Topical Treatment Options

A variety of bacterial pathogens and types of skin infections necessitate multiple therapeutic options. Topical antibacterial agents are extremely important and highly versatile in antimicrobial therapy. They are used to treat multiple skin infections, traumatic and surgical wounds, and are even used as prophylaxis to prevent infection. The following is an overview of topical antibacterial agents for uncomplicated skin infections:

Antiseptics

Agent	Mechanism of Action	Notes
Hydrogen peroxide	Damages bacterial DNA from highly reactive hydroxyl radicals	Used on intact skin and minor wounds Limited bactericidal activity May be detrimental to wound healing
Chlorhexidine	Disrupts cytoplasmic membranes	Often used as surgical hand scrubs, hand washes, superficial wound cleansers and preoperative skin preparation Remains active for hours after application Consistently superior to povidone-iodine and other antiseptics in reducing colonizing flora immediately and several days after application
Triclosan	Bacterial membrane disruption through blockade of lipid synthesis	Used in consumer products, such as soaps, detergents, toothpastes and cutting boards Resistance found in Escherichia coli strains
Iodophors	Destroys microbial protein and DNA	Requires 2 minutes of contact for full efficacy Commonly used for preoperative skin preparation Povidone-iodine is effective against MRSA and Enterococcus species Adverse reaction to povidone-iodine is low Prolonged use of povidone-iodine may cause contact dermatitis or metabolic acidosis Iodine/povidone-iodine is considered cytotoxic and deleterious to wound healing
Benzoyl peroxide	Broad-spectrum bactericidal	Most commonly used to treat acne vulgaris Effective against a wide range of organisms, including Staphylococcus captitis, Staphylococcus epidermidis, Propionibacterium avidum, Propionibacterium granulosum, Pityrosporum ovale and Propionibacterium acnes May be combined with clindamycin and erythromycin to increase efficacy

Antibiotics

Agent	Mechanism of Action	Notes
Mupirocin	Reversible inhibition of bacterial isoleucyl-tRNA synthetase prevents protein and cell wall synthesis.	Used to treat primary skin infections (eg, impetigo) as well as secondarily infected traumatic lesions Highly effective against gram-positive bacilli, such as Staphylococcus aureus Used as a prophylaxis against nasal carriage of S aureus Not effective against enterococci Rare, resistant strains of mupirocin-resistant MRSA have emerged despite unique mechanism of action
Neomycin	Bactericidal; Inhibits protein synthesis by binding the 30s subunit of bacterial ribosome.	Effective against most gram-negative bacilli, except Pseudomonas aeruginosa Effective against staphylococci but not streptococci or other gram-negative bacteria Resistance has been reported in staphylococci, E coli, Klebsiella and Proteus Can be systemically absorbed and cause systemic toxicity (eg, ototoxicity or nephrotoxicity) if applied to large areas
Polymyxin	Cationic decapeptide; surfactant that disrupts bacterial membranes	Effective against P aeruginosa, E coli, Enterobacter spp, Klebsiella spp Ineffective against Proteus, Serratia and gram-positive bacteria Very infrequently cause allergic contact dermatitis Frequently used with bacitracin, zinc and neomycin in a petroleum base
Bacitracin	Polypeptide; blocks bacterial cell wall formation	Primarily effective against gram-positive bacteria (streptococci, staphylococci, clostridia, and corynebacteria) Used to treat local infection Low cost, low toxicity May cause allergic contact dermatitis

Watch a video to see how bacterial skin infections develop.