Characterization of Carbapenemase- and ESBL-Producing Gram-Negative Bacilli Isolated from Patients with Urinary Tract and Bloodstream Infections.

A total of 199 Gram-negative bacterial isolates from urinary tract infections and 162 from bloodstream infections were collected from 12 healthcare systems throughout the United States between May 2021 and August 2022. The isolates, phenotypically non-susceptible to 2nd or 3rd generation cephalosporins or carbapenems, were characterized through antimicrobial susceptibility testing and whole genome sequence analysis to obtain a broad snapshot of beta-lactamase-mediated resistance among these two sample types. Overall, 23 different carbapenemase genes were detected among 13 species (20.

Immune response to the Chlamydia trachomatis outer membrane protein PorB.

The antigenicity of the outer membrane protein PorB during exposure to Chlamydia trachomatis was evaluated in humans and its immunogenicity was tested in mice. Although natural human infection resulted in strong serological responses to the major outer membrane protein (OmpA), antibodies to PorB were low or absent. Analogous to the responses observed in humans, mice inoculated with EB or challenged with EB produced weak anti-PorB antibody responses.

Antigenic topology of chlamydial PorB protein and identification of targets for immune neutralization of infectivity.

The outer membrane protein PorB is a conserved chlamydial protein that functions as a porin and is capable of eliciting neutralizing Abs. A topological antigenic map was developed using overlapping synthetic peptides representing the Chlamydia trachomatis PorB sequence and polyclonal immune sera. To identify which antigenic determinants were surface accessible, monospecific antisera were raised to the PorB peptides and were used in dot-blot and ELISA-based absorption studies with viable chlamydial elementary bodies (EBs).