Bacterial pathogens identified from houseflies in different human and animal settings: A systematic review and meta-analysis.

Housefly (Musca domestica) is an excellent candidate for the distribution of susceptible and resistant bacterial strains that potentially threaten public health. To date, there is a paucity of information on the global distribution of pathogenic bacteria of medical and veterinary importance from diverse environmental settings. Therefore, this study was undertaken to conduct a systemic review and meta-analysis to estimate occurrence of various bacterial species of medical and veterinary importance harboured by houseflies around the world. Published articles from 1980 to 2020 were retrieved from electronic databases and assessed for eligibility according to Preferred Reporting Items for Systemic Reviews and Meta-Analysis guidelines. Seventy-eight studies were included in the review with only 44 studies being eligible for meta-analysis. Results indicated that eligible studies used in this review were from four continents, i.e., Asia (47.4%) America (23.1%), Africa (20.5%) and Europe (8.9%). The majority of the studies (56.4%) used the culture method for the identification of bacterial pathogens, while 30.7% used both culture and PCR techniques. For meta-analysis, we focused on five pathogenic bacterial species including Escherichia coli, Enterococcus faecium, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. High heterogeneity was found among studies investigating different pathogens including E. coli (Q = 10,739.55; I  = 99.60; Q-p 0.0001), E. faecium (Q = 317.61; I  = 86.46; Q-p < 0.0001), K. pneumonia (Q = 1,576.61; I  = 97.27; Q-p < 0.0001), S. aureus (Q = 2,439.12; I  = 98.24; Q-p < 0.0001) and P. aeruginosa (Q = 1,283.0; I  = 96.65; Q-p < 0.0001). Furthermore, it was observed that houseflies carried a considerable number of susceptible and antibiotic-resistant bacterial strains that pose considerable threats to public health. Findings from this study have provided more insight on the vectoral potential of houseflies in the transmission of significant bacterial pathogens from different regions across the world. Further investigation is required to quantify the bacterial contamination and dissemination by houseflies.