p<0.0001). Thirty-eight percent of those who never considered consulting a rheumatologist had elementary education vs. 19% of those who considered consulting a rheumatologist for one of the 3 cases (p=0.01) ConclusionsChronic polyarthritis was the disease people identified best as within the rheumatologist's field of expertise. Men tended to delay consultation more than women. Consultation is less likely when the level of education is lower.

Comunidades de aves en barrios residenciales y en bosques implantados en médanos costeros de la localidad de Cariló, Argentina

Coastal areas have the largest human population, causing significant urbanization impacts on biodiversity. The coast of Buenos Aires province (Argentina) has touristic cities, which have shown significant growth during the last decades. Therefore, it is fundamental to analyze the effect of urbanization on bird communities. The aim of this study is to analyze the bird communities present in residential areas and implanted forests on coastal dunes in Cariló. Eight fixed radius point counts were carried out in each habitat between spring 2021 and summer 2022. Both habitat types had similar values of species richness, Shannon and Simpson diversity, and functional diversity. However, residential habitat showed higher abundance than the forest. Significant changes between habitats in species composition were found. The Tropical Parula (Setophaga pitiayumi) and the Rufous-collared Sparrow (Zonotrichia capensis) were more abundant in the forest, while the Chimango Caracara (Phalcoboenus chimango), the Monk Parakeet (Myiopsitta monacha) and the Picazuró Pigeon (Patagioenas picazuro) were more abundant in the residential habitat. The residential area had a greater abundance of birds feeding on the ground, the canopy and the air. The results obtained suggest that the urban expansion on implanted forests promotes bird compositional changes, favoring species typical of semi-open habitats and impairing species associated with high tree cover and unmanaged herbaceous vegetation.

Shoreline Temporal Variability Inferred from Satellite Images at Mar del Plata, Argentina

Sandy beaches are fragile and dynamic coastal areas exposed to numerous environmental forcings. Systematic long-term data acquisition programs and exhaustive data series analyses are fundamental for a comprehensive understanding of the coastal processes. The software CoastSat was implemented to detect the shoreline position at beaches located to the south of Mar del Plata city (Buenos Aires Province, Argentina), by means of satellite images (period: 1986–2020). Tides in this area are mixed semidiurnal with a mean range of 1.74 m. The most frequent waves are characterized by significant wave heights from 0.5 to 2 m and periods of around 8 s propagating mainly from SSE. Seasonal and interannual variability and long-term trends of the shoreline position were investigated at Punta Mogotes (PM) bay, Faro Norte (FN) bay, and Ensenada Mogotes (EM). Seasonal cycles were noticed in the beach width variation series. In general, maximum accumulation was observed in summer and maximum erosion in winter. Exceptions were appreciated at southern PM bay (maximum accretion in autumn and maximum erosion in spring) and at FN bay (beach rotation on a seasonal scale). The drivers of seasonal variation are likely seasonal variations in the significant wave height and direction. PM bay showed a strong interannual variability with a clear alternating pattern between the northern and southern sectors of the bay, in an 8 ± 1.2 years period. Long-term trends showed a generalized erosion along 9 of the 12 km of the analyzed coast.

Effectiveness landscape of crop pollinator assemblages: Implications to pollination service management

There is a growing consensus that the world is facing a pollination crisis. To mitigate crop pollination deficits, some management strategies include the massive introduction of managed bee species, yet quite often they are applied blindly, as information on crop pollination effectiveness for each single pollinator species of assemblages is usually not available. Therefore, the introduction on managed species is not always the best option to improve crop yields. Here, by using the highly pollinator-dependent alfalfa crop (Medicago sativa L.) as a case study, we propose the use of the effectiveness landscape framework to identify key crop pollinator species. According to this framework, in a mutualistic interaction, each species´ effectiveness is represented by the product of a quantitative component and a qualitative one, these being measures of the outcomes of this interaction. We applied this framework for two managed and four wild bee species that visit alfalfa in fields southwest of Buenos Aires province, Argentina. We dissected the quantity components of the pollinator effectiveness landscape by estimating two quantitative subcomponents: visitation rate and flower tripping rate. Also, we estimate pod set as a qualitative component without dissecting it in subcomponents. Our results showed that the contribution of both components and the resulting pollinator effectiveness varied among pollinator species, indicating a contrasting effectiveness of different bee species on alfalfa pollination. For example, pollinator effectiveness was higher for managed than for wild bees, as consequence of their very high visitation rate, however, wild bee flower tripping rate and pod set were as high as managed ones. In fact, wild bees were more effective in promoting flower tripping than one of the managed bees (A. mellifera). This approach allowed us to assess which effectiveness components and subcomponents make pollinator species more or less effective, thus providing valuable information to identify key species to be enhanced to help in closing yield gaps. We suggest that the application of the effectiveness landscape framework would be useful to develop strategies to improve crop pollination service in pollinator-dependent crop systems.

Epidemiology of Leptospira spp. infection in a beef cattle area of Argentina.

Leptospirosis is an infectious disease caused by pathogenic Leptospira that affect humans and animals. This disease is complex and non-eradicable in nature. Therefore, the understanding of it is epidemiology in different environments is crucial to implement prevention and control measures. The prevalence of Leptospira infection in beef cattle farms is affected by multiple environmental, management and individual factors. In this study, a cross-sectional serological survey was carried on to estimate the prevalence of Leptospira antibodies in beef cattle in Tandil and Ayacucho Departments (Buenos Aires Province) and to identify risk factors and spatial clusters associated with seropositivity. Using a probabilistic two-stage sampling, 25 farms and 15 animals per farm were selected. The Microagglutination Test was used to analize all serum samples. Bivariate and multivariate analyses were performed. Seventy-three out of 375 cows were seropositive, representing a positivity rate of 19.47% (95% CI: 10.51-28.42), with Sejroe and Pomona being the most reactive serogroups: 9.33% (95% CI: 6.26-12.41) and 8.27% (95% CI: 5.35-11.19), respectively. The prevalence in Ayacucho was 23.11% (95% CI: 10.05-36.17), and in Tandil, 14% (95% CI: 3.25-24.75). The animals from Ayacucho presented 2.01 (1.16-3.49) more chances of being positive compared with those from Tandil (p < 0.01). After the Generalized Linear Mixed Model (GLMM) with random effect of farm-level risk, the presence of lagoons (OR: 7.32, 95% CI: 1.68-31.8, p < 0.05) and undulating terrain (OR: 0.24, 95% CI: 0.07-0.74, p < 0.05) were associated with bovine leptospirosis. Four spatial clusters with higher rates of seropositivity were detected. A new GLMM was performed with the significant variables detected in the first GLMM and a new variable, "being inside the spatial cluster," being the only one that remained significant (OR: 9.58, 95% CI: 3.39-27.08, p < 0.0001). The animals inside the clusters belonged to farms with a greater presence of creeks (OR: 9.03, 95% CI: 3.37-24.18, p < 0.0001), higher accumulated rainfall (OR: 1.01, 95% CI: 1-1.01, p < 0.0001) and less undulating terrain (OR: 0.18, 95% CI: 0.10-0.35, p < 0.0001). We conclude that Leptospira is seroprevalent in beef cattle in Tandil and Ayacucho Departments, especially in the latter, where the largest cattle farms are located. Prevalence of seropositivity animals was associated with selected environmental risk factors.

Morphological, Phylogenetic and Toxinological Characterization of Potentially Harmful Algal Species from the Marine Coastal Waters of Buenos Aires Province (Argentina)

In the framework of a monitoring program of harmful microalgae from the marine coastal waters of the Buenos Aires Province, seven strains were isolated and characterized by morphological and molecular analysis (LSU rDNA partial sequencing, D1–D3 regions). Established strains belonged to Alexandrium catenella, Protoceratium reticulatum and Pseudo-nitzschia multiseries. The toxinological profile of the target strains were determined by UHPLC-FLD equipment for paralytic shellfish toxins (PSTs) and LC-MS/MS for lipophilic (LSTs) and amnesic toxins (ASTs). The toxin profile varied in the four strains of A. catenella, the predominant compounds were gonyautoxins (GTXs) GTX2,3 and GTX1,4 for strains LPCc001 and LPCc004, and N-sulfocarbamoyl toxins (Cs) C1,2 and GTX1,4 for strains LPCc002 and LPCc008. The obtained cellular toxicity values were moderate-to-high (12.38–46.40 pg saxitoxin equiv. cell−1). The toxin profile of P. reticulatum was dominated by yessotoxins (YTXs) (up to 94.40 pg cell−1) accompanied by homo-yessotoxin (Homo-YTX) traces. In P. multiseries, the toxin profiles were dominated by domoic acid (DA) (1.62 pg cell−1 and 1.09 pg cell−1) and secondarily by Isomer A (Iso-A), Epi-domoic acid (Epi-DA), Isomer-E (Iso-E) and Isomer-D (Iso-D). This study provides detailed information about representative HAB species in the area, useful for resource management, risk evaluation and related research on toxic dinoflagellates and diatoms.

On the validity of the Macrochorobates scalabrinii Biozone (early Huayquerian Stage/Age, Late Miocene). Multi-proxy analysis of the enigmatic Arenas Blancas site (Buenos Aires Province, Argentina)

Arenas Blancas is a poorly known fossiliferous site located in the lower reach of the Chasicó creek (Buenos Aires Province, Argentina), with great relevance from a biostratigraphic viewpoint. The Macrochorobates scalabrinii Biozone was defined in this site, proposed as the biostratigraphic basis of the early Huayquerian Stage/Age (Late Miocene); however, the geological context and faunal record of this site have never been studied in detail. In this work, we perform a multi-proxy analysis of the Arenas Blancas site, as well as a nearby site here called Curva de la Vaca, and provide new interpretations on their origin, age, and biostratigraphy. Sedimentological, stratigraphic, and geomorphological characteristics of both sites suggest that the sequences include fluvial/alluvial deposits that represent Quaternary terraces. The taxonomic analysis of the Arenas Blancas faunal assemblage evidences the presence of 14 mammal taxa, together with some fishes, reptiles, and birds; the assemblage is correlated with the assemblage from the Cerro Azul Formation assigned to the Chasicoan Stage/Age (Late Miocene), also recovered from the lower reach of the Chasicó creek. The use of the taxa proposed in previous works to characterize the Macrochorobates scalabrinii Biozone (including this species) is not supported due to their taxonomic status and/or temporal distribution. Taphonomic evaluation indicates that the assemblage is constituted by reworked specimens; in this frame, it is proposed that fluvio/alluvial events, occurred during the Late Pleistocene-Holocene, eroded the Upper Miocene substrate and reworked fossil remains. Based on the present evidence, the Macrochorobates scalabrinii Biozone is here rejected as a valid biostratigraphic unit.

First assessment of debris pollution in the gastrointestinal content of juvenile Magellanic penguins (Spheniscus magellanicus) stranded on the west south Atlantic coasts

This paper provides the first evidence of debris pollution, including plastic, in juvenile Magellanic penguins (Spheniscus magellanicus) found stranded on the Atlantic coast of southern Buenos Aires Province, Argentina. Macro-, meso- and microparticles of anthropogenic origin were observed in 100 % of the studied birds, with debris abundance ranging between 33 and 200 items/bird. Microparticles represented 91 % of the total debris and 97 % of them were fibers. Black particles were the most abundant (30 %), followed by transparent (26 %), blue (14 %), yellow (10.3 %), and red (10 %). Infrared and Raman spectroscopy identified 62.7 % of the total particles as plastics, with polypropylene (27.8 %) and polyester (21.6 %) being the most abundant polymers. Semi-synthetic cellulosic fibers, metallic particles, and pigments were also found. The presence of metallic microparticles was suggested for the first time in penguins. Stranded juvenile Magellanic penguins are proposed as promising bioindicators of plastic pollution in the South Atlantic.

Unravelling the conoidean gastropods assigned to the genus Propebela (Gastropoda: Mangeliidae) from south-western Atlantic deep waters

ABSTRACT A new genus of conoidean gastropods of the family Mangeliidae, Notopropebela gen. nov., is herein described to include N. profunda (Castellanos and Landoni, 1993) previously in the genus Propebela Iredale, 1918, and two new species from the deep waters off south-western Atlantic Argentine. This new genus is characterised by small rhomboid shells with axial riblets and spiral cords, absent operculum, and radula of semi-enrolled marginal teeth. Both new species are distinguished from N. profunda by the presence of pustules covering the shell. Notopropebela pustulata sp. nov. was collected at depths ranging from 530 to 2845 m off Argentina within the Mar del Plata Submarine Canyon in the north and Burdwood Bank surroundings in the south. Notopropebela petu sp. nov., distinguished from N. pustulata by a larger spire and subsutural ramp, was described from material collected from 210 m off Buenos Aires province. The radula and details of the shell and protoconch of both new species were studied from material deposited in the collections of Museo Argentino de Ciencias Naturales (MACN) and Museo de La Plata (MLP). We conclude that the genus Propebela is absent from the south-western Atlantic. http://www.zoobank.org/urn:lsid:zoobank.org:pub:act:BABC3CF0-0301-43D5-8F61-01EB94F7D647 http://www.zoobank.org/urn:lsid:zoobank.org:pub:act:CA51AFD6-0C1D-49C2-91EE-BF3F7DBA3625 http://www.zoobank.org/urn:lsid:zoobank.org:pub:act:D0130F68-6631-4368-91B1-5E68AF0B3C85

First fossil record of Bibimys Massoia, 1979 (Rodentia, Cricetidae) from the Early Holocene in Argentina

ABSTRACT Argentinian fossil records of Bibimys have been well documented in a Late Pleistocene palaeontological site and several Late Holocene archaeological sites in Buenos Aires province. However, the specimen reported here is the first fossil record of this genus from the Early Holocene in Argentina. It was recovered in a fluvial unit dated at 9990 ± 140 yr B.P. from Doll creek, southwestern Entre Ríos province, Argentina. At present, this genus is distributed in the distal area of the Paraná River Delta in the province of Entre Ríos, represented by the species B. torresi, and in the province of Misiones, northern Corrientes, and eastern Chaco and Formosa, represented by the species B. chacoensis. The specimen described here is a contribution to the palaeobiogeography of the genus and to a better understanding of the fossil sigmodontine fauna that inhabited the southwest of the province of Entre Ríos in the recent past.

Appearances are deceptive: a cryptic lineage within the assumed distributional boundaries ofCtenomys talarum(Rodentia, Ctenomyidae)

AbstractThe coastal dunes of the southeast of Buenos Aires province, Argentina, present two different described species of tuco-tucos: Ctenomys talarum and C. australis. Formerly, C. talarum was subdivided into three subspecies (C. t. talarum, C. t. recessus, and C. t. occidentalis), mainly based on its geographic distribution and phenotypic variation in characters of external morphology (e.g., body size and pelage color). This study assesses the phylogenetic relationships of C. talarum, focusing on the populations at the western end of its coastal distribution (localities of Pehuen-Có and Sauce Grande), which have been previously identified as highly genetically divergent. In this regard, populations distributed throughout the range of the species were sampled. Complete DNA sequences of the mitochondrial cytochrome b gene (1,140 bp), partial sequences of the mitochondrial D-loop region (426 bp), and partial sequences of the nuclear DNA intron 8 of the β-fibrinogen (about 870 bp) gene were used for the analyses. Phylogenetic inferences based on mitochondrial and nuclear markers were performed separately or combined to obtain a species tree. Populations distributed at the western end of the coastal dunes (between Pehuen-Có and Sauce Grande), previously assumed as C. talarum, were found to belong to an independent lineage relative to the other populations from the Pampas region. The average genetic distance between these two lineages is within the order of the genetic distances observed between different species of the genus. Also, our results show that this lineage of Ctenomys presents a high affinity with the magellanicus group, which is distributed further south, in Patagonia. In conclusion, tuco-tuco populations occurring in the coastal expanse between these two localities should be considered a possible distinct cryptic species, highly differentiated from C. talarum.

The elucidation of the life cycle of Saccocoelioides nanii Szidat, 1954 (Digenea: Haploporidae) using molecular techniques.

In South America, the knowledge of trematode diversity parasitizing freshwater fishes is still scarce, as less than 5% of the freshwater fish fauna has been examined for parasites. A similar situation applies to studies on digenean life cycles, which have become increasingly rare. Among the digenean families parasitizing freshwater fishes in the region, Haploporidae is considered the richest in species diversity. However, information about the developmental stages of haploporid life cycles remains fragmentary. Particularly, in Argentina, nine cercariae attributed to the family Haploporidae have been described using morphological analysis, and only two life cycles of this family have been completely elucidated. In this study a new type of cercaria, morphologically assigned to the family Haploporidae and collected from the snail Heleobia parchappii (Cochliopidae) in Los Padres shallow lake, Buenos Aires province, was identified using morphological and molecular techniques. The molecular analysis, based on 28S and ITS2 sequences, revealed that the cercariae were 100% identical to adult specimens of Saccocoelioides nanii (Haploporidae) parasitizing the fish Prochilodus lineatus (Prochilodontidae) from Los Talas, Buenos Aires province. Our results not only provide information about the life cycle of S.nanii but also show that a molecular and morphological approach can be extremely useful in identifying the developmental stages of digeneans and elucidating their life cycles.

Synergy between infection control and antimicrobial stewardship programs to control carbapenem-resistant Enterobacterales.

Argentina is the third country in the world with the higher levels of CRE. The primary objective is to achieve an optimal result in the CRE infection rate after the implementation of an IPC program and antimicrobial stewardship programs (ASP) in a large teaching hospital in Argentina. Retrospective, observational study from January 2018 to December 2021, in a 220-bed tertiary care teaching hospital in Buenos Aires province. Actions aimed at CRE control and prevention included CRE and healthcare-associated infection (HAI) surveillance; compliance with hand hygiene, hospital hygiene, contact isolation precautions, and care bundles for the prevention of device-associated infections; optimization of antimicrobial treatments, antimicrobial consumption, education, and feedback. Synergy between an ICP and ASP achieved controlled rate of CRE infections reaching the lowest levels during 2020 (0.08 episodes/1000 patient days). Colonization rate remained stable throughout the study period. Ventilator-associated pneumonia (VAP) rate showed a trend toward lower rates. Compliance with care bundles showed rates >85%. Antimicrobial consumption increased slightly during the study period (15%). Among high-impact antimicrobials, only colistin consumption increased. Our study demonstrates the sustained and beneficial impact of an IPC Program and an ASP to control CRE infection.