OBJECTIVETo analyze the epidemiological characteristics and the bacterial pathogen composition of pneumonia among children under 5 years old in Ningbo.

METHODSIn 2013 February-April, we selected pediatric ward in three hospitals according to stratified cluster random sampling, and from which we collected all 57 556 hospitalized cases in January 2009-December 2012 period of children under 5 years old. A total of 16 740 medical records and bacterial spectrum records of pneumonia or bronchial pneumonia cases among children under 5 years old were described to calculate the proportions of children pneumonia or bronchial pneumonia hospitalized cases accounted for hospitalized children over the same period(referred to as proportions of pneumonia incidence), the detection rate of bacterial pathogens, proportions of bacterial spectrum, and to analyze the characteristics and bacterial pathogen composition of pneumonia among children under 5 years.

RESULTSThe proportions of children pneumonia in 2009-2012 were 26.16% (2 882/11 017), 31.23% (4 004/12 819), 29.35% (4 898/16 689) and 29.10% (4 956/17 031)(Z = 3.13, P < 0.01), and were in a downward trend by the increasing of age(Z = -113.74, P < 0.01). The proportions of children pneumonia of 0-5 age group were 50.71% (6 756/13 318), 26.60% (3 159/11 877), 24.17% (2 574 /10 648), 22.36% (2 509 /11 223) and 16.63% (1 745 /10 490). The proportions of children pneumonia with different season were 26.90% (3 725/13 850), 26.51% (3 788/14 287), 29.59% (4 442/15 011) and 33.21% (4 785 /14 408) (χ² = 198.77, P < 0.01). The proportions of severe children pneumonia of 0-5 age group were 1.10% (74/6 753), 0.47% (15/3 159), 0.19% (5 /2 574),0.08% (2 /2 509) and 0.06% (1 /1 745), with a downward trend by the age(F = 57.62, P < 0.01). The detection rate of Klebsiella pneumoniae, Haemophilus influenzae,Acinetobacter baumannii, Escherichia coli, Staphylococcus aureus, and Streptococcus pneumoniae was 19.3% (540/2 805), 16.4% (460/2 805), 13.6% (381/2 805), 11.9% (335/2 805), 11.5% (323/2 805) and 6.8% (192/2 805).

CONCLUSIONIn 2009-2012, the proportions of children pneumonia under 5 year old constituted a relatively high proportion in Ningbo city. Children under 1 year old were the major suffering group of pneumonia and severe pneumonia, which should be the key prevention group. The major bacterial pathogens of children's pneumonia in Ningbo are gram-negative bacteria.