CHG is a Potent Weapon Against HAIs

One of the weapons in an infection preventionist’s arsenal is chlorhexidine gluconate (CHG), an antimicrobial agent used as a surgical scrub, hand antiseptic and dental rinse, depending upon the percentage used in the formulation. CHG is becoming ubiquitious in the marketplace because of its efficacy against Gram-positive and Gram-negative organisms, aerobes, anaerobes and yeast.

CHG-based products play an important role in the prevention of hospital-acquired infections (HAIs) in several ways.

First, this antimicrobial agent can help prevent surgical site infections (SSIs), one of the most common HAIs responsible for at least 3.7 million additional days of hospitalization and a cost of at least $1.6 billion in hospital charges annually in the United States.

Among the preoperative steps recommended in the Guideline for Prevention of Surgical Site Infection (1999) from the Centers for Disease Prevention and Control (CDC) is the preoperative shower (although it has not been definitively shown to prevent SSIs) and preoperative surgical skin prep and surgical scrub using an FDA-approved antiseptic specifically designed for these purposes. The SSI guidelines cites a study of 700-plus patients who received two preoperative antiseptic showers; chlorhexidine gluconate was shown to reduce bacterial colony counts ninefold (2.83102 to 0.3), while povidone iodine or triclocarban-medicated soap reduced colony counts by 1.3- and 1.9-fold, respectively. While a number of broad-spectra antiseptic agents are available for preoperative preparation of patients’ skin at the incision site (including iodophors, alcohol-containing products and CHG), the SSI guideline notes, “In some comparisons of the two antiseptics when used as preoperative hand scrubs, chlorhexidine gluconate achieved greater reductions in skin microflora than did povidone iodine and also had greater residual activity after a single application. Further, chlorhexidine gluconate is not inactivated by blood or serum proteins.”

For the surgical scrub by operating room personnel, the SSI guidelines mandates that the product have a broad spectrum of activity, be fast-acting and have a persistent effect. Among the common antiseptic agents available for this purpose are alcohol, chlorhexidine, iodine/iodophors, parachlorometa-xylenol and triclosan, the SSI guidelines notes, “Povidone iodine and chlorhexidine gluconate are the current agents of choice for most U.S. surgical team members.”

Studies have indicated that a product containing a combination of 2 percent CHG and 70 percent isopropyl alcohol (IPA), or a product containing 4 percent CHG are effective bactericidal skin cleansers and can help improve clinical patient outcomes by reducing the skin-dwelling microorganisms that can trigger infections. Bacteria can adhere to and form biofilms on medical devices such as catheters, so the application of effective skin antisepsis is essential to reduce the incidence of catheter-related sepsis.

Adams, et al. (2005) sought to determine the antimicrobial efficacy of a 2 percent CHG and 70 percent IPA formulation and compare it with five other disinfectants using quantitative in vitro time-kill tests against Staphylococcus epidermidis RP62A at 30 seconds. The researchers found that in the suspension tests, four of the disinfectants achieved a log10 reduction factor greater than 5 at 30 seconds. However, data from the biofilm tests point to the efficacy of the 2 percent CHG and 70 percent IPA formulation and 10 percent aqueous PVI — both achieving a log10 reduction factor between 4 and 5 (P=0.28). Berenholtz, et al. (2004) also emphasized that using CHG for patient preoperative skin preparation, as well as adhering to evidence-based guidelines, can prevent CRBSIs, a cause of morbidity and mortality in critically ill patients.

Bleasdale, et al. (2007) report that the daily cleansing of patients in ICUs has been shown to help decrease CRBSIs. The study design was a 52-week, two-arm, crossover (i.e., concurrent control group) clinical trial with intention-to-treat analysis. The study setting was the 22-bed medical intensive care unit (MICU), which comprises two geographically separate, similar 11-bed units, of a 464-bed public teaching hospital. The study population comprised 836 MICU patients. During the first of two study periods (28 weeks), one hospital unit was randomly selected to serve as the intervention unit in which patients were bathed daily with 2 percent CHG-impregnated washcloths; patients in the concurrent control unit were bathed daily with soap and water. After a two-week wash-out period at the end of the first period, cleansing methods were crossed over for 24 more weeks. Main outcome measures included incidences of primary BSIs and clinical (culture-negative) sepsis (primary outcomes) and incidences of other infections (secondary outcomes). The researchers found that patients in the CHG intervention arm were significantly less likely to acquire a primary BSI (4.1 vs 10.4 infections per 1,000 patient days; incidence difference, 6.3 [95 percent confidence interval, 1.2-11.0). The incidences of other infections, including clinical sepsis, were similar between the units. Protection against primary BSI by CHG cleansing was apparent after five or more days in the MICU.

Second, this antimicrobial agent can facilitate skin antisepsis during catheter insertion and the application of dressings, as the density of skin flora at the catheter insertion site is a major risk factor for catheter-related bloodstream infections (CRBSIs). The CDC’s Guidelines for the Prevention of Intravascular Catheter-Related Infections (2002) states, “In the United States, povidone iodine has been the most widely used antiseptic for cleansing arterial catheter and CVC insertion sites. However, in one study, preparation of central venous and arterial sites with a 2 percent aqueous chlorhexidine gluconate lowered BSI rates compared with site preparation with 10 percent povidone iodine or 70 percent alcohol.” The guideline also cites a multi-center study in which a chlorhexidine-impregnated sponge placed over the site of short-term arterial and CVCs reduced the risk for catheter colonization and CRBSI, with no adverse systemic effects resulting from use of this device. A randomized controlled trial reported in the March 25, 2009 issue of the Journal of the American Medical Association also showed that using a sponge containing CHG as part of the dressing for intravascular catheters reduces the risk for major catheter-related infections in critically ill patients in the intensive care unit.

Third, this antimicrobial agent can help achieve antisepsis by being incorporated into coatings applied to catheters or being impregnated into the medical device. Studies that have addressed coated or impregnated catheters using chlorhexidine/silver sulfadiazine indicate these devices can help reduce CRBSIs; several meta-analyses demonstrated that such catheters reduced the risk for CRBSI compared with standard non-coated or impregnated catheters. A catheter with a chlorhexidine coating on both the internal and external luminal surfaces has three times the amount of chlorhexidine and extended release of the surface bound antiseptics than that in earlier generations of catheters, and studies indicate that prolonged anti-infective activity provides improved efficacy in preventing infections.

References:

Adams D, Quayum M, Worthington T, Lambert P, Elliot T. Evaluation of a 2 percent chlorhexidine gluconate in 70 percent isopropyl alcohol skin disinfectant. J Hosp Infect. 2005;61:287-290.

Bleasdale SC, et al. Effectiveness of chlorhexidine bathing to reduce catheter-associated bloodstream infections in medical intensive care unit patients. Arch Intern Med. 2007;167(19):2073-2079.

Berenholtz SM, Pronovost PJ, Lipsett PA, et al. Eliminating catheter-related bloodstream infections in the intensive care unit. Crit Care Med. 2004;32:2014-2020.

Timsit JF, et al. Chlorhexidine-impregnated sponges and less frequent dressing changes for prevention of catheter-related infections in critically ill adults. JAMA. 2009;301(12):1231-1241.

O’Grady NP, et al. Guidelines for the Prevention of Intravascular Catheter-Related Infections (2002). Morbidity and Mortality Weekly Report. Aug. 9, 2002. Vol. 51, No. RR-10.