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1.
Respiratory tract infection is a major cause of hospitalization in children. Although most such infections are viral in origin, it is difficult to differentiate bacterial and viral infections, as the clinical symptoms are similar. Multiplex polymerase chain reaction (PCR) methods allow testing for multiple pathogens simultaneously and are, therefore, gaining interest. This prospective case-control study was conducted from October 2013 to February 2014. Nasopharyngeal (NP) and oropharyngeal (throat) swabs were obtained from children admitted with severe acute respiratory infection (SARI) at a tertiary hospital. A control group of 40 asymptomatic children was included. Testing for 16 viruses was done by real-time multiplex PCR. Multiplex PCR detected a viral pathogen in 159/177 (89.9 %) patients admitted with SARI. There was a high rate of co-infection (46.9 %). Dual detections were observed in 64 (36.2 %), triple detections in 17 (9.6 %), and quadruple detections in 2 (1.1 %) of 177 samples. Seventy-eight patients required intensive care unit (ICU) admission, of whom 28 (35.8 %) had co-infection with multiple viruses. AdV, HBoV, HRV, HEV, and HCoV-OC43 were also detected among asymptomatic children. This study confirms the high rate of detection of viral nucleic acids by multiplex PCR among hospitalized children admitted with SARI, as well as the high rate of co-detection of multiple viruses. AdV, HBoV, HRV, HEV, and HCoV-OC43 were also detected in asymptomatic children, resulting in challenges in clinical interpretation. Studies are required to provide quantitative conclusions that will facilitate clinical interpretation and application of the results in the clinical setting.  相似文献   

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Viral respiratory tract infections in lung transplant recipients may be severe. During three consecutive winter-spring seasons, 49 symptomatic lung transplant recipients with suspected respiratory viral infection, and 26 asymptomatic patients were investigated for presence of respiratory viruses either in 56 nasopharyngeal aspirate or 72 bronchoalveolar lavage samples taken at different times after transplantation. On the whole, 1 asymptomatic (3.4%) and 28 symptomatic (57.1%) patients were positive for human metapneumovirus (hMPV, 4 patients), influenza virus A (3 patients), and B (2 patients), respiratory syncytial virus (2 patients), human coronavirus (2 patients), human parainfluenza virus (2 patients), rhinovirus (5 patients), while 4 patients were coinfected by 2 respiratory viruses, and 5 were infected sequentially by 2 or more respiratory viruses. In bronchoalveolar lavage samples, hMPV predominated by far over the other viruses, being responsible for 60% of positive specimens, whereas other viruses were present in nasopharyngeal aspirates at a comparable rate. RT-PCR (detecting 43 positive samples/128 examined) was largely superior to monoclonal antibodies (detecting 17 positive samples only). In addition, HCMV was detected in association with a respiratory virus in 4/18 HCMV-positive patients, and was found at a high concentration (>10(5) DNA copies/ml) in 3/16 (18.7%) patients with HCMV-positive bronchoalveolar lavage samples and pneumonia. Coinfections and sequential infections by HCMV and respiratory viruses were significantly more frequent in patients with acute rejection and steroid treatment. In conclusion: (i) about 50% of respiratory tract infections of lung transplant recipients were associated with one or more respiratory viruses; (ii) hMPV largely predominates in bronchoalveolar lavage of symptomatic lung transplant recipients, thus suggesting a causative role in lower respiratory tract infections; (iii) RT-PCR appears to be the method of choice for detection of respiratory viruses in lung transplant recipients, (iv) a high HCMV load in bronchoalveolar lavage is a risk factor for viral pneumonia, suggesting some measure of intervention for the control of viral infection.  相似文献   

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The MultiCode-PLx system (EraGen Biosciences, Inc., Madison, WI) for the detection of respiratory viruses uses an expanded genetic alphabet, multiplex PCR chemistry, and microsphere flow cytometry to rapidly detect and specifically identify 17 different respiratory viruses directly in clinical specimens. The MultiCode-PLx system was tested in parallel with direct fluorescent-antibody (DFA) staining and rapid shell vial culture (R-mix cells; Diagnostic Hybrids, Inc. Athens, OH) with 354 respiratory specimens from adult patients that were submitted to the clinical virology laboratory at the Emory University Hospital. Single-target PCRs were performed with retained samples to confirm the positive results obtained with the MultiCode-PLx system for viruses not covered by DFA and R-mix culture (metapneumovirus, coronaviruses [CoV], parainfluenza viruses 4a and 4b, and rhinoviruses) and to resolve any discrepancies between the DFA and R-mix culture and the MultiCode-PLx results for viruses common to both systems. Respiratory viruses were detected in 77 (21.8%) and 116 (32.7%) specimens by DFA and R-mix culture and with the MultiCode-PLx system, respectively. Among the viruses common to both systems, the MultiCode-PLx system detected significantly more influenza A viruses (P = 0.0026). An additional increased diagnostic yield with the MultiCode-PLx system resulted from the detection of human metapneumovirus (HMPV) in 9 specimens, human CoV (HCoV) in 3 specimens, and human rhinovirus (HRV) in 16 specimens. Also, two mixed viral infections were detected by the MultiCode-PLx system (HCoV OC43 and HRV infections and HMPV and HRV infections), but none were detected by DFA and R-mix culture. Single-target PCRs verified the results obtained with the MultiCode-PLx system for 73 of 81 (90.1%) specimens that had discordant results or that were not covered by DFA and R-mix culture. The MultiCode-PLx system provides clinical laboratories with a practical, rapid, and sensitive means for the massively multiplexed molecular detection of common respiratory viruses.  相似文献   

5.
BackgroundNucleic acid amplification techniques have improved the diagnostic possibilities in respiratory tract infections, although their clinical applicability is not yet fully defined. We have evaluated a multiplex real-time PCR method for the detection of 13 respiratory viruses and 2 bacteria (Mycoplasma and Chlamydophila) in a clinical setting.ObjectivesThe aim of the present study was to evaluate the diagnostic performance and clinical use of a novel multiplex PCR method in adults with community-acquired respiratory viral infection, and the impact of duration of symptoms on detection rates.Study designNasopharyngeal swab samples were prospectively collected from 209 adult outpatients with respiratory infections and 100 asymptomatic controls.ResultsAn infectious agent was identified in 43% of samples from patients and 2% of asymptomatic controls. The detection rate was significantly higher in samples from patients with a duration of symptoms of 6 days or less (51%) than in samples from patients with a duration of symptoms of 7 days or more (30%, p < 0.01). For human corona viruses, and influenza virus A and B there was a correlation between the amount of virus in each patient sample as measured Ct values and duration of symptoms.ConclusionsDuration of symptoms significantly affects the detection rate of respiratory pathogens by multiplex real-time PCR in nasopharyngeal swab samples from adult patients with respiratory infections. Our finding should be taken into account when using these tests in clinical practise.  相似文献   

6.
Adenoviruses have been recognized as important pathogens in immunocompromised hosts. Particularly in pediatric allogeneic stem cell transplant recipients, the morbidity of the patients and mortality in those patients with disseminated infections have been found to increase over the last few years. Severe infections are predominantly but not exclusively caused by subgroup C adenoviruses. A multiplex real-time PCR assay using molecular beacons as probes was developed to enable monitoring of adenovirus DNA in those patients with simultaneous identification of subgroups. An internal control was coamplified in the multiplex PCR to check for the DNA isolation procedure as well as the presence of inhibitors in the clinical samples. The assay has been applied retrospectively in patient groups with different clinical outcomes of infection. In fatal cases, significantly higher adenovirus loads developed, exceeding even 10(11) copies/ml of serum or plasma. Patients with viral loads over 10(6) copies/ml appear to have an increased risk for fatal complications. This quantitative real-time PCR assay has been prospectively used clinically since 2002 to study the course of adenovirus infection. In addition, the assay provides objective start and end points of therapeutic interventions, including the clinically important evaluation of antiviral drugs.  相似文献   

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BACKGROUND: Respiratory viruses cause severe infections in lung transplant recipients, which require rapid and accurate diagnosis for appropriate management. OBJECTIVES: To evaluate the added benefit of a multiplex PCR for respiratory viruses (influenza [FLU] A and B, respiratory syncytial virus [RSV] A and B and parainfluenza virus [PIV] 1, 2, and 3) complementing rapid respiratory viral culture (RRV) and FLU-A antigen detection (EIA) in this transplant population. RESULTS: Over 6 months, 116 nasal washes and bronchoalveolar lavages, obtained from 72 lung transplant recipients with symptoms of upper or lower respiratory tract infections, were tested in real time by RRV and FLU-A EIA, and batched frozen by PCR. One or more methods recognized a respiratory virus in 31 (27%) specimens, including 15 FLU-A, nine RSV and seven PIV. PCR identified 26 of 31 positive samples demonstrating a sensitivity of 84%, higher than RRV (67%) or EIA (54%). PCR, RRV and EIA detected 60, 80 and 54%, respectively, FLU-A samples. PCR and RRV were equivalent for RSV-A, PIV-2 and 3, but PCR found a significantly higher number of RSV-B and PIV-1. CONCLUSIONS: These data indicate that routine use of PCR will enhance the number and speed with which viral respiratory tract infections are diagnosed in lung transplant recipients.  相似文献   

9.
BackgroundThe prevalence of respiratory viruses in adults is largely underexplored, as most studies focus on children. Additionally, in severely ill or immunocompromised adults, where respiratory infections are mostly attributed to bacteria and fungi; respiratory viruses can lead to severe complications.ObjectivesTo evaluate the epidemiology of respiratory viruses in bronchoalveolar lavage fluid (BAL) specimens from patients with lower respiratory tract disease. The study population consisted of different groups including immunocompetent patients (control patients), solid organ transplant recipients, patients with haematological malignancies and other immunocompromised adults.Study designA total of 134 BAL fluid specimens collected during 2009–2011 were retrospectively assessed with the new commercial multiplex real-time PCR FTD Respiratory 21 Plus®, targeting 18 different viruses and 2 atypical bacterial pathogens.ResultsViral or atypical bacterial pathogens were detected in 29.1% of BAL fluid specimens. Coronaviruses were most prevalent (13.4%), followed by rhinoviruses (5.2%), RSV (4.5%) and bocaviruses (3.7%). Comparing the total number of viruses detected, a statistically significant difference was observed between the control group and patients with haematological malignancies (27.5% vs. 57.1%, p < 0.05).ConclusionIn conclusion, our study highlights the high prevalence of respiratory viruses in BAL fluid specimens from adult patients with lower respiratory tract disease. The methods to be used should be sensitive and cover a wide range of potential pathogens. The specific patient population can also influence the detection rates of respiratory viruses.  相似文献   

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We developed a multiplex real-time PCR assay using 6-carboxyfluorescein, 6-carboxy-4',5'-dichloro-2',7'-dimethoxyfluorescein, and carbocyanine 5-labeled probes to simultaneously quantify Epstein-Barr virus (EBV), cytomegalovirus (CMV), and human herpesvirus 6 (HHV-6) DNA. When previously tested and stored DNA samples were examined, results of the multiplex real-time PCR assay were as sensitive and specific as those of a single real-time PCR assay. The multiplex assay was used to quantify the EBV, CMV, and HHV-6 DNA in 46 transplant recipients. A total of 303 whole-blood and plasma specimens were collected and analyzed. According to the results of the multiplex assay, the detection rates for viral DNA in whole blood and plasma were 23.8% and 5.9% for EBV, 11.2% and 5.3% for CMV, and 12.5% and 2.0% for HHV-6, respectively. All forms of viral DNA were detected more frequently in whole blood than in plasma. During the symptomatic period, EBV DNA was detected in all whole-blood specimens but not in all plasma specimens. Furthermore, the EBV DNA load in whole blood was higher during the symptomatic period than during the asymptomatic period, whereas the EBV DNA load in plasma was similar for both periods. These results demonstrate that whole blood is more suitable for the quantification of EBV DNA in transplant patients. However, a cutoff value with clinical relevance still needs to be determined.  相似文献   

12.
A multiplex real-time PCR assay was developed with a LightCycler instrument for detection of influenza viruses A and B and the human respiratory syncytial virus (HRSV). Detection of each viral product and of an internal control was based on determination of specific melting temperatures by the LightCycler software. The lower limit of detection in the multiplex PCR assay was found to be 50 copies for each viral target. In an evaluation of nasopharyngeal samples collected from hospitalized children (ages, 0 to 3 years) with acute respiratory tract infections during the winter of 2001 to 2002, a viral pathogen was detected by the multiplex PCR test in 139 (66.8%) of 208 cases, including 45 (21.6%) influenza A virus infections, no (0%) influenza B virus infections, 106 (51%) HRSV infections, and 12 (5.8%) coinfections. The multiplex PCR test was compared to rapid antigen detection assays for influenza viruses A and B (Directigen; Becton Dickinson, Sparks, Md.) and HRSV (RSV TestPack; Abbott Laboratories, Abbott Park, Ill.) in 172 and 204 samples, respectively. After resolution of discrepant test results by use of additional PCR assays targeting other viral genes, the sensitivity (Se) and specificity (Sp) of the multiplex PCR assay for influenza A virus were 100 and 97.7% compared to 43.6 and 98.5% for the antigenic test. Similarly, the Se and Sp of the multiplex PCR assay for HRSV were 94.5 and 98.9% compared to 81.6 and 94.7% for the antigenic test. In conclusion, our multiplex real-time PCR assay combines both rapidity and sensitivity for detecting the most important respiratory viral pathogens in children.  相似文献   

13.
Respiratory tract infections (RTIs) are a leading cause of mortality and morbidity. Seasonality has been reported for many viruses, including influenza virus, respiratory syncytial virus (RSV), and the recently described human metapneumovirus (hMPV). We hypothesize that the availability of rapid, multiplex PCR diagnostics will provide better clinical care and new insights into the etiology and clinical spectrum of RTIs. We conducted a retrospective analysis of the incidence of respiratory pathogens at a 500-bed adult and 154-bed pediatric hospital tertiary care center. A total of 939 specimens from patients with an age range of 5 days to 91 years (median, 2 years) were tested by a multiplex respiratory pathogen PCR from November 14, 2011 to November 13, 2012. Sixty-five percent of specimens were positive for at least one pathogen. As the age of the patient increased, the positivity rate for the PCR decreased proportionately. Rhinoviruses/enteroviruses (Rhino/Entero) were the most prevalent (34.3 %) followed by RSV (19.2 %) and hMPV (6.2 %). Twelve percent of the positive samples were positive for multiple analytes, with Rhino/Entero and RSV being the most common combination. The peak months were September and May for Rhino/Entero infections, January for RSV and February for coronavirus. hMPV peaked 2 months after RSV, as has been observed recently in other studies. Multiplex PCR provides rapid diagnostic information that can be used to make knowledgeable clinical decisions and potentially reduce the use of antibiotics. Active respiratory PCR surveillance could also predict seasonal respiratory epidemics to allow for adequate planning of additional infection control measures.  相似文献   

14.
Since influenza viruses can cause severe illness, timely diagnosis is important for an adequate intervention. The available rapid detection methods either lack sensitivity or require complex laboratory manipulation. This study describes a rapid, sensitive detection method that can be easily applied to routine diagnosis. This method simultaneously detects influenza viruses A and B in specimens of patients with respiratory infections using a TaqMan-based real-time PCR assay. Primers and probes were selected from highly conserved regions of the matrix protein gene of influenza virus A and the hemagglutinin gene segment of influenza virus B. The applicability of this multiplex PCR was evaluated with 27 influenza virus A and 9 influenza virus B reference strains and isolates. In addition, the specificity of the assay was assessed using eight reference strains of other respiratory viruses (parainfluenza viruses 1 to 3, respiratory syncytial virus Long strain, rhinoviruses 1A and 14, and coronaviruses OC43 and 229E) and 30 combined nose and throat swabs from asymptomatic subjects. Electron microscopy-counted stocks of influenza viruses A and B were used to develop a quantitative PCR format. Thirteen copies of viral RNA were detected for influenza virus A, and 11 copies were detected for influenza virus B, equaling 0.02 and 0.006 50% tissue culture infective doses, respectively. The diagnostic efficacy of the multiplex TaqMan-based PCR was determined by testing 98 clinical samples. This real-time PCR technique was found to be more sensitive than the combination of conventional viral culturing and shell vial culturing.  相似文献   

15.
We tested the hypothesis that the results of real-time polymerase chain reaction (PCR) analyses for respiratory viruses would reduce antibiotic treatment and length of stay in elderly patients hospitalized with respiratory infections. Within 24 h of hospital admission, a total of 922 patients aged ≥60 years were interviewed for symptoms of ongoing respiratory tract infection. Symptomatic patients were swabbed for oropharyngeal/nasopharyngeal presence of viral pathogens immediately by members of the study group. During a 2-month period, non-symptomatic volunteers among interviewed patients were swabbed as well (controls). Oropharyngeal/nasopharyngeal swabs were analyzed with real-time PCR for nine common respiratory viruses. A total of 147 out of 173 symptomatic patients and 56 non-symptomatic patients (controls) agreed to participate in the study. The patients were allocated to three cohorts: (1) symptomatic and PCR-positive (S/PCR+), (2) symptomatic and PCR-negative (S/PCR?), or (3) non-symptomatic and PCR-negative (control). There were no non-symptomatic patients with a positive PCR result. A non-significant difference in the frequency of empiric antibiotic administration was found when comparing the S/PCR+ to the S/PCR? cohort; 16/19 (84 %) vs. 99/128 (77 %) (χ2?=?0.49). Antibiotic treatment was withdrawn in only two patients in the S/PCR+ cohort after receiving a positive viral diagnosis. The length of stay did not significantly differ between the S/PCR+ and the S/PCR? groups. We conclude that, at least in our general hospital setting, access to early viral diagnosis by real-time PCR had little impact on the antimicrobial treatment or length of hospitalization of elderly patients.  相似文献   

16.
Respiratory virus infections cause significant morbidity and mortality in immunocompromised patients. Timely diagnosis is needed to provide optimal clinical care. Diagnostic tests routinely available at most institutions are limited by poor sensitivity and a slow turnaround time. We collected 90 respiratory samples from 87 immunocompromised patients (56 bronchoalveolar lavage and 34 nasopharyngeal aspirate samples) in order to compare the performance of routine respiratory virus testing available at our institution to the FilmArray respiratory panel assay, a novel diagnostic tool which utilizes multiplex PCR to test for 21 respiratory pathogens with a 1-h turnaround time. Samples with discordant results and 13 samples with concordant results underwent further verification testing by laboratory-developed real-time PCR. The FilmArray assay identified viral pathogens in more samples than did clinical testing (30/90 versus 16/90; McNemar P = 0.001). Most of the additional viral pathogens identified by the FilmArray respiratory panel assay that were confirmed by verification testing were pathogens not assessed by routine clinical tests, including rhinovirus/enterovirus, human metapneumovirus, and coronavirus. The FilmArray respiratory panel assay allowed for increased identification of respiratory viral pathogens in this cohort of immunocompromised patients.  相似文献   

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SUMMARY: Clinical laboratories historically diagnose seven or eight respiratory virus infections using a combination of techniques including enzyme immunoassay, direct fluorescent antibody staining, cell culture, and nucleic acid amplification tests. With the discovery of six new respiratory viruses since 2000, laboratories are faced with the challenge of detecting up to 19 different viruses that cause acute respiratory disease of both the upper and lower respiratory tracts. The application of nucleic acid amplification technology, particularly multiplex PCR coupled with fluidic or fixed microarrays, provides an important new approach for the detection of multiple respiratory viruses in a single test. These multiplex amplification tests provide a sensitive and comprehensive approach for the diagnosis of respiratory tract infections in individual hospitalized patients and the identification of the etiological agent in outbreaks of respiratory tract infection in the community. This review describes the molecular methods used to detect respiratory viruses and discusses the contribution that molecular testing, especially multiplex PCR, has made to our ability to detect respiratory viruses and to increase our understanding of the roles of various viral agents in acute respiratory disease.  相似文献   

18.
Human cytomegalovirus (HCMV) and human herpesvirus-6 (HHV-6) are two closely related viruses, which belong to the Herpesviridae family. Following primary infection, they are thought to persist for life as latent forms in mononuclear cells. HCMV and HHV-6 can cause considerable morbidity in immunocompromised individuals, such as transplant patients. A sensitive and specific LightCycler multiplex real-time PCR assay based on fluorescence energy transfer (known as FRET) was developed. This assay, by using two sets of hybridization probes specific for HHV-6 (A and B) and HCMV, can differentiate reliably and quantify simultaneously both viruses in order to diagnose reactivation processes. The assay was optimized and the lower limit of detection for both viruses was determined to be 10 viral genome copies per reaction. Both viruses were quantified in 83 peripheral blood mononuclear cells (PBMCs) and 87 polymorphonuclear leukocytes (PMNLs) collected from 32 transplant recipients. This multiplex real-time quantitative PCR was finally compared with two other quantitation and detection assays used daily in laboratory (PCR DIG detection and antigenemia for HCMV, TaqMan Assay for HHV-6). This technique can be useful for the differentiation and quantitation of HCMV and HHV-6 for monitoring transplant patients.  相似文献   

19.
Multiplex PCR and multiplex RT-PCR were developed to identify nine viruses in pigs with multiple infections. These viruses are: porcine circovirus type 2 (PCV2), suid herpesvirus 1, porcine parvovirus (PPV), porcine reproductive and respiratory syndrome virus (PRRSV), Japanese encephalitis virus, porcine rotavirus A (PoRV-A), porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV), and Getah virus. These methods were shown to be high specificity and sensitivity. In the clinical application, a total of 75 field samples were examined by our methods and previously reported methods for PCV2, PRRSV, TGEV, and PEDV. As a result, the detection rates of our multiplex PCR and multiplex RT-PCR were higher than those of the previously reported methods. Furthermore, it was confirmed that 24 PCV2 positive samples were co-infected with other viruses, 11 with PRRSV, 10 with PPV, 2 with PoRV-A, and 1 with TGEV by a combination of multiplex PCR and multiplex RT-PCR. PPV and PoRV-A were newly detected by multiplex PCR and multiplex RT-PCR. These results suggest that the combination of our multiplex PCR and multiplex RT-PCR is useful for rapid and accurate identification of nine major pathogenic viruses in pigs with multiple infections.  相似文献   

20.
The study aim was to investigate the prevalence and clinical relevance of viral findings by multiplex PCR from the nasopharynx of clinically septic patients during a winter season. During 11 weeks of the influenza epidemic period in January–March 2012, consecutive adult patients suspected to be septic (n = 432) were analyzed with cultures from blood and nasopharynx plus multiplex PCR for respiratory viruses on the nasopharyngeal specimen. The results were compared with those from microbiology analyses ordered as part of standard care. During the winter season, viral respiratory pathogens, mainly influenza A virus, human metapneumovirus, coronavirus, and respiratory syncytial virus were clinically underdiagnosed in 70% of patients positive by the multiplex PCR assay. During the first four weeks of the influenza epidemic, few tests for influenza were ordered by clinicians, indicating low awareness that the epidemic had started. Nasopharyngeal findings of Streptococcus pneumoniae and Haemophilus influenzae by culture correlated to pneumonia diagnosis, and in those patients laboratory signs of viral co-infections were common but rarely suspected by clinicians. The role of respiratory viral infections in patients presenting with a clinical picture of sepsis is underestimated. Specific antiviral treatment might be beneficial in some cases and may reduce spread in a hospital setting. Diagnosing viral infections may promote reduction of unnecessary antibiotic use. It can also be a tool for decisions concerning patient logistics, in order to minimize exposure of susceptible patients and personnel.  相似文献   

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