Analysis Of Risk Factors And Investigation Of Bacterial Flora Characteristics Of Chronic Wounds On Adult Body Surface

BackgroundChronic Refractory Wounds(CRW)would be a major clinical and public health problem that aging society must confront.The risk factors of CRW were diverse and changed with the alterations of people’s lifestyle and chronic disease spectrum.Presently,research on risk factors of CRW in China were few and mainly cross-section study,lacking in case control studies.The data and investigation content were limitedly from hospital information system.In addition,microbiome load had been recognized as an important factor affecting wound healing.On one hand,patients with CRW tended to be older and had underlying medical conditions.Their immune function was inhibited,resulting in susceptibility to wound infection and delay healing.On the other hand,skin microbiome disorder might also play a role in CRW.It was necessary to explore the characteristics of microflora in CRW and peri-wound skin.However,few studies had been conducted on it.In this study,patients with CRW were taken into a case-control study.Normal healing wounds were taken as controls.Medical records,living habits and other factors were included in the investigation to analyze the risk factors of CRW more comprehensively.To clarify the microflora characteristics of CRW,16 s r DNA sequencing analysis was performed on wound and peri-wound skin swab samples of patients with CRW and control.Our research would contribute to a more comprehensive understanding of the risk factors and microbiological pathogenesis of CRW,and would provide a basis for better guide about CRW prevention and public health decisions-making.Objectives1.To analyze the risk factors of CRW,so as to provide a basis for CRW prevention,patient education and public health decision-making.2.To analyze the characteristics of microflora in CRW and surrounding skin.So as to comprehensively understand the etiological features and microbiological mechanism of CRW.3.To explore the possible correlation between the risk factors of CRW and wound or skin microbiome.MethodsPart I.Analysis of risk factors of CRW.Researchers conducted a case-control study,including 203 patients of skin wounds admitted to the Department of Burns and Plastic Surgery of Second Affiliated Hospital of Air Force Military Medical University from January 2021 to May 2022.Patients aged under 18,diagnosed with a psychiatric disorder,and did not wish to join the study were excluded.All subjects were classified into chronic wounds group and control group according to the criteria of whether the wound healed or showed a tendency to heal within one month.Questionnaire survey and medical records were used to collect the general information,living habits and clinical data of patients.The data were screened by Logistic regression analysis to effectively analyze the independent risk factors of chronic skin wounds.Part II.Investigation of bacterial flora characteristics of CRW.The subjects were 99 patients with skin wounds admitted to the Department of Burns and Plastic Surgery of Second Affiliated Hospital of Air Force Military Medical University from January 2021 to October 2021.The inclusion and grouping criteria were same as above.Swab samples of wound and peri-wound skin were collected from subjects.By using high-throughput sequencing technology and the bioinformation analysis platform,the sequences of the V3-V4 region of the r DNA gene of the samples were analyzed to explore the overall bacterial flora characteristics and find the different species with marker significance in CRW.The study was approved by the ethics committee of the Second Affiliated Hospital of Air Force Military Medical University.ResultsPart I.Analysis of risk factors of CRW.1.A total of 100 cases of CRW and 103 cases of control were included in the study.The main wound types of CRW included postoperative non-healing wounds(27%),infectious ulcers(21%),diabetic foot ulcers(18%),scar ulcers(15%)and pressure ulcers(10%).2.Only 9% of all study participants had knowledge about the causes,harms,prevention and home care of CRW.3.The results of multivariate analysis showed that smoking cigarettes more than 10/day(P=0.016,OR =3.414,95%CI =1.260～9.253),shower every 3 days or more(P=0.027,OR =2.710,95%CI =1.394～9.731),diabetes mellitus(P=0.023,OR=4.074,95%CI =1.488～11.155),and infection(P=0.001,OR =4.074,95%CI=1.780～8.015)were independent risk factors of chronic wounds.Moderate drinking(P=0.015,OR =0.332,95%CI =0.136～0.810)and regular physical exercising(P=0.031,OR =0.431,95%CI =0.201～0.924)were protective factors of chronic wounds.Part II.Investigation of bacterial flora characteristics of CRW.1.A total of 198 samples were collected for 16 s r DNA sequencing,including 58wound/skin samples in CRW group,and 41 wound/skin samples in control group.The results of α-diversity analysis showed that bacterial flora in skin samples of control was more abundant than that in other three groups(Chao1 index,ACE index;Wilcoxon test,P≤0.001).The results of β-diversity analysis showed that the bacterial community structure of CRW,peri-CRW skin,control wound and control peri-wound skin was different(PERMANOVA,P=0.001).2.The core species of chronic wound microbiota were mainly Staphylococcus,Corynebacterium,Pseudomonas,Acinetobacter,Enterococcus,Ralstonia,Streptococcus,Escherichia/Shigella and Bacteroides.The relative abundance of Finegoldia,Prevotella,Lysinibacillus,Actinomyces and other genera in CRW samples was higher than those in control group(P<0.05).The relative abundance of Ralstonia,Herbaspirillum,Anaerococcus and other genera in the skin samples of CRW patients were lower than those in the control(P<0.05).3.Compared with normal wounds,the bacterial diversity decreased in infected wounds(Shannon index,Simpson index;Wilcoxon test,P<0.005).The relative abundance of Enterococcus was increased,but the abundance of Ralstonia and Acinetobacter were decreased in infected wound samples(P<0.05).The relative abundance of Corynebacterium and Neisseria in skin samples of the frequent bathing group(interval ≤3days)was higher than that of the interval >3 days group(P<0.05).ConclusionSmoking,low bathing frequency,diabetes and wound infection were independent risk factors of CRW.Moderate drinking and regular physical exercise could prevent chronic wounds.Health education about chronic wounds was not widely available in the population.Compared with control group,the flora richness decreased,and colonization of some opportunistic pathogens increased in both wound and skin samples of CRW.These changes might play an important role in CRW.Unfrequently bathing and infection might increase the risk of CRW by altering the microflora of the skin and wound.Bacterial diversity in infected wound decreased.Unfrequently bathing might destabilize the skin flora and lead to increased colonization of opportunistic pathogens.