| Objective: Streptococcus pneumoniae(SP)is the most common pathogen of respiratory tract infections in children and is a major cause of infant and child mortality worldwide.Due to the overusing antibiotics these days,SP with macrolide-resistance has shown high prevalence rate,while the rate of penicillin-resistance is also increasing steadily.Moreover,studies have shown multi-drug resistant SP strains all over the country.All these drug-resistance SP has caused great difficulties in clinical treatment.Hence,clinic study on SP is critical.SP infection has shown significant clinical differences in different area and different population.Up to date,there is only a few studies of children’s lower respiratory tract SP infection clinical characteristics.The published data is mostly from large tertiary hospitals and lack of research data in County-level primary hospitals.The current study focuses on studying children’s lower respiratory tract SP infection from different age groups in countylevel hospitals.Specifically,we analyzed the differences in SP-drugresistance and clinical changes,as well as clinical features of SP mixed infection with other pathogen in target population over a 3 years period.Our aims are as following: 1.Understand the clinical features of children with SP lower respiratory tract infection in county hospitals,analyze age specific characteristics,which would be beneficial in prevention and early treatment of SP infection.2.Understand the sensitivity and drug resistance of SP to general antibiotics in county hospitals,analyze the drug resistance prevalence,which would be beneficial in guiding clinical application of antibiotics.3.Understand the features of lower respiratory tract infection in children with SP and mixed infection in county hospitals,analyze the clinical characteristics,which would provide scientific data for making prevention strategies and measurements.Methods: A retrospective study for January 2015 to December 2017 was carried at Pediatric Department in Jinjiang City Hospital.Target population are hospitalized lower respiratory tract infection children from 28 days to 14 years old with sputum culture positive for S.pneumoniae.All enrolled patients have complete case data,including the drug sensitivity test results.1.Study the clinical features of SP lower respiratory tract infection in children of different age groups: analyze general situation,admission time,clinical diagnosis,clinical symptoms,signs,laboratory results and other related auxiliary examinations.2.Study the changes of SP-resistance in 3 years period: analyze the sensitivity,intermediation rate and drug resistance rate of SP to 7 different types of antibiotics.3.Study the mixed infection in children with respiratory tract infection: compare the pathogen difference in different age groups,analyze the difference of clinical symptoms and signs,laboratory test results and chest radiographs between SP mono-infection and mixed infection.Results:1.Clinical situation of SP lower respiratory tract infection in children of different age groups: 1.1 Epidemiological characteristics:(1)Gender and age difference: total 610 pediatric patients were enrolled,including 399 males(65.4%)and 211 females(34.6%),with male to female ratio of 1.89:1.The youngest patient is 1 year and 9 days old,the oldest patient is 9 years and eleven months old;279 cases(46.7%)are 28d~1 years old,231 cases(37.9%)are ≥1~3 years old,87 cases(14.3%)≥3~5 years old),13 cases(2.1%)≥ 5~14 years old.The incidence is mainly infants and young children <3 years old.(2)Seasonal month distribution differences: the incidence of Streptococcus pneumoniae infection is different in different seasons,with 218 cases(35.7%)in spring,123 cases(20.2%)in summer,132 cases(21.6%)in autumn,and 137 cases in winter(22.5)%).During the three-year period,the number of cases varied from month to month with the most cases being March and April(76 cases each),with the least being August(33 cases).The most incidence are in March and April of spring.(3)There was no difference in disease classification: total 610 children with SP lower respiratory tract infection were enrolled,with pneumonia 448 cases(73.4%),including 387 cases(86.4%)of bronchial pneumonia and 61 cases(13.6%)of lobar pneumonia;with trachea-bronchitis 162 cases(26.6%).Among bronchial pneumonia,363(93.8%)were mild acute bronchial pneumonia,16(4.1%)with persistent pneumonia,and 8(2.1%)with severe pneumonia.There was no difference in the classification of SP lower respiratory tract infections in children at different age groups.The cases of persistent pneumonia and severe pneumonia were mostly at the 28d~1 year old group,but not in the children over 5 years old.1.2 Clinical differences:(1)body temperature in different age groups: 450 cases(73.8%)had fever,including 62 cases(10.2%)with low fever,133 cases(21.8%)with moderate fever,255 cases with high fever(41.8%).The average fever duration is(2.88±2.39)days,wutg the shortest being 0.5 days,and the longest being 15 days.Of the 450 children with fever,441(98%)were <5 years old,and the groups of early childhood and preschool age had higher incidence than that of infants.Trending chi-square statistics shows that the child’s fever is more severe as the child’s age increases.Children in early childhood and preschool age have a longer fever duration than infants.(2)clinical manifestations in different age groups: All children have cough.The older the child,the higher the incidence of dry cough and the lower the incidence of wet cough.≥5~14 years old group had a higher incidence of dry cough and a lower incidence of wet cough compared with the 28d~1 year old group and ≥1~3 years old group.Infants and young children are more likely to have wheezing and diarrhea than preschool and school-age children.The older the patients were,the higher percentage of lungs without arpeggios,the less likely it is to have abnormal lung hearing.While,the younger the patients were,the easier it is to observe abnormal lung hearing.(3)Differences in laboratory tests: Among 610 children with SP respiratory infection,325(53.3%)of elevated peripheral blood leukocyte counts(>10×109/l),288(47.2%)of elevated peripheral blood neutrophils percentage,444(72.8%)of elevated CRP(>8 mg/l).The preschool age and school age patients has higher incidence of elevated neutrophil percentage compared to infants and young children.The trending chi-square showed that the older the patients were,the higher incidence of elevated neutrophil percentage.(4)Differences in chest radiographs: 23(3.8%)cases had no abnormal chest radiographs,and 247(40.5%)cases had abnormal chest radiographs findings,which includes 68 cases(11.1%)of pulmonary consolidation(large-scale density increase),and 272 cases(44.6%)of bronchial pneumonia(small patchy density).According to chest radiographs findings,there was no significant differences of different lung segments involvement in children of different age groups.2.The changes of SP-drug-resistance in three consecutive years: This study included 610 colonies of S.pneumoniae with complete drug sensitivity test data,including 205 colonies from 2015,193 colonies from 2016 and 212 colonies from 2017.Sensitivity [colony number(%)] to seven antimicrobial agents of these 610 SP colonies were tested: linezolid 610(100%),vancomycin 610(100%),levofloxacin 610(100%),penicillin 602(98.7%),compound sulfamethoxazole 154(25.2%),clindamycin 13(2.1%),and erythromycin 4(0.7%).No resistance to penicillin G was found in 3 years.According to the chi-square analysis,there was no significant difference in the resistance rate,intermediate rate and sensitivity rate of SP in 7 different antibacterial drugs in this study.3.Analyze mixed infection in children with SP respiratory tract infection:(1)Overall situation of mixed infection: 610 children with lower respiratory tract infection of S.pneumoniae were detected with 344 cases(56.4%)had other pathogen infections,including 104 cases(17.0%)with pneumonia mycoplasma infection and 240 cases(39.3%)with other bacterial infections.Among the other bacteria detected,there were 121 cases(19.8%)of Moraxella catarrhalis,97 cases(15.9%)of Haemophilus influenzae,15 cases(2.5%)mixed of Haemophilus influenzae and Moraxella catarrhalis,5 cases(0.8%)of Staphylococcus aureus,1 case(0.2%)of Acinetobacter baumannii,and 1 case(0.2%)of Escherichia coli.(2)There are differences in mixed pathogen infections at different age groups: there are higher incidence of MP infection in children over 1 year old and higher incidence of SP infection in children under 1 year old.(3)Differences in clinical features of mixed infections: The fever history of the SP mixed with Mycoplasma pneumoniae group was longer than that of the SP alone group or SP mixed with other bacterial groups.Neutrophil percentage in SP mixed with Mycoplasma pneumoniae group and SP mixed with other bacterial groups were higher than that in the SP alone group.The level of CRP in SP mixed with other bacterial groups was higher than that in the SP alone group.The study found that there were no significant differences at mixed pathogen infection with regards to gender,heat duration over 7 days,fever,cough duration,wheezing,lung voice,average length of hospital stay,and chest radiograph.Conclusion: 1.Children with lower respiratory tract infections has higher incidence in males than females,and most of them occured in the spring of March and April.The age of onset is mainly infants and young children <3 years old.The pathogenic outcome is mainly pneumonia.Most of the infections are not serious.Severe infections and prolonged unhealed are mainly seen in infants and young children.Children with SP lower respiratory tract infection has cough and fever as the main clinical manifestations.Children under 5 years old have higher fever incidence,but mainly low fever.Children over 5 years old have higher incidence of high fever,longer heat history,dry cough,and lung auscultation is less audible.Infants and young children are more likely to have wheezing and diarrhea than preschool and school-age children.The percentage of neutrophils increased more significantly in children over 3 years of age;peripheral blood leukocyte count,C-reactive protein value,and chest radiograph showed no significant age difference.2.In this study,most of the children with SP lower respiratory tract infections had mixed infections,mainly Moraxella catarrhalis,Haemophilus influenzae,and Mycoplasma pneumoniae.The detection rate of Mycoplasma pneumoniae mixed infection was higher in children over 1 year old.Infants who had high fever have a higher probability of SP infection alone;longer heat history may suggest mixed infection with Mycoplasma pneumoniae,and a significant increase in the percentage of neutrophils may suggest mixed infection with other pathogens.A significant increase in CRP levels may suggest a combination of other bacterial infections.3.From 2015 to 2017,the sensitivity rate of Streptococcus pneumoniae to linezolid,vancomycin and levofloxacin were all 100% in Jinjiang Hospital of Fujian Province,the sensitivity rate to penicillin G was 98.7%,and the mediation rate was 1.3%.No resistance SP strain was found.Penicillin is still the first choice for the treatment of SP respiratory tract infection in children in this area;the resistance rate to compound sulfamethoxazole is 65.4%,and the study has shown high resistance rate of SP to clindamycin and erythromycin,97.4 % and 99.2% respectively,with the highest resistance rate to erythromycin.There was no significant change during the 3 years in the sensitivity,intermediation rate,and drug resistance rate of SP against 7 antimicrobial agents.4.For children with SP lower respiratory tract infections,clinical features,laboratory tests,and radiological findings play a very limited role in predicting mixed infections. |
