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The purpose of this study was to determine the apparent prevalence and risk factors of methicillin-resistant Staphylococcus aureus and non-aureus staphylococci and mammaliicocci (NASM) in bulk tank milk (BTM) obtained from 300 dairy farms that belong to a cooperative collecting milk from Indiana, Michigan, and Ohio. Dairy field personnel recorded information about selected farm level risk factors and collected and froze BTM samples (n = 300) that were sent to Michigan State University researchers. Milk samples were thawed at room temperature and pre-enriched by adding 1 to 4 mL of Mueller-Hinton broth supplemented with 6.5% NaCl and incubated at 37°C for 24 h. Subsequently, 10 µL was plated on mannitol salt agar and Mueller-Hinton agar supplemented with 2.5% NaCl containing 2 mg/L oxacillin and 20 mg/L aztreonam. Colonies that grew on the selective media were subcultured on blood agar and identified using MALDI-TOF mass spectrometry. Phenotypic methicillin resistance was tested using cefoxitin disk diffusion. Conventional PCR was used to detect mecA and mecC in phenotypically resistant isolates. Of 550 isolates that were obtained from mannitol salt agar plates and 10 isolates from Mueller-Hinton agar plates, 16 species of NASM accounted for 84% of staphylococci, while S. aureus accounted for the remaining 16%. Among S. aureus, 4 isolates from 4 farms (1.3%) demonstrated phenotypic resistance to methicillin resistance but none carried mecA or mecC genes. Among NASM, 45 isolates from 40 farms (13.3%) demonstrated phenotypic resistance to methicillin. However, only 13 NASM isolates (7 Mammaliicoccus sciuri, 2 Staphylococcus haemolyticus, 1 Mammaliicoccus fleuretti, 1 Staphylococcus epidermidis, 1 Staphylococcus saprophyticus, and 1 Staphylococcus hyicus) from 13 farms were positive for mecA, whereas all were negative for mecC. Thus, the prevalence of mecA-positive NASM in BTM was 4.3%. Based on molecular results, this study demonstrated a low prevalence of methicillin resistance NASM from BTM samples collected from farms in the Upper Midwest. Dairy farms that contained ≤200 lactating cows and had swine located on the farm had a higher prevalence of methicillin-resistant NASM than smaller farms that did not contain swine.

This study aimed to assess (a) the biofilm producer ability and antimicrobial resistance profiles of Staphylococcus (Staph.) aureus and Streptococcus (Strep.) uberis isolated from cows with clinical mastitis (CM) and subclinical mastitis (SCM), and (b) the association between biofilm producer ability and antimicrobial resistance. We isolated a total of 197 Staph. aureus strains (SCM = 111, CM = 86) and 119 Strep. uberis strains (SCM = 15, CM = 104) from milk samples obtained from 316 cows distributed in 24 dairy herds. Biofilm-forming ability was assessed using the microplate method, while antimicrobial susceptibility was determined using the disk diffusion method against 13 antimicrobials. Among the isolates examined, 57.3% of Staph. aureus and 53.8% of Strep. uberis exhibited the ability to produce biofilm, which was categorized as strong, moderate, or weak. In terms of antimicrobial susceptibility, Staph. aureus isolates displayed resistance to penicillin (92.9%), ampicillin (50.8%), and tetracycline (52.7%). Conversely, Strep. uberis isolates exhibited resistance to penicillin (80.6%), oxacillin (80.6%), and tetracycline (37.8%). However, no significant correlation was found between antimicrobial resistance patterns and biofilm formation ability among the isolates.

The objective of this study was to compare the minimum inhibitory concentrations of antimicrobials included in a commercial broth microdilution panel among Gram-positive pathogens that caused non-severe clinical mastitis on three Michigan dairy farms. Duplicate quarter milk samples were collected from eligible quarters of cows enrolled in a randomized clinical trial, cultured in a university laboratory, and identified using MALDI-TOF. Etiologies were grouped by genus as Enterococcus species (n = 11), Lactococcus species (n = 44), non-aureus Staphylococcus species (n = 39), or Streptococcus species (n = 25). Minimum inhibitory concentrations (MICs) were determined using the mastitis panel of a commercially available broth microdilution test. In vitro susceptibility was determined using approved guidelines and included breakpoints for mastitis pathogens, or when not available, breakpoints from other species. Most isolates were inhibited at or below breakpoints that demonstrated in vitro susceptibility. The proportions of susceptible isolates varied among pathogens for pirlimycin, penicillin, and tetracycline. The greatest proportion of resistance was observed for pirlimycin, tetracycline, and sulfadimethoxine. Survival analysis was performed to evaluate differences in MICs among pathogen groups. MIC values varied among pathogens for ceftiofur, cephalothin, erythromycin, penicillin, pirlimycin, and tetracycline. However, nearly all isolates were susceptible to ceftiofur and cephalothin, indicating that pathogen differences in MIC are not likely clinically relevant, as these are the two most commonly administered mastitis treatments in the United States. While differences in vitro susceptibility were observed for some antimicrobials, susceptibility was high to cephalosporin-based IMM treatments that are most commonly used and did not vary among pathogens.

Abstract 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.

The aim of this research was to describe the incidence and treatments of mastitis and other common bovine diseases using one year of retrospective observational data (n = 50,329 cow-lactations) obtained from herd management software of 37 large dairy farms in Wisconsin. Incidence rate (IR) was defined as the number of first cases of each disease divided by the number of lactations per farm. Clinical mastitis (CM) remains the most diagnosed disease of dairy cows. Across all herds, the mean IR (cases per 100 cow-lactations) was 24.4 for clinical mastitis, 14.5 for foot disorders (FD), 11.2 for metritis (ME), 8.6 for ketosis (KE), 7.4 for retained fetal membranes (RFM), 4.5 for diarrhea (DI), 3.1 for displaced abomasum (DA), 2.9 for pneumonia (PN) and 1.9 for milk fever (MF). More than 30% of cows that had first cases of CM, DA, RFM, DI, and FD did not receive antibiotics. Of those treated, more than 50% of cows diagnosed with PN, ME and CM received ceftiofur as a treatment. The IR of mastitis and most other diseases was greater in older cows (parity ≥ 3) during the first 100 days of lactation and these cows were more likely to receive antibiotic treatments (as compared to younger cows diagnosed in later lactation). Cows of first and second parities in early lactation were more likely to remain in the herd after diagnosis of disease, as compared to older cows and cows in later stages of lactation. Most older cows diagnosed with CM in later lactation were culled before completion of the lactation. These results provide baseline data for disease incidence in dairy cows on modern U.S. dairy farms and reinforce the role of mastitis as an important cause of dairy cow morbidity.

We aimed to evaluate the impact of selective dry cow therapy (SDCT) (protocol 1: antimicrobial combined with internal teat sealant (ITS); vs. protocol 2: ITS alone) on bacterial diversity and the abundance of quarter milk. Eighty high production cows (parity ≤ 3 and an average milk yield of 36.5 kg/cow/day) from the largest Brazilian dairy herd available were randomly selected; milk quarter samples were collected for microbiological culture (MC) on the day of drying-off (n = 313) and on day 7 post-calving (n = 313). Based on the results of the MC before and after calving, 240 quarters out of 313 were considered healthy, 38 were cured, 29 showed new infections and 6 had persistent infections. Mammary quarters were randomly selected based on intramammary information status and SDCT protocols for bacterial diversity analyses. The bacterial diversity was similar when comparing both healthy and cured quarters submitted to both drying-off protocols. Despite healthy cows that were treated at dry-off using only teat sealant showing no alteration in the alpha and beta bacterial diversity, they did show a higher abundance of bacterial groups that may be beneficial to or commensals of the mammary gland, which implies that antibiotic therapy should be reserved for mammary quarters with a history of mastitis.

Abstract Lipases are hydrolases used in various sectors such as the food, pharmaceutical and chemical synthesis industries. In this study, epiphytic microorganisms were isolated from the Serra of Ouro Branco State Park (Minas Gerais, Brazil) and were subsequently evaluated for their ability to produce extracellular lipases. Among the 46 isolated strains, 25 presented positive results for lipase production in the agar plate screening assay. Two of these strains that expressed the highest diffusion halos, were genetically identified as Serratia marcescens and Pseudomonas fluorescens and catalogued in the Tropical Cultures Collection from the André Tosello Foundation/Brazil as CCT 7796 and CCT 7797, respectively. The fermentation growth kinetics indicated that the maximum extracellular lipase activities were achieved between 96 and 120h of cultivation. The highest lipolytic activity for both strains was observed at an optimum temperature and pH of 37°C and 7.0, respectively. At these conditions, the lipase activity detected in the crude enzymatic extract of both strains was close to 15.0 U/mL. We consider that these species are promising lipase producers for industrial applications.

A multi-step cascade strategy using integrated ligand- and target-based virtual screening methods was developed to select a small number of compounds from the ZINC database to be evaluated for trypanocidal activity. Winnowing the database to 23 selected co

Background: The malaria burden remains a major public health concern, especially in sub-Saharan Africa. The complex biology of Plasmodium, the apicomplexan parasite responsible for this disease, challenges efforts to develop new strategies to control the d

Background: A pathophysiological link exists between dysregulation of MEF2C transcription factors and heart failure (HF), but the underlying mechanisms remain elusive. Alternative splicing of MEF2C exons α, β and γ provides transcript diversity with gene activation or repression functionalities. Methods: Neonatal and adult rat ventricular myocytes were used to overexpress MEF2C splicing variants γ+ (repressor) or γ-, or the inactive MEF2Cγ+23/24 (K23T/R24L). Phenotypic alterations in cardiomyocytes were determined by confocal and electron microscopy, flow cytometry and DNA microarray. We used transgenic mice with cardiac-specific overexpression of MEF2Cγ+ or MEF2Cγ− to explore the impact of MEF2C variants in cardiac phenotype. Samples of non-infarcted areas of the left ventricle from patients and mouse model of myocardial infarction were used to detect the expression of MEF2Cγ+ in failing hearts. Findings: We demonstrate a previously unrealized upregulation of the transrepressor MEF2Cγ+ isoform in human and mouse failing hearts. We show that adenovirus-mediated overexpression of MEF2Cγ+ downregulates multiple MEF2-target genes, and drives incomplete cell-cycle reentry, partial dedifferentiation and apoptosis in the neonatal and adult rat. None of these changes was observed in cardiomyocytes overexpressing MEF2Cγ-. Transgenic mice overexpressing MEF2Cγ+, but not the MEF2Cγ-, developed dilated cardiomyopathy, correlated to cell-cycle reentry and apoptosis of cardiomyocytes. Interpretation: Our results provide a mechanistic link between MEF2Cγ+ and deleterious abnormalities in cardiomyocytes, supporting the notion that splicing dysregulation in MEF2C towards the selection of the MEF2Cγ+ variant contributes to the pathogenesis of HF by promoting cardiomyocyte dropout. Funding: São Paulo Research Foundation (FAPESP); Brazilian National Research Council (CNPq). Keywords: MEF2, Splicing, Heart failure, Dedifferentiation, Cell cycle re-entry, Cardiomyocyte, Sarcomere disassembly

This compilation is the result of identification of material recently collected from Southern Brazil. Forty-one new records of Phoridae are recorded for the state of Rio Grande do Sul, and the species Eibsfeldtphora cumsaltensis Disney 2009, Megaselia (M.) gracilipalpis Borgmeier 1969, Megaselia (Aphiochaeta) latimanus (Malloch, 1914), Melaloncha curvata Brown, 2005, and Trophodeinus vicinus (Borgmeier, 1963) are recorded for the first time in Brazil. Species are distributed in 18 genera and 3 subfamilies. The total known diversity of phorids in the state is augmented from 10 to 51 species. An updated distribution for Brazil is presented for each species.