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Objective To analysis the dissemination of integrons in the extended-spectrumβ-laetamases(ESBLs)producing Escherichia coli,isolated from stool specimen of chicken and to study the relations between the resistance and the integrons of these isolates.Methods The Escherichia coli isolates were collected from Gansu,Hubei,Sichuan provinces and Beijing municipal city，and were isolated from stool specimen of chickens.Using WHONET software,the Escherichia coli producing ESBLs were selected，and then detected by PCR method class 1,2,3,4 integrmse.PCR products of the variable region of the integron were sequenced.Results 54 of the 224(24.1％)isolates were ESBLs producing Escherichia coli.Class 1 integron were detected in 63.0％of the isolates,and aadAl,aadA2,aadA5,aadA22,dfrAl2,dfrA17,dfrI,aar-3 were found in the variable region and aad A gene encodes resistant to streptomycin，spectinomyein,dfr gene to trimethoprim and aar to rifampicin.We realized that aadA 22 was the first time detected in China.C1ass 2 integron were detected in 5.6％ of the isolates,Class 3 integron was detected in 3 isolates.Conclusion Class 1 integron Was the most commonly seen integron in Escherichia coli,encoding the resistance to streptomycin.spectinomycin and trimethoprim.Integrons were contributed to the horizontal transfer of resistant genes in the same or different species,suggesting that the antimicrobial resistance and the dissemination of integrons should be monitored.
ABSTRACT
A qualitative analysis method to identify related substances of rifampicin by correlation of spectra in chromatography was established. Standard chromatographic and spectral data obtained by high-performance liquid chromatography with diode array detection (HPLC-DAD) were developed and used in identification of peaks in samples by calculating correlation coefficients (R). The comparison of spectra was expanded to three-dimensional space. Peaks in chromatography can be identified accurately and rapidly through chromatographic system change. The identification results were validated by LC-MS. The threshold of R was set to 0.99 in order to discriminate the impurities and the minimal amount for identification was 30 ng. Taking full advantage of chromatographic separate efficiency and spectral exclusiveness, the method is accurate and reproducible as a new and effective way to identify multi-components in drugs.
Subject(s)
Chromatography, High Pressure Liquid , Methods , Hydrogen-Ion Concentration , Mass Spectrometry , RifampinABSTRACT
<p><b>AIM</b>To analyze if the response factors of different aminoglycoside antibiotics detected by evaporative light-scattering detector (ELSD) are the same. If they are, then ELSD can be applied to the quality analysis of this class of antibiotics.</p><p><b>METHODS</b>The response factors of five different aminoglycosides (amikacin, sisomicin, netilmicin, etimicin and vertilmicin) detected by ELSD were determined by using a Diamonsil C18 column (150 mm x 4.6 mm, 5 microns) as analytical column and 0.2 mol.L-1 trifluoroacetic acid-methanol (94:6) as mobile phase at a flow rate of 0.6 mL.min-1, the temperature of the drift tube was set at 110 degrees C, and the flow of carrier gas at 2.80 L.min-1. Detector responses (A) and the amount of injection of each substance (m) were fitted to the logarithmic regression: logA = blogm + loga.</p><p><b>RESULTS</b>The linear regression equation obtained were amikacin: Y = 1.46X + 5.07, gamma = 0.9997; sisomicin: Y = 1.51X + 5.03, gamma = 0.9997; netilmicin: Y = 1.52X + 4.88, gamma = 1.000; etimicin: Y = 1.46X + 4.85, gamma = 0.9999; vertilmicin: Y = 1.41X + 4.90, gamma = 0.9998. The differences between them were negligible.</p><p><b>CONCLUSION</b>Different aminoglycosides can give the same responses with ELSD detection. So, the HPLC-ELSD methods can be applied to the analysis of impurities, the control of the ratio of multi-components drug and the determination of new substances by using another substance as reference, etc.</p>
Subject(s)
Aminoglycosides , Anti-Bacterial Agents , Chromatography, High Pressure Liquid , MethodsABSTRACT
<p><b>AIM</b>To investigate whether tazobctam has crystallization water.</p><p><b>METHODS</b>In order to establish a method for water content determination in tazobctam, many methods including Karl Fischer titration, weight loss on drying, TGA, DSC and X-ray diffraction experiment of an orthorhombic form were studied.</p><p><b>RESULTS</b>The water content of the same batch tazobactam determined by different mthods was different.</p><p><b>CONCLUSION</b>The results showed that one mole tazobatam contains half mole water of crystallization and the strength of attraction between tazobatam molecule and water molecule is rather strong.</p>