The relationship between lower respiratory tract infections and pathogenic bacteria of sputum in elderly patients

Objective To explore the relationship between lower respiratory tract infections and pathogenic bacteria of sputum in elderly patients.Methods 168 elderly patients with lower respiratory tract infections,who were hospitalized repeatedly for 216 times were subjected to sputum culture.The positive result was defined when a same bacterium was found after the culture for two or more than 2 times serially or 3 times intermittently.Results Of 873 sputum cultures 326 (37%) were positive,gram positive cocci were observed in 50 cultures (15.3%) and gram negative bacilli in 221 (67.8%).The antibiotic resistant rates were 10%～44% for pseudomonas aeruginosa to cephalosporins Ⅲ and piperacillin, and 11%～37% for Klebsiella pneumoniae to cephalosporins Ⅲ and amikacin.The positive rates of sputum culture in serious cases was higher,nosocomial infections was higher than that of community acquired.Conclusions Lower respiratory tract infections in elderly patients are mainly due to gram negative bacilli and the rates of resistance to antibiotics are increasing.