Epidemiological Investigation Of A. Baumannii Clinical Infection And The Detection Of Drug-resistant Genes From Their Nosocomial Infection Strains

Objective To investigate the epidemiological characteration and drug resistence of the clinial infection by acinetobacter baumannii in Rizhao People's Hospital.To detect the gene existance ofβ-lactamase(BLA) and aminoglycoside-modifying enzymes(AMEs) in the stains causing nosocomial infection.Methods Acinetobacter baumannii were isolated and identified from the clinical specimens by Phoenix-100 automatic bacteria appraiser.The characterations of their epidemiology including the sources of specimens and division of the cases,types of infection were investigated.Their sensitivity to currently used 16 antibiotics were detected with the methodd of microdilution.4β-lactamases genes were amplified by nest-PCR(TEM,SHV)and routine PCR(AmpC DHA,AmpC MIR)respectivily in 30 selected strains causing nosocomial infection and 4 genes of aminoglycoside-modifying enzymes(aac(3)-Ⅰ,aac(3)-Ⅱ,aac(6)'-Ⅰ,ant(3')'-Ⅰ)were amplified by PCR in 8 strians as well.Further,the correlation between the existence of detectedβ-lactamases genes and resistanance toβ-lactam antibiotics was presumed rudimently.Results 121 strains of acinetobacter baumanni were identified.Their infection took place widely,nosocomial pneumonia was mostly found and the cases were potencially gathered in ICU.The results of drug sansitivity showed that the percentage of drug resistence increased continiously year by year.The rate of resistence to ATM was as high as 90.1%.The resistence to CTX,GM,CAZ,FEP,CRO and PIP was over 79%.86 strains were resistent to more than 5 antibiotics.While,the sansitivity to 2 kinds of carbopenems antibiaotics was about 90%.The detection of resistence genes proved that the positive percentage in 4β-lactamases genes were TEM 76.7%,SHV 10.0%,AmpC DHA 33.3%, AmpC MIR 30.0%,respectively.Conclusion The most strains of acinetobacters baunannii isolated from our hospital were those causing nosocomial infection.The resistant stage to currentally used antibiaotics was serious and the strains of high resistance and multi-resistance were widely existance.The key resaeson of resistsnce toβ-lactam antibiotics in those acinetobacter baumannii was the existance of theβ-lactamases genes.