At least 30 extended-spectrum beta-lactamases (ESB) have emerged responsible for resistance to indigestible beta-lactams (C3G) since their discovery in West Germany in 1983. Most of them are produced by enterobacteria and essentially K. pneumoniae which appeared susceptible to oxyimino-beta-lactams. A double-disk test was useful to detect such nosocomial isolates of enterobacteria (urines, bloo...

BACKGROUND Antimicrobial resistance within bacteria continues to present therapeutic challenges. One presumed risk factor for increased rates of resistance is prior exposure to antimicrobial drugs. OBJECTIVES To examine the impact of time since most recent exposure, the number of prior antimicrobial exposures and duration of use on antimicrobial resistance rates in Staphylococcus pseudinterme...

During treatment of infections with antibiotics in critically ill patients in the intensive care resistance often develops. This study aims to establish whether under those conditions this resistance can develop de novo or that genetic exchange between bacteria is by necessity involved. Chemostat cultures of Pseudomonas aeruginosa were exposed to treatment regimes with ceftazidime and meropenem...

In this study, it was aimed to investigate the presence of Klebsiella pneumoniae and phenotypically carbapenemase, extended-spectrum β-lactamase (ESBL), acquired-AmpC beta-lactamase, multiple antibiotic resistance isolates in faeces budgerigars parrots. A total 96 faecal samples belonging 54 42 parrots were used study. Cultivation performed on various media for identification pneuomiae from col...

The inactivation of ampD in Pseudomonas aeruginosa leads to a partially derepressed phenotype, characterized by a moderately high level basal ampC expression that is still further inducible, due to the presence of two additional ampD genes in this species (ampDh2 and ampDh3). The sequential inactivation of the three ampD genes was shown to lead to a stepwise upregulation of ampC expression, rea...

The common practice in antibacterial drug development has been to rapidly make an attempt to find ever-more stable and broad-spectrum variants for a particular antibiotic, once a drug resistance for that antibiotic is detected. We are now facing bacterial resistance toward our clinically relevant antibiotics of such a magnitude that the conversation for antimicrobial drug development ought to i...

We described plasmid mediated transfer of resistance to beta-lactam antibiotics between Bacteroides fragilis strains. Ampicillin-resistance was transferred from B. fragilis strain GAI-10150 to a B. fragilis strain JC-101 with a frequency of 10(-6)/input donor by a filter mating technique. A common plasmid band, named pBFKW1, was found in both the donor and the transconjugants. The plasmid was p...

Ceftobiprole is a new cephalosporin that exhibits a high level of affinity for methicillin-resistant Staphylococcus aureus PBP 2a. It was reported that ceftobiprole did not interact with a mutated form of the low-affinity protein Enterococcus faecium PBP 5 (PBP 5fm) that, when overexpressed, confers a beta-lactam resistance phenotype to the bacterium. Our results show that ceftobiprole binds to...

A chromosome-encoded beta-lactamase gene from Shewanella algae clinical isolate KB-1 was cloned and expressed in Escherichia coli. It encoded the Ambler class D enzyme OXA-55, sharing less than 55% identity with any other oxacillinases. Although conferring a narrow-spectrum beta-lactam resistance phenotype, OXA-55 had carbapenem-hydrolyzing activity that mirrored the reduced susceptibility to i...