Study On Distribution And Drug Resistance Of The Isolated Bacteria From Children With Acute Respiratory Infection

Objective: To investigate the distribution and durg resistance of the isolated bacteria from children with acute respiratory infection, the purpose is to direct pediatrian rational using antimicrobial agents in order to control and decrease the development of bacterial resistance.Methods: Between January 2006 and February 2007, 930 children with acute respiratory infection (ARI) from out-patients and new in-patients were enrolled, of 364 with acute upper respiratory infection (AURI), and of 566 with acute lower respiratory infection (ALRI). The group of AURI obtained with pharyngeal swab cultures unused antimicrobial agents or used antimicrobial agents orally one to two times, the group of ALRI obtained with sputum and bronchoalveolar lavage fluid (BALF) cultures used antibacterial agents by intravenous transfusion > 3 days. The isolated bacteria were identified by ATB system (Bio-Merieux , France). Antimicrobial susceptibility testing was carried out by means of Kirby-bauer. The data was analysed by SPSS10.0.Results: Of 404 isolates from 930 respiratory tract secretion, total positive rate was 43.4%. The positive rate of bacterial cultures from pharyngeal swab, sputum and BALF was 36.3%, 45.8% and 92.6% respectively. Gram negative bacilli and gram positive cocci was accounted for 79.0% and 21.0% respectively. Haemophilus and Streptococcus accounted for 34.7% and 15.6% respectively. Haemophilus influenzae, Haemophilus parainfluenzae and Streptococcus pneumoniae accounted for22.5%, 12.1% and 7.4% respectively. In isolates from AURI, Haemophilus influenzae, Haemophilus parainfluenzae and Streptococcus pneumoniae accounted for 43.9%, 22.0% and 9.1% respectively, Escherichia coli, Klebsiella spp. and Nonfermenters accounted for 4.5%, 8.3% and 3.0% respectively. In isolates from ALRI, Haemophilus influenzae, Haemophilus parainfluenzae and Streptococcus pneumoniae accounted for 12.1%, 7.4% and 6.6% respectively, Escherichia coli, Klebsiella spp. and Nonfermenters accounted for 16.9%, 13.2% and 21.8% respectively. In gram negative bacilli, Haemophilus influenzae and Haemophilus parainfluenzae was accounted for 28.5% and 15.4% respectively; in gram positive cocci, Streptococcus was accounted for 74.1%, Streptococcus pneumoniae was accounted for 35.3%. Of 25 isolates from BALF, 20 isolates were Streptococcus, other isolates were gram negative bacilli. The resistant rate to ampicillin and TMP-SMZ of Haemophilus was 29.3% and 32.9% respectively, the resistant rates to amoxicillin-clavulanic acid and cefalotin, cefaclor, cefuroxime were from 10.0% to 12.1%, while the resistant rate to cefotaxime was 5.7%. The resistant rates to ampicillin (p<0.001), amoxicillin-clavulanic acid (p<0.05), cefaclor (p<0.05), tetracycine (p<0.05), and TMP-SMZ (p<0.001) of Haemophilus were significant different between AURI group and ALRI group, ALRI group were higher than AURI group. The resistant rates to antimicrobial agents were no significant difference between Streptococcus pneumonia and other Streptococcus (p>0.05). The resistant rate to penicillin of Streptococcus was 12.7%, the resistant rates to erythromycin, clindamycin, tetracycline and TMP-SMZ were from 54.0% to 84.1%, the resistant rate to levofloxacin was 14.3%, and the resistant rate to cefotaxime was 6.3%.Conclusions: In Dalian, Haemophilus was the main prevalent isolates of children with ARI during surveillance. The resistant rate to ampicillin of Haemophilus was higher. Gram negative bacilli was the main isolated bacteria. Using antimicrobial agents in longer term and in larger dose could lead to alteration of normal flora in respiratory tract, gram negative bacilli in higher proportion, as well as increasing bacterial resistant rate. In gram positive cocci, Streptococcus was in higher proportion. The main pathogenic bacteria of severe and refractory pneumonia were Streptococcuswith stronger resistance at present.