Even products used to sterilize can contaminate

April 2008

Recent headlines regarding the possible microbial contamination of heparin vials gained international media attention.

Although the ultimate culprit was non-infectious in this case, it serves as a reminder of the consequences of such an event. There are numerous prior examples of pharmaceutical products that have been contaminated with bacterial or fungal pathogens causing disease. Although these cases gained widespread national media attention, there may be a medium lurking in the offices of each practicing physician that can also harbor infectious agents. The culprits in this case appear more benign since they are the very agents used to sterilize, namely, the antiseptics: alcohol, chlorhexidine, benzalkonium chloride, and povidine-iodine.

It seems counterintuitive that these agents marketed for their antimicrobial properties can themselves be subject to contamination, however there are several case reports in the literature where contaminated solutions ultimately caused disease. A sampling of these historical contaminations by agent is listed in the chart below:

There were multiple causes of contamination identified for each of these agents. In many cases, some point in the manufacturing process was violated and resulted in introduction of the pathogen. An example is that organisms can colonize water supplies. The organisms present there develop a biofilm on the water piping systems. Much in the same manner an infected catheter can shed this biofilm from time to time, organisms can enter final product and set up for contamination. The organism is not susceptible to the effects of the antiseptic solution due to the protective nature of this biofilm.

Contamination can also occur during terminal product use. Frequent clinical scenarios included use of a bulk bottle supply that becomes contaminated with repeated access. Given the frequency with which these solutions are used, many exposures can occur before the microbial pathogen is detected. Another source of entry for these organisms is the use of inappropriate diluent when preparing the final product to be used.

Not all of these cases of contamination can be predicted or prevented; however, they serve as an important reminder that even these antimicrobial solutions can serve as reservoirs for disease. Bulk containers of these products can provide convenience in many clinical settings; however, use should be limited to only cases where such high-volume use is warranted. Whenever possible, single-use applicators are preferred.

In a recent review by David J. Weber, MD, MPH, and colleagues from the University of North Carolina Health Care System, the following recommendations are proposed to help in avoiding contamination of these antiseptics and disinfectants:

• Use only CDC-recommended and FDA-cleared antiseptics.
• Use all germicides at their recommended use dilution and do not overdilute products.
• Use sterile water to dilute antiseptics.
• Use all germicides for the recommended contact times.
• Do not use germicides labeled only as antiseptics for the disinfection of medical devices or surface disinfection.
• Follow the recommended procedures in the preparation of products to prevent extrinsic contamination of products.
• lSmall-volume dispensers that are refilled from large-volume stock containers should be used until they are entirely empty and then should be rinsed with tap water and air dried before they are refilled.
• Store stock solutions of germicides as indicated on the product label.

So, when you begin your spring cleaning this year, remember to clean your cleaners too!

For more information:

• Elizabeth Dodds-Ashley, PharmD, MHS, is an Associate in Research/Clinical Pharmacist at the Duke University Medical Center Division of Infectious Diseases.
• Weber DJ, Rutala WA, Sickbert-Bennett EE. Outbreaks associated with contaminated antiseptics and disinfectants. Antimicrob Agents Chem. 2007;51:4217-4224.