| Antimicrobial agents are the most widely used class of drugs in clinical practice therapy,and which play a pivotal role. But the abuse of antibiotics has caused the emergence of antimicrobial resistance in a wide range and the prevalence of infections caused by drug-resistant pathogens. Antimicrobial resistance has become the world's attention problems. Bacterial resistance surveillance is needed to guide rational use of Antimicrobial agents,and that is a powerful weapon to solve this global problem. Many Countries are performing studies of bacterial resistance surveillance on different scales. A number of bacterial resistance monitoring networks have been established, there are Mohnarin, CHINET, SEANIR and other monitoring networks in China.At different periods, conditions of antimicrobial resistance are quite different. The occurrence and development of bacterial resistance are affected by a variety of factors, especially the pressure of antimicrobial agents. These factors cause,even at the same period,the variation of drug resistance rate of the same kind of bacteria which are from different countries, different regions, different hospitals and even differentl wards. Therefore, the results of antimicrobial resistance monitoring in specific departments possess a proper reference value for practical clinical application. Based on the data steming from the consecutive, long-term monitoring, we can investigate the species, distribution and drug resistance of pathogenic bacteria, sum up the drug resistant patterns of the major pathogenic bacteria in specific departments, grasp real-time accurate information on the trend of bacterial resistance, and find out the change of drug resistant bacteria, which have important significance for guiding the clinical rational use of antibiotics, reducing drug-resistant strains, effectively controlling of hospital infection and reducing the mortality. In order to investigate the distribution characteristic and drug resistant profile of clinical isolates in our hospital,and to guide the rational use of antimicrobial agents, so the results of antimicrobial susceptibility testing of clinical isolates were analyzed. From January 2007 to December 2009,2784 consecutive and non-repetitive cocci were collected, which were identified by API system combining with manual methods. Antimicrobial susceptibility testing were detected by disk diffusion test. According to CLSI guidelines on drug susceptibility testing, and the clinical practice of our hospital, the appropriate antimicrobial agents groupings were selected for the specific organism groups. MecA-mediated oxacillin resistance in staphylococcus, and extended spectrumβ-lactamase production in enterobacteriaceae were screened. According to the updated standard of CLSI, the results of antimicrobial susceptibility testing were reported. In accordance with the request of WHONET, the monitoring data were logged and the results were analyzed by WHONET5.3 software.The results showed that in our hospital gram-negative bacteria were the major portion, accounting for 3/4, of which the incidence of nonfermentative bacilli was a little higher than that of enterobacteriaceae. The most common isolated pathogens were Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, coagulase-negative staphylococci, S. aureus, E. coli, Enterobacter cloacae, Stenotrophomonas maltophilia, enterococci, etc. Specimens were relatively concentrated in respiratory medical wards and ICU. In different departments, the distrubution of kinds of pathogens was quite different. Enterobacteriaceae were the most frequently isolated pathogens in medical wards. The most common pathogens were nonfermentative bacilli in ICU, and yet gram-positive bacteria in surgical wards. The most quantity of pathogenic strains originated from sputum samples, followed by urine samples, blood samples, secretion samples, drainage fluid samples and so on. The distribution of samples indicated that respiratory system infections occupied an important position in the infectious diseases in our hospital. The distribution of bacteria in different samples were also quite different. In sputum samples, the most common pathogens were acinetobacter baumannii, klebsiella pneumoniae and Pseudomonas aeruginosa,, in urine specimens, the most common pathogens were E. coli, enterococci and proteus, in blood samples, the most common pathogens were coagulase-negative staphylococci, E. coli and S. aureus, in secretion samples, the most common were coagulase-negative staphylococci, S. aureus and E. coli.The analysis of the surveillance indicated that drug-resistance of Staphylococcus in our hospital was quite a big problem. The prevalence of MRSA and MRSCN was 8.1%and 91.6%, respective, and was significantly higher than the national average. Staphylococcal Isolates showed a high prevalence to gentamicin, ciprofloxacin and erythromycin. No Staphylococcal isolates were found resistant to vancomycin. Isolates of Enterococci were highly susceptible to vancomycin, only two vancomycin-resistant enterococci strains were found in this study, and yet highly resistant to high level aminoglycoside and ciprofloxacin. The most common Enterobacteriaceae were Klebsiella pneumoniae, E. coli, enterobacter cloacae and so on. The prevalence of extended spectrum beta-lactamases-producing klebsiella pneumoniae and E. coli was 23.9%and 44.7%, respectively. More than 30%of Enterobacteriaceae were resistant to the third-generation cephalosporin. Ceftazidime resistance rates was less than that of other third-generation cephalosporins. The antibacterial activity of cefepime to Enterobacter bacteria was significantly better than the third-generation cephalosporins, and yet equal to ceftazidime to other Enterobacteriaceae. Isolates of Enterobacteriaceae showed a high susceptible prevalence to carbapenem, the average resistant rate was 0.7%.β-lactam/β-lactamase inhibitor combinations showed a better antibacterial activity to Enterobacteriaceae in comparison with relevant unilateral agent. More than 70%of E. coli strains were resistant to ciprofloxacin, and other Enterobacteriaceae were relatively sensitive to ciprofloxacin. Producting AmpC in high-yielding is the main resistance mechanism for Enterobacter cloacae, which were highly resistant to cefoxitin. In nonfermentative bacilli, acinetobacter baumannii, pseudomonas aeruginosa, stenotrophomonas maltophilia were more common. The incidence of multidrug-resistant pseudomonas aeruginosa and acinetobacter was 8%and 45.1%, respectively. Isolates of nonfermentative bacilli were relatively highly resistant to the carbapenem. Up to 20%strains of acinetobacter baumannii and pseudomonas aeruginosa were resistant to imipenem. Isolates of stenotrophomonas maltophilia showed a high susceptible prevalence to levofloxacin, trimethoprim-sulfamethoxazole and minocycline. In ICU and non-ICU wards several important pathogens showed a significant difference in the isolated rates and resistant rates. Isolates of MRSA, ESBLs Producing klebsiella pneumoniae and E. coli, imipenem-resistant pseudomonas aeruginosa and acinetobacter baumannii in ICU were more than that in non-ICU wards.The results of the study showed that antimicrobial resistance of clinical isolates was a serious problem in our hospital, resistance rates increased significantly; pathogents were resistant to a variety of antimicrobial agents,and were highly sensitive to rarely agents; in ICU and non-ICU wards isolated rates of several major resistant pathogents had significant difference; Based on the results of bacterial resistance surveillance, we can find whether strains possessing similar drug-resistant spectral characteristics are prevalent, thereby we can effectively control the transmission of resistant bacteria; we should establish bacterial resistance surveillance and early warning mechanisms in the special wards and the hospital, and take appropriate intervention measures, which has important practical significance for guiding clinical use of drugs and controlling nosocomial infection.
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