The Impact Of Bacterial Colonization On Prognosis And Outcome Of Children With Bronchiolitis Induced By Respiratory Syncytial Virus

Objective:Wheezing disease is one of the most common respiratory diseases in infants and children, usually induced by viruses. The impact of bacteria on wheezing is not clear yet. Recent studies suggest that asthmatic children are often associated with bacterial colonization or infection. In this study, by retrospective analysis, we tried to clarify the impact of bacteria colonization on the development and prognosis of bronchiolitis induced by respiratory syncytial virus.Method:480 cases with hospitalized bronchiolitis between January 2008 to December 2008 in Respiratory ward of Children's Hospital, Chongqing Medical University were retrospective analysized. All cases in accordance with the detection of viruses and bacteria were divided into four groups: RSV+B+; RSV+B-; RSV-B+; RSV-B-, to learn about the difference among these groups with the condition in the hospital, and follow-up all these patients about their prognosis in one year after recovered. Result:71% of the 480 cases diagnosed as bronchiolitis were men, and women account for 29%. The onset age was between 1 and 19 months, the average age of 5.29±3.39 months. The peak season of bronchiolitis was on November and December. Bacterial colonization in respiratory cases accounted for 55.83% of all cases, mainly to be Gram-negative bacteria, accounting for 67.16%, including Haemophilus parainfluenzae, Klebsiella pneumoniae and Escherichia coli bacteria etc. The total of virus infection was 313 cases, accounting for 65.21% of all cases, including respiratory syncytial virus infection in 288 cases, accounting for 92.01%. Other viruses included parainfluenza virus infection in 10 cases, 1 case of influenza virus infection, adenovirus infection in 2 cases.Both of virus and bacterial detected positive was accounted for 36% of the proportion of all children. The severity and duration of the RSV+B+ group was higher than the RSV+B- group (P<0.05), the severity of the RSV-B+ group was higher than the RSV-B- group (P<0.01).Cases with RSV detected positive were more serious than that RSV detected negative (P<0.01). However, the latter group had a longer duration (P<0.05). Each group contained some degree of allergy history and family history of asthma in children, however, no significant difference between these groups.Follow-up results showed that the percentage of the RSV+B+ group with recurrent wheezing was 42%, which was higher than the RSV+B- group (36%). Compared with the RSV+B- group, the RSV-B- was more likely with recurrent wheezing. At the same time,wheezing was more likely induced by the respiratory tract infection.Conclusion:Airway bacterial colonization in the infants with viral induced wheezing might increase the severity and extend the course of disease with asthmatic disease, while increased the risk of wheezing within one year after the recurrence. Non-RSV viruses might be more likely cause the occurrence of recurrent wheezing in children.