| Objective: To expand our understanding of the bacterial epidemiology in different aged children with acute respiratory tract infection in Soochow area.At the same time, the status of staphylococcus aureus and the rate of resistance to different antibiotics were calculated.Methods: 14994 nasopharyngeal secretion samples were collected from hospitalized children with acute respiratory infection,admitted from November 2005 to October 2014.The positive cases were retrospectively consulted, collected,and analyzed. So we can understand the distribution of various bacteria in different years,different seasons and different ages.363 strains of Staphylococcus aureus were isolated from 14994 cases,334 strains of which will be applied by broth microdilution susceptibility test.The study pointed out the epidemic features and resistance to different antibiotics of Staphylococcus aureus.Results: The total bacteria positive rate of 14994 nasopharyngeal secretion samples was 26.32% in children with acute respiratory infection during the nine years, with the first bacteria pathogen was Streptococcus pneumonia,Haemophilus influenze and Moraxelle catarrhalis following. The bacteria positive rate was different in different years,different seasons and different age groups children.During the nine years, bacteria detection rate was significantly higher during November 2013 to October 2014 than that of other years. Throughout the year, the detection rate of Streptococcus pneumoniae was the first, and the epidemic season of Streptococcus pneumonia was winter,in the same time, Moraxelle catarrhalis was detected mostly in winter; Escherichia coli, Haemophilus influenze was autumn; Pseudomonas aeruginosa was summer; Staphylococcus aureus, Klebsiella pneumoniae was detected all of the year and there was not obvious seasonal difference. The children was infected mostly by Streptococcus pneumoniae in all age groups of children with acute respiratory infection,and the age group of~60 months had the highest Streptococcus pneumoniae positive rate.The group of ~60 months was the high incidence age of Moraxelle catarrhalis infection, ~12 months was the high incidence age of Haemophilus influenzae, ≤6 months was the high incidence age of Escherichia coli,Staphylococcus aureus,Klebsiella pneumoniae,Pseudomonas aeruginosa and Acinetobacter baumannii.Sputum culture positive rate in children who prehospitally unused antibiotics is higher than that used the antibiotics. No matter the length of using antibiotics, streptococcus pneumoniae detection rate is still the first.The length of using antibiotics has a relationship with the constitution of bacteria. Staphylococcus aureus positive detection rate was decreasing with using antibiotic increasingly,while Streptococcus pneumoniae and Acinetobacter baumannii detection rate was increasing with the extension of course; Staphylococcus aureus, Escherichi coli detection rate had a downward trend with the extension of course.363 strains of Staphylococcus aureus was isolated from November 2005 to October 2014(2.42%),334 strains of which was broth microdilution susceptibility tested. Methicillin resistant staphylococcus aureus was 18.86%(63/334),while methicillin sensitive staphylococcus aureus was 81.14%(271/334). The group of under 2 years was the high incidence age of Staphylococcus aureus infection, mostly ≤6 months. The results of 334 strains of microdilution susceptibility tested showed that : Staphylococcus aureus had resistance all above 40% to erythrocin each year; Resistance rate to penicillin G was high,during 89.66% to 100%; Resistance rate to clindamycin was all more than 20% from November 2006 to October 2011,with a peak 28.95%; Resistance rate of MRSA(90.47%) was significantly higher than that of MSSA(52.77%).MRSA and MSSA both had high resistance rate topenicillin G, but were sensitive to cotrimoxazole, gentamicin, ciprofloxacin, rifampicin,there were no difference significantly.The two groups were not resistant to linezolid, vancomycin.Conculsion:(1) Streptococcus pneumonia was the first bacterial pathogens causing children respiratory infection,followed by Haemophilus influenze and Moraxelle catarrhalis.(2) In different ages、different years and different seasons, the kind and the positive detection rate of bacterial pathogens were different.(3) The length of using antibacterial drugs and duration of course had certain influence to the positive rate of bacteria and bacterial composition.(4)Enterobacteriaceae and none ferment were popular in ≤6 months children.(5) Staphylococcus aureus was popular throughout the year, peak age for≤6 months.(6) There were no bacterium resistant to linezolid,vancomycin. |
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