Decline in extractable kitasamycin during the composting of kitasamycin manufacturing waste with dairy manure and sawdust.

The aim of this study was to propose a feasible treatment of kitasamycin manufacturing waste by examining extractable kitasamycin and evaluating its compost maturity during the composting of waste with different ratios of dairy manure and sawdust over a 40-day period (volume/volume/volume; M1, 0/80/20; M2, 10/70/20; and M3, 30/50/20). During composting, the concentration of extractable kitasamycin in kitasamycin-contaminated composts declined rapidly, and was undetectable in M2 within 15 days. M2 also achieved the highest fertility compost, which was characterised by the following final parameters: electrical conductivity, 2.34 dS cm(-1); pH, 8.15; total C/N, 22.2; water-soluble NH4(+), P, and K, 0.37, 3.43, and 1.05 g kg(-1), respectively; and plant germination index values, 92%. Furthermore, DGGE analysis showed a dramatic increase in the diversity of bacterial species during composting. In contrast, a high concentration (121 mg kg(-1)) of extractable kitasamycin still remained in the M3 compost, which exerted an inhibitory effect on the composting, resulting in reduced bacterial diversity, high values of electrical conductivity and water-soluble NH4(+), a low C/N ratio, and a low plant germination index value. Furthermore, 3.86 log (CFU g(-1)) kitasamycin-resistant bacteria were still present on day 40, indicating the biological degradation contributed to the decline of extractable kitasamycin.

Sample preparation strategy for the simultaneous determination of macrolide antibiotics in animal feedingstuffs by liquid chromatography with electrochemical detection (HPLC-ECD).

A novel and suitable clean-up method that allows, for the first time, the simultaneous determination of a rather large number of macrolide antibiotics (erythromycin, rosamicin, spiramycin, tylosin, kitasamycin and josamycin in feedingstuffs by high performance liquid chromatography with electrochemical detection (HPLC-ECD) is presented in this work. The effectiveness of the developed clean-up method allows the quantification of the target macrolides in poultry feed using standard calibration curves instead of matrix matched standards, which overcomes the general problem of finding representative blanks. Furthermore an additional back extraction included in the sample preparation procedure allows the determination of an additional macrolide (oleandomycin) with detection limits, expressed as apparent concentration in poultry feed, ranging from 0.04 to 0.22 mg kg(-1) and relative standard deviation values ranging from 3.6 to 10.1% depending on the target analyte. Moreover, this additional step has been proven to enlarge the scope of the method by the extension of its applicability, at the target level of concentration, to other animal feedingstuffs such as pig and cattle. The analysis of real feedingstuffs containing macrolides demonstrated the fitness for purpose of the whole analytical procedure as well as a good fitting between real and spiked samples. The proposed methods appeared therefore as a sound alternative in the frame of control (e.g. for post-screening purposes) and/or monitoring surveillance programmes at the target level of 1.0 mg kg(-1) established according to the reported lowest dosage of additive needed to lead a growth promoting effect.

[Identification of the components and products of hydrolysis in acetylleucomycin by LC-MS].

AIM: To identify the components of acetylleucomycin and its hydrolytic products by LC-MS. METHODS: Acetylleucomycin was separated on a Diamonsil C18 column with 0.1 mol x L(-1) ammonium acetate-acetontrile (35 : 65) as mobile phase. The LC-MS was equipped with an electorspray ion source (ESI), which was set at the positive ion mode, and the mass spectra of each component in chromatogram were obtained with difference cone voltage. RESULTS: The components of acetylleucomycin and its hydrolytic products can be separated by HPLC. The components were identified according to the molecular weight and its major mass fragment ions. The major components identified in domastic acetylleucomycin were acetylleucomycin A4, A5; acetylleucomycin A1, A3; acetylleucomycin A6, A7, and acetylleucomycin A13. The hydrolytic products of acetylleucomycin were not kitasamycin, but some non-complete hydrolytic product. CONCLUSION: The method is rapid, sensitive and specific. It' s suitable to application in the fields of multi-components antibiotics analysis.

Efficient synthesis of 9- and 13-oxo leucomycin derivatives using hypervalent iodine reagents in solution and on solid support.

An efficient procedure for the highly selective oxidation of leucomycines to the corresponding 16-membered 9- and 13-oxo macrolides using hypervalent iodinates is presented. Both the Dess-Martin periodinane (DMP) and polymer-bound 2-iodoxybenzoic acid (IBX) show clear advantages over the previously employed manganese dioxide. Key intermediates for a variety of further chemical derivatization methods (2a, 2b) are obtained in very good yields without the requirement of protecting groups.