Extract of Mangifera indica L. leaves may reduce biofilms of Staphylococcus spp. in stainless steel and teatcup rubbers.

Human ingestion of antimicrobial residues in dairy products is a problem of public health. In this study we evaluated antibacterial effectiveness of aqueous and ethanolic leaf extracts of Mangifera indica L. as a natural alternative for reduction of Staphylococcus spp. biofilms. Eight Staphylococcus spp. strains from cows with mastitis and the Staphylococcus aureus strain (ATCC 25923) were evaluated. High performance liquid chromatography indicated the presence of phenolic compounds in the aqueous extract. Agilent Technologies gas chromatography revealed the presence of phenolic compounds, carbohydrates, and gallic acid in ethanolic extract. The tannin contents were 2.27 ± 0.01 and 2.67 ± 0.01% for ethanolic extract and aqueous extract, respectively. Extracts were evaluated in agar diffusion test and the size of inhibition zones were compared. The ethanolic extract was the most effective, showing minimum inhibitory concentrations and minimum bactericidal concentrations between 1.8-7.5 and 15.1-45.3 mg/ml, respectively. After tannin removal, the extracts were less effective, indicating these secondary metabolites as one of the main antibacterial compounds. The ethanolic extract at 45.3 mg/ml reduced mature biofilms in teat rubber (average: 3.91 log reduction) and stainless steel (average: 3.87 log reduction) after 5 min of contact. The extracts of M. indica leaves represent natural alternatives against Staphylococcus spp. strains and the ethanolic extract shows potential as a natural sanitizer.

Plants of the Cerrado with antimicrobial effects against Staphylococcus spp. and Escherichia coli from cattle.

BACKGROUND: Both diarrhea in calves and mastitis in cows limit cattle production. The bacteria involved in these diseases have shown multi-resistance to antimicrobials, however plant metabolites therefore can provide an alternative method of control. This study selected and characterized Cerrado plant extracts showing inhibitory effects against Escherichia coli and Staphylococcus spp. from cattle. Thirteen leaf extracts were initially screened and diameters of inhibition zones produced against the pathogens were recorded using an agar disk diffusion method. Total condensed tannin contents were determined and antibacterial activities were analyzed after tannin removal from the five selected extracts. The minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were evaluated by macro-dilution antimicrobial susceptibility tests, and the extracts were characterized by high performance liquid chromatography. RESULTS: Inter- and intra-specific bacterial variations in the susceptibility to the extracts were detected. The aqueous extract (AE) from Caryocar brasiliense Cambess. leaves produced larger inhibition zones against E. coli strains than did other selected extracts. However, the AE from Schinopsis brasiliensis was the most effective against Staphylococcus spp. strains (P < 0.001). The MIC of ethanolic extracts (EE) from C. brasiliense (0.27 mg/mL) and S. brasiliensis (0.17 mg/mL) were lower than those of other extracts. The MIC and MBC of the Annona crassiflora EE were 6.24 mg/mL for all bacteria. Flavonoids were the main metabolites detected in the A. crassiflora EE as well as in the AE and EE from C. brasiliense, while tannins were the main metabolites in the S. brasiliensis leaf extracts. CONCLUSION: The AE from C. brasiliense was more effective against Gram-negative bacteria, while the AE from S. brasiliensis was more effective against Gram-positive bacteria. A. crassiflora EE and S. brasiliensis extracts are potent bactericide. After removal of the tannins, no antimicrobial effects were observed, indicating that these metabolites are the main active antibacterial components.

Bastonetes Gram-negativos aeróbios e anaeróbios facultativos no fluido ruminal de bovinos de corte alimentados em pastagem lignificada e em novilhos com acidose ruminal / Aerobes and anaerobe facultative Gram-negative rod-shaped bacteria in the ruminal fluid of beef cattle fed lignified pasture and steers with ruminal acidosis

Objetivou-se analisar a população de bastonetes Gram negativos aeróbios e anaeróbios facultativas no suco ruminal bovinos zebuínos de diferentes categorias, alimentados em pastagem tropical, e de novilhos alimentados com alto teor de grão e sem volumosos. Foram coletados fluido ruminal de 32 vacas, 50 novilhos e 50 bezerros alimentadas em pastagem de Brachiaria spp. e de 20 novilhos com acidose ruminal. Após diluições decimais, amostras foram inoculadas em placas contendo ágar MacConkey a 39°C. Para a identificação dos gêneros mais frequentes foram utilizadas provas bioquímicas. A concentração dessas bactérias não diferiu no ambiente ruminal de vacas, novilhos e bezerros de corte alimentados com pastagem tropical lignificada. Os gêneros mais frequentemente identificados para esses animais foram Escherichia, Enterobacter e Klebsiella. Novilhos alimentados sem volumoso e com acidose apresentaram maior taxa de detecção e maior população dessas bactérias no ambiente ruminal (>6 log/ml) quando comparados aos novilhos alimentados somente em pastagem. A espécie Escherichia coli foi predominante entre as bactérias isoladas do fluido ruminal de novilhos alimentados com dieta com alta concentração de grãos e com acidose (p<0,01). Constatou-se que em bovinos de corte, criados em pastagem tropical lignificada, a população desses microrganismos é baixa no ambiente ruminal e com maior diversidade de gêneros bacterianos. Entretanto em novilhos confinados e alimentos sem volumoso, apresentando acidose ruminal subaguda, ocorre desequilíbrio populacional com aumento da população de E. coli...

This study aimed to analyze the population of Gram negative bacteria, rod-shaped aerobic and facultative anaerobes, in ruminal fluid of health Zebu cattle of different categories fed in tropical pasture and steers fed high levels of grain and without bulky. Rumen fluid from 32 cows, 50 steers and 50 calves fed on Brachiaria spp. and 20 steers with ruminal acidosis were collected. After decimal dilutions, the samples were inoculated on petri dishes with agar MacConkey at 39°C. Biochemical tests were used to identify the most common genera these bacteria. The concentration of these bacteria did not differ in the rumen of cows, calves and calves fed lignified tropical pasture and the most frequently identified genera for these animals were Escherichia, Enterobacter and Klebsiella. However, steers fed without forage and with acidosis showed a higher detection rate and larger population of these bacteria in the rumen (>6 log/ml) compared to steers fed only pasture. The Escherichia coli species was predominant among theses bacteria isolated from the rumen fluid of steers with acidosis (p<0.01). In beef zebu cattle raised on pasture lignified, the population of these microorganisms in the rumen is low showing greater diversity of genera. However in confined zebu steers fed without forage and with sub acute ruminal acidosis occur disequilibrium with increased E. coli population...