Objective To determine EOS ampicillin-resistant (AR) epidemiology and risk factors associated with ampicillin-resistant infection in newborns in the era of GBS prophylaxis.
Methods This was a retrospective analysis between 2002 and 2009, from microbiology laboratory database and hospitalization reports in one neonatal care unit. EOS was defined by a positive culture results for blood or cerebrospinal collection from infants aged ≤ 7 days, hospitalized in the university hospital of Poitiers. Data were analyzed using Chi(2), Student’s test and binary logistic regression in univariate and multivariate models.
Results EOS was identified in 30 cases. Nineteen infants (63.3%) were preterm with GA ≤ 35 weeks. The overall mortality rate was 23.3%. Escherichia Coli (E. Coli) and GBS accounted respectively for 40% and 26.3% of the cases. Eighteen infants (62.1%) were infected with an AR pathogen. Among E. Coli isolated, 81.8% were AR. E. Coli was most frequently isolated in preterm infants, (10 cases; 52.6%), while SGB was predominant (7 cases; 63.6%) in term infants. EOS AR proportion was significantly higher among preterm than term infants (85% vs 10%, p≤0,001). In the AR group, GA was significantly lower, maternal age, intrapartum exposure to antibiotics and membrane rupture was higher, (p<0.05). In multivariate models, GA ≤ 35SA was an independent predicted factor associated with AR EOS (OR 28 [95%CI, 1.77–444.09]).
Conclusion E. Coli and AR EOS were predominant in preterm infants with GA ≤ 35 weeks. GA ≤ 35 weeks is an independent predicted factor of AR EOS.