Analysis Of Distribution And Drug Resistance Of Lower Respiratory Tract Infection Pathogens In Respiratory Ward

Background and Objective: The lower respiratory tract infection is a common disease that seriously threatens human health and quality of life. As the widely use of antibiotic, and internal environment disturbance because of invasive examines and therapy, the kind of pathogens of lower respiratory tract infection have changed, and the number and degree of drug-resistant strains increased day by day, even multiple-resistance strains appear. That is why the morbility and mortality of lower respiratory infection keep high. The distribution of pathogens and resistance differ between different countries and regions. Comprehending the distribution and resistance characteristic of clinical commen pathogens of this region is important to make empirical anti-infective therapy plan, direct the rational use of antibiotic and improve the curative effect of infective disease. This article is designed to analyze the distribution and antimicrobial resistance of pathogens isolated from patients diagnosed as lower respiratory tract infection in respiratory ward of our hospital, and evaluate the accordant rate of initial empirical therapy and drug sensitive test, so as to offer the reference of antibiotics using for the physicians.Methods: This research collects 2434 cases who were diagnosed as lower respiratory tract infection in our respiratory department during January 2009-December 2010. Submit 1498 sputum and bronchoalveolar lavage fluid specimens,then identify the pathogens and do the drug sensitive test according to the standards of《National operation regulations of clinical laboratory》and NCCLS. Investigate the distributions and drug resistances of the pathogens isolated.Results: The survey shows that the submission ratio of respiratory tract specimens was 57.0%, the detection ratio was 28.6%. The submission ratio and detection ratio of ICU were 91.3% and 54.2%. A total of 429 strains of pathogenic bacteria were isolated. Among them 266 strains were gram negative bacilli(62.0%).The top six gram negative bacilli were Pseudomonas aeruginosa,Klebsiella pneumoniae,Acinetobacter baumannii,Stenotrop- homonas maltophilia,Escherichia coli and Enterobacter cloacae. 152 strains were fungus(35.4%), the main fungus were Candida albican. 11 strains were gram positive coccus(2.6%), the main gram positive coccus were Staphylococcus and Enterococcus. Gram negative bacillis were highest sensitive to carbapenem antibiotics and complex ofβ-Lactam Antibiotics/β-lactamase Inhibitors, followed by amikacin. The resistant ratio to penicillin, the first and second generational Cephalosporins, aztreonam, aminoglycosides antibiotics- gentamicin, qinolones antibiotics-ciprofloxacin were the most highest. Klebsiella pneumoniae and Escherichia coli were predominant strains of ESBLs-producing, whose isolating rate were 31.1% and 35.7% in this research. Whether ESBLs-producing or non-ESBLs- producing strains, all Klebsiella pneumoniae and Escherichia coli are sensitive to imipenem, meropenem and cefoperazone-sulbactam, resistant to ampicillin. The drug resistant of ESBLs-producing strains was much higher than non-ESBLs-producing strains. Gram positive coccus'resistant rate to frequently-used antibiotics is high generally. Linezolid and vancomycin keep good antimicrobial activity to gram positive coccus. The accordant rate of clinical initial empirical therapy and drug sensitive test in vitro is 40.4%. 15.9% cases'initial empirical therapy are not conform with drug sensitive test but patients'condition are improved after initial empirical therapy so go on the initial agents; 10.8% cases'initial empirical therapy are not conform with drug sensitive test and the initial therapy fail so change the antibiotic according to the test,in which Pseudomonas aeruginosa and Acinetobacter baumannii account for 26.7% and 23.3% respectively ;32.9% cases'drug sensitive test do not contain the drug which is used in initial empirical therapy.Conclusion: The submission ratio and detection ratio of respiratory department is low relatively, while ICU is better than general ward. Gram-negative bacilli are the most common pathogens of lower respiratory tract infection. The resistance of the different antimicrobial agent is different. Physicians should master the pathogens distribution and resistance character, then choose proper empirical antimicrobial agents with considering clinical condition of patients; According to the result of pathogen test and condition change after initial therapy, estimate whether the positive strain is responsible pathogen and analysis the difference between in vitro test and in vivo activity, so as to choose rational targeted therapy to infective disease. This group of data is important to guide the physicians of the respiration department to promote the rational use of antimicrobial agents.