| Objective: To analyze the isolation of strains,the distribution of clinical departments,the source of specimens,the changes of drug resistance and defined daily doses(DDDs)of imipenem-resistant pseudomonas aeruginosa(IRPA)infection in a hospital in the past 5years.To analyze the antibacterial effect of matrine on IRPA;To investigate whether matrine has a regulatory effect on the IRPA quorum sensing system.Methods:(1)The IRPA infection cases in a hospital from 2017 to 2021 were retrospectively analyzed(duplicate isolated strains were eliminated),and the isolation of IRPA-infected strains,the distribution of clinical departments,the source of specimens,the changes of drug resistance and their DDDs were statistically counted.(2)We Collected 13 IRPA strains isolated from January 2022 to September 2022,determined the minimum inhibitory concentration(MIC)of matrine and imipenem by microdilution,set the original NC group,1/8 MIC matrine group,1/8 MIC imipenem + 1/8 MIC matrine group synchronous culture,observe the antibacterial effect in vitro,determine the optical density(OD)value of bacterial growth 0-10 h,draw the growth curve,and observe the bacterial growth trend between groups to summarize.(3)The relative expression of las R/lasl,rhl R/rhll and pqs E genes that were isolated from January 2022 to September 2022 were collected,and the more differential one was selected to determine the regulatory effect of matrine on quorum sensing(QS)system of the original strain,1/8 MIC imipenem + 1/8 MIC matrine strain.Results:(1)The detection rate of IRPA decreased year by year from 2017 to 2021,with an average of 26.71%.IRPA was mainly distributed in the Department of Cadre Health Ward,ICU and Department of Respiratory Medicine,with composition ratios of 54.76%,11.85%and 8.26%,respectively.The highest IRPA detection rate was 44.30%,in ICU.The detection rate of IRPA in cadre health wards is decreasing year by year(P<0.05).IRPA was mainly separated from sputum,urine and bronchoalveolar lavage fluid,with composition ratios of80.61%,5.92% and 5.39%,respectively.The detection rate of IRPA sputum samples(29.01%)was higher than that of non-sputum samples(20.01%),and it showed a decreasing trend year by year,and the difference was statistically significant(P<0.05).The highest IRPA detection rate was 54.17%,in throat swab.The resistance rates of seven drugs in IRPA,including piperacillin,piperacillin/tazobactam,ceftazidime,amikacin,gentamicin,tobramycin and levofloxacin,increased first and then decreased in 2020.Meropenem and ciprofloxacin rose first and then fell in 2021;With the exception of meropenem,the difference of resistance rates in other drugs was statistically significant(P<0.05).From 2017 to 2021,IRPA had low resistance to amikacin,gentamicin and tobramycin,and the remaining seven antibacterial drugs had a strong degree of resistance,especially meropenem with resistance rate of more than 80%.During the past 5 years,the top three with high DDDs among commonly used antibacterial drugs in the hospital were ceftazidime,levofloxacin,and gentamicin,and the IRPA resistance rate had not linear relationship with DDDs of commonly used antibacterial drugs DDDs(P>0.05).Total DDDs have been decreasing year by year since 2018.(2)The MIC values of matrine and imipenem were determined by microdilution method of 13 IRPA strains isolated from January 2022 to September 2022,and the results obtained were MIC50 of matrine was 64 mg/m L and MIC50 of imipenem was 16 μg/m L,both of which had bacteriostatic effects.Compared with the NC group,the 1/8 MIC(8 mg/m L)matrine group had a significant inhibitory effect on IRPA(P<0.05).The bacteriostatic effect of 1/8 MIC(2μg/m L)imipenem + 1/8 MIC(8 mg/m L)matrine group was stronger than that in the matrine group(P<0.05).(3)Quantitative real-time polymerase chain reactionq(QPCR)results showed that compared with the original strain NC after the strains acccepted 1/8 MIC(8mg/m L)matrine,1/8 MIC(8 mg/m L)matrine group inhibited the expression of las R,lasl,rhl R,rhll and pqs E genes of IRPA(P <0.05)。Compared with IRPA strain used with 1/8MIC(8 mg/m L)matrine,IRPA strains used with 1/8 MIC(8 mg/m L)matrine+1/8 MIC(2μg/m L)imipenem had lower expression abundance of las R and rhl R genes(P <0.05),showing stronger inhibition;The expression abundance of rhll gene was higher than that of IRPA strains(P<0.05)used with 1/8 MIC(8mg/m L)matrine,and the inhibitory effect was weaker;there was no significant comparison between pqs E and lasl genomes(P>0.05).Conclusions: IRPA is mainly distributed in cadre health wards,the source of specimens is mainly sputum,the detection rate is decreasing year by year,the rate of IRPA resistance has been controlled to some extent in the past 5 years,which is not linear relationship with DDDs.The multi-drug resistance is still relatively serious and hospitals should strengthen various infection prevention and control measures to effectively control the resistance and infection of IRPA.Matrine has an inhibitory effect on IRPA,and the MIC50 value is 64mg/m L.Under the condition of 1/8 MIC martine,the matrine group had antibacterial effect on IRPA,and the antibacterial effect of the combination group was better than that of the matrine monotherapy group,and there was no resistance.Under the condition of 1/8 MIC,the las R,lasl,rhl R,rhll and pqs E genes were inhibited;Combination of drugs can inhibit the expression of las R and rhl R genes;The expression abundance of rhll gene was weakened compared with that of single matrine,which indicated that the combination drugs had a weaker inhibitory effect on rhll gene than that of matrine alone.There was no significance in comparing pqs E and lasl genes between single agents and combinations. |
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