| Objectives:In order to understand the special impact of the hospital ward environment on the medical process and optimize the evaluation indicators,PM2.5,PM10,Real-time PCR,adenosine triphosphate(ATP)biofluorescence assay and microbial culture methods were performed to evaluate the complex environment of hospital wards.Subsequently,matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS)was used to identify the composition of bacteria and evaluate the microbial balence of the hospital wards.In addition,the clinical bacterial infection was analysed to assess the relationship between environmental factors and bacterial susceptibility,which provided a reference and scientific basis for improving the hospital environment and clinical rational use of antibiotics.Methods:1.The PM10 tests were performed in the wards of the two selected hospital buildings(Nos.1 and 9 buildings)of Liaoning Province Hospital.In No.1 building,three departments with the highest concentration of PM10,and two departments with the lowest concentration of PM10 were selected.In No.9 building,two departments with the highest concentration of PM10,and two departments with the lowest PM10 concentration were selected.Among these selected nine departments,two wards(a total of 18 wards)were chosen for each department,and the PM2.5 and PM10 content was ascertained.At the same time,among these selected wards,the bacterial and fungal cultures were accomplished by passive sedimentation method and the indoor dustsamples were collected and then Real-time PCR was used to detect bacterial and fungal content in dust samples and ATP bioluminescence assay was performed to detect the bio-fluorescence content.At the same time,the two student dormitories of Northeastern University were used as the reference for the natural environment,and all the above environmental indicators were tested at the same time.Through the analysis of the above indicators,we tried to find a comprehensive method to evaluate the environmental quality of the wards,and select optimization indicators.2.Microbial samples were quantified and identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALDI-TOF MS)to evaluate whether there is an imbalance in the environmental micro-ecology of the wards.3.The PM2.5 content was performed in the wards of the patients,who infected with the three common Gram-negative bacteria and four common Gram-positive bacteria detected by the microbiology laboratory,and the association of exposure to PM2.5 and susceptibility to common bacteria was analyzed.4.Biofilm-forming capacities were evaluated using the crystal violet staining approch,and the relationship between biofilm formation and antibiotic resistance in clinical isolates of P.aeruginosa was examined.For the inpatients,the common seven antibacterial consumption and the bacteria resistance of common pathogens were investigated.Through statistical analysis,the relationship between the bacterial resistance width and the usage of antibiotics,as well as the relationship between bacterial resistance and antimicrobial consumption were analyzed.Results:1.Although the studied indices were relatively independent,the PM2.5concentration was correlated with bacterial CFUs determined by passive sedimentation method,bacterial and fungal counts measured by Real-time PCR,and ATP bioluminescence assay(p<0.05).2.The composition of microorganisms in the air of hospital wards differed from that of student dormitories.The dominant genera in hospital wards were Staphylococcus,Micrococcus,Corynebacterium,Kocuria,Bacillus,Streptococcus,Moraxella,and Enterococcus.There were differences in microbial ecology between Respiration Dept.III and other hospital departments.The dominant bacteria in student dormitories were Staphylococcus,Micrococcus,Bacillus,and Moraxella.Additionally,11.1% of bacteriain hospital wards and 27.3% of bacteria in student dormitories were not identified.Five strains of P.aeruginosa were isolated from the ICU samples on the surface of the bedside table.3.The susceptibility of A.baumannii and P.aeruginosa in different PM2.5 exposure was statistically significant(P<0.05),while the susceptibility of K.pneumoniae,S.aureus,E.Faecium,E.faecalis and S.epidermidis in different PM2.5 exposure was not founded.4.Among 103 strains of P.aeruginosa isolated from clinical specimens,the strains which was resistant to gentamicin,piperacillin,ciprofloxacin,imipenem,meropenem,tobramycin,ceftazidime,cefepime and levofloxacin,the biofilm-forming abilities were higher than those of non-resistance,and the difference was statistically significant(p<0.05),and the biofilm-forming abilitiy of P.aeruginosa was positively correlated with the drug resistance width(P<0.001).Among the three Gram-negative bacteria,including A.baumannii and K.pneumonia,cefoperazone/sulbactam,amikacin and imipenem caused a significantly increase in bacterial resistance width(p<0.05).Levofloxacin caused an increase in the resistance width of both of A.baumannii and K.pneumoniae.The resistance width of K.pneumoniae was increased by using tigecycline,moxifloxacin,meropenem and cefotaxime sodium(p<0.05),and the resistance width of P.aeruginosa was increased by the usage of piperacillin/tazobactam(p<0.05).Cefodizime increased the resistance width of A.baumannii significantly(p<0.01),however,it significantly reduced the resistance width of P.aeruginosa(p<0.01).The use of amikacin and vancomycin resulted in an increase in the resistance width of S.aureus(p<0.05).The rate of resistance of A.baumannii to imipenem had a positive correlation with the usage of imipenem,and the rate of resistance of A.baumannii to tigecycline was positively associated with the usage of Levofloxacin.The resistance rates of K.pneumoniae to ceftazidime,gentamicin,meropenem and imipenem were positively correlated with the consumption of imipenem(p<0.05).A positive correlation was found between the consumption of levofloxacin and the resistance of K.pneumoniae to ceftazidime(p<0.05),while,a negative correlation was found between the consumption of levofloxacin and the resistance to meropenem(p<0.05).The rate of resistance of P.aeruginosa to cefazolin was positively associated with the usage of piperacillin/tazobactam and negatively associated with the usage of amikacin(p<0.05),in addition,the rate of resistance to ceftazidime was negatively associated with theusage of amikacin(p<0.05).Conclusions:1.The assessment of environmental quality of hospital general wards should be based on comprehensive analysis with multiple indicators.Moreover,PM2.5 could indirectly reflect the microbial pollution in the air in the wards,and can be used as a simple and highly efficient index for comprehensive evaluation of the environmental quality of hospital wards.2.Microbial diversity in hospital wards tended to be low,indicating that there may be imbalances in the microbial ecology of these environments,which may be closely related to hospital-associated infections.In addition,there may be contamination or colonization of P.aeruginosa in the ICU.3.In hospital wards,when exposed to different concentrations of PM2.5,the susceptibility of bacteria is different.With the concentration of PM2.5 increased,the susceptibility of P.aeruginosa increased,while the susceptibility of A.baumannii decreased.The correlation between PM2.5 concentrations and the susceptibility of K.pneumoniae and the four common Gram-positive bacteria was not found.4.The use of antibiotics constitutes an important environmental factor affecting the bacterial resistance,and the effects and mechanisms of different antibiotics on different bacteria were various. |
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