(765c) Elucidating Bacterial Interactions in the Vaginal Microbiome Using Microfluidic Droplet Technology

Elucidating Bacterial
Interactions in the Vaginal Microbiome Using Microfluidic Droplet Technology

Corine Jackman¹ (corinemj@umich.edu), Xiaoxia (Nina) Lin^1,2 (ninalin@umich.edu)

¹Department of
Chemical Engineering, University of Michigan, Ann Arbor, MI 48109

²Department of
Biomedical Engineering, University of Michigan, Ann Arbor, MI 48109

There is increasing evidence suggesting
that the bacteria in the human vagina, referred to collectively as the vaginal
microbiome (VMB), plays fundamental roles in womenÕs health and susceptibility
to diseases.
For instance, bacterial vaginosis (BV), the most common vaginal infection in women
of reproductive age in the United States, is characterized by disturbances in
the VMB where lactic acid bacteria level is reduced dramatically by an
overgrowth of various other bacteria. BV is associated with an increased risk of preterm birth, which has accounted for approximately 75 percent of
perinatal deaths in the United States¹. Women with BV also have an increased susceptibility for
contracting sexually transmitted infections, such as HIV. The question of how
the diverse microorganisms in VMB interact with one another and with their host
functionally remains largely unanswered. This is due in part to the immense
ecological complexity and the challenge in isolating microbes using
conventional cultivation methods.

Microfluidic droplet technology has emerged as a new approach for compartmentalizing
cells from microbial communities to perform assays, measure growth, and detect
interactions in individual nano- or pico-liter droplets. Advantages of this approach include high-throughput
experimentation, and reduced space, time, chemical reagent and labor
requirement. In this work, we use microfluidic droplet co-cultivation to investigate pairwise
interaction between two vaginal bacteria, specifically Gardnerella vaginalis and a Lactobacillus
species. G. vaginalis
is associated with BV and Lactobacillus
species are believed to promote health by producing lactic acid and
reducing pH in the vagina. A previous study demonstrated a severe killing
effect on G. vaginalis after
incubation in supernatant of Lactobacilli.
We investigate this interaction by co-cultivating these species in
micro-droplets and comparing growth in the bi-culture verses monocultures. Droplets
after incubation under appropriate condition are analyzed through Fluorescent In
Situ Hybridization
(FISH) using specific probes that hybridize to the 16s rRNA
of targeted species. More cell growth in droplets with monocultures in
comparison to droplets with bi-cultures indicate a negative
interaction. This work demonstrates the effectiveness of using droplet
co-cultivation for investigating microbial interactions in the VMB.

Reference:

1. McCormick, Marie C.
"The contribution of low birth weight to infant mortality and childhood
morbidity." New England journal of medicine 312.2
(1985): 82-90.