Empyema due to Gemella morbillorum Is Diagnosed by 16S Ribosomal RNA Gene Sequencing and a Phylogenetic Tree Analysis: A Case Report and Literature Review.

We report a case of empyema due to Gemella morbillorum. In this case, an analysis of the aspirate from the pleural effusion revealed empyema and evidence of a Gram-positive coccal bacteria. A biochemical identification system labelled the bacteria as 'unclassified', although we initially suspected the bacterium to belong to the Streptococcus species. 16S ribosomal RNA (16S rRNA) gene sequencing and a phylogenetic tree analysis of the isolated strain confirmed the presence of Gemella morbillorum. To ascertain the true incidence of Gemella species in empyema, 16S rRNA gene sequencing should be used when the standard conventional biochemical methods fail to identify the organism or it identifies it with a low degree of reliability.