Evaluation of a new general primer pair for rapid detection and differentiation of HSV-1, HSV-2, and VZV by polymerase chain reaction

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.

Advantages and pitfalls of the polymerase chain reaction in the diagnosis of esophageal ulcers in AIDS patients

HIV-1-infected patients frequently have opportunistic esophageal infections which, when associated with severe immunodeficiency, can be attributed to unusual pathogens. The clinical presentation of several esophageal diseases is similar and the best method for a specific diagnosis of these patients has not been well defined. To evaluate the role of the polymerase chain reaction (PCR) in the etiologic definition of esophageal ulcers in HIV-1-infected patients, 96 esophageal biopsies from 79 HIV-1-infected patients were processed by PCR using specific primers for cytomegalovirus (CMV), herpes virus (HSV), human papilloma virus (HPV), HIV-1, Mycobacterium tuberculosis, Mycobacterium avium, Mycobacterium intracellulare, Treponema pallidum, and Haemophilus ducreyi. The PCR results were compared to the histopathologic results. Seventy-nine patients were studied (mean age: 34 years; 62% men; median CD4 + T cell = 103.59 cells/microl (range 1-795.2 cells/microl). The most common endoscopic findings were as follows: esophageal candidiasis (37.1%), esophageal ulcers (24.7%), esophagitis (11.2%), and lugol-negative areas (10.1%). The histopathologic findings in the esophageal ulcers (22 biopsies) were non-specific inflammation (31.8%), HSV (36.4%), Candida (13.6%), CMV (13.6%), or HPV disease (4.5%). In the esophageal ulcer biopsies, the PCR results were negative in 27.6% of cases, and positive for HIV (65.5%), CMV (31%), HPV (20.7%), HSV (10.3%), and H. ducreyi (6.9%). The histopathologic examination did not identify a pathogen or identified only Candida in 15 biopsies of esophageal ulcers. PCR was positive in ten (66.7%) and negative in five (33.3%) of these biopsies (idiopathic ulcers). PCR detected: HIV (53.3%), CMV (20%), HPV (13.3%), and H. ducreyi (6,7%). PCR detected more etiologic agents in esophageal ulcers than histopathology and was able to detect unusual pathogens. On the other hand, sometimes more than one pathogen was detected in the esophageal ulcers, making it difficult to reach an accurate diagnosis. This finding indicates the need for more studies to evaluate the benefit of this method in the routine evaluation of esophageal ulcer biopsies in HIV-1-infected patients.

Molecular analysis of cerebrospinal fluid in viral diseases of the central nervous system

The use of nucleic acid (NA) amplification techniques has transformed the diagnosis of viral infections of the central nervous system (CNS). Because of their enhanced sensitivity, these methods enable detection of even low amounts of viral genomes in cerebrospinal fluid. Following more than 10 years of experience, the polymerase chain reaction or other NA-based amplification techniques are nowadays performed in most diagnostic laboratories and have become the test of choice for the diagnosis of several viral CNS infections, such as herpes encephalitis, enterovirus meningitis and other viral infections occurring in human immunodeficiency virus-infected persons. Furthermore, they have been useful to establish a viral etiology in neurological syndromes of dubious origin and to recognise unusual or poorly characterised CNS diseases. Quantitative methods have provided a valuable additional tool for clinical management of these diseases, whereas post-amplification techniques have enabled precise genome characterisation. Current efforts are aiming at further improvement of the diagnostic efficiency of molecular techniques, their speed and standardisation, and to reduce the costs. The most relevant NA amplification strategies and clinical applications of to date will be the object of this review.

A duplex PCR assay for detection and genotyping of Herpes simplex virus in cerebrospinal fluid

A duplex polymerase chain reaction (PCR) assay for the detection and genotyping of Herpes simplex virus (HSV) 1 and 2 from cerebrospinal fluid (CFS) of infants was developed. The glycoprotein D (gD) gene of HSV was selected as a target for amplification. The assay is highly specific, sensitive and reproducible. Herpes simplex virus detection is performed by agarose gel electrophoresis and Southern blot using a chemiluminescent probe. The probe hybridizes to sequences common to both HSV-1 and 2. A DNA fragment of HSV gD gene was cloned and used as positive control and to determine the specificity and sensitivity of the assay. The PCR assay is user-friendly and unambiguously differentiates in one-step both herpes virus strains. The assay is useful to screen CFS specimens from infants exposed to HSV during birth and at risk of developing encephalitis.