Jornal de Doenças Infecciosas e Medicina Preventiva
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A Recent Evaluation of the Sandfly, Phlepotomus Papatasi Midgut Symbiotic Bacteria Effect on the Survivorship of Leshmania Major

Mostafa I Hassan, Bahera M AlSawaf, Mohamad A Fouda, Shaa

Like most entomophagus insects, the sandfly, Phlebotomus papatasi harbor both Gram-negative and Grampositive bacteria in her midgut. The biological interactions between these bacteria and Leishmania parasites they transmit are not fully understood. In an effort to declare these interactions, the present study has been carried out. A total of six bacterial species were identified from the midgut of the sandfly, Phlebotomus papatasi. These species were; Alcaligenes faecalis, Haemophillus parainfluenzae, Shigella sonnei, Serratia liquefaciens (Gram-negative bacteria); Listeria seeligeri and Bacillus thuringiensis (Gram-positive bacteria). The in vitro effect of each isolated midgut bacteria species on the survivorship of L. major (promastigotes) was investigated. Results indicated that the most effective bacterial species was B. thuringiensis followed by H. parainfluenzae (at all concentrations used), where they caused 100% mortality of Leishmania promastigotes. In addition, the present study dealt with the interactions between the midgut bacteria and Leishmania parasites in P. papatasi. The results indicated that the aposymbiotic sandflies (with midgut-free bacteria) were more susceptible to the infection with L. major (81.25 % vs. 23.3%) than symbiotic ones (with midgut bacteria). This result may indicate that midgut bacteria play a very important role in inhibiting the development of Leishmania parasites, thus preventing the sandfly, Phlepotomus paptasi from transmitting Leishmania major to her hosts.