Introduction Study Of The Mechanism Of Ceftazidime Influence Procalcitonin Produce In Rats

PrefaceEndotoxin , that is lipopolysaccharide , is the major component of the cell wall of the gram - negative bacteria. In sepsis, Systemic inflammatory response syndrome stimulated by endotoxin cause to injure of tissue cells.In past, we considered endotoxin released only when G- bacteriolysis. But endotoxin release was found in living G- bacteria recently. A lager amounts of endotoxin was induced by antimicrobial. Antimicrobial - induced endotoxin release may depend on antimicrobial class and concentration. In general, β - Lac-tams induced more endotoxin than aminoglycosides, and aminoglycosides more than quinolones. Inβ -Lactams, Ceftazidime produced significantly higher endotoxin than Imipenem. In study of endotoxin induced by different concentration of antibiotic, conclusion accepted is higher doses antimicrobial induced less endotoxin and lower doses antimicrobial induced higher edotoxin.Procalcitonin(PCT) is the prohormone of calcitonin ( CT). under normal metabolic conditions, PCT is produced and reserved in the C - cell of the thyroid gland and few in blood. So the concentration of PCT in health person very low or even cant detect( <0. 1ng/ml). Significant increased plasma PCT concentration are detected in severe system bacterial infection ( > 100 ng/ml).PCT synthesis can be mainly stimulate by bacterial endotoxins. PCT is initially detected in the plasma approximately 2 hours post injecting small quantities of bacterial endotoxin in healthy subjects, Levels then rise rapidly in 6 ~ 8 hours, reaching a plateau after 12 ~ 48 hours, falling to their baseline values within the following 2 ~ 3 days.Some studies about influence of endotoxin induced by antimicrobial release to sepsis are all detected cytokins syntheses increase caused by endotoxin. Up to date, No observation about the influence of antimicrobial use to PCT produce in vivo. Antimicrobial can induce the increase of PCT in plasma probably. In our test, we based on experience formerly, to test distinction of endotoxin release by E. coli induced by variation concentration ceftazidime, and examination further the effect to PCT produce in rats.Materials and MethodsCeftazidime were added to broth cultures with a certain bacterial intensity, final concentration of antibiotic was 0. 25 MIC ,0. 5MIC,1. OMIC,2. 0MIC,5. 0 MIC (MIC =0. 5 g/ml). growth control and negative control (no bacterial no antibiotic) were made simultaneously. Viable counts and morphology changes were observed after incubation for Oh, lh, 2h, 3h, 4h, 5h, 6h, 7h. 7 hours after incubation, samples obtained were filtered through a 0. 2jxm pore filter to exclude bacteria. Filtrate was divided two parts, reserved in pyrogen - free tubes.Sixty rats was divide to 6 groups balance weight and sex. Six groups received in tail - venous injection of 0. 25MIC, 0. 5MIC, 1. 0MIC,2. 0MIC, 5. 0MIC filtrates of antimicrobial - treated and control filtrates respectively ( 1. 5ml/rat, 100 times dilution). Obtained blood from venous behind eyes after 16h, serum was collected use to detecte PCT. Data were expressed as (x ± sD). ANOVA of completely radom design was used analyse the data.ResultsInfluence of ceftazidime against the growth of ATCC25922 Viable count of growth control increased upto 6.0 109CFU/L at 7h. Exposure to ceftazidime resulted in diverse extent fallen in viable count. At 4h of test, ceftazidime killed all bacteria at the concentration of 5MIC. viable count remain keep decline in 2.0MIC and 1.0MIC, but switch to increase after4h in O.25MICandO.5MIC.2. Influence of ceftazidime against morphology changes of ATCC25922 The morphology of growth control keep rod - shaped all time. No significantchanges in all cultures contain ceftazidime at 0h and 1h. Apart bacterial change to filamentous form in all cultures contain ceftazidime at 2h. All bacterial change to filamentous form at 3h and 4h. To the time of 6h and 7h, The quantity of filamentatous form in 0. 5MIC and 0. 25MIC significant more than 1. 0MIC and 2.0MIC.3. Influence of ceftazidime in different concentration against endotoxin produced by E. Coli ATCC25922. We found that the amount of endotoxin released increased following decline of antibiotic concentration. Significent difference was found between 0. 25MIC, 0. 5MIC and other cultures contain ceftazidime. However, no difference between 1.0MIC, 2.0MIC and 5.0MIC.Compared to growth control, endotoxin release of 0.25MIC higher and 1. 0MIC,2. 0MIC,5. 0MIC lower( P < 0. 05). No significant difference between 0. 5MIC and growth control.4. Filtrates of antimicrobial - treated by different concentration ceftazidime stimulated procalcitonin produce in rats.Filtrates obtained from E. coli cultures dealing with different concentration ceftazidime stimulated rats, the number of procalcitonin induced increased following decline of antibiotic concentration. Significent difference between any two concentration.Compared to growth control, procalcitonin produce of 0. 25MIC and 0. 5MIC higher and 1.0MIC.2.0MIC.5.0MIC lower(P <0.05).5. Correlation analysis was made between procalcitonin and concentration of ceftazidime.Strong negative correlation was found between procalcitonin and concentration of ceftazidime. r = -0.77, significant analyse p <0.001.DiscussionCeftazidime ( CAZ ) is a broad - spectrum semisynthesis third - generation cephalosporin use to injection. It has excellent activity to different kinds of bac-teria. Ceftazidime is a kind of bacteria - killed drug, through binding with penicillin - binding protain ( PBPs) which invoved in cell wall structure inhibit the cross - linking of the peptidoglycan strands to make bacteria killed.In our test, ceftazidime killed all bacteria in 4h at the concentration of 5. OMIC, Implicating strong bactericidel activity. After exposure to ceftazidime 2h, bacterial morphology changed to filamentation and keep the morphology until to 7h.Bacteria morphology changing when expose to ceftazidime is related to category of PBPs which antimicrobial binded. Ceftazidime bind to PBPS - 3 mainly which is responsible for cell septation. So the cell cant break up and growing in longitude formating filamentous form, with a raise in biomass and with concurrent synthesis of endotoxin before bacteriolysis.In our test, we observed that the quantity of endotoxin release increased following decline of antimicrobial concentration. This implicated that lower concentration CAZ induced more endotoxin and higher concentration induced fewer endotoxin. similar result with Jackson JJ. Liu y have advised lower concentrations of ceftazidime cant killed E. coli rapidly, forming large number of filamentous form enhanced the release of endotoxin. Since we suggest that the antimicrobial concentration should higher than 1. OMIC at lest, not lower than 4 ~ 10MIC may as well when therapy infection disease in clinic.Quantity of endotoxin of growth control between 0. 25MIC and 0. 5MIC. There is significant difference between growth control and 0. 25MIC, but no difference with 0. 5MIC. It is implicated that endotoxin induced by lower than 1. OMIC CAZ equal to or higher than that released by bacterial not therapy by antimicrobial. It,s support the theory of lower concentration CAZ induced more endotoxin.The concentration of antimicrobial have important effect on not only release of endotoxin but also liberation of cytokine caused by endotoxin.It is known that endotoxin is major evocator of procalcitonin. No study to investigate if the concentration of antimicrobial influence the produce of PCT and the extent of PCT produce in rats.Our studies in rats implicated that the produce of PCT in rats increased fol-lowing with the improved concentration of ceftazidime. Strong negative correlation was found between procalcitonin and concentration of ceftazidime ( r = -0. 77) , significant analyse p <0. 001. This implied lower concentration- CAZ induced more PCT and higher concentration induced fewer PCT. PCT induced by filtrates of expouse to 0.25 MIC and 0.5 MIC CAZ significant higher than growth control(P <0. 05) , indicate PCT induced by below 1. 0MIC CAZ even higher than that released by bacterial not therapy by antimicrobial.Some studies proved the procalcitonin is a inflammatory mediator. It can extend the reaction of inflammatory and make disease severe. So, It is necessary to prevent increase of PCT in blood.Acroding to our studies, in the process of therapy sepsis, concentration of Ceftazidime lower than 1.0MIC cause the release of endotoxin increased, result in produce large quatity of procalcitonin in vivo, enlarge the degree of inflammatory response, concentration of CAZ higher than 1.0MIC lead to bacteriolysis in short time, result in decline endotoxin release and slightly produce of procalcitonin in vivo, make inflammatory response relieve and eradicate. Therefore, we should consideration the effect of potential severer endotoxinemia for outcome of patients in the process of antibiotic therapy. We should use drugs in appropriate doses, control the sepsis rapidly, avoid appearance of endotoxinemia and procal-citoninemia.Conclusion1. Ceftazidime in different concentration can influence the growth and morphology of E. coil. CAZ in lower concentration can induce filamentous form of E. coil, result in higher release of endotoxin. CAZ in higher concentration as well as can induce filamentous form of E. coil, but because CAZ killed vast bacterial in short time, so endotoxin induced very few.2. Filtrates of E. coil treat with CAZ induced procalcitonin produce in rats. The concentration of CAZ and PCT presenting Strong negative correlation (r = -0.77) , significant analyse p <0. 001. lower concentration CAZ induced more PCT and higher concentration induced fewer PCT.