PresentationA homeless man was seen in the emergency department complaining of pain in his leg. Based on the physician exam, the wound on the leg appeared to be infected. Fly larvae, or maggots, were present in the wound on examination.
Lab TestingCulture swabs were obtained from the wound area and transported to the hospital bacteriology laboratory for aerobic culture. The local laboratory was able to recover a gram-negative rod but was unable to identify the bacteria. Thus the isolate was sent to a reference laboratory for identification. At the reference laboratory the isolate was sub-cultured to Sheep Blood, Chocolate, and MacConkey agar. Matrix Assisted Laser Desorption Ionization-Time of Flight (MALDI-TOF) of the gram-negative rod was negative. The reference laboratory ultimately used 16s pyrosequencing to identify the organism as Ignatzschineria species.
Cause of SymptomsThe patient’s leg was infected with Ignatzschineria species, which was identified by 16s pyrosequencing at the outside reference laboratory. Ignatzschineria is a gram-negative, oxidase positive, catalase positive, asaccharolytic organism. This bacterium is commonly associated with the flesh fly called Wohlfahrtia magnifica and was felt to be the causative agent of the infected wound in the patient. The patient was homeless, which is a risk factor for a condition called Myiasis. Myiasis is a parasitic infestation of a live animal by fly larvae, commonly referred to as maggots. Flies are commonly attracted to open wounds in which they land on the open skin and lay their larvae. Myiasis is also an affliction in rural tropical areas were the myiatic flies thrive and often may require surgical intervention to be removed. The condition can be devastating to livestock. There are 3 main fly vectors associated with animal and human myiasis. Clues in humans that myiasis may be present include homelessness and recent travel to an endemic area, typically tropical regions of the world. Presentation often includes one or more non-healing lesions on the skin which can itch. Movement under the skin can often be seen (which are the live larvae). A discharge from a central punctum (tiny hole), or a small, white structure protruding from the lesion can also often be seen.
TreatmentIgnatzschineria species is commonly susceptible to a wide range of antimicrobials.
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