There has been increasing interest in standardized and quantitative Epstein-Barr virus (EBV) DNA testing for the management of EBV disease. We evaluated the performance of the Real-Q EBV Quantification Kit (BioSewoom, Korea) in whole blood (WB). Nucleic acid extraction and real-time PCR were performed by using the MagNA Pure 96 (Roche Diagnostics, Germany) and 7500 Fast real-time PCR system (Applied Biosystems, USA), respectively. Assay sensitivity, linearity, and conversion factor were determined by using the World Health Organization international standard diluted in EBV-negative WB. We used 81 WB clinical specimens to compare performance of the Real-Q EBV Quantification Kit and artus EBV RG PCR Kit (Qiagen, Germany). The limit of detection (LOD) and limit of quantification (LOQ) for the Real-Q kit were 453 and 750 IU/mL, respectively. The conversion factor from EBV genomic copies to IU was 0.62. The linear range of the assay was from 750 to 10⁶ IU/mL. Viral load values measured with the Real-Q assay were on average 0.54 log₁₀ copies/mL higher than those measured with the artus assay. The Real-Q assay offered good analytical performance for EBV DNA quantification in WB.
DNA, Viral/*blood/metabolism ; Epstein-Barr Virus Infections/diagnosis/virology ; Herpesvirus 4, Human/*genetics/isolation & purification ; Humans ; Limit of Detection ; Reagent Kits, Diagnostic ; Real-Time Polymerase Chain Reaction

BACKGROUNDAcute respiratory infection (ARI) is one of the most common infectious diseases in infants and young children globally. This study aimed to determine the virus profile in children with ARI presenting with different severities.

METHODSClinical specimens collected from children with ARI in Beijing from September 2010 to March 2011 were investigated for 18 respiratory viruses using an xTAG Respiratory Viral Panel Fast (RVP Fast) assay. The Pearson chi-square analysis was used to identify statistical significance.

RESULTSOf 270 cases from three groups of ARI patients, including Out-patients, In-patients and patients in the intensive care unit (ICU), viruses were detected in 176 (65.2%) specimens with the RVP Fast assay. The viral detection rate from the Out-patients group (50.0%) was significantly lower than that from the In-patients (71.1%) and ICU-patients (74.4%) groups. The virus distribution was different between the Out-patients group and the other hospitalized groups, while the virus detection rate and distribution characteristics were similar between the In-patients and ICU-patients groups. The co-infection rates of the Out-patients group, the In-patients group, and the ICU-patients group were 15.6%, 50.0% and 35.8%, respectively. In addition to respiratory syncytial virus (RSV) and adenovirus (ADV), human rhinovirus (HRV) was frequently detected from children with serious illnesses, followed by human metapneumovirus (hMPV), human bocavirus (HBoV) and coronaviruses. Parainfluenza virus 3 (PIV3) was detected in children with lower respiratory illness, but rarely from those with serious illnesses in the ICU-patient group.

CONCLUSIONIn addition to so-called common respiratory viruses, virus detection in children with ARI should include those thought to be uncommon respiratory viruses, especially when there are severe ARI-related clinical illnesses.

Antigens, Viral ; analysis ; Beijing ; Child ; Child, Preschool ; China ; DNA, Viral ; genetics ; Female ; Humans ; Infant ; Infant, Newborn ; Influenza A virus ; genetics ; pathogenicity ; Male ; RNA, Viral ; genetics ; Respiratory Tract Infections ; diagnosis ; virology ; Rhinovirus ; genetics ; pathogenicity

In order to facilitate the detection of newly emerging or rare viral infectious diseases, a negative-strand RNA virus-severe fever with thrombocytopenia syndrome bunyavirus, and a positive-strand RNA virus-dengue virus, were used to investigate RNA viral genome unspecific amplification by multiple displacement amplification technique from clinical samples. Series of 10-fold diluted purified viral RNA were utilized as analog samples with different pathogen loads, after a series of reactions were sequentially processed, single-strand cDNA, double-strand cDNA, double-strand cDNA treated with ligation without or with supplemental RNA were generated, then a Phi29 DNA polymerase depended isothermal amplification was employed, and finally the target gene copies were detected by real time PCR assays to evaluate the amplification efficiencies of various methods. The results showed that multiple displacement amplification effects of single-strand or double-strand cDNA templates were limited, while the fold increases of double-strand cDNA templates treated with ligation could be up to 6 X 10(3), even 2 X 10(5) when supplemental RNA existed, and better results were obtained when viral RNA loads were lower. A RNA viral genome amplification system using multiple displacement amplification technique was established in this study and effective amplification of RNA viral genome with low load was achieved, which could provide a tool to synthesize adequate viral genome for multiplex pathogens detection.
Bunyaviridae Infections ; diagnosis ; virology ; Cell Line ; DNA Ligases ; metabolism ; DNA, Complementary ; analysis ; genetics ; DNA-Directed DNA Polymerase ; metabolism ; Dengue ; diagnosis ; virology ; Dengue Virus ; genetics ; isolation & purification ; Genome, Viral ; genetics ; Humans ; Phlebovirus ; genetics ; isolation & purification ; RNA, Viral ; analysis ; genetics ; Reference Standards ; Reverse Transcriptase Polymerase Chain Reaction ; methods ; Viral Load

To establish a fluorescent quantitative PCR method (FQ-PCR) with TaqMan probe for simultaneous detection of polyomavirus (BKV) and cytomegalovirus (CMV) and to evaluate its clinical application in the renal transplantation recipients. The conservative sequences of BKV and CMV were targeted and amplified by nested PCR technique. The PCR products were cloned into the plasmids pcDNA3. 1(+). The recombinant plasmid containing target sequences of BKV and CMV were constructed as external standards. The TaqMan-based assay was optimized. For evaluating the assay, the sensitivity was determinated by diluted standard (5 X 103-10icopies/mL), and the specificity was verified by negative control and positive control, and the precision was assessed by intra-assay coefficient of variation (ICV) through detecting standard repeatedly (20 times). A total of 480 blood samples of renal transplantation recipients were used to detect BKV and CMV DNA simultaneously with FQ-PCR, and the concentrations of FK506 were measured by ELISA. The association of DNA copy and concentrations of FK506 was analyzed. The cloned target BKV and CMV DNA was confirmed by sequencing and analysis. The sensitivity of the FQ-PCR assay reached 5 X 103 copies/ml in detecting BKV or CMV DNA. Control DNA verified the assay specifically detecting target DNA. The precision of the assay to quantif target DNA copies was acceptable (Intra-assay CV was 3.44% for BKV and 2.23% for CMV; Inter-assay CV was 4. 98% for BKV and 3.76% for CMV;). Of 480 samples, 130 samples (27. 08%) were CMV DNA positive, significantly higher than the BKV DNA positive (13.33%, 64/480, P<0.05). The positive BKV or CMV DNA was found to be associated with high concentrations of FK506 (P<0. 05). In conclusion, the developed real-time PCR assay for detecting both CMV and BKV DNA simultaneously was s high sensitive, precise and time-effectiveand could be applied in the monitoring of the CMV and BKV infection in the renal transplantation recipients.
Adolescent ; Adult ; Aged ; Conserved Sequence ; Cytomegalovirus ; genetics ; isolation & purification ; Cytomegalovirus Infections ; diagnosis ; virology ; DNA, Viral ; blood ; Female ; Humans ; Immunosuppressive Agents ; blood ; Kidney Transplantation ; adverse effects ; Male ; Middle Aged ; Polyomavirus ; genetics ; isolation & purification ; Polyomavirus Infections ; diagnosis ; virology ; Real-Time Polymerase Chain Reaction ; methods ; Reproducibility of Results ; Sensitivity and Specificity ; Species Specificity ; Tacrolimus ; blood ; Time Factors ; Tumor Virus Infections ; diagnosis ; virology ; Viral Load ; Young Adult

OBJECTIVETo establish a rapid, sensitive and specific reverse transcription-loop-mediated isothermal amplification (RT-LAMP) assay for detecting human respiratory syncytial virus (RSV) in respiratory samples collected from children with acute respiratory infections.

METHODAccording to the conserved matrix gene sequences of respiratory syncytial virus subtypes A and B downloaded from GenBank, primers were designed and RT-LAMP assay was developed to detect RNA of RSV sensitivity of the RT-LAMP method was evaluated by using ten-fold serially diluted in vitro-transcribed matrix RNA fragments from RSV A and RSV B, respectively. Specificity of the RT-LAMP method was tested through cross-reaction with other RNA and DNA viruses. Then 5 RSV strains isolated from clinical specimens using tissue cultures were tested by RT-LAMP assay. A total of 101 nasopharyngeal aspirates from hospitalized patients with acute respiratory infections which had been tested by direct immunofluorescence assay (DFA), including 40 positive for RSV and 61 negative for RSV, were tested by RT-LAMP assay and by RT-nested PCR.

RESULTSensitivity analysis indicated that this RT-LAMP method was able to detect 1 copy/µl of RSV A and RSV B RNA, no amplification was shown in RT-LAMP with DNA or cDNA from other viruses in 60 min, revealed that the RT-LAMP assay is highly specific. Five RSV isolates confirmed as 4 RSV A and 1 RSV B previously were detected by RT-LAMP method as positive in 30 min. For those 101 specimens tested, 37 were RSV positive determined by RT-LAMP assay, as well as 35 RSV positive by RT-nested PCR. The total coincidence rate of RT-LAMP assay with DFA and RT-nested PCR in detecting RSV is 95.0%, 94.1% with Kappa value 0.895 and 0.871, respectively.

CONCLUSIONA new, sensitive, accurate and rapid method, RT-LAMP assay for detecting human respiratory syncytial viruses from nasopharyngeal aspirates was developed, which should be helpful in rapid detection of RSV from respiratory tract samples of children.

Acute Disease ; Child ; Child, Preschool ; DNA Primers ; Humans ; Infant ; Molecular Diagnostic Techniques ; Nasopharynx ; virology ; Nucleic Acid Amplification Techniques ; RNA, Viral ; isolation & purification ; Respiratory Syncytial Virus Infections ; diagnosis ; Respiratory Syncytial Virus, Human ; isolation & purification ; Reverse Transcriptase Polymerase Chain Reaction ; Sensitivity and Specificity

This study was aimed to establish a method for rapid detecting BK polyomavirus (BKV) and to investigate the feasibility and value used in leukemia patients undergoing hematopoietic stem cell transplantation. Primers were designed according to BKV gene sequence; the quantitative standards for BKV and a real-time fluorescent quantitative PCR for BKV were established. The BKV level in urine samples from 36 patients after hematopoietic stem cell transplantation were detected by established method. The results showed that the standard of reconstructed plasmid and real time fluorescent quantitative PCR method were successfully established, its good specificity, sensitivity and stability were confirmed by experiments. BKV was found in 55.56% of urine samples, and the BKV load in urine was 2.46 × 10(4) - 7.8 × 10(9) copy/ml. It is concluded that the establishment of real-time fluorescent quantitative PCR for BKV detection provides a method for early diagnosis of the patients with hemorrhagic cystitis after hematopoietic stem cell transplantation.
Adolescent ; Adult ; BK Virus ; isolation & purification ; Case-Control Studies ; Cystitis ; prevention & control ; virology ; DNA Primers ; DNA, Viral ; urine ; Female ; Hematopoietic Stem Cell Transplantation ; Hemorrhage ; prevention & control ; virology ; Humans ; Male ; Middle Aged ; Polymerase Chain Reaction ; methods ; Polyomavirus Infections ; diagnosis ; virology ; Viral Load ; Young Adult

A simple, rapid and sensitive colorimetric Reverse Transcription Loop Mediated Isothermal Amplification (RT-LAMP) method was established to detect human influenza A H1N1 virus. The method employed a set of six specially designed primers that recognized eight distinct sequences of the HA gene for amplification of nucleic acid under isothermal conditions at 65 degrees C for one and half hour. The amplification process of RT-LAMP was monitored by the addition of HNB (Hydroxy naphthol blue) dye prior to amplification. A positive reaction was indicated by a color change from violet to sky blue and confirmed by agarose electrophoresis. The specificity of the RT-LAMP assay was validated by cross-reaction with different swine and human influenza virus including human seasonal influenza A /H1N1 A /H3N2, influenza B and swine A /H1N1. The sensitivity of this assay was evaluated by serial dilutions of RNA molecules from in vitro transcription of human influenza A H1N1 HA gene. The assay was further evaluated with 30 clinical specimens with suspected pandemic influenza A H1N1 virus infection in parallel with RT-PCR detection and 26 clinical specimens with seasonal influenza virus infection. Our results showed that the RT-LAMP was able to achieve a sensitivity of 60 RNA copies with high specificity, and detection rate was comparable to that of the RT-PCR with the clinical samples of pandemic influenza A H1N1 infection. The RT-LAMP reaction with HNB could also be measured at 650nm in a microplate reader for quantitative analysis. Thus, we concluded that this colorimetric RT-LAMP assay had potential for the rapid screening of the human influenza A H1N1 virus infection in National influenza monitoring network laboratories and sentinel hospitals of provincial and municipal region in China.
Animals ; Colorimetry ; methods ; DNA Primers ; genetics ; Electrophoresis, Agar Gel ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; Humans ; Influenza A Virus, H1N1 Subtype ; genetics ; Influenza A Virus, H3N2 Subtype ; genetics ; Influenza, Human ; diagnosis ; virology ; Naphthalenesulfonates ; chemistry ; Nucleic Acid Amplification Techniques ; methods ; Orthomyxoviridae Infections ; diagnosis ; veterinary ; virology ; Reverse Transcriptase Polymerase Chain Reaction ; methods ; Sensitivity and Specificity ; Swine ; Swine Diseases ; diagnosis ; virology ; Temperature

Quantitative measurement of BK virus DNA (Q-BKDNA) has been used for the early diagnosis and monitoring of BK virus-associated nephropathy (BKVAN). This study was designed to determine the BKDNA cutoff for the diagnosis of BKVAN. Between June 2005 and February 2007, 64 renal transplant recipients taken renal biopsies due to renal impairment submitted plasma and urine for Q-BKDNA. Eight BKVAN patients (12.5%) had median viral loads of 6.0 log(10) copies/mL in plasma and 7.3 log(10) copies/mL in urine. Among 56 non-BKVAN patients, 45 were negative for Q-BKDNA; 4 were positive in plasma with a median viral load of 4.8 log(10) copies/ mL, and 10 were positive in urine with a median viral load of 4.8 log(10) copies/mL. Receiver operating characteristic curve analysis showed that a cutoff of 4.5 log(10) copies/mL in plasma and a cutoff of 5.9 log(10) copies/mL in urine had a sensitivity of 100% and a specificity of 96.4%, respectively. A combined cutoffs of 4 log(10) copies/ mL in plasma and 6 log(10) copies/mL in urine had better performance with a sensitivity of 100% and a specificity of 98.2% than each cutoff of urine or plasma. QBKDNA with the combined cutoffs could reliably diagnose BKVAN in renal transplant recipients.
Adolescent ; Adult ; BK Virus/*genetics ; Biopsy ; Calibration ; DNA, Viral/*genetics ; Female ; Humans ; Kidney Diseases/*virology ; Kidney Transplantation/*methods ; Male ; Middle Aged ; Polymerase Chain Reaction ; Polyomavirus Infections/diagnosis ; Treatment Outcome

BACKGROUND: We intended to evaluate the diagnostic usefulness of a multiplex reverse transcriptase- PCR (mRT-PCR) assay kit under dual priming oligonucleotide system (DPO) for the childhood acute respiratory tract infections. METHODS: Two hundred nasopharyngeal aspirates were taken from children < or = 5 yr old admitted due to acute respiratory infections in 2004. Direct fluorescent antibody (FA) assays were performed with fresh specimens; then, mRT-PCRs for the detection of 12 respiratory viruses (Seeplex RV detection kit, SeeGene, Seoul, Korea) were tested with frozen specimens. RESULTS: FA assays for five common respiratory viruses showed positive results in 66 patients (33.0%), while mRT-PCR detected causative viruses in 112 patients (56.0%), including 16 co-infected cases (8.0%). A total of 129 viruses were identified: respiratory syncytial virus A/B (38.0%/7.8%), influenza virus A/B (10.1%/5.4%), parainfluenza virus 1/2/3 (7.0%/3.1%/7.8%), coronavirus 229E or NL63 (6.2%), human metapneumovirus (4.7%), adenovirus (4.7%), rhinovirus (3.9%), and coronavirus OC43 (1.6%). CONCLUSIONS: DPO-based mRT-PCR was found as a sensitive tool for the detection of the viruses that cause childhood respiratory infections. Clinical significances of the agents detected by mRTPCR need further evaluations.
Child, Preschool ; DNA, Viral/analysis ; Fluorescent Antibody Technique, Direct ; Humans ; Infant ; Infant, Newborn ; Oligonucleotide Probes ; Reproducibility of Results ; Respiratory Tract Infections/*diagnosis/epidemiology/virology ; Reverse Transcriptase Polymerase Chain Reaction/*methods ; Virus Diseases/*diagnosis/epidemiology/virology ; Viruses/genetics/*isolation & purification

BACKGROUND: TT virus (TTV) infection is highly prevalent in general population and patients with hepatitis B virus (HBV) infection. The aim of the present study was to determine the distribution of the genotypes and genogroups of TTV in healthy and HBV-infected individuals in Korea. METHODS: Distribution of TTV genotypes and genogroups was investigated in the serum samples of 69 healthy and 59 HBV-infected individuals. PCR products of N22 region were genotyped by sequence analysis. TTV genogroups were determined by 5 different genogroup-specific PCR assays. RESULTS: Among the 20 sequenced isolates, 9 (45%) were genotype 2, 8 (40%) were genotype 1, 2 (10%) were genotype 3, and 1 (5%) was genotype 4. TTV genogroup 4 was found most frequently (52/128), followed by genogroup 3 (42/128), genogroup 1 (35/128), genogroup 5 (32/128), and genogroup 2 (1/128). Mixed infections with different genogroups were frequent. CONCLUSIONS: TTV genotype 2 and 1 are predominant genotypes. TTV genotype 3 was detected for the first time in Korea. TTV genogroups 4 and 3 were predominant genogroups. No significant difference was observed in the distribution of TTV genogroups between healthy and HBV-infected individuals.
Adult ; Amino Acid Sequence ; DNA Virus Infections/diagnosis/*virology ; Female ; Genotype ; Hepatitis B/*complications/diagnosis ; Humans ; Korea ; Male ; Middle Aged ; Molecular Sequence Data ; Phylogeny ; Polymerase Chain Reaction/methods ; Torque teno virus/classification/*genetics