The bla(TEM-1) beta-lactamase gene has become widespread due to the selective pressure of beta-lactam use and its stable maintenance on transferable DNA elements. In contrast, bla(SME-1) is rarely isolated and is confined to the chromosome of carbapenem-resistant Serratia marcescens strains. Dissemination of bla(SME-1) via transfer to a mobile DNA element could hinder the use of carbapenems. In...

Extended-spectrum β-lactamase (ESBL) production is an important resistance mechanism among clinical isolates of Enterobacter cloacae. TEM, SHV, and CTX-M are the most common ESBL genotypes among Enterobacter spp. The main aims of this study were to determine the antimicrobial susceptibility pattern and to detect ESBL-encoding genes as well as intI1 genes. One hundred twenty isolates of E. cloac...

OBJECTIVE The aim of this study was to explore the occurrence and molecular characterization of extended-spectrum β-lactamases (ESBL), plasmid-mediated AmpC β-lactamase (pAmpC) and carbapenemases among ESBL-producing multidrug resistant (MDR) Escherichia coli from dogs and cats in the United States. METHODS Of 2443 E.coli isolated from dogs and cats collected between August 2009 and January 2...

Ampicillin-sulbactam is commonly used as an empirical therapy for invasive infections where Escherichia coli is a potential pathogen. We evaluated the clinical and microbiologic characteristics of bloodstream infection due to E. coli, with focus on cases that were nonsusceptible to ampicillin-sulbactam and not producing extended-spectrum β-lactamase (ESBL). Of a total of 357 unique bacteremic c...

OBJECTIVES To investigate the occurrence and the diversity of Ambler class A ESBLs among Enterobacteriaceae from different Portuguese clinical settings over a 2 year period (2002-04). METHODS One hundred and nine extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae isolates from five geographically distant health institutions in Portugal were studied. ESBLs were characterized ...

BACKGROUND KPC carbapenemase-producing Klebsiella pneumoniae isolates have been increasingly detected in Europe. We report the first KPC-producing isolates characterized in Madrid, Spain. METHODS Twelve K. pneumoniae isolates recovered from clinical and surveillance cultures from eight patients (September 2009 to February 2010) that were resistant to carbapenems and resulted in a positive mod...

BACKGROUND Antibiotic resistance is widespread among diarrheagenic Escherichia coli in developing countries, where the overuse of antibiotics is common. Information regarding β-lactamases, especially Extended-Spectrum β-Lactamases (ESBLs) in diarrheagenic pathogens should be considered in clinical management when an optimal treatment is needed. OBJECTIVES The main objective of this study was ...

background :   this study was to evaluate the prevalence of ctx-mand tem type esbls-producing k. pneumoniae and determination of mdr, xdr, and pdr phenotypes of these isolates as well as find out the genetic relationship and molecular typing of these isolates using phenotypic and genotypic methods. methods :   non-repetitive 96 k. pneumonia isolates were isolated from hospitalized patients in a...

The mechanisms of antimicrobial resistance were characterized in 90 Salmonella enterica isolates either resistant or with intermediate resistance to amoxicillin/clavulanate (AMC(R/I)) or resistant to third-generation cephalosporins (C3G(R)). These isolates were recovered in three Spanish hospitals during 2007-2009. The C3G(R) phenotype was expressed by three isolates that carried the following ...