Sepsis: Group B strep declines, E. coli on the rise. (Tied to intrapartum antibiotics).

Early-onset group B streptococcal sepsis in very-low-birth-weight infants has decreased since the introduction of widespread intrapartum antibiotic therapy But there has been a corresponding increase in early-onset sepsis caused by ampicillin-resistant Escherichia coli, according to results of a large retrospective study.

The increase suggests that, while the therapy has achieved its desired effect, it is also associated with the development of antibiotic-resistant gram-negative bacteria, which can cause even more dangerous neonatal infections, reported Dr. Barbara J. Stoll of Emory University in Atlanta, and her colleagues (N. Engl.J. Med. 347[4]:240-47, 2002).

The investigators studied the records of 13,053 very-low-birth-weight (VLBW) infants born in centers of the neonatal research network of the National Institute of Child Health and Human Development.

The first cohort consisted of 5,447 infants born between 1998 and 2000; the second cohort consisted of 7,606 infants born between 1991 and 1993. All of the infants weighed between 401 and 1,500 g and had at least one blood culture in the first 3 days of life.

The rate of early-onset sepsis was similar in the earlier and later cohorts (19% vs. 15%). The pathogens responsible for those infections, however, changed significantly From the earlier cohort to the later cohort, the rate of group B streptococcal infections declined from 5.9 to 1.7/1,000 live births, but the rate of E. coli infections increased from 3.2 to 6.8/1,000 live births.

In the later cohort, gram-positive organisms caused about 40% of the infections, with group B streptococcus causing the majority--about 11 %. Gram-negative organisms caused more than 60% of the infections, with E. coli causing ...