Bovine mastitis caused by Staphylococcus aureus is difficult to treat because of increasing resistance against antibiotics, especially penicillin. β-Lactamase and biofilm are responsible for penicillin resistance of ...Bovine mastitis caused by Staphylococcus aureus is difficult to treat because of increasing resistance against antibiotics, especially penicillin. β-Lactamase and biofilm are responsible for penicillin resistance of S. aureus. The aim of this study was to investigate the β-lactamase activity and biofilm formation capacity of 37 penicillin-resistant S. aureus strains （35 were blaZ positive and 2 were blaZ negative） from bovine mastitis in Gansu Province, China, as well as to measure the intercellular adhesion genes icaA and icaD of these strains. β-Lactamase Test Kit was used to determine the β-lactamase activity, biofilm formation was tested by semi-quantitative adherence assay method. Moreover, the presence of icaA and icaD were measured by PCR. A total of 32 penicillin-resistant S. aureus strains, including the two blaZ-negative strains, were identified as β-lactamase producers. All tested S. aureus isolates produced biofilm in the microtiter plate assay. Meanwhile, all these strains were PCR-positive for the ica locus, icaA and icaD. The study indicated high prevalence of β-lactamase activity, biofilm-forming capacity, and the ica genes among the penicillin-resistant S. aureus isolates, and implied that S. aureus resistant to penicillin was attributed to multiple mechanisms.展开更多
The aim of the study was to investigate the prevalence and characterization of extended-spectrum β-lactamase （ESBL）- producing Escherichia coli isolated from bovine mastitis cases in China. ChromID ESBL agar was us...The aim of the study was to investigate the prevalence and characterization of extended-spectrum β-lactamase （ESBL）- producing Escherichia coli isolated from bovine mastitis cases in China. ChromID ESBL agar was used to confirm ESBL-producing E. coli. PCR and DNA sequencing were employed to characterize the genotype of ESBL-producers. Antimicrobial susceptibility was measured by disc diffusion. Overall, 73 of 318 E. coli isolates （22.96％） were identified as ESBL-producers. Of these ESBL-producing E. coli, the prevalence of blaCTX-M and blaTEM-1 was 97.26 and 71.23％, respectively. The predominant CTX-M-type ESBL was CTX-M-15 （65.75％）, followed by CTX-M-14 （10.96％）, CTX-M-55 （9.59％）, CTX-M-64 （5.48％）, CTX-M-65 （4.11％） and CTX-M-3 （1.37％）. This study is the first report of CTX-M-64 and CTX-M-65 in E. coli isolated from bovine mastitis. Furthermore, 72 ESBL-producing E. coli isolates （98.63％） were found to be multidrug-resistance. This study noted high prevalence and rates of antimicrobial resistance of ESBL-producing E. coli isolates from bovine mastitis cases in China.展开更多
[ Objective] To observe effect of Chanfukang on vascular endothelial cells of postpartum cows with Oi deficiency and Blood stasis, and to explore the treatment mechanism of Chanfukang. [Method] A total of 58 cows were...[ Objective] To observe effect of Chanfukang on vascular endothelial cells of postpartum cows with Oi deficiency and Blood stasis, and to explore the treatment mechanism of Chanfukang. [Method] A total of 58 cows were assigned to four groups. The cows in group 1 and group 2 suffered from Qi deficiency and Blood stasis. The cows in group 1 were gavaged with Chanfukang （0.5 g/kg-BW, 5 d） at 12 h post partum, but the cows in group 2 were not treated. The cows in group 3 were healthy and gavaged with Chanfukang （0.4 g/kg.BW, 5 d） at 12 h post partum. Cows in group 4 were healthy control cows. The plasma endothelin （ET） concentration and serum nitric oxide （NO） concentration were determined before and after parturition, respectively. [ Result ] The plasma ET concentration and serum NO concentration were significantly higher in the cows with Qi deficiency and Blood stasis than in the healthy control cows （P 〈 0.05）. The NO concentration decreased on Day 10 post partum in the cows with Qi deficiency and Blood stasis, but it was still higher than that in the healthy control cows. After taking Chanfukang for 7 d, the ET concentration and NO concentration decreased, and no significant difference was found between the cows with Qi deficiency and Blood stasis treated with Chanfukang and the healthy control cows. [ Conclusion] Chanfukang may relieve Qi deficiency and Blood stasis of postpartum cows through decreasing plasma ET concentration and serum NO concentration.展开更多
基金supported by the Central Public-Interest Scientific Institution Basal Research Fund,China(1610322015007)the Key Technologies R&D Program of China during the 12th Five-year Plan period(2012BAD12B03)the Natural Science Foundation of Gansu Province,China(145RJYA311)
文摘Bovine mastitis caused by Staphylococcus aureus is difficult to treat because of increasing resistance against antibiotics, especially penicillin. β-Lactamase and biofilm are responsible for penicillin resistance of S. aureus. The aim of this study was to investigate the β-lactamase activity and biofilm formation capacity of 37 penicillin-resistant S. aureus strains （35 were blaZ positive and 2 were blaZ negative） from bovine mastitis in Gansu Province, China, as well as to measure the intercellular adhesion genes icaA and icaD of these strains. β-Lactamase Test Kit was used to determine the β-lactamase activity, biofilm formation was tested by semi-quantitative adherence assay method. Moreover, the presence of icaA and icaD were measured by PCR. A total of 32 penicillin-resistant S. aureus strains, including the two blaZ-negative strains, were identified as β-lactamase producers. All tested S. aureus isolates produced biofilm in the microtiter plate assay. Meanwhile, all these strains were PCR-positive for the ica locus, icaA and icaD. The study indicated high prevalence of β-lactamase activity, biofilm-forming capacity, and the ica genes among the penicillin-resistant S. aureus isolates, and implied that S. aureus resistant to penicillin was attributed to multiple mechanisms.
基金funded by the National Key R&D Program of China (2017YFD0502200)the Central PublicInterest Scientific Institution Basal Research Fund,China (1610322017013)
文摘The aim of the study was to investigate the prevalence and characterization of extended-spectrum β-lactamase （ESBL）- producing Escherichia coli isolated from bovine mastitis cases in China. ChromID ESBL agar was used to confirm ESBL-producing E. coli. PCR and DNA sequencing were employed to characterize the genotype of ESBL-producers. Antimicrobial susceptibility was measured by disc diffusion. Overall, 73 of 318 E. coli isolates （22.96％） were identified as ESBL-producers. Of these ESBL-producing E. coli, the prevalence of blaCTX-M and blaTEM-1 was 97.26 and 71.23％, respectively. The predominant CTX-M-type ESBL was CTX-M-15 （65.75％）, followed by CTX-M-14 （10.96％）, CTX-M-55 （9.59％）, CTX-M-64 （5.48％）, CTX-M-65 （4.11％） and CTX-M-3 （1.37％）. This study is the first report of CTX-M-64 and CTX-M-65 in E. coli isolated from bovine mastitis. Furthermore, 72 ESBL-producing E. coli isolates （98.63％） were found to be multidrug-resistance. This study noted high prevalence and rates of antimicrobial resistance of ESBL-producing E. coli isolates from bovine mastitis cases in China.
基金funded by the grants from the National Technologies R&D Programme (2002BA518A04)
文摘[ Objective] To observe effect of Chanfukang on vascular endothelial cells of postpartum cows with Oi deficiency and Blood stasis, and to explore the treatment mechanism of Chanfukang. [Method] A total of 58 cows were assigned to four groups. The cows in group 1 and group 2 suffered from Qi deficiency and Blood stasis. The cows in group 1 were gavaged with Chanfukang （0.5 g/kg-BW, 5 d） at 12 h post partum, but the cows in group 2 were not treated. The cows in group 3 were healthy and gavaged with Chanfukang （0.4 g/kg.BW, 5 d） at 12 h post partum. Cows in group 4 were healthy control cows. The plasma endothelin （ET） concentration and serum nitric oxide （NO） concentration were determined before and after parturition, respectively. [ Result ] The plasma ET concentration and serum NO concentration were significantly higher in the cows with Qi deficiency and Blood stasis than in the healthy control cows （P 〈 0.05）. The NO concentration decreased on Day 10 post partum in the cows with Qi deficiency and Blood stasis, but it was still higher than that in the healthy control cows. After taking Chanfukang for 7 d, the ET concentration and NO concentration decreased, and no significant difference was found between the cows with Qi deficiency and Blood stasis treated with Chanfukang and the healthy control cows. [ Conclusion] Chanfukang may relieve Qi deficiency and Blood stasis of postpartum cows through decreasing plasma ET concentration and serum NO concentration.
