Uropathogenic Bacteria Linked to Deadly Disease in Preterm Infants

Necrotizing enterocolitis (NEC) is an intestinal disease that afflicts about one in ten extremely premature infants and is fatal in nearly one-third of cases.

The premature infant gut is believed to react to colonizing bacteria, causing damage to the intestinal walls and severe infection. An association has been described between necrotizing enterocolitis and a subset of Escherichia coli bacteria, called uropathogenic E. coli (UPEC) that colonize the infant gut.

Scientists at the University of Massachusetts Medical School (Worcester, MA, USA) and their colleagues obtained stool samples from a cohort of 166 infants: 144 preterm and 22 that had been carried to term from hospitals in Cincinnati, Ohio, and Birmingham, Alabama. The team sequenced the infants' stool and developed metagenomic analysis tools to identify the bacteria colonizing each infant. Previous work had already identified Enterobacteriaceae, a family of bacteria that includes E. coli, as potentially associated with NEC.

The team singled out UPEC as the E. coli type most strongly linked to infants who developed NEC. In the study cohort, 27 of the infants developed NEC, all preterm. The disease was fatal in 15 of those cases. UPEC was found in 44% of the infants who developed NEC, compared to only 16% of the 111 infants who survived without developing NEC. Although the team did not address the question of where UPEC in an infant's gut might originate, they did observe an association between vaginal delivery and death from NEC in these extremely preterm infants. Metagenomic multilocus sequence typing analysis further defined NEC-associated strains as sequence types often associated with urinary tract infections, including ST69, ST73, ST95, ST127, ST131, and ST144.

Doyle V. Ward, PhD, a microbiologist and coauthor of the study, said, “Many infants do have UPEC in their gut. It may be that they're colonized when they pass through the birth canal, and this could be a source of risk. We just don't know yet. It's important to realize that infants also acquire many beneficial bacteria from their mothers during vaginal birth and it's likely that the good bacteria have a role in preventing NEC.” The study was published on March 15, 2016, in the journal Cell Reports.

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