Dynamic Analysis On Bacterium Spectrum And Drug Resistance Of Lower Respiratory Tract Infections For Consecutive 5 Years

Objective: To investigate the bacterial spectrum of lower respiratory tract and the drug resistance change as well as its trend in our hospital for consecutive 5 years in order to provide basis for the reasonable use of antibiotics in clinic.Methods: Bacteria strains cultured from sputum specimens of inpatients in the first affialiated hospital in Anhui medical university from June 2009 to December 2013 were collected. All the data were input WHONET 5.6 and statistically analyzed by SPSS17.0.A p-value <0.05 was considered significant in all statistical analyses.Results: 6564 bacteria strains were isolated with bacteria from 37,410 sputum spectimens from lower respiratory tract, including gram-positive bacteria 617(9.4%)and gram-negative bacteria 5947(90.6%). The most common detected bacteria was Acinetobacter baumannii(22.2%), followed by Pseudomonas aeruginosa(19.9%),Klebsiella pneumoniae(15.3%), Staphylococcus aureus(7.6%), Escherichia coli(7.5%),Stenotrophonwnas maltophilia(6.2%) and Enterobacter cloacae(5.2%).Methods the five years cases of bacteria detection rate by Chi-square and trend Chi-square tests, find Acinetobacter baumannii and Pseudomonas aeruginosa were in an in an increasing tendency.Compared 2013 with 2009, the detection rate of gram-negative bacteria increased obviously(P<0.05). However, there was no difference in the detection of gram-positive bacteria(P> 0.05).The resistance rate of Acinetobacter baumannii against minocylin was the lowest(15.8%~37.1%), followed by cefoperazone and sulbactam(23%~30.8%). However, the resistance rates against other anti-biotics were about 40% or higher, especially againstceftriaxone. The resistance rates of pseudomonas aeruginosa against amikacin and the fourth generation cephalosporins were about 20% or lower while the resistance of pseudomonas aeruginosa against cefotaxime was more than 80%. Ampicillin resistant strains account for more than 88% of Escherichia coli and Klebsiella pneumoniae whileβ- lactamase inhibitor compound resistant strains were barely found. Ampicillin resistant strains account for more than 94% of Enterobacter cloacae. However, the resistance rate of cefoperazone sulbactam and piperacillin tazobactam of Enterobacter cloacae account for 25% or lower respectively. Maltophilia Aeromonas strains isolated were resistant to most of antibiotics including imipenem. But levofloxacin, minocycline and cotrimoxazole recommended by CISI M100-S23 resistant strains accounted for30% or lower. Staphylococcus ureus were resistant to many kinds of anti-biotics,however no vancomycin and teicoplanin resistant strains was found yet.Conclusion:During these five years, the most common strains isolated from lower respiratory tract in our hospital was gram-negative bacilli and most of them were opportunistic pathogens with high drug resistant rate,also find Acinetobacter baumannii and Pseudomonas aeruginosa were in an increasing tendency. The resistant rate was in an increasing tendency since 2009 to 2012 and decreased in 2013. The detection rate of gram-positive bacteria remained 8% during the 5 years.The most common isolated strain was Staphylococcus aureus. The gentamicin resistance rate was in an increasing tendency while resistance rate against other drugs didn’t have a significant change. The high resistant rate in bacteria in our hospital has brought great challenge to clinical treatment, which need attachment of great importance to drug sensitivity test and the rational use of antibiotics.