Virulence factors and antimicrobial resistance of Staphylococcus aureus isolated from the production process of Minas artisanal cheese from the region of Campo das Vertentes, Brazil.

Staphylococcus aureus is one of the main pathogens found in cheeses produced with raw milk, including Minas artisanal cheese from Brazil. However, information about S. aureus isolated from artisanal cheeses and its sources of production in small-scale dairies is very limited. We aimed to characterize the virulence factors of S. aureus isolated from raw milk, endogenous starter culture, Minas artisanal cheese, and cheese handlers from the region of Campo das Vertentes, Minas Gerais, Brazil. We identified the staphylococcal isolates by MALDI-TOF mass spectrometry. We evaluated biofilm production on Congo red agar and polystyrene plates. We used PCR to detect icaA, icaB, icaC, sea, seb, sec, sed, see, tsst-1, agr, and mecA. We evaluated the expression of staphylococcal toxin genes in PCR-positive staphylococcal isolates using quantitative reverse-transcription PCR, and we evaluated the production of these toxins and their hemolytic activity in vitro. We also evaluated the antimicrobial resistance profile of the staphylococcal isolates. For statistical analysis, we used cluster analysis, χ2 tests, and correspondence tests. We analyzed 76 staphylococcal isolates. According to PCR, 18.42, 18.42, 2.63, and 77.63% were positive for sea, tsst-1, sec, and agr, respectively. We found low expression of staphylococcal toxin genes according to quantitative reverse-transcription PCR, and only 2 staphylococcal isolates produced toxic shock syndrome toxins. A total of 43 staphylococcal isolates (56.58%) had hemolytic activity; 53 were biofilm-forming on Congo red agar (69.73%), and 62 on polystyrene plates (81.58%). None of the staphylococcal isolates expressed the mecA gene, and none presented a multi-drug resistance pattern. The highest resistance was observed for penicillin G (67.11%) in 51 isolates and for tetracycline (27.63%) in 21 isolates. The staphylococcal isolates we evaluated had toxigenic potential, with a higher prevalence of sea and tsst-1. Biofilm production was the main virulence factor of the studied bacteria. Six clusters were formed whose distribution frequencies differed for hemolytic activity, biofilm formation (qualitative and quantitative analyses), and resistance to penicillin, tetracycline, and erythromycin. These findings emphasize the need for effective measures to prevent staphylococcal food poisoning by limiting S. aureus growth and enterotoxin formation throughout the food production chain and the final product.

Increased illness burden in women with comorbid bipolar and premenstrual dysphoric disorder: data from 1 099 women from STEP-BD study.

BACKGROUND: The impact of comorbid premenstrual dysphoric disorder (PMDD) in women with bipolar disorder (BD) is largely unknown. AIMS: We compared illness characteristics and female-specific mental health problems between women with BD with and without PMDD. MATERIALS & METHODS: A total of 1 099 women with BD who participated in the Systematic Treatment Enhancement Program for Bipolar Disorder (STEP-BD) were studied. Psychiatric diagnoses and illness characteristics were assessed using the Mini International Neuropsychiatric Interview. Female-specific mental health was assessed using a self-report questionnaire developed for STEP-BD. PMDD diagnosis was based on DSM-5 criteria. RESULTS: Women with comorbid BD and PMDD had an earlier onset of bipolar illness (P < 0.001) and higher rates of rapid cycling (P = 0.039), and increased number of past-year hypo/manic (P = 0.003), and lifetime/past-year depressive episodes (P < 0.05). Comorbid PMDD was also associated with higher proportion of panic disorder, post-traumatic stress disorder, generalized anxiety disorder, bulimia nervosa, substance abuse, and adult attention deficit disorder (all P < 0.05). There was a closer gap between BD onset and age of menarche in women with comorbid PMDD (P = 0.003). Women with comorbid PMDD reported more severe mood symptoms during the perinatal period and while taking oral contraceptives (P < 0.001). DISCUSSION: The results from this study is consistent with research suggesting that sensitivity to endogenous hormones may impact the onset and the clinical course of BD. CONCLUSIONS: The comorbidity between PMDD and BD is associated with worse clinical outcomes and increased illness burden.

Biofilm and toxin profile: A phenotypic and genotypic characterization of coagulase-negative staphylococci isolated from human bloodstream infections.

Coagulase-negative staphylococci (CNS) represent one of the most prevalent microorganisms in nosocomial infections worldwide, nevertheless little is known about their pathogenicity features. Thus, our aim was to characterize virulence aspects of CNS isolated from patients with bloodstream infections assisted in hospitals of Belo Horizonte, MG, Brazil. Strains were identified using bioMérieuxVitek® and for biofilm production evaluation, Congo Red Agar (CRA) and polystyrene plates were used. PCR was applied to detect icaA, icaB, icaC, atlE, sea, sec, sed, tsst-1 and agr. For statistical analyses were used hierarchical cluster, chi-square test and correspondence. 59 strains were analyzed, being S. haemolyticus the most prevalent. On CRA, 96.5% were biofilm producer, whereas on polystyrene plate, 100% showed adhesion at different times evaluated. Regarding genotypic analyses, 15.2%, 38.9%, 8.4%, 49.1%, 76.2%, 23.7%, 1.6%, 30.5% and 38.9% were positive for icaA, icaB, icaC, atlE, sea, sec, sed, tsst-1 and agr, respectively. Six clusters were formed and frequency distributions of agr, atlE, icaA, icaB, sea, sec, tsst-1 differed (P < 0.001). In conclusion, all strains were biofilm producer, with high prevalence of atlE, and had potential of toxin production, with high prevalence of sea. According to the group-analyses, icaB showed relationship with the strong adherence in samples.

Brazilian Pampa Biome Honey Protects Against Mortality, Locomotor Deficits and Oxidative Stress Induced by Hypoxia/Reperfusion in Adult Drosophila melanogaster.

We aimed to investigate the potential beneficial effects of the Brazilian Pampa biome honey in a Drosophila-based hypoxia model. Adult flies were reared in standard medium in the presence or absence of honey (at a final concentration of 10 % in medium). Then, control flies (4 % sucrose in medium) and honey-treated flies were submitted to hypoxia. Subsequently, flies were analyzed for mortality, neurolocomotor behavior (negative geotaxis), mitochondrial/oxidative stress parameters and expression of hypoxia/stress related genes by RT-qPCR. The HPLC analysis revealed the presence of phenolics and flavonoids in the studied honey. Caffeic acid was the major compound followed by p-coumaric acid and kaempferol. The presence of such compounds was correlated with a substantial antioxidant activity in vitro. Flies subjected to hypoxia presented marked mortality, locomotor deficits and changes in oxidative stress and mitochondrial activity parameters. Honey treatment was able to completely block mortality and locomotor phenotypes. In addition, honey was able to reverse ROS production and hypoxia-induced changes in mitochondrial complex I and II activity. Hypoxia also induced an up-regulation in mRNA expression of Sima (HIF-1), NFκß, NRF2, HOX, AKT-1, InR, dILP2, dILP5 and HSP27. Honey treatment was not able to modulate changes in the tested genes, indicating that its protective effects involve additional mechanisms other than transcriptional activity of hypoxia-driven adaptive responses in flies. Our results demonstrated, for the first time, the beneficial effects of honey against the deleterious effects of hypoxia/reperfusion processes in a complex organism.

Utilization of macrominerals and trace elements in pregnant heifers with distinct feed efficiencies.

The objective of the study was to evaluate utilization of dietary minerals and trace elements in pregnant heifers with distinct residual feed intakes (RFI). Feed intake, body weight (BW), and body composition traits were recorded in 36 crossbred heifers over a period of 37 wk, starting shortly after weaning at 8.3 (0.10; standard deviation) mo of age with an average BW of 276 (7.8) kg. Both BW and body composition were monitored regularly throughout the study, whereas individual feed intake was assessed during the last 84 d of the trial. Data recorded were used to calculate RFI for each heifer. Heifers were ranked based on RFI and assigned to high (n=14) or low (n=10) RFI groups. After the RFI study, 24 selected heifers [age 18.2 (0.14) mo; 87.5 (4.74) d in gestation; 497 (8.5) kg of BW] were used in an indirect digestibility trial (lignin as internal marker). Heifers were fed a ration containing corn silage, haylage, and a mineral premix in which Ca, P, K, Na, Mg, S, Cu, Fe, Mn, Mo, Se, Zn, and Co were provided in the diet according to National Research Council requirements of pregnant replacement heifers. The digestibility trial lasted 1 wk, during which samples of feces were gathered twice daily, and blood and liver biopsy samples were collected on the last day. We noted no significant differences between low- and high-RFI heifers in dry matter digestibility. Apparent absorption of Cu, Zn, and Mn was increased in heifers with low RFI, and apparent absorption of Co tended to be greater for these animals. Concentrations of macrominerals and trace elements in serum of pregnant heifers were similar for both groups except for Se, which was increased in the serum of low-RFI heifers. Liver concentrations of Cu, Fe, Mn, Mo, Se, and Zn did not differ between low- and high-RFI heifers. In conclusion, whereas improved absorption of some trace elements (Cu, Zn, Mn, and Co) and increased Se serum concentration appear to be associated with superior feed efficiency in pregnant heifers, further studies are needed to investigate the causality of such relationships.

Culturable bacterial diversity from a feed water of a reverse osmosis system, evaluation of biofilm formation and biocontrol using phages.

Biofilm formation on reverse osmosis (RO) systems represents a drawback in the application of this technology by different industries, including oil refineries. In RO systems the feed water maybe a source of microbial contamination and thus contributes for the formation of biofilm and consequent biofouling. In this study the planktonic culturable bacterial community was characterized from a feed water of a RO system and their capacities were evaluated to form biofilm in vitro. Bacterial motility and biofilm control were also analysed using phages. As results, diverse Protobacteria, Actinobacteria and Bacteroidetes were identified. Alphaproteobacteria was the predominant group and Brevundimonas, Pseudomonas and Mycobacterium the most abundant genera. Among the 30 isolates, 11 showed at least one type of motility and 11 were classified as good biofilm formers. Additionally, the influence of non-specific bacteriophage in the bacterial biofilms formed in vitro was investigated by action of phages enzymes or phage infection. The vB_AspP-UFV1 (Podoviridae) interfered in biofilm formation of most tested bacteria and may represent a good alternative in biofilm control. These findings provide important information about the bacterial community from the feed water of a RO system that may be used for the development of strategies for biofilm prevention and control in such systems.

Potential of coffee straw biochal as a substrate conditioner in seed lettuce and sorghum germination and vigority.

The use of residues from coffee production to obtain biochar is a sustainable approach, which aims to minimize the environmental impact of these materials. In this study, the effect of adding coffee straw biochar on the physiological quality of lettuce and sorghum seeds was investigated. Thus, the objective of this work was to study the effect of adding different concentrations of coffee biochar in the substrate composition on the physiological quality of lettuce (Lactuca sativa) and sorghum (Sorghum bicolor) seeds. The experimental design used was completely randomized, with five concentrations of biochar (0; 7.5; 15; 30 and 60%), conducted with four replications of 25 seeds. The use of biochar in the concentrations studied does not provide an increase in the average germination percentage and vigor of lettuce and sorghum seeds. The increase in the concentration of biochar caused less seed vigor, suggesting a toxic effect. For seed germination, there was no significant difference between lettuce and sorghum species, regardless of treatment. For the germination speed index, sorghum seeds have higher means, except for the treatment with the addition of 15% coffee straw biochar. Lettuce seeds have higher shoot length averages, except for treatment with 100% commercial substrate. The sorghum seeds have higher mean root length and dry mass than lettuce, regardless of the treatment.

Molecular characterization of a new lytic bacteriophage isolated from cheese whey.

In this study, we isolated and characterized a lytic Lactococcus lactis bacteriophage from the sera of a failed fermentation. The phage was isolated and cultured in L. lactis subsp. cremoris in M17 medium. The isolated bacteriophage was characterized by multiplex PCR, pulsed-field electrophoresis, DNA restriction digestion, analysis of the N-terminal sequence of the phage major structural protein, transmission electron microscopy and sequencing and analysis of a conserved fragment of its genome. Analysis of the viral genome indicates that its genome is composed of a DNA strand of approximately 48 kb in length, and PCR and microscopy confirmed that IL-P1 belongs to the group of 936-type phages in the family Siphoviridae, which is the most abundant type of lactococcal virus in dairy products worldwide. To our knowledge, this is the first report of a virus within this family that has a presumptive genome larger than 40 kb.

Stepwise disproportionation in polyelectrolyte complexes.

Structural properties and the topology of polyelectrolyte complexes (PECs) formed in solution have been investigated under different conditions by Monte Carlo simulations using a coarse-grained model. The extension of individual polyions has been characterized by their radius of gyration, whereas the composition of the complexes has been investigated by their net charge and their internal topological structure by a novel analysis describing how the shorter polycations link to monomers of the longer polyanion. Conditions have been found at which the polyanion and a given number of polycations form distinguishable complexes differing in (i) the polyanion conformation and (ii) the fraction of polycations being in extended and collapsed states. Thus, at equilibrium, these PECs display a stepwise variation of the degree of intrachain disproportionation within the polyanion (also referred to as intrachain segregation), concomitant with the interchain disproportionation of the polycations, which is in agreement with previous theoretical predictions. The coexistence of the different polyelectrolyte complex structures appears, generally, at mixing ratios close to but different from charge equivalence and, as a consequence, broad polyelectrolyte size distributions are commonly obtained.

Polyelectrolyte compaction by pH-responsive agents.

Compaction of negatively charged polyanions by polycations with different characteristics is investigated using Monte Carlo simulation in a coarse-grain model. Two different routes are tested and the results compared. In one, the polycation/polyanion charge ratio is varied by increasing the amount of polycations, keeping all the chain characteristics constant. In the other, the linear charge density of the polycations is altered but their number is kept constant. The set of systems in which the linear charge density changes is used as a model for a system comprising chains with different degrees of ionization under different pH conditions. In both cases, polycation/polyanion charge ratios ranging from 0.25 to 1.25 are addressed. The system with unitary charge ratio is common to both routes. It is seen that, although the overall trends followed by the two sets of systems are similar, marked differences can be discerned both for low charge ratios, and for the higher ones, where the systems are overcharged. Coexistence regimes are clearly detected in some of the systems. The results obtained computationally can be used to guide practical applications.

Severe fetal hydrocephalus with and without neural tube defect: a comparative study.

OBJECTIVE: To describe the main perinatal and 1-year outcomes in babies with a prenatal ultrasonographic diagnosis of severe hydrocephalus according to the presence or absence of a neural tube defect (NTD) in a country where abortion is illegal. METHOD: The study population consisted of cases referred to and delivered at Hospital de Clínicas de Porto Alegre, diagnosed between January 1993 and December 2001. The diagnosis of severe hydrocephalus was based on a lateral ventricular atrium diameter > or =15 mm in at least one hemisphere. RESULTS: Sixty cases were ascertained: 28 with NTD (group 1) and 32 without NTD (group 2). The groups were similar in terms of maternal and child variables at birth and hospitalization days during the 1st year of life. The mortality (including intrauterine deaths and deaths of babies with malformations incompatible with life that characterize a very poor prognosis) until 1 year of age was 36% in group 1 and 59% in group 2 (p = 0.077). The rate of cardiac malformations was higher in the group without NTD (p = 0.015). The length of hospital stay after birth (1st admission) was significantly higher in the group with NTD (p = 0.007). CONCLUSIONS: The morbidity was higher in the group with NTD, possibly due to the higher number of surgical interventions in the central nervous system. However, the mortality was higher in the group without NTD, possibly due to the presence of other associated malformations, especially congenital heart disease. Further studies should focus on neurological function and quality of life of the children and their families at the end of the 1st year and after 2 or 6 years of age.

Polyion adsorption onto catanionic surfaces. A Monte Carlo study.

The adsorption of a single and negatively charged polyion with varying flexibility onto a surface carrying both negative and positive charges representing a charged membrane surface has been investigated by using a simple model employing Monte Carlo simulations. The polyion was represented by a sequence of negatively charged hard spheres connected with harmonic bonds. The charged surface groups were also represented by charged hard spheres, and they were positioned on a hard surface slightly protruding into the solution. The surface charges were either frozen in a liquidlike structure or laterally mobile. With a large excess of positive surface charges, the classical picture of a strongly adsorbed polyion with an extended and flat configuration emerged. However, adsorption also appeared at a net neutral surface or at a weakly negatively charged surface, and at these conditions the adsorption was stronger with a flexible polyion as compared to a semiflexible one, two features not appearing in simpler models containing homogeneously charged surfaces. The presence of charged surface patches (frozen surface charges) and the ability of polarization of the surface charges (mobile surface charges) are the main reasons for the enhanced adsorption. The stronger adsorption with the flexible chain is caused by its greater ability to spatially correlate with the surface charges.

Antagonism against Vibrio cholerae by diffusible substances produced by bacterial components of the human faecal microbiota.

Cholera vibrios sometimes survive, probably in low-level silent populations, in the small intestine of chronic carriers or pass through the gastrointestinal tract of a few individuals without causing diarrhoea or colonisation. To understand these situations, the present study used plate cultures (ex-vivo test) to investigate the frequency of appearance of an inhibitory halo against Vibrio cholerae produced by faecal specimens from 92 healthy volunteers (40 females, 52 males) aged 4-61 years. The frequency of inhibitory halo was 20.6% in the whole group. An apparently higher percentage (27.3%) was observed in the age range 20-40 years when compared with the range 4-19 years (10.7%), but not the range 41-61 years (20.0%). Frequency was significantly higher in males (30.8%) than females (7.5%). The dominant microbiota of a volunteer whose faeces produced an inhibitory halo was isolated by plate culture of decimal dilutions in an anaerobic chamber. Potential isolates of 26 apparently different morphologies were associated with germ-free NIH mice. One week later, the inhibitory test showed an antagonistic halo around the faeces from the associated animals, but not from the axenic mice. Of the 26 bacteria isolated, two (Lactobacillus sp. and Peptostreptococcus sp.) produced a compound antagonistic against V. cholerae in an in-vitro assay. When bi-associated with germ-free mice those strains eliminated the vibrio from the intestinal ecosystem in c. 5 days.

Social disability of Brazilian mood disorder patients.

Mood disorders cause many social problems, often involving family relationships. Few studies are available in the literature comparing patients with bipolar, unipolar, dysthymic, and double depressive disorders concerning these aspects. In the present study, demographic and disease data were collected using a specifically prepared questionnaire. Social adjustment was assessed using the Disability Adjustment Scale and family relationships were evaluated using the Global Assessment of Relational Functioning Scale. One hundred patients under treatment for at least 6 months were evaluated at the Psychiatric Outpatient Clinic of the Botucatu School of Medicine, UNESP. Most patients were women (82%) more than 50 (49%) years old with at least two years of follow-up, with little schooling (62% had less than 4 years), and of low socioeconomic level. Logistic regression analysis showed that a diagnosis of unipolar disorder (P = 0.003, OR = 0.075, CI = 0.014-0.403) and dysthymia (P = 0.001, OR = 0.040, CI = 0.006-0.275) as well as family relationships (P = 0.002, OR = 0.953, CI = 0914-0.992) played a significant role in social adjustment. Unipolar and dysthymic patients presented better social adjustment than bipolar and double depressive patients (P < 0.001), results that were not due to social class. These patients, treated at a teaching hospital, may represent the severest mood disorder cases. Evaluations were made knowing the diagnosis of the patients, which might also have influenced some of the results. Social disabilities among mood disorder patients are very frequent and intensive.

Protective effect of Saccharomyces boulardii against the cholera toxin in rats.

The effect of orogastric administration of Saccharomyces boulardii on the anatomopathological aspect of the jejunal villi was studied in male Fischer rats (weighing about 40 g) orogastrically infected with a culture of Vibrio cholerae. Experimental and control groups received lyophilized S. boulardii (25 mg suspended in 0.5 ml saline) or 0.5 ml saline, respectively, three times a day for 10 days by gastric intubation. On day 5 of treatment, 0.5 ml of a culture of V. cholerae containing 10(8) viable cells was inoculated by gastric intubation into both groups. Histopathological examination of the jejunal mucosa showed extensive lesions of the superficial epithelium of the villi from the control group whereas few lesions of this superficial epithelium were observed in the experimental group. These data show that the inhibition of the action of the cholera toxin on enterocytes by S. boulardii suggested by recent results in vitro can be demonstrated in vivo.

Relation of cervical length at 22-24 weeks of gestation to demographic characteristics and obstetric history.

Preterm delivery is the main cause of neonatal death and ultrasonographic cervical assessment has been shown to be more accurate than digital examination in recognizing a short cervix. This is a cross-sectional study, involving 1131 women at 22-24 weeks of pregnancy, designed to determine the distribution of cervical length and to examine which variables of demographic characteristics and obstetric history increase the risk of a short cervix (15 mm or less). The distribution of maternal demographic and obstetric history characteristics among patients with cervical length pound 15 mm was analyzed and compared to the findings for the general population. Risk ratios (RR) between subgroups were generated from this comparison. Median cervical length was 37 mm and in 1.5% of cases it was 15 mm or less. The proportion of women with a short cervix (< or =15 mm) was significantly higher among patients with a low body mass index (RR = 3.5) and in those with previous fetal losses between 16-23 weeks (RR = 33.1) or spontaneous preterm deliveries between 24-32 weeks (RR = 14.1). We suggest that transvaginal sonographic measurement of cervical length be performed as part of a routine midtrimester ultrasound evaluation. There are specific variables of demographic characteristics and obstetric history which increase the risk of detecting a short cervix at 22-24 weeks.

Synthesis and biological activity of new potential antimalarial: 1H-pyrazolo[3,4-b]pyridine derivatives.

The appearance of drug resistant Plasmodium falciparum malaria necessitates the search for novel antimalarial agents. Using the classical ring-bioisosterism concept as a strategy to develop new potential drugs, 1H-pyrazolo[3,4-b]pyridine 4-aminomethanol compounds were designed and synthesized as isosteres of the classical quinoline antimalarial mefloquine. The hydrochloride form of these compounds were tested for in vitro antimalarial activity against chloroquine-sensitive (Sierra Leone D-6) and resistant (Indochina W-2) clones of P. falciparum. The results described herein indicated that 1-H-pyrazolo[3,4-b]pyridine system represents a bioisosteric framework to quinoline system in the antimalarial activity.

A meta-analysis of the effects of dietary copper, molybdenum, and sulfur on plasma and liver copper, weight gain, and feed conversion in growing-finishing cattle.

The minerals Cu, Mo, and S are essential for metabolic functions related to cattle health and performance. The interaction between Cu, Mo, and S can determine the utilization of each mineral, in particular Cu, by ruminants. A meta-analysis was performed to evaluate the effects of dietary Cu, Mo, and S and their interactions on plasma and liver Cu, ADG, and G:F in growing-finishing cattle. Data were collated from 12 published studies. The model with the best fit to data indicated plasma Cu was positively affected by dietary Cu (P < 0.01) and negatively affected by both dietary Mo (P < 0.01) and S (P < 0.01). Another model also indicated that plasma Cu concentration is positively related to Cu:Mo ratio in the diet (P < 0.01). Dietary Cu had a positive effect on liver Cu (P < 0.01), whereas Mo showed a negative effect (P < 0.05), and no effect of dietary S on liver Cu was observed (P > 0.05). Average daily gain was negatively affected by dietary Mo (P < 0.05) and S (P < 0.01) and positively affected by Cu:Mo ratio (P < 0.01), likely because an increased Cu:Mo ratio minimizes the antagonistic effect of Mo on Cu. The feed conversion ratio was negatively affected by Mo (P < 0.05) and S (P < 0.01), whereas effects of the Cu:Mo ratio and dietary Cu were not significant (P > 0.05). The interaction between S and Mo affected (P < 0.01) G:F, which was likely related to a positive response with the proper balance between these minerals. In conclusion, dietary Cu, Mo, and S and the Cu:Mo ratio caused changes in plasma Cu. Only dietary Mo and S led to a negative response in the performance of growing-finishing cattle, whereas the diet Cu:Mo ratio has a linear and quadratic effect on ADG. Nutritionists and producers need to consider with caution the supplementation of growing-finishing cattle diets with Mo and S because of their potentially adverse effects on animal performance. An appropriate Cu:Mo ratio is desirable to minimize the effects of an impaired supply of Mo on Cu metabolism and ADG.

Use of phages against antibiotic-resistant Staphylococcus aureus isolated from bovine mastitis.

Bovine mastitis is the primary disease of dairy cattle worldwide and it causes large economic losses. Among several microorganisms that are the causative agents of this disease, Staphylococcus aureus is the most prevalent. Although antibiotic therapy is still the most widely used procedure for the treatment of bovine mastitis, alternative means of treatment are necessary due to the presence of antibiotic residues in milk, which is a growing concern because of its interference with the production of milk derivatives and the selection of resistant bacterial strains. The use of bacteriophages as a tool for the control of pathogens is an alternative treatment to antibiotic therapy. In this work, to obtain phages with the potential for use in phage therapy as a treatment for mastitis, we isolated and identified the bacteria from the milk of mastitis-positive cows. A total of 19% of the animals from small and medium farms of the Zona da Mata Mineira, Brazil, was positive for bovine mastitis, and bacteria of the genus Staphylococcus were the most prevalent pathogens. The majority of the S. aureus isolates tested was resistant to penicillin and ampicillin. In parallel, we isolated 10 bacteriophages able to infect some of these S. aureus isolates. We determined that these phages contained DNA genomes of approximately 175 kb in length, and the protein profiles indicated the presence of 4 major proteins. Electron microscopy revealed that the phages are caudate and belong to the Myoviridae family. The isolates exhibited interesting features for their use in phage therapy such as a high lytic potential, a wide range of hosts, and thermostability, all of which favor their use in the field.

Relationships between chewing behavior, digestibility, and digesta passage kinetics in steers fed oat hay at restricted and ad libitum intakes.

The objective of this study was to evaluate the relationships between chewing behavior, digestibility, and digesta passage kinetics in steers fed oat hay at restricted and ad libitum intakes. Four Hereford steers, with an initial average BW of 136 kg, were used in an experiment conducted as a balanced 4 × 4 Latin square with 4 treatments (levels of intake) and 4 periods. Animals were fed lopsided oat hay (Avena strigosa Schreb.) at 4 levels of intake (as a percentage of BW): 1.5, 2.0, 2.5, and ad libitum. Digestibility, chewing behavior, and digesta passage kinetic measurements were recorded during the experimental period. Chewing rates during eating and ruminating [(chews•min(-1))/g of DMI•kg(-1) of BW•d(-1)] decreased (P = 0.018 and P = 0.032, respectively) with increased DMI (g•kg(-1) of BW•d(-1)), whereas total chewing and total time spent on each chewing activity increased. Calculated total energy expended by the chewing activity was 4.2, 4.4, 5.2, and 5.3% of ME intake for DMI of 1.5, 2.0, and 2.5% of BW and ad libitum, respectively, indicating that adjustments in animal chewing behavior may be a mechanism of reducing energy expenditure when forages are fed at restricted intake. Hay digestibility decreased (P < 0.001) with increased DMI (r = -0.865). Digesta mean retention time (h) was strongly correlated with DMI (r = -0.868) and OM digestibility (r = 0.844). At reduced intake, hay digestibility was enhanced (P < 0.001) by extending digesta retention time and by increasing chewing efficiency, highlighting the relationship between chewing behavior and the digestive process. Fractional outflow rate of particulate matter from the reticulorumen (k(1)) was positively correlated with total chews, emphasizing that the decrease in particle size caused by chewing facilitates particle flow through the digestive tract. Increased hay intake also increased (P < 0.001) k(1), whereas passage rate of the liquid phase, transit time, and rumen fill were not affected (P > 0.05). The latter was correlated with rumen volume (r = 0.803). In conclusion, the results of this study indicate that animals fed at restricted intake increased chewing rate when eating and ruminating, which, along with a longer digesta retention time, contributed to enhance feed digestibility.