A Plasmid Confers Hypermucoviscosity-Like Phenotype and Alters Capsule Production and Virulence.

Hypermucoviscosity (hmv) is a capsule-associated phenotype usually linked with hypervirulent strains. The key components of this phenotype are the RmpADC proteins contained in non-transmissible plasmids identified and studied in . is closely related to and recently has been identified as an emergent human pathogen.

Antibiotic resistance of gram-negative bacilli isolated from pediatric patients with nosocomial bloodstream infections in a Mexican tertiary care hospital.

Background: Gram-negative bacilli are the most common bacteria causing nosocomial bloodstream infections (NBSIs) in Latin American countries.

Methods: The antibiotic resistance profiles of Gram-negative bacilli isolated from blood cultures in pediatric patients with NBSIs over a 3-year period in a tertiary care pediatric hospital in Mexico City were determined using the VITEK-2 system. Sixteen antibiotics were tested to ascertain the resistance rate and the minimum inhibitory concentration using the Clinical Laboratory Standards Institute (CLSI) broth micro-dilution method as a reference.

OmpR phosphorylation regulates ompS1 expression by differentially controlling the use of promoters.

The Salmonella enterica ompS1 gene encodes a quiescent porin that belongs to the OmpC/OmpF family. In the present work we analysed the regulatory effects of OmpR phosphorylation on ompS1 expression. We found that in vivo, OmpR in its phosphorylated form (OmpR-P) was important in the regulation of the two ompS1 promoters: OmpR-P activated the P1 promoter and repressed the P2 promoter in an EnvZ-dependent manner; expression occurs from the P2 promoter in an ompR mutant.