Browsing by Author "Shah, Chirag B."

Now showing 1 - 2 of 2

Antimicrobial activity of a novel catheter lock solution
(2002-06) Shah, Chirag B.; Mittelman, M. W.; Costerton, J. William; Parenteau, Stephen; Pelak, Michael; Arsenault, Richard; Mermel, Leonard A.
Intravascular catheter-associated bloodstream infections significantly increase rates of morbidity and hospital costs. Microbial colonization and development of biofilms, which are known to be recalcitrant to antibiotic therapy, often lead to the loss of otherwise patent vascular access systems. We evaluated a new taurolidine- and citrate-based catheter lock solution (Neutrolin; Biolink Corporation, Norwell, Mass.) for its activity against planktonic microbes, antimicrobial activity in a catheter model, and biofilm eradication activity. In studies of planktonic microbes, after 24 h of contact, 675 mg of taurolidine-citrate solution per liter caused >99% reductions in the initial counts of Staphylococcus aureus, Staphylococcus epidermidis, Pseudomonas aeruginosa, and Entercoccus faecalis. A solution of 13,500 mg/liter was cidal for Candida albicans. Ports and attached catheters inoculated with 50 to 600 CFU of these bloodstream isolates per ml were locked with heparin or the taurolidine-citrate solution. After 72 h, there was no growth in the taurolidine-citrate-treated devices but the heparin-treated devices exhibited growth in the range of 6 x 102 to 5 x 106 CFU/ml. Biofilms were developed on silicone disks in modified Robbins devices with broth containing 6% serum (initial counts, 106 to 108 CFU/cm2). The axenic biofilms were treated for 24 h with taurolidine-citrate or heparin. Taurolidine-citrate exposure resulted in a median reduction of 4.8 logs, whereas heparin treatment resulted in a median reduction of 1.7 logs (P < 0.01). No significant differences in the effects of the two treatments against P. aeruginosa and C. albicans were observed. These findings suggest that aurolidine-citrate is a promising combination agent for the prevention and treatment of intravascular catheter-related infections.
Efficacy of polyhexamethylene biguanide-containing antimicrobial foam dressing against MRSA relative to standard foam dressing
(2009-09) Kirker, Kelly R.; Fisher, Steve T.; James, Garth A.; McGhee, D.; Shah, Chirag B.
Many modern foam wound dressings possess a variety of attributes that are designed to create a supportive wound-healing environment. These attributes include absorbing exudate, providing optimum moisture balance at the wound surface, and preventing maceration of surrounding tissue. However, studies suggest that controlling wound bioburden should also be targeted when developing wound therapeutics. Thus, traditional foam dressings may absorb a copious amount of fluid, but may also provide an environment where microbes can grow unchallenged, leading to an increase in wound bioburden. However, antimicrobial foam dressings may prevent or reduce microbial growth, increasing the potential for wound healing. Studies reported herein evaluated the efficacy of 0.5% polyhexamethylene biguanide (PHMB) treated dressings to prevent the growth of methicillin- resistant Staphylococcus aureus (MRSA). An antimicrobial foam (Kendallâ„¢ AMD, Covidien, Mansfield, MA), which contains PHMB and a standard foam dressing (Copaâ„¢, Covidien, Mansfield, MA), which contains no PHMB (control), were directly inoculated with clinical isolate of MRSA and placed on a growth medium for selected time intervals. The presence or absence of microbial growth was quantified using plate counts and was visually assessed using scanning electron microscopy. At all time points, the antimicrobial foam dressing significantly reduced the MRSA growth compared to the control dressing. Similar results were also obtained in the microscopic evaluations.