| Purpose Study the characters of CAUTIs in children, analyze the riskfactors and the susceptibility of antibiotics, thus to provide references to thediagnosis and medication of PA-CAUTIs. To discuss the effects ofquinolones signal molecule (PQS) on the virulence of Pseudomonasaeruginosa (PA).Methods Select the22cases of PA-CAUTIs in one hospital from Jan,2006to Jan,2012, collect their clinical information, laboratory results andradiological character, and to compare with the CAUTIs cased by E.coli ofthose random selected over the same period. Choose PAO1as theexperimental strain, divide into PQS group, PQS and inhibitor group,inhibitor group, and normal group. Use QPCR to detect the transcriptionallevel of the regulator gene ExsA and virulence protein gene ExoS of TypeIII Secretion System (T3SS); Use spectrophotometer to detect thePyocyanin generation; Incubating it with alveolar epithelial cells A549, usenutrient agar plate count to compare the adhersion and invasion of PAO1;Make a mouse peritonitis model, to observe the PQS’s effects on thesurvival time of the mouse.Results In those22PA-CAUTIs, the mean value of protein level is（32.25±13.81）mg/ml,19of them have hospitalizations,6have urinary operation history,7of them have long-term usa-ge of glucocorticoids orimmunosuppressive, and20have underlying disease.A total of22childrenwith26PA-CAUTIs episodes were compared to E.coli-CAUTIs.Comparing with E.coli-CAUTIs patients, children with PA-CAUTIs moreoften presented with a lower albumin(P=0.017), a history of urinaryoperation(P=0.03), more people have a history of urinary operation (P=0.03), a long-term usa-ge of glucocorticoids or immunosuppressive (P=0.044).Through multivariable logistic regression of those statistically variables univariate anylysis (with hospitalizations, long-term usage of glucocorticoidsor immunosuppressive, albumin, underlying disease and urinary operationhistories), and it turned out that underlying diseases (odds ratio8.500,95%CI1.513-47.761, P0.037)and with urinary operation histories (odds rate6.196,95%CI1.120-34.273, P=0.037)were proved as the independent riskfactors for PA-CAUTIs. Those PA bacterial strains have a36.36%resistance rate to piperacillin, aztreonam and gentamicin, a31.82%resistance rate to cefepime and ceftazidime, while the resistance rate(4.55%) to carbapenem antibiotics is relatively lower, only sensitive tobacillosporin. The increase or decrease of PQS do not affect the growing ofthe PAO1. Comparing with the normal group, the ExsA and its controlledexpressed ExoS virulence protein gene transcriptional level of PQS groupincreased obviously; The pyocyanin generated by PAO1of PQS groupincrease obviously too, while it decreased clearly in the inhibitor group;When its incubating with A549cells, the adhesion and invasion of PAO1ofinhibitor group decreased significantly; The survival time of the mouse ofPeritonitis model in PQS group reduced obviously (P＜0.01). Thetranscriptional level of inhibitor group is reduced, the difference isstatistically significant. Comparing with the normal group, thetranscriptional level of ExsA in inhibitor group has no obvious difference, the adhesion and invasion of PAO1stay unchanged in PQSgroup.(P>0.05).Conclusion Underlying diseases and the urinary operation histories are theindependent risk factors of the occurrence of PA-CAUTIs,carbapenemantibiotics and bacillosporin can be considered as the priority drugs for itstreatment. In the process of PA’s infection on its host, PQS can maintain itsadhesion and invasion, and the concentration of PQS and the generation ofpyocyanin are positively correlated, eventually made it a negativecorrelation for the survival time of its host. |
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