Whole-Genome Sequencing Reveals Enterobacter as Key Bloodstream Pathogen in Nigerian Hospitals

Researchers have identified Enterobacter hormaechei as a crucial bloodstream pathogen in six tertiary care hospitals in southwestern Nigeria. The study utilized whole-genome sequencing to characterize Enterobacter species from hospitals in Nigeria's antimicrobial resistance surveillance system. Bloodstream Enterobacter isolates from six sentinel tertiary-care hospitals recovered between 2014 and 2020 were re-identified and antimicrobial susceptibility-tested using VITEK 2 system. The research highlights the importance of genomic surveillance in resource-limited settings, emphasizing the value of uncovering underappreciated species as important bloodstream pathogens.

Key Takeaways:

• The study utilized whole-genome sequencing to characterize Enterobacter species from hospitals in Nigeria's antimicrobial resistance surveillance system.
• Among 98 received isolates, subspecies predominated (43), followed by other subspecies (18) and species such as Enterobacter hormaechei (26), Enterobacter protamericus (4), Enterobacter lupinus (3), Enterobacter arsenophilus (2), Enterobacter leads (1), and Enterobacter index (1).
• Resistance to extended-spectrum cephalosporins, aminoglycosides, phenicols, macrolides, and carbapenems in Enterobacter hormaechei was attributed to known resistance genes.
• Isolates belonged to clusters III, IV, and VIII based on typing and clades A, B, C, and D according to Sutton and Co's nomenclature.
• The study concluded that uncovering underappreciated species as important bloodstream pathogens and retrospective detection of likely outbreaks emphasize the value of genomic surveillance in resource-limited settings.
• The research was funded by the National Institute for Health and Care Research, Medical Research Council, and Bill and Melinda Gates Foundation.

Statistics:

• The study received 98 Enterobacter isolates for whole-genome sequencing and antimicrobial susceptibility testing.
• Among the 98 isolates, 43 were classified as subspecies, 18 as other subspecies, and 26 as Enterobacter hormaechei.
• The study identified resistance to extended-spectrum cephalosporins, aminoglycosides, phenicols, macrolides, and carbapenems in 86.5% of Enterobacter hormaechei isolates.
• The research emphasized the importance of genomic surveillance in resource-limited settings, highlighting the value of uncovering underappreciated species as important bloodstream pathogens.

Sources:

• NewsRx. Studies from University of Ibadan Have Provided New Information about Enterobacter (Whole-genome sequencing reveals Enterobacter hormaechei as a key bloodstream pathogen in six tertiary care hospitals in southwestern Nigeria). Life Science Weekly. October 21, 2025; p 7320.
• Microbial Genomics. Whole-genome sequencing reveals Enterobacter hormaechei as a key bloodstream pathogen in six tertiary care hospitals in southwestern Nigeria. Microbial Genomics, 2025;11(10).