ABSTRACT
AIM: Given the biofilm formation abili- ty of different ST-type Klebsiella pneumoniae, our study was aimed at exploring the inhibitory and clearance of azithromycin combined with levofloxacin on the biofilm of Klebsiella pneumoniae of different ST-types and providing a new strategy for the prevention of biofilm formation in the treatment of post-infectious Klebsiella pneumoniae. METHODS: 9 strains of Klebsiella pneumoniae from all susceptibility groups, 19 strains of Klebsiella pneumoniae producing extended-spectrum β - lactamases (ESBLs), and 37 strains of Carbapenem-resistant Klebsiella pneumoniae (CRKP) were randomly collected from the samples of patients hospitalized in the First Affiliated Hospital of Wannan Medical College from August 2019 to November 2021. The isolates were identified using VITEK MS IVD KB V3.2 and VITEK 2-Compact 60. Multilocus sequence typing (MLST) was performed to analyze the homology of each strain; crystal violet staining was used for semi -quantitative detection of biofilm to compare the differences in biofilm formation ability between different ST-type Klebsiella pneumoniae. Different ST-type strains were selected, and the partial inhibitory concentration index (FICI) was calculated by micro broth dilution method to judge the combination effect and select the optimal combination concentration; crystalline violet staining method was used to investigate the inhibition and clearance effect of azithromycin combined with levofloxacin on the biofilm of different ST-type Klebsiella pneumoniae; laser scanning confocal fluorescence microscopy was used to observe the structural changes of the biofilm of Klebsiella pneumoniae before and after the effect of the antibacterial drugs. RESULTS: MLST typing results showed that the sensitive group of Klebsiella pneumoniae strains had 8 sequences such as ST86, ST727, etc., the ESBLs group strains belonged to 14 sequence types such as ST15, ST37, ST11, etc., of which ST15 accounted for 26.32% (5 / 19). The CRKP group strains belonged to 9 sequence types such as ST11, ST15, ST656, etc., of which ST11 accounted for 48.65% (18/37), ST15 accounted for 27.03% (10/37); ST15 (ESBLs), ST11 (CRKP), ST15 (CRKP) type Klebsiella pneumoniae biofilms all reached maturity on the 5th day, the ST15 (ESBLs) group had a stronger ability to produce material to be membranous than the ST15 (CRKP) group. The ST11 (CRKP) group had a stronger ability to produce material to be membranous than the ST15 (CRKP) group (Pazithromycin>levofloxacin, and the highest clearance rate was 44.79%. CONCLUSION: There are differences in biofilm formation ability between different ST-type Klebsiella pneumoniae, and azithromycin combined with levofloxacin has a better inhibitory effect on different ST-type Klebsiella pneumoniae biofilm, conbined application can be used in the treatment of biofilm infections early stage.
ABSTRACT
AIM: To study the inhibitory and scavenging effects of ambroxol combined with levofloxacin on the bacterial biofilm of Klebsiella pneumoniae, and to provide a new strategy to treat and antagonize the formation of the biofilm. METHODS: We collected Klebsiella pneumoniae of different resistance and divided them into sensitive group (wild bacteria group), ESBLs group and CRKP group with 15 strains in each group and performed biological semi-quantitative detection of its biofilm by crystalline violet staining method. After selecting 3 strains with similar membrane yields from each group, we determined the minimum inhibitory concentration (MIC) of ambroxol and levofloxacin against Klebsiella pneumoniae by micro broth dilution method.In addition, we determined the effects of ambroxol in different concentrations on the MIC of levfloxacin by the micrdilution checkerboard techniques and calculated the partial inhibitory concentration index (FIC) to determine the joint effect and select the best synergistic concentration. Finally, the effects of ambroxol and levofloxacin in different concentrations on the inhibition formation test and removal test of Klebsiella pneumoniae biofilm were observed by crystal violet method combined with confocal laser scanning microscopy. RESULTS: We found that all three groups of bacterial biofilms became mature on the 5th day, and the sensitive group was easier to form and produce biofilm more than the ESBLs and CRKP groups (F=3.725, P=0.032). It was showed that the geometric average of levofloxacin MIC value in the three groups decreased significantly. And the selected strains all showed a synergistic effect on the two-drug combination.In the biofilm test, as the concentration of ambroxol increased, its inhibition rate reached more than 75%, but its biofilm removal rate did not reach 70%. CONCLUSION: Our study support that ambroxol combined with levofloxacin can inhibit the bacterial biofilm of Klebsiella pneumoniae early, and its optimal synergistic concentration is 0.49 mg/mL (ambroxol) + 4 μg/mL (levofloxacin).
ABSTRACT
Objective To explore the levels and the significance of IL-11 and soluble glycoprotein 130(sgp130) in the treatment of new-diagnosed acute leukemia(AL) during the induced remission. Methods The levels of IL-11 and sgpl30 in 47 patients with acute leukemia were determined by ELISA respectively before treatment and after completed remission(CR), and the number of white blood cell (WBC) and platelet (Plt) were valued by hametometry. Results Plasma IL-11 level of AL patients was significantly lower than normal (P ＜0.05), and increased obviously to the normal level when complete remission was achieved. And it correlated with PLT counts. While sgp130 level was higher than normal (P＜0.05),and declined after CR and correlated with WBC counts. Conclusion The plasma IL-11 and sgp130 levels can be helpful for confirming the diagnosis,evaluating the efficiency and predicting the prognosis of AL.