Genomic Insights into Two Colistin-Resistant Strains Isolated from the Stool of Preterm Neonate During the First Week of Life.

is a major opportunistic pathogen frequently associated with nosocomial infections, and often poses a major threat to immunocompromised patients. In our previous study, two (K36 and B13), which displayed resistance to almost all major antibiotics, including colistin, were isolated. Both isolates were not associated with infection and isolated from the stools of two preterm neonates admitted to the neonatal intensive care unit (NICU) during their first week of life. In this study, whole genome sequencing was performed on these two clinical multidrug resistant . We aimed to determine the genetic factors that underline the antibiotic-resistance phenotypes of these isolates. The strains harbored , , and genes conferring resistance to cephalosporins, carbapenems, and fluoroquinolones, respectively, but not harboring any known plasmid-borne colistin resistance determinants such as . However, genome analysis discovered interruption of gene by insertion sequences gaining insight into the development of colistin resistance. The observed finding that points to a scenario of potential gut-associated resistance genes to Gram negative () host in the NICU environment warrants attention and further investigation.