Staphylococcus aureus, or staph, is a common bacterium found on human skin and in the nose, often without causing issues. If this microorganism enters the body through a break in the skin, it can lead to various infections. Chlorhexidine is an antiseptic widely used in healthcare settings. This article explores staph infections and how chlorhexidine combats these bacteria, including important considerations for safe application.
Understanding Staph Infections
Staphylococcus aureus is commonly found on the skin and in the nose of approximately 30% of individuals. While often harmless, it can cause infections if it penetrates the body, typically through cuts or other skin breaches. These infections range from mild skin conditions like pimples, boils, and impetigo, to more severe issues such as bloodstream infections, pneumonia, and bone infections. Staph infections can also manifest as endocarditis, an infection of the heart valves. Different types of Staphylococcus aureus exist, including Methicillin-sensitive Staphylococcus aureus (MSSA) and Methicillin-resistant Staphylococcus aureus (MRSA). MRSA has developed resistance to certain common antibiotics, posing a greater treatment challenge.
Chlorhexidine: What It Is
Chlorhexidine functions as both an antiseptic and a disinfectant. It exhibits broad-spectrum antimicrobial activity against a wide array of microorganisms, including Gram-positive and Gram-negative bacteria, fungi, and some viruses. This chemical is a cationic polybiguanide, typically used in salt forms like gluconate or acetate. Chlorhexidine’s mechanism involves its positively charged molecules binding to the negatively charged surfaces of bacterial cell walls. This electrostatic interaction disrupts the cell membrane, leading to the leakage of essential internal components. At lower concentrations, chlorhexidine inhibits bacterial growth (bacteriostatic effect). At higher concentrations, it causes the precipitation of cellular contents, resulting in bacterial cell death (bactericidal effect). In laboratory settings, chlorhexidine can eliminate nearly all Gram-positive and Gram-negative bacteria within 30 seconds.
Effectiveness Against Staph
Chlorhexidine is effective against various strains of Staphylococcus aureus, including both MSSA and antibiotic-resistant MRSA. Its antimicrobial action directly targets staph bacteria by disrupting their cell membranes, leading to the leakage of internal contents. The uptake of chlorhexidine by S. aureus occurs quickly, often within 20 seconds. Chlorhexidine possesses a sustained antimicrobial effect, maintaining activity for up to 12 hours on the skin. This prolonged action is due to its ability to bind to proteins in human tissues, providing continuous bacterial reduction. Studies demonstrate that routine chlorhexidine bathing can significantly reduce MRSA acquisition and carriage in healthcare environments, with one study reporting an 82% reduction in MRSA incidence. Chlorhexidine also shows effectiveness against Staphylococcus epidermidis in biofilms.
Using Chlorhexidine Safely
Chlorhexidine is widely used for practical applications such as skin preparation before surgery, routine hand hygiene, and patient bathing for decolonization purposes. For surgical procedures, a 2% chlorhexidine antiseptic is often recommended for use the night before and on the morning of surgery to reduce the bacterial population on the skin. In healthcare settings, daily bathing with chlorhexidine is a common practice for patients, particularly those in intensive care units, to help control the spread of MRSA and other microorganisms.
It is important to use chlorhexidine externally only. Contact with sensitive areas like the eyes, ears, nose, mouth, or other mucous membranes should be avoided. If chlorhexidine enters the ear canal with a ruptured eardrum, it can potentially lead to deafness. Ingesting chlorhexidine can cause stomach irritation.
Possible side effects include skin irritation, rashes, itching, or redness, and in rare instances, serious allergic reactions. Oral rinses containing chlorhexidine may lead to temporary changes in taste or tooth discoloration. Always adhere to product instructions and guidance from healthcare professionals for proper usage and concentration. For instance, when using chlorhexidine for bathing, certain soaps should be avoided below the jawline as they can inactivate the antiseptic.