Search results

Filters

  • Journals
  • Authors
  • Keywords
  • Date
  • Type

Search results

Number of results: 6
items per page: 25 50 75
Sort by:

Abstract

Effects of fermented extruded rye flour supplements with Lactobacillus sakei KTU05-6 or Pediococcus pentosaceus BaltBio02 on milk production and composition, as well as ruminal parameters, were determined in Lithuanian Black & White dairy cows. Also, determination of antimicrobial activities of tested lactic acid bacteria (LAB) against a variety of pathogenic and opportunistic bacterial strains previously isolated from diseased cattle was performed. The highest antimicrobial activity was demonstrated in L. sakei against S. aureus, and in P. pentosaceus against P. aeruginosa and S. aureus. The count of LAB in the supplements after 72 h of fermentation of extruded rye flour with L. sakei and P. pentosaceus was 9.6±0.4 log10 CFU/g and 9.5±0.3 log10 CFU/g, respectively. All cows (n=60) were fed the same basal diet. The treatment differences were achieved by individually incorporating (65 d.) one of the supplements: L. sakei KTU05-6 (group B; n=20) or P. pentosaceus BaltBio02 (group C; n=20). The control group A (n=20) was on the basal diet only. A supplement fermented with L. sakei does not have a significant influence on dairy cattle milk production and rumen fluid parameters. The type of LAB used has a significant influence (p<0.0001) on microbiological parameters of the rumen (TCM, TCL, TCE). The milk yield was increased (p≤0.05) using P. pentosaceus BaltBio02 supplement, and further research is needed to identify w hat is the main mechanism of the positive action.
Go to article

Abstract

The study was aimed at evaluating microbial contamination on the premises of the sewage treatment plant by determining the concentrations of selected groups of airborne microorganisms. Another objective was to determine the antibiotic sensitivity patterns of isolated strains of staphylococci. The research was conducted in a seasonal cycle, by the impaction method using Merck MAS-100 air sampler. Samples were collected at six sites, each representing a different stage of sewage treatment. The susceptibility of isolated staphylococci was assessed with the disc-diffusion method, following the recommendations of the EUCAST. The results indicate that the microbial population in the air of the investigated area was dominated by mold fungi, whose highest average concentration was recorded at site IV located near the final clarifier (7672 CFU•m-3). Heterotrophic bacteria and mannitol-positive staphylococci were the most numerous at locations where sewage undergoes primary treatment. In each subseuqent stage the number of microorganisms emitted into the air from the sewage was lower. Antibiograms show that more than 50% of Staphylococcus spp. exhibited resistance to penicillin and 20% to rifampicin. In addition, 90% of the analyzed strains were sensitive to other antibiotics. The fungal community included the following genera: Cladosporium, Fusarium, Alternaria, Penicillium, Aspergillus, Aureobasidium, and Acremonium.The highest air contamination with all studied groups of microorganisms was recorded at the locations where mechanical sewage treatment was performed. During the subsequent stages lower numbers of heterotrophic bacteria were emitted into the air. The air in the investigated sewage treatment plant did not contain multidrug-resistant staphylococci.
Go to article

Abstract

This report describes the isolation and characterization of bacterial isolates that produce anti−microbial compounds from one of the South Shetland Islands, King George Is − land, Antarctica. Of a total 2465 bacterial isolates recovered from the soil samples, six (BG5, MTC3, WEK1, WEA1, MA2 and CG21) demonstrated inhibitory effects on the growth of one or more Gram−negative or Gram−positive indicator foodborne pathogens ( i.e. Escherichia coli 0157:H7, Salmonella spp., Klebsiella pneumoniae , Enterobacter cloacae , Vibrio parahaemolyticus and Bacillus cereus ). Upon examination of their 16S rRNA sequences and biochemical profiles, the six Antarctic bacterial isolates were identified as Gram−negative Pedobacter cryoconitis (BG5), Pseudomonas migulae (WEK1), P. corrugata (WEA1) and Pseudomonas spp. (MTC3, MA2, and CG21). While inhibitors produced by strains BG5, MTC3 and CG21 were sensitive to protease treatment, those produced by strains WEK1, WEA1, and MA2 were insensitive to catalase, lipase, a −amylase, and protease enzymes. In addtion, the six Antarctic bacterial isolates appeared to be resistant to multiple antibiotics.
Go to article

Abstract

MDAP-2 is a new antibacterial peptide with a unique structure that was isolated from house- flies. However, its biological characteristics and antibacterial mechanisms against bacteria are still poorly understood. To study the biological characteristics, antibacterial activity, hemolytic activi- ty, cytotoxicity to mammalian cells, and the secondary structure of MDAP-2 were detected; the results showed that MDAP-2 displayed high antibacterial activity against all of the tested Gram-negative bacteria. MDAP-2 had lower hemolytic activity to rabbit red blood cells; only 3.4% hemolytic activity was observed at a concentration of 800μg/ml. MDAP-2 also had lower cytotoxicity to mammalian cells; IC50 values for HEK-293 cells, VERO cells, and IPEC-J2 cells were greater than 1000 μg/ml. The circular dichroism (CD) spectra showed that the peptide most- ly has α-helical properties and some β-fold structure in water and in membrane-like conditions. MDAP-2 is therefore a promising antibacterial agent against Gram-negative bacteria. To deter- mine the antibacterial mechanism(s) of action, fluorescent probes, flow cytometry, and transmis- sion electron microscopy (TEM) were used to study the effects of MDAP-2 on membrane perme- ability, polarization ability, and integrity of Gram-negative bacteria. The results indicated that the peptide caused membrane depolarization, increased membrane permeability, and destroyed membrane integrity. In conclusion, MDAP-2 is a broad-spectrum, lower hemolytic activity, and lower cytotoxicity antibacterial peptide, which is mainly effective on Gram-negative bacteria. It exerts its antimicrobial effects by causing bacterial cytoplasm membrane depolarization, increas- ing cell membrane permeability and disturbing the membrane integrity of Gram-negative bacte- ria. MDAP-2 may offer a new strategy to for defense against Gram-negative bacteria.
Go to article

Abstract

This study is aimed to investigate culturable airborne bacteria concentrations and the composition of methicillin-resistant staphylococci in eleven different locations on the basis of specific activities conducted within different parts of the European side of Istanbul. The highest bacterial levels were observed at the Bakirkoy station (1 100 CFU/m3) while the second highest levels were found at the Bahcelievler station (1 040 CFU/m3) in October; the lowest levels (10 CFU/m3) were measured at other different stations (Atakoy, Yesilkoy). Fifteen methicillin-resistant isolates [Staphylococcus hominis (n=11), S. cohnii spp. cohnii (n=2), S. sciuri (n=1), S. capitis spp. capitis (n=1)] were identified. The disc diffusion method was used to identify the antimicrobial resistance of these isolates, it was observed that the most common resistance was to penicillin (P) (n=11), doxycycline (DO) (n=4) and tetracycline (T) (n=5). None of the isolates was resistant to imipenem, amoxicillin/clavulanic acid, vancomycin (IPM, AMC, VA). However, multiple antimicrobial resistance was found to be 26.7%. The results of this study revealed the importance of isolated methicillin-resistant staphylococci in the stations with densely active human population and traffic, for public health. As a result, the importance of resting along known shorelines, where culturable airborne bacteria concentrations are much lower, and its importance for human health have been emphasized.
Go to article

This page uses 'cookies'. Learn more