# Optimization of therapeutic mAbs to carbapenem resistant Klebsiella clone ST258

> **NIH VA I01** · NORTHPORT VA MEDICAL CENTER · 2022 · —

## Abstract

Carbapenem resistant Klebsiella pneumoniae (CR-Kp) bacteria are the most common gram-negative
multidrug-resistant bacteria in US hospitals. CR-Kp cause predominantly pneumonia, sepsis and urinary tract
infections and, in military personnel, complicated invasive wound infections as well. Most patients acquire this
pathogen in health care associated settings. Soldiers are at risk because they commonly have prolonged stays
in hospitals and rehabilitation centers when they recover from injuries they sustained in combat. Mortality of
invasive CR-Kp infections is high and commonly over 50%. One problem is that most CR-Kp infections are
diagnosed too late and empiric treatment with antibiotics like polymyxin is toxic and also compromised by
emerging resistance even to these antibiotics. The goal of this application is to optimize two existing lead
monoclonal antibodies (mAbs) that bind to the diverse polysaccharide capsule (CPS) of CR-Kp. Both clade 1
and clade 2 CPS-specific IgG mAbs are available and are expected to cover the majority of CR-Kp strains
especially those that belong to the more virulent clade 2 of the clonal group CG258 group. Based on others
and our published experience we propose several strategies to test these mAbs. Three aims are proposed. In
Aim 1 we propose to generate isotype switch variants of CR-Kp specific mAbs and investigate relevance of
FcɣR binding in vivo. In Aim 2 we will identify the epitopes of the lead mAbs, and identify the best isotypes of
the candidate mAbs with respect to protective efficacy. We will also test combinations of CR-Kp specific mAbs
with antibiotics for optimal protection. Finally, in Aim 3 we will use a murine gut colonization model to
investigate if antibiotic-induced dissemination in colonized mice can be prevented by treatment with CPS-
specific mAbs.

## Key facts

- **NIH application ID:** 10427224
- **Project number:** 5I01BX003741-04
- **Recipient organization:** NORTHPORT VA MEDICAL CENTER
- **Principal Investigator:** Bettina Fries
- **Activity code:** I01 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2022
- **Award amount:** —
- **Award type:** 5
- **Project period:** 2019-01-01 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10427224

## Citation

> US National Institutes of Health, RePORTER application 10427224, Optimization of therapeutic mAbs to carbapenem resistant Klebsiella clone ST258 (5I01BX003741-04). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10427224. Licensed CC0.

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