Development of Daptomycin Susceptibility Breakpoints for Enterococcus faecium and Revision of the Breakpoints for Other Enterococcal Species by the Clinical and Laboratory Standards Institute.

Daptomycin is one of the few treatment options for infections caused by enterococci that are resistant to ampicillin and vancomycin, such as vancomycin-resistant Enterococcus faecium. The emergence and clinical significance of daptomycin-resistant enterococci and evolving microbiologic, pharmacokinetic-pharmacodynamic, and clinical data indicated that the pre-2019 Clinical and Laboratory Standards Institute (CLSI) susceptible-only breakpoint of ≤4 μg/mL for daptomycin and enterococci was no longer appropriate. After analyzing data that are outlined in this article, the CLSI Subcommittee on Antimicrobial Susceptibility Testing established new breakpoints for daptomycin and enterococci.

Evaluation of Ciprofloxacin and Levofloxacin Disk Diffusion and Etest Using the 2019 CLSI Breakpoints.

In 2019, the Clinical and Laboratory Standards Institute (CLSI) published revisions to the ciprofloxacin and levofloxacin breakpoints. We evaluated the performance of disk diffusion and Etest compared to that of reference broth microdilution by use of the revised breakpoints. Fifty-eight isolates with ciprofloxacin MICs of 0.

Variability of Daptomycin MIC Values for Enterococcus faecium When Measured by Reference Broth Microdilution and Gradient Diffusion Tests.

Daptomycin has become a mainstay therapy for the treatment of serious vancomycin-resistant infections. However, concern exists that current testing methods do not accurately predict the clinical success of daptomycin therapy. We evaluated a collection of 40 isolates of across three centers by reference broth microdilution (BMD), and two gradient strips, to determine the precision of daptomycin MICs by these methods and the correlation of daptomycin MIC testing with mutations in the system, one of the primary daptomycin resistance mechanisms among the enterococci.

Alp, an arthropod-associated outer membrane protein of Borrelia species that cause relapsing fever.

Borrelia hermsii and other relapsing fever (RF) species are noted for their highly polymorphic surface antigens, the variable major proteins (VMP). Less is known about other surface proteins of these pathogens in either their vertebrate reservoirs or arthropod vectors. To further characterize these proteins, we elicited antibodies against VMP-less cells, noted antibody reactions against whole cells and cell components, and then subjected selected antigens to mass spectroscopy for amino acid sequencing for comparison against a B.

Tfap2 transcription factors in zebrafish neural crest development and ectodermal evolution.

Transcription factor AP2 (Tfap2) genes play essential roles in development of the epidermis and migratory cells of the neural crest (NC) in vertebrate embryos. These transcriptional activators are among the earliest genes expressed in the ectoderm and specify fates within the epidermis/crest through both direct and indirect mechanisms. The Tfap2 family arose from a single ancestral gene in a chordate ancestor that underwent gene duplication to give up to five family members in living vertebrates.