Pathogenic Bacteria and Their Antibiotic Susceptibility of 1 268 Sputum Specimens

Objective:To study the antibiotic susceptibility patterns of pathogenic bacteria in patients with lower respiratory tract infection (LRTI). Methods:Sputum specimens for bacterial culture were collected in sterile tubes from the patients with LRTI between Jan,2006 and Dec,2008. The subjects were divided into three groups according to different age:children group (6 months to 13 years old),adults group (14 to 64 years old),and senior group ( or =65 years old). Methods:A ratio of 39.8% patients were positively infected,of which Gram-negative bacteria accounted for 62.3%,gram-positive bacteria for 33.7%,fungi for 0.98%,and mixed infection for 2.96%. Klebsiella pneumoniae and P. aeruginosa were the more common bacteria in adults and seniors than in children,while streptococcus pneumoniae was more common in children. Imipenem showed the best activity against most Gram-negative bacteria,followed by cefotaxime and ceftazidime. The most susceptible antibiotic for Gram-positive bacteria was vancomycin,followed by rifampin. Almost all Gram-negative bacteria showed resistant to ampicillin and most of Gram-positive bacteria were resistant to penicillin and oxacillin. Conclusion:Gram-negative bacteria are the most common pathogenic organisms in LRTI in this study. But the proportion of pathogenic agents is different among different age groups. The antibiotics resistance is severe. So bacterial culture of sputum should be examined before initiating antibiotics treatment for LRTI.