Detection of Major Human Herpesviruses in Iranian Patients with Suspected Encephalitis Using Multiplex Polymerase Chain Reaction

BACKGROUND

The Herpesviridae family plays a significant etiological role in central nervous system viral infections during primary infection or reactivation from a latent form. Early detection is crucial because prescribing some antivirals can prevent severe side effects or life-threatening conditions.

METHODS

In this study, 251 CSF specimens were collected from patients with clinical suspicion of viral encephalitis in Pars Hospital, Tehran, Iran. DNA was extracted, and a multiplex PCR was designed to investigate the presence of herpes simplex virus-1, herpes simplex virus-2, varicella zoster virus, Epstein-Barr virus, and cytomegalovirus.

RESULTS

Overall, 59 cases of the 251 CSF samples were positive for multiplex PCR (23.5%). The most frequent positive findings were EBV and HSV, with a prevalence of 10.3% and 8.7% (5.5% HSV-1 and 3.1% HSV-2), respectively. Four co-infections were also seen in this study.

CONCLUSIONS

This multiplex PCR assay detects simultaneously different herpesviruses in CSF samples of patients with suspected encephalitis in 2 rounds of PCR amplification; therefore, it is a reliable and cost-saving diagnostic method for evaluating patients infected with herpesvirus with neurological disorders.

Use of multiplex PCR based molecular diagnostics in diagnosis of suspected CNS infections in tertiary care setting-A retrospective study

OBJECTIVES

CNS infections like meningitis and encephalitis pose enormous healthcare challenges due to mortality, sequelae and socioeconomic burden. In tertiary setting, clinical, microbiological, cytological and radiological investigations are not distinctive enough for diagnosing microbial etiology. Molecular diagnostics is filling this gap. We evaluated the clinical impact of a commercially available multiplex molecular diagnostic system - SES for diagnosing suspected CNS infections.

PATIENTS AND METHODS

This study was conducted in our tertiary level Neurology ICU. 110 patients admitted during Nov-2010 to April-2014 were included. CSF samples of patients clinically suspected of having CNS infections were subjected to routine investigation in our laboratory and SES test at XCyton Diagnostics. We studied the impact of SES in diagnosis of CNS infections and its efficacy in helping therapeutic management.

RESULTS

SES showed detection rate of 42.18% and clinical specificity of 100%. It had 10 times higher detection rate than conventional tests. Streptococcus pneumoniae and Mycobacterium tuberculosis were two top bacterial pathogens. VZV was most detected viral pathogen. SES results elicited changes in therapy in both positive and negative cases. We observed superior patient outcomes as measured by GCS scale. 75% and 82.14% of the patients positive and negative on SES respectively, recovered fully.

CONCLUSION

Detecting causative organism and ruling out infectious etiology remain the most critical aspect for management and prognosis of patients with suspected CNS infections. In this study, we observed higher detection rate of pathogens, target specific escalation and evidence based de-escalation of antimicrobials using SES. Institution of appropriate therapy helped reduce unnecessary use of antimicrobials.

Retrospective analysis of multiplex polymerase chain reaction-based molecular diagnostics (SES) in 70 patients with suspected central nervous system infections: A single-center study

Background:

Central nervous system (CNS) infections present a grave health care challenge due to high morbidity and mortality. Clinical findings and conventional laboratory assessments are not sufficiently distinct for specific etiologic diagnosis. Identification of pathogens is a key to appropriate therapy.

Aim:

In this retrospective observational study, we evaluated the efficacy and clinical utility of syndrome evaluation system (SES) for diagnosing clinically suspected CNS infections.

Materials and Methods:

This retrospective analysis included inpatients in our tertiary level neurointensive care unit (NICU) and ward from February 2010 to December 2013. Cerebrospinal fluid (CSF) samples of 70 patients, clinically suspected of having CNS infections, were subjected to routine laboratory tests, culture, imaging, and SES. We analyzed the efficacy of SES in the diagnosis of CNS infections and its utility in therapeutic decision-making.

Results:

SES had a clinical sensitivity of 57.4% and clinical specificity of 95.6%. Streptococcus pneumoniae and Pseudomonas aeruginosa were the top two bacterial pathogens, whereas Herpes simplex virus (HSV) was the most common viral pathogen. Polymicrobial infections were detected in 32.14% of SES-positive cases. SES elicited a change in the management in 30% of the patients from initial empiric therapy. At discharge, 51 patients recovered fully while 11 patients had partial recovery. Three-month follow-up showed only six patients to have neurological deficits.

Conclusion:

In a tertiary care center, etiological microbial diagnosis is central to appropriate therapy and outcomes. Sensitive and accurate multiplex molecular diagnostics play a critical role in not only identifying the causative pathogen but also in helping clinicians to institute appropriate therapy, reduce overuse of antimicrobials, and ensure superior clinical outcomes.

Rapid virological diagnosis of central nervous system infections by use of a multiplex reverse transcription-PCR DNA microarray

Viruses are the main etiological cause of central nervous system (CNS) infections. A rapid molecular diagnosis is recommended to improve the therapeutic management of patients. The aim of this study was to evaluate the performances of a DNA microarray, the Clart Entherpex kit (Genomica, Coslada, Spain), allowing the rapid and simultaneous detection of 9 DNA and RNA neurotropic viruses: herpes simplex virus 1 (HSV-1), HSV-2, varicella-zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), human herpesvirus 6 (HHV-6), HHV-7, HHV-8, and the human enteroviruses (HEVs). This evaluation was performed with 28 samples from the European proficiency panels (Quality Control for Molecular Diagnostics [QCMD]; Glasgow, Scotland) and then with 78 cerebrospinal fluid (CSF) specimens. The majority of the QCMD results obtained by the DNA microarray were similar to those recorded by the overall QCMD participants. The main discrepant results were observed for low concentrations of HSV-2 and HEVs. From the clinical samples, the kit detected 27 of the 28 herpesvirus CNS infections and all of the 30 HEV-positive CSF samples. No false-positive result was observed among the 20 virus-negative CSF samples. The clinical sensitivity, specificity, and negative and positive predictive values of the assay were 98.3, 100, 95.2, and 100%, respectively, when the results were compared to those of commercially available PCR assays. Interestingly, HHV-7 was detected in 11 (37%) of the 30 HEV-positive CSF samples from children suffering from aseptic meningitis causing significantly longer lengths of stay at the hospital than infection with HEVs alone (2.4 versus 1.4 days; P = 0.038). In conclusion, this preliminary study showed that this DNA microarray could be a valuable molecular diagnostic tool for single and mixed DNA and RNA virus infections of the CNS.

Diagnostic microbiologique : du diagnostic par étiologie au diagnostic par syndrome

Objectifs

Depuis les dix dernières années, l’introduction de la biologie moléculaire et l’automatisation ont radicalement changé les pratiques dans les laboratoires de microbiologie clinique. L’amélioration de la communication entre les microbiologistes et les cliniciens ainsi que les évolutions technologiques telles que la standardisation et le développement de tests diagnostics plus rapides ont conduit à une réorganisation des laboratoires de microbiologie.

Méthodes

Jusqu’à présent la prescription des examens ciblait un diagnostic étiologique précis, actuellement l’évolution se fait vers le diagnostic par syndrome incluant un panel de tests regroupant les étiologies responsables d’un syndrome donné y compris les pathogènes émergents.

Résultats et conclusions

Dans cette revue, nous avons résumé les développements technologiques les plus récents en matière de diagnostic microbiologique adapté au diagnostic par syndrome incluant les stratégies de diagnostic exhaustif, les DNA microarray et les microarray antigéniques.

Challenges in designing a Taqman-based multiplex assay for the simultaneous detection of Herpes simplex virus types 1 and 2 and Varicella-zoster virus

To optimise molecular detection of herpesviruses an internally controlled multiplex Taqman-PCR for the detection of Herpes simplex virus 1 (HSV1), Herpes simplex virus 2 (HSV2) and Varicella-zoster virus (VZV) was developed. The selection of the dye combination working on the ABI 7700 cycler for this multiplex PCR revealed crosstalk phenomena between several combinations of reference dyes and reporter dyes. A final dye combination with CY5 as reference dye and FAM/JOE/TXR as reporter dyes was selected. The influence of the concentration of the internal positive control (IPC) concentration on the quantitative results of HSV1, HSV2 and VZV positive patient samples was analysed. The results indicate that high IPC concentrations are detrimental for the sensitivity of the multiplex assay and that the presence of the IPC molecule narrows the dynamic range of the duplex PCRs between any of the virus PCRs and the IPC-PCR. The optimised multiplex assay detecting HSV1, HSV2 and VZV using 10(3) IPC molecules showed a performance and sensitivity comparable to that of the individual assays.