Antimicrobial Elastomerics In Medicine: Why Now, Where Needed, What Attributes for Success

Advances in medical technologies over the last several decades have been astounding.  We save the lives of severely premature babies routinely and of critically burned patients who previously would have had no chance of survival. Hearts, livers, lungs and bone marrow are transplanted almost routinely.   Mechanical devices are implanted to replace bones, enable the deaf to hear, bring relief to those with chronic pain, and provide a long term means of blood cleansing to those with failing kidneys.  Yet, at the same time, we have been unable to prevent, or even substantially reduce, the likelihood of acquiring an infection while under medical care.  Why? 

There are several reasons.  First, these specific medical advances, along with so many others, usually leave the patients more vulnerable to infection due to immature, impaired, suppressed or “distracted” immune responses.   Second, many pathogenic bacteria, viruses and fungi, have become increasingly resistant to the antibiotics and drugs normally used to treat them.  Third, many pathogenic microorganisms have become more virulent, while others have added new routes of entrance into the body.  Still others have jumped from using domestic or wild animals as hosts in which to live, to causing disease in humans.  Forth, no matter how hard we try, devices used to enter the body often introduce microorganisms.  Those devices that remain in the body are candidates for initiating biofilm formation.  Biofilms are amazing cooperative communities of communicating bacteria with specialized responsibilities thriving in a highly protective exopolymeric matrix.  Bacteria within the biofilm matrix are up to 2,400 times more resistant to antibiotics than the same organism outside the biofilm.  Fifth, we have become acutely aware that the environmental surfaces surrounding infected patients become significantly contaminated, and that many of these organisms remain viable for days to months.  Such contaminated surfaces serve as reservoirs for infection as pathogens can readily be transferred to hands, gloves, apparel and instruments to be transported to new patients or to secondary surfaces.

Antimicrobial medical devices and protective apparel will “kill” pathogens before they can cause an infection; as they try to attach to catheters and implants before they can initiate biofilm formation; as they land on environmental and instrument surfaces near a patient; or on contact as they are touched by treated gloves, masks or apparel.   Avoiding the infection removes the opportunity for the pathogen to develop resistance.

Antimicrobial selection needed will be determined by the type of surface to be treated, the tissues contacted, the environment to which the antimicrobial will be exposed and the pathogenic threats anticipated.  Most situations will require that the antimicrobial be biocidal rather than bacteriostatic, that it remain effective as a biocide in the presence of organic soiling (e.g. blood, tissues), that it remains active for the length of time the treated device or apparel is used, and that it does not harm the patient or healthcare provider.

This presentation will expand on the current threats and further define the characteristics necessary for success of antimicrobials on elastomeric materials for different devices and products.