Milton Ricardo Azedo

Perfil celular e microbiológico do leite de ovelhas Santa Inês no período lactante e pós-desmame

The aim was to evaluate and compare the microbiological and cellular profile of the milk of Santa Ines ewes during the lactation period and the active involution. Milk samples were analyzed from 12 ewes during these distinct periods. Clinical examination of the mammary gland, somatic cell count (SCC), California Mastitis Test (CMT), bacteriologic screening and sensibility of the pathogens in vitro were performed. Most alterations were observed in the active involution period. SCC and CMT were higher in this same period. Besides this, a high persistency of infection occurred. The active involution period did not show high susceptibility. Coagulase-negative staphylococci were the only isolated bacteria. A high antimicrobial sensibility of these pathogens was also encountered.

Lactation stage and udder health status of Santa Ines ewes

Avaliou-se o risco de infeccao em diferentes fases da lactacao em 33 ovelhas da raca Santa Ines. Inicialmente a glândula foi submetida ao exame fisico e a prova de fundo escuro. Posteriormente, amostras de leite foram coletadas assepticamente para a realizacao de exame bacteriologico - California Mastitis teste -, e contagens microscopica e automatica de celulas somaticas. Nenhuma diferenca foi observada entre as distintas fases de lactacao. Observou-se alta persistencia de infeccoes intramamarias, e tendencia a maior contagem de celulas somaticas no ultimo periodo de lactacao, que pode ser oriunda da maior resistencia a infeccoes neste periodo.

Antimicrobial susceptibility of coagulase-negative staphylococci isolated from meat-producing ewes with mastitis

Avaliou-se a sensibilidade antimicrobiana in vitro de 121 cepas de estafilococos coagulase-negativa isolada de leite de ovelhas Santa Ines, aos farmacos: penicilina, amoxicilina, ampicilina, estreptomicina, oxaciclina, neomicina, cefalotina, gentamicina e sulfonamida. A resistencia a sulfonamida foi a mais frequente (27,3%), seguida pela estreptomicina (14,0%) e pela oxaciclina (14,0%), enquanto da gentamicina (1,6%) foi a menos frequente. Todas as cepas foram sensiveis a pelo menos um antimicrobiano, e 20,3% das cepas apresentaram resistencia multipla. Os resultados mostram a importância de Staphylococci coagulase-negativas como agentes causadores de mastite em ovinos, e o perfil de resistencia multipla indica a importância da determinacao da resistencia a oxaciclina como indicador da presenca de ilhas de patogenicidade que contem fatores de virulencia e resistencia a outros antimicrobianos que contribuem para a sobrevivencia da bacteria ao tratamento.

Viabilidade celular, fagocitose e espraiamento de fagócitos mononucleares, e liberação de peróxido de hidrogênio por leucócitos de glândulas mamárias bovinas sadias e infectadas

The study aimed to evaluate the cell viability, the phagocytosis and spreading rates by the mononuclear phagocytes, and hydrogen peroxide (H2O2) release by leukocytes from healthy and infected mammary glands. Thus, 94 milk samples were divided according the results of the bacteriological analysis and the somatic cell count (SCC). No significant difference was found in cell viability, the phagocytosis and spreading rates by mononuclear phagocytes between the distinct groups. Therefore, the H2O2 release by leukocytes was higher in the milk samples from healthy mammary glands compared to those infected with Streptococcus spp. or Corynebacterium spp. However, when the H2O2 release by phagocytes in 1mL of milk according to SCC mL-1 of each sample was estimated, it was found that milk samples from infected, infected with Staphylococcus spp. and bacteriological negative quarters with high SCC were higher than the healthy ones. It was also observed a positive correlation among SCC and cell viability or phagocytosis and spreading rates, and a negative correlation between H2O2 release and cell viability or SCC. In face of, it can be concluded that the SCC, as well as their function and the cell viability, are related to mammary gland health.

Avaliação funcional de monócitos de bovinos naturalmente infectados pelo vírus da leucose bovina

Assuming that the bovine leukosis virus (BLV) alters quantitatively and qualitatively bovine circulating leukocyte subpopulations, thus influencing the innate immune response, monocytes function in BLV-infected cattle was assessed. Peripheral blood was obtained from 10 BLV-negative cows (SN), 10 naturally BLV-infected, non-lymphocytotic cows (AL), and 10 BLV-infected cows with persistent lymphocytosis (PL). Monocytes were isolated by density gradient and adherence to plates. Cells were submitted to Trypan Blue dye exclusion viability assay, phagocytosis of Zymosan and cell-spreading assays, and quantification of hydrogen peroxide (H2O2) and nitric oxide (NO) production. Monocytes from cattle with PL had the lowest viability (P<0.001), phagocytosis of Zymosan particles (P<0.001), and spreading (P=0.006) rates. Additionally, monocytes from cows with PL had the highest production of H2O2 , with no prior stimulus (P=0.001), and after in vitro stimulus with phorbol 12-myristate 13-acetate (P=0.006). Nonetheless, the boost in H 2 O 2 production, provided by in vitro stimulus, observed in monocytes from cows with PL was lower (P=0.015) than that observed in monocytes from SN and AL cattle. There was no difference in NO production among groups. Results show that BLV, despite infecting B lymphocytes, alters innate immune functions of monocytes isolated from BLV-infected cows expressing PL.

Avaliação ultrassonográfica de componentes umbilicais inflamados em bezerros da raça Holandesa com até 30 dias de vida

Umbilical disorders deserve mention among the illnesses affecting calves in the first month of life. The high incidence during this phase of life of newborns and relevant economic losses arising from mortality, cost of treatment and veterinary care, beyond sequelae may determine lower weight gain and milk production. The diagnosis of these diseases is often hampered by the difficulty to detect the involvement of intra-abdominal umbilical structures, which negatively affect the choice of the most appropriate treatment and the actual outcome for each calf. In the present study, we performed ultrasound examinations of calves with inflammation/infection in the umbilical components and observed some characteristics related with measurements and echogenicity present in umbilical affected components. From these evaluation it was concluded that the wall thickness of the umbilical vessels is the more reliable standard to determine changes in these components, as compared with that of the diameter of the umbilical vessels. Furthermore, from this study we observed some peculiarities of involution of the intra-abdominal umbilical cord components in healthy Holstein calves used for the control group to characterize the behavior of the umbilical structures during the progress of the age in the newborns. It is noteworthy that the comparison of these results with those found in the rare literature available showed notable differences.

Fagocitose intensificada de Corynebacterium pseudotuberculosis por células da série monócito-macrófago de caprinos naturalmente infectados pelo vírus da artrite encefalite

Caprine arthritis encephalitis (CAE) and caseous lymphadenitis (CL) have high incidence and transmissibility in small ruminants. Since both virus have tropism for macrophages and monocytes and affect the innate immune response, it is believed that CAE can predispose the animal to infection by Corynebacteruim pseudotuberculosis, the etiological agent of CL. To confirm this hypothesis, we evaluated phagocytosis from the monocyte-macrophage cells from 30 Saanen goats. Goats were uniformly divided in two groups according to results of agar gel immunodiffusion test for CAE virus (CAEV). Peripheral blood mononuclear cells were isolated by density gradient centrifugation and the monocyte-macrophage cells were isolated from the mononuclear cells by their adhesion properties in plaques. Afterwards, phagocytosis of C. psudotuberculosis was performed for two hours at 37oC, 5% of CO2, and assessed by microscopic visualization. There was no difference in the percentage of monocyte-macrophage cells that phagocytozed C. bovis between groups (P=0.41). However, when phagocytosis rates were classified according to the number of C. pseudotuberculosis phagocyted, the percentage of monocyte-macrophage cells that internalized more than 12 bacteria were higher in serologically CAEV positive animals compared to the serologically negative ones (P<0.001). Furthermore, a positive and significant correlation (r = 0.488; P = 0.006) between the percentage of monocyte-macrophage cells that internalized more than 12 bacteria and the percentage of monocyte that were carrying out phagocytosis was also encountered in serologically CAEV positive goats, however the same were not observed in serologically negative ones. These results demonstrated an alteration in the intensity of C. pseudotuberculosis phagocytosis by monocytes-macrophages from goats infected by CAEV. Thus, these results indicated that goats infected with CAEV may be more susceptible to CL.

Liberação de peróxido de hidrogênio por fagócitos de glândulas mamárias bovinas hígidas e infectadas

The purpose of the present study was to evaluate the hydrogen peroxide (H2O2) release by phagocytes from infected and uninfected mammary glands in dairy cows. Thus, milk samples from 73 quarters were divided in healthy and infected samples according to bacteriological culture and somatic cell count (SCC). After separation of milk cells, the samples were submitted to differential SCC and hydrogen peroxide release by oxidation of phenol red. There was a lower H2O2 release by phagocytes from infected quarters, as well as, a negative correlation between the H2O2 release by phagocytes and SCC (r=-0.34; P=0.0025) and percentage of neutrophils (r=-0.24; P=0.04). Furthermore, it was observed a tendency toward a lower H2O2 release by phagocytes stimulated by phorbol 12-myristate 13-acetate in the infected quarters. However, a higher H2O2 release by phagocytes was observed in milk samples from infected quarters by the estimation of the H2O2 release by phagocytes in 1mL of milk according to SCC mL-1 of each sample. The present study showed a decrease in H2O2 release by the infected quarters which indicate lower microbicidal activity. However, the higher H2O2 release by phagocytes in 1mL of milk in the infected quarters may contribute to recruitment of leukocytes to the site of infection and the persistence of infection.

Efeito de medicamentos indicados para a prevenção da mastite bovina no período seco sobre a função fagocítica in vitro de leucócitos do leite de caprinos

The use of specific anti-mastitis drugs is indicated in dry cow therapy to prevent infections in the following lactation. Nonetheless, cells active in the dry period are of fundamental importance for the involution of the mammary gland and its recovery for the following lactation. Since there are no specific drugs for dry goat therapy, the dry cow therapy drugs tend to be misused in goats despite of the anatomical and physiological differences apart from the particularities of the two species. The objective of the present study was to evaluate the influence of five drugs specific for dry cow therapy on the function of goat milk phagocytes. Somatic cells were isolated from 20 milk samples of 10 lactating goats that had not been treated for mastitis during the previous 30 days. Milk samples were collected properly and microbiological culture yielded negative results. Cells adherent to glass coverslips were treated with commercially available dry cow therapy drugs containing active principles such as Gentamicin (M1), Cephalonium anhydrous (M2), Ampicillin (M3), Cloxacillin benzathine (M4) and Cephapirin benzathine (M5). Phagocytosis of Zymosan particles was evaluated. Mean phagocytosis indexes of cells treated with M2 (15.12% ± 16.22), M3 (6.02% ± 7.96), M4 (4.54% ± 5.45) and M5 (2.47% ± 4.64) were lower (p<0.001) than mean phagocytosis index of the control group (40.67% ± 19.68). Mean phagocytosis index of cells treated with M2 was greater (p<0.05) than those treated with M3, M4 and M5, whereas means of the latter three treatments were statistically similar. M1-treated cells did not adhere adequately to the cover slips, making it impossible to evaluate phagocytosis in this group. The results obtained enable the conclusion that drugs used affected milk phagocytes negatively. However, interference on somatic cell function is not the sole factor determining an unsuccessful dry period therapy, since the efficacy of the active principle on pathogens responsible for infectious processes also has to be considered.

Using thermography as a diagnostic tool for omphalitis on newborn calves

The objective was to verify if thermography is able to detect inflammatory signs on the skin surface by comparing the umbilical region of healthy calves and calves presenting omphalitis. Twenty healthy calves (control group) had their lateral umbilical region and abdominal region examined with a thermal imaging camera in order to obtain a regional thermograph. The thermographic examination was then performed on 27 calves (Omphalitis group) presenting omphalitis diagnosed by physical examination. The maximum temperature of the lateral umbilical region in calves (aged < 30 days) was 35.7°C ± 1.8 for the control group and 37.0°C ± 1.1 for the omphalitis group and was significantly different (p = 0.002). No difference was found on the temperature of the abdominal umbilical region. In the abdominal and lateral region the highest temperature site was differently positioned between the groups. In conclusion, thermography is able to detect inflammatory signs on the skin of newborn calves and has advantages as a non-invasive, fast and safe method of supporting veterinary diagnosis.