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Acquisition and retention of Clostridium difficile by Musca domestica larvae and pupae during metamorphosis
M P Davies1, M Anderson1, A C Hilton2
1Killgerm Chemicals Ltd, Ossett, UK.
Background:
Transfer of Clostridium difficile by Musca domestica has been demonstrated, revealing their potential for disseminating infection in the hospital environment.
Aim:
To determine the ability of M. domestica larvae to acquire and retain C. difficile throughout their metamorphosis into adult flies.
Methods:
Larvae were exposed to spores of C. difficile in a faecal emulsion, and examined externally and internally to determine carriage and internalization of spores through their development to adults.
Findings:
Larvae harboured C. difficile externally, with means of 21.56+/-5.76 colony-forming units (cfu) at Day 0, 22.44+/-9.90 cfu at Day 2, decreasing to 0.56+/-0.34 cfu at Day 4, with no C. difficile isolated thereafter. The same larvae harboured C. difficile internally, with means of 587.33+/-238.29 cfu at Day 0, decreasing to 297.44+/-155.21 cfu at Day 2, decreasing further to 73.67+/-46.74 cfu at Day 4, with no C. difficile isolated thereafter. The zero recovery of C. difficile coincided with the development of M. domestica larvae into pupae. From Day 6 onwards, all larvae had developed into the pupal stage and no C. difficile was recoverable from any pupae. No C. difficile was recovered from adult flies (emerged on Day 12) or empty puparia.
Conclusion:
Although C. difficile spores are readily acquired and internalized by larvae during feeding, they are not retained through development to adults. Adult flies therefore acquire C. difficile contamination as adults. The potential antimicrobial action of M. domestica larvae and their extracts against C. difficile spores warrants further investigation.
Insights
House flies (Musca domestica) larvae can acquire and internally harbor Clostridium difficile spores. However, the bacteria are not retained through metamorphosis into adult flies, suggesting adult flies acquire contamination separately.
Area of Science:
- Medical Entomology
- Infectious Diseases
- Microbiology
Background:
- Clostridium difficile (C. diff) transmission by house flies (Musca domestica) is a known concern for hospital-acquired infections.
- Understanding the role of the fly life cycle in C. diff dissemination is crucial for infection control.
Purpose of the Study:
- To investigate the capacity of Musca domestica larvae to acquire and retain Clostridium difficile spores during their development.
- To determine if C. difficile is carried through metamorphosis from larval to adult stages.
Main Methods:
- House fly larvae were exposed to C. difficile spores in a fecal emulsion.
- Larvae were monitored for external and internal C. diff carriage throughout development.
- Spore presence was quantified using colony-forming units (cfu) at various time points.
Main Results:
- C. difficile was detected both externally and internally in Musca domestica larvae.
- Internal spore counts decreased significantly from Day 0 to Day 4.
- No C. difficile was recovered from pupae or adult flies, coinciding with the completion of larval metamorphosis.
Conclusions:
- Musca domestica larvae can acquire and internalize C. difficile spores but do not retain them through metamorphosis.
- Adult flies likely acquire C. difficile contamination independently of larval stages.
- Further research into potential antimicrobial properties of fly larvae against C. difficile is warranted.
