The Preparatory Study On The Mechanism Of Shigellae From Chicken Resistance To β-lactam Antibiotics

This paper studied the relatianships among multi-drug- risistance of shigellae that producing Extended-spectram-β-lactamase(ESBLs), the resistance plasmid and the ESBLs.The mechanism of Shigellae resistance to β -lactam antibiotics and the transformation methods of resistance plasmid through different bacterisas in controlling conditions had been discussed.The theoretical evidence for choosing drugs rationally in clinical veterinarian,searching effective antibiotics for this bacteria and evaluating the ability of anibbiotics resistance to enzyme had been provided.The theoretical foundation for following resistance researches had been made.The contents of this paper mainly included four parts:detection the minimal inhibitory concentration(MIC) of the standard Shigellae and the clinical Shigellae,resistant inducement of Shigellae and detection the β -lactamase it producing, plasmid-transform and plasmid-combination of the induced resistant strains, detection the MIC and β -lactam of the transfer and the combiner.The MIC results of 17 common clinical using antibiotics to standard Shigellae and separate strains shows:standard Shigellae shows high sensitivity to all the antibiotics, comparing with standard shigellae, the two clinical strains sensitivity to Amoxicillin/Clavulanic Acid, Gentamicin, Amikacin, but judging by the reisistance standard(NCCLS), they have resistance to Amoxicilli Ampicillin Ampicillin/Sulbactam(2:l 4:1 8:1) ,quinolones(Ciprofloxacin Ofloxacin Gatifloxacin) Oxacillin the first generation cephalosporins(Cefalexin Cefazolin), the third generation cephalosporins(Ceftriaxone Ceftiafur Cefotaxime).The MIC results of 13 common clinical using antibiotics (Amoxicillin . Ampicillin etc) to the standard Shigellae which induced to 5 10 15 20 25 30 genetations shows: the value of MIC is increasing as the inducing was enhanced, the both two are positive correlation.The MIC results of 20 common clinical using antibiotics to standard Shigellae,clinical strains and their 30 generations inducing strains shows: standard Shigellae shows high sensitivity to all the 20 antibiotics, clinical strain shows moderate sensitivity to them.To the induced strains, it not only resistance to β -lactam antibiotics(Amoxicilli Ampicillin). the first generation cephalosporins(Cefalexin Cefazolin) the third generation cephalosporins(Ceftriaxone Ceftiafur Cefotaxime) ,but also resistance to quinolones(Ciprofloxacin Ofloxacin Gatifloxacin aminoglycosides(Gentamici Amikacin), both the standaed Shigellae and the clinical Shigellae, after it to be induced 30 generation,the value of MIC exceed 4 times than theirs before inducing. Combine with the β -lactamase...