分析重庆市垫江县儿童社区获得性急性下呼吸道感染(ALRI)致病菌特点及其耐药性情况，为临床合理使用抗菌药物提供依据。

选择2013年7月1日至2014年6月30日，在重庆市垫江县人民医院儿科住院治疗的1 960例确诊为社区获得性ALRI的患儿为研究对象，并根据年龄将其分为3组：<1岁组(n＝936)，≥1～3岁组(n＝662)及≥3～14岁组(n＝362)。采用临床常规痰液采集方法，在使用抗菌药物治疗前，采集痰液标本进行接种、分离培养、细菌鉴定及药敏试验。分析比较不同年龄段患儿痰培养结果的致病菌阳性率及其构成比差异，总结主要致病菌对常用抗菌药物的耐药情况。本研究遵循的程序符合重庆市垫江县人民医院人体试验委员会制定的伦理学标准，得到该委员会批准，分组征得受试对象监护人知情同意，并与监护人签署临床研究知情同意书。3组患儿性别构成比及起病至入院时间比较，差异无统计学意义(P>0.05)。

①3组患儿痰培养结果的致病菌阳性率任意2组间比较，均为年龄小组较年龄大组高，且差异有统计学意义(P<0.001)。②痰培养结果的主要致病菌前4位按照由多至少的顺序排列依次为肺炎链球菌528株(33.7%)、流感嗜血杆菌332株(21.2%)、卡他莫拉菌234株(14.9%)及金黄色葡萄球菌133株(8.5%)。③3组间痰培养结果的主要致病菌构成比比较，肺炎链球菌比例随患者年龄增加而增加，而常见革兰阴性(G^－)杆菌比例，则随年龄增加而减少，且差异均有统计学意义(P<0.017)；卡他莫拉菌比例在≥1～3岁组较<1岁组高，3组中<1岁组患者金黄色葡萄球菌比例最高，且差异均有统计学意义(P<0.001)；3组间流感嗜血杆菌比例比较，差异无统计学意义(P>0.05)。④年龄越大致病菌种类越少(9种)，年龄越小则致病菌种类越多(20种)。⑤除流感嗜血杆菌外，本组其余主要致病菌(肺炎链球菌、卡他莫拉菌、金黄色葡萄球菌、肺炎克雷伯菌肺炎亚种、大肠埃希菌及副流感嗜血杆菌)对部分常用抗菌药物耐药率>50.0%，并以金黄色葡萄球菌最甚，其对多种常用抗菌药物耐药且耐药率>90.0%。

垫江县儿童社区获得性ALRI病原菌以细菌为主，且细菌耐药现象突出；致病菌以肺炎链球菌最多；年龄越小致病菌种类越多，且金黄色葡萄球菌及G^－杆菌比例越高。因此应建立本地区病原菌监测体系进行流行病学调查，用于指导临床合理使用抗菌药物。

To analyze the characteristics and drug resistance of pathogenic bacterium of community acquired acute lower respiratory infection(ALRI) in children in Dianjiang county, Chongqing, and to provide basis of rational use of antibacterials for clinical practice.

A total of 1 960 children who made definite diagnosis of community acquired ALRI and hospitalized in department of Pediatrics, Dianjiang People's Hospital of Chongqing from July 1, 2013 to June 30, 2014 were chosen as study subjects.They were divided into 3 groups: <1 year old group(n=936), ≥1-3 years old group(n=662) and ≥3-14 years old group(n=362)in accordance with age stage. Using clinical routine sputum collecting method to collect sputum and doing vaccination, separation culture, bacteria identification and drug sensitive test before use antibacterials.Compare the differences of positive rate and constituent ratio of pathogenic bacterium of sputum culture results in different age stages and to summarize the drug resistance of main pathogenic bacterium to frequently used antibacterials.The study protocol was approved by the Ethical Review Board of Investigation in Human Being of Dianjiang People's Hospital of Chongqing.Informed consent was obtained from the parents of each participant.There were no significant differences among three groups in gender constituent ratio and time from onset to admission(P>0.05).

①Positive rate of pathogenic bacterium of sputum culture in younger age groups were higer than those in elder age groups, and there were significant differences(P<0.001). ②Top 4 main pathogenic bacterium of sputum culture were 528(33.7%) strains of Streptococcus pneumonia, 332(21.2%) strains of Hemophilus influenza, 234(14.9%) strains of Moraxelle catarrhalis and 133(8.5%) strains of Staphylococcus aureus in descending order. ③Among 3 groups, Streptococcus pneumonia proportion in sputum culture increased with age while common Gram negative (G^-)bacillus proportion decreased with age, and there were significant differences(P<0.017); Moraxelle catarrhalis proportion in ≥1-3 years old group was higher than that in <1 year old group, and Staphylococcus aureus proportion in <1 year old group was the highest one in 3 groups, and there were significant differences (P<0.001); There were no significant differences among 3 groups in Hemophilus influenza proportion(P>0.05). ④There were 9 pathogenic bacterium species in ≥3-14 years old group, and 20 species in <1 year old group.The older of children, the less pathogenic bacterium species in sputum culture.⑤Except drug resistance rates of Hemophilus influenza, drug resistance rates of other main pathogenic bacterium, including Streptococcus pneumonia, Moraxelle catarrhalis, Staphylococcus aureus, Pneumonia subspecies of K. Pneumoniae, Escherichia coli and Hemophilus parainfluenzae on some frequently used antibacterials were more than 50.0%, especially Staphylococcus aureus, it had a variety of frequently used antimicrobial drug resistance and their drug resistance rates were more than 90.0%.

The main disease producing germ of community acquired ALRI in children in Dianjiang county, Chongqing were bacteria, and bacterial drug resistance is obvious. Streptococcus pneumoniae infection rate was the highest.The younger children, the more pathogenic bacterium species in sputum culture, and the higher of infection rates of Staphylococcus aureus and G^- bacillus. We should establish monitoring system to monitor disease producing germ of community acquired ALRI in children in Dianjiang county to proceed epidemiological investigation and to guide the clinical rational use of antibacterials.