# Consequences of Direct Viral-Bacterial Interactions

> **NIH NIH R56** · ST. JUDE CHILDREN'S RESEARCH HOSPITAL · 2021 · $531,058

## Abstract

The synergy between Streptococcus pneumoniae and influenza during co-infection has long been
recognized. Our data indicate that this synergy is operative on a physical level, as we provide evidence of
influenza A virus (IAV) binding to the surface of S. pneumoniae, providing fitness benefits to both
pathogens. We have strong experimental evidence that IAV directly binds to S. pneumoniae, facilitating
enhanced bacterial adhesion in vitro and enhanced colonization and dissemination in vivo. This intimate
interaction between virus and the bacterial surface is not limited to S. pneumoniae, as binding was
observed with multiple bacterial inhabitants of the human respiratory tract including species of
Staphylococcus, Moraxella, and Haemophilus. The relationship between IAV and the bacterial surface is
mutually beneficial, as IAV bound to specific bacterial species demonstrate dramatically enhanced
environmental stability, with IAV retaining infectivity during desiccation only when in complex with bacteria.
Our long-term goal is to gain a greater understanding of the synergies operative during IAV-bacterial co-
infections during both invasive disease and transmission. The overall objective of this proposal is to gain a
mechanistic understanding of how direct IAV-pneumococcal binding occurs and the impact of these
interactions on host-pathogen interactions. We hypothesize that the direct interactions between IAV and
bacteria are mediated by specific factors of both pathogens and that the direct interactions between
bacteria and IAV impact respiratory infection. The interkingdom interplay between respiratory pathogens
may be underappreciated as a mechanism underlying viral–bacterial synergy during respiratory infection.

## Key facts

- **NIH application ID:** 10437204
- **Project number:** 1R56AI155614-01A1
- **Recipient organization:** ST. JUDE CHILDREN'S RESEARCH HOSPITAL
- **Principal Investigator:** Juan Cesar Federico Ortiz-Marquez
- **Activity code:** R56 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $531,058
- **Award type:** 1
- **Project period:** 2021-07-20 → 2023-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10437204

## Citation

> US National Institutes of Health, RePORTER application 10437204, Consequences of Direct Viral-Bacterial Interactions (1R56AI155614-01A1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10437204. Licensed CC0.

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