Do maggots have an influence on bacterial growth? A study on the susceptibility of strains of six different bacterial species to maggots of Lucilia sericata and their excretions/secretions.

PURPOSE: The maggots of Lucilia sericata are successfully used as a treatment for infected wounds. Many articles are published about possible direct antibacterial properties of maggots and their excretions/secretions (ES), but with different results. The present study reinvestigates the susceptibility of six bacterial strains to maggots and their ES. METHODS: Live maggots were added to a bacterial suspension. After incubation for 16 h, the bacterial growth in this suspension was compared with the growth in a suspension without maggots. We tested Instar-1 and Instar-3 maggots and compared nutrient broths. A turbidimetric assay investigated the antibacterial activity of ES. Finally, we compared the bacterial growth of Gram-positive and Gram-negative bacteria. RESULTS: The test with live maggots showed an increase of bacterial growth. Instar-1 maggots stimulated more bacterial growth than Instar-3 maggots, as well as the use of a more nutritious broth. The turbidimetric assay showed no inhibition of bacterial growth. For all bacteria, except Pseudomonas aeruginosa, an increase in bacterial growth was shown. CONCLUSION: There is no direct antibacterial effect of maggots and/or ES in vitro, however in clinical observations maggot therapy is successful. More research is needed to focus on possible indirect antibacterial activity, such as an immune-related effect.

[Maggot therapy for treatment of severe infections in trauma surgery: "back to the future!"]. / Maden: Ein neues Konzept in der Behandlung von Infektionen in der Traumatologie -- "Back to the Future!"

The ancient method of larval therapy for treatment of acute and chronic infections has become a revival and a new dimension with introduction of the Biobag (Vitapad). With use of this therapy trauma patients suffering infectious complications can be treated very effective, which can reduce the overall time needed for treatment and can result in diminished invalidity.

The antimicrobial activity of maggots: in-vivo results.

In the literature maggot therapy is discussed as a promising and potent form of debridement therapy. The number of maggots needed to debride a wound is estimated at 10 per cm2, and more in case of a higher percentage of necrosis or slough. In the authors' hospital, from March 1999 to May 2002, 16 patients were successfully treated with maggot therapy. The average maggot treatment time was 27 days, with an average of seven maggot changes. Most patients were treated for osteomyelitis, with trauma being the leading aetiological factor. In accordance with in-vitro findings, maggot therapy was found to be more effective in gram-positive infected wounds. Gram-negative bacteria are cultured more often after maggot treatment than before it (p=0.001). The opposite effect was found for gram-positive infected wounds (non-significant p=0.07). In vivo maggots seem to be less effective against gram-negative infected wounds. The authors believe that a higher number of maggots is needed not only for a larger wound or a wound with a higher percentage covered with slough, but also for a wound infected with gram-negative bacteria.