We investigated the occurrence of multidrug resistance in 44 Enterobacter aerogenes and Klebsiella pneumoniae clinical isolates. Efflux was involved in resistance in E. aerogenes isolates more frequently than in K. pneumoniae isolates (100 versus 38% of isolates) and was associated with the expression of phenylalanine arginine beta-naphthylamide-susceptible active efflux. AcrA-TolC overproducti...

Escherichia coli, and presumably most other gram-negative bacteria, possesses an efficient protein machinery for recycling its peptidoglycan during cell growth. The major recycled peptidoglycan product is N-acetylglucosamine-1,6-anhydro-N-acetylmuramic acid-tetrapeptide. Its uptake from the periplasm into the cytoplasm is carried out via the AmpG protein, an intrinsic membrane protein. In gram-...

The expression of resistance to cephalosporins is highly varied and due to various mechanisms. The greatest disadvantage of the cephalosporins is that they are inactivated by the array of beta-lactamases produced by bacteria. The high levels of chromosomal enzymes produced by these organisms are a major cause of cephalosporin resistance. Plasmid-mediated beta-lactamases (PMBLs) have also been i...

BACKGROUND & OBJECTIVES AmpC β-lactamases are clinically significant since these confer resistance to cephalosporins in the oxyimino group, 7-α methoxycephalosporins and are not affected by available β-lactamase inhibitors. In this study we looked for both extended spectrum β-lactamases (ESBL) and AmpC β-lactamases in Klebsiella pneumoniae clinical isolates. METHODS One hundred consecutive, n...

We report the case of a pediatric patient with a Salmonella enterica serotype Infantis infection. Detailed microbiological investigation revealed that this isolate carries four beta-lactamase genes (bla(TEM-1b) variant, bla(SHV-5), bla(CTX-M-15), and bla(CMY-2)) conferring resistance to all beta-lactams but imipenem. This is the first report of a Salmonella isolate with CTX-M and AmpC enzymes o...