ABSTRACT
italic>Dendrobium officinale Kimura et Migo is a rare Chinese herbal medicine, while Dendrobium crepidatum Lindl is a local medicine in Yunnan, both of which have the function of nourishing yin and stomach. To reveal the differences in chemical composition between the two species, ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF-MS/MS) was used to analyze the chemical composition of stems and leaves of D. officinale and D. crepidatum. Principal component analysis (PCA) and partial least squares discriminant analysis (OPLS-DA) were used to determine the differences in metabolites between species and parts of Dendrobium. Fifty-eight chemical compounds were identified in the two species. Analysis indicated that the side ring of alkaloids connected with nitrogen was readily cleaved during analysis. The results of PCA analysis showed that the stems and leaves of D. officinale and D. crepidatum could be easily differentiated, and the chemical constituents of D. officinale and D. crepidatum were significantly different. OPLS-DA analysis showed that there were 16 metabolite differences between the stems and 22 differences in metabolites between the leaves of D. officinale and D. crepidatum. The main metabolite differences in components between the two Dendrobium species were dendrocrepidine B, dendrocrepidine C and dendrocrepine. There were 14 differences in metabolites between the stems and leaves of D. crepidatum. In conclusion, the chemical compositions of D. officinale and D. crepidatum are quite different; the small molecular compounds of D. officinale are mainly terpenoids and flavonoids, and the content of alkaloids is low. There is no significant difference between stem and leaf. In contrast, D. crepidatum is mainly composed of alkaloids and terpenoids, with crepidamine and dendrocrepine as its unique components, and there are great differences in the components between stems and leaves. This study provides a theoretical basis for the development and utilization of Dendrobium resources.
ABSTRACT
<p><b>OBJECTIVE</b>To assess the bacterial profile and pattern of antibiotic resistance of urinary tract infections (UTIs) pathogens and to determine its clinical impact on management.</p><p><b>METHODS</b>Midstream urine samples were submitted for culture from 1998 to 2002, and 798 isolates were obtained for antimicrobial susceptibility testing including amikacin (AMK), ampicillin (AMP), cefzolin (CFZ), cefuroxime (CXM), ceftriaxone (CRO), ceftaxime (CTX), ceftazidime (CAZ), nalidixoc acid (NAL), ciprofloxacin (CIP), trimethoprim/sulfamethoxazole (SXT), nitrofurantoin (NIT) for Gram-negative bacteria and oxcillin (OXA), ampicillin (AMP), cefzolin (CFZ), ciprofloxacin (CIP), gentamicin (Gen), vancomycin (VAN), trimethoprim/sulfamethoxazole (SXT), nitrofurantoin (NIT) for Gram-positive cocci. beta-lactamases and ESBLs were tested when needed.</p><p><b>RESULTS</b>Enterobacteriaceae was the most frequently isolated pathogen. Among all the isolates, Escherichia coli accounted for 66.0%, followed by Enterococcus (6.5%), Klebsiella spp. (6.0%), Staphylococcus (5.4%). High resistance rates to CIP (56.0%), SXT (67.0%) and AMP (78.9%) were observed among the E. coli. CIP-resistant E. coli strains are being isolated with increasing frequency. From 1998 to 2002 the incidence of CIP-resistant increased steadily from 46.6% to 59.4%. A higher resistance rate to NAL was apparent. In contrast, NIT displayed a resistance rate of 8.9%, and AMK 4.9%. The ESBLs positive rate was 12.9% among the E. coli and 33.3% among the Klebsiella spp. respectively. A high resistance rate to CIP was also observed among the Staphylococcus (38.1%), Enterococcus (61.5%) and Streptococcus (85.0%), and the beta-lactamases positive rate was 95.2% among the Staphylococcus, but a lower resistance rate to NIT among Staphylococcus (2.4%) and Enterococcus (11.5%).</p><p><b>CONCLUSIONS</b>Resistance rates among common uropathogens continue to evolve and appear to be increasing to many commonly used agents especially to quinolones. Continued surveillance of resistance rates among uropathogens is needed to ensure appropriate recommendations for the treatment of the infections. Currently, the most appropriate agent for the empirical management of UTIs seems to be nitrofurantoin.</p>