The effect of immune modulation of Streptococcus constellatus SC10 strain upon Acinetobactor baumannii infection

- Preventing colonization may be a better therapeutic choice using microbiota to protect against A. baumannii transmission.
- S. constellatus frequently isolated from oral cavity was selected for study to check if its guards against A. baumannii.
- In a mouse model, administration of S. constellatus SC10 was able to control the weight lose induced by A. bumannii.
- In treated group, different cytokine after SC10 strain induction remarkably controlled the infection and induced more sIgA.
- Study suggests that SC10 L16 have potential immunomodulating effect which is able to regulate cytokines and sIgA response.

Acinetobacter baumannii is a tiny, plump and rod-shaped Gram-negative coccobacillus, notorious as an opportunistic pathogen, which is now being considered by CDC as a serious public health threat. Preventing colonization may be a better therapeutic choice using microbiota to protect against A. baumannii transmission. Human microbiota not only regulates immune homeostasis as well provides essential health benefits therefore discovering the interface due microbiota in host immune system will allow to recognise novel immuno- or microbe-based therapies. Streptococcus constellatus frequently isolated from oral cavity was selected for this study to check if its guards against A. baumannii by improving the immune response and the immune signalling pathway. In a mouse model we explored various parameters which include mouse body weight, internal organ weight, level of sIgA and different cytokine changes to evaluate its prophylactic effect against A. baumannii. Administration of S. constellatus SC10 was able to control the weight lose induced by A. bumannii infection in both the protected and treated groups. Particularly resistant against infection was more in treated group where the different cytokine following administration of SC10 strain remarkably controlled the infection and induced more sIgA production. The level of different interleukins IL-4, IL-10, IL-12 and IFN-γ was suppressed in treatment and protected group after exposure of S. constellatus. The excretion of sIgA following infection was many folds high in both group treated and protected groups Study suggests that SC10 L16 have potential immunomodulating effect which is able to regulate cytokines and sIgA response at the early phase of infection and modulate the further progress of clinical symptoms during infection.