BACKGROUND Gram-negative multidrug-resistant (MDR) bacteria are major causes of nosocomial infections, and antibiotic resistance in these organisms is often plasmid mediated. Data are scarce pertaining to molecular mechanisms of antibiotic resistance in resource constrained areas such as Iraq. METHODOLOGY/PRINCIPAL FINDINGS In this study, all MDR Enterobacteriaceae (n = 38) and randomly selec...

The effects of several plasmids, including cloning vectors and R factors, on the virulence of Vibrio cholerae CA401R were determined by measuring the dose-related diarrheal response in orally challenged infant mice. The plasmids were also examined for their effects on the colonization ability of strain CA401R by joint infection experiments with a spectinomycin-resistant CA401 strain as an inter...

The genome of the unicellular cyanobacterium Synechocystis sp. PCC 6803 consists of a single chromosome and several plasmids of different sizes, and the nucleotide sequences of the chromosome and three small plasmids (5.2 kb, 2.4 kb, and 2.3 kb) have already been sequenced. We newly determined the nucleotide sequences of four large plasmids, which have been identified in our laboratory (pSYSM:1...

The large repABC plasmids of the order Rhizobiales with Class I quorum-regulated conjugative transfer systems often define the nature of the bacterium that harbors them. These otherwise diverse plasmids contain a core of highly conserved genes for replication and conjugation raising the question of their evolutionary relationships. In an analysis of 18 such plasmids these elements fall into two...

INTRODUCTION............................................................ 211 Definitions.................................................................. 211 Overall Genetic Organization of aPlasmid. 212 RECOGNITION AND IDENTIFICATION OF EXTRACHROMOSOMAL ELEIMENTS............................................................. 212 Lack of Genetic Linkage to Chromosome................................

In both humans and animals, Clostridium perfringens is an important cause of histotoxic infections and diseases originating in the intestines, such as enteritis and enterotoxemia. The virulence of this Gram-positive, anaerobic bacterium is heavily dependent upon its prolific toxin-producing ability. Many of the ∼16 toxins produced by C. perfringens are encoded by large plasmids that range in si...

The dissemination of antimicrobial resistance genes in Enterobacteriaceae has been largely attributed to plasmids, circular DNA molecules capable of autonomous replication. Whereas high-copy-number plasmids primarily rely on passive diffusion for plasmid maintenance, low-copy-number plasmids utilize so-called partition (par) systems. Plasmid partition relies on three structures, i.e. a centrome...

Antibiotic resistance increases the likelihood of death from infection by common pathogens such as Escherichia coli and Klebsiella pneumoniae in developed and developing countries alike. Most important modern antibiotic resistance genes spread between such species on self-transmissible (conjugative) plasmids. These plasmids are traditionally grouped on the basis of replicon incompatibility (Inc...

Mobilome of hyperthermophilic archaea dwelling in deep-sea hydrothermal vents is poorly characterized. To gain insight into genetic diversity and dynamics of mobile genetic elements in these environments we have sequenced five new plasmids from different Thermococcus strains that have been isolated from geographically remote hydrothermal vents. The plasmids were ascribed to two subfamilies, pTN...

After a new transformation procedure, 10% of Saccharomyces cerevisiae cells were found to contain transforming DNA sequences. We used direct transfer of plasmid molecules by fusing bacterial minicell protoplasts to yeast protoplasts. Since the procedure significantly reduces the toxic effect of procaryotic protoplasm on the eucaryotic organism, it might be generally applicable in other systems ...