| Objective:To investigate the distribution of bacterial pathogens in children with acute respiratory tract infections before using the antibiotics in Hunan,and to provide etiological evidence for clinical diagnosis and treatment of respiratory tract infections in children in the region.Methods:1.The 12 sentinel hospitals were set up in the different areas(including Changsha, Xiangtan, Yueyang, Changde, Hengyang, Shaoyang and Chenzhou regions) in Hunan province. The fixed personnel were trained by the ways of lectures, live demonstrations, the scene simulation,animation CD and error correction summary. Then unified examination after training make each specimen and the sentinel hospital patient data registration of homogenous level.2.During March-31-2012 to December-31-2014, Selected the children with acute respiratory tract infection and without the use of antibiotics as the research objects in 12 sentinel units in Hunan province.Nasopharyngeal swab samples of the research objects were collected to bacteria culture and their clinical data were analyzed statistically. The nasopharyngeal swab samples were collected within 24 hours, beforecollecting the samples, consent of the all families was asked and also got the approval from the hospital ethics committee.3. After collection, specimen quickly were sent to the department of laboratory of Hunan Provincial People’s Hospital(sampling outside the hospital were placed in transport medium tube, within 24 hours into Inspection), and immediately were inoculated on blood agar plate,China blue agar plate and chocolate agar plate, then placed in the temperature of 37 DEG, 5% CO2 environment culture 18 ~ 24 h. Selected the positive samples from medium individual colonies to do bacteria identification and drug sensitivity test. Identification of bacteria and drug sensitivity test are used French Merieux VITEK 2 compact automatic bacteria identification and drug sensitivity analysis system. VITEK 2detection system using a special test card for sensitivity test of bacteria identification, used for rapid identification of bacteria in human clinical specimens.Result:1.In this study from March 2012 to December 2014 nasal swab specimens were collected from 886 cases, in which 555 cases were male and 331 female cases. The male to female ratio was 1.68: 1. The age from one day old to 14 years old; mean age of all the research objects was calculated to be 33.35 months.2.Among 886 nasopharyngeal swab specimens from children with respiratory tract infection, 188(21.22%) cases had a positive bacterial culture. Streptococcus pneumoniae(8.24%) 、 Moraxella catarrhalis(3.05%)、Haemophilus influenzae(2.60%) were more common.3.The study subjects were divided into 5 different age groups by age points for ≤6 months,~ 12 months, ~36 months, ~60 months, >60 months. Each group of bacteria total detection rate was 31.54%,30.46%, 17.99%, 11.64% and 14.84% respectively. ≤6 months group’s bacteria detection rate is higher than the other 4 groups, there was statistically significant difference.(P< 0.05)4.From January 2013 to December 2014, 602 cases of specimen were collected, Out of which 148 cases had a positive bacterial culture. In2013 and 2014, the total bacteria positive detection rate was 18.45%(62/336) and 32.33%(86 / 266) respectively, while the positive detection rate of Streptococcus pneumoniae was 6.55% and 15.04% respectively.5.There was statistically significant differences in the rate of bacteria detection in different seasons. The bacteria positive detection rates In spring, summer, autumn and winter seasons were 26.02%, 10.77%,21.90% and 24.90% respectively, highest in Spring and lowest in Summer(P< 0.05). Detection of common bacteria in different seasons was also observed, Streptococcus pneumoniae, Haemophilus influenzae were mostly detected in spring, while Moraxella catarrhalis and Staphylococcus aureus in autumn.6.Different sentinel units sampling locations and culturing location distance was not same. Detection rate was different because of the difference of submission time of samples. The inspection time in one hour the sample bacteria positive rate reached 23.98%( 117/488);inspection time within 2 hours of bacterial samples positive detection rate for 19.40%(45/232); inspection duration of operation > 2 h of sample bacteria positive rate of 15.66%(26/166). For long inspection time,culture positive rate decreased, but the difference was not statistically significant(P>0.05).7.In this study, the main clinical symptoms of study object were fever(56.73%), cough(96.50%), expectoration(35.19%), and Sore throat(18.62%). Compared with those bacteria detected negative, children withbacteria detected positive were more likely to have fever, cough,expectoration, fatigue. Pulmonary rales was the most common signs,24.74% study object accompanied by pulmonary rales. But there were no significant difference between bacteria positive and negative children.White blood cell count(WBC) and C reaction protein(CRP) increased in44.47% and 28.78% study object respectively. While,WBC and CRP increased in 95.70% and 41.4% bacteria detected positive children respectively. Compared with those of the bacteria detected negative children, WBC and CRP of bacteria detected positive children were significantly increased(P>0.05).Conclusion:1.The most common bacterial pathogen of acute respiratory tract infections in Hunan province children is Streptococcus pneumoniae, then is Moraxella catarrhalis and Haemophilus influenzae.2. The detection rate of bacterial pathogens varies in different age and season..3. Acute respiratory tract infection caused by bacteria is more likely to lead to the increase of inflammatory index( including WBC and CRP). |
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