目的 了解1~3月龄婴儿下呼吸道感染(LRTI)病原菌的分布及耐药情况,为临床合理选用抗生素提供依据.方法 选取2013年1~12月本院收治的患LRTI的1~3月龄婴儿622例,取痰标本送细菌培养.采用琼脂扩散敏感试验行药敏试验.结果 622份痰标本中共分离到菌株379株,检出率为60.9%,其中革兰阴性菌325株(85.8%),革兰阳性菌50株(13.2%),真菌4株(1.1%).革兰阴性菌主要为大肠埃希菌(31.1%)和肺炎克雷伯菌(18.2%),产超广谱β内酰胺酶(ESBLs)菌的检出率分别为48.3%和52.2%,且上述两种产ESBLs菌的平均耐药率为53%,对氨苄西林、头孢噻肟耐药率达100%,对碳青霉烯类抗生素均敏感.革兰阳性菌主要为金黄色葡萄球菌(10.0%),其中耐甲氧西林金黄色葡萄球菌检出比例较低(1.8%),但对β内酰胺类抗生素100%耐药.结论 1~3月龄婴儿LRTI的病原菌以革兰阴性菌:大肠埃希菌和肺炎克雷伯菌为主,产ESBLs菌检出率达48%以上,平均耐药率达53%以上,可指导临床首次经验性选药,以提高低龄婴儿的治疗有效率和生存率.

Objective To investigate the pathologic bacterial distribution and their antibiotic resistance in infants aged from 1 to 3 months with lower respiratory tract infection, so as to provide instructions for clinical application of antibiotics. Methods Induced sputum was extracted from 622 cases of hospitalized infants aged from 1 to 3 months with lower respiratory tract infection between January 2013 and December 2013, and microbial sensitivity test was performed with agar diffusion sensitivity test. Results A total of 379 (60.9%) strains of bacteria were isolated from induced sputum in the 622 infants. The Gram-negative strains were detected in 325 strains (85.8%), and the Gram-positive strains were found in 50 strains (13.2%) in the 379 strains. The others were Fungal strains (4 strains, 1.1%). The Gram-negative bacteria included Escherichia coli (31.1%) and Klebsiella pneumoniae (18.2%), with extended-spectrum β-lactamases (ESBLs) production of 48.3% and 52.2% respectively. The average rate of antibiotic resistance for ESBLs-producing bacteria was 53%. ESBLs-producing bacteria were highly resistant (100%) to ampicillin and cefotaxime, but sensitive to carbapenems. Staphylococcus aureus (10.0%) was the dominant bacteria in Gram-positive bacteria. A lower proportion of methicillin-resistant Staphylococcus aureus (1.8%) was observed, however the resistance rate of methicillin-resistant Staphylococcus aureus to β-lactam antibiotics were 100%. Conclusions Escherichia coli and Klebsiella pneumoniae are the main pathogenic bacteria causing lower respiratory tract infection in infants aged from 1 to 3 months. ESBLs-producing bacteria accounted for over 48%, and the antibiotic resistance rate were more than 53% in these infants. These results provide a basis for the first empirical clinical use of antimicrobial in infants with lower respiratory tract infection.