| Pseudomonas aeruginosa (PA) is a common clinical isolate, which played avery important role in hospital infections, such as ventilating respiratory infections,the secondary burning infections and cystic fibrosis patients with secondarypneumonia. Pseudomonas aeruginosa clincal isolates always resistant to diverseantibiotics (such as some β-lactams, quinolones, tetracyclines, and chloramphenicol),as a result, it finally caused the clinical treatments fell into a difficult situation. Therehas many reasons to explain the resistance of PA, one of which is the formation of thebacterial biofilm (BF). Bacterial biofilm, as known as bacterial-films, refers to thebacteria adhered on the surface of the biological materials (such as medical organicmaterials or body mucosal surface), then secreted polysaccharide matrix, the fiberprotein, lipoprotein and polysaccharide-protein complexes etc, as the bacteriaattached to each other, it will be wrapped up in its own bacteria biofilms, formed adense membrane and lead to multi-resistance.As the polysaccharide matrix is the essential condition to biofilm forming, Arethere any effects to form biofilm for PA on Diabetic patients with high glucoseenvironment? The aim of the present study is to investigate the different glucoseconcentrations on biofilm formation of Pseudomonas aeruginosa, thus providing thetreatment guide for diabetic patients with PA infection in clinic.We collected42Pseudomonas aeruginosa clinical isolates, detected thesensitivity of these strains, evaluated the ability of biofilms formation, analyzed thecorrelation between drug resistance and the ability of biofilms formation, andresearched the impact of different concentrations of glucose on the ability and theprocess of the biofilm formation.1. Correlation analysis on the biofilm-forming ability and antibiotic resistance ofPseudomonas aeruginosa clinical isolatesStrain Source:42Pseudomonas aeruginosa were continuously collected from March 2012to June2012in the second hospital of Shanxi Medical University. All strainswere identified by VITEK-2system.Methods: Plate and crystal violet staining were used to construct the model ofPseudomonas aeruginosa biofilm formation, by which the biofilm-forming ability of42clinical isolates was analyzed quantitatively. The antibiotic resistance of isolateswere determined by the agar doubling dilution method. The relationship betweenbiofilm-forming ability and antibiotic resistance was analyzed by SPSS (Edition16.0).Results: The resistance rate of42clinical isolates of Pseudomonas aeruginosa toantibiotic followed up: amikacin was2.4%; ceftazidime and piperacillin/sulbactamwas11.9%respectively; levofloxacin was14.2%: piperacillin was19.0%; aztreonamwas28.6%; cefperazone-sulbactam was35.7%; aztreonam was40.5%. To the42isolates,41(97.7%) had biofilm-forming ability. In which,19(45.2%) isolates hasweak biofilm-forming ability,22(52.4%) has strong biofilm-forming ability, as1(2.4%) couldn’t form biofilm. With the biofilm-forming ability enhanced, theresistance of Pseudomonas aeruginosa to cefperazone-sulbactam increasedcorresponding.2. Detect different glucose concentrations on the abililty of biofilm formation ofPseudomonas aeruginosa by semi-quantitative experimentStrain Source:22Pseudomonas aeruginosa which has strong biofilm-formationability was selected from the first experiment.Methods: Pseudomonas aeruginosa biomaterial infection model was cultured in7different concentrations of glucose. Combined with crystal violet dye,semi-quantified was performed to analyze the biofilm-forming ability.Results: Semi-quantitative experiments showed that as the increasing concentrationof glucose in the culture medium, the ability of22bacteria biofilm formationshowed raising trend (all of the slope of the analogy line were positive), wherein,4strains had apparently raising trend when glucose concentration was not less then11.1mmol/L, the slope of the analogy line was between0.025and0.031; the reststrains were raised unobviously, the slope was from0.004to0.019. 3．Observe the impact of different glucose concentration on Pseudomonasaeruginosa biofilm formationStrain Source: Select Pseudomonas aeruginosa from the second experiment, whichanalogy line slope was0.031.Methods: Pseudomonas aeruginosa model of biomaterial infection was cultured in7different concentrations of glucose, using confocal laser scanning microscope (CLSM)to observe the forming process and thickness of biofilms.Results: CLSM images demonstrated that: compared with no glucose group andlower concentration glucose group, there showed faster speed, less mature time,stronger adhesion ability and thicker thickness of biofilms in≥11.1mmol/L glucoseconcentration group (P <0.05).The above results show:1、Amikacin remained best susceptibility against Pseudomonas aeruginosa clinicalisolates; better susceptibility to ceftazidime, piperacillin/sulbactam, levofloxacin,piperacillin; worst susceptibility to aztreonam and cefoperazone/sulbactamrelatively.2、 Positive rate of biofilm-forming ability was high, and the resistance ofPseudomonas aeruginosa was positively associated with the biofilm-formingability.（P=0.047）.3、To biofilm-forming positive strains for PA, the existence of glucose had inducingeffect on PA biofilm formation in the growth environment; with the increasingconcentration of glucose, the speed of biofilms formation was faster, the maturetime was less than before, and the adhesion ability was stronger more.4、When glucose-concentration was above the level of11.1mmol/L,for PA, thebiofilms thickness was increasing gradually (P<0.05); when glucose-concentration was above20mmol/L, the thickness was significantlythicker than normal（P<0.01）. |
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