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Chemoenzymatic Approaches towards (S)-Duloxetine
Published in Peter Grunwald, Pharmaceutical Biocatalysis, 2019
Danish Shahzad, Muhammad Faisal, Aamer Saeed
The ketone-reductase ChKRED15 from the genome (genetic material of an organism) of Chryseobacterium sp. CA49 is expressed in E. coli. Ren et al. successfully employed this Chryseobacterium sp. CA49 to catalyze the reduction process of four important intermediates of (S)-duloxetine (i.e., 7, 22c, 34 and 37) to the respective (S)-alcohols (i.e., 9a, 22b, 35 and 36) with excellent enantioselectivity (>99%) (Ren et al., 2015). A single mutation, S12G, could improve the conservative G-rich entity, which enhanced the stability and catalytic potency of the enzyme (Scheme 5.14). Hence, when this mutant cooperate with a co-factor recycling system, complete transformation of N-methyl-3-oxo-3-(2-thienyl)propenamide 37 and ethyl 3-oxo-3-(2-thienyl)propanoate 34 are achieved within 24 and 6 h at substrate concentrations of 50 and 10 g/L, respectively, without loss of enantioselectivites (Scheme 5.14). For 31 and 32a, none of the six enzymes was able to catalyze the reduction process, which may be attributed to the powerful electron-donating effect of the β-amine moiety (Ren et al., 2015). Synthesis of (S)-duloxetine precursors via recombinant ketoreductase.
Ceftazidime and Ceftazidime–Avibactam
Published in M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson, Kucers’ The Use of Antibiotics, 2017
In regard to other aerobic Gram-negative bacilli, the following percentage of ceftazidime susceptibility have been recorded: Aeromonas spp., 95%; Agrobacterium spp. 28%; Alcaligenes spp., 84%; Chryseobacterium spp., 43%; Comamonas spp., 100%; Ochrobactrum anthropi, 11%; Ralstonia pickettii, 33%; and Sphingomonas paucimobilis, 71% (Sader et al., 2005b).
Chryseobacterium bacteraemia: a single-centre case series
Published in Infectious Diseases, 2018
Justo Sandino Pérez, Ana Maria Mancilla, Edgar Pérez Barragán, Mario Fernández-Ruiz
Bloodstream infection due to Chryseobacterium spp. remains uncommon in our institution during the 10-year period encompassed by this study, as confirmed by the low incidence rates reported. Some of the largest series of C. indologenes bacteraemia come from Eastern Asia [2–4,6], pointing to some degree of geographical variation in incidence. An emerging trend in Western countries has been recently suggested [7]. Although C. meningosepticum (currently renamed as E. meningoseptica) is often involved in nosocomial outbreaks in neonatal intensive care units [8], such an association has not been reported for C. indologenes and no case clustering was observed in our series. Chryseobacterium is ubiquitous in nature and, due to its resistance to chlorination, may be found on humid surfaces in hospital environments and indwelling devices containing fluids, such as CVCs or tracheostomy tubes [4,9]. Despite its low intrinsic virulence, C. indologenes may cause life-threatening infections in patients with debilitating conditions, as exemplified by the high mean age and noteworthy prevalence of underlying cancer (with two cases of pancreatic adenocarcinoma) and previous hospitalization observed in our experience. Previous use of broad-spectrum antibiotics and the presence of intravascular catheters also play a contributing role, particularly in view of the capacity for biofilm formation showed by C. indologenes [10]. Nevertheless, no comorbidity burden or apparent immunosuppression was noted in two of the reported cases, in which the intravenous catheter was considered as the presumed source of infection.