The isolates reported herein were recovered as part of such a surveillance program of intensive care unit (ICU) surfaces at a tertiary care hospital in Pakistan in 2016. As many pathogens can persist on surfaces for extended periods of time, microbiological and molecular surveillance of high-contact surfaces in health-care settings is an important feature of effective infection control and prevention strategies (Russotto et al., 2015). The danger from these infections is exacerbated by the higher levels of antibiotic resistance harbored by nosocomial pathogens compared to their community-associated relatives (Horcajada et al., 2013). The hospital built environment is a key source of nosocomial pathogens, which can cause high mortality infections in vulnerable patient populations (Oberauner et al., 2013). The biochemical and phylogenomic analysis indicate strains BP-1(T) and BP-2 represent a novel species from a new genus within the Enterobacteriaceae family, for which the name Superficieibacter electus gen. Average Nucleotide Identity analysis indicates that BP-1(T) and BP-2 are the same species. Phylogenomic analysis of the shared genes between BP-1(T), BP-2 and type strains from Kluyvera, Citrobacter, Escherichia, Salmonella, Kosakonia, Siccibacter and Shigella indicate that BP-1(T) and BP-2 isolates form a distinct branch from these genera. The biochemical utilization scheme of BP-1(T) using the Analytic Profile Index for Enterobacteriaceae (API20E) indicated its enzymatic functions are unique within the Enterobacteriaceae but most closely resemble Kluyvera spp., Enterobacter cloacae and Citrobacter koseri/farmeri.

The 16S rRNA gene sequence of strain BP-1(T) had the highest identity to Citrobacter farmeri CDC 2991-81(T) (98.63%) Citrobacter amalonaticus CECT 863(T) (98.56%), Citrobacter sedlakii NBRC 105722(T) (97.74%) and Citrobacter rodentium NBRC 105723(T) (97.74%).

To more precisely determine the taxonomic identity of BP-1(T) and BP-2, we employed a biochemical and phylogenomic approach.

Both strains were unidentified using the bioMerieux VITEK MS IVD v2.3.3 and Bruker BioTyper MALDI-TOF mass spectrometry platforms. Two Gram-negative bacilli strains, designated BP-1(T) and BP-2, were recovered from two different Intensive Care Unit surfaces during a longitudinal survey in Pakistan.

Electus dg 16