Analysis Of Gram-negative Bacilli Distribution And Antibiotic Resistance In Intensive Care Unit Patients With Lower Respiratory Tract Infection

ObjectiveTo investigate the distributive characteristics and antimicrobial resistances tendency of Gram-negative bacilli isolated from patients with lower respiratory infection in intensive care unit from 2004 to 2007,and provide valuable data and reasonable selections for antibiotic in clinical treatment.Methods1.A total of 1561 sputum strains isolated from ICU inpatients with lower airways infections during 2004 to 2007 were analyzed for the drug susceptibility of pathogens.2.Bacterial susceptibility and ESBLs test was carried out by Kirby-Bauer method according to NCCLS standards.3.Data were analyzed by using a statistical software program(SPSS for Windows,version 13.0,SPSS Inc),chi-square or Fisher Exact test were used for analyzing the drug resistance of pathogenic bacteria.Results1.The distributive characteristics of pathogens:1352 strains of Gram-negative bacilli were isolated,accounted for 75.2%of total strains,and the isolating rate was raised year by year.The most predominant pathogens were Pseudornonas aeruginosa(42.7%), Acinetobacter baumannii(16.3%),Strenotrophomonas maltophilia(10.4%), Escherichia coli(10.0%),and Klebsiella pneumoniae(6.7%).Pseudomonas aeruginosa was fluctuating at a high level(about 40%).The detection out ratio for Escherichia coli and Klebsiella pneumoniae had gradually increased.In the primary isolated bacteria,the most predominant pathogens were Pseudomonas aeruginosa(32.1%),Acinetobacter baumannii(17.9%),Escherichia coli(12.7%),Strenotrophomonas maltophilia(11.2%),and Klebsiella pneumoniae (6.2%).Pseudomonas aeruginosa was still the most major pathogen.The detection out ratio for Escherichia coli and Acinetobacter baumannii had gradually increased but the detection out ratio for Strenotrophomonas maltophilia had decreased.2.The detection out ratio for ESBLs producing Enterobacteriaceae was 52.1%. ESBLs producing strains were detected in 65.9%of Escherichia coli and 52.7%of Klebsiella pneumoniae strains,and had gradually increased during 2004 to 2006.3.The drug susceptibility of Enterobacteriaceae3.1 Carbopenems remained highly active against to Enterobacteriaceae bacterial, and so as cefoperazone/sulbactam.The drug resistance rates to the third and forth generation cephalosporin between ESBLs non-producing strains and ESBLs producing strains were 6.5%～31.3%Vs 35.7%～95.5%,while the rates of aminoglycosides and quinolones were 15.2%～78.3%Vs 33.7%～94.4%.3.2 The drug susceptibility of Escherichia coli:the resistance rates of ESBLs producing Escherichia coli to carbopenems and cefoperazone/sulbactam were 4.5% and 11.2%,but to most cephalosporin were 89.9%,to other antibacterial agents were high(70.8%～94.4%).The resistance rates of ESBLs non-producing Escherichia coli to the third and forth generation cephalosporin and cefoperazone/sulbactam were low (2.2%～28.3%),and the sensitivity of which to carbopenems were entire.The drug resistance rates to ceftazidime and cefepime had gradually decreased.3.3 The drug susceptibility of Klebsiella pneumoniae:the resistance rates of ESBLs producing Klebsiella pneumoniae to cefepime and cefoperazone/sulbactam were 41.7%and 31.3%,and to carbopenems was low(＜4.2%),but to most other antibacterial agents were high(56.3%～91.7%).The drug resistance rate to aminoglycosides had gradually decreased.The resistance rates of ESBLs non-producing Escherichia coli to the third and forth generation cephalosporin, amikacin and cefoperazone/sulbactam were low(2.3%～25.6%),and the sensitivity of which to carbopenems were entire.4.The drug susceptibility of Nonfermentative gram-negative bacilli4.1 The drug resistance rates of Acinetobacter baumannii to most antibacterials were high(64.9%～99.4%),to imipenem,Meropenem and cefoperazone/sulbactam were 26.6%,32.9%and 11.2%.Compared with the primary isolated Acinetobacter baumannii,the drug resistance rates of total Acinetobacter baumannii to ceftazidime, cefepime,Meropenem and cefoperazone/sulbactam were more than 10%～15%.4.2 The drug resistance rates of Pseudomonas aeruginosa to ceftazidime,cefepime were about 50%,to imipenem,Meropenem and cefoperazone/sulbactam were 48.6%,54.5%and 44.2%.But the drug resistance rates to ceftazidime,cefepime and cefoperazone/sulbactam had gradually decreased. Compared with primary isolated Pseudomonas aeruginosa,the drug resistance rates of total Pseudomonas aeruginosa to the third and forth generation cephalosporin, carbopenems and Ofloxacin were higher.4.3 The drug resistance rates of Strenotrophomonas maltophilia to SMZ-TMP and quinolones were 32.6%and 43.2%,but to most cephalosporin and aminoglycosides were serious.Compared with the primary isolated Strenotrophomonas maltophilia,the drug resistance rates of total Strenotrophomonas maltophilia to quinolones and cefoperazone/sulbactam were more than 10%.Conclusions1.Pathogens of patients with lower respirator(?)infection in ICU are mainly Gram-negative bacilli;most of them are multidrug-resistance and conditional bacterial pathogens.2.The detection out ratios for ESBLs producing Enterobacteriaceae were high, and the drug resistance rates of ESBLs producing pathogens to most antibacterials were serious.The drug resistance rates between ESBLs pruducing and ESBLs non-producing Enterobacteriaceae were obviously differente.3.The drug resistance rates of Nonfermentative gram-negative bacilli were serious.It is essential to pay more attention to the continuous surveillance of antimicrobial resistance in clinics in order to select antibiotics rationally.4.It is important to investigate the distribution and antimicrobial resistances tendency of primary pathogenic bacteria in order to select early treatment rationally.