Analysis Of The Bacterial Strains And Antibiotic Sensitivity Of 264 Positive Blood Cultivations

Objective: To analyze the bacterial strains and antibiotic sensitivity of positive blood cultivation in order to provide a theory reference for clinical antibiotic use.Methods:Clinic data of 253 patients, whose 264 blood bacterial cultivations were positive in the First Affiliated Hospital of Soochow University during January 2007 to December 2009, were collected from their electronic medical records. The age, sex, clinical department,underlying diseases, bacterial strains , antibiotic sensitivity of those patients were analyzed. Antibiotic sensitivity was detected with Kirby-Bauer method. SPSS16.0 software used in statistical analysis.Results:Gram-positive bacteria and Gram-negative bacteria was 39.02% and 60.98% respectively in the total of 264 positive blood cultivations. The top three species of Gram-positive bacteria were Staphylococcus aureus 9.85% (26 strains), Staphylococcus epidermidis 9.09%(24 strains) and Staphylococcus haemolyticus 4.17% (11 strains), and that of Gram-negative bacteria were Escherichia coli 26.89% (71 strains), Pseudomonas aeruginosa 9.47%(25 strains) and Klebsiella pneumoniae bacteria 7.95%(21 strains).Methicillin-resistant Staphylococcus (MRS) accounted 58.1% (36 strains) for staphylococci. 19.4% (7 strains) of MRS was methicillin-resistant Staphylococcus aureus (MRSA) which was increasing in the past three years (P<0.05), and 80.6% (29 strains) was methicillin resistant coagulase negative Staphylococcus. Methicillin-resistant Staphylococcus kept 100% sensitive to vancomycin and teicoplanin, and a good sensitivity to rifampin, poor to other antibiotics. 2 strains of E. faecalis were resistance to vancomycin and teicoplanin. The proportion of producing extended spectrumβ-lactamases (ESBLs) in Escherichia coli and Klebsiella pneumoniae was 67.6% and 42.8% respectively. In the past three years, the rate of Klebsiella pneumoniae producing extended spectrumβ-lactamases was rising, but there was no significant difference (P> 0.05); Escherichia coli and Klebsiella pneumoniae kept 97% and 90.5% sensitivity to imipenem respectively. 84% of Pseudomonas aeruginosa was sensitive to imipenem, which also showed a good sensitive to other common antibiotics. 7 strains of Acinetobacter baumannii were multi-drug resistant strains, only 57.1% sensitive to imipenem, and 2 of 7 strains presented the Pan-resistant properties. 4 strains of Xanthomonas maltophilia were all multi-drug resistant strains.Conclusion:Gram-negative bacterias are the main strains in the positive blood cultivation. Staphylococcus is the main strain of gram-positive bacterias. Methicillin-resistant Staphylococcus accounted a high proportion for Staphylococcus.Methicillin-resistant Staphylococcus aureus is increasing recently years. Staphylococci is fully sensitive to vancomycin and teicoplanin. Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae are the main strains of gram-negative bacteria. The rate of producing extended spectrumβ-lactamase strains in Escherichia coli and Klebsiella pneumoniae is high. The majority of Gram-negative bacterias keep sensitive to imipenem. Strengthening monitoring, analyzing of the bacterial strains and drug resistance of blood cultivation can provide a good reference to clinic rational using of antibiotic.