Evaluation of three analyte-specific reagents for detection and typing of herpes simplex virus in cerebrospinal fluid

Rapid-Onset Temporal Encephalitis With Negative Cerebrospinal Fluid Polymerase Chain Reaction Testing

Herpes simplex encephalitis is a rare disease presentation that is usually characterized by its temporal involvement and positive cerebrospinal fluid (CSF) polymerase chain reaction (PCR) for the herpes simplex virus (HSV). HSV PCR has a sensitivity of 96% and specificity of 99%. Even when the test is negative, if clinical suspicion is high, acyclovir therapy should be continued with a repeated PCR within a week. In this case, we report a 75-year-old female patient who presented with signs of hypertensive emergency with rapid deterioration to seizure-like activity on electroencephalogram (EEG) and signs of temporal encephalitis on magnetic resonance imaging (MRI). The patient did not respond to the initial regimen of antibiotics but did show significant clinical response to acyclovir though she had a negative CSF PCR for HSV ten days after the start of her neurological symptoms. In this case, we argue that alternative methods of diagnosis should be considered in cases of acute encephalitis. Our patient had negative PCR but her computerized tomography (CT), EEG, and MRI results pointed to temporal encephalitis caused by HSV.

A Fatal Case of Herpes Simplex Encephalitis with Two False-Negative Polymerase Chain Reactions

An 88-year-old man presented with a 1-month history of altered mental status and seizures. His electrographic and imaging findings were suggestive of herpes simplex encephalitis (HSE), for which he was empirically treated with acyclovir. He underwent two lumbar punctures 3 days apart; both cerebrospinal fluid analyses tested negative for herpes simplex virus (HSV) by polymerase chain reaction (PCR). These negative results and his continued deterioration after 9 days of acyclovir therapy prompted treatment with steroids for possible autoimmune encephalitis. Shortly after the change in management, the patient died from cardiac arrest. At autopsy, his brain showed both gross and microscopic evidence of encephalitis and was positive for HSV by immunohistochemistry. This fatal case of HSE emphasizes the limitations of HSV PCR and the importance of clinical suspicion in the diagnosis and management of this disease.

[Genital herpes and pregnancy: Serological and molecular diagnostic tools. Guidelines for clinical practice from the French College of Gynecologists and Obstetricians (CNGOF)]

OBJECTIVES

To describe serological and molecular tools available for genital and neonatal herpes, and their use in different clinical situations.

METHODS

Bibliographic investigations from MedLine database and consultation of international clinical practice guidelines.

RESULTS

Virological confirmation of genital herpes during pregnancy or neonatal herpes must rely on PCR (Professional consensus). HSV type-specific serology (IgG) will allow determining the immune status of a patient (in the absence of clinical lesions). However, there is currently no evidence to justify universal HSV serological testing during pregnancy (Professional consensus). In case of genital lesions in a pregnant woman that do not report any genital herpes before, it is recommended to perform a virological confirmation by PCR and HSV type-specific IgG in order to distinguish a true primary infection, a non-primary infection associated with first genital manifestation, from a recurrence (Grade C). HSV IgM is useless for diagnosis of genital herpes (Grade C). If a pregnant woman has personal history of genital herpes but no lesions, whatever the gestational age, it is not recommended to perform genital sampling nor serology (Professional consensus). In case of recurrence, if the lesion is characteristic of herpes, virological confirmation is not necessary (Professional Agreement). However, if the lesion is not characteristic, virological confirmation by PCR should be performed (Professional consensus). At birth, HSV PCR samples should be collected as soon as neonatal herpes is suspected (symptomatic neonate) (best before beginning antiviral treatment but must not delay the treatment), or after 24hours of life in case of asymptomatic neonate born to a mother with herpes lesions at delivery (Professional consensus). Clinical samples for virological confirmation should include at least blood and a peripheral location. In case of clinical manifestations of herpes in the neonate, first samples PCR positive, preterm birth, or maternal primary infection or non-primary infection associated with first genital manifestation at delivery, CSF should also be collected as well as samples of lesions in the neonate if present (Professional consensus). Sampling should be repeated in case of PCR negative but strong evidence of neonatal herpes (Professional consensus). HSV serology is useless for diagnosis of neonatal herpes (Grade C).

CONCLUSIONS

Virological confirmation for diagnosis of genital herpes during pregnancy or neonatal herpes must rely on PCR. PCR assays available in France are very reliable. Specific IgG are dedicated to restricted indications.

Type-specific detection of herpes simplex virus type 1 and type 2 using the cobas® HSV 1 and 2 test on the cobas® 4800 platform

INTRODUCTION

HSV-1 and HSV-2 are among the most common causes of sexually transmitted infections (stis) globally. these infections are strongly associated with increased risk of hiv acquisition and rare, but devastating, neonatal disease. available treatment options can reduce HSV transmission and improve quality of life. accurate diagnosis early in disease can improve patient management. Areas covered: This paper describes the clinical manifestations of HSV infection often used for clinical diagnostic purposes. The paper then describes the evolution of laboratory diagnostic assays. Serology, culture and molecular diagnostics are described since all are currently in use. The features and performance characteristics of the cobas 4800 HSV1 and HSV2 Test (cobas HSV) on the cobas 4800® system (cobas 4800) are described in detail. Expert commentary: Diagnosis of HSV has historically been unreliable or technically difficult, but the availability of molecular assays such as the cobas HSV test for detection and typing of herpes can improve our ability to correctly manage this disease. Utilization of tools such as the cobas HSV assay may help shorten the time to accurate diagnosis and treatment thus potentially reducing the risk of transmission and the global burden of HSV.

Multicenter Evaluation of Meridian Bioscience HSV 1&2 Molecular Assay for Detection of Herpes Simplex Virus 1 and 2 from Clinical Cutaneous and Mucocutaneous Specimens

Herpes simplex virus (HSV) causes acute and relapsing symptoms characterized by ulcerative lesions. Laboratory diagnosis of HSV in cutaneous or mucocutaneous lesions has historically been performed with the use of viral cell culture systems; however, these tests are laborious and suffer decreased sensitivity for advanced-stage lesions. The recent availability of FDA-cleared moderately complex assays has resulted in the increased use of molecular diagnostics for the routine detection of HSV in superficial swab specimens. We performed a clinical evaluation of the recently FDA-cleared illumigene HSV 1&2 loop-mediated isothermal amplification (LAMP) assay (Meridian Bioscience, Cincinnati OH) for the detection and differentiation of HSV-1 and HSV-2 in cutaneous and mucocutaneous swab specimens. A total of 1,153 clinical swab specimens were collected and tested at 7 different clinical centers. Each specimen was tested for the presence of HSV-1 and HSV-2 using the illumigene assay, and results were compared to those of the enzyme-linked virus-inducible system (ELVIS) as the reference method. Overall, the illumigene assay demonstrated a sensitivity and specificity of 94.8% and 95.5%, respectively, for the detection of HSV-1. Detection of HSV-2 was similar, with a sensitivity of 98.9% and a specificity of 95.5%. Discrepant analysis was performed using an alternative molecular test (AmpliVue HSV1+2 assay; Quidel Molecular, San Diego, CA) on 91/99 specimens that were recorded as false positive (FP) or false negative (FN) compared to the reference method. In total, 57/78 (73%) FP and 9/13 (69%) FN illumigene results were supported by the AmpliVue result. The illumigene HSV 1&2 assay demonstrated high sensitivity and specificity to detect and differentiate HSV in clinical specimens and identified 57 additional specimens that were positive for HSV compared to culture. The use of LAMP eliminates the need for the cycling of temperatures and provides results in less than 60 min, with approximately 2 min of hands-on time per specimen.

Development and clinical evaluation of a novel fully automated qualitative PCR assay for the diagnosis of anogenital herpes simplex virus infection

Molecular detection of viral infections has the potential to improve microbial diagnostics, particularly with the emergence of rapid automated systems. We describe the design of the IDbox fully automated cassette-based system for nucleic acid extraction and real-time PCR amplification and perform a clinical evaluation for the diagnosis of genital herpes simplex infections. At optimal cutoff values determined by receiver-operator curves, the IDbox showed sensitivities of 94.9% (95% confidence interval [CI] 84.9-98.7%) and 97.0% (95% CI 88.5-99.5%) and specificities of 96.7% (95% CI 91.2-98.9%) and 97.3% (95% CI 91.9-99.3%) relative to herpes simplex virus culture and PCR, respectively. We discuss relevant design characteristics and approaches used for each step of the analytical process to enhance assay sensitivity and provide accurate results in the presence of potential cross-reactive organisms and interfering substances.

Diagnosis of genital herpes simplex virus infection in the clinical laboratory

Since the type of herpes simplex virus (HSV) infection affects prognosis and subsequent counseling, type-specific testing to distinguish HSV-1 from HSV-2 is always recommended. Although PCR has been the diagnostic standard method for HSV infections of the central nervous system, until now viral culture has been the test of choice for HSV genital infection. However, HSV PCR, with its consistently and substantially higher rate of HSV detection, could replace viral culture as the gold standard for the diagnosis of genital herpes in people with active mucocutaneous lesions, regardless of anatomic location or viral type. Alternatively, antigen detection—an immunofluorescence test or enzyme immunoassay from samples from symptomatic patients--could be employed, but HSV type determination is of importance. Type-specific serology based on glycoprotein G should be used for detecting asymptomatic individuals but widespread screening for HSV antibodies is not recommended. In conclusion, rapid and accurate laboratory diagnosis of HSV is now become a necessity, given the difficulty in making the clinical diagnosis of HSV, the growing worldwide prevalence of genital herpes and the availability of effective antiviral therapy.

Comparison of two multiplexed PCR assays for the detection of HSV-1, HSV-2, and VZV with extracted and unextracted cutaneous and mucosal specimens

BACKGROUND

Several analyte specific reagents (ASRs) are available for the detection and differentiation of HSV-1, HSV-2, and VZV in clinical specimens. However, there is limited data on the test performance of these reagents used in multiplexed PCR assays.

OBJECTIVE

This study compared the performance of two multiplexed ASR sets for detection of HSV-1, HSV-2, and VZV in dermal specimens.

STUDY DESIGN

Two commercially available ASRs were combined to produce multiplexed PCR assays for simultaneous detection of HSV-1, HSV-2, and VZV. Seeded samples were used to determine the limit of detection (LOD) for each assay. Patient samples (n=156) were tested in duplicate and results for each method compared to the reference standard of culture. Both extracted and unextracted specimens were used in the study.

RESULTS

Both multiplexed PCR assays showed similar test performance, with minimal LOD differences observed. The LOD was 10(3) copies/mL for HSV-1 and HSV-2 using the Focus assay compared to 5×10(3) copies/mL and 2×10(4) copies/mL, respectively for the EraGen assay. Both assays showed equal performance for VZV with a LOD of 5×10(3) copies/mL. Analytical specificity testing showed no cross reactivity with other selected DNA viruses. Both assays showed similar performance when clinical samples were tested using both extracted and unextracted specimens.

CONCLUSION

Commercially available ASRs can be successfully multiplexed for the PCR detection of HSV-1, HSV-2, and VZV using dermal specimens. Either direct testing or nucleic acid extracted specimens can be used with similar performance in these assays.

Comparative clinical evaluation of the IsoAmp(®) HSV Assay with ELVIS(®) HSV culture/ID/typing test system for the detection of herpes simplex virus in genital and oral lesions

BACKGROUND

The novel IsoAmp(®) HSV Assay employs isothermal helicase-dependent nucleic acid amplification and a user-friendly disposable test device to achieve rapid (<1.5h), on-demand qualitative detection of herpes simplex virus (HSV) types 1 and 2 in oral and genital lesions.

OBJECTIVES

To compare performance of the IsoAmp(®) HSV Assay with the ELVIS(®) HSV ID/typing (shell-vial culture and DFA) test system for clinical specimens collected from oral and genital lesions in symptomatic patients.

STUDY DESIGN

A total of 994 specimens from male and female genital and oral lesions were obtained and evaluated at five study sites in the United States. Results from the IsoAmp(®) HSV Assay were compared to those from the ELVIS(®) system. Separate reproducibility studies were performed at 3 sites using a blinded and randomized study panel. Discrepant specimens were resolved by bidirectional sequencing analysis.

RESULTS

After discrepant analysis, overall agreement of IsoAmp(®) with ELVIS(®) was 98.8% with 37.0% overall prevalence (all study sites). Reproducibility rates were well within expectations.

CONCLUSION

The IsoAmp(®) HSV Assay showed excellent performance for clinical use for detection of HSV in genital and oral specimens. In contrast to ELVIS(®), IsoAmp(®) HSV offers excellent sensitivity plus rapid on-demand testing and simpler specimen preparation.

Herpes simplex encephalitis with two false-negative cerebrospinal fluid PCR tests and review of negative PCR results in the clinical setting

INTRODUCTION

Herpes simplex virus encephalitis (HSE) is an acute infection accompanied by significant morbidity and mortality with the diagnosis often made by cerebrospinal fluid (CSF) polymerase chain reaction (PCR) testing.

CASE PRESENTATION

We report a case of a healthy 35-year-old woman presenting with altered mental status. Due to suspicion of herpes encephalitis, a CSF PCR for herpes virus was sent for examination and acyclovir was started. The patient had an immediate response to acyclovir; however, when the PCR returned negative she was discharged without therapy. The altered mental status returned and she was started on acyclovir therapy and a second CSF PCR sample was sent and was again negative. MRI performed at initial hospitalization was negative, but a repeat MRI demonstrated bilateral temporal lobe involvement suggestive of herpes encephalitis. The patient was successfully treated for 21 days with acyclovir.

CONCLUSION

CSF PCR for herpes virus is highly sensitive and specific and remains the standard for diagnosing herpes encephalitis. Clinicians should be aware of the pitfalls of CSF PCR testing, specifically false-negative results. Although rare, these false negatives can result in premature termination of treatment.

A rapid and simple isothermal nucleic acid amplification test for detection of herpes simplex virus types 1 and 2

BACKGROUND

A simple and rapid IsoAmp HSV assay has been developed for qualitative detection of herpes simplex virus (HSV) types 1 and 2 from genital lesions. Sample preparation involved a simple dilution step and the diluted specimens were directly added to the device and amplified by isothermal helicase-dependent amplification (HDA). Amplification products were then detected by a DNA strip embedded in a disposable cassette without any instrument. The total test turn-around time is less than 1.5h from specimen processing to result reporting.

OBJECTIVES

To evaluate the analytical and clinical performance of the IsoAmp HSV assay as well as the robustness and reproducibility of the assay.

STUDY DESIGN

The analytical sensitivity of the IsoAmp HSV assay was determined using both HSV-1 and HSV-2. Clinical performance was evaluated using 135 frozen specimens collected from patients with suspected HSV infection in genital area.

RESULTS

The analytical sensitivity of the assays was 5.5 and 34.1 copies/reaction for HSV-1 and HSV-2 respectively with a 95% confidence interval. When the herpes viral culture was used as the reference standard, the clinical sensitivity and specificity of the IsoAmp HSV assay were 100.0% and 96.3% respectively. The inter-laboratory reproducibility achieved an overall 97.5% agreement by testing a total of 80 blinded HSV-1 samples among five laboratories.

CONCLUSION

Adequate analytical and clinical performance of the IsoAmp HSV assay was demonstrated. This assay is simple to perform and has acceptable inter-laboratory reproducibility.

Detection and quantification of hepatitis C virus (HCV) by MultiCode-RTx real-time PCR targeting the HCV 3' untranslated region

A prototype, real-time reverse-transcription PCR assay, based on MultiCode-RTx technology, quantifying hepatitis C virus (HCV) RNA by targeting the HCV 3' untranslated region demonstrated linearity over 7 logs, with a good correlation between the quantitative results of this assay and the results of two commercially available comparator assays for 466 clinical specimens comprising all six HCV genotypes.