Maggot-associated Ignatzschineria larvae bacteremia: a case report.

Background: Myiases are fly larvae parasitic infections involving host tissues. In humans, myiases generally occur in people with reduced self-care capacity or living in poor hygienic conditions, with wounds serving as an entry point for flies. In addition to direct larvae damage, myiases constitute a risk factor for secondary bacterial infections. Case summary: An 81-year-old patient with multiple comorbidities and living in poor hygienic conditions accessed the emergency room of a secondary care hospital in the Varese area following deterioration in his clinical condition and presence of maggots on his right leg. Blood cultures grew gram-negative bacilli, which could not be identified using standard procedures: biochemical tests yielded Pasteurella canis as a result with 95% probability, whereas matrix-assisted laser desorption ionization time-of-flight mass spectrometry could not find the spectrum in its database. The species Ignatzschineria larvae was determined by 16S rRNA sequencing, and its significance was interpreted upon consultation between microbiologists and clinicians. Conclusion: This case underscores the role of collaboration between clinical microbiology laboratories and clinicians in diagnosing and managing uncommon infections. The identification of I. larvae was obtained through 16S rRNA sequencing, highlighting how sequencing-based approaches are becoming increasingly implemented as diagnostic tools when traditional methods fail in identifying rare microorganisms.