The Analysis of the Autoinducer Gene Expression Related Quorum Sensing Mechanism in Catheter Associated Urinary Tract Infection / 대한비뇨기과학회지

Purpose: Catheter associated urinary tract infection (CAUTI) frequently occurs in the patients with an indwelling Foley catheter, and it can cause serious morbidity or mortality. However, there have been no reports about quorum sensing mechanisms in indwelling Foley catheter. It's our purpose to find out the quorum sensing mechanisms of isolated bacteria from biofilm in Foley catheters. Materials and Methods: Silicone Foley catheters were placed in 90 patients with neurogenic bladders. At the 3rd, 5th, 7th, 14th and 30th day after the catheters were placed, the catheters were removed and the biofilm formations were evaluated by routine culture and microscopy. The ygaG gene, which was reported to be an autoinducer synthase gene was carried out cloning in E. coli. The quantity of the mRNA expression of the ygaG gene was analyzed according to the time by competitive reverse transcription polymerase chain reaction (RT-PCR). Results: 289 different types of bacteria were isolated by cultivation. The most common species were Pseudomonas, Klebsiella, Serratia, Proteus and Escherichia species. The autoinducer synthase gene, such as the ygaG gene for Escherichia coli, was detected by RT-PCR. On competitive RT-PCR of the ygaG gene, the mRNA expression was 3.77x10(9)copies/microliter at the 3rd day, 5.94x10(7)copies/microliter at the 5th day, 8.07x10(7)copies/microliter at the 7th day, 2.51x10(6)copies/microliter at the 14th day and 6.81x10(8)copies/microliter at the 30th day. Therefore, the expression of the autoinducer synthase gene was observed at the early insertion period and it was then maintained. Conclusions: This is the first study to document the autoinducer synthase gene expression associated quorum sensing mechanism in CAUTI. The quorum sensing mechanism may be a new target for the management of CAUTI.

Long-term Effects of Antibiotic-coated Foley Catheter on Bacterial Biofilm Formations / 대한비뇨기과학회지

PURPOSE: A catheter-associated urinary tract infection, which frequently occurs in patients with an indwelling Foley catheter, can cause serious morbidity or mortality. Recently, antibiotic coated Foley catheters, to prevent catheter-associated urinary tract infections, have become commercially available. This study investigated the long-term effects of the use of antibiotic-coated Foley catheters on biofilm formations. MATERIALS AND METHODS: Silicone Foley or antibiotic-coated Foley catheters were indwelled in 72 patients with a neurogenic bladder. Each catheter was removed 1, 3, 5, 7, 14 and 28 days after insertion. The cell densities of the biofilm bacteria were evaluated by counting the number of colonies on plate cultures. The biofilm formations on the catheters were evaluated by scanning electron microscopy. The inner surface morphology of the catheter was imaged by field emission scanning electron microscopy (Philips-XL20SFEG), at 10kV, following gold sputtering for electrical conductance. Six catheters were studied in each group, and the means calculated for comparisons. RESULTS: Thick bacterial biofilms were observed on both the antibiotic- coated and silicone Foley catheters 7 days after insertion. There were no significant differences in the cell densities of the biofilm bacteria between the two types of catheter during days 7-28 after insertion (p<0.05). Two to three species of bacteria were isolated from the catheters in each patient; the most common species were Pseudomonas, Klebsiella, Serratia, Proteus species and Escherichia coli. CONCLUSIONS: The antibiotic-coated Foley catheters showed no preventive effects on the biofilm formations after 7 days of indwelling compared with the silicone Foley catheters. Our data suggest that the routine use of antibiotic-coated Foley catheters to prevent catheter-associated infection in patients with a neurogenic bladder is not reasonable. The emergence of resistance associated with antibiotic-coated catheters should be evaluated.

Chest radiographic findings of leptospirosis

1. A study on chest radiographic findings of 54 cases with pneumonia like symptoms was performed. Of 54 cases,8 cases were confirmed to be leptospirosis and 7 cases were leptospirosis combined with Korean hemorrhagic fever.2. Of 8 cases of leptospirosis, 4 cases showed abnormal chest radiographic findings: acinar nodular type 2,massive cofluent consolidation type 2. Of 7 cases of leptospirosis combined with Korean hemorrhagic fever: acinarnodular type 3, massive confluent consolidation type1, and increased interstitial markings type 1 respectively. 3.It was considered to be difficult to diagnose the leptospirosis on chest radiographic findings alone, especiallythe case combined with Korean hemorrhagic fever.