The Australian Bush Fly (Musca vetustissima) as a potential vector in the transmission of foodborne pathogens at outdoor eateries

Abstract Australian outdoor activities are often accompanied by a barbeque (BBQ) with family, friends, and guests, which are often interrupted by uninvited guests in the form of the Australian bush fly, Musca vetustissima. We investigated the bacterial loading associated with the Australian bush in three different environments: on a cattle farm, in a typical urban area (shopping center car park), and at a BBQ. The highest bacterial populations per fly were found to occur in a farm environment (9.1×104 CFU per fly), whereas the bacterial population was lowest on flies caught in an urban environment (1.9×104 CFU per fly). The median CFU per fly caught near a BBQ was 5.0×104. Escherichia coli was the most commonly isolated potential pathogen, whereas Shigella sp. was the least common bacterial isolate that was screened. All isolated foodborne pathogens or indicator bacteria were screened for antibiotic resistance against commonly prescribed antibiotics. This revealed a very high prevalence of multidrug resistance, especially among the Salmonella and Shigella isolates of 94% and 87% resistance, respectively, against amoxicillin, roxythromycin and cefaclor.