Clinical significance of virulence-related genes of type III secretion system of Pseudomonas aeruginosa / 中华烧伤杂志

<p><b>OBJECTIVE</b>To study the clinical significance of virulence genes exo U and exo S of type III secretion system (TTSS) of Pseudomonas aeruginosa (PA).</p><p><b>METHODS</b>One hundred and eighty-nine clinical isolates of PA were collected from five hospitals. The incidence of virulence genes exo U and exo S in PA were determined with PCR. Minimum inhibitory concentration of anti-bacterial drug for PA was determined with microdilution method. The clinical features and outcomes of 60 hospitalized patients colonized or infected with exo U+/exo S- positive or exo U-/exo S+ positive PA isolated from sputum were analyzed retrospectively. Data were processed with chi-square test.</p><p><b>RESULTS</b>Among the 189 PA isolates, 85.2% (161/189) harbored TTSS genes, including exo U-/exo S+ type (120 isolates), exo U+/exo S- type (31 isolates), exo U-/exo S- type (7 isolates), and exo U+/exo S+ type (3 isolates). 72.0% (72/100) isolates from sputum and 81.5% (44/54) isolates from blood belonged to exo U-/exo S+ genotype. Compared with those of TTSS-negative isolates, the antimicrobial resistance of TTSS-positive isolates to cefoperazone/sulbactam, ceftazidime, amikacin, and cefepime were lower (with χ² value respectively 10.1, 16.1, 9.3, 33.8, P values all below 0.01). The antimicrobial resistance to all examined drug between exo U-/exo S+ type and exo U+/exo S- type isolates was close (with χ² values from 0.08 to 2.04, P values all above 0.05). Patients detected with exo U+/exo S- positive PA isolated from sputum were significantly associated with PA infection, and they usually had history of tracheal intubation, ICU hospitalization, and combined use of drugs for anti-infection treatment. Patients detected with exo U-/exo S+ positive PA isolated from sputum were significantly associated with PA colonization, which had basic lung disease and better outcome than the former infection type.</p><p><b>CONCLUSIONS</b>The TTSS exists in most clinical isolates of PA. Detection of exo U or exo S of PA isolated from sputum is helpful for the analysis of clinical features and outcome of patients.</p>

Clinical evaluation of the application of gene chip for identifying pathogens in blood cultures / 南方医科大学学报

<p><b>OBJECTIVE</b>To explore the feasibility of using gene chip method to identify pathogens in blood cultures.</p><p><b>METHODS</b>Clinical blood samples were obtained and cultured using an automated blood culture system. A gene chip diagnostic kit was used to detect the pathogenic bacteria in these blood cultures following the procedures of target gene extraction and amplification, hybridization and result analysis. The conventional method was also used to isolate and identify the bacteria from the clinical blood cultures, and the results of the two methods were compared.</p><p><b>RESULTS</b>In the 86 clinical blood samples, 74 were positive and 12 negative according to the conventional method, while 48 were positive and 38 negative as found by the gene chip method, showing significant differences in the results (P<0.05). The two methods only had a concordance rate of 69.77%.</p><p><b>CONCLUSION</b>The gene chip diagnostic kit has low concordance rate with the conventional method for detecting pathogens in clinical blood cultures and awaits further improvement.</p>

Frequencies of autoantibodies specific for primary biliary cirrhosis in a general adult population group / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To investigate the frequencies of primary biliary cirrhosis (PBC)-specific autoantibodies, including antimitochondrial autoantibodies (AMA) M2, anti-gp210 and anti-Sp100, and to assess their point prevalence rates in a general adult population group in Guangzhou.</p><p><b>METHODS</b>Eight thousand one hundred twenty-six adults (mean age 43.5+/-14.6 years, range 18 to 83 years; 4248 males and 3878 females) were enrolled for this study. AMA and anti-nuclear antibodies (ANA) were screened by indirect immunofluorescence test and AMA-M2, anti-gp210 and anti-sp100 were further detected using ELISA or immunoblotting assay. PBC diagnosis was made according to criteria recommended by AASLD in 2000.</p><p><b>RESULTS</b>Of the 8126 adults tested, 35 (0.43%) and 79 (0.97%) were found to be positive for AMA and ANA. The positivity for both of AMA and ANA increased with aging. Twenty-two cases were positive for PBC-specific autoantibodies. Frequencies for AMA-M2, anti-sp100 and anti-gp210 in the general adult population were 0.23%, 0.05% and 0.04% respectively and their frequency reached 0.62% in women over 40 years. A woman among the 22 cases who was PBC-specific autoantibody positive was finally diagnosed as a PBC patient.</p><p><b>CONCLUSION</b>Our data indicates that PBC specific autoantibodies exist in the general adult population at very low frequencies and the point prevalence rate of PBC in adults in Guangzhou is not less than that of other areas.</p>