The aim of this study was to investigate the possibility of using essential oils of Thymus vulgaris as an alternative preservative for chromed leather. The differences between the chemical composition of commercial and pure essential oils of thyme were determined. It was observed that these differences have an influence on the antibacterial activity of essential oils. Gram-positive bacteria were found to be more sensitive to the essential oils of thyme than Gram-negative bacteria. The bacteria Pseudomonas aeruginosa had a low sensitivity to the action of the selected essential oils of thyme, but the leather samples treated with the essential oils of thyme remained resistant to the action of these bacteria. As the main result of this study, it was concluded that the essential oil of thyme could be used as a preservation agent in the leather tanning industry. The leather preserved with 2-(thiocyanomethylthio)benzothiazole had weaker protection after four weeks compared to the samples treated with the essential oil of thyme when the amount of the used essential oil was not less than 3% of the wet-blue mass. The essential oil of thyme was the more active component in the mixture of essential oil and synthetic biocide used for the preservation of leather.

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The p-aminobenzoic acid was applied for the synthesis of substituted 1-phenyl-5-oxopyrrolidine derivatives containing benzimidazole, azole, oxadiazole, triazole, dihydrazone, and dithiosemicarbazide moieties in the structure. All the obtained compounds were evaluated for their in vitro antimicrobial activity against Staphylococcus aureus, Bacillus cereus, Listeria monocytogenes, Salmonella enteritidis, Escherichia coli, and Pseudomonas aeruginosa by using MIC and MBC assays. This study showed a good bactericidal activity of γ-amino acid and benzimidazoles derivatives. The antimicrobial activity of the most promising compounds was higher than ampicillin. Furthermore, two benzimidazoles demonstrated good antimicrobial activity against L. monocytogenes (MIC 15.62 µg/mL) that was four times more potent than ampicillin (MIC 65 µg/mL). Further studies are needed to better understand the mechanism of the antimicrobial activity as well as to generate antimicrobial compounds based on the 1-phenyl-5-oxopyrrolidine scaffold.

Bovine respiratory disease caused by Mycoplasma bovis is a major health problem of cattle worldwide. It inflicts considerable financial losses on beef herds and is the most common cause of mortality in dairy cattle. Bacteriological examination of 35 nasal cavity samples from calves younger than three months of age identified Mycoplasma bovis in eight (22.9%) samples. These cattle were followed until 17 months of age, and repeated examination of nasal cavity samples before necropsy identified Mycoplasma bovis in four (11.4%) samples. At necropsy and lung samples for bacteriological and histological examination were collected. To identify microorganisms from the Mollicutes class isolated from the nasal cavities of cattle we used the PCR method. Furthermore, Mycoplasma bovis was identified on the grounds of biochemical characteristics and by the disk growth inhibition test. The organism was found in 5.7% of calves younger than three months of age in combination with Pasteurella spp. Mycoplasma bovis in combination with Pasteurella multocida and Mannheimia haemolytica was isolated from 5.7% and 2.9% of cattle at 17 months. However, Pasteurella multocida was common in cattle at 17 months and Mannheimia haemolytica was isolated from both age groups of cattle. Histopathological examination of lung samples revealed broncho-interstitial pneumonia in 14.3% of samples. Mycoplasma bovis was isolated from 60.0% of broncho-insterstitial pneumonia cases. The organism was isolated more frequently from the group of calves rather than from the cattle group (P < 0.05). The most common bacterial agents were Pasteurella multocida and Mannheimia haemolytica.

New N,N-disubstituted β-amino acids and their derivatives with thiazole, aromatic, and heterocyclic substituents were synthesized from N-phenyl-N-thiocarbamoyl-β-alanine by the Hantzsch method; derivatives with hydrazone fragments were also obtained. Some of the synthesized compounds exhibited discrete antimicrobial activity, and 3-[(4-oxo-4,5-dihydro-1,3-thiazol-2-yl)(phenyl)amino]propanoic acid was found to promote rapeseed growth and to increase seed yield and oil content.

ABSTRACT:The purpose of this study was to determine the antibacterial susceptibility of field isolates of Mycoplasma bovis originating from the upper respiratory tract of cattle of different ages. Bacteriological examination of 90 nasal swabs collected from calves at three months of age identified M. bovis in 31 (34.44%) samples. Seventeen (18.88%) of these animals still housed M. bovis in their nasal cavity at nine months and five animals (5.55%) still at seventeen months of age. M. bovis were confirmed by biochemical and antigenic methods. To confirm that these belonged to the M. bovis species isolated mycoplasmas were tested using the PCR method. Fifteen field strains of M. bovis isolated from the same cattle at three, nine and seventeen months (five strains from each age group) were selected for antibacterial susceptibility testing against six groups of antimicrobial agents using an agar dilution method. The MIC 90 ranges established for tylosin, tulathromycin, enrofloxacin, florfenicol and lincomycin were 0.39-0.78 µg/ml, 0.50-1.00 µg/ml, 0.78-1.56 µg/ml, 3.12 µg/ml and 0.39-0.78 µg/ml, respectively. The range of MIC 90 for oxytetracycline was from 50 to 100 µg/ml. Preliminary examination of the antimicrobial susceptibility of field strains of M. bovis did not reveal significant differences between different age groups of cattle. After evaluation of the MIC 90 data with the SPSS 13.0 statistical package it was found that M. bovis isolates from animals at three, nine and seventeen months were similarly susceptible to tylosin and tulathromycin. Statistically significant differences in susceptibility of M. bovis isolated from cattle of different ages were found to florfenicol compared with tulathromycin (P < 0.01), lincomycin (P < 0.01) and enrofloxacin (P < 0.05). The susceptibility of all M. bovis isolates to oxytetracycline and penicillin G significantly differed from the sensitivity to all other antimicrobial agents used in the present study (P < 0.05). The in vitro susceptibility test showed that field isolates of M. bovis isolated from cattle of different ages were similarly sensitive to tylosin, tulathromycin, lincomycin and enrofloxacin. It was also determined that the field strains are resistant to oxytetracycline.

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The aim of this study was to detect Mycoplasma species in the respiratory tract of 110, 310 and 510 day-old groups of cattle by serological, bacteriological and histopathological investigations. Antibodies against M. bovis were found in 75% of the 110 day-old, in 50% -of the 310 day-old and in 55% -of the 510 day-old groups of cattle.Bacteriological examination of the samples from nasal cavities revealed that Mycoplasma carriers were found in 60% of the 110 day-old group of cattle, 40% of the 310 day-old and 40% of the 510 day-old group of cattle. Using the PCR method Mycoplasma was isolated from 25% of lung samples of the 510 day-old group of cattle. Mycoplasma bovis and Mycoplasma dispar were confirmed by serological investigations. Foci of bronchointerstitial pneumonia were determined by histopathological examination in 27.5% of lung samples. Mycoplasma bovis was isolated in 72.7% of bronchointerstitial pneumonia cases. Data processing with an SPSS 13.0 statistical package led to the conclusion that Mycoplasma bovis was found more frequently in the 110 day-old group of cattle (the youngest age group in this study) rather than in the 310 and 510 day-old groups of cattle (χ 2 = 6.531; p = 0.038). The results obtained led to the conclusion that serological, bacteriological and histopathological examinations are important in detecting particular animal -carriers of Mycoplasma.