In a collection of 43 indole-positive Klebsiella clinical isolates, which were initially identified as Klebsiella oxytoca, there were 18 isolates which exhibited a pattern characteristic of extended-spectrum beta-lactamase (ESBL) resistance. This study aimed to confirm their identity by biochemical tests and by PCR and to determine the genetic basis for their resistance to the beta-lactams and ...

To evaluate the validity of our in vitro evolution method as a model for natural evolutionary processes, the TEM-1 beta-lactamase gene was evolved in vitro and was selected for increased resistance to cefotaxime, cefuroxime, ceftazadime, and aztreonam, i.e., the "extended-spectrum" phenotype. The amino acid substitutions recovered in 10 independent in vitro evolvants were compared with the amin...

Of 59 clinical isolates of Enterobacter cloacae from a teaching hospital in Sichuan, China, 18 isolates were shown to be resistant to oxyimino cephalosporins and aztreonam. Enterobacterial repetitive consensus PCR revealed that these isolates comprised 7 distinct genotypes. The presence of plasmids in the 18 clinical isolates was revealed by conjugational transfer of plasmids from E. cloacae to...

This study presents updates on molecular epidemiology of extended-spectrum beta-lactamases (ESBLs) in clinical isolates of Enterobacteriaceae from Srinagarind Hospital, Khon Kaen University, Thailand. All isolates were screened for the presence of ESBL genes, bla(TEM), bla(SHV), bla(VEB) and bla(CTX-M), using PCR followed by nucleotide sequence determination. The results revealed that beta-lact...

Pseudomonas aeruginosa is a common cause of surgical-site infections and healthcare-associated infections in the bloodstream, and urinary tract. Iron oxide nanoparticles (IONPs) have shown, to possess antibacterial features. The nanoparticles' status as emerging therapeutic elements has motivated investigators to assess the effects of iron nanoparticles on the expression of TEM type be...

beta-Lactamase production was investigated in cultures of 25 Klebsiella pneumoniae isolates isolated at a hospital in Durban, South Africa, in 1994 and 1996. Twenty of these isolates gave ceftazidime MIC/ceftazidime plus clavulanate MIC ratios of >/=8, implying production of extended-spectrum beta-lactamases (ESBLs), and DNA sequencing identified an ESBL gene (bla(TEM-53)) in a further two isol...