Impetigo is a superficial, cutaneous infection caused by Staphylococcus aureus and Streptococcus pyogenes that primarily affects young children [1]. The non-bullous form is the most common (70% of cases), and is characterised by erythematous maculopapules that progress to vesicles filled with pus before rupturing, drying out and leaving a brown-yellow crust [1]. Non-bullous impetigo is most commonly secondary to other injury such as trauma or insect bites, but can also be a primary disease when caused by frank bacterial invasion of healthy, intact skin. Bullous impetigo is characterised by large vesicles (bullae) that burst leaving a characteristic brown-yellow crust or scab. Both S. aureus and S. pyogenes are implicated in non-bullous impetigo, whereas only S. aureus is responsible for bullous impetigo [1,2]. In tropical Australia, S. pyogenes may be the more common pathogen implicated in impetigo [3].

Without treatment, impetigo may progress to potentially serious immune sequelae such as post-streptococcal glomerulonephritis, or the superficial infection can invade into deeper tissues and cause cellulitis and sepsis [4,5]. Due to the risk of serious complications, as well as for public health and infection control reasons, antibiotic therapy to treat the disease is common [6,7]. Current therapeutic guidelines in several countries recommend topical therapy as first line treatment for localised impetigo, with recommended topical agents including fusidic acid, retapamulin, hydrogen peroxide and mupirocin [6]. Although these topical agents are generally regarded as safe, with few side-effects, they may not be suitable for all patients and for some, antibiotic resistance is an issue. Honey may represent an alternative to topically applied antibiotics [8] due to their innate antibacterial properties [9]. Current evidence suggests that the antibacterial activity of honey is due to a combination of osmotic activity, pH shock, hydrogen peroxide, and non-peroxide factors [9]. Non-peroxide factors include small molecules such as phenolics, flavonoids and antibacterial peptides that may not be present in all honeys. A well-known example is methylglyoxal (MGO), which is commonly found in manuka honey, a monofloral honey derived from Leptospermum species [10,11].

Honey products are already in current clinical use for the antibacterial treatment or infection prophylaxis of superficial burns, lacerations and ulcers [12,13]. Additionally, honey is currently being investigated as a treatment/prophylaxis for deeper wounds at risk of bacterial infection, including necrotising fasciitis (NCT04831112), diabetes-related wounds (NCT04849143) and pilonidal cyst wound-beds (NCT02485860). Given the potential for honey to be used for skin and wound infections, and the ongoing, significant threat of antibiotic resistance, we aimed to evaluate the in vitro antimicrobial activity of several types of honey against impetigo-causing bacterial isolates, with a view to determining whether honey is suitable as a clinical intervention for impetigo and as a potential alternative to antibiotics.