Optimization of the biosynthesis of silver nanoparticles using bacterial extracts and their antimicrobial potential.

In the present study, silver nanoparticles (AgNPs) were biosynthesized using the supernatant and the intracellular extract of Cupriavidus necator, Bacillus megaterium, and Bacillus subtilis. The characterization of the AgNPs was carried out using UV-Vis spectroscopy, FTIR, DLS and TEM. Resazurin microtiter-plate assay was used to determine the antimicrobial action of AgNPs against Escherichia coli. UV-Visible spectra showed peaks between 414 and 460 nm. TEM analysis revealed that the synthesized AgNPs showed mostly spherical shapes. DLS results determined sizes from 20.8 to 118.4 nm. The highest antimicrobial activity was obtained with the AgNPs synthesized with supernatant rather than those using the intracellular extract. Therefore, it was determined that the bacterial species, temperature, pH, and type of extract (supernatant or intracellular) influence the biosynthesis. This synthesis thus offers a simple, environmentally friendly, and low-cost method for the production of AgNPs, which can be used as antibacterial agents.

Microbial composition of goat buck's ejaculates is modified by the process of preparing and storing refrigerated semen doses.

Ejaculates present their own microbiota, and a link between ejaculates' microbiota and sperm quality and fertility exists. With the development of artificial insemination in animal breeding, ejaculates must be manipulated by diluting them with extenders and storing them at temperatures below body temperature. The effects that these processes have on the original semen microbiota have never been studied. This study explores the effects of the protocol for preparing refrigerated goat buck semen doses and storing on seminal microbiota. Semen from six adult goat bucks of the Murciano-Granadina breed (24 ejaculates) was used, cooled to 4 °C in a skimmed milk-based extender, and stored at this temperature for 24 h. Samples were taken in different steps: in the raw ejaculates (ejaculates), after dilution with the refrigeration extender (diluted), immediately after reaching 4 °C (chilled 0 h) and the samples refrigerated at 4 °C and stored at this temperature for 24 h (chilled 24 h). Sperm quality (motility and integrity of plasma and acrosomal membrane, and mitochondrial functionality) was also evaluated. Bacterial 16S rRNA sequencing was used to study the seminal microbiota. Our results indicated that both refrigeration and storage at 4 °C negatively affected sperm quality parameters. Preparing semen doses and their subsequent conservation caused a significant change in the bacterial community structure. Raw ejaculates showed a lower Pielou's evenness index than the other samples (diluted, chilled 0 h and chilled 24 h). Ejaculates also had a lower Shannon's diversity index (3.44) than the diluted semen (4.17) and the semen chilled for 24 h (4.43). Regarding beta diversity, significant differences were detected between ejaculates and the other treatments. Differences were also found in unweighted UniFrac distances between the semen chilled for 0 h and that chilled for 24 h. At the genus level, marked effects of preparing doses and their subsequent conservation were also evident: 199 genera that were absent in ejaculates were found in the semen chilled and stored for 24 h; 177 genera that were present in ejaculates disappeared after 24-h refrigeration. In conclusion, the extender and protocol for preparing refrigerated goat buck semen doses considerably modify microbial ejaculate composition.

Gas Embolism in Pediatric Minimally Invasive Surgery: Should It Be a Concern?

Introduction: Gas embolism can occur during minimally invasive surgical procedures. Its incidence and implications in infants and children are not clear. The objective of this study is to identify gas embolism with transthoracic echocardiography and its consequences in pediatric laparoscopic appendectomy. Materials and Methods: This is a descriptive observational study including children undergoing laparoscopic appendectomy. We performed transthoracic echocardiography during surgery and collected data on intraoperative hemodynamic and respiratory parameters. Results: To date, we have included 10 patients in whom intraoperative transthoracic echocardiography revealed a 50% incidence of gas embolism. All episodes of embolism were grade I or II, and the patients remained asymptomatic. The hemodynamic and respiratory parameters varied slightly during the pneumoperitoneum. Conclusions: Episodes of gas embolism in pediatric laparoscopic appendectomy appeared in up to 50% of patients. Although they were subclinical, we should be aware of the risk of serious events and take measures to maximize safety in pediatric minimally invasive surgery.

Identification and Characterization of Common Bean (Phaseolus vulgaris) Non-Nodulating Mutants Altered in Rhizobial Infection.

The symbiotic N2-fixation process in the legume-rhizobia interaction is relevant for sustainable agriculture. The characterization of symbiotic mutants, mainly in model legumes, has been instrumental for the discovery of symbiotic genes, but similar studies in crop legumes are scant. To isolate and characterize common bean (Phaseolus vulgaris) symbiotic mutants, an ethyl methanesulphonate-induced mutant population from the BAT 93 genotype was analyzed. Our initial screening of Rhizobium etli CE3-inoculated mutant plants revealed different alterations in nodulation. We proceeded with the characterization of three non-nodulating (nnod), apparently monogenic/recessive mutants: nnod(1895), nnod(2353) and nnod(2114). Their reduced growth in a symbiotic condition was restored when the nitrate was added. A similar nnod phenotype was observed upon inoculation with other efficient rhizobia species. A microscopic analysis revealed a different impairment for each mutant in an early symbiotic step. nnod(1895) formed decreased root hair curling but had increased non-effective root hair deformation and no rhizobia infection. nnod(2353) produced normal root hair curling and rhizobia entrapment to form infection chambers, but the development of the latter was blocked. nnod(2114) formed infection threads that did not elongate and thus did not reach the root cortex level; it occasionally formed non-infected pseudo-nodules. The current research is aimed at mapping the responsible mutated gene for a better understanding of SNF in this critical food crop.

Effect of selection for growth rate on the rabbit (Oryctolagus cuniculus) immune system and its response after experimental Staphylococcus aureus infection.

The aim of the work was to evaluate if genetic selection for daily gain may affect the immune system. Two experiments were performed. The first one involved 80 rabbit females and their first two litters to explore the effect of selection on the ability of animals to maintain immune competence. Two generations from a line selected for average daily gain (ADG) were evaluated (VR19 generation 19th, n = 43; VR37 generation 37th, n = 37). In females, the effect of selection and its interaction with physiological state were not significant for any trait. In litters, the selection criterion increased the granulocyte to lymphocyte ratio. The second experiment involved 73 19-week-old females (VR19, n = 39; VR37, n = 34) to explore the effect of genetic selection on immune response after S. aureus infection. The VR37 rabbit females had lower counts for total lymphocytes, CD5+, CD4+, CD8+, CD25+, monocytes, the CD4+/CD8+ ratio and platelets than those of VR19 (-14, -21, -25, -15, -33, -18, -11 and -11%, respectively; P < 0.05). VR37 had less erythema (-8.4 percentage points; P < 0.05), fewer nodules (-6.5 percentage points; P < 0.05) and a smaller nodule size (-0.65 cm3 on 7 day post-inoculation; P < 0.05) compared to VR19. Our study suggests that genetic selection for average daily gain does not negatively affect the maintenance of a competent immune system or the ability to establish immune response. It seems that such selection may improve the response to S. aureus infections.

Microbiota in Goat Buck Ejaculates Differs Between Breeding and Non-breeding Seasons.

Changes in semen microbiota are associated with alterations to sperm quality and fertility. However, the microbiota from most livestock species has not yet been studied. Goats are seasonal breeders, but semen microbiota has never been described in this species, and it is unknown how seasonality affects it. Our study objective is 2-fold: to describe the microbiota in goat buck ejaculates and to determine if it differs between breeding and non-breeding seasons. Semen from six males of the Murciano-Granadina breed was collected during both seasons. Two replicates were performed per male and season on different days. The microbiota was characterized by genomic sequencing technology. Sperm quality was also evaluated. Repetition was not significant for the studied variables. Sperm velocities were higher for the breeding than for the non-breeding season. The ejaculates from both seasons also differed in the proportion of apoptotic spermatozoa. The five dominant phyla were Firmicutes, Proteobacteria, Fusobacteria, Actinobacteria, and Bacteroidetes during the breeding season and Firmicutes, Proteobacteria, Actinobacteria, Bacteroidetes, and Cyanobacteria during the non-breeding season. The dominant genus during both seasons was Ureaplasma. Differences in microbial community structure (the beta diversity) were found. A decrease in the relative abundance of the genus Faecalibacterium and an increase in the genera Sphingomonas and Halomonas were observed in the ejaculates collected during the breeding season. Sphingomonas and Faecalibacterium abundance favorably and unfavorably correlated with sperm quality, respectively. In conclusion, the semen microbiota from goat bucks varies between breeding and non-breeding seasons, and the microbiota remains stable for 7 days within a season. In addition, the genera Sphingomonas and Faecalibacterium could be possible biomarkers of semen quality in goat bucks. These results contribute to an in-depth understanding of the effects of reproductive seasonality on goat buck ejaculates.

Beneficio del empleo precoz de la oxigenoterapia nasal de alto flujo (ONAF) en pacientes con neumonía por SARS-CoV-2 / Benefits of early use of high-flow-nasal-cannula (HFNC) in patients with COVID-19 associated pneumonia

Introducción:La COVID-19 grave se asocia con una neumonía bilateral hipoxemiante, que desemboca en la necesidad de ventilación mecánica en un considerable número de pacientes. Hasta la fecha no existen recomendaciones acerca del momento óptimo para el inicio de la ONAF.Pacientes y métodos:Estudio retrospectivo de todos los pacientes ingresados por neumonía por COVID-19 y que precisaron ONAF entre marzo de 2020 y febrero de 2021. Se agruparon los pacientes en función del momento de inicio de la ONAF de acuerdo con la PaFi modificada.Resultados:Se incluyeron 53 pacientes, en 44 se inició la ONAF precozmente y en nueve de ellos se inició tardíamente. No existieron diferencias clínico-epidemiológicas significativas. La utilización precoz de la ONAF se asoció con una disminución de la necesidad de intubación (29,5 vs. 66,6%, p = 0,044), de la estancia hospitalaria (18,8 d vs. 36 d, p = 0,022) y de la mortalidad (22,7 vs. 55,5%, p = 0,061).Conclusiones:El empleo precoz de la ONAF se asocia con una disminución de la necesidad de intubación, de la mortalidad y de la estancia hospitalaria global. (AU)

Introduction:Severe COVID-19 is associated with hypoxemic bilateral pneumonia that leads to mechanical ventilation in a considerable proportion of patients. To the best of our knowledge, there are no recommendations about the best time to initiate high flow nasal cannula (HFNC).Patients and methods:Retrospective study of all patients admitted for COVID-19 pneumonia who required HNFO between March 2020 and February 2021. Patients were grouped in early HNFC or late HNFC, according to the modified Kirby index.Results:53 patients were included. Forty-four of them were included in the early HFNC and 9 in late HNFC. There were no statistically significant clinical-epidemiological differences. Early use of HFNC was associated with a decrease in the need for intubation (29.5 vs. 66.6%, p = 0.044), hospital stay (18.8 d vs. 36 d, p = 0.022) and mortality (22.7 vs. 55.5%, p = 0.061).Conclusions:Early HFNC use is associated with a decrease in the need for intubation, mortality and overall hospital stay. (AU)

Benefits of early use of high-flow-nasal-cannula (HFNC) in patients with COVID-19 associated pneumonia.

Introduction: Severe COVID-19 is associated with hypoxemic bilateral pneumonia that leads to mechanical ventilation in a considerable proportion of patients. To the best of our knowledge, there are no recommendations about the best time to initiate high flow nasal cannula (HFNC). Patients and methods: Retrospective study of all patients admitted for COVID-19 pneumonia who required HNFO between March 2020 and February 2021. Patients were grouped in early HNFC or late HNFC, according to the modified Kirby index. Results: 53 patients were included. Forty-four of them were included in the early HFNC and 9 in late HNFC. There were no statistically significant clinical-epidemiological differences. Early use of HFNC was associated with a decrease in the need for intubation (29.5 vs. 66.6%, p = 0.044), hospital stay (18.8 d vs. 36 d, p = 0.022) and mortality (22.7 vs. 55.5%, p = 0.061). Conclusions: Early HFNC use is associated with a decrease in the need for intubation, mortality and overall hospital stay.

Introducción: La COVID-19 grave se asocia con una neumonía bilateral hipoxemiante, que desemboca en la necesidad de ventilación mecánica en un considerable número de pacientes. Hasta la fecha no existen recomendaciones acerca del momento óptimo para el inicio de la ONAF. Pacientes y métodos: Estudio retrospectivo de todos los pacientes ingresados por neumonía por COVID-19 y que precisaron ONAF entre marzo de 2020 y febrero de 2021. Se agruparon los pacientes en función del momento de inicio de la ONAF de acuerdo con la PaFi modificada. Resultados: Se incluyeron 53 pacientes, en 44 se inició la ONAF precozmente y en nueve de ellos se inició tardíamente. No existieron diferencias clínico-epidemiológicas significativas. La utilización precoz de la ONAF se asoció con una disminución de la necesidad de intubación (29,5 vs. 66,6%, p = 0,044), de la estancia hospitalaria (18,8 d vs. 36 d, p = 0,022) y de la mortalidad (22,7 vs. 55,5%, p = 0,061). Conclusiones: El empleo precoz de la ONAF se asocia con una disminución de la necesidad de intubación, de la mortalidad y de la estancia hospitalaria global.

Quality of Life in Pediatric Minimally Invasive Surgery: Cost-Utility Analysis of Laparoscopic Versus Open Appendectomy.

Background: Economic evaluation in health care is becoming increasingly important. Laparoscopic appendectomy (LAp) is one of the most frequent minimally invasive procedures in the pediatric population. The increased costs of this approach in any indication could be justified by proving its cost-utility in terms of health-related quality of life (HRQoL). We aim to perform a cost-utility analysis between open and LAp (open appendectomy [OAp] and LAp). Materials and Methods: We included the data of children operated for acute noncomplicated appendicitis, who agreed to answer a validated quality of life (QoL) questionnaire. Costs were calculated for each patient. We established a threshold for cost-effectiveness (λ) of 20,000 to 30,000€ per quality adjusted life year (QALY) according to previous research. Results: A total of 53 patients were included. Overall mean costs in the OAp were 758.98€ and in the LAp 1525.50€. The incremental cost-effectiveness ratio was 18,000€/QALY, under the threshold of cost-effectiveness, therefore favoring the laparoscopic approach as it improves HRQoL despite the costs. Conclusions: Economic evaluation studies in Pediatric Surgery are scarce and rarely measure outcomes in terms of QoL. This information is important in the decision-making process for institutions and health-care professionals. Our results encourage the use of laparoscopy in pediatric appendectomy to improve HRQoL in our patients.

[Benefits of early use of high-flow-nasal-cannula (HFNC) in patients with COVID-19 associated pneumonia]. / Beneficio del empleo precoz de la oxigenoterapia nasal de alto flujo (ONAF) en pacientes con neumonía por SARS-CoV-2.

INTRODUCTION: Severe COVID-19 is associated with hypoxemic bilateral pneumonia that leads to mechanical ventilation in a considerable proportion of patients. To the best of our knowledge, there are no recommendations about the best time to initiate high flow nasal cannula (HFNC). PATIENTS AND METHODS: Retrospective study of all patients admitted for COVID-19 pneumonia who required HNFO between March 2020 and February 2021. Patients were grouped in early HNFC or late HNFC, according to the modified Kirby index. RESULTS: 53 patients were included. Forty-four of them were included in the early HFNC and 9 in late HNFC. There were no statistically significant clinical-epidemiological differences. Early use of HFNC was associated with a decrease in the need for intubation (29.5 vs. 66.6%, p = 0.044), hospital stay (18.8 d vs. 36 d, p = 0.022) and mortality (22.7 vs. 55.5%, p = 0.061). CONCLUSIONS: Early HFNC use is associated with a decrease in the need for intubation, mortality and overall hospital stay.

Prótesis unicompartimental de rodilla. Resultados clínico-radiográficos y análisis de la supervivencia del implante / Unicompartmental knee arthroplasty. Clinical-radiographic results and analysis of implant survival

Objetivo: Evaluar los resultados clínicos y radiográficos en pacientes sometidos a artroplastia unicompartimental de rodilla, así como la tasa de complicaciones y la supervivencia del implante. Materiales y Métodos: Estudio descriptivo retrospectivo de 68 pacientes consecutivos (70 rodillas) sometidos a artroplastia unicompartimental de rodilla entre 2013 y 2020, con un seguimiento medio de 57.7 meses (rango 24-105) y una media de la edad de 61 años (rango 34-79). El 46,5% eran hombres. El índice de masa corporal medio era de 29,9 (rango 20-39). El diagnóstico más frecuente fue la artrosis del compartimento femorotibial medial con un varo <7°. Los resultados se evaluaron con la escala analógica visual para dolor y el Knee Society Score (KSS). Se evaluó la incidencia de complicaciones y la tasa de supervivencia del implante. Resultados: La disminución media en la escala analógica visual para dolor fue de 4,4 ± 1,9. Las puntuaciones medias posoperatorias en las escalas funcional y clínica del KSS fueron de 77,4 ± 13,7 y 70,2 ± 17,7, respectivamente. La tasa de complicaciones posquirúrgicas fue del 7% (5 casos). La tasa de reintervención quirúrgica fue del 15,5% (11 pacientes): nueve casos por persistencia del dolor, uno por rigidez articular y otro por aflojamiento aséptico. Conclusiones: La artroplastia unicompartimental de rodilla es una opción terapéutica eficaz para pacientes con gonartrosis unicompartimental de rodilla; se logran buenos resultados clínicos con una aceptable tasa de complicaciones; sin embargo, la tasa de revisión del implante es considerable. Nivel de Evidencia: IV

Objective: To assess the clinical and radiological outcomes of patients who underwent a unicompartmental knee arthroplasty (UKA), as well as the complication rate and implant survival. Materials and Methods: We present a retrospective descriptive study of 68 consecutive patients (70 knees) who underwent UKA between 2013 and 2020, with an average follow-up of 57.7 mon-ths (range 24-105) and an average age of 61 years (range 34-79). 46.5% of the patients were male. The average BMI was 29.9 (range 20-39). The most frequent etiology was osteoarthritis of the medial femorotibial compartment with a varus <7°. To assess the outcomes, the visual analog scale (VAS) for pain and the Knee Society Score (KSS) were used. The complication and implant survival rates were evaluated. Results: The average decrease in the VAS pain scale was 4.4±1.9. The average score on the postoperative KSS functional and clinical scales were 77.4±13.7 and 70.2±17.7, respectively. The postoperative complication rate was 7% (5 cases). The surgical reoperation rate was 15.5% (11 patients): nine cases for persistent pain, one case for joint stiffness, and one case for aseptic loosening. Conclusions: UKA is an effective therapeutic option for patients with unicompartmental knee osteoarthritis, providing good clinical results with an acceptable rate of complications; however, it provides a considerable implant revision rate. Level of Evidence: IV

Control of the Rhizobia Nitrogen-Fixing Symbiosis by Common Bean MADS-Domain/AGL Transcription Factors.

Plants MADS-domain/AGL proteins constitute a large transcription factor (TF) family that controls the development of almost every plant organ. We performed a phylogeny of (ca. 500) MADS-domain proteins from Arabidopsis and four legume species. We identified clades with Arabidopsis MADS-domain proteins known to participate in root development that grouped legume MADS-proteins with similar high expression in roots and nodules. In this work, we analyzed the role of AGL transcription factors in the common bean (Phaseolus vulgaris) - Rhizobium etli N-fixing symbiosis. Sixteen P. vulgaris AGL genes (PvAGL), out of 93 family members, are expressed - at different levels - in roots and nodules. From there, we selected the PvAGL gene denominated PvFUL-like for overexpression or silencing in composite plants, with transgenic roots and nodules, that were used for phenotypic analysis upon inoculation with Rhizobium etli. Because of sequence identity in the DNA sequence used for RNAi-FUL-like construct, roots, and nodules expressing this construct -referred to as RNAi_AGL- showed lower expression of other five PvAGL genes highly expressed in roots/nodules. Contrasting with PvFUL-like overexpressing plants, rhizobia-inoculated plants expressing the RNAi_AGL silencing construct presented affection in the generation and growth of transgenic roots from composite plants, both under non-inoculated or rhizobia-inoculated condition. Furthermore, the rhizobia-inoculated plants showed decreased rhizobial infection concomitant with the lower expression level of early symbiotic genes and increased number of small, ineffective nodules that indicate an alteration in the autoregulation of the nodulation symbiotic process. We propose that the positive effects of PvAGL TF in the rhizobia symbiotic processes result from its potential interplay with NIN, the master symbiotic TF regulator, that showed a CArG-box consensus DNA sequence recognized for DNA binding of AGL TF and presented an increased or decreased expression level in roots from non-inoculated plants transformed with OE_FUL or RNAi_AGL construct, respectively. Our work contributes to defining novel transcriptional regulators for the common bean - rhizobia N-fixing symbiosis, a relevant process for sustainable agriculture.

Phaseolus vulgaris MIR1511 genotypic variations differentially regulate plant tolerance to aluminum toxicity.

The common-bean (Phaseolus vulgaris), a widely consumed legume, originated in Mesoamerica and expanded to South America, resulting in the development of two geographically distinct gene pools. Poor soil condition, including metal toxicity, are often constraints to common-bean crop production. Several P. vulgaris miRNAs, including miR1511, respond to metal toxicity. The MIR1511 gene sequence from the two P. vulgaris model sequenced genotypes revealed that, as opposed to BAT93 (Mesoamerican), the G19833 (Andean) accession displays a 58-bp deletion, comprising the mature and star miR1511 sequences. Genotyping-By-Sequencing data analysis from 87 non-admixed Phaseolus genotypes, comprising different Phaseolus species and P. vulgaris populations, revealed that all the P. vulgaris Andean genotypes and part of the Mesoamerican (MW1) genotypes analyzed displayed a truncated MIR1511 gene. The geographic origin of genotypes with a complete versus truncated MIR1511 showed a distinct distribution. The P. vulgaris ALS3 (Aluminum Sensitive Protein 3) gene, known to be important for aluminum detoxification in several plants, was experimentally validated as the miR1511 target. Roots from BAT93 plants showed decreased miR1511 and increased ALS3 transcript levels at early stages under aluminum toxicity (AlT), while G19833 plants, lacking mature miR1511, showed higher and earlier ALS3 response. Root architecture analyses evidenced higher tolerance of G19833 plants to AlT. However, G19833 plants engineered for miR1511 overexpression showed lower ALS3 transcript level and increased sensitivity to AlT. Absence of miR1511 in Andean genotypes, resulting in a diminished ALS3 transcript degradation, appears to be an evolutionary advantage to high Al levels in soils with increased drought conditions.

Validating 3D indexes in the non-surgical pectus excavatum patient.

BACKGROUND/PURPOSE: In recent years there has been an increased interest in three-dimensional (3D) imaging for the assessment of chest wall deformities. Some studies have proven a correlation between 3D and traditional cross-sectional images but only for patients who already had an indication for a computed tomography (CT) scan prior to surgery; mainly due to their severity. Our aim is to determine the accuracy and reliability of the measures obtained by a portable 3D scanner in a cohort of pectus excavatum (PE) patients with different severity grades, as well as in controls. METHODS: We conducted a study comparing radiological and optical indexes on magnetic resonance imaging (MRI) and 3D surface images. We used a hand-held 3D scanner to obtain the optical Haller Index (3DHI) and Correction Index (3DCI) and a limited MRI scan to obtain the traditional indexes. A statistical analysis was carried out to determine the correlation between optical and radiological measures, plus a subjective severity evaluation. RESULTS: Twenty-eight patients and controls were enrolled in the study. In both the control and PE groups, there was a significant positive correlation between the indexes, especially for the CI. There were no differences in correlation regarding gender, age or severity. CI appears to better discriminate amongst the different severity groups and controls. CONCLUSION: 3D surface imaging is feasible and appropriate to use to assess PE, regardless of the severity or characteristics of the individual patient. Even with a small hand-held device, we can obtain accurate images and measures which are especially useful for the assessment of the nonsurgical pectus patient.

Marked Presence of Methicillin-Resistant Staphylococcus aureus in Wild Lagomorphs in Valencia, Spain.

The appearance of methicillin-resistant strains of Staphylococcus aureus (MRSA) in several animal species (including rabbits) has set off alarms for their capacity to act as reservoirs for this bacterium. This is especially important in wild animals given its epidemiological implications. The objectives of this study were to identify and characterize S. aureus, specifically MRSA, strains in wild lagomorph high-density areas. Ten hares and 353 wild rabbits from 14 towns with a high rabbit density in the Valencian region (eastern Spanish coast) were sampled. Swabs from the nasal cavity, ears, perineum and lesions (when present) were taken for microbiological studies. The detection of different genes and antibiotic susceptibility studies were also carried out. Of all the animals, 41.3% were positive for S. aureus, of which 63.3% were MRSA. Ears were the anatomical location with more S. aureus and MRSA strains. The more frequently identified MLST type was ST1945 (97.1%, 136/140). The mecA gene was found only in one sample. The rest (n = 139) carried the mecC gene and were included in CC130, except one. Penicillin resistance was detected in 28 mec-negative isolates and, in one case, bacitracin resistance. mecA isolate presented resistance to enrofloxacin and tetracycline, and 10 mecC isolates also showed bacitracin resistance. No MRSA isolate was positive for genes chp, sea, tst and PVL. Two ST1945 isolates contained IEC type E (comprising genes scn and sak). mecA-isolate was positive for blaZ. Of the 28 MSSA strains showing resistance to penicillin, 22 carried the blaZ gene. These surprising results highlight the marked presence of MRSA strains in wild rabbits in high-density areas.

Experiencia inicial con el uso de un escáner tridimensional portátil / Initial experience with the use of a portable 3-dimensional scanner

No disponible

Pathogenesis of Intradermal Staphylococcal Infections: Rabbit Experimental Approach to Natural Staphylococcus aureus Skin Infections.

Despite the enormous efforts made to achieve effective tools that fight against Staphylococcus aureus, the results have not been successful. This failure may be due to the absence of truly representative experimental models. To overcome this deficiency, the present work describes and immunologically characterizes the infection for 28 days, in an experimental low-dose (300 colony-forming units) intradermal model of infection in rabbits, which reproduces the characteristic staphylococcal abscess. Surprisingly, when mutant strains in the genes involved in virulence (JΔagr, JΔcoaΔvwb, JΔhla, and JΔpsmα) were inoculated, no strong effect on the severity of lesions was observed, unlike other models that use high doses of bacteria. The inoculation of a human rabbitized (FdltBr) strain demonstrated its capacity to generate a similar inflammatory response to a wild-type rabbit strain and, therefore, validated this model for conducting these experimental studies with human strains. To conclude, this model proved reproducible and may be an option of choice to check both wild-type and mutant strains of different origins.

Differences in virulence between the two more prevalent Staphylococcus aureus clonal complexes in rabbitries (CC121 and CC96) using an experimental model of mammary gland infection.

Staphylococcal mastitis is a major health problem in humans and livestock that leads to economic loss running in millions. This process is currently one of the main reasons for culling adult rabbit does. Surprisingly, the two most prevalent S. aureus lineages isolated from non-differentiable natural clinical mastitis in rabbits (ST121 and ST96) generate different immune responses. This study aimed to genetically compare both types of strains to search for possible dissimilarities to explain differences in immune response, and to check whether they showed similar virulence in in vitro tests as in experimental intramammary in vivo infection. The main differences were observed in the enterotoxin gene cluster (egc) and the immune-evasion-cluster (IEC) genes. While isolate ST121 harboured all six egc cluster members (seg, sei, selm, seln, selo, selu), isolate ST96 lacked the egc cluster. Strain ST96 carried a phage integrase Sa3 (Sa3int), compatible with a phage integrated into the hlb gene (ß-haemolysin-converting bacteriophages) with IEC type F, while isolate ST121 lacked IEC genes and the hlb gene was intact. Moreover, the in vitro tests confirmed a different virulence capacity between strains as ST121 showed greater cytotoxicity for erythrocytes, polymorphonuclear leukocytes and macrophages than strain ST96. Differences were also found 7 days after experimental intramammary infection with 100 colony-forming units. The animals inoculated with strain ST121 developed more severe gross and histological mastitis, higher counts of macrophages in tissue and of all the cell populations in peripheral blood, and a significantly larger total number of bacteria than those infected by strain ST96.

Characterization of Livestock-Associated Methicillin-Resistant Staphylococcus aureus Isolates Obtained From Commercial Rabbitries Located in the Iberian Peninsula.

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have been a growing problem in human medicine since the 1960s, and more recently in veterinary medicine with the appearance of livestock-associated MRSA (LA-MRSA). Nevertheless, information about the presence of MRSA in rabbits is quite scarce since only one LA-MRSA identification has been previously reported. The present study aimed to determine genotypic characterization by verifying the presence of resistance determinants, virulence, and toxin genes of different S. aureus strains that cause lesions in rabbits, and their phenotypic traits based on the antimicrobial susceptibility profile. The analysis of 240 S. aureus isolates obtained from different lesion types collected from 89 Spanish and Portuguese rabbit commercial farms in the last 4 years (2014-2017) was performed. The methicillin-resistant gene mecA was found in 11.25% of the studied isolates (27 of 240) from 19 farms (13 Spanish and 6 Portuguese). Staphylococcal cassette chromosome mec (SCCmec) typing predominantly revealed type III (n = 15). Additionally, three MRSA isolates carrying the mecC gen were detected in samples from three different farms (two Spanish and one Portuguese). None of the 30 MRSA isolates was PVL-positive or tst-positive. After the multilocus sequence typing (MLST) procedure, 16 belonged to ST2855, 6 to ST146, 6 to ST398, and 2 ST4774. No ST121 isolate was mec-positive. ST398 and ST4774 isolates lacked the immune-evasion-cluster (IEC) genes. ST2855 strains were associated with the presence only of the sak gene, and ST146 isolates were ascribed to IEC type E. Therefore, this is the first description of LA-MRSA from rabbits belonging to ST2855. Interestingly, one ST2855 and two ST4774 isolates were mecC-positive, which could act as a mecC-MRSA reservoir. More studies are needed to further characterize these isolates and their relationship with humans and other animal species.