Bacteria ingestion by blowfly larvae: an in vitro study.
BACKGROUND
Maggot debridement therapy is the medical use of live fly larvae for cleaning chronic and infected wounds, removing devitalized tissue and decreasing the risk of infection. Maggot-derived proteins are able to kill bacteria, and proteolytic enzymes are responsible for the liquefying of necrotic tissue.


OBJECTIVE
The aim of this study is to investigate bacterial ingestion by larvae roaming free on bacterial agar, compared to those larvae contained within vinyl bags.


METHODS
Free-roaming sterile larvae of Lucilla sericata and larvae contained in vinyl bags were fed on Escherichia coli producing green fluorescent protein (GFP). The time interval to the onset of fluorescent maggots was determined. At different time intervals, maggots were sacrificed, washed in sterile saline, sagittally cut in frozen sections and examined under a microscope with UV light.


RESULTS
After feeding on GFP-labelled E. coli, maggots roaming free on bacterial lawn agar demonstrated fluorescence after 3 min, maggots entrapped in vinyl bags after 25 min. In the sagittal frozen sections, the highest fluorescent intensity was detected in the larvae's rostral part of the alimentary tract, the crop and the anterior midgut.


CONCLUSIONS
In an in vitro setting, digestion and ingestion of whole or disintegrated bacteria is accomplished within minutes. The vinyl bag's permeable membrane clearly causes a delay of this process.
Lerch
Klaus
K
Institute of Microbiology, University of Regensburg, Regensburg, Germany. klaus.lerch@klinik.uni-regensburg.de
Linde
Hans-Jörg
HJ
Lehn
Norbert
N
Grifka
Joachim
J
D000818:Animals; D004063:Digestion / Q000502:physiology; D004435:Eating / Q000502:physiology; D004926:Escherichia coli; D066298:In Vitro Techniques; D007814:Larva / Q000502:physiology*; D008567:Membranes, Artificial
D008567:Membranes, Artificial