BACKGROUND Delayed-onset urticarial or maculopapular rashes are frequently observed in children treated with β-lactams. Many are labeled "allergic" without reliable testing. OBJECTIVE Determine the etiology of these rashes by exploring both infectious and allergic causes. METHODS Children presenting to the emergency department with delayed-onset urticarial or maculopapular rashes were enrol...

BACKGROUND There have been few studies regarding the cross-reactivity and tolerability of penicillins, aztreonam, and carbapenems in large samples of subjects with cephalosporin allergy. OBJECTIVE We sought to evaluate the possibility of using penicillins, monobactams, and carbapenems in subjects with cephalosporin allergy who especially require them. METHODS We conducted a prospective stud...

Burkholderia pseudomallei is the etiological agent of melioidosis. Because of the bacterium's intrinsic resistance and propensity to establish latent infections, melioidosis therapy is complicated and prolonged. Newer generation β-lactams, specifically ceftazidime, are used for acute phase therapy, but resistance to this cephalosporin has been observed. The chromosomally encoded penA gene encod...

A highly stereoselective trichlorosilane-mediated reduction of N-benzyl enamines was developed; the combination of a low cost, easy to make metal-free catalyst and an inexpensive chiral auxiliary allowed to perform the reaction on substrates with different structural features often with total control of the stereoselectivity. By easy deprotection through hydrogenolysis followed by conversion of...

Cyclohexane analogues of the antifungal icofungipen [(1R,2S)-2-amino-4-methylenecyclopentanecarboxylic acid] were selectively synthesized from unsaturated bicyclic β-lactams by transformation of the ring olefinic bond through three different regio- and stereocontrolled hydroxylation techniques, followed by hydroxy group oxidation and oxo-methylene interconversion with a phosphorane. Starting fr...

A two-step sequence for the synthesis of various 3,4-dihydro-2H-1,3-thiazines is presented. In the first step, 2H-1,3-thiazines were prepared by a new multicomponent reaction (MCR). Starting from β-chlorovinyl aldehydes, this MCR offers an efficient and facile access to 2,2-dialkyl- and 2-alkyl-2-aralkyl-5,6-diaryl-2H-1,3-thiazines. The potential of these products in subsequent reactions was ve...

Pseudomonas aeruginosa is a ubiquitous versatile environmental microorganism with a remarkable ability to grow under diverse environmental conditions. Moreover, P. aeruginosa is responsible for life-threatening infections in immunocompromised and cystic fibrosis patients, as the extraordinary capacity of this pathogen to develop antimicrobial resistance dramatically limits our therapeutic arsen...

TEM-154, identified in Portugal in 2004, associated the substitutions observed in the extended-spectrum β-lactamase (ESBL) TEM-12 and in the inhibitor-resistant penicillinase (IRT) TEM-33. This enzyme exhibited hydrolytic activity against ceftazidime and a low level of resistance to clavulanic acid. Surprisingly, the substitution Met69Leu enhanced the catalytic efficiency of oxyimino β-lactams ...

The opportunistic human pathogen Enterococcus faecium overproduces the low-affinity PBP5. In clinical strains, mutations in PBP5 further reduce its acylation rate by β-lactams. Previous studies have reported that ceftaroline had poor inhibitory activity against β-lactam-resistant E. faecium strains. In this study, we show that ceftaroline exhibits killing activity against our laboratory-derived...

A novel metallo-β-lactamase, NDM-8, was identified in a multidrug-resistant Escherichia coli isolate, IOMTU11 (NCGM37), obtained from the respiratory tract of a patient in Nepal. The amino acid sequence of NDM-8 has substitutions at positions 130 (Asp to Gly) and 154 (Met to Leu) compared with NDM-1. NDM-8 showed enzymatic activities against β-lactams similar to those of NDM-1.