Dataset Information

Dynamic Pneumococcal Genetic Adaptations Support Bacterial Growth and Inflammation during Coinfection with Influenza.

ABSTRACT: Streptococcus pneumoniae (pneumococcus) is one of the primary bacterial pathogens that complicates influenza virus infections. These bacterial coinfections increase influenza-associated morbidity and mortality through a number of immunological and viral-mediated mechanisms, but the specific bacterial genes that contribute to postinfluenza pathogenicity are not known. Here, we used genome-wide transposon mutagenesis (Tn-Seq) to reveal bacterial genes that confer improved fitness in influenza virus-infected hosts. The majority of the 32 genes identified are involved in bacterial metabolism, including nucleotide biosynthesis, amino acid biosynthesis, protein translation, and membrane transport. We generated mutants with single-gene deletions (SGD) of five of the genes identified, SPD1414, SPD2047 (cbiO1), SPD0058 (purD), SPD1098, and SPD0822 (proB), to investigate their effects on in vivo fitness, disease severity, and host immune responses. The growth of the SGD mutants was slightly attenuated in vitro and in vivo, but each still grew to high titers in the lungs of mock- and influenza virus-infected hosts. Despite high bacterial loads, mortality was significantly reduced or delayed with all SGD mutants. Time-dependent reductions in pulmonary neutrophils, inflammatory macrophages, and select proinflammatory cytokines and chemokines were also observed. Immunohistochemical staining further revealed altered neutrophil distribution with reduced degeneration in the lungs of influenza virus-SGD mutant-coinfected animals. These studies demonstrate a critical role for specific bacterial genes and for bacterial metabolism in driving virulence and modulating immune function during influenza-associated bacterial pneumonia.

SUBMITTER: Smith AP

PROVIDER: S-EPMC8208518 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:Influenza A virus (IAV) predisposes individuals to secondary infections with the bacterium Streptococcus pneumoniae (the pneumococcus). Infections may manifest as pneumonia, sepsis, meningitis or otitis media (OM). It remains controversial as to whether secondary pneumococcal disease is due to the induction of an aberrant immune response or IAV induced immunosuppression. Moreover, as the majority of studies have been performed in the context of pneumococcal pneumonia, it remains unclear how far these findings can be extrapolated to other pneumococcal disease phenotypes. Here, we demonstrate that the viral hemagglutinin (HA) mediates bacterial OM by inducing a pro-inflammatory response in the middle ear cavity in a replication-dependent manner. Importantly, our findings show that it is the inflammatory response that mediates pneumococcal replication; not viral suppression of the immune system or epithelial damage. This study provide the first evidence that HA induced inflammation drives pneumococcal replication in the middle ear cavity, which has important consequences to the treatment of pneumococcal OM. Five-day old C57BL/6 mice were colonised intranasally (i.n.) with 2M-CM-^W103 colony forming units (CFU) of S. pneumoniae EF3030Lux in 3 M-BM-5Ls of PBS. Alternatively, mice were mock-infected with an equivalent volume of phosphate buffered saline (PBS). At 14-days of age, infant mice were infected i.n. with 20 plaque forming units (PFU) (PR8/34, Cambridge/34 and WSN/33) or 102.5 PFU (all other virus strains) of egg-grown IAV in 3 M-BM-5Ls of PBS. Viral doses were selected to ensure a reproducible infection with minimum morbidity and no mortality. Six days post-IAV infection, mice were euthanised and organs were collected for analysis. Six independent biological replicates (where both ears from one mouse were pooled to create one sample) were used for each condition and analyzed using the NimbleGen platform (12M-CM-^W135K Mouse Gene Expression Arrays, Roche Nimblegen, USA). Indirect labeling, hybridization and washing was performed according to the manufacturerM-bM-^@M-^Ys instructions. Array images were acquired with a NimbleGen MS200 scanner, and images were processed with NimbleScan software using the RMA algorithm. Data was processed using Arraystar (DNASTAR, USA) with default settings as described in the manual. Differential expression tests were performed with a moderated T-test implemented in Arraystar, followed by FDR correction of the P values (Q-values) according to the method of Storey and Tibshirani

Dataset Information

Dynamic Pneumococcal Genetic Adaptations Support Bacterial Growth and Inflammation during Coinfection with Influenza.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets