Multiclonal human origin and global expansion of an endemic bacterial pathogen of livestock.

Most new pathogens of humans and animals arise via switching events from distinct host species. However, our understanding of the evolutionary and ecological drivers of successful host adaptation, expansion, and dissemination are limited. Staphylococcus aureus is a major bacterial pathogen of humans and a leading cause of mastitis in dairy cows worldwide. Here we trace the evolutionary history of bovine S. aureus using a global dataset of 10,254 S. aureus genomes including 1,896 bovine isolates from 32 countries in 6 continents. We identified 7 major contemporary endemic clones of S. aureus causing bovine mastitis around the world and traced them back to 4 independent host-jump events from humans that occurred up to 2,500 y ago. Individual clones emerged and underwent clonal expansion from the mid-19th to late 20th century coinciding with the commercialization and industrialization of dairy farming, and older lineages have become globally distributed via established cattle trade links. Importantly, we identified lineage-dependent differences in the frequency of host transmission events between humans and cows in both directions revealing high risk clones threatening veterinary and human health. Finally, pangenome network analysis revealed that some bovine S. aureus lineages contained distinct sets of bovine-associated genes, consistent with multiple trajectories to host adaptation via gene acquisition. Taken together, we have dissected the evolutionary history of a major endemic pathogen of livestock providing a comprehensive temporal, geographic, and gene-level perspective of its remarkable success.

The polymicrobial nature of the oral cavity and claws of cats diagnosed by mass spectrometry and next-generation sequencing.

Close contact between cats and humans increases the risk of transmission of zoonotic pathogens, through bites and scratches due to the complexity of microorganisms in the oral and nail microbiotas of felines. This study investigated the presence of bacteria and fungi in the oral cavity and claws of 100 apparently healthy cats using conventional and selective microbiological culture media, and next-generation sequencing (NGS) and mass spectrometry (MALDI-TOF MS). Furthermore, antimicrobial susceptibility testing of bacteria isolates was performed by disc diffusion method. In total, 671 bacteria and 33 yeasts were identified by MALDI-TOF MS. Neisseria animaloris (10.8 %), Staphylococcus felis (8.5 %), and Pasteurella multocida (7 %) were the most prevalent bacteria in oral cavity samples (n = 343), while the most common yeast (n = 19) was Candida albicans (68.4 %). Staphylococcus pettenkoferi (13.4 %), Staphylococcus felis (6.4 %), and Staphylococcus simulans (5.8 %) were the prevalent bacteria identified in the claw samples (n = 328), while Rhodotorula mucilaginosa (57.2 %) was the most common yeast (n = 14). NGS predominantly identified the genera Moraxella, Neisseria, Pasteurella, and Fusobacterium in oral cavity samples, whereas enterobacteria and staphylococci were prevalent in nail bed samples. In addition, the genera Capnocytophaga and Bartonella were identified, which have been described in serious human infections secondary to feline aggressions. Levofloxacin, marbofloxacin, and amoxicillin/clavulanic acid were the most effective drugs against the main groups of bacteria identified. Multidrug resistance was observed in 17 % of the bacterial isolates. Furthermore, three staphylococci harboring the methicillin resistance gene mecA were identified. We highlight the complexity of microorganisms inhabiting the oral/claw microbiotas of cats, the high resistance rate of the isolates to conventional antimicrobial agents, and the zoonotic risk of aggressions caused by bites and scratches from domestic cats.

Virulence-encoding genes related to extraintestinal pathogenic E. coli and multidrug resistant pattern of strains isolated from neonatal calves with different severity scores of umbilical infections.

Umbilical infections in calves comprise a major cause of neonatal mortality and have been related to a variety of microorganisms. E. coli is an opportunistic enteropathogen characterized by a diversity of virulence factors (VF). Nonetheless, the gene profiles that encode VF associated with umbilical infections in calves and their effect on the clinical severity remains unclear. In this scenario, microbial identification (with an emphasis on E. coli), was carried out among 150 neonatal calves (≤30 days of age) with umbilical infections, where the omphalopathies were clinically scored as mild, moderate, or severe. Also, a panel of 16 virulence-encoding genes related to extraintestinal pathogenic E. coli (ExPEC) were investigated, i.e., fimbriae/adhesins (sfa/focDEa, papA, papC, afaBC), toxins (hlyA, sat, cnf1, cdt), siderophores (iroN, irp2, iucD, ireA), invasins (ibeA), and serum resistance (ompT, traT, kpsMT II). Bacteria and yeasts isolates were identified using mass spectrometry. Bacteria, yeasts, and fungi were isolated in 94.7% (142/150) of neonatal calves sampled. E. coli was the agent most frequently isolated (59/150 = 39.3%), in pure culture (27/59 = 45.8%) and combined infections (32/59 = 54.2%), although a great variety (n = 83) of other species of microorganisms were identified. Clinical severity scores of 1, 2, and 3 were observed in 32.2% (19/59), 23.7% (14/59), and 44.1% (26/59) of E. coli infections, respectively. The ExPEC genes detected were related to serum resistance (traT, 42/59 = 72.2%; ompT, 35/59 = 59.3%, kpsMTII, 10/59 = 17%), invasins (ibeA, 11/59 = 18.6%), siderophores (iucD, 9/59 = 15.3%; iroN, 8/59 = 13.6%), and adhesins/fimbriae (papA, 8/59 = 13.6%; papC, 15/59 = 9.6%). The presence of each virulence gene was not associated with the case's clinical score. Among all isolates, 89.8% (53/59) showed in vitro resistance to sulfamethoxazole/trimethoprim and 59.3% to ampicillin (35/59), while 94.1% (55/59) revealed a multidrug resistant profile. Great complexity of bacteria, yeast, and fungi species was identified, reinforcing the umbilical infections of neonatal calves as a polymicrobial disorder. The high occurrence of E. coli (39.3%) highlights the role of this pathogen in the etiology of umbilical infections in calves. Furthermore, a panel of ExPEC genes was investigated for the first time among calves that were clinically scored for case severity. The high prevalence of traT and ompT indicates that these serum resistance-related genes could be used as biomarkers for further investigations of ExPEC isolates from umbilical infections. Our results contribute to the etiological investigation, clinical severity scoring, antimicrobial resistance pattern, and virulence-related to ExPEC genes involved in umbilical infections of neonatal calves.

MALDI-TOF bacterial subtyping for rapid detection of biomarkers in Staphylococcus aureus from subclinical bovine mastitis.

AIMS: This study aimed to evaluate matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) bacterial subtyping for the rapid detection of biomarkers in Staphylococcus aureus from subclinical bovine mastitis. METHODS AND RESULTS: A total of 229 S. aureus isolates were obtained from milk samples collected from cows with subclinical mastitis using microbiological culture. Staphylococcus aureus isolates were also submitted to PCR analysis targeting the mecA and mecC genes, which are indicative of methicillin resistance. Confirmation of the species was achieved through MALDI-TOF MS analysis. To analyze antimicrobial resistance patterns, the MALDI BioTyper Compass Explorer and ClinProTools Bruker software were employed, and dendrograms were generated using Bionumerics software. CONCLUSIONS: MALDI-TOF MS successfully identified S. aureus at the species level, but no methicillin resistance was observed. Moreover, spectral typing displayed limited similarity when compared to pulsed-field gel electrophoresis (PFGE).

Identification of Escherichia coli isolated from flies (Insecta: Diptera) that inhabit the environment of dairy farms harboring extraintestinal virulence markers.

AIMS: We investigate extraintestinal pathogenic genes (ExPEC) related to virulence of Escherichia coli in flies from the dairy environment. METHODS AND RESULTS: We collected 217 flies from nine dairy farms, which were submitted to microbiological culture. Fifty-one E. coli were identified using mass spectrometry. Eleven dipteran families were identified, with a predominance of Muscidae, and a minor frequency of Tachinidae, Drosophilidae, Sphaeroceridae, Ulidiidae, Syrphidae, Chloropidae, Calliphoridae, Sarcophagidae, and Piophilidae. A panel of 16 virulence-encoding genes related to ExPEC infections were investigated, which revealed predominance of serum resistance (traT, 31/51 = 60.8%; ompT, 29/51 = 56.9%), iron uptake (irp2, 17/51 = 33.3%, iucD 11/51 = 21.6%), and adhesins (papC, 6/51 = 11.8%; papA, 5/51 = 9.8%). CONCLUSIONS: Our findings reveal Dipterans from milking environment carrying ExPEC virulence-encoding genes also identified in clinical bovine E. coli-induced infections.

Characterization of mammary pathogenic Escherichia coli reveals the diversity of Escherichia coli isolates associated with bovine clinical mastitis in Brazil.

Mammary pathogenic Escherichia coli (MPEC) is one of the most common pathogens associated with clinical mastitis. We analyzed isolates obtained from milk samples of cows with clinical mastitis, collected from 10 farms in Brazil, to verify molecular and phenotypic characteristics. A total of 192 (4.5%) mammary pathogenic E. coli isolates were obtained from 4,275 milk samples analyzed, but we tested 161. We assigned most of these isolates to E. coli phylogroups B1 (52.8%) and A (36.6%), although phylogroups B2, C, D, E, and unknown also occurred. All isolates were assessed for the presence of several genes encoding virulence factors, such as adhesins (sfaDE, papC, afaBC III, ecpA, fimH, papA, and iha), toxins (hlyA, cnf1, sat, vat, and cdt), siderophores (iroN, irp2, iucD, ireA, and sitA), an invasion protein (ibeA), and serum resistance proteins (traT, KpsMTII, and ompT), and isolates from phylogroups B1, B2, and E showed up to 8 genes. Two isolates harbored the locus of enterocyte effacement (escN+) and lack the bundle-forming pilus (bfpB-) operon, which corresponds to a molecular profile of a subgroup of diarrheagenic E. coli (aEPEC), thus being classified as hybrid MPEC/aEPEC isolates. These isolates displayed a localized adherence-like pattern of adherence in HeLa cells and were able to promote F-actin polymerization underneath adherent bacteria. Based on the pulsed-field gel electrophoresis analyses, considerable genetic variability was observed. A low index of antimicrobial resistance was observed and 2 extended-spectrum ß-lactamase-producing E. coli were identified, both harboring blaCTX-M15 gene, and were classified as ST10 and ST993 using multilocus sequence typing. A total of 148 (91.2%) isolates were weak biofilm producers or formed no biofilm. Because raw milk is still frequently consumed in Brazil, the occurrence of virulence factor-encoding genes from extraintestinal or diarrheagenic E. coli added to the presence of extended-spectrum ß-lactamase-producing isolates can turn this veterinary medicine problem into a public health concern.

Special Issue "Recent Advances in the Synthesis, Functionalization and Applications of Pyrazole-Type Compounds II".

Pyrazole and its derivatives are considered privileged N-heterocycles with immense therapeutic potential [...].

Distance decay 2.0 - A global synthesis of taxonomic and functional turnover in ecological communities.

Aim: Understanding the variation in community composition and species abundances (i.e., ß-diversity) is at the heart of community ecology. A common approach to examine ß-diversity is to evaluate directional variation in community composition by measuring the decay in the similarity among pairs of communities along spatial or environmental distance. We provide the first global synthesis of taxonomic and functional distance decay along spatial and environmental distance by analysing 148 datasets comprising different types of organisms and environments. Location: Global. Time period: 1990 to present. Major taxa studied: From diatoms to mammals. Method: We measured the strength of the decay using ranked Mantel tests (Mantel r) and the rate of distance decay as the slope of an exponential fit using generalized linear models. We used null models to test whether functional similarity decays faster or slower than expected given the taxonomic decay along the spatial and environmental distance. We also unveiled the factors driving the rate of decay across the datasets, including latitude, spatial extent, realm and organismal features. Results: Taxonomic distance decay was stronger than functional distance decay along both spatial and environmental distance. Functional distance decay was random given the taxonomic distance decay. The rate of taxonomic and functional spatial distance decay was fastest in the datasets from mid-latitudes. Overall, datasets covering larger spatial extents showed a lower rate of decay along spatial distance but a higher rate of decay along environmental distance. Marine ecosystems had the slowest rate of decay along environmental distances. Main conclusions: In general, taxonomic distance decay is a useful tool for biogeographical research because it reflects dispersal-related factors in addition to species responses to climatic and environmental variables. Moreover, functional distance decay might be a cost-effective option for investigating community changes in heterogeneous environments.

Quality of dialysis water and dialysate in haemodialysis centres: Highlight for occurrence of non-fermenting gram-negative bacilli.

AIMS: To evaluate the physicochemical and microbiological quality of dialysis water and dialysate samples from haemodialysis centres. METHODS AND RESULTS: Samples were fortnightly collected from three haemodialysis centres in Bauru City, Brazil, between July 2017 and June 2018, at the stages of post-reverse osmosis, reuse and dialysate. Analyses included determination of conductivity, fluoride, nitrate and sulphate; test for total coliform bacteria; count of heterotrophic bacteria; count and identification of non-fermenting gram-negative bacilli (NFGNB); drug susceptibility test; biofilm formation capacity; and genetic similarity among some isolated NFGNB. Of the analysed samples, only 4/72 (5.6%) had conductivity values ≥10 mS/cm, 4/216 (1.9%) presented total coliforms and 1/216 (0.5%) had heterotrophic bacteria count >100 CFU/ml. NFGNB were isolated from 99/216 (45.8%) samples, and the major identified micro-organisms included Herbaspirillum aquaticum/huttiense, Brevundimonas aurantiaca, Cupriavidus metallidurans, Pseudomonas aeruginosa and Ralstonia insidiosa. Isolates of P. aeruginosa and Burkholderia cepacia complex were sensitive to most antimicrobials and, together with isolates of Ralstonia insidiosa and Ralstonia pickettii, showed strong biofilm formation capacity. Some isolates expressed the same electrophoretic profile on pulsed-field gel electrophoresis, indicating the persistence of bacterial clones in the systems over time. CONCLUSIONS: NFGNB were observed in several dialysis water and dialysate samples from all investigated centres, which may represent a risk to the health of patients. SIGNIFICANCE AND IMPACT OF THE STUDY: Regular inclusion of actions for NFGNB control and monitoring in haemodialysis fluids are suggested for greater safety of the dialytic process.

Revisiting the Chemistry of Vinylpyrazoles: Properties, Synthesis, and Reactivity.

Vinylpyrazoles, also known as pyrazolyl olefins, are interesting motifs in organic chemistry but have been overlooked. This review describes the properties and synthetic routes of vinylpyrazoles and highlights their versatility as building blocks for the construction of more complex organic molecules. Concerning the reactivity of vinylpyrazoles, the topics surveyed herein include their use in cycloaddition reactions, free-radical polymerizations, halogenation and hydrohalogenation reactions, and more recently in transition-metal-catalyzed reactions, among other transformations. The current state of the art about vinylpyrazoles is presented with an eye to future developments regarding the chemistry of these interesting compounds. Styrylpyrazoles were not considered in this review, as they were the subject of a previous review article published in 2020.

Association between antimicrobial use and antimicrobial resistance of Streptococcus uberis causing clinical mastitis.

It is unknown whether overuse of antimicrobials against clinical mastitis (CM) from Streptococcus uberis is associated with increased antimicrobial resistance (AMR). Therefore, the aim of this study was to evaluate the association between antimicrobial use (AMU) and AMR in relation to the Strep. uberis causing CM in dairy herds. A total of 83 Strep. uberis isolates were selected from a collection created during a previous study evaluating the epidemiology of CM in dairy herds (n = 17) of southeastern Brazil. For each case of CM identified on farm, the following information was recorded: cow's identification number, affected mammary quarter, date of CM diagnosis, antimicrobial commercial names, number of administrations, and descriptions of protocol changes during the treatment. Streptococcus uberis isolates were confirmed by conventional culture, MALDI-TOF mass spectrometry, and quantitative multiplex PCR analyses. Thus, a total of 8 antimicrobials commonly used for CM treatment were evaluated for antimicrobial activity against Strep. uberis isolates. The minimum inhibitory levels of antimicrobials were determined at the lowest concentrations able to inhibit 50 and 90%, respectively, of Strep. uberis isolates. Data related to the antibiotics used for treatment of CM was used to calculate the frequency of administered antimicrobials as the number of defined daily doses (DDD). The highest frequencies of resistant Strep. uberis were observed for erythromycin (80.7% resistant, R), tetracycline (R = 59%), and penicillin G (R = 57.8%), whereas against ceftiofur only 10.8% of Strep. uberis isolates were resistant, and only 1.2% of the Strep. uberis isolates were resistant to enrofloxacin. Regarding the evaluation of resistance for antimicrobial classes, the highest frequency was observed for macrolides (R = 80.7%; 19.3% susceptible, S). Additionally, a frequency of 18.7% of Strep. uberis isolates were resistant to cephalosporins (S = 81.3%), respectively. Further, 94% of Strep. uberis isolates were multiresistant; all these isolates presented resistance to at least 3 different antimicrobial classes. The overall monthly average of antimicrobial treatment incidence (ATI) among the 17 herds enrolled in the study was 23.7 DDD per 1,000 lactating dairy cows [standard deviation (SD) = 13.9], ranging from 5.0 to 55.4 DDD per 1,000 cows in lactation-day. Cephalosporins and penicillins were the most commonly used antimicrobial classes among the evaluated herds (n = 16; 94.1%), followed by tetracyclines (n = 15 herds; 88.2%), fluoroquinolones (n = 14; 82.3%), and sulfonamides (n = 14; 82.3%). The tetracycline class had the highest ATI mean (5.0 DDD per 1,000 lactating cow-days, SD = 5.8), followed by fluoroquinolones (4.7 DDD per 1,000 lactating cow-days, SD = 6.0) and cephalosporins (3.8 DDD per 1,000 lactating cow-days, SD = 6.0). The overall use of antimicrobials was associated with the resistance of Strep. uberis to the antimicrobial tetracycline.

Short communication: Association between the accessory gene regulator (agr) group and the severity of bovine mastitis caused by Staphylococcus aureus.

Staphylococcus aureus can elicit mild to more severe degrees of mastitis in cattle, depending on the response of the host's immune system and the virulence factors of the specific isolate. Several virulence factors are controlled by a global regulatory system, designated accessory gene regulator (agr). Thus, the objective was to examine associations between different capsular and agr types and the severity of bovine mastitis caused by S. aureus. All isolates were obtained from bovine subclinical (n = 50), mild clinical (n = 73), and moderate clinical mastitis cases (n = 28). Isolates containing the agrI gene and lacking the agr locus (agr-) were more prevalent among subclinical than clinical mastitis cases, whereas isolates containing the agrII and agrIII genes were more prevalent among clinical mastitis cases. The capsular types 5 (cap5) and 8 (cap8) were found in 42 and 44%, respectively, of the isolates obtained from subclinical cases and in 38.6 and 58.4%, respectively, of those isolated from clinical mastitis cases. Capsular type was not associated with type of mastitis (subclinical, mild clinical, or moderate clinical). We found a strong association between agr type and type of mastitis, suggesting that knowledge of S. aureus genetic profiles could be an additional tool to control this disease.

Special Issue "Recent Advances in the Synthesis, Functionalization and Applications of Pyrazole-Type Compounds".

Pyrazoles and their reduced form, pyrazolines, are considered privileged scaffolds in medicinal chemistry, owing to their remarkable biological activities, physicochemical properties and occurrence in many low-molecular-weight compounds present in several marketed drugs (e [...].

Biofilm production under different atmospheres and growth media by Streptococcus agalactiae isolated from milk of cows with subclinical mastitis.

Different methods to analyze Streptococcus agalactiae biofilm formation have been investigated, but standardized protocols have not been developed. We compared S. agalactiae biofilm production among different atmospheres and growth media. Biofilm formation was studied in 32 isolates from bovine mastitis cases grown in Tryptone Soy Broth (TSB), Todd Hewitt Broth (THB), Luria Bertani Broth (LB) and Brain Heart Infusion (BHI), under two atmospheres, aerobic and 5% CO2. Regardless of the culture medium, growth under 5% CO2 resulted in a greater proportion of biofilm formation (65.63%), as compared with aerobic conditions (39.84%). Regardless of the atmosphere, the chances of biofilm formation were greater for isolates grown in TSB, as compared with THB [Odds ratio (OR) = 3.02], BHI (OR = 4.57), or LB (OR = 10.20). Thus, we suggest the use of 5% CO2 atmosphere and TSB in biofilm formation assays by Group-B streptococci (GBS) isolated from intramammary infections.

Chalcones as Modulators of Neutrophil Oxidative Burst under Physiological and High Glucose Conditions.

Several epidemiological studies indicate that neutrophils, under hyperglycemic conditions, are involved in the perpetuation of the inflammatory status, a characteristic of diabetes mellitus, leading to the production of prodigious quantities of reactive species and the release of neutrophil extracellular traps (NETs). Accordingly, our aim was to study the ability of a panel of 25 structurally related chalcones to modulate human neutrophil oxidative burst and the production of NETs under physiological and high glucose conditions. In general, all chalcones presented similar effects under physiological and high glucose conditions. 2',4-Dihydroxy-3-methoxychalcone (3), here studied for the first time, was the most active (IC50 ≤ 5 µM) on the inhibition of neutrophil oxidative burst, showing the importance of the presence of hydroxy substituents at the C-2' and C-4 positions of the A and B rings, respectively, and a 3-methoxy substituent at B ring of the chalcone scaffold. In the present experimental conditions, NETs release only occurred under high glucose levels. The pentahydroxylated chalcone 1 was the only one that was able to modulate the NETs release. This study provided important considerations about the chalcones' scaffold and their modulatory effect on human neutrophil activities at physiological and high glucose conditions, evidencing their potential use as complementary antidiabetic agents.

First investigation of Staphylococcus argenteus in a Brazilian collections of S. aureus isolated from bovine mastitis.

BACKGROUND: Staphylococcus argenteus is a new specie positive coagulase staphylococci. We investigate the presence of S. argenteus in isolates previously classified as S. aureus, obtained from the milk of cows with mastitis in Brazil. RESULTS: Among 856 S. aureus tested in chocolate agar, tryptone soya agar and salt egg yolk agar, white or colorless colonies were observed in 185 (21.6%) isolates. Regarding the ctrOPQMN operon, 111 (60%) presented the complete cluster. Despite some missing genes in this cluster, the remaining strains (74) were confirmed as S. aureus using the nrps gene. CONCLUSIONS: As far as we know, this is the first review of S. aureus collection in Brazil and S. argenteus does not appear to be a significant problem in Brazilian herds.

Potassium usnate, a water-soluble usnic acid salt, shows enhanced activity against Schistosoma mansoni in vitro.

Here, we report enhanced the in vitro effect of potassium usnate on coupled adult Schistosoma mansoni worms at different time intervals and concentrations. The evaluated schistosomicidal parameters were the following: motility, mortality, fecundity and integumentary changes, as viewed in photomicrographs. Potassium usnate was able to cause 100 and 50% mortality at 100 and 50 µM concentrations, respectively, after 24 h of exposure, while 25 and 12.5 µM concentrations caused changes in motility at 48 and 72 h, and lethality at 96 and 120 h respectively. Eggs were not detected at any of the concentrations analyzed. Photomicrographs revealed morphological tegument alterations within all periods of observation, such as swelling, blisters, dorsoventral contraction, short and curved worms. In conclusion, our results indicate that potassium usnate represents a possible candidate for a new drug in the control of schistosomiasis.

Short communication: Investigation of extra-intestinal pathogenic Escherichia coli virulence genes, bacterial motility, and multidrug resistance pattern of strains isolated from dairy cows with different severity scores of clinical mastitis.

Escherichia coli is a major pathogen involved in the etiology of environmentally derived bovine mastitis and is characterized by a variety of virulence factors (VF). Mammary infections with E. coli have shown a wide range of clinical signs, causing changes in milk (score 1, or mild), abnormal appearance of milk and udder inflammation (score 2, or moderate), and abnormalities in milk, udder inflammation, and systemic signs of illness (score 3, or severe). Nevertheless, to date, the profile of the genes related to the virulence of the pathogen in mammary infections and the severity scores of cases have not been thoroughly elucidated. Therefore, a panel of 18 virulence-encoding genes associated with extra-enteric pathogenicity of E. coli (ExPEC) were investigated in addition to in vitro swimming and swarming motility profiles and antimicrobial susceptibility/resistance patterns among 114 E. coli strains isolated from cows with clinical mastitis and different severity scores. Of 114 clinical cases, 39.5, 54.4, and 6.1% were mild, moderate, and severe, respectively. The main genes related to VF harbored by isolates were adhesins (fimH 100%; ecpA 64.0%, fimA 31.6%), serum resistance (traT 81.6%; ompT 35.1%), siderophores (irp2 9.6%), and hemolysin (hlyA 7%). Among the isolates studied, 99.1% showed in vitro resistance to bacitracin and cloxacillin, and 98.2% to lincosamin. Of the total isolates, 98.2% were considered multidrug resistant based on the multiple antimicrobial resistance index. No significant difference was observed between mean swimming (13.8 mm) and swarming (13.5 mm) motility, as well as severity scores of clinical mastitis and the ExPEC genes studied. The isolation of strains resistant to various antimicrobials, even though tested only in vitro, highlights the importance of rational use of antimicrobials for mastitis treatment. The high prevalence of the genes related to serum resistance (traT and ompT) and adhesion (ecpA) of the pathogen, in addition to main associations between the genes fimH, ecpA, and traT among cows with severity scores of 1 (15%) and 2 (22.6%), indicates that the genes traT, ecpA, and ompT could be further studied as biomarkers of ExPEC for clinical intramammary infections. In addition, the ExPEC genes ompT (protectin), ibe10 (invasin), and ecpA (adhesin) were investigated for the first time among cows with mastitis, where scores of clinical severity were assessed. Results of this study contribute to the characterization of virulence mechanisms and antimicrobial resistance profile of ExPEC variants that affect dairy cows with different scores of clinical mastitis.

Pyrazoles as Key Scaffolds for the Development of Fluorine-18-Labeled Radiotracers for Positron Emission Tomography (PET).

The need for increasingly personalized medicine solutions (precision medicine) and quality medical treatments, has led to a growing demand and research for image-guided therapeutic solutions. Positron emission tomography (PET) is a powerful imaging technique that can be established using complementary imaging systems and selective imaging agents-chemical probes or radiotracers-which are drugs labeled with a radionuclide, also called radiopharmaceuticals. PET has two complementary purposes: selective imaging for diagnosis and monitoring of disease progression and response to treatment. The development of selective imaging agents is a growing research area, with a high number of diverse drugs, labeled with different radionuclides, being reported nowadays. This review article is focused on the use of pyrazoles as suitable scaffolds for the development of 18F-labeled radiotracers for PET imaging. A brief introduction to PET and pyrazoles, as key scaffolds in medicinal chemistry, is presented, followed by a description of the most important [18F]pyrazole-derived radiotracers (PET tracers) that have been developed in the last 20 years for selective PET imaging, grouped according to their specific targets.

Ionic Liquids and Ohmic Heating in Combination for Pd-catalyzed Cross-coupling Reactions: Sustainable Synthesis of Flavonoids.

In order to meet the increasing demand for environmentally benign chemical processes, we developed a Suzuki-Miyaura reaction protocol based on the combination of ohmic heating (ΩH) and supported ionic liquid phase catalysis (SILPC) in aqueous media. This methodology was applied to the synthesis of a series of flavonoid derivatives, including isoflavones, styrylisoflavones, and diarylalkenylisoflavones.