conclusions this study was the first report of the emergence of the plasmid-encoded blaoxa genes among e. cloacae isolates in iran. these findings highlight the need to use appropriate infection control policy and rational antibiotic therapy to reduce further spread of these resistant bacteria in the studied hospitals. results in total, 48 esbl-producing isolates (58.5%) were positive for the b...

Inactivation of β-lactam antibiotics by resistant bacteria is a 'cooperative' behavior that may allow sensitive bacteria to survive antibiotic treatment. However, the factors that determine the fraction of resistant cells in the bacterial population remain unclear, indicating a fundamental gap in our understanding of how antibiotic resistance evolves. Here, we experimentally track the spread of...

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 ...

Yersiniosis caused by Yersinia enterocolitica has been reported from all continents. The bacterial species is divided into more than fifty serovars and six biovars viz. 1A, 1B, 2, 3, 4 and 5 which differ in geographical distribution, ecological niches and pathogenicity. Most Y.enterocolitica strains harbor chromosomal genes for two β-lactamases, blaA an Ambler class A penicillinase and blaB an ...