| Acinetobacter baumannii is a non-fermentation gram-negative coccobacillus,which is widely distributed in the natural environment of water and soil,and in the hospital environment and human body skin,respiratory tract,the digestive tract and urinary tract,it is a conditional pathogenic bacteria.The bacteria can survive in the hospital environment for a long time and is one of the most common pathogens in nosocomial infection.It mainly causes respiratory tract infection,and also can cause urinary tract infection,bacteremia,surgical site infection,secondary meningitis,ventilator-associated pneumonia and so on.In recent years,antimicrobial resistance of commonly used antimicrobial agents in A.baumannii showed a trend of rapid increase,which attracts the close attention of clinical doctors and public health experts.A.baumannii could easily become multi-drug resistant A.baumannii,for which the detection rates increased quickly,posing a difficult situation for clinical treatment.Appropriate use of antimicrobial agents for targeted treatment,is of great significance for improving the clinical outcome of patients with infections.Most of current studies focused on epidemiology,transmission and surveillance of A.baumannii,while the study on the use of antimicrobial drugs in treating MDR-AB infections and its clinical significance is rare;There are some studies about the clinical outcome and influencing factors of bacteremia caused by MDR-AB,while the study on respiratory infection associated with MDR-AB and the impact of antimicrobial treatment on clinical outcome of patients was rare.To solve the above problems,the following two parts were included in this study:A.An investigation of antimicrobial resistance in clinical A.baumanniiA point-prevalence survey of healthcare-associated infection(HAI)was conducted in 2014 in a tertiary-care hospital from Beijing,the results showed that,1447 patients were investigated on the survey day,with an actual survey rate of 100.00%;87 cases of HAIs were identified,with a prevalence of 6.01%;Among the 87 HAI cases,there were 45 cases of lower respiratory tract infections,accounting for 51.72% of the total cases;Among the bacteria causing infections,the proportion of A.baumannii was 6.00%.A retrospective investigation of data on A.baumannii from the sputum,alveolar lavage fluid,blood,wound,pus,urine specimens during 2007 to 2013 in this hospital was conducted,which mainly included the detection rates of A.baumannii in different wards,as well as the change of antimicrobial resistance in A.baumannii from intensive care unit,respiratory medicine and neurology department.The results showed that most of the patients from the three departments were severe,and critically ill patients,the detection rates of A.baumannii exhibited an increasing trend from 2007 to 2013,an obvious increasing trend was observed in intensive care unit,while the rates of resistance was also increasing for A.baumannii from intensive care unit.We also found that the detection rates of A.baumannii was lower in respiratory medicine and neurology department,although the patients from these two department were also severe.It suggested that A.baumannii has become one of the most important pathogen of HAI,which should draw the attention of clinical doctors.In additional,the rates of resistance to carbapenems,cephalosporins and penicillin and other antimicrobial resistance among A.baumannii were increasing,the rates of resistance to carbapenems was above 80.00% in 2012 and 2013;The rates of resistance to fluoroquinolone and aminoglycoside was also increasing,while rates of resistance to cefoperazone /sulbactam was low.B.Analysis of antimicrobial drug use for treating respiratory tract infections caused by multi-drug resistant A.baumanniiThe use of antimicrobial drugs in treating MDR-AB in the tertiary-care hospital during 2013-2015 was analyzed.Common bacteria culture was conducted for a total of 2488 clinical respiratory specimens(sputum and lavage fluid),for the positive culture specimens of A.baumannii,pneumonia and ventilator-associated pneumonia was determined according to diagnostic criteria and cases of including and excluding criteria,as a result,702 cases of respiratory infection were included,the epidemiological data was collected.These cases were further divided into MDR-AB and non-MDR-AB group according to the results of in vitro drug sensitivity testing,the clinical outcome among these two groups was compared,and the use of antimicrobial drugs was analyzed.The clinical effect of treatment was divided into four categories,including recovery,taking effect,having progress and no effect,and was further analyzed between MDR-AB and non-MDR-AB group.For the mortality at the time of discharged from hospital,14 days and 30 days after infection,MDR-AB group was all higher than non-MDR-AB group.In 2015,the mortality at the time of discharged from hospital,14 days and 30 days after infection for MDR-AB group,were 46.22%,39.49% and 41.47%,respectively,which were higher than the mortality of non-MDR-AB group,which were 32.08%,22.64%,29.56%,respectively,their respective P values were 0.011,0.002,0.030,they were statistically different.Imipenem was the most commonly used drug in treating MDR-AB associated respiratory infections(including pneumonia and VAP),the rate of its use was as high as 47.32%;The total effective rate of antimicrobial drug use was higher in non-MDR-AB group than MDR-AB group,for the cases using carbapenems,the total effective rate in non-MDR-AB group was 74.04%,which was higher than 57.89% of MDR-AB group,the p value was low than 0.001.For the use of antimicrobial agents,we also analyzed the clinical effectiveness of monotherapy and combination therapy,the results showed that the total effective rate of combination therapy was slightly high than monotherapy,for the combinations of carbapenems and ?-lactamase inhibitor,the effective rates of in two groups were 75.00% and 80.00%,which were higher than carbapenems monotherapy(57.89% and 74.04%).Male patients accounted for 70.23% of all the respiratory tract infection cases of A.baumannii,most of the patients was 60 years or older,but there is no statistical difference in two groups.In addition,the number of patients using ventilator in the two groups was also not significantly different.To sum up,this retrospective study on antimicrobial resistance of clinical A.baumannii in a tertiary-care hospital found that the respiratory tract infection was the most common type of nosocomial infection,and the detection rates of A.baumannii increased nearly year by year;The mortality of respiratory tract infection cases for MDR-AB group was higher than non-MDR-AB group,attention should be paid for the prevention of emergence and transmission of multidrug-resistant organisms.The effective rates of combination therapy was higher than monotherapy;Risk factors analysis found that gender distribution was statistical different in two groups,while there was no significant difference in patients' age and use of ventilator.Through this study,we have deepen our understanding over the antimicrobial resistance in A.baumannii,more importantly,we have presented some useful data on the actual effectiveness of treatment of MDR-AB infections,which is important for the prevention and control of MDR-AB infections,as well as the rational use of antimicrobial drugs. |
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