Gene function adjustment for carbohydrate metabolism and enrichment of rumen microbiota with antibiotic resistance genes during subacute rumen acidosis induced by a high-grain diet in lactating dairy cows

Author(s):  
Y.Y. Mu ◽  
W.P. Qi ◽  
T. Zhang ◽  
J.Y. Zhang ◽  
S.Y. Mao
2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Mobin Rezanejad ◽  
Sepideh Karimi ◽  
Hassan Momtaz

Abstract Background Trueperella pyogenes is one of the most clinically imperative bacteria responsible for severe cases of mastitis and metritis, particularly in postpartum dairy cows. The bacterium has emergence of antibiotic resistance and virulence characters. The existing research was done to apprise the phenotypic and genotypic evaluation of antibiotic resistance and characterization of virulence factors in the T. pyogenes bacteria of bovine mastitis and metritis in postpartum cows. Methods Two-hundred and twenty-six bovine mastitic milk and 172 uterine swabs were collected and transferred to laboratory. Samples were cultured and T. pyogenes isolates were subjected to disk diffusion and DNA extraction. Distribution of virulence and antibiotic resistance genes was studied by PCR. Results Thirty-two out of 226 (14.15%) mastitic milk and forty-one out of 172 (23.83%) uterine swab samples were positive for T. pyogenes. Isolates of mastitic milk harbored the highest prevalence of resistance toward gentamicin (100%), penicillin (100%), ampicillin (90.62%), amoxicillin (87.50%) and trimethoprim-sulfamethoxazole (87.50%), while those of metritis harbored the highest prevalence of resistance toward ampicillin (100%), amoxicillin (100%), gentamicin (97.56%), penicillin (97.56%) and cefalexin (97.56%). AacC, aadA1, aadA2 and tetW were the most generally perceived antibiotic resistance genes. All bacteria harbored plo (100%) and fimA (100%) virulence factors. NanP, nanH, fimC and fimE were also the most generally perceived virulence factors. Conclusions All bacteria harbored plo and fimA virulence factors which showed that they can use as specific genetic markers with their important roles in pathogenicity of T. pyogenes bacteria. Phenotypic pattern of antibiotic resistance was confirmed by genotypic characterization of antibiotic resistance genes.


2016 ◽  
Vol 1 (2) ◽  
pp. 22 ◽  
Author(s):  
Navindra Kumari Palanisamy ◽  
Parasakthi Navaratnam ◽  
Shamala Devi Sekaran

Introduction: Streptococcus pneumoniae is an important bacterial pathogen, causing respiratory infection. Penicillin resistance in S. pneumoniae is associated with alterations in the penicillin binding proteins, while resistance to macrolides is conferred either by the modification of the ribosomal target site or efflux mechanism. This study aimed to characterize S. pneumoniae and its antibiotic resistance genes using 2 sets of multiplex PCRs. Methods: A quintuplex and triplex PCR was used to characterize the pbp1A, ermB, gyrA, ply, and the mefE genes. Fifty-eight penicillin sensitive strains (PSSP), 36 penicillin intermediate strains (PISP) and 26 penicillin resistance strains (PRSP) were used. Results: Alteration in pbp1A was only observed in PISP and PRSP strains, while PCR amplification of the ermB or mefE was observed only in strains with reduced susceptibility to erythromycin. The assay was found to be sensitive as simulated blood cultures showed the lowest level of detection to be 10cfu. Conclusions: As predicted, the assay was able to differentiate penicillin susceptible from the non-susceptible strains based on the detection of the pbp1A gene, which correlated with the MIC value of the strains.


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