| Part Ⅰ Effects of different pretreatment methods on microbial recovery of infected tissuesPurpose: To evaluate the effects of different pretreatment methods on the degree of microbial recovery in infected tissues.Methods: Standard strains of Staphylococcus aureus(SA),Escherichia coli(EC)and Candida albicans(CA)were used to construct single-surface,full-surface,and internal infection models in sterile pork tissue.Using manual milling(MM),mechanical homogenization(MH),ultrasonic lysis(UL),dithiothreitol(DTT),and direct culture(DC)to treat the infection models,the ability of the different pretreatment methods to achieve pathogen recovery in the different bacterial infection models was compared.Results: Regardless of whether the single-surface or full-surface infection model was used in SA,EC,and CA infection,the microbial acquisition in the MH group was significantly higher than that in the MM(P <0.01),UL(P <0.01)and DC groups(P <0.01),but there was no significant difference compared with that in the DTT group(P> 0.05).In the internal infection model,regardless of SA,EC,or CA infection,the microbial acquisition of the MH group was significantly higher than that of the MM(P <0.01),UL(P <0.01),DTT(P <0.01),and DC groups(P <0.01).Conclusions: The effects of MH and DTT were significantly better than those of DC,UL and MM for the isolation of bacteria in tissue.In addition,contamination was not common with MH and DTT,and these methods can be used to process multiple tissue samples at the same time,which can further improve the efficiency of clinical microbial diagnosis.Part Ⅱ Effects of Different Pretreatment Methods on Diagnostic Efficiency of Microbial Cultures of Periprosthetic Joint Infection Tissue SpecimensPurpose : The current tissue culture methods routinely used in clinical practice have low sensitivity.One of the main reasons is that bacteria are not easy to release without proper pretreatment.The aim of this study was to optimize the pretreatment methods of tissue specimens to improve the sensitivity of tissue microbial culture.Methods:A total of 46 patients were prospectively included in our center for revision surgery due to periprosthetic joint infection and aseptic failure.periprosthetic tissues were assigned to the tissue-Mechanical Homogenization(T-MH)group,the tissue-manual milling(T-MM)group,the tissue-DL-dithiothreitol(T-DTT)group,the tissue-sonication fluid sonication fluid(T-UL)group,and the tissue-direct culture(T-DC)group.Results:28 cases of PJI and 18 cases of AF were included.Among 28 PJI cases,23 cases had positive culture results via T-MH culture,22 cases via T-DTT culture,20 cases via T-UL culture,15 cases via T-MM culture,and 13 cases via T-DC culture.Fifteen cases had positive culture results in synovial fluid from joints(JF),while 18 cases has positive results in prosthetic sonication fluid.The sensitivities of the T-MH and T-DTT cultures were higher than those of other detection methods,and the differences were statistically significant compared with JF culture.Combining the two cultures can further increase the sensitivity without significantly decreasing the specificity.Conclusions : The tissue culture homogenization method has a higher sensitivity,and combined with the tissue dithiothreitol method,which requires no special equipment and has a simple and easy process,it can effectively improve the efficiency of PJI pathogen diagnosis. |
