Identification of pathogenic bacteria carried by Musca domestica (Diptera: Muscidae) in the region of Wadi Eldawaser Empty Quarter at Saudi Arabia

Samples of common house fly Musca domestica were collected from Wadi Eldawaser of Saudi Arabia at different urban and rural locations viz., Alkhamasin, Sulayel and Tathleth (January 2010 till January 2011). These were examined using kits and routine cultural methods for microbiological identifications to determine the pathogenic bacterial species carried externally and internally by the flies. A total of 360 flies were collected of which 227 (63.05%) were found to carry pathogenic bacteria. Overall, 53 bacterial pathogen species were identified. The most frequent pathogens were found to be the enteric human pathogens such as Escherichia coli (18.7%), Klebsiella pneumoniae (7.5%) and Proteus vulgaris (6.3%). The other pathogens were Shigella dysentery (5.9%), Bacillus subtilis (5.3%), Staphylococcus aureus (5.1%), Pseudomonas aeruginosa (3.5%) and Salmonella paratyphi (2.7%). The highly pathogenic ones isolated three times and detected by the polymerase chain reaction (PCR) were Mycobacterium tuberculosis (causative agent of tuberculosis) and Chlamidiae trachomatis (causative agent of trachoma). Most of the isolated bacterial species could be found in both cold and warm seasons. Both Streptomyces sp., which is a chitinase producing bacteria from Elsulayel area (as the first record) and Bacillus thuringiensis which is known to be an effective biocontrol agent against insects were isolated. The current study provides information on the pathogenic bacteria that may be transmitted to humans by this nuisance flies, which is a serious health threat causing epidemics.