ABSTRACT The study aimed to assess the effect of progressive neutralization on the antimicrobial properties against bacteria and yeasts of wood vinegar obtained from the pyrolysis of Eucalyptus urograndis (clone I144) wood. Wood samples were carbonized at a heating rate of 0.9 °C min-1 until a final temperature of 450 °C, totalizing 8 hours of carbonization. The raw pyrolysis liquids were left to settle, and the aqueous fraction was separated. Then, the aqueous fraction (raw wood vinegar - WV) was purified to yield the WV. WV samples were collected and neutralized from pH 2.5 until 7.5 (2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0, and 7.5, by adding NaOH solution. Through the broth microdilution method, the antimicrobial effect of the neutralized samples at each pH was assessed on Pseudomonas aeruginosa (ATCC 27853), Salmonella enteritidis (ATCC 13076), Staphylococcus aureus (ATCC 25923), Streptococcus agalactiae (CEPA CLINICA), and Candida albicans (ATCC 10231). The minimum inhibitory concentration (MIC) and minimum bactericidal (and fungicidal) concentrations were determined through in vitro technics. Results were subjected to logarithmic regression analysis, and statistical models were fitted for each microorganism in the assessed pH range; as pH increased, a progressive decrease in the CIM increased, demanding higher concentrations of WV to inhibit microbial growth. The more resistant strains were S. aureus and S. agalactiae, which required an increase in WV concentration from a minimum of 6.25% at pH 2.5 to reaching 50% at pH 6.0. When at pH 7.0, both strains were not inhibited even at 50% (the highest concentration evaluated in the study). In contrast, C. albicans proved to be the most sensitive strain, starting from 3.12% EP at pH 2.5 and requiring only 25% for inhibition at pH 7.0. The behavior of P. aeruginosa and S. enteritidis followed the pattern of C. albicans, differing only at pH 7.0, where they required 50% of EP. As observed, even at neutral and slightly alkaline pH, the inhibitory activity of EP on microbial growth was maintained to some extent. Nevertheless, even when neutral and slightly alkaline pH values are reached, the inhibitory activity remains at a certain level. Higher pH values of the WV were associated with lower antimicrobial activity. However, its activity remained even at neutral and slightly alkaline pH values.

RESUMO O presente trabalho teve como objetivo avaliar o efeito da neutralização progressiva na atividade antimicrobiana do extrato pirolenhoso (EP) da madeira do híbrido Eucalyptus urophylla x Eucalyptus grandis (clone I144). Amostras de madeira foram carbonizadas a uma taxa de aquecimento de 0.9 °C min-1 até a temperatura final de 450 °C, perfazendo 8 horas de carbonização. Os líquidos brutos da carbonização foram deixados em repouso e a fração aquosa foi separada. A fração aquosa correspondente ao EP bruto foi destilada obtendo o EP purificado. Alíquotas de EP purificado foram progressivamente neutralizadas do pH 2.5 até 7.5, respectivamente, 2,5, 3,0, 3,5, 4,0, 4,5, 5,0, 5,5, 6,0, 6,5, 7,0, e 7,5, por meio da adição de NaOH. Com o método da micro-diluição em caldo, o efeito antimicrobiano das amostras neutralizadas em cada pH foi avaliado contra Pseudomonas aeruginosa (ATCC 27853), Salmonella enteritidis (ATCC 13076), Staphylococcus aureus (ATCC 25923), Streptococcus agalactiae (CEPA CLINICA) e Candida albicans (ATCC 10231). As concentrações inibitórias mínimas e as concentrações bactericida e fungicida mínimas foram determinadas por técnicas in vitro. Os resultados foram analisados por regressão logarítmica e modelos estatísticos foram ajustados para cada microrganismo em cada pH. Na determinação da CIM, foi detectada uma perda progressiva da atividade antimicrobiana do EP com a neutralização, exigindo, conforme o pH caminhava para 7.0, concentrações mais elevadas de EP para resultar em inibição. As cepas que demonstraram maior resistência foram S. aureus e S. agalactiae. Esses microrganismos partiram da exigência de concentrações de 6.25% de EP, em pH inicial (2.5), e chegaram a requerer 50% em pH 6.0. Quando em pH 7.0, ambas as cepas não foram inibidas nem a 50% (maior concentração avaliada no estudo). Em contrapartida, C. albicans se mostrou a cepa mais sensível, partindo de 3.12% de EP, em pH de 2.5, e exigindo apenas 25% para inibição em pH 7.0. O comportamento de P. aeruginosa e S. enteritidis acompanhou o padrão da C. albicans, diferenciando-se apenas em pH 7.0, onde exigiram 50% de EP. Como observado, mesmo em pH neutro e ligeiramente alcalino, a atividade inibitória do EP ao crescimento microbiano se manteve em certa extensão.

Microorganisms are becoming resistant to the commonly used chemical disinfectants. Thereby, these chemical products should now be replaced by natural ones. In this context, this research aimed to evaluate the disinfectant activity of the extract and decoction of Libidibia ferrea leaves in different surfaces. Thus, two forms of jucá leaf extraction (decoction and hydroalcoholic extraction) were tested through the diffusion disk technique from Kirby and Bauer, growth curve, acceptability test with the population, and surface test. Results showed sensibility to decoction of S. aureus and E. faecalis strains; however, for the extract, the strains that demonstrated sensibility were S. aureus, P. aeruginosa, Micrococcus spp. Corynebacterium spp., and S. Typhimurium in the diffusion disk test. A reduction of the bacterial charge throughout the growth curve was seen through the absorbance values after 24 hours to the strains of E. coli, E. feacalis, Micrococcus spp. and K. pneumoniae in the concentration of 100 mg/mL of the decoction and extract. Regarding the surfaces test, there was a reduction in the bacterial charge in all tested strains. Therefore, the L. ferrea may be used as an effective alternative disinfectant measure.

Abstract Studies on semen and sperm cells are critical to develop assisted reproductive technologies for the conservation of the collared peccary. The objective of the study was to compare the effect of different antibiotics on the bacterial load and sperm quality during short-term storage of peccary semen. Fresh semen samples from 10 males were extended in Tris-egg yolk or Tris-Aloe vera supplemented with streptomycin-penicillin (SP; 1 mg/mL - 1000 IU/mL or 2 mg/mL - 2000 IU/mL) or gentamicin (30 µg/mL or 70 µg/mL) before storage at 5°C. Bacterial load and sperm motility, membrane integrity and function, mitochondrial activity, and morphology, were evaluated at different time points for 36 h. The SP and gentamicin treatments concentration inhibited (p < 0.05) bacterial growth for 36 h regardless of the extender. Compared to the other treatments, Tris-egg yolk plus 70 µg/mL gentamicin maintained the sperm parameters for longer, including total motility (41.9 ± 6.1%) at 24 h, and membrane integrity (58.3 ± 2.1%) at 36 h. In contrast, the highest SP concentration in both extenders impaired sperm membrane integrity at 36 h (p < 0.05). For the liquid storage of collared peccary semen, it therefore is recommended to use Tris extender supplemented with egg yolk and gentamicin (70 µg/mL).

Abstract The use of antibacterial substances as additives in extenders for ensuring the sanitary quality of the semen employed in reproductive biotechniques and preserving it from bacterial deterioration has been reported since the mid-twentieth century. However, the deleterious effects of these drugs on the sperm quality as well as their effectiveness in controlling bacterial growth in the preserved semen have been questioned. The aim of this review was to report the antimicrobials primarily used in the extenders added to the semen of mammals, and to present alternatives to their use. Among the various mammalian species, there is a large variation regarding the antimicrobial types added to semen extenders as cephalosporins (ceftiofur, cefdinir, eg) and quinolones (ofloxacin, ciprofloxacin), alone or in combination with large action spectra substances as penicillin-streptomycin and gentamicin-tylosin-lincomycin-spectinomycin. To combat problems related to bacterial resistance to these drugs, the emergence of alternatives is increasingly evident. Among these alternatives, use of physical methods as centrifugation and filtration, as well as the use of antimicrobial peptides and other substances from different origins have been highlighted for presenting antimicrobial potential.