Neonatal Escherichia coli infections: concerns regarding resistance to current therapy

Currently recommended antibiotic treatment of suspected neonatal sepsis is ampicillin and an aminoglycoside. Recently, we observed increasing ampicill in and gentamicin resistance in strains of Escherichia coli isolated from n eonates at our institution. We therefore reviewed clinical and laboratory r ecords of all neonates with systemic infection, hospitalized from 1994 thro ugh 1998, from whom E. coli was isolated from blood and/or cerebrospinal fl uid. The influence of perinatal variables (e.g. rupture of foetal membranes > 24 h, group B Streptococcus (GBS) colonization, urinary tract infection during pregnancy and the use of antepartum and/or intrapartum antibiotics), and neonatal variables (e.g. gestational age, age at onset of sepsis (earl y: less than or equal to 72 h, late: >72 h), number of E. coli septic recur rences, and associated underlying medical and/or surgical conditions) on an timicrobial susceptibilities of invasive E. coil isolates was studied. Twen ty-three neonates with invasive E. coli infection were identified; most [19 (83%)] presented as late-onset sepsis (LOS). Ampicillin-resistant E. coli were isolated in 75% and 53% of neonates in the early- and late-onset group s, respectively. Gentamicin resistance was found in 50% of early-onset seps is (EOS) isolates compared with 16% in the late-onset group. Isolates from two neonates with EOS were resistant to both ampicillin and gentamicin. One neonate with EOS and three with LOS had recurrent E. coil sepsis; all isol ates were ampicillin-resistant and one was gentamicin-resistant. All these neonates were initially treated with ampicillin and gentamicin. Both groups had associated underlying medical and/or surgical conditions (50% early-on set, 47% late-onset). Maternal GBS colonization occurred in 2 (50%) versus 3 (16%) of EOS and LOS cases, respectively. All GBS colonized women receive d intrapartum ampicillin prior to delivery. Conclusions: Ampicillin and gentamicin resistance is emerging in neonatal E . coil isolates from invasive infection. Current empiric management of neon atal sepsis requires re-evaluation given Changing antimicrobial susceptibil ities.