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Bombyx mori as a model for Niallia circulans pathogenicity
M Ismail Hossain1, Nusrat U A Saleh1, Al Numan1
1Department of Biochemistry and Microbiology, School of Health and Life Sciences, North South University, Dhaka, Bangladesh.
Drug Discoveries & Therapeutics
|February 27, 2023
Summary
Niallia circulans, an opportunistic pathogen, kills Bombyx mori silkworm larvae. This study shows silkworms can model N. circulans infections and screen antibiotic effectiveness against this growing threat.
Area of Science:
- Microbiology
- Infectious Diseases
- Immunology
Background:
- Antibiotic resistance in pathogenic bacteria is a global health concern.
- Niallia circulans (formerly Bacillus circulans) is an opportunistic human pathogen with emerging antibiotic resistance.
- Invertebrates offer a cost-effective and ethically viable model for studying human bacterial infections.
Purpose of the Study:
- To investigate the pathogenicity of N. circulans in a Bombyx mori silkworm model.
- To assess the efficacy of various antibiotics against N. circulans infections in vivo.
- To evaluate the potential of B. mori larvae as a model for screening anti-N. circulans therapeutics.
Main Methods:
- Larval infection via hemolymph and midgut injection of N. circulans.
- Monitoring of larval mortality, melanization, and phenoloxidase (PO) activity.
- Quantification of bacterial load and hemocyte counts in hemolymph.
- Gene expression analysis (RT-qPCR) of antimicrobial peptide (AMP) and Toll pathway genes.
- In vivo antibiotic efficacy testing.
Main Results:
- N. circulans infection led to rapid mortality in B. mori larvae (within 48-96 hours).
- Infection caused melanization and increased hemolymph PO activity, with increased bacterial load and decreased hemocyte counts.
- Upregulation of AMP genes (Bmdefensin-B, Bmgloverin-3) and BmToll-2 observed in response to infection.
- Tested antibiotics (tetracycline, imipenem, ceftriaxone, ampicillin, clindamycin) showed varying therapeutic effects.
Conclusions:
- Bombyx mori larvae serve as a suitable and effective infection model for N. circulans.
- The silkworm model can be utilized for screening potential therapeutic agents against N. circulans.
- This research contributes to understanding host-pathogen interactions and developing strategies against antibiotic-resistant bacteria.
