Study Of Decontamination Protocol For Donor Kidney Against Carbapenem-resistant Gram-negative Bacteria

BackgroundKidney transplantation is the best treatment for end-stage renal decease.Yet,the infection problem is still the major factor threatening recipients’ prognosis,and donorderived infection(DDI)is the main type in the early stage after operation.The incidence of DDI could be as high as 10%,with bacteria being the main pathogens,of which carbapenem-resistant gram-negative bacteria(CRGNB)dominanting at about 73.3%.DDI caused by CRGNB often leads to serious adverse events,such as graft loss or recipient death,the incidence of which can occur in up to 59%.Pathogens of DDI can come from any part of the donor-to-transplantation process.The consensus has formed norms for screening,diagnosis and treatment of DDI prevention and control measures at the donor and recipient stages,which can reduce the incidence of DDI to a certain extent,but the prevention and control of CRGNB is still insufficient.The stage of isolated organ preservation is another intervention stage and pre-treatment to the graft with antibiotics at this stage could move the anti-infection gate forward,which may be a powerful measure for DDI prevention.However,there are no guidelines or consensus on decontamination,and most transplant centers that perform decontamination often use broad-spectrum antibiotics such as cephalosporins or aminoglycosides as the primary choice,which can clear most common,non-resistant pathogens but are often ineffective in decontaminating CRGNB,resulting in CRGNB-DDI and serious adverse outcomes.Therefore,there is an urgent clinical need to develop a donor kidney decontamination protocol against CRGNB to effectively reduce the incidence of associated DDI and improve patient prognosis,in which the choice of antibiotics is crucial.In the face of limited effective antibiotics for CRGNB,the previous decontamination exploration in our center found that colistin sulfate(CS)has a decontamination potential,and retrospective analysis showed that it was effective in reducing the incidence of CRGNB-DDI,which has a value of promotion.However,single-center retrospective analysis is limited in the level of evidence,and as CS is only available in China,the range of application is limmited.Therefore,it is extremely important to conduct studies with higher levels of evidence to further validate the efficacy and safety of this CS-based decontamination protocol,as well as to investigate alternative options to CS to further optimize the donor kidney decontamination protocol,which could help to improve the current decontamination dilemma,promote consensus and guideline formation,thus guide clinical practice,reduceg the incidence of CRGNB-DDI and improve the prognosis of kidney transplant recipients.Part Ⅰ: Clinical Study of Donor Kidney Decontamination Protocol Based on Colistin Sulfate to Reduce the Incidence of CRGNB-DDIObjectivesTo further study the efficacy and safety of donor kidney decontamination protocol based on colistin sulfate to reduce the incidence rate of CRGNB-DDI in kidney transplant recipient after operation.MethodsDesigned a multicenter prospective single-arm objective performance criteria clinical trial.According to the previous report on the incidence rate of CRGNB-DDI in kidney transplant recipients was about 37.7%,preset an aim that to reduce this rate to below 20%through using CS to decontaminate donor kidney.Recruited kidney transplant recipients from five domestic transplant centers and performed standard decontamination protocol on all kidneys of patients enrolled in this study.DDI was defined as occurring when the results of culture of the donor kidney’s preserved fluid prior to decontamination are consistent with the results of culture of the recipient’s routine drainage fluid or infected site specimen within 28 days postoperatively(including pathogen type and drug sensitivity).Mainly recorded culture results of related specimens,infection events including DDI,and some adverse events such as delayed graft function(DGF),rejection,et al.within 28 days after surgery,as well as performed historical control study to the previous data of decontamination by ceftizoxime in our center through propensity score matching,to evaluate the efficacy and safety of using CS for decontamination to reduce CRGNB-DDI.Results1.A total of 179 kidney transplant recipients from five transplant centers between April 1,2021 to July 31,2022 were enrolled in the study and 179 PFs were collected and decontaminated.The total contamination rate of PF was 64.8%(116/179).There were 34 PFs with CRGNB positive(19.0%,34/179),after decontamination of which no CRGNBDDI occurred in recipients corresponding to the 34 PFs.That meant the incidence rate of CRGNB-DDI was at present 0.0%(0/34)reaching the preset objective and it could be considered effective of decontamination by CS,so terminated the trail in advance.In the historical control to ceftizoxime,after propensity score matching the contamination rate of CRGNB in PF were similar(p>0.05)between two groups,while the incidence rate of CRGNB-DDI was significantly lower in CS group than in ceftizoxime group(0.00% vs.5.42%,p=0.0069).2.The main adverse events in recipients within post-operation day 28 were DGF(20.11%,36/179)and rejection(10.61%,19/179)which were similar to exiting reports.Median creatinine on postoperative days 3,10,and 28 were 277,126,and 124 μmol/L.Four recipients underwent graft removal due to rejection or thrombosis in graft artery or vein.Two patients died because of bleeding or acute respiratory and circulatory failure.No neurotoxic symptoms related to colistin sulfate was observed in patients.Conclusions1.The donor kidney decontamination protocol based on CS could significantly reduce the incidence rate of CRGNB-DDI in kidney transplant recipient after operation,demonstration high effectiveness.2.No evidence showed that adverse events including DGF and rejection were related to the decontamination procedure,and CS-related nephrotoxicity and neurotoxicity symptoms are not obvious,demonstrating good safety.Part Ⅱ: Study of the Simulating Decontamination Effect of Polymyxins on CRGNB in VitroObjectivesTo study the antibacterial effects of polymyxins including colistin sulfate(CS),polymyxin B sulfate(PB)and colistimethate sodium(CMS),as well as the present uasual decontamination choice in clinicl,amikacin(AK)on four kinds of CRGNB in at simulating decontamination condition in vitro,so as to provide references for expanding decontamination options.MethodsIsolated 13 clinical strains of CRGNB including CRKP,CRPA,CRAB and CREC.Simulating the PF decontamination process in previous clinical study,dissolved four antibiotics of intravenous forms in 1000 ml HCA-II PF at 0-4℃,and recorded the concentration as the base concentration of each drug,then set gradients of 0.5,1,2 and 4times of the base concentration recording as(1)(2)(3)(4).Mixed the bacterial suspension and various concentrations of drugs,also set up positive control group with bacterial suspension mixing with no drug PF and negative control group with only no drug PF.Put the mixture at 0-4℃ for 2-3h and then incubated in 37℃ for 18-20 h to count the colonies.For CRKP,the most common one of CRGNB,also tested the minimum bactericidal concentration(4℃-MBC)of the four antibiotics.The antibacterial effect was evaluated by bacterial inhibition rate which was calculated by(A-B)/A*100%(A referred to colony number in positive control group,B referred to colony number in experimental group).The bacterial inhibition rate was described by Mean±SD and using two-way analysis of variance(ANOVA)to compare the antibacterial variances of different drugs at different concentrations for different drug-resistant bacteria.Results1.The bacterial inhibition rates of the 4 antibiotics for CRKP showed as PB>CS>CMS>AK(P<0.05).And the bacterial inhibition rate of every drug at various concentration showed as(4)>(3)>(2)>(1)and(3)(4)were both significant different from(1)(2)respectively(P<0.05).At the concentration of clinical decontamination(2)the bacterial inhibition effect was PB>CS>CMS>AK with significant differences.The bacterial inhibition rate for CRAB showed as PB>CS>CMS>AK at every drug concentration but there was no significant differences between CS and CMS at concentration(2)(3)(4).The bacterial inhibition rate of PB,CS and CMS all showed as(4)>(3)>(2)>(1),in which CS and CMS only had significant differences between concentration(4)and others.At base concentration(2),the inhibition rate of PB was higher than the other three drugs(P<0.05).The bacterial inhibition rate for CRPA showed that the rate of PB was the highest at concentration(1)and basic concentration(2)(P<0.05).The trends of inhibition rates were both PB>CMS>AK(P<0.05)and CS>AK(P<0.05)at concentration(3)(4).The inhibition rates of 4 drugs increased with the growth of concentration,in which the rates of CS and CMS were both significantly higher at concentration(4)(3)than at concentration(1)(2)respectively,and the rates of PB and AK had no significant differences between each concentration.The bacterial inhibition rates of 4 drugs for CREC showed as PB>CS>CMS>AK(P<0.05),but the difference between CS and CMS was not statistically significant(P>0.05).The trend of inhibition rate was(4)>(3)>(2)>(1)with significant differences between(1)and(4)(3)respectively.At the concentration of clinical decontamination(2)the bacterial inhibition effect was PB the best(P<0.05).2.The ranges of 4℃-MBC of PB,CS,CMS and AK for CRKP were 8～128ug/ml,64～256ug/ml,≥512ug/ml and >512ug/ml respectively.The 4℃-MBC for each CRKP strain was PB<CS<CMS≤AK,which meant the susceptibility trend was in line with the overall inhibition rate trend,further proving the best inhibition effect of PB.Conclusions1.Under the simulated decontamination condition in this experiment,the bacteriostatic effect of different drugs on four kinds of CRGNB is the best in PB.2.The bacterial inhibition rate of each drug basically increases with the increase of concentration,and the rate of PB is significantly higher than that of CS under the concentration of clinical decontamination protocol,which shows a stronger clinical application prospect than CS.