ABSTRACT
A bead-based liquid hybridization assay, Luminex(®) 100™, was used to identify four pathogenic bacteria, Bacillus anthracis, Clostridium botulinum, Francisella tularensis subsp. tularensis, and Yersinia pestis, and several close relatives. Hybridization between PCR-amplified target sequences and probe sequences (located within the 23S ribosomal RNA gene rrl and the genes related to the toxicity of each bacterium) was detected in single-probe or multiple-probe assays, depending on the organism. The lower limits of detection (LLDs) for the probes ranged from 0.1 to 10 ng. Sensitivity was improved using lambda exonuclease to digest the noncomplementary target strand. All contributors in 33 binary, ternary, and quaternary mixtures in which all components were present in a 1:1 ratio were identified with an 80% success rate. Twenty-eight binary mixtures in which the two components were combined in various ratios were further studied. All target sequences were detected, even when the minor component was overshadowed by a tenfold excess of the major component.
Subject(s)
Bacillus anthracis/genetics , Bacterial Typing Techniques/methods , Clostridium botulinum/genetics , Francisella tularensis/genetics , Microarray Analysis , Yersinia pestis/genetics , Microspheres , Polymerase Chain Reaction , RNA Probes , RNA, Ribosomal, 23S/geneticsABSTRACT
Objective To explore the diagnostic value of combined detection of the liquid array technology, interfer-on (IFN)-γand IFN-γ-inducible protein (IP)-10 in the rapid, accurate diagnosis and differential diagnosis of tuberculous pleural effusions. Methods Patients with transudative pleural effusions were divided into tuberculous pleural effusion group (n=52) and malignant pleural effusion group (n=38). The method of T-SPOT.TB was used to detect the number of effec-tor T cells sensitized to Mycobacterium tuberculosis and spot forming cells (SFCs). The liquid array technology was used to detect the level of IFN-γand IP-10. Logistic regression was used to analyze and compare the diagnostic value of the two-method combination. Results The diagnostic sensitivity, specificity and the area under the ROC curve (AUC) of T-SPOT. TB were 90.38%, 84.21%, and 0.938 (95%CI:0.867-0.978), respectively. The diagnostic sensitivity, specificity and AUC of combined detection of IFN-γand IP-10 were 98.08%, 97.37%, and 0.995 (95%CI:0.951-1.000), respectively. There was no significant difference in the diagnostic sensitivity and specificity between the two methods, and the diagnostic agreement for the two diagnostic methods was fine (Kappa=0.703). The difference of AUC between the methods was significantly differ-ent (Z=1.996, P<0.05). The method of combined detection of IFN-γand IP-10 showed the larger AUC (AUC=0.995). Con-clusion The combined diagnosis meets the clinical needs of rapid, accurate diagnosis and differential diagnosis for tuber-culous pleural effusion by simultaneously assaying the level of IFN-γand IP-10 using the liquid array technology.
