Mechanism of Escherichia coli resistance to Pyrrhocoricin.

Due to their lack of toxicity to mammalian cells and good serum stability, proline-rich antimicrobial peptides (PR-AMPs) have been proposed as promising candidates for the treatment of infections caused by antimicrobial-resistant bacterial pathogens. It has been hypothesized that these peptides act on multiple targets within bacterial cells, and therefore the likelihood of the emergence of resistance was considered to be low. Here, we show that spontaneous Escherichia coli mutants resistant to pyrrhocoricin arise at a frequency of approximately 6 × 10(-7).

Implementation of evidence-based practice for a pediatric pain assessment instrument.

Purpose/objectives: The purpose of this project was to facilitate the successful implementation of an evidence-based practice (EBP) change to the Faces Pain Scale-Revised (FPS-R) using the Promoting Action on Research Implementation in Health Services (PARIHS) framework.

Background/rationale: Accurate pain assessment is a high priority in the clinical setting. Despite the availability of valid pain assessment instruments, use in practice remains deficient.

The use of high-throughput DNA sequencing in the investigation of antigenic variation: application to Neisseria species.

Antigenic variation occurs in a broad range of species. This process resembles gene conversion in that variant DNA is unidirectionally transferred from partial gene copies (or silent loci) into an expression locus. Previous studies of antigenic variation have involved the amplification and sequencing of individual genes from hundreds of colonies.

Attachment and invasion of Neisseria meningitidis to host cells is related to surface hydrophobicity, bacterial cell size and capsule.

We compared exemplar strains from two hypervirulent clonal complexes, strain NMB-CDC from ST-8/11 cc and strain MC58 from ST-32/269 cc, in host cell attachment and invasion. Strain NMB-CDC attached to and invaded host cells at a significantly greater frequency than strain MC58. Type IV pili retained the primary role for initial attachment to host cells for both isolates regardless of pilin class and glycosylation pattern.

Neisserial Correia repeat-enclosed elements do not influence the transcription of pil genes in Neisseria gonorrhoeae and Neisseria meningitidis.

Two human-specific neisserial pathogens, Neisseria gonorrhoeae and Neisseria meningitidis, require the expression of type IV pili (tfp) for initial attachment to the host during infection. However, the mechanisms controlling the assembly and functionality of tfp are poorly understood. It is known that the gonococcal pilE gene, encoding the major subunit, is positively regulated by IHF, a multifunctional DNA binding protein.

Ecf, an alternative sigma factor from Neisseria gonorrhoeae, controls expression of msrAB, which encodes methionine sulfoxide reductase.

A DNA microarray was used to identify genes transcribed in Neisseria gonorrhoeae using Ecf, an alternative sigma factor. No differences between the transcriptional profiles of strain FA1090 and a mutant where ecf had been inactivated could be detected when both were grown in vitro. We therefore constructed a gonococcal strain in which Ecf can be overexpressed.

Comparative overview of the genomic and genetic differences between the pathogenic Neisseria strains and species.

The availability of complete genome sequences from multiple pathogenic Neisseria strains and species has enabled a comprehensive survey of the genomic and genetic differences occurring within these species. In this review, we describe the chromosomal rearrangements that have occurred, and the genomic islands and prophages that have been identified in the various genomes. We also describe instances where specific genes are present or absent, other instances where specific genes have been inactivated, and situations where there is variation in the version of a gene that is present.

The RpoH-mediated stress response in Neisseria gonorrhoeae is regulated at the level of activity.

The general stress response in Neisseria gonorrhoeae was investigated. Transcriptional analyses of the genes encoding the molecular chaperones DnaK, DnaJ, and GrpE suggested that they are transcribed from sigma32 (RpoH)-dependent promoters upon exposure to stress. This was confirmed by mutational analysis of the sigma32 promoter of dnaK.

Chloramphenicol-resistant Neisseria meningitidis containing catP isolated in Australia.

Earlier workers have described chloramphenicol resistance in meningococci isolated from cerebrospinal fluid sampled in patients in Vietnam (11 cases) and France (one case) during 1987-1996. Here we describe two distinct serogroup B strains isolated in Australia in 1994 and 1997, and found among approximately 1400 invasive meningococcal isolates examined in Australia over a 9 year period. Both were phenotypically chloramphenicol resistant on disc, Etest and agar inclusion MIC and acetylated chloramphenicol examination.