Table 2

Gram-negative species as percentages of all infant early-onset and late-onset bacteraemia (Gram-negative and Gram-positive) in high-income and low-income/middle-income countries*

High-income countriesEarly-onset disease (n=24 studies)Late-onset disease (n=25 studies)
Isolates, nProportion (95% CI)Isolates, nProportion (95% CI)
Escherichia coli145419.2% (15.6 to 23.4%)14187.34% (5.28 to 10.1%)
Klebsiella spp910.95% (0.36 to 2.49%)14015.28% (3.42 to 8.06%)
Pseudomonas spp400.22% (0.01 to 0.79%)4061.21% (0.75 to 1.92%)
Enterobacter spp160.08% (0.01 to 0.48%)7081.36% (0.64 to 2.88%)
Serratia spp10.00% (0.00 to 99.5%)2540.50% (0.23 to 1.11%)
Proteus spp40.03% (0.00 to 0.28%)280.03% (0.01 to 0.19%)
Salmonella spp0N/A40.00% (0.00 to 22.6%)
Citrobacter spp190.02% (0.00 to 0.43%)360.01% (0.00 to 0.17%)
Haemophilus spp1840.54% (0.18 to 1.62%)60.00% (0.00 to 0.25%)
Neisseria spp0N/A20.00% (0.00 to 2.43%)
Acinetobacter spp310.08% (0.01 to 0.57%)2070.28% (0.09 to 0.90%)
Moraxella spp0N/A70.00% (0.00 to 99.3%)
Other species or unspecified Gram-negative1801.41% (0.62 to 3.18%)2750.39% (0.14 to 1.03%)
Low-income/middle-income countriesEarly-onset disease (n=32 studies)Late-onset disease (n=30 studies)
Escherichia coli4817.50% (4.98 to 11.1%)4896.53% (4.50 to 9.39%)
Klebsiella spp79416.4% (11.5 to 22.7%)97415.0% (10.1 to 21.8%)
Pseudomonas spp2483.93% (2.04 to 7.44%)2322.81% (1.99 to 3.95%)
Enterobacter spp2031.76% (0.88 to 3.49%)1581.14% (0.55 to 2.34%)
Serratia spp360.12% (0.02 to 0.62%)670.12% (0.02 to 0.71%)
Proteus spp210.00% (0.00 to 1.61%)500.09% (0.01 to 0.52%)
Salmonella spp110.00% (0.00 to 10.9%)200.00% (0.00 to 17.4%)
Citrobacter spp470.12% (0.02 to 0.60%)750.10% (0.02 to 0.51%)
Haemophilus spp0N/A140.00% (0.00 to 99.1%)
Neisseria spp0N/A60.00% (0.00 to 97.4%)
Acinetobacter spp3182.33% (1.17 to 4.61%)3482.33% (1.20 to 4.46%)
Moraxella spp0N/A0N/A
Other species or unspecified Gram-negative1950.83% (0.29 to 2.37%)1841.28% (0.61 to 2.66%)
  • *Estimates obtained by random-effects meta-analysis; see online supplemental file 4 for heterogeneity statistics.

  • N/A, not available.