Impact of influenza virus infection on lung microbiome in adults with severe pneumoniaOriginal paper
Karen Pendergrass is a microbiome researcher specializing in microbiome-targeted interventions (MBTIs). She systematically analyzes scientific literature to identify microbial patterns, develop hypotheses, and validate interventions. As the founder of the Microbiome Signatures Database, she bridges microbiome research with clinical practice. In 2012, based on her own investigative research, she became the first documented case of FMT for Celiac Disease, four years before the first published case study.
Read MoreWhat was studied?
This study compared the lung bacterial communities of severe pneumonia patients who were influenza virus positive versus negative. The goal was to see how influenza infection shapes lung flora. Bronchoalveolar lavage fluid was sequenced using the 16S rDNA V3-V4 region. Nasopharyngeal swabs were tested for eight respiratory viruses and nine bacteria. Diversity was assessed with Chao1, Shannon, and Simpson indices. LEfSe identified taxa differing between groups. It was a case-control design.
Who was studied?
The cohort was 84 adults with severe community-acquired pneumonia from three sentinel hospitals in China, enrolled between 2017 and 2020. This was a human clinical study. Forty-two were influenza positive and negative for other pathogens, and 42 were negative for all pathogens tested. Groups were matched one to one by age and sex. Each group was 78.6 percent male. Mean age was 64 in the influenza-positive group and 59 in the negative group (p=0.079).
What were the most important findings?
The dominant genera were Streptococcus, Klebsiella, and Escherichia-Shigella in influenza-negative patients, versus Acinetobacter, Streptococcus, and Staphylococcus in influenza-positive patients. Streptococcus pneumoniae was the most abundant species in the influenza-negative group. Acinetobacter baumannii was the most abundant species in the influenza-positive group. LEfSe found Klebsiella more abundant in influenza-negative patients. Alpha and beta diversity did not differ significantly between the two groups.
What are the greatest implications of this study?
Severe pneumonia patients with influenza appear more susceptible to certain bacteria, especially Acinetobacter baumannii, a multidrug-resistant nosocomial pathogen. This argues for closer bacterial surveillance in influenza cases. The dominance of A. baumannii over the usual Streptococcus pneumoniae in flu-positive patients is notable. It may reflect a virus-bacteria interaction. The cross-sectional design cannot establish causation or timing, and the sample was modest. The proposed influenza-Acinetobacter interaction needs further mechanistic study.