Carriage of Bacteria by Proboscises, Legs, and Feces of Two Species of Flies in Street Food Vending Sites in Ouagadougou, Burkina Faso

Abstract

Flies are widely recognized as potential reservoirs and vectors of bacteria. In the present study, an attempt was made to assess meat-poultry and local fruit juice processing and vending sites for their hygienic status and the presence of houseflies, Musca domestica, and blow flies, Lucilia caesar, for bacterial carriage. The hygienic status results revealed the presence of waste and sewage nearby which provided food and harborage for flies. On the two sites, the M. domestica population was dominant ranging from 76.48 to 91.30%, while the L. caesar population rate ranged from 8.70 to 23.52%. Using specific growth media for bacteria and biochemical tests, bacterial carriage of pooled fly proboscises, legs, and feces were assessed. For both flies, 66.67 to 100% of feces pools were positive for Shigella, Salmonella, and streptococci, while 35.41 to 82.05% of leg and proboscis pools were positive for the same bacteria. In assessment, 0 to 2.56% of feces pools and 8.33 to 28.20% of leg and proboscis pools were staphylococci positive. Coliforms were detected in 100% of pooled organs, while 10 × 103 to 1.1 × 103 CFU with predominance of coliforms, streptococci, and Shigella were counted on legs and feces of houseflies captured on the two vending sites. Blow flies from the same vending site had an organ bacterial load in the range of 3 × 102 to 2.7 × 103 CFU per organ. Coliforms, Shigella, and streptococci were present in high numbers. Staphylococci was noticed in low numbers in all parts tested of both flies. Captured housefly and blow fly bacteria-releasing frequency through feces was estimated at 5 to 35 CFU per feces sample for Salmonella and 85 to 495 CFU per feces sample for Shigella.