Prevalence of bacterial agents isolated from clinical cases of bovine mastitis in the dry period and the determination of their antibiotic sensitivity in Tabriz,Iran

Objective:To determine the prevalence of mastitis-causing bacteria in the dry period and its antibiotic sensitivity.Methods:In this study,852 dry cows were examined.A total of 30 cows with clinical mastitis symptoms were detected and their milk samples were collected.In order to purify the bacteria,brain heart infusion and blood agar media were applied and single colonies were used for Gram staining,oxidase and catalase testing,cultivating in O-F medium to determine the genus and species of bacteria.Then,antimicrobial susceptibility was tested by the agar disk diffusion method.Results:The prevalence of isolated bacteria was 2.46%,in which coagulase positive Staphylococcus,coagulase negative Staphylococcus,Streptococcus dysgalactiae,Streptococcus faecalis,Escherichia coli,Pseudomonas,Bacillus and yeast were(9/99)%,(6/66)%,(13/32)%,(3/33%),(6/66)%,(13/32)%,(9/99)%and(6/66)%,respectively.After tests of antibiotic susceptibility,the most and the least sensitivity were reported to enrofloxacin and ampicillin respectively.Conclusions:This study indicated that Streptococcus dysgalactiae is the most commonly isolated bacteria with the greatest sensitivity to enrofloxacin and tetracycline which can be used to treat mastitis in the dry period in Tabriz.

Physical-biological Collaborative Prevention and Control of Facility Strawberry Continuous Cropping Diseases

The aim was to develop green strawberry varieties,control soil-borne diseases from facility strawberry continuous cropping,improve the safety and quality of strawberries and promote the healthy and stable development of the strawberry industry. Based on the production practices in recent years,we summarized the physical-biological collaborative prevention and control technology for the disease of facility strawberry continuous cropping facilities,established the technical goals,the main types of soil-borne diseases,and the physical-biological collaborative control prevention and control technologies,mainly including the specific methods and technical points of solar high temperature disinfection technology and biological bacterial fertilizer（ agent） treatment technology.

Effects of cecropin-XJ on growth and adherence of oral cariogenic bacteria in vitro

Background CecropinXJ belongs to cecropinB, which is the most potent antibacterial peptide found naturally The aim of this study was to investigate the effects of cecropinXJ on growth and adherence of oral cariogenic bacteriaMethods Four oral cariogenic bacteria (Streptococcus mutans, Lactobacillus acidophilus, Actinomyces viscosus and Actinomyces naeslundii) were chosen for this experiment The minimal inhibitory concentrations (MICs) and reductive percent of bacterial growth were used to assay the antibacterial activity of cecropinXJ Mammalian cytotoxicity of cecropinXJ was tested with human periodontal membrane fibroblasts by tetrazolium (MTT) colorimetric assay The bacterial morphological changes induced by cecropinXJ were examined on scanning electron microscope (SEM) The influence of cecropinXJ on bacterial adhesion to salivacoated hydroxyapatite (SHA) was measured by scintillation countingResults The MICs of cecropinXJ for inhibition of the growth of four bacteria ranged from 40 to 428 μmol/L with the highest susceptible to A naeslundii and the lowest susceptible to L acidophilus At pH 68, 55 and 82, 1/2 MIC of cecropinXJ reduced the number of viable bacteria by 409%, 678% and 328% for S mutans and by 281%, 572% and 379% for L acidophilus The activities against Smutans and L acidophilus increased at pH 55 compared with pH 68 (P<001, respectively) In present of 50% saliva, 1/2 MIC of the peptide decreased the direct count of viable cells by 292% and 144% for S mutans and L acidophilus, respectively (P<001 and P>005, respectively), whereas almost no reduction counts were detected in the presence of 20% serum for both bacteria (P>005, respectively) Mammalian cytotoxicity of cecropinXJ from 10 to 100 μmol/L exhibited no cytotoxicity against human periodontal membrane fibroblasts (P>005) Bacterial morphological changes induced by MIC of cecropinXJ examined on SEM showed cell surface disruption Furthermore, the ability of A naeslundii adhesion to SHA decreased significantly with MIC of cecropinXJ for 10 and 20 minutes (P=0001 and 0000, respectively), and S mutans, A viscosus to SHA decreased significantly with MIC of cecropinXJ for 20 minutes( P=0000, respectively) Conclusions CecropinXJ exhibited bactericidal action against cariogenic pathogens, and the antibacterial activity enhanced in the acid environment The results also demonstrate that cecropinXJ prevents S mutans and actinomyces adsorption to SHA These findings suggest that CecropinXJ may have potential to prevent caries