January 29, 2013

Greg Anderson, a former post-doc and current Assistant Professor at IUPUI, is the lead author on a current paper from the lab published in Pathogens and Disease.  In this work, Greg used a bacterial-epithelial cell co-culture model to test the efficacy of fosfomycin/tobramycin antibiotic combination versus P. aeruginosa biofilms.  This study showed that the fosfomycin/tobramycin combination worked as well as tobramycin alone in reducing viable biofilm-grown P. aeruginosa, and when treating at sub-inhibitory levels, reducing inflammatory cytokine production, despite the fact that the fosfomycin/tobramycin combination had 4-fold less tobramycin that the tobramycin-only control.  Thus, this combination therapy works well and may reduce some of the potential side effects of aminoglycoside antibiotics.  This project was done in collaboration with and was supported by Gilead Sciences, which makes the fosfomycin/tobramycin combination therapy.

January 24, 2013

Mike Zegan's M.D., a long-time collaborator, had a recent study in JAMA cited in the Aspergillus News Letter.  You can download the paper at the link titled:  Mycotic Ulcer Treatment Trial: A Randomized Trial Comparing Natamycin vs Voriconazole.  In this report, an international team of scientists showed that, as stated on the website, "Natamycin treatment was associated with significantly better clinical and microbiological outcomes than voriconazole treatment for smear-positive filamentous fungal keratitis, with much of the difference attributable to improved results in Fusarium cases."  This work will likely impact the standard of care for these infections.

January 17, 2013

A recent article in Renal and Urology News highlighted a clinical study showing that sodium citrate works better than the commonly used heparin as a catheter lock solution in hemodialysis patients.  The study, published in the American Journal of Health-System Pharmacy by Yon and Low, both clinical nephrology pharmacists in the Veterans Affairs San Diego Healthcare System, was based in part on a series of studies led by Robert Shanks Ph.D., a post-doctoral fellow in my lab and in collaboration with Martha Graber M.D., a nephrologist at the Dartmouth-Hitchcock Medical Center.  Dr. Shanks is now an Associate Professor at the University of Pittsburgh.  Our studies compared the impact of various catheter lock solutions on biofilm formation by Staphylococcus aureus and S. epidermidis, two bacteria that commonly colonize and infect catheter lines.  In a paper we published in 2005, we showed that heparin actually stimulates biofilm formation by S. aureus on catheter-like material, and demonstrated the existence of a pathway in the organism that likely responds to the presence of heparin by enhancing the biofilms typically formed by these organisms.  A subsequent study in 2006 in Nephrology Dialysis Transplantation showed that sodium citrate at concentrations above 0.5% efficiently inhibits biofilm formation and cell growth of S. aureus and S. epidermidis, and for those organisms most typically associated with these infections, so-called coagulase negative Staphylococci, sub-inhibitory levels of citrate did not promote biofilm formation.  Together, these studies strongly suggested that a switch from heparin to sodium citrate might reduce infections in patients on dialysis.  The recent publication in American Journal of Health-System Pharmacy indeed confirmed this hypothesis in a study of 60 hemodialysis patients, which showed a reduction in infection from 33% in patients using heparin to 19% of patients using citrate as a catheter lock solution.  Thus, the studies in the lab have had a positive impact on reducing infections in patients.

January 15, 2013

Juliette Madan, a colleague and collaborator here at Dartmouth, was elected to the Society for Pediatric Research.  SPR is the major pediatric academic society for faculty engaged in a research career, and requires substantial evidence of successful contributions as well as ongoing promise in research.  This is an important milestones in an academic career, and is very well-deserved.  Congrats!