A Pathogen Survey In University Hospital's Adults With Community-Acquired Lower Respiratory Tract Infection During Autumn And Winter Of 2007-2008

ObjectiveTo investigate the pathogen and bacterial resistance in university hospital's adults with community-acquired lower respiratory tract infection during autumn and winter to help empirical antimicrobial chemotherapy, and to evaluate the role of the loop-mediated isothermal amplification(LAMP) technique in the pathogenic detection .Methods110 adult patients of community-acquired lower respiratory tract infections were from the first affiliated hospital of Nanchang University from september 2007 to february 2008. Pathogen were detected from the sputum samples by the routine bacterial culture and loop-mediated isothermal amplification technique. The bacterial susceptibility were tested by microdilution method.Results1. 110 LRTI accepted sputum culture, the bacterial positive rate was 50.9%(56).64 bacteria were isolated, including gram negative bacteria 65.6 % (42) ,in wich Acinetobacter baumannii and Pseudomonas aeruginosa were the most common pathogens (18.5% and 17.2 % , respectively) ;Gram positive bacteria 17.2 %(11); fungi17.2%(11).2..Bacterial resistance rates of 12 Acinetobacter baumannii were respectively Cefotetan, cefazolin and nitrofurantoin more than 90.0%; ampicillin 83.3%; Ciprofloxacin, ceftriaxone, cefepime and ampicillin / sulbactam 50.0%; ceftazidime, levofloxacin 41.7%; meropenem 28.6%; cefoperazone / Sulbactam, tobramycin, imipenem 25.0%; piperacillin / tazobactam 16.7%; amikacin 0. Bacterial resistance rates of 11 Pseudomonas aeruginosa were respectively compound sulfamethoxazole 85.7%; tetracycline 80.0%; ceftizoxime 75%; Cefotaxime 62.5%; ticarcillin, ticarcillin / clavulanic acid, ciprofloxacin, ceftriaxone 50.0%; tobramycin 37.5% levofloxacin 36.4 %; ceftazidime, Cefepime, amikacin 33.3%; imipenem 27.3 %; piperacillin 25.0%; Cefoperazone / Sulbactam 12.5 %; piperacillin / tazobactam 10.0 %; meropenem 9.1 %.3. 110 LRTI accepted LAMP technique, the microorganism positive rate was 83.7%(96).126 microorganism isolated from patients were respectively Acinetobacter baumannii 28.6% (36), Pseudomonas aeruginosa 15.9% (20), Klebsiella pneumoniae 14.3% (18), Mycoplasma pneumonia 13.5% (17), Streptococcus pneumoniae and Escherichia coli to 6.3 % (each eight), Haemophilus influenzae 5.6% (7), Staphylococcus aureus 4.8% (6), Stenotrophomonas maltophilia and Legionella bacteria 2.4 % (each three).4. LAMP technique has higher sensitivity (87.3%) in pathogen diagnosis for lower respiratory infection than the routine sputum bacterial culture (50.9%).Conclusions1.The pathogens isolated from university hospital's adult patients with community-acquired lower respiratory tract infection during autumn and winter are mostly bacteria(82.8-84.1%),atypical pathogens occupied 15.9%. 2.Acinetobacter baumannii has a high resistance rates to cefazolin, Cefotetan ampicillin. Pseudomonas aeruginosa has a high resistance rates to compound sulfamethoxazole, tetracycline and ceftizoxime; It is evident that the two bacteria are sensitive to piperacillin/tazobactam, cefoperazone/sulbactam, imipenem and meropenem .3. LAMP technique has more sensitivity in the pathogen diagnosis of lower respiratory infection and detect more rapidly than the routine sputum bacterial culture.