This study was undertaken to investigate drug resistance in Escherichia coli (E. coli) strains isolated from bamboo rats in Zhejiang province of China. One hundred and fifty-four E. coli strains were isolated from dead bamboo rats. Polymerase chain reaction (PCR) was used to detect the representative genes encoding resistance to commonly used β-lactam antibiotics. Highest resistance was observe...

OBJECTIVES To determine macrolide-lincosamide-streptogramin (MLS) resistance determinants in the Capnocytophaga genus and to describe the prevalence of β-lactam resistance genes in human oral Capnocytophaga species. METHODS Forty-eight Capnocytophaga isolates identified by analysis of 16S rRNA sequences were isolated from subgingival samples from 14 haematology patients (HPs), 11 periodontiti...

Fifteen novel β-lactams bearing the N-ethyl tert-butyl carbamate group 5a-o and fifteen N-(2-aminoethyl) β-lactams 6a-o were synthesized by the ketene-imine [2+2] cycloaddition reaction (Staudinger ). The cycloaddition reaction was found to be totally diastereoselective leading exclusively to the formation of the cis-β-lactam derivatives. These newly synthesized β-lactams were evaluated for the...

An evolution of antibiotic-resistant bacteria has resulted in the need for new antibiotics. β-Lactam based drugs are the most predominantly prescribed antibiotics to combat bacterial infections; however, production of β-lactamases, which catalyze the hydrolysis of the β-lactam bond of this class of antibiotics, by pathogenic bacteria such as Bacillus cereus, are rendering them useless. Some inh...

background: the presence of aflatoxin m1 (afm1) andantibiotic residues in milk and milk products is a public healthconcern. milk and milk powder have the potential forintroducing afm1 and antibiotic into human diet. in recentyears, milk powder has been used on a large scale in dairyfactories. consequently, antibiotic residues and aflatoxincontamination control in these products has gained impor...

Due to the emerging resistance against classical β-lactam-based antibiotics, a growing number of bacterial infections has become harder to treat. This alarming tendency necessitates continued research on novel antibacterial agents. Many classes of β-lactam antibiotics are characterized by the presence of the 3-aminoazetidin-2-one core, which resembles the natural substrate of the target penicil...

in this paper the synthesis of some new polyaromatic monocyclic β-lactams has been reported. these cycloadducts have been synthesized by the [2+2] ketene-imine cycloaddition reaction known as the staudinger reaction. all of the products have been fully characterized by ir, 1h-nmr, 13c-nmr, mass spectroscopy and elemental analyses. the x-ray crystal structure of a cis β-lactam has been also pres...

Urinary tract infections (UTIs) are among the most common diagnosed in clinical practice. Treatment is often initiated before microbiological confirmation and anti-microbial susceptibility testing. With rapidly rising antibiotic resistance treatment failures not uncommon. Beta-lactamase production by gram-negative bacteria causing UTI commonest mode of drug resistance. The aim current study was...

β-Lactams were diastereoselectively formed by the reaction of SF5-containing aldimines, or an SF5-containing ketimine, with benzyloxyketene in a conrotatory ring closure process. Imine formation and cyclization were possible in spite of the acidification of protons on the carbon bound to SF5. The reactions of the aldimines demonstrated very good 1,2-lk diastereoselectivity, however lack of ster...

A suitably protected Orn-derived (3S,4S)-β-lactam was used as common intermediate in the synthesis of conformationally constrained (3S,4S)-2-oxoazepane α,α- and (2S,3S)-2-oxopiperidine-β(2,3,3)-amino acid derivatives. Compared to alternative procedures using an N-p-methoxybenzyl group at the 2-azetidinone, the incorporation of a p-methoxyphenyl moiety is crucial for the excellent stereochemical...