The HPI Division needs your Science Art: This is a reminder for submitting one of your amazing research images to Helen Chomicki (helen.chomicki@vanderbilt.edu) by the end of this week. Submitted images will be printed and displayed as art on our corridor walls.
HPI Division Meeting: November 25 , 2014 at 3:00pm, MCN A5305 - Business meeting.
2nd Friday Happy Hour: 11/14/14 at MCN A5305, 4:00pm - Hosted by the Jonathan Irish and Peggy Kendall labs.
Publications: A total of 21 highly collaborative publications from HPI faculty have been posted on Pubmed in the month of October. The listings and links to all publications follow below.
New Resource: In case you missed this, VU has acquired a year-long subscription to PIVOT, which is a platform that provides registered users with access to funding opportunities, as welll as research profiles of all PIVOT members. Faculty, students and staff can create an account at https://pivot.cos.com/register. Pivot is also accessible from the Office of Sponsored Programs website. When accessing the site from a Vanderbilt domain, researchers will be able to create an account and claim their profile. Once created, an account is accessible through any computer, on or off campus.
"Inter- and intraspecies metabolite exchange promotes virulence of antibiotic-resistant Staphylococcus aureus."
Hammer ND & Cassat JE et al.,Cell Host Microbe 2014; 16(4):531-7
Bacterial behavior is constantly shaped in response to the selective pressures imposed on a bacterial population by changes in its micro-environment. Thus, while studies investigating bacterial mono-cultures can and oftentimes do provide substantial insights into key bacterial pathways, they are not always reflective of what really happens during infection in vivo.
In the case of S. aureus, a human pathogen that can successfully colonize and damage a wide variety of host niches, small colony variants are associated with chronic and persistent infections. These variants arise in vivo and have acquired genetic lesions that impair metabolic pathways, yet this fitness cost appears to be offset by an increased tolerance to antibiotic treatment.
Hammer, Cassat and colleagues demonstrated in this article that loss of nutritional fitness, associated with a gain in antibiotic resistance, can be overcome in vivo via a form of "inter-bacterial complementation", during which bacteria that lack the ability to metabolize or produce a specific nutrient can benefit by bacterial siblings that do not suffer the same mutation (see image below).
Hammer, Cassat et al. then demonstrated that slow-growing isolates of different bacterial species (including S. aureus small colony variants) from respiratory secretions of cystic fibrosis patients also exhibited accelerated growth when co-cultured. Taken together these observations highlight how bacterial communities diversify in vivo and can complicate treatment.
What are your thoughts? Feel free to muse by sending us an email (maria.hadjifrangiskou@vanderbilt.edu, helen.chomicki@vanderbilt.edu)
