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We herein report a case of Klebsiella oxytoca-producing IMP-1 that was detected as a first isolate of carbapenem-resistant Enterobacteriaceae (CRE) at our facility. Since K. oxytoca is an uncommon strain for CRE, we speculated that the resistant organism had already spread out inside the hospital. Metallo-β-lactamases promotes antibiotic resistance in Enterobacteriaceae, which potentially yields problematic issues in clinical settings. Active surveillance of antibiotic resistant strains is important and should be repeatedly highlighted. Furthermore, appropriate methods should be established to detect highly resistant strains.

A novel method for the extraction of inosinic acid in Smoked Katsuwonus pelamis based on water was developed. The inosinic acid was extracted by 95 degrees C water for 5 min. The subsequent analysis of inosinic acid was achieved on an Agilent Zorbax SB-C18 column (150 mm x 4.6 mm, 5 microm) with the mobile phase of methanol-50 mmol/L ammonium acetate (5: 95, v/v) at a flow rate of 1.0 mL/min at 30 degrees C. The detection wavelength was set at 254 nm. The results showed that the linear range for inosinic acid in Smoked Katsuwonus pelamis was between 1.0 mg/L and 120.0 mg/L with the limit of detection (LOD, S/N = 3) of 4 mg/kg and the limit of quantification (LOQ, S/N = 10) of 12 mg/kg. At the spiked levels of 0.40, 2.00, 4.00 g/kg (n = 3), the recoveries ranged from 84.6% to 100.2% with the relative standard deviations (RSDs) between 1.00% and 6.12%. Compared with traditional extraction method by perchloric acid, the extraction efficiency was improved by 37.0%. The novel method is safe, stable and accurate for the determination of inosinic acid in Smoked Katsuwonus pelamis, which can also be applied to the determination of inosinic acid in other foods and deserved to be spread.

A new method for the bonding of diethylamine(DEA) on the surface of silica to prepare novel hydrophilic packings for HPLC has been studied. After allyl glycidyl ether being synthesized, the Si-DEA anion-exchange bonded phase was prepared by the reaction of the double bond in allyl group with Si-H silica. The bonded phases obtained were characterized by elemental analysis, diffuse reflectance infrared Fourier transform(DRIFT) spectroscopy and HPLC evaluation. The methods were used for both porous silica and monodisperse non-porous silica. The contents of carbon, hydrogen and nitrogen of porous Si-DEA packing (MPS-DEA) were 3.31%, 0.95% and 1.34% respectively and those of monodisperse non-porous Si-DEA packing (NPS-DEA) were 2.55%, 0.97% and 0.96% respectively. The diethylamine absorption peak can be observed at 2970 cm-1 from the Si-DEA silica DRIFT spectrum. These data revealed that the diethylamine had been bonded on MPS-DEA and NPS-DEA packings. In HPLC tests, nucleotides and nucleosides such as cytosine, uracil, cytidine-5'-monophosphate, adenosine-5'-monophosphate, inosine-5'-monophosphate and guanosine-5'-monophosphate were satisfactorily separated on the porous anion-exchange packing (MPS-DEA), and a group of proteins (lysozyme, ribonuclease, ovalbumin, bovine serum albumin, insulin and gamma-globulin) were separated within 15 minutes successfuly. All test results indicated that the new method for preparing better anion-exchange silica packings is effective for both porous silica and monodiperse non-porous silica.