Evaluation Of The Efficacy And Safety Of Polymyxin B In Elderly Patients With Pulmonary MDR-GNB Infection

Objective: To investigate the distribution of multidrug-resistant gram-negative bacteria(MDR-GNB)in elderly patients with pulmonary infection in The First Affiliated Hospital of Nanchang University,to evaluate the efficacy and safety of polymyxin B on elderly patients with pulmonary infection,and to provide evidence for its rational application.Methods: Clinical collection and retrospective analysis were performed in the First Affiliated Hospital of Nanchang University from January 1,2019 to January 31,2021,and were diagnosed with pulmonary infection.The microbial culture results were MDR-GNB cases and received polymyxin.Data of elderly patients treated for more than5 days.The gender,age,department,comorbidity,drug use,bacterial infection,clinical infection indicators,adverse reactions and prognosis of patients were recorded.According to the type of pulmonary infection,the patients were divided into three groups:HAP group,VAP group and CAP group.From pathogenic bacteria(distribution,clearance rate,factors affecting clearance)and clinical efficacy(including patient body temperature,infection indicators,symptom improvement)and safety,etc.Comprehensive analysis of its efficacy.Result:(1)A total of 179 elderly patients were included,with a male to female ratio of 2.44,an average age of 72.6±8.1 years,and an average treatment time of polymyxin B of14.7±9.8 days.(2)Distribution of pathogenic bacteria: the top five multidrug-resistant gram-negative bacteria are Acinetobacter baumannii(45.1%),Klebsiella pneumoniae(43.5%),Pseudomonas aeruginosa(5%),Onion Burkholderia(2%),Stenotrophomonas maltophilia(1%).The department rankings were respiratory and critical care medicine(35.1%),critical care medicine(31.2%),neurology(13.4%),emergency department(10%),and neurosurgery(3.9%).(3)Clinical efficacy: The body temperature of patients receiving polymyxin B treatment decreased with the prolongation of administration time.The average body temperature decreased(P<0.05).There was a statistically significant difference in the infection indexes of N% and CRP between the two groups before and after treatment(P<0.05).Taking N%=76% and CRP=9 as the cut-off points,the negative conversion rates of pneumonia after treatment were compared between the two groups.The N% and CRP of the HAP group were lower than those of the VAP group,and the difference was not statistically significant.(4)The total clinical effective rate of polymyxin B in the treatment of elderly pulmonary infection was 73.2%.The effective rate of the VAP group(72.2%)was slightly lower than that of the HAP group(76%).In the mode of administration,the effective rate of intravenous inhalation combined with aerosol inhalation and the use of double the first dose was higher than that of the patients with intravenous drip and the first dose not doubled,and there was no difference.Statistical significance;Among 83 critically ill patients,the clinical effective rate of polymyxin B for a course of more than7 days was significantly higher than that of patients with a course of less than 7 days,and the difference was statistically significant(P<0.05).(5)101 cases of MDR-GNB were cleared,and the total clinical clearance rate was56.4%.The clearance rate of VAP group(56.3%)was significantly higher than that of HAP group(34%),and the difference was statistically significant(P<0.05).Multivariate Logistic results showed that duration of polymyxin B use and combined antibiotics were independent influencing factors for the clearance of multidrug-resistant Gram-negative bacteria in elderly pulmonary infections(P<0.05).(6)The main adverse reaction of elderly patients with pulmonary MDR-GNB infection who used polymyxin B was nephrotoxicity,and the nephrotoxicity with double the first dose was higher than that in patients who did not use the first dose,but the difference was not statistically significant;A total of 20 patients(11.2%)died,mostly due to infection.Conclusion:(1)The most serious department of elderly patients infected with MDR-GNB in the First Affiliated Hospital of Nanchang University is the ICU,with MDR-AB and MDR-KP being the most common.It is necessary to strengthen monitoring and management measures in key departments,and strictly take protective measures to effectively control the MDR-GNB infection in the elderly lungs.(2)Polymyxin B has good curative effect on the elderly lung infection caused by MDR-GNB,and the improvement of VAP patients is better than that of HAP.Appropriate course of treatment can promote the improvement of pulmonary infection in the elderly.(3)The duration of polymyxin B use and combined antibiotics affect the clearance of MDR-GNB in elderly patients with pulmonary infection.