Presentation Title

Leveraging bacterial interactions to fight infections: Staphylococcus aureus and Acinetobacter spp.

Faculty Mentor

Maria Soledad Ramirez

Start Date

18-11-2017 10:00 AM

End Date

18-11-2017 11:00 AM

Location

BSC-Ursa Minor 56

Session

Poster 1

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Although bacteria are commonly studied in isolation, research has shown that bacteria often act in communities. In humans, polymicrobial infections are not uncommon, and often increase morbidity and mortality. In this study, we observed how two distant pathogens belonging to the group of “ESKAPE” species can work cooperatively or competitively to affect their hemolytic activity.

Hemolytic assays with and without the presence of distantly related cell-free-conditioned-media (CFCM) were performed with six different strains, two Staphylococcus aureus (LS1 and USA300) and four Acinetobacter spp. (A118, A42, A23, and A47). Optical density of the supernatant at 540nm and 570nm was used as a marker for hemolysis.

When grown alone, Acinetobacter A47 demonstrated moderate hemolytic activity. However, in the presence of S. aureus CFCM, A47 hemolytic activity was over 200% greater than when incubated alone. This increase in hemolytic activity was observed 3 hours after incubation, suggesting a significant collaborative interaction between the two strains. On the contrary, S. aureus USA300 showed reduced hemolytic activity when grown in the presence of A. baumannii A118, suggesting competitive inhibition. Hemolytic activity of S. aureus LS1 did not change when grown with A. baumannii A118.

Our results suggest that competitive interactions between specific pairs of bacterial strains may reduce activity of virulent strains. Additional experiments have been planned to identify interactions between other strains that may exhibit similar collaborative or competitive interactions. These results can help us to better fight infections and gain better insight into the fight against antibiotic resistance.

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Nov 18th, 10:00 AM Nov 18th, 11:00 AM

Leveraging bacterial interactions to fight infections: Staphylococcus aureus and Acinetobacter spp.

BSC-Ursa Minor 56

Although bacteria are commonly studied in isolation, research has shown that bacteria often act in communities. In humans, polymicrobial infections are not uncommon, and often increase morbidity and mortality. In this study, we observed how two distant pathogens belonging to the group of “ESKAPE” species can work cooperatively or competitively to affect their hemolytic activity.

Hemolytic assays with and without the presence of distantly related cell-free-conditioned-media (CFCM) were performed with six different strains, two Staphylococcus aureus (LS1 and USA300) and four Acinetobacter spp. (A118, A42, A23, and A47). Optical density of the supernatant at 540nm and 570nm was used as a marker for hemolysis.

When grown alone, Acinetobacter A47 demonstrated moderate hemolytic activity. However, in the presence of S. aureus CFCM, A47 hemolytic activity was over 200% greater than when incubated alone. This increase in hemolytic activity was observed 3 hours after incubation, suggesting a significant collaborative interaction between the two strains. On the contrary, S. aureus USA300 showed reduced hemolytic activity when grown in the presence of A. baumannii A118, suggesting competitive inhibition. Hemolytic activity of S. aureus LS1 did not change when grown with A. baumannii A118.

Our results suggest that competitive interactions between specific pairs of bacterial strains may reduce activity of virulent strains. Additional experiments have been planned to identify interactions between other strains that may exhibit similar collaborative or competitive interactions. These results can help us to better fight infections and gain better insight into the fight against antibiotic resistance.