Diversity Analysis Of Biofilm Bacteria On Tracheal Tubes Removed From Intubated Neonates

Part Ⅰ: Diversity Analysis of Biofilm Bacteria on Tracheal TubesRemoved from Intubated Neonates by PCR-DGGE【Objective】 The catheter-related infections caused by mechanicalventilation has become a difficult clinical problem, and it is related to theformation of an adherent matrix of bacteria, which is termed “biofilm”(BF),on the surface of the implanted material. The majority of natural biofilms areformed by multiple bacterial species. However, there always only one orlimited species were detected on tracheal tubes removed from intubatedneonates by using traditional methods including bacterium culture andantigen detection. The aims of this study is to observe the bacterialcommunities diversity of BF on ETTs.【Methods】Forty-nine ETTs were obtained from40neonates onmechanical ventilator (from October2012to March2013) in Department ofNeonatology of Children’s Hospital, Chongqing Medical University. DGGEprofiling of16S rDNA gene amplicons was used to assess the diversity of thebacterial population by using the software of quantity one. 【Results】There were11-24bands inAgroup,7-18bandsinBgroup,5-11in C group, and2-22in D group. Sixteen ETTs samples were collectedin different stages of diseases from7newborns. In the longer indwellingtime of6/7newborns’ ETTs, the Shanon-wiener indexes were less. Amongsix samples from different basic illnesses, and there were differentShanon-wiener indexes.【Conclusions】The ETT-BF compositional diversity was confirmedand the appearance of dominant bacteria may promote the foundation of BF.Part Ⅱ: Bacterial species of Biofilm on Tracheal Tubes Removedfrom Intubated Neonates by TA Cloning Kit and sequencing【O bjective】To investigate the distribution of bacteria and commondominant bacteria in ETT-BF.【M ethods】 TACloning Kit and sequencing【R esults】The result of molecular cloning and sequencing for40dominant bands showed that all samples contained Klebsiella SP.,75.5%hadStreptococcus SP.,71.4%had Pseudomonas SP., and93.9%had Unculturedbacterium. There were27positive results of sputum culture from13newborns, including14strains of Klebsiella pneumoniae,9strains ofnormal microflora,2strains of Acinetobacter baumannii, enterobactercloacae, and non-cultured bacterium in each case.【C onclusions】16S rDNA PCR-DGGE could produce a more complete picture of bacterial community than traditional bacterium culturemethod. The result of the traditional bacterium culture method as the “GoldStandard” of clinical diagnosis of bacterial infectious diseases is partial.Klebsiella, Streptococcus and Pseudomonas were common dominantbacteria in ETT-BF.