Use of two real-time polymerase chain reactions (PCRs) to detect herpes simplex type 1 and 2-DNA after automated extraction of nucleic acid

Update on Herpes simplex keratitis management

Herpes simplex keratitis (HSK) is a common, potentially blinding condition characterised by recurrent infections of the cornea, seen by both general ophthalmologists and corneal specialists. Successful treatment of recurrences reduces disease duration, prevents progressive corneal scaring leading to vision loss and reduces risk of further recurrences. In this review we discuss the relative advantages of the diagnostic laboratory investigations including polymerase chain reaction, viral culture and fluorescence-based immunohistochemistry. We review treatment strategies in selected aspects of HSK and discuss the management options in cases not responding to treatment.

Two Cases of Late-Onset Anti-NMDAr Auto-Immune Encephalitis After Herpes Simplex Virus 1 Encephalitis

Context: Encephalitis due to herpes simplex virus 1 (HSV-1) was described as a potential trigger for the development of anti-N-methyl-D-aspartate receptor (NMDAr) auto-immune encephalitis (AIE) within a few days to a few weeks after the infection.

Methods: We assessed clinical, radiological, and biological diagnoses process, treatment response, and evolution.

Cases Reported: We report here cases of a 71-year-old man and a 57-year-old woman presenting anti-NMDAr AIE, respectively, 12 and 7 months after HSV-1 encephalitis. In both cases, the onset was brisk, and the symptoms were mainly neuropsychiatric (paranoid delirium, Capgras, and Cotard syndromes) and cognitive, with anterograde amnesia. Relapse of HSV encephalitis, epilepsy, and paraneoplastic neurologic syndromes were excluded. The clinical response to first-line treatments composed of intravenous immunoglobulins and high-dose corticosteroids was poor, whereas significant improvement was noticed after rituximab induction.

Conclusion: Post-herpetic anti-NMDAr AIE could arise several months after infection. Clinicians must be aware of this possibility, particularly if cognitive and/or psychiatric symptoms occurred after a remitting period. In our two cases, only rituximab was associated with clinical improvement.

Implementation and Evaluation of a Fully Automated Multiplex Real-Time PCR Assay on the BD Max Platform to Detect and Differentiate Herpesviridae from Cerebrospinal Fluids

A fully automated multiplex real-time PCR assay--including a sample process control and a plasmid based positive control--for the detection and differentiation of herpes simplex virus 1 (HSV1), herpes simplex virus 2 (HSV2) and varicella-zoster virus (VZV) from cerebrospinal fluids (CSF) was developed on the BD Max platform. Performance was compared to an established accredited multiplex real time PCR protocol utilizing the easyMAG and the LightCycler 480/II, both very common devices in viral molecular diagnostics. For clinical validation, 123 CSF specimens and 40 reference samples from national interlaboratory comparisons were examined with both methods, resulting in 97.6% and 100% concordance for CSF and reference samples, respectively. Utilizing the BD Max platform revealed sensitivities of 173 (CI 95%, 88-258) copies/ml for HSV1, 171 (CI 95%, 148-194) copies/ml for HSV2 and 84 (CI 95%, 5-163) copies/ml for VZV. Cross reactivity could be excluded by checking 25 common viral, bacterial and fungal human pathogens. Workflow analyses displayed shorter test duration as well as remarkable fewer and easier preparation steps with the potential to reduce error rates occurring when manually assessing patient samples. This protocol allows for a fully automated PCR assay on the BD Max platform for the simultaneously detection of herpesviridae from CSF specimens. Singular or multiple infections due to HSV1, HSV2 and VZV can reliably be differentiated with good sensitivities. Control parameters are included within the assay, thereby rendering its suitability for current quality management requirements.

Development and Validation of a Laboratory-Developed Multiplex Real-Time PCR Assay on the BD Max System for Detection of Herpes Simplex Virus and Varicella-Zoster Virus DNA in Various Clinical Specimens

A multiplex real-time PCR (quantitative PCR [qPCR]) assay detecting herpes simplex virus (HSV) and varicella-zoster virus (VZV) DNA together with an internal control was developed on the BD Max platform combining automated DNA extraction and an open amplification procedure. Its performance was compared to those of PCR assays routinely used in the laboratory, namely, a laboratory-developed test for HSV DNA on the LightCycler instrument and a test using a commercial master mix for VZV DNA on the ABI7500fast system. Using a pool of negative cerebrospinal fluid (CSF) samples spiked with either calibrated controls for HSV-1 and VZV or dilutions of a clinical strain that was previously quantified for HSV-2, the empirical limit of detection of the BD Max assay was 195.65, 91.80, and 414.07 copies/ml for HSV-1, HSV-2, and VZV, respectively. All the samples from HSV and VZV DNA quality control panels (Quality Control for Molecular Diagnostics [QCMD], 2013, Glasgow, United Kingdom) were correctly identified by the BD Max assay. From 180 clinical specimens of various origins, 2 CSF samples were found invalid by the BD Max assay due to the absence of detection of the internal control; a concordance of 100% was observed between the BD Max assay and the corresponding routine tests. The BD Max assay detected the PCR signal 3 to 4 cycles earlier than did the routine methods. With results available within 2 h on a wide range of specimens, this sensitive and fully automated PCR assay exhibited the qualities required for detecting simultaneously HSV and VZV DNA on a routine basis.

Rapid and direct detection of herpes simplex virus in cerebrospinal fluid by use of a commercial real-time PCR assay

Central nervous system infection due to herpes simplex virus (HSV) is a medical emergency and requires rapid diagnosis and initiation of therapy. In this study, we compared a routine real-time PCR assay for HSV types 1 (HSV-1) and 2 (HSV-2) to a recently FDA-approved direct PCR assay (Simplexa HSV-1/2 Direct; Focus Diagnostics, Cypress, CA) using cerebrospinal fluid samples (n = 100). The Simplexa HSV-1/2 assays demonstrated a combined sensitivity and specificity of 96.2% (50/52) and 97.9% (47/48), respectively. In addition, the Simplexa assay does not require nucleic acid extraction, and the results are available in 60 min.

Unusual clinical presentations of new-onset herpetic eye disease after ocular surgery

PURPOSE

To report five cases of new-onset herpetic eye disease with unusual presentation after ocular surgery.

METHODS

Herpetic eye disease was suspected in five cases, three after cataract surgery and two after lamellar corneal transplantation surgery. Of these, four cases presented within 2-6 weeks of surgery. The clinical presentation was in the form of an epithelial defect, suspected epithelial down growth, graft oedema with unexplained anterior chamber inflammation and graft-host interface infection. A swab for viral detection with real-time polymerase chain reaction was performed in all the described cases.

RESULTS

Herpes simplex disease was detected in all cases. All cases responded to the antiherpetic medications.

CONCLUSIONS

Our study shows that new-onset herpetic eye disease may occur after cataract surgery and lamellar corneal transplantation, and a high index of suspicion may be necessary for the diagnosis in such cases.

Diagnostics for Herpes Simplex Virus

Herpes simplex virus (HSV) is one of the most common, yet frequently overlooked, sexually transmitted infections. Since the type of HSV infection affects prognosis and subsequent counseling, type-specific testing to distinguish HSV-1 from HSV-2 is recommended. Although PCR has been the diagnostic standard 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, will likely 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, type-specific serologic tests based on glycoprotein G should be the test of choice to establish the diagnosis of HSV infection when no active lesion is present. Given the difficulty in making the clinical diagnosis of HSV, the growing worldwide prevalence of genital herpes and the availability of effective antiviral therapy, there is an increased demand for rapid, accurate laboratory diagnosis of patients with HSV.

Prospective evaluation of a new automated nucleic acid extraction system using routine clinical respiratory specimens

The aim of the study was to evaluate the MagNA Pure 96™ nucleic acid extraction system using clinical respiratory specimens for identifying viruses by qualitative real‐time PCR assays. Three extraction methods were tested, that is, the MagNA Pure LC™, the COBAS Ampliprep™, and the MagNA Pure 96™ with 10‐fold dilutions of an influenza A(H1N1)pdm09 sample. Two hundred thirty‐nine respiratory specimens, 35 throat swabs, 164 nasopharyngeal specimens, and 40 broncho‐alveolar fluids, were extracted with the MagNA Pure 96™ and the COBAS Ampliprep™ instruments. Forty COBAS Ampliprep™ positive samples were also tested. Real‐time PCRs were used to identify influenza A and influenza A(H1N1)pdm09, rhinovirus, enterovirus, adenovirus, varicella zoster virus, cytomegalovirus, and herpes simplex virus. Similar results were obtained on RNA extracted from dilutions of influenza A(H1N1)pdm09 with the three systems: the MagNA Pure LC™, the COBAS Ampliprep™, and the MagNA Pure 96™. Data from clinical respiratory specimens extracted with the MagNA Pure 96™ and COBAS Ampliprep™ instruments were in 98.5% in agreement (P < 0.0001) for influenza A and influenza A(H1N1)pdm09. Data for rhinovirus were in 97.3% agreement (P < 0.0001) and in 96.8% agreement for enterovirus. They were in 100% agreement for adenovirus. Data for cytomegalovirus and HSV1‐2 were in 95.2% agreement (P < 0.0001). The MagNA Pure 96™ instrument is easy‐to‐use, reliable, and has a high throughput for extracting total nucleic acid from respiratory specimens. These extracts are suitable for molecular diagnosis with any type of real‐time PCR assay. J. Med. Virol. 84:906–911, 2012. © 2012 Wiley Periodicals, Inc.

Clinical validation of a new triplex real-time polymerase chain reaction assay for the detection and discrimination of Herpes simplex virus types 1 and 2

A new triplex real-time polymerase chain reaction (PCR) assay for Herpes simplex virus (HSV) (artus HSV-1/2 TM PCR kit, QIAGEN) was evaluated. This assay simultaneously uses three differently labeled probes targeted to HSV-1 (FAM), HSV-2 (NED), and to the manufacturer's Internal Control (VIC). HSV-1/2 typing capability and quantitation accuracy were determined using HSV stocks and quality control panels. Performance in routine clinical testing was compared with a nested HSV-1/2 PCR assay. Dilution series and quality control panel testing revealed an approximately 10-fold higher HSV-2 sensitivity in real-time PCR compared with an in-house nested PCR assay. The sensitivity for HSV-1 was comparable in both assays. All HSV-positive proficiency panel samples (n = 21) and virus stocks were typed correctly as HSV-1 or HSV-2 using real-time PCR. Quantitation correlated well with reference values (HSV-1, r = 0.98; HSV-2, r = 0.88), and 95% detection limits were determined as 9.4 HSV-2 copies/reaction and 18 HSV-1 copies/reaction. Based on C(t) values, the mean intra-assay coefficient of variation was 1%, whereas the interassay coefficient of variations were 2.7% and 2.5% for HSV-1 and -2, respectively. Testing of 309 clinical samples resulted in 100% specificity and 97% sensitivity. In conclusion, the artus HSV-1/2 TM PCR kit represents an excellent tool for the detection and differentiation of HSV-1 and -2 in clinical samples.

Development of a novel internal control for a real-time PCR for HSV DNA types 1 and 2

BACKGROUND

Detection of herpes simplex virus types 1 and 2 DNA by polymerase chain reaction (PCR) is the method of choice in many laboratories due to improved sensitivity, specificity and turnaround times compared with culture and antigen detection. However, internal controls need to be employed to ensure that inhibitors in samples do not produce false negative results.

OBJECTIVE

We have developed an internal control for our routine diagnostic HSV 1 and 2 LightCycler PCR assay that has identical primer binding sites to the HSV target DNA but an internal sequence derived from plasmid DNA and detected by a different probe and fluorophore combination.

METHODS

Production of the internal control was achieved using a straightforward two-step PCR technique in which plasmid DNA was amplified with HSV-plasmid chimeric primers, followed by amplification of the resulting amplicons with HSV primers and purification for subsequent use.

RESULTS

Both the internal control and viral DNA were amplified in initial tests with 11 tissue-culture HSV 1 and 2 positives (22 in total), with little or no inhibition of the target sequences. A high level (98%) of concordant results were obtained with 272 clinical samples assayed in parallel with and without the internal control.

CONCLUSION

These results are sufficient to justify the incorporation of the internal control into the routine LightCycler HSV DNA assay in our laboratory.

Herpes simplex virus type 1 and respiratory disease in critically-ill patients: real pathogen or innocent bystander?

Herpes simplex virus type 1 (HSV-1) has been associated with pulmonary disease, mostly in severely immunocompromised patients. After reactivation and shedding in the oropharynx, the virus may reach the lower respiratory tract by aspiration or by contiguous spread. HSV-1 can be detected in clinical specimens by virus culture or quantitatively by nucleic acid amplification techniques. With these techniques, HSV-1 is often detected in the respiratory secretions of critically-ill patients. However, a clear diagnosis of HSV-1 pneumonia is difficult to establish because clinical criteria, radiological features and laboratory findings all lack specificity. Lower respiratory tract HSV-1 infections have not been associated with specific risk-factors. There is also an absence of consistent data concerning the effect of antiviral treatment on the outcome of critically-ill patients. Further studies are needed to better define the pathogenic role of HSV-1 in the lower respiratory tract of these patients, to improve the diagnosis, and, especially, to assess the need for antiviral treatment in the individual patient.