Abstract: Abstract:Objective To observe the antimicrobial effect of a kind of Chinese medicine Qingre compound preparation on the common pathogenic bacteria of upper respiratory tract infection (URTI). Methods A total of 163 common pathogen⁃ ic bacteria of URTI was selected in this study, including 74 non extended-spectrum β- lactamases (ESBLs)-producing Gram-negative bacteria (33 Escherichia coli, 24 Klebsiella pneumonia and 17 Pseudomonas aeruginosa), 10 ESBLs-produc⁃ ing Gram-negative bacteria (6 Escherichia coli and 4 Klebsiella pneumoniae) and 79 Gram-positive bacteria [11 methicil⁃ lin-resistant Staphylococcus aureus (MRSA), 46 methicillin-sensitive Staphylococcus aureus and 22 Streptococcus pneu⁃ moniae]. Agar dilution method was adopted to perform the quantitative drug sensibility test. Agar plates that contained differ⁃ ent concentrations of Qingre compound preparation were prepared. The bacterial suspension was planted on the plates. Then we observed the plates after incubation, and recorded the minimum inhibitory concentration (MIC). Results The antimicro⁃ bial rates of Qingre compound preparation were 88, 176 and 22 g/L for MIC90 of Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. The antimicrobial effects of Qingre compound preparation were coincident on the MIC90 of ES⁃ BLs-producing strains and non ESBLs-producing strains. The accumulated antibacterial rates of different concentrations of medicine to Pseudomonas aeruginosa were the highest. The MIC90 values of Qingre compound preparation were 11, 11 and 22 g/L for MSSA, MRSA and Streptococcus pneumoniae. The MIC90 of MRSA was coincident with MSSA, but MIC50 of MRSA was slightly higher than that of MSSA. The accumulated antibacterial rates of different concentrations of medicine to MSSA and MRSA were all higher than those of Streptococcus pneumonia. The accumulated antibacterial rate of MSSA was similar with that of MRSA. Conclusion The Chinese medicine Qingre compound preparation could restrain common patho⁃ genic bacteria of URTI except Klebsiella pneumoniae. The antibacterial effect of Qingre compound preparation is significant⁃ ly better in Ggram-positive bacteria than that of Gram-negative bacteria.

Key words: respiratory tract infections, microbial sensitivity tests, Gram-negative bacteria, Gram-positive bacteria, pathogenic bacteria, agar dilution method, qingre compound preparation