Rapid detection of enterovirus RNA in cerebrospinal fluid specimens with a novel single-tube real-time reverse transcription-PCR assay

A single-tube real-time reverse transcription-PCR (RT-PCR) assay for enterovirus detection in cerebrospinal fluid (CSF) was developed based on a fluorogenic probe and primers directed to highly conserved sequences in the 5' untranslated region of the enterovirus genome. Quantitative detection of enterovirus genome was demonstrated in a linear range spanning at least 5 logs. Endpoint titration experiments revealed that the in-tube detection limit of the assay was 11.8 enterovirus genome equivalents (95% detection rate) corresponding in our current extraction protocol to 592 enterovirus genome equivalents per ml of CSF. Twenty CSF specimens not suspected of viral meningitis were all found to be negative, and no cross-reactivity with herpes simplex virus type 1 and type 2, varicella-zoster virus, rhinovirus type 53, and influenza viruses A and B was observed. Nineteen CSF specimens from 70 patients suspected of viral meningitis were determined to be positive by PCR (27.1%), whereas only 17 were found to be positive by viral culture (24.3%). The sensitivity of the assay was 100% and the specificity was 96.2% compared to viral culture. Data from the real-time RT-PCR assay were available within 4 h. Our data suggest that the novel real-time RT-PCR assay may offer a reliable but significantly faster alternative to viral culture. Owing to the elimination of postamplification detection steps, its conduct required considerably less hands-on time and was associated with a substantially reduced carryover risk compared to previously described PCR-based enterovirus detection assays.

[Clinical characteristics of the endogenous intoxication syndrome in Russian tick-born encephalitis]

The paper characterizes the clinical and laboratory indices of the endogenous intoxication syndrome (EIS) in 173 patients with acute Russian tick-borne encephalitis. In its feverish form, EIS is characterized by the general intoxication syndrome and a slight increase in the luciferase index (LI). In its meningeal form, EIS is accompanied by overall cerebral symptoms, cardiovascular, respiratory and hepatic detoxifying dysfunctions, which are manifested by increases in both the intoxication leukocyte index of (ILI) and LI. In its focal form, EIS is characterized by the signs of multiorgan failure with the most pronounced alterations in the laboratory indices of endotoxemia (LID and LI).

Findings in a patient with herpes simplex viral meningitis associated with acute retinal necrosis syndrome

We report the case of a 41-year-old man with clinical findings of viral meningitis associated with acute retinal necrosis syndrome in his right eye. MR images showed right optic nerve enlargement and high-intensity signal abnormalities in the region of the left lateral geniculate body and the left occipital lobe.

[Utility of Boyer's score modified for the differential diagnosis of bacterial and viral meningitis]

BACKGROUND

Many studies have been performed to establish criteria for the differential diagnosis between bacterial and viral meningitis. In 1980, Thome and Boyer proposed a score that has been widely used.

OBJECTIVES

The aim of this study was to assess the utility of this score when applied to our patients with meningitis and to evaluate the diagnostic yield after adding other laboratory tests.

METHODS

We retrospectively studied the children diagnosed with meningitis in the Hospital Niño Jesús between January 1993 and February 2000. In all patients, Boyer's score and the following laboratory variables were applied: reactive C protein levels, percentage of neutrophils in the cerebrospinal fluid depending on age, and the ratio of immature cells/total neutrophils in the blood. We calculated the sensitivity and specificity of Boyer's score and the laboratory variables.

RESULTS

Of the 476 children with meningitis, 402 had viral meningitis and 74 had bacterial meningitis. All the children with bacterial meningitis except seven had a score higher than 3 (a doubtful indication for antibiotic treatment). The sensitivity and specificity of Boyer's score was 90 % and 99 % respectively. When laboratory variables were added, sensitivity was 100 % and specificity was 98 %.

CONCLUSIONS

Boyer's score is a useful tool for the differential diagnosis of meningitis, but its diagnostic yield is considerably increased when the results of laboratory tests are added.

Detection of Coxsackievirus B 4 antibodies in cases of suspected encephalopathy by microneutralization test

A retrospective study of serum and cerebrospinal fluid (CSF) samples collected from suspected viral encephalitis and encephalopathy cases was carried-out and it included 100 CSF and 89 serum samples from Goa, collected during 1990-1994. These samples which were negative for antibodies to Japanese encephalitis (JE), West Nile (WN), Dengue-2 (DN-2) and herpes viruses, were tested for Coxsackievirus B 4 specific antibodies by 'in vitro' microneutralization technique along with 80 negative control serum samples. Out of 189 specimens (100 CSF and 89 serum), 23 CSF and 41 serum samples were positive for Coxsackievirus B 4 neutralizing antibodies. Antibody profile seemed to be IgG as revealed by mercaptoethanol treatment. The presence of neutralizing antibodies to coxsackievirus B 4 with titres as high as 1:512 in 8 CSF and 19 serum samples seemed to be suggestive of viral meningitis due to Cox B-4 viruses.

[Inner ear and subarachnoid spaces: relations and diseases]

The purpose of this article is to describe, with 5 clinical cases, the physiological communications between the inner ear and the subarachnoid spaces (SAS) and present the imaging features with regard to. Therefore we briefly illustrate abnormal communications between SAS and perilymphatic fluids in certain cochlear and internal acoustic meatus (IAM) malformations and their consequences. Imaging features may depict diffusion pathway of bacterial meningitis to membranous labyrinth via the cochlear aqueduct or via the IAM. Rarely, in some patients referred for cochleovestibular symptoms, imaging features may display skull base tumors involving the area of cochlear or vestibular aqueduct aperture. Therefore, in patients referred for cochleovestibular symptoms, MR and CT study should carefully scrutinise not only the IAM but also the aperture of the cochlear and the vestibular aqueducts and the cerebellopontine meninges.

Signs of meningeal irritation at the emergency department: how often bacterial meningitis?

OBJECTIVE

Although signs of meningeal irritation are highly indicative of meningitis, they are not pathognomonic. In this study, we described the final diagnoses in children with signs of meningeal irritation, and we assessed the frequency of bacterial meningitis related to specific signs of meningeal irritation.

METHODS

Information was collected from records of 326 patients (aged 1 month to 15 years) who visited the emergency department of the Sophia Children's Hospital between 1988 and 1998 with signs of meningeal irritation, assessed by either the general practitioner or the pediatrician.

RESULTS

Bacterial meningitis was diagnosed in 99 patients (30%), viral or aseptic meningitis in 43 (13%). Other diagnoses were pneumonia (8%), other serious bacterial infections (2%), and upper respiratory tract infections or other self-limiting diseases (46 %). Presence of one of the signs of meningeal irritation assessed by the pediatrician was related to bacterial meningitis in 39%. Specific tests eliciting meningeal irritation, such as Brudzinski's and Kernig's signs, were not related to a higher frequency of bacterial meningitis than neck stiffness and the tripod phenomenon. In children < or =1 year, bacterial meningitis is more frequently related to presence of irritability and a bulging fontanel.

CONCLUSION

Bacterial meningitis is present in 30% of children with signs of meningeal irritation. Presence of meningeal irritation as assessed by the pediatrician is related to bacterial meningitis in 39%. A better prediction of bacterial meningitis was not achieved by using more specific tests for signs of meningeal irritation.

[Rational and efficient enterovirus diagnosis]

BACKGROUND AND OBJECTIVE

Demonstration of the causative pathogen by isolating the virus in cell culture is taken as the standard in the diagnosis of diseases caused by enterovirus. When diagnosing the virus in cerebrospinal fluid (CSF), isolation of the virus has been largely replaced by the rapid demonstration of the virus using the reverse transcriptase polymerase chain reaction (RT-PCR), because of its greater sensitivity. The serological diagnosis is mostly made with the complement binding reaction (CBR). A new enzyme immunoassay for demonstrating anti-enterovirus IGM antibodies (IgM-EIA) allows a more rapid diagnosis from a single serum sample. It was the aim of this study to compare the diagnostic value of these various tests.

METHODS

Several methods for demonstrating virus from faeces, swabs and CSF (virus isolation in cell culture and RT-PCR) and of antibodies in serum (IgM-EIA and CBR) were compared. The clinical material was obtained largely from children under the age of 10 years, many of whom had serous meningitis, flu-like symptoms or enteritis. In one cohort (C1), only stool or throat swabs were available for each of 154 patients. In the other cohort (C2) of 164 patients, CSF and at least one serum sample were available in addition to occasional stool samples.

RESULTS

From C1 enteroviruses were isolated from 32 patients. rotavirus twice from stool or throat swab and rotavirus once from stool or throat swab, and herpes simplex once from throat swab. RT-PCR was positive 55 times for enterovirus, five times false-negative when the virus had been isolated. In C2 enterovirus nucleic acid was demonstrated in 43 patients from CSF. Parallel serological tests gave positive IgM values for 15 patients, while CBR titres were raised in nine.

CONCLUSIONS

Complementary tests of CSF, stool, swabs and serum samples by all possible combinations of viral isolation, RT-PCR and IgM-EIA improve the diagnosis of enterovirus-associated diseases. RT-PCR is the method of choice. The serological diagnosis should be confirmed by the demonstration of virus in stool or swab.

Viral meningitis

Enteroviruses account for 85 to 95% of all cases of aseptic meningitis, but the arboviruses and herpes simplex virus are also important etiologic agents. Mumps, lymphocytic choriomeningitis virus, herpes zoster, human herpesvirus type 6, and influenza viruses are rare causes of meningitis. The virology, pathogenesis, epidemiology, clinical manifestations, diagnostic studies, and established and potential antiviral therapies for viral meningitis are discussed. A differential diagnosis of the aseptic meningitis syndrome is provided.

[Levels of interleukin-6 in cerebrospinal fluid of patients with meningitis]

Interleukin-6 (IL-6) is a multifunctional cytokine that regulates the immune response, differentiation of B cells, activation of T lymphocytes and acute phase reactions.

AIM OF THE STUDY

Quantitation of interleukin-6 in cerebrospinal fluid from patients with purulent bacterial meningitis (PBM) and viral meningitis (VM) on the first day of hospitalization.

PATIENTS AND METHODS

IL-6 activity was measured in cerebrospinal fluid (CSF) of 15 children with VM (predominantly 13/15 caused by mumps virus) in age ranging from 2.5 to 15 years and 13 patients with PBM (age ranging from 18 to 52 years). The control group consisted of 10 patients with meningeal syndrome and normal laboratory estimation of CSF (white cells count, concentration of glucose and protein). The IL-6 assays were performed using immunoenzymatic method, ELISA (Amersham) technique.

RESULTS

Increased levels of IL-6 were detected in the CSF of patients with bacterial meningitis and with viral meningitis. CSF IL-6 levels were 6 times greater in patients with purulent bacterial versus viral meningitis. The highest level of IL-6 was observed in a 18 years old patient with pneumococcal meningitis who died.

CONCLUSION

We suggest that cytokine levels may be valuable in distinguishing patients with purulent bacterial meningitis from viral meningitis and may help in prognosis of patients with purulent meningitis.

Enterovirus infections: diagnosis and treatment

Enterovirus infections are common in both children and adults and range from benign short-lived febrile illnesses to life-threatening infections. Recent developments in nucleic acid amplification techniques now allow the rapid and sensitive diagnosis of enterovirus infections, which in turn can lead to improvements in patient management that shorten hospitalizations and reduce costs. New antiviral drugs have been developed that inhibit enterovirus replication, and early clinical trials of these compounds suggest that effective therapy for enterovirus infections is now possible.

First epidemic of echovirus 16 meningitis in Cuba

From April to September 2000, an epidemic of aseptic meningitis spread throughout Cuba, with 16,943 reported cases. Virologic studies identified echovirus 16 as the cause of this epidemic. This is the first reported isolate of echovirus 16 from patients with viral meningitis in Cuba.

Pre- and postcontrast FLAIR MR imaging in the diagnosis of intracranial meningeal pathology

PURPOSE

Few reports address the use of fluid-attenuated inversion-recovery (FLAIR) images of the brain in the diagnosis of extraaxial lesions. Our purpose was to assess the value of FLAIR images, including postcontrast ones, in the diagnosis of intracranial meningeal diseases.

METHODS

We reviewed precontrast (n=24) and postcontrast (n=20) FLAIR images obtained from 25 patients with infectious meningitis (n=13), carcinomatous meningitis or dissemination of primary brain tumor (n=7), dural metastasis (n=3), and others (n=2) in comparison with fast spin-echo T2-weighted and postcontrast T1-weighted images.

RESULTS

In lesion detectability, precontrast FLAIR images were significantly superior to fast spin-echo T2-weighted images but inferior to postcontrast T1-weighted images. There was no significant difference between postcontrast T1-weighted and FLAIR images.

CONCLUSION

Precontrast FLAIR images can substitute for conventional fast spin-echo T2-weighted images. Postcontrast FLAIR images have diagnostic potential equivalent to conventional postcontrast T1-weighted images.

[Details of meningitis in the elderly]

PURPOSE

Elderly patients being more at risk for infections than younger people, this study was aimed at defining the epidemiological and clinical features of meningitis in this population, with the objective of improving diagnosis and management.

METHODS

Over a period of 10 years, all cases admitted to an infectious diseases unit for acute meningitis were reviewed. Patients infected by human immunodeficiency virus (HIV), fungi meningitis, and who were younger than 15 years of age were excluded from the study. According to age, two groups were constituted (group A: < 65 years and group B: > or = 65 years) and compared.

RESULTS

One hundred fifty-two patients were included in the study: 110 (72.4%) in group A (29 with bacterial and 81 with viral meningitis) and 42 (26.7%) in group B (32 with bacterial and ten with viral meningitis); the mean age was, respectively, 32.7 +/- 12.9 years (range: 15-61 years) and 75.9 +/- 7.6 years (range: 65-94 years). Diagnosis was less frequently evoked in the elderly (n = 11; 26%) than in younger patients (n = 78; 71%) (P < 0.001). Streptococcus pneumoniae, Listeria monocytogenes, and herpes simplex virus were the three most common causal agents in group B. Confusion was the most common symptom among the elderly (88 vs. 17%; P < 0.001). The mortality rate was more important in group B than in group A (11.9 vs. 2.7%; P = 0.04).

CONCLUSIONS

Diagnosis of acute meningitis is difficult and must be evoked in the presence of any new neurologic sign. Cranial computerized tomography should not delay lumbar puncture, except in the presence of focal neurologic symptoms. Antimicrobial therapy takes into account the bacterial epidemiology.

A single tube PCR assay for simultaneous amplification of HSV-1/-2, VZV, CMV, HHV-6A/-6B, and EBV DNAs in cerebrospinal fluid from patients with virus-related neurological diseases

Cerebrospinal fluid (CSF) specimens from 27 patients with encephalitis, meningitis, and other neurological diseases were studied for the presence of herpes simplex virus types 1 and 2 (HSV-1/-2), varicella-zoster virus (VZV), cytomegalovirus (CMV), human herpesviruses 6A and 6B (HHV-6A/-6B) and Epstein-Barr virus (EBV) DNA using the polymerase chain reaction (PCR) method. The DNAs were amplified using two sets of consensus primer pairs in a single tube, bringing simultaneous amplification of the herpesviruses. The PCR products were analyzed by agarose gel electrophoresis, and Southern blot hybridization with virus-type specific probes, thus allowing discrimination between the different types of herpesviruses to be made. Each virus-specific probe was highly specific for identifying the PCR product. Thirty CSF specimens from 13 patients with encephalitis and 10 specimens from 10 patients with meningitis, respectively, were examined using this method. Eight patients with encephalitis and six with meningitis were positive for different herpesviruses, including patients with coinfections (HSV-1/-2 and VZV, VZV and CMV). Among four CSF specimens from four patients with other neurological disorders, dual amplification of CMV and EBV was present. Since identification of the types of herpesviruses in this system requires a very small amount of CSF, and is completed with one PCR, it is useful for routine diagnosis of herpesvirus infections in diagnostic laboratories. The viruses responsible for central nervous system infection are easily detected with various coinfection and serial patterns of herpesviruses, by this consensus primer-based PCR method. This may give an insight into the relationship between virus-related neurological diseases (VRNDS) and herpesvirus infections.

Chronic parvovirus B-19 meningoencephalitis with additional detection of Epstein-Barr virus DNA in the cerebrospinal fluid of an immunocompetent patient

Parvovirus B19 DNA was detected by polymerase chain reaction in the brain biopsy specimen from a 67-year-old immunocompetent woman with severe chronic lymphocytic meningoencephalitis. In addition to parvovirus B19, Epstein-Barr virus DNA was identified in the CSF. Genomic material from Epstein-Barr virus was absent in the brain tissue. Clinical symptoms and CSF pleocytosis improved under long-term corticosteroid-treatment. The aetio-pathogenetic role of parvovirus B19 and the possible meaning of the additionally detected Epstein-Barr virus DNA are discussed.

Time-resolved fluorometry PCR assay for rapid detection of herpes simplex virus in cerebrospinal fluid

We have introduced a time-resolved fluorometry (TRF)-based microwell hybridization assay for PCR products in detection of herpes simplex virus (HSV) in cerebrospinal fluid (CSF) specimens. TRF is a sensitive nonradioactive detection technique which involves the use of lanthanide chelates as fluorescent labels. We used PCR primers from the glycoprotein D genes of HSV type 1 (HSV-1) and HSV-2. The biotinylated PCR products were collected on streptavidin-coated microtitration wells and hybridized with short oligonucleotide probes, europium labeled for HSV-1 and samarium labeled for HSV-2. The TRF results were obtained as counts per second and as signal-to-noise (S/N) ratios. The sensitivity of the assay was 0.1 infectious units (PFU) of HSV in CSF specimens, and the S/N values increased with the virus amount, up to 68.5 for 10(3) PFU of HSV-1 and to 58.5 for 10(3) PFU of HSV-2, allowing semiquantitation of HSV in CSF. The primers and probes recognized all the studied 48 HSV wild-type samples, with S/N ratios of 12.4 to 190 (HSV-1) and 5.1 to 248 (HSV-2). We tested CSF specimens, 100 for each HSV type, which were HSV PCR negative by Southern blot and 22 CSF specimens which were HSV-1 or -2 PCR blot positive. In the TRF test, the mean S/N ratio for the HSV-1-negative CSF was 1.37 (standard deviation [SD] = 0.513) and for the HSV-2-negative CSF it was 1.03 (SD = 0.098). The HSV-1 blot-positive CSF yielded S/N ratios of 3.6 to 85.9, and the HSV-2 blot-positive CSF yielded ratios from 1.9 to 13. Using the mean S/N ratio for negative CSF specimens + 3 SD as the cutoff yielded all the previously HSV-positive specimens as TRF positive. The TRF PCR assay for HSV in CSF specimens is a rapid and sensitive method, improves interpretation of PCR results, and is well suited for automation.

A one-step RT-PCR assay using an enzyme-linked detection system for the diagnosis of enterovirus meningitis

BACKGROUND

Enteroviruses are the most common cause of meningitis in the United States, with an estimated 50000-75000 cases each year. Enteroviral meningitis (EVM) is frequently a diagnosis of exclusion, as viral cultures lack sensitivity and require prolonged incubation periods.

OBJECTIVE

To develop a sensitive and rapid test for the diagnosis of EVM.

STUDY DESIGN

A rapid, one-step, reverse transcriptase-polymerase chain reaction (RT-PCR) was used in a prospective analysis of 160 patients who had cerebrospinal fluid (CSF) tested for enterovirus.

RESULTS

Of the 160 patients, 14 were excluded due to missing CSF viral culture data. A total of 14 were CSF culture positive (10 with pleocytosis) and 19 were PCR positive (15 with pleocytosis). The ability to detect enterovirus by either culture or PCR correlated significantly with the white blood cell count in the CSF (P=0.001). Based on a clinical definition of enterovirus culture positive and pleocylosis: ten had definite EVM and 12 had probable EVM (pleocytosis without any other cause). Four had possible EVM (CSF culture positive without pleocytosis) and 18 had pleocytosis due to other causes. PCR was positive in all ten patients with definite EVM. Five out of 12 patients with probable EVM and three out of four patients with possible EVM. No patients with pleocytosis due to other causes were PCR positive and one patient that was defined as EVM negative (culture negative and no pleocytosis) was PCR positive. Overall, PCR was positive in 18 out of the 26 patients with a likelihood of EVM, while CSF culture was positive in only 14 cases. Our results demonstrated that RT-PCR enhances the sensitivity of enterovirus detection in CSF (69 vs. 54% for culture).

CONCLUSION

The diagnosis of EVM is difficult to make clinically: the enhanced sensitivity and rapid turn around time of PCR will be of great clinical benefit.

Cost analysis of enteroviral polymerase chain reaction in infants with fever and cerebrospinal fluid pleocytosis

BACKGROUND

Infants with fever and cerebrospinal fluid (CSF) pleocytosis are routinely admitted to the hospital for parenteral antibiotic therapy for potential bacterial meningitis pending results of CSF culture. Published estimates suggest that 90% of all episodes of meningitis are caused by enterovirus. Enteroviral polymerase chain reaction (ePCR) has a sensitivity of 92% to 100% and a specificity of 97% to 100% in CSF.

OBJECTIVE

To compare a management strategy using ePCR with current practice to determine potential savings by allowing earlier discharge.

METHODS

Decision analysis comparing 2 strategies for the care of a retrospective cohort of infants with fever and CSF pleocytosis: standard practice vs ePCR testing of all CSF samples. Model assumptions include the following: (1) standard practice patients continue parenteral antibiotic therapy until CSF cultures are negative at 48 hours, (2) patients with positive ePCR results would be discharged after 24 hours, (3) patients with positive ePCR results have a negative CSF culture, and (4) costs are calculated from actual patient charges with a cost-to-charge ratio of 0.65.

SUBJECTS

All infants aged 28 days to 12 months admitted to an urban teaching hospital with fever, CSF pleocytosis, and a negative CSF Gram stain from January 1996 through December 1997.

OUTCOME MEASURE

Total cost of hospitalization.

RESULTS

A total of 126 infants were identified. One hundred twelve (89%) were discharged with a diagnosis of aseptic meningitis; 72% of these cases occurred during the peak enterovirus season (June to October). Three of 3 patients with positive CSF cultures had bacterial growth within 24 hours of admission. Mean length of stay for patients with aseptic meningitis was 2.3 days (SD, +/-1.4 days). Total cost of hospital care for all 126 infants was $381,145. In our patient population, total patient costs would be reduced by the ePCR strategy if enterovirus accounts for more than 5. 9% of all meningitis cases. Varying the sensitivity of the ePCR assay from 100% to 90% changes the "break-even" prevalence from 5.8% to 6.5%. Total cost savings of 10%, 20%, and 30% would occur at an enteroviral meningitis prevalence of 36.3%, 66.7%, and 97.1%, respectively.

CONCLUSIONS

Enteroviral PCR analysis of CSF for infants admitted to the hospital with meningitis can result in cost savings when the prevalence of enteroviral meningitis exceeds 5.9%. Limiting use of ePCR to the enterovirus season would increase cost savings. A prospective study is needed to validate these results. Arch Pediatr Adolesc Med. 2000;154:817-821

Intra-CSF administered recombinant adenovirus causes an immune response-mediated toxicity

High doses of adenotk were injected into the cerebrospinal fluid of rats and nonhuman primates (Macaca mulatta). Vector administration was followed by ganciclovir administration for 14 days. Despite the absence of clinical symptoms, analysis of the cerebrospinal fluid (CSF) and histopathological examination of the central nervous system (CNS) of the monkeys (3 weeks after vector injection) were consistent with a viral meningitis. Immunohistochemical analysis of the inflammatory infiltrates in the monkeys revealed the presence of T and B lymphocytes, indicating a combined cellular and humoral immune response to the vector. This latter was supported by the finding of intrathecal anti-adenovirus antibody synthesis. Rats receiving high intrathecal adenotk doses showed a transient and dose-dependent clinical toxicity consisting of lethargy, hyperemic eyes and weight loss. Histopathological examination of the meninges showed a shift from polymorphonuclear infiltrates during the first post-injection days to clusters of mononuclear cells after 7 days. Acute toxicity is probably related to the early, innate immune response to the vector. In a separate experiment, high levels of IL-8 and IL-6, were measured during the first 2-3 post-injection days in the CSF of two monkeys which received intrathecal adenoLacZ. Therefore, these cytokines seem to play an important role in initiating the nonspecific immune response. In one monkey which received adenotk, recombinant adenovirus was cultured from serum samples obtained at the 7th post-injection day. At this time-point, no vector could be isolated from CSF samples. Based on these preclinical data, we recommend careful dose finding for clinical studies that aim to treat patients with leptomeningeal metastases.