Flies are important vectors of antimicrobial resistance (AMR) in food production, but their role in meat processing environments remains poorly characterized. This study isolated Enterobacteriaceae and Staphylococcaceae (including Mammaliicoccus sciuri ) from flies collected in bovine and swine slaughterhouses and meat processing industries. Phenotypic AMR was assessed, and the presence of selected antimicrobial resistance and virulence genes ( mecA , sea , see , sec , stx1 , stx2 , and eae ) was verified. Out of 60 flies collected, a total of 34 isolates were identified using MALDI-TOF with 13 different bacterial species, including Escherichia coli , Citrobacter braakii , C. freundii , Klebsiella pneumoniae , Hafnia alvei , Enterobacter kobei , S. aureus , S. epidermidis , S. saprophyticus , S. simulans , S. warneri , S. xylosus , and M. sciuri . Among Staphylococcaceae isolates, 17.6% were resistant to oxacillin and 23.5% to gentamicin. Regarding the Enterobacteriaceae isolates, 41.2% were resistant to streptomycin. Ten isolates (two E. coli , one S . epidermidis , two S. saprophyticus , one S. simulans , one S . warneri and three M. sciuri ) were considered multidrug-resistant (MDR). Notably, none of the targeted genes ( mecA , sea , see , sec , stx1 , stx2 , eae ) were detected by PCR. These findings suggest that flies can disseminate important resistant opportunistic bacteria in meat processing environments, posing concerns due to the capacity of flies to transmit these bacteria across food, processing facilities, animals and humans. These results underscore the need for continuous AMR surveillance and effective vector control to reduce the risks posed by flies in meat processing environments.

Foods can be contaminated by a wide range of microorganisms, originating from multiple sources within domestic kitchens. However, the role of flies and ants as carriers of bacteria in these environments remains poorly understood, and data on the antimicrobial susceptibility profiles of insect-associated bacteria remain scarce. Therefore, this study aimed to identify Enterobacterales and Staphylococcus spp. recovered from flies and ants collected in domestic kitchens and to characterize the antimicrobial susceptibility profiles of the isolates. Additionally, selected virulence genes were investigated in Staphylococcus aureus and Escherichia coli, two recognized foodborne pathogens. A total of 240 insects (113 flies and 127 ants) were collected from 58 domestic kitchens. Twenty-six Enterobacterales isolates belonging to nine species were recovered from 17 kitchens, including a single multidrug-resistant (MDR) isolate identified as Enterobacter hormaechei. In addition, 45 staphylococcal isolates representing nine species were recovered from 25 kitchens, originating from 36 flies and 9 ants. Among these, 13 isolates exhibited an MDR phenotype, including S. aureus and several non-aureus Staphylococcus species. None of the E. coli isolates carried the eae or stx1/stx2 genes, whereas none of the S. aureus isolates harbored the sea, seb, sec, see, or mecA genes. To the best of our knowledge, this is the first study to report the simultaneous recovery of MDR bacteria from flies and ants collected in domestic kitchens. These findings provide new evidence that household insects may act as carriers of antimicrobial-resistant bacteria, highlighting their potential role in the dissemination of clinically relevant bacterial species, including MDR strains, within domestic environments. Effective insect control and good household food hygiene practices may help reduce the spread of antimicrobial-resistant bacteria and mitigate the risk of difficult-to-treat foodborne infections.