Mammary leukocyte response to drug therapy

Outcomes after treatment of nonsevere gram-negative clinical mastitis with ceftiofur hydrochloride for 2 or 5 days compared with negative control

A study was conducted at 3 commercial dairies in California to compare outcomes of treating nonsevere (mild and moderate) gram-negative (GN) clinical mastitis (CM) with intramammary (IMM) ceftiofur HCl (125 mg of ceftiofur HCl per tube) in either 2-d (SP2) or 5-d (SP5) treatment programs compared with nontreatment (CON). In addition, we contrasted results from cases classified as mild and moderate. Four hundred fifteen cases were included in the final dataset, including 135 CON, 133 SP2, and 147 SP5. Milk from quarters with CM was sampled for on-farm culture (OFC) to differentiate gram-positive (GP) and GN bacteria, with results known within 24 h. Those with GN infections were randomly assigned to experimental groups, while those with GP, mixed infections, and contaminated samples did not continue in the study and received standard farm therapy. For cows with GN infections, a sample was submitted for MALDI-TOF assay. Only nonsevere cases were enrolled, and all quarters yielded monocultures of GN species. Clinical scores were obtained 0, 1, 2, 3, 4, 5, 14, 21, and 28 ± 3 d relative to enrollment. Milk samples were collected from quarters 14, 21, and 28 ± 3 d after enrollment, and submitted for routine culture and, when appropriate, submitted to MALDI-TOF evaluation. For many response criteria, there were significant interactions between treatments and CM severity scores at the time of enrollment, with effectiveness of ceftiofur HCl treatment being more beneficial compared with CON as mastitis clinical severity increased. While most treatment responses were significant for animals with mild or moderate GN mastitis, the largest responses were noted among cows with moderate CM cases.

Control of subclinical bovine mastitis

A clinical trial was conducted on a dairy farm. 26 animals were divided into 2 groups of 13 each, pairing on clinical and subclinical mastitis status, milk production and number of lactations, assigning both animals and treatments by a systematic random method. One group received homoeopathic treatment, the other placebo. Monthly milk production was carefully recorded for each animal, as were the results of the California Mastitis Test (CMT) performed on each quarter of the udder. The proportion of affected quarters according to CMT was 32% in the treated group, and 68% in the control group. The odds ratio of the difference shows that animals receiving placebo presented 4.5 (1.78–11.73) times more subclinical mastitis than those under homoeopathic treatment (p<0.05). Average milk production in the treated group did not differ significantly from that of the control group (p>0.05). The study confirms previous observations of the benefit the homoeopathic method can provide in disease control in animal populations.

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

O uso de medicamentos antimamíticos específicos para vacas no período seco é indicado para prevenção de infecções na lactação seguinte. Não obstante, a ação das células envolvidas no período de secagem tem fundamental importância para a involução da glândula mamária e seu restabelecimento para a lactação subseqüente. A indisponibilidade de tais medicamentos para uso em cabras tem resultado na extrapolação do uso de produtos recomendados para vacas sem que se considerem as particularidades e diferenças anátomo-fisiológicas entre as espécies bovina e caprina. O presente estudo teve por objetivo avaliar a influência de cinco antimamíticos específicos para vacas secas sobre a função dos fagócitos provenientes de leite caprino. Para tal, fez-se o isolamento de células somáticas de 20 amostras de leite provenientes de 10 cabras lactantes, sem antecedentes de tratamento de mamite nos últimos 30 dias, sob condições higiênico-sanitárias de colheita e com resultados negativos ao cultivo microbiológico do leite. As células aderidas a lamínulas de vidro foram confrontadas com formulações contendo princípios ativos disponíveis no mercado como Gentamicina (M1), Cefalônio Anidro (M2), Ampicilina (M3), Cloxacilina Benzatínica (M4) e Cefapirina Benzatínica (M5). Avaliou-se, por microscopia, a fagocitose de partículas de Zymosan. As médias dos índices de fagocitose das células submetidas ao tratamento com M2 (15,12% ± 16,22), M3 (6,02% ± 7,96), M4 (4,54% ± 5,45) e M5 (2,47% ± 4,64) foram menores (p<0,001) que a média dos índices de fagocitose do grupo controle (40,67% ± 19,68). A média dos índices de fagocitose das células submetidas ao tratamento com M2 foi maior (p<0,05) que as médias dos tratamentos com M3, M4 e M5 enquanto estas foram estatisticamente iguais entre si. As amostras celulares submetidas ao medicamento M1 exibiram adesão insuficiente ou ausente às lamínulas, inviabilizando a avaliação da fagocitose por meio da técnica utilizada. Os resultados obtidos permitem concluir que os medicamentos estudados exerceram influência negativa sobre os fagócitos do leite, porém, esta interferência sobre as funções das células somáticas não pode por si só determinar o insucesso da terapia proposta para o período seco, pois deve ser considerada, outrossim, a eficácia do princípio ativo sobre o patógeno causador do processo infeccioso.

Impact of ibuprofen therapy in the outcome of experimental pneumococcal acute otitis media treated with amoxicillin or erythromycin

The impact of ibuprofen combined with amoxicillin or erythromycin for therapy of penicillin-resistant pneumococcal acute otitis media (AOM) was evaluated in a gerbil model. Ibuprofen (at 2.5 or 7.5 mg/kg, orally) and/or amoxicillin or erythromycin (5 mg/kg each, s.c.) were administered at 5 h (early therapy, as single-dose regimen) or at 18 h (delayed therapy, five doses) postinoculation (PI). Each antibiotic alone and combined with ibuprofen was more effective administered as early regimen than as delayed treatment when evaluating the presence of otorrhea, otoscopic aspect, culture-positive and bacterial counts in middle ear (ME) samples, and loss of body weight. There was a trend for a better bacteriological outcome in animals receiving amoxicillin or erythromycin and ibuprofen, especially with the high dose. Such a dose of ibuprofen, associated with each antibiotic regimen, also preserved the animal well-being, avoiding a great weight loss in comparison to those receiving the antibiotic alone but a statistically significant difference was only observed for animals receiving delayed therapy with erythromycin and high-dose ibuprofen. In conclusion, ibuprofen combined with antibiotics seemed to improve the outcome of this experimental pneumococcal AOM.

Pharmacodynamics of isoflupredone acetate in an endotoxin-induced mastitis model

The effect of intravenous administration of the steroidal drug isoflupredone acetate on lactating dairy cows with mastitis induced using gram-negative bacterial endotoxin was investigated. Cows were randomly assigned to one of four treatment groups: untreated controls, isoflupredone acetate only, mastitis only, and mastitis plus isoflupredone acetate. Isoflupredone acetate was given to treated groups at a dose of 20 mg intravenously, once. Mastitic cows receiving treatment were given isoflupredone acetate after the development of clinical signs. When compared with untreated mastitic controls, cows with endotoxin-induced mastitis treated with isoflupredone acetate did not exhibit measurable differences in heart rate, rectal temperature, rumen motility, or changes in mammary gland surface area in the 14 h following the administration of intramammary endotoxin. Healthy cows treated with isoflupredone acetate had a higher heart rate over the 14 h after drug administration than did untreated healthy controls. When compared with untreated mastitic controls, cows treated with isoflupredone acetate did not exhibit statistically significant differences in milk production following endotoxin-induced mastitis.

Neutrophil apoptosis during the resolution of bovine mammary gland injury

The role of neutrophil apoptosis in the resolution of bovine mammary gland injury induced by intramammary administration of physiological buffered saline (PBS) or lipopolysaccharide (LPS) was investigated. Twenty mammary glands of five non-pregnant heifers were used in the two studies and each animal received both stimuli. Samples of cell populations were collected by mammary gland lavages before and 24, 48, 72 and 96 hours after treatment and examined by light microscopy and staining for myeloperoxidase (MPO). A marked influx of neutrophils into the mammary gland was observed 24 hours after stimulation. At the same time, apoptotic neutrophils and MPO-positive macrophages (MAC) were identified in the samples. The numbers increased to reach maximum values at 48 hours after stimulation with PBS and at 72 hours after stimulation with LPS. The observed differences in the length of the resolution period indicate that neutrophil viability can be modulated by delaying the apoptotic process. Apoptosis of neutrophils and their subsequent phagocytosis by MAC can be regarded as a significant mechanism in the removal of neutrophils from the acutely injured mammary glands and, hence, in the resolution of bovine mastitis.

Effect of cephapirin and mecillinam on the phagocytic and respiratory burst activity of neutrophil leukocytes isolated from bovine blood

Antimicrobial therapy is the most commonly used treatment of bacterial infections in dairy cows. Polymorphonuclear neutrophil leukocytes (PMN) play an important role in the first line defence against invading bacteria and it is important that the function of PMN is not compromised by antibiotics. We investigated the in vitro effect of cephapirin, a first generation cephalosporin, and mecillinam, an amidinopenicillin with activity against mainly Gram-negative bacteria, on phagocytosis and respiratory burst activity of PMN isolated from bovine blood. After in vitro incubation of PMN with different concentrations of the antibiotics, phagocytosis was evaluated by flow cytometry and respiratory burst activity was evaluated by registration of chemiluminescence (CL) with a luminometer. None of the investigated concentrations of cephapirin and mecillinam had an effect in vitro on phagocytosis of Escherichia coli by PMN. At high concentrations (100 and 1000 microg/mL), cephapirin and mecillinam reduced the respiratory burst activity of PMN. Part of these suppressive effects could be ascribed to oxidant scavenging. Inhibitory effects of cephapirin were stronger than mecillinam. In conclusion, cephapirin and mecillinam did not seem to affect antibacterial activity of PMN isolated from bovine blood in vitro at therapeutic concentrations.

Measures taken by veterinarians in Sweden in cases of bovine mastitis

A questionnaire concerning the diagnosis and treatment of bovine mastitis was sent to all 350 Swedish food animal practitioners. 287 (82%) of the questionnaires were returned. One of the main aims was to establish if Swedish food animal practitioners used a common therapeutic regime that could be used as a control treatment in future clinical trials. It was found that many factors of importance for the clinical diagnosis of mastitis such as body temperature, duration of the symptoms etc. often were not considered. On the other hand 60-70% of the practitioners regularly took milk samples to obtain a bacteriological diagnosis. Approximately 40% of the veterinarians cultured the milk samples in their home laboratory. Basic measures like frequent emptying of the udder were recommended by only 40-50% of the veterinarians. All responding field veterinarians used the systemic route for administering antibiotics when treating cases of acute, clinical bovine mastitis. The drug of choice, initially, in these cases was benzylpenicillinprocain, which was used by 65-75% of the veterinarians. Twenty-five percent used a broad-spectrum antibiotic, most commonly a combination of penicillin and streptomycin. A minority (5%) directed their initial therapy towards gram-negative bacteria. About 30-40% supported the systemic therapy with intra-mammaries. Other drugs such as NSAID, corticosteroids and oxytocin was used, on a regular basis, by only about 10% of the practitioners.

Influence of medicinal herbs on phagocytosis by bovine neutrophils

Twenty-six herbal preparations made from 24 medicinal herbs, categorized as antipyretics in Chinese materia medica, were tested in vitro to determine their effects upon phagocytosis of 32P-labelled Staphylococcus aureus by neutrophils isolated from bovine blood and milk. The percentage of phagocytosis was determined after incubating (1 hour at 37 degrees C) 1.25 x 10(7) neutrophils, 1 x 10(8) 32P-labelled S. aureus and 10% skimmed milk with herbal solutions. Concentrations of herbal preparations tested were 100%, 10% and 1% (v/v). When compared with PBSS (0.01 M phosphate buffered saline solution) controls, most of the herbs at high concentrations inhibited phagocytosis while at lower concentrations phagocytosis was increased. All 26 herbal preparations significantly increased blood neutrophil activity at their proper concentrations. The most active herbs in promoting blood neutrophil phagocytosis were observed for Herba verbenae, Flos chrysanthemi, Flos lonicerae, Radix sophorae flavescentis, Herba houttuyniae, Radix isatidis, Herba patriniae, Berberini sulfatis at the lowest concentration and for Folium hibisci at the high concentration with the increased percentage of more than 40.0% in comparison with PBSS control. Of the 19 herbal preparations tested with milk neutrophils, 18 herbs greatly increased phagocytosis at suitable concentrations. The most active preparations in stimulating milk neutrophil functions included Folium hibisci, Flos chrysanthemi, Radix bupleuri, Radix stellariae, Herba houttuyniae, Herba senecionis scandentis, Caulis lonicerae and Flos lonicerae which increased phagocytosis by over 35.0%.

Collagen binding, elastase production, and slime production associated with coagulase-negative staphylococci isolated from bovine intramammary infections

Collagen binding, elastase production, slime production, and associated somatic cell counts were determined with 160 strains of coagulase-negative staphylococci isolated from bovine intramammary infections. Mean binding values for type I and II collagen with Staphylococcus epidermidis, S. chromogenes, and S. hyicus strains were 5.8, 6.6, and 7.4 and 4.3, 4.2, and 4.9%, respectively. Eleven of 28 (39.3%) S. epidermidis, 1 of 38 (2.6%) S. chromogenes, and 1 of 94 (1.1%) S. hyicus strains were elastase positive. Slime production was noted with 12 (42.9%) S. epidermidis, 1 (2.6%) S. chromogenes, and 11 (11.7%) S. hyicus strains. No differences in somatic cell counts were observed with type I or type II collagen binding, elastase production, or slime production with S. epidermidis or S. chromogenes. However, somatic cell counts associated with S. hyicus strains with collagen type I binding affinities of greater than 5 and type II binding affinities of greater than 3 were 320.7 x 10(3) compared with 163.9 x 10(3) for strains with lower binding affinities.

Synergistic hemolysis associated with coagulase-negative staphylococci isolated from bovine mammary glands

A total of 353 coagulase-negative staphylococcus (CNS) isolates from infected bovine mammary glands were tested for cytolysin production by using the synergistic hemolysin assay (SHA). Overall, 34.6% of CNS isolates were SHA positive. Human-associated, coagulase-negative staphylococcal species contained the greatest number of SHA-positive strains. Milk leukocyte levels expressed as somatic cell counts (SCC) were elevated with SHA-positive Staphylococcus epidermidis, Staphylococcus hominis, and Staphylococcus warneri strains. Elevated SCC levels were associated with strains of Staphylococcus hyicus and Staphylococcus chromogenes. However, no difference in SCC levels was observed between SHA-positive and SHA-negative strains. Results indicated that the SHA was a sensitive test for the detection of cytolysin-producing CNS.

Effect of some vehicles used in intramammary mastitis preparations on inflammation indicators in milk

The irritant effect of some vehicles used in intramammary mastitis preparations was assessed by indirect mastitis indicators in milk. Mineral oil, soybean oil, peanut oil, a combination of aluminium monostearate, stearic acid and mineral oil as well as isotonic saline were infused intracisternally in cows during mid-lactation. These vehicles induced a selective increase in the number of somatic cells without any notable effects on the permeability marker antitrypsin or the lysosomal enzyme N-acetyl-beta-D-glucosaminidase (NAGase).