Investigation Of Drug Resistance And Carbapenemase Genes In Imipenem-resistant Pseudomonas Aeruginosa And The Risk Factors For Its Infections In Xi’an

Objectives:1. To investigate the drug resistance in imipenem-resistant pseudomonas aeruginosaisolated from four triple A hospitals in Xi,an, and genotype the carbapenemase genes ofthe isolates to define the main gene types in Xi’an, in order to improve the effectiveness ofthe anti-infective empirical medication, and to know whether the isolates are eruption andepidemics.2. To collect the clinical treatment information, analyzing risk factors of IRPAinfections, in order to reduce the drug-resistant strains form, and to provide a reference forthe control of IRPA infections.Methods:1. Collecting the non-repetitive IPRA of the inpatients in four hospitals who werehospitalized from March to September in2012.2. Running drug sensitive test by K-B disc diffusion method, to analyze resistance toantibacterial drugs of IRPA. 3. Detecting carbapenemase genes by the polymerase chain reaction (PCR).4.Including in the control group, collecting clinical data, including age, gender，underlying diseases, length of stay, mechanical ventilation, use situation of antibacterialdrugs, other invasive examinations and procedures, use situation of glucocorticoids andimmunosuppressive agents, and so on, after single factor analysis then use Logisticregression analysis to analyze risk factors of IRPA infections.Results:1.In this investigation,151IRPA strains are isolated in Xi,an, among which,83isolates (55%) were from Xijing hospital,37isolates (24.5%) were from Xi,an hospital,19isolates (12.6%) were from Xibei hospital,12isolates (7.9%) were from Gaoxin hospital,and97were from male patients,54were from the females. The median age of patients was59(range21-90) and67.5%of the patients were over60years old. The shortest hospitalstay was4days and the longest hospital stay was139days. Totally strains of IRPA wereisolated from the neurosurgery ICU (37.1%), neurology ICU (27.1%)， burn unit(19.9%).Sputum was the most collected specimen (64.9%).2. Drug resistance rate of IRPA to polymyxin B can achieve0, the drug resistances tothe other9antibiotics are very high.3.94strains carried VIM gene,32strains carried IMP gene,5strains carried SPMgene,3strains carried SIM gene, GIM and NDM-1genes were all lost.4. Logistic regression analysis indicate that LOS (OR=18.774), mechanicalventilation (OR=27.365), use carbapenemase antibacterial drugs (OR=31.384) werestatistically significant (P<0.05).Conclusions:1. The infection of IRPA usually occurs in the respiratory tract and the lungs,neurosurgery ICU, neurology ICU and burn unit were the most IRPA infectiondepartments.2. The study did not find the isolates which were resistant to polymyxin B, but the presents a high resistance against multiple antibiotics to a certain degree，with obviouslymulti-drug resistance. So surveillance on drug resistance and targeted managementmeasures should be strengthened to reduce the generation and diffusion of drug-resistantbacteria.3. VIM, IMP may be the main gene types in Xi,an.4. The length of stay, early use of carbapenemase antibacterial drugs and mechanicalventilation were risk factors of IRPA infections in Xi,an.