Enterococcus dispar

Enterococcus dispar is a species of Gram-positive, facultatively anaerobic bacteria belonging to the genus Enterococcus. It was first isolated from human clinical samples and described as a novel species in 1991 by Collins and colleagues.^[1]

The species name dispar is derived from Latin, meaning "different" or "unequal", reflecting its distinction from other enterococcal species based on phenotypic and genotypic characteristics.^[2]

Enterococcus dispar was delineated as a separate species within the genus Enterococcus based on differences in 16S rRNA gene sequences and other phenotypic traits. The type strain is designated as E18-1 and is deposited under multiple culture collection numbers, including ATCC 51266 and DSM 6630.^[3]

Enterococcus dispar cells are ovoid-shaped, measuring approximately 0.6–2.0 μm in length, and typically occur in pairs or short chains. They are non-motile, non-spore-forming, and exhibit a thick peptidoglycan cell wall characteristic of Gram-positive bacteria. The species grows optimally at 37 °C under microaerophilic conditions and is catalase-negative.^[4]

The genome of the type strain ATCC 51266 has been sequenced, revealing a genome size of approximately 2.81 Mb with a GC content of 37.17%. The genome comprises 2,630 coding sequences, including genes associated with carbohydrate metabolism, stress response, and potential virulence factors.^[5]

While initially isolated from human clinical specimens, E. dispar has also been detected in various environmental sources, including traditionally fermented foods. For instance, strain CoE-457-22 was isolated from Montenegrin dry sausage, indicating the species' presence in food microbiota.^[6]

Although less commonly associated with human disease compared to other enterococcal species, E. dispar has been isolated from clinical samples, suggesting potential opportunistic pathogenicity. Its role in human health and disease requires further investigation.