Healthcare Antiseptic Testing

Healthcare Antiseptics include antibacterial washes, hand sanitizers, surgical hand scrubs and pre-operative skin scrubs. Ideally these products provide broad spectrum, fast acting, and persistent antimicrobial protection to reduce pathogenic microorganisms on intact skin. Healthcare antiseptics have very different use profiles than consumer antiseptics that are used in homes and public places. They are used by healthcare workers in a wide variety of medical settings (i.e. hospitals, clinics, doctors’ offices, and nursing homes) to protect patients and visitors as well as to protect the individual user from the wide variety of harmful microorganisms which may be present in healthcare facilities. While the need to use antiseptics for consumer hand wash applications is debatable, healthcare antiseptics, especially in hospital settings, are critical components for preventing the spread of pathogenic microorganisms and to reducing hospital acquired infections that can result in longer or additional hospital stays/treatment, negative clinical outcomes, and increased costs.

Antimicrobial Wash Products include antibacterial hand washes, hand soaps, and body washes that are designed for frequent use to reduce the number of transient microorganisms. These antiseptic products are used with water and are washed off. Hands are dried following use. Protocols based on ASTM Standards such as E1174, E1327, and E1874 may be used to test the effectiveness of these antiseptic handwashing products using Serratia marcescens, Escherichia coli and Bacillus subtilis.

Antimicrobial Rub Products, like the alcohol-based hand rubs and other leave-on formulations, are designed to be applied full strength, rubbed in until dry, and used without water rinsing. These products may be tested for efficacy using methods based on ASTM Test Method E2755. E2755 can be used to test any form of hand rubs (gels, rinses, sprays, foams, and wipes) as long as they are used according to label directions at typical use dosages. This test method uses either Serratia marcescens or Staphylococcus aureus as the test organism.

Surgical Hand Scrubs. Surgical hand scrubs are antiseptic soaps used by surgical team members to remove debris and transient pathogens from their hands, fingernails, and forearms, as well as to reduce the resident microbial count, and to prevent the rapid regrowth of microorganisms. These products are used with water and are rinsed off after use, following a very specific, timed procedure. Hands and arms are dried using a sterile towel in the operating room.1 Testing protocols based on ASTM E1115 or E1874 may be used to evaluate the antiseptic efficacy of surgical scrub products. ASTM E1115 uses a “glove juice” bacterial recovery method, which is very effective at removing resident microorganisms from hands, and compares the baseline bacterial CFU (colony forming units) per hand with the post-treatment values. The log10 reductions are reported.

Pre-Operative Skin Scrubs. These fast acting antiseptic products are used to significantly reduce pathogenic organisms on intact skin prior to operative and catheterization procedures as part of the effort to prevent surgical site infections (SSIs) which are a primary source of healthcare associated infections (HAIs). These products may be water or alcohol based and contain an antiseptic such as povidone-iodine or chlorhexidine gluconate (CHG). These products come in many forms (liquids, creams, swab sticks, sponges, pads, and other various applicators), and are used following carefully outlined procedures that differ depending on the specific surgical site and other variables.2 Pre-operative scrubs may be tested using protocols based on ASTM E1173. Multiple microbial samples are collected before and after the use of the scrub product from specific skin sites, typically the inguinal region, the abdomen, the subclavian region, or the median cubital region of the arm. The log10 reduction from the baseline bacterial population is reported.

Overview of Healthcare Antiseptic Test Methods

The FDA requires efficacy data for healthcare antiseptics. The FDA is currently reviewing healthcare antiseptics, and has proposed a ruling that amends the 1994 Tentative Final Monograph (TFM) 3. In this proposed ruling4, they suggest that all healthcare antiseptic active agents should have in vitro studies to determine the agents' antimicrobial efficacy as well as in vivo clinical simulation studies showing specific log10 reductions are obtained and to demonstrate that the products are generally regarded as effective (GRAE). They also suggest changes regarding vehicle controls, active controls, sample size and neutralizers. The following table summarizes the differences between the current TFM and the proposed ruling for Clinical Testing, and indicates that the bar for bacterial log reduction may be raised in the near future.

Comparison of Clinical Simulation Testing Bacterial Log Reduction Effectiveness Criteria for the 1994 TFM and the Proposed Ruling4

(Table 8 from Proposed Rule)

Indication

1994 TFM

This proposed rule

Health care personnel hand wash or health care personnel hand rub

  • Reduction of 2 log10 on each hand within 5 minutes after the first wash, and

  • Reduction of 3 log10 on each hand within 5 minutes after the tenth wash

  • Reduction of 2.5 log10 on each hand within 5 minutes after a single wash or rub.

Surgical hand scrub or surgical hand rub

  • Reduction of 1 log10 on each hand within 1 minute after the first wash on day 1, and

  • Does not exceed baseline at 6 hours on day 1, and

  • Reduction of 2 log10 on each hand within 1 minute after the last wash on day 2, and

  • Reduction of 3 log10 on each hand within 1 minute after the last wash on day 5

  • Reduction of 2 log10 on each hand within 1 minute after a single wash or rub, and• does not exceed baseline at 6 hours.

Patient preoperative skin preparation

  • Reduction of 2 log10 per square centimeter on abdominal site within 10 minutes after use, and

  • Reduction of 3 log10 per square centimeter on groin site within 10 minutes after use, and

  • Does not exceed baseline at 6 hours

  • Reduction of 2 log10 per square centimeter on abdominal site within 30 seconds after use, and

  • Reduction of 3 log10 per square centimeter on groin site within 30 seconds after use, and

  • Does not exceed baseline at 6 hours.

strenGths of Healthcare Antiseptic Testing

A primary strength of antiseptic testing is that there are a variety of methods to choose from in order to insure that reliable, reproducible test results are obtained for the specific product type. Unique methods have been outlined for Hand Wash (E1174, E1327) and Hand Rub (E2755) testing. These Hand Wash and Hand Rub tests are quite different than the tests for evaluating the efficacy of Surgical Hand Scrubs and Pre-Operative Scrubs.

The methods for Hand Washes and Hand Scrubs are similar in that they both involve measuring a baseline number of organisms after artificially contaminating hands with the specific test organisms. Then, after appropriate washing or rubbing protocols have been completed, the number of organisms remaining on the hands are determined. The protocols vary, however, in order to take into account the different use practices for the products.

The Surgical Hand Scrub and Pre-operative Skin Scrub evaluations are similar in that they start with a baseline of resident microorganisms, they do not require application of additional microorganisms to the skin, and they both test for a reduction in overall CFUs. However, they are quite different in their skin preparation and microbial sampling due to the emphasis on hands for the Surgical Scrubs and other body parts for the Pre-operative Skin Scrubs.

While most of these methods involve requiring the volunteer subjects to refrain from using antimicrobial formulations for specified number of days prior to testing, ASTM E1327 does not.

Vivo Clinical Testing will work with you to understand your product application and limitations and will help you choose the best test methods to meet your needs.

weaknesses of Testing

These tests require human volunteer subjects with healthy skin. Some of the tests require up to a two week preparatory period and/or need volunteers with sufficiently high normal resident bacterial counts on the skin sites to be tested. As with any test method that simulates actual use, it is challenging to take all “real life” factors into account, and the test results will have limitations due to the assumptions used for the testing protocol. Vivo Clinical works with study sponsors to identify appropriate procedures and test conditions for testing protocols in order to best replicate use during actual patient procedures.

why vIVO cLINICAL tESTING?

Vivo Clinical Testing is a contract testing laboratory designed to support the hand hygiene and infection control industry. Vivo Clinical Testing was founded in 2017 by Dr. Benjamin Tanner, a respected microbiologist and owner of Microchem LaboratoryThe Vivo Clinical Testing laboratory offers testing in compliance with current FDA, Good Laboratory Practice (GLP), and Good Clinical Practice (GCP) regulations.  Clients are welcome to tour the lab, observe studies, and audit the lab's quality system. The lab is staffed by a capable, friendly group of scientists, mostly microbiologists.  We understand what our clients need:  Fairly priced testing services, done accurately and reported quickly.

references:

  1. How To Perform Surgical Hand Scrubs D. Gardner, Ellen Anderson-Manz, Infection Control Today. http://www.infectioncontroltoday.com/articles/2001/05/how-to-perform-surgical-hand-scrubs.aspx

  2. Patient Skin Antisepsis/Prep, AORN website. https://www.aorn.org/guidelines/clinical-resources/clinical-faqs/patient-skin-antisepsis-prep

  3. Federal Register Notice: Tentative Final Monograph for OTC Healthcare Antiseptic Drug Products – June 17, 1994 http://www.fda.gov/ohrms/dockets/ac/05/briefing/2005-4184B1_01_16-FDA-TAB15.pdf

  4. Safety and Effectiveness of Health Care Antiseptics; Topical Antimicrobial Drug Products for Over-the-Counter Human Use; Proposed Amendment of the Tentative Final Monograph; Reopening of Administrative Record May 2015 https://www.regulations.gov/#!documentDetail;D=FDA-2015-N-0101-0001