Mario Feldman
Washington University in St Louis, MO·Microbiology & Immunology
Hospital bacteria that shrug off antibiotics are a growing problem, and Acinetobacter baumannii is among the worst. It survives on dry surfaces, forms biofilms, and causes pneumonia, bloodstream infections and catheter-associated urinary tract infections in critically ill patients.
- Fields
Microbiology & Immunology
Biochemistry
Medicine & Clinical Research
- Topics
Acinetobacter baumannii
antibiotic resistance
multidrug resistance
- Grants
- 4 known grants, through Jun 2031
What they work on
- Determine the structure and biosynthesis of PGR, the newly identified sugar receptor found in nearly all pathogenic Acinetobacter strains, and test its contribution to adherence and infection.
- Dissect how the binding protein of the broad host-range phage StAb3 recognizes PGR, and determine why the phage attaches to about 90% of A. baumannii strains but replicates well in only some.
- Map the reach of phenylacetic acid signaling in A. baumannii using reporter assays and gene expression profiling under antibiotic and oxidative stress, and measure intracellular PAA levels and the regulatory proteins involved.
- Test whether strains unable to regulate PAA levels lose virulence, using mouse models of catheter-associated urinary tract infection and lung infection.
- Define the roles and regulation of the Csu, Abp1 and Abp2 chaperone usher pili in acute and chronic respiratory infection models, and identify the host sugars that Csu binds.
- Characterize how the adhesin InvL binds fucosylated glycans to drive adhesion and invasion of primary epithelial cells and lung organoids, including its structure with and without bound sugars.
- Characterize the Dual Membrane-spanning Anti-sigma factor family, regulators that appear to span both bacterial membranes, and test how they control outer membrane vesicle production in Bacteroides.
- Define the role of BT_3341, whose loss abolishes vesicle formation, and identify additional machinery components, then visualize vesicle production in vivo and test its importance for bacterial fitness and colonization.
More about the research
Three projects attack this pathogen from different angles: how it senses and tolerates stress, how it grips and enters human tissue, and whether bacteria-killing viruses can be used against it. A fourth project turns to Bacteroides, a helpful gut bacterium, and asks how it releases the membrane bubbles it uses to communicate with its surroundings.
Why it matters
Multidrug-resistant A. baumannii is a World Health Organization critical-priority pathogen that threatens ventilated and catheterized patients. This work could broaden phage therapy beyond single strains, reveal a stress pathway whose disruption resensitizes bacteria to existing antibiotics, and support sugar-targeted treatments that block attachment without antibiotics. Understanding how gut Bacteroides make vesicles may eventually inform vesicle-based therapies for conditions involving gut imbalance, such as inflammatory bowel disease.
Known grants
From NIH and NSF research grants. Labs often have other funding we can't see.
Closest labs
Scott J. Hultgren
Washington University in St Louis, MO·Microbiology & Immunology
Determine how shape changes in bacterial adhesins control attachment, comparing FimH of uropathogenic E. coli and Klebsiella, the pectin-binding YehD and the fibrinogen-binding Abp2D of Acinetobacter using structural biology, molecular dynamics and biochemistry.
Ana Flores-Mireles
University of Notre Dame, IN·Microbiology & Immunology
Characterize how Candida albicans hyphal morphology, its filamentous virulent form, and the host immune signals MIP-1α and IL-17A modulate catheter-associated urinary tract infection in the bladder.
Jose Lemos
University of Florida, FL·Microbiology & Immunology
Uncover the regulatory mechanisms that let Streptococcus mutans tolerate high zinc, focusing on ZccE, a zinc-exporting pump unique to this species, and its regulator ZccR, using genetic and mutational approaches.
The school
Washington University in St Louis: 97 labs on PI Pages, $1.2B a year on research, 365 research doctorates a year.
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