| Background and ObjectivesAcinetobacter baumannii(Ab)is a non-fermenting Gram-negative bacillus widely distributed in nature and hospital environments and is a conditional pathogen.It often leads to pneumonia,bacteremia,urinary tract infections,central nervous system infections and wound infections,and has now developed into one of the common pathogens in hospitals and communities.According to the National Bacterial Resistance Surveillance Network of the Ministry of Health,the clinical isolation rate and drug resistance rate of Acinetobacter baumannii are increasing,and multi-drug resistant,pan-resistant and fully resistant Acinetobacter baumannii are spread around the world.Outbreaks have caused great difficulties in clinical treatment.Neurosurgery has gathered a large number of critically ill patients,patients with severe illness,long-term coma leading to long bed rest,often combined with a variety of invasive operations,providing an opportunity for invasion of Acinetobacter baumannii colonized in the environment.There are reports at home and abroad that all kinds of instruments,bed units and hands of medical staff who are often touched in the intensive care unit's diagnosis and treatment activities have detected Acinetobacter baumannii,which may be one of the important causes of cross infection in hospitals.Collect molecular and epidemiological investigations of strains isolated from environmental and clinical patients,analyze whether there is homology between the two strains,and understand the main epidemic clones of Acinetobacter baumannii in this period,which can provide control for nosocomial infections.Theoretical basis.At present,the domestic resistance mechanism of Acinetobacter baumannii is mainly the production of oxacillin and metallactamase.However,due to the complex drug resistance mechanism of Acinetobacter baumannii,the drug resistance of different drugs in different regions,There may be differences in the mechanism of drug resistance,and the drug resistance genes carried by Acinetobacter baumannii were detected to investigate the distribution of drug-resistant genes related to carbapenem-resistant Acinetobacter baumannii and possible modes of transmission.Methods1.From January to December 2017,62 cases of Acinetobacter baumannii in neurosurgery in our hospital were selected.A case-control study was conducted to select 174 cases of non-B.aurella infection in the same period as the control group.Clinical data were collected,and risk factors for infection with Acinetobacter baumannii were analyzed by univariate analysis and multivariate logistic regression.2,from January 2018 to October 2018,the collection of Acinetobacter baumannii in the neurosurgical intensive care unit,as well as Acinetobacter baumannii isolated from clinical patients in the same period,using MLST gene scores for two sources of Acinetobacter baumannii Type,and use the eBURST software to compare the obtained ST type with the database for homology analysis.3.The minimum inhibitory concentration of clinically used antibacterial drugs against clinical strains and environmental strains was determined by agar dilution method.The carbapenem-resistant strains were selected for PCR amplification to detect the drug resistance genes they carried.4.In January 2018,strict infection control measures were implemented for neurosurgery,and the changes in bacterial resistance rate before and after the sensory control measures were compared.The main results:1.Univariate analysis found that the risk factors for neurosurgical infection of Acinetobacter baumannii include: age,hospitalization time before infection ?14d,ICU time before infection,?7d,GSC score ?8,APACHEII score ?20,four generations before infection Use of cephalosporins,?-lactams plus enzyme inhibitors,carbapenems,tigecycline,mechanical ventilation,and indwelling gastric tubes.Multivariate regression analysis showed that ICU time before infection was ?7d(OR=4.179,95%CI=1.638-10.662),APACHEII score ?20(OR=5.798,95%CI=1.695-19.829),mechanical ventilation(OR =3.726,95%CI=1.571-8.840)and the use of pre-infection ?-lactam enzyme inhibitors(OR=3.709,95% CI=1.353-10.168)for the independence of Acinetobacter baumannii infection in neurosurgical patients Risk factors.2.190 air samples were collected from the ward of the neurosurgical intensive care unit,and 300 environmental samples were collected.A total of 41 Acinetobacter baumannii were collected in the identified environment,and 63 clinical patients were collected.The detection rate of Acinetobacter baumannii in the environment was 8.4%,and the detection rate of door handle and door handle was the highest,25.0% and 21.4% respectively.In the air,bed unit,ventilator operation panel,case card and treatment cart,medical staff clothing or hand,ECG monitor,suction tube also detected Acinetobacter baumannii,the detection rate was 10.5%,8.9%,8.3%,7.7%,5.6%,5.0% and 4.5%.3,104 strains of Acinetobacter baumannii were divided into 27 ST types.The ward environmental strains were mainly ST2(41.5%,17/41),ST40(12.2%,5/41)and ST132(9.8%,4/41);the clinical patient specimens were ST2(52.4%,33/).63),ST40(7.9%,5/63),ST57(4.8%,3/63),ST768(4.8%,3/63)and ST877(4.8%,3/63).Using eBURST software,65 strains of ST2,ST40,ST143,ST195,ST520 and ST1278 belong to CC2 and have homology.4.The resistance rate of environmentally isolated strains was lower than that of clinical isolates,and there were statistical differences between the two groups.Acinetobacter baumannii derived from clinical and environmental isolation is sensitive to polymyxin B and tigecycline,but the resistance rate of clinical isolates to ceftazidime,cefepime and piperacillin tazobactam is greater than 50.%,also resistant to imipenem,meropenem and cefoperazone sulbactam,the resistance rates were 49.2%(31/63),49.2%(31/63),42.9%(27/63).Environmental strains are <50% resistant to commonly used drugs;for ceftazidime,cefepime,piperacillin tazobactam,imipenem,meropenem,cefoperazone sulbactam,amikacin And levofloxacin resistance rates were 36.6%(15/41),36.6%(15/41),31.7%(13/41),29.9%(12/41),29.9%(12/41),19.5%,respectively.(8/41),7.3%(3/41),4.9%(2/41).5.Before and after infection control,the resistance rate of Acinetobacter baumannii to clinically used antibiotics decreased slightly,but the difference was not statistically significant.6.To detect the resistance genes of 43 strains of carbapenem-resistant Acinetobacter baumannii,31 clinical patients,and 12 strains from the environment.The results showed that OXA-51 was all positive,42 strains of OXA-23 were positive,2 The strain was positive for OXA-58,and 2 of them carried the three drug resistance genes simultaneously,which were derived from environmental strains.KPC,NDM,VIM,IMP,GES,OXA-24 and OXA-48 resistance genes were not detected.Conclusions1.There are many risk factors for infection of Acinetobacter baumannii in neurosurgical patients.Strict operation should be strictly carried out in the course of treatment and nursing,grasp the indications of invasive treatment,rational use of antibiotics,and timely turnover of ICU patients.2.There are many types of Acinetobacter baumannii in the neurosurgical intensive care unit of our hospital,but the ward environment and the clinical isolates of the patients are all in the proportion of ST2 and ST40.The bed unit,door handle,door handle and air in the environment.There are pollution of Acinetobacter baumannii,and they belong to the same type,and there is a possibility of cross infection.3.The resistance rates of environmentally isolated strains and clinical isolates were significantly different,but the ?-lactamases carried by Acinetobacter baumannii were mainly OXA-23 and OXA-51.There was no difference between the two groups,and further detection of variable regions is still needed. |
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