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Updated: Apr 23, 2026
A Blood-Free Diet to Rear Anopheline Mosquitoes
Published on: January 31, 2020
Serratia marcescens and Enterobacter cloacae exhibit differential population dynamics in Anopheles gambiae s.l after
Seraphim N A Tetteh1, Stephanie N A S Addo1, Jewelna Akorli2
1Department of Parasitology, Noguchi Memorial Institute for Medical Research, University of Ghana, Legon-Accra, Ghana.
Background:
Serratia marcescens and Enterobacter cloacae are associated with Anopheles gambiae mosquitoes and have been found to possess anti-plasmodial properties, making them suitable candidates to explore for bacteria-mediated disease/vector control. Their natural growth trends in the mosquito particularly after the host has fed on sugar and blood is required to deepen our understanding of how they can be effectively utilized in vector/disease control.
Methods:
In this study, we employed a time-course experiment to investigate the dynamics of S. marcescens and E. cloacae in An. gambiae s.l mosquitoes over a 48-h period after feeding. Absolute bacterial counts were estimated using quantitative PCR (qPCR) on cDNA obtained from total RNA from mosquitoes and, with standard curves from bacterial isolates. A generalized additive mixed model (GAMM) was employed to investigate the interaction effects of diet and time on the bacteria trends while accounting for non-linear trends and repeated measures (random effects for ID).
Results:
We show that E. cloacae are constitutively ~ 2000-fold more abundant in both sugar and blood fed mosquitoes than S. marcescens. In sugar-fed mosquitoes, both bacterial species are generally in equilibrium except at 2 h after the sugar meal when S. marcescens dips significantly (p = 0.03). E. cloacae remain remarkably stable at ~ 107 CFU/mL over 24-48 h in sugar- and blood-fed mosquitoes, while S. marcescens demonstrate non-linear growth dynamics (p = 0.02) in response to blood meal characterized by a sharp increase from a lower initial baseline (103 CFU/mL) to a peak of 105 CFU/mL at ~ 19 h post-blood meal, representing ~ 100-fold increase in its abundance.
Conclusion:
Contrary to the general perception that members of Enterobacteriaceae increase after the mosquito blood feeds, our results provide evidence that Serratia but not Enterobacter naturally proliferates following a blood meal. This highlights that the choice of microbes for disease/vector biocontrol strategies must be informed by the specific growth kinetics of the candidate species. This work also hints on a multi-species consortium approach as a probable robust strategy for biocontrol.
