Enterobacter kobei
Enterobacter kobei is a species of Gram-negative, facultatively anaerobic, motile, rod-shaped bacterium in the family Enterobacteriaceae. It belongs to the Enterobacter cloacae complex, whose members can be difficult to distinguish using routine phenotypic tests or 16S rRNA gene sequencing. Strains have been recovered from human clinical specimens and environmental samples.
Taxonomy
The specific epithet kobei means "of Kobe", referring to Kobe, Japan. The type strain, NIH 1485-79 (DSM 13645; JCM 8580), was isolated from the blood of a patient with diabetes.
Characteristics
Cells are Gram-negative, motile rods, and the species is facultatively anaerobic. The type-strain culture has been reported to grow between 10 and 41 °C. Reported metabolic characteristics include fermentation of glucose and lactose, utilization of citrate, and reduction of nitrate.
Species-level identification within the E. cloacae complex may require analysis of genes such as hsp60 or whole-genome sequencing. In a study of 183 clinical isolates of the complex collected from eight hospitals in South Korea, 25 isolates were identified as E. kobei by hsp60 sequence analysis.
Clinical significance and antimicrobial resistance
Enterobacter kobei has been associated with hospital-acquired bloodstream and urinary tract infections. During an outbreak in a neonatal intensive care unit in Nepal, the bacterium was recovered from the blood cultures of 11 neonates, five of whom died. Whole-genome sequencing showed that 10 of the 11 isolates were clonal. The outbreak isolates carried antimicrobial resistance genes including blaAmpC and mcr-10 and displayed reduced susceptibility to carbapenems and colistin.
Antimicrobial resistance genes do not necessarily produce the same susceptibility phenotype in every strain. An environmental strain isolated from a domestic kitchen sink in China carried plasmid-borne mcr-10.1 but remained susceptible to colistin; it was resistant to several other antibiotics, including cefazolin, cefoxitin, and fosfomycin.