Resistance Of Bacteria And Molecular Epidemiology Of Carbapenem-resistant Enterobacteriaceae

Objective:To investigate the distribution and drug resistance of clinical bacteria in the Second Affiliated Hospital of Kunming Medical University, and the molecular epidemiology of carbapenem-resistant Enterobacteriaceae, provide the basis for the control and treatment of bacterial infections.Methods:1.The distribution and drug resistance of the clinical bacteria infection were retrospectively analyzed in the Second Affiliated Hospital of Kunming Medical University in 2013. Using VITEK-2 Compact bacterial identification system identification, disc diffusion test(K-B method)was used to study the antimicrobial resistance.Results were interpreted according to the breakpoints of CLSI 2013.WHONET 5.6 was applied for analysis.2.77 strains (excluding repetitive strain) isolated carbapenem-resistant Enterobacteriaceae were collected in the Second Affiliated Hospital of Kunming Medical University from September 2012 to December 2013. The phenotype of carbapenemase was selected by Modified Hodge test and EDTA double-disk synergy test.The resistance genes were detected by polymerase chain reaction (PCR).The carbapenem-resistant Klebsiella pneumonia were performed homology analysis by pulsed-field gel electrophoresis (PFGE).Results:1.The main source of these pathogens were urine, sputum, blood, secretions and pus, respectively 31.7%,21.4%,19.7%,11.7%,7%.In the separation of the 4350 strains of bacteria, gram negative bacilli accounted for 61.6%, gram positive cocci accounted for 35%, fungi accounted for 3.4%. In gram negative bacilli, high rate of separation were Escherichia coli (29.1%), Klebsiella pneumoniae (9.9%), Pseudomonas aeruginosa (8.5%) and Acinetobacter baumannii (4.5%). In gram positive cocci, high rate of separation were coagulase negative staphylococcus (16.6%), Enterococcus (10.4%), Staphylococcus aureus (6.1%). The majority of fungi was Candida albicans.1970 strains of Enterobacteriaceae bacteria, Escherichia coli accounted for 64.2%(1264 strains), Klebsiella pneumonia accounted for 21.8%(430 strains), Enterobacter cloacae accounted for 6.9%(136). Enterobacteriaceae is most sensitive to carbapenem, resistance rate less than 10%. Escherichia coli and Klebsiella pneumoniae producing ESBLs detection rate respectively is 61.1%,49.1%.Non fermentative gram negative bacilli, except for Pseudomonas aeruginosa has good sensitivity to Amikacin, Pseudomonas aeruginosa and Acinetobacter baumannii showed a great resistance to most antibiotics (> 30%). In gram positive bacteria, MRSA and MRCNS detection rate were 42.3% and 65.6%. Most of the antibiotic resistance of Enterococcus faecium was higher, in addition to linezolid and teicoplanin, Enterococcus faecium were higher antimicrobial resistance rate than Enterococcus faecalis, detected a strain Enterococcus faecium resistant to vancomycin.2.77 isolates of carbapenem resistant Enterobacteriaceae,55 isolates were positive in Modified Hodge test, of which 53 Klebsiella pneumoniae,1 Enterobacter cloacae and 1 Klebsiella oxytoca.15 isolates were positive in EDTA double-disk synergy test. PCR amplification results showed that 45 isolates produced KPC type carbapenemase,9 isolates produced NDM-1 type carbapenemase,5 isolates produced IMP type carbapenemase,18 isolates with no amplification of specific strip. When 52 strains of carbapenem-resistant Klebsiella pneumonia were homology analyzed by PFGE, the results are divided into 4 types, type A 22 strains,18 strains of type B, type C 9 strains,4 strains of type D.Conclusion:The drug resistance situation is severe in the Second Affiliated Hospital of Kunming Medical University, the rate of bacterial drug resistance monitoring should be strengthened in hospital, to guide the clinical rational use of antimicrobial agents. PCR amplification results showed that 45 isolates produced KPC type carbapenemase,9 isolates produced NDM-1 type carbapenemase,5 isolates produced IMP type carbapenemase, and 18 isolates with no amplification of specific strip in 77 isolates of carbapenem resistant Enterobacteriaceae. There may be other resistance mechanisms such as target change, efflux pump expression, remains to be studied further.52 strains of carbapenem-resistant Klebsiella pneumonia of PFGE homology analysis revealed 4 types, indicate that the carbapenem-resistant Klebsiella pneumonia of different clones were popular in the Second Affiliated Hospital of Kunming Medical University, and A.B strains was clonal transmission,the hospital infection department and clinical departments should take measures to control the spread of these strains in the hospital.