Application comparison of VDRL and TRUST in syphilis laboratory diagnosis / 国际检验医学杂志

Objective To investigate the application of venereal disease research laboratory(VDRL) test and toluidine red unheated serum test(TRUST) in syphilis laboratory diagnosis.Methods Serum,plasma and cerebrospinal fluid (CSF) in syphilis patients and healthy controls were measured by VDRL and TRUST.Results The VDRL detection results in serum and CSF sepcimens were generally higher than the TRUST detection results by 1-2 titers,while in plasma specimen,the VDRL detection results were generally lower than the TRUST detection results by 1-2 titers than TRUST when using plasma specimen.In addition,the VDRL detection in normal control serum and plasma specimens all appeared different degrees of false positive,but in the detection of normal control CSF,the results of TRUST and VDRL were consistent.Conclusion TRUST is more suitable for serum and plasma specimens,and CSF is suitable for the CSF specimen,but not suitable for serum and plasma detection.

Risk factors for healthcare-associated infection in patients after extracorporeal membrane oxygenation procedure / 中国感染控制杂志

Objective To realize the incidence of healthcare-associated infection(HAI)in patients after receiving extracorporeal membrane oxygenation(ECMO)procedure,and to evaluate the related factors for HAI.Methods Clinical data of patients receiving ECMO from January 2003 to December 2012 were collected and analyzed retro-spectively.Results Of 43 patients receiving ECMO,15 (34.88% )developed 24 times(55.81% )of HAI. The main HAI site was lower respiratory tract(n= 12,50.00% ),followed by blood stream(n= 6,25.00% ),skin and soft tis-sue(n= 5,20.83% ).A total of 28 isolates of pathogens were detected,gram-negative bacilli were 19(67.86% )iso-lates,gram-positive cocci 7(25.00% ),and fungi 2(7.14% );pathogens were mainly isolated from specimens of sputum(n= 12,42.86% ),blood (n= 9,32.14% )and wound secretion(n= 6,21 .43% ). The incidence of postopera-tive HAI in ECMO patients was related with patients’age,duration of ECMO,complication,mechanical ventila-tion,tracheal intubation or tracheotomy,and indwelling urinary catheter.Conclusion HAI in patients receiving EC-MO is high,hospital should take corresponding prevention and control measures targeting to the related risk factors of infection,so as to reduce the incidence of HAI after the ECMO.

In vitro susceptibility to 6 antimicrobial agents and genotyping of clinical isolates of Chlamydia trachomatis / 中华皮肤科杂志

Objective To assess the vitro susceptibility to 6 antimicrobial agents and genotypes of clinical isolates of Chlamydia trachomatis (Ct) from Guangzhou region. Methods Ct was isolated from clinical specimens by using McCoy cell culture and subjected to propagation. The minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of 6 antimicrobial agents (clarithromycin, roxithromycin, azithromycin, doxycycline, tetracycline, ofloxacin) against Ct isolates were determined in McCoy cell culture. Nested PCR was performed to amplify the outer membrane protein 1 (omp1) VS1-2 gene followed by sequencing. Results Seventy-six Ct strains were isolated from 346 urogenital specimens, and 40 strains met the require ments for susceptibility testing after serial propagation. The MIC50/MIC90 of clarithromycin, azithromycin, roxi thromycin, doxycycline, tetracycline and ofloxacin were as follows: 0.008/0.032, 0.080/0.160, 0.125/0.500, 0.032/0.064, 0.250/0.500 and 0.500/1.000 mg/L. Seven genotypes were observed. The most prevalent geno types in decreasing order were E (14, 35%), J (10, 25%)and F (6, 15%). The MIC50 was consistent for azithromycin among the 7 genotypes, but varied by 1 - 4 folds for doxycycline, ofloxacin and roxithromycin. Conclusions Clarithromycin, doxycycline and azithromycin exhibit an excellent activity against Ct, and the activity of azithromycin is consistent among the 7 genotypes of Ct.

Rapid detection of pathogenic mycoplasmas in genitourinary tract using PCR-reverse dot blot hybridization / 中华皮肤科杂志

Objective To develop a PCR-mverse dot blot hybridization(RDB)assay to rapidly detect pathogenic mycoplasmas in genitourinary tract.Methods Universal primers were designed and applied to amplify the 16S rRNA gone of ureaplasma parvum(Up),ureaplasma urealyticum(Uu),Mycoplasma genitalium(Mg),Mycoplasma hominis(Mh)by using nestcd PCR.Specific nucleotide probes of Up,Uu,Mg and Mh Were constructed and immobilized onto nylon membranes.PCR products were denatured and hybridized、with specific oligonucleofide probes on nylon membrane.The sensitivity and specificity of the PCR-RDB assay were evaluated based.on the hybddizafion results.Also,PCR-RDB Was utilized to detect pathogenic mycoplasmas from 60 clinical samples.Results The four probes selectively hybridized with the PCR product of corresponding mycoplasmas,and no cross hybridization was observed.The detection limit of PCR-RDB Was one colony forming unit(CFU)of mycoplasma.Out of the 60 clinical samples、19were positive for mycoplasm,Mixed infections were found in three samples,including two coinfected with Up and Uu and one with Uu and Mg.Conclusion PCR-RDB is a rapid,specific and sensitive approach to the identification of pathogenic mycoplasmas in urogenital tract.

Detection and Genotyping of Treponema pallidum by a Nested PCR / 中华皮肤科杂志

Objective To develop a nested PCR for the detection of early syphilis and genotyping of Treponema pallidum (TP), and to investigate the distribution of genotypes of TP in Guangzhou. Methods Specimens were consecutively collected from genital ulcers of patients with suspected chancre during 2002-2004, and were detected by dark-field microscopy and nested PCR. The acidic repeat protein (arp) gene and the T. pallidum repeat (tpr) gene family were amplified with the positive specimens above. The number of repeats presented in the arp gene and the restriction fragment length polymorphism by Mse I in the tpr gene were analyzed by electrophoresis. The strains were genotyped according to Pillay's criteria. Results Out of 62 patients with suspected chancre, 33 cases (53.2%) were positive by dark-field microscopy and 54 cases (87.1%) by nested PCR. Of 47 TP-positive specimens genotyped by arp gene, 36 (76.6%) were type 14, while of 49 cases genotyped by tpr gene 39 (79.6%) were type d. By combining genotypes of arp and tpr genes, 7 genotypes were found, including 14d (31, 66.0%), 13d (5, 10.6%), 14b (4, 8.5%), 12b (3, 6.4%), 12d (2, 4.3%), 15d(l, 2.2%) and 14i (1, 2.2%). Conclusions Nested PCR shows a high sensitivity in early detection of TP. Genotype 14d seems the predominant type of TP in Guangzhou.