Enteroviral polymerase chain reaction in the investigation of aseptic meningitis

Assessment of a multiplex RT-PCR for Simultaneous, Rapid Screening of Common Viral Infections of Central Nervous System: A Prospective Study for Enteroviruses and Herpesviruses

Introduction

Acute meningitis is a common neurological disorder that affects both children and adults and has a high mortality rate. This study aimed to create a multiplex reverse transcriptase PCR system for screening clinical samples for the presence of the two viruses currently considered to be the most common causes of acute meningitis in Asia.

Materials and Methods

A single-tube RT multiplex PCR assay was developed and tested for sensitivity and specificity using primers that have been commonly used to screen for herpes simplex viruses 1 and 2 (HSV-1/2) and enterovirus (EV) in clinical samples. The procedure was then used to screen 303 clinical samples for the target viruses, which included 101 feces samples, 101 throat swabs, and 101 cerebrospinal fluid (CSF) samples obtained from 101 hospitalized Iranian children with suspected viral meningitis/meningoencephalitis, and the findings were compared to those of an RT monoplex PCR method.

Results

The RT-PCR approach demonstrated high precision, with no non-target virus amplification. The results of using this assay to screen clinical samples revealed that RT monoplex PCR had the same sensitivity as RT multiplex PCR for the three different types of specimens.

Conclusions

This newly developed multiplex RT-PCR method is a simple, fast diagnostic tool that can be used to screen clinical samples for viruses that cause acute meningitis/meningoencephalitis in children.

Enterovirus and parechovirus infection in children: a brief overview

Enterovirus and parechovirus are a frequent cause of infection in children. This review is an overview of what is known from enterovirus and parechovirus infection in children and contains information about the epidemiology, pathogenesis, clinical presentation, diagnosis, treatment, and prognosis of enterovirus and parechovirus infection in children.

CONCLUSIONS

EV and HPeV infections are a frequent cause of infection in childhood. The clinical presentation is diverse. RT-qPCR is the best way to detect an EV or HPeV. Cerebrospinal fluid, blood and feces have the highest sensitivity for detecting an EV or HPeV. There is no treatment for EV and HPeV infections. Two vaccines against EV 71 are just licensed in China and will be available on the private market. Little is known about the prognosis of EV and HPeV infections.

WHAT IS KNOWN

•EV and HPeV are a frequent cause of infection in children. What is new: •This review gives a brief overview over EV and HPeV infection in children.

Epidemic Trends of Enterovirus Infections From Pediatric Patients in Cheonan, Korea

BACKGROUND

This study was performed to investigate the epidemiology of enterovirus (EV) infections in children at a single hospital during recent 5 years. This study was preformed from December 2008 to November 2013.

METHODS

We subjected 1,067 cerebrospinal fluid (CSF) specimens from 1,053 patients and 678 stool specimens from 665 patients using real-time reverse-transcription polymerase chain reaction tests that could detect EV. The data were analyzed according to seasonality and patient age and sex.

RESULTS

During this period, 176 of the total 1,053 patients (16.81%) were positive for EV in CSF. The highest rate of EV-positive samples occurred in children less than 1 year of age (114/176, 64.77%), and the most prevalent month was June. The results for CSF and stool specimens were concordant in 545 (80.38%) of 678 cases.

CONCLUSION

We described the epidemiological analytic data of the EV in the population of Cheonan, South Korea. The combination of the CSF and stool specimen enhances the diagnostic yield. There is a need for continuous study of EV infections and its clinical manifestations.

Prospective comparison of the detection rates of human enterovirus and parechovirus RT-qPCR and viral culture in different pediatric specimens

BACKGROUND

Reverse-transcriptase quantitative real-time polymerase chain reaction (RT-qPCR) has become the gold standard for the diagnosis of human enterovirus (EV) and parechovirus (HPeV) infections. The detection rate of RT-qPCR in different pediatric body specimens has not been compared prospectively in a multicentre study.

OBJECTIVES

This study compared the diagnostic detection rates of EV and HPeV RT-qPCR and viral culture in different specimens (feces, nasopharynx, blood, urine and cerebrospinal fluid (CSF)) of pediatric patients.

STUDY DESIGN

This prospective, multicenter study performed an EV and HPeV RT-qPCR on nasopharynx, blood, urine, feces and CSF specimens and a viral culture on nasopharynx, feces and CSF specimens in symptomatic children<16 years.

RESULTS

Of 285 included children EV was detected in 140 (49%) and HPeV in 44 (15%) children. Both EV and HPeV RT-qPCR had a higher sensitivity and negative predictive value than EV and HPeV viral culture, respectively. EV and HPeV RT-qPCR in feces specimen had the highest sensitivity (99.2% and 95.1%) of all specimens. Pooling results of specimens increased the detection rate for both viruses.

CONCLUSION

Of all specimens, RT-qPCR in feces had the highest detection rate for both EV and HPeV in symptomatic pediatric patients. An EV was detected in all EV positive patients if a RT-qPCR was performed on both feces and CSF specimens or in both feces and urine specimens. HPeV was detected in all HPeV positive patients if a RT-qPCR was performed on both feces and CSF specimens, feces and nasopharynx specimens or CSF and nasopharynx specimens.

Du diagnostic moléculaire initial prospectif des méningites à entérovirus⋯ à la lutte contre l'antibiorésistance

Meningitis initially presents with intense manifestations that are not generally specific to a given etiology. The first major question for the physician is to decide whether to initiate a probabilistic treatment. Enteroviruses are a major cause of aseptic meningitis, which is benign in immunocompetent patients. Molecular diagnosis is now becoming the gold standard and its prospective use at the time of patient admission, on the sole basis of clinical suspicion of meningitis, has yielded more reliable data. Cytological and biochemical data from CSF analyses are of low predictive value to influence the initial decision to treat with antibiotics. In addition, cases of meningitis during winter are not uncommon. Adults are concerned in about 25% of cases. Thus, if molecular diagnostic tools are not rapidly available, patient management may be inconsistent, leading to unnecessary scans, laboratory investigations and treatment (including overconsumption of antibiotics). Current progress in the automation and practicability of viral genomic detection yields the result within a few hours after admission. Rapid molecular viral diagnosis of a benign disease that does not require treatment but which is initially worrying is of unquestionable advantage. It is of benefit to both the patient and the community because of its input on health economics, the needless consumption of drugs and, as a result, resistance to antibiotics. The diagnosis of meningitis can no longer remain a retrospective diagnosis after elimination of all the possible causes, since not prescribing unnecessary laboratory tests and not treating are true therapeutic decisions.

Diagnosis of Enteroviral Meningitis by Use of Polymerase Chain Reaction of Cerebrospinal Fluid, Stool, and Serum Specimens

BACKGROUND

Because enteroviruses can be detected in various clinical samples during enteroviral meningitis, we analyzed the combined diagnostic utility of polymerase chain reaction (PCR) of cerebrospinal fluid (CSF), feces, and serum for detection of enterovirus in specimens obtained from adults with aseptic meningitis or encephalitis.

METHODS

PCR results were analyzed for 34 adults for whom enteroviral meningitis was diagnosed on the basis of virus isolation and antibody detection in our hospital during 1999-2003. PCR results were also analyzed for 77 adults with meningitis or encephalitis of another defined cause for whom this assay was used for diagnostic evaluation during that period.

RESULTS

Twenty-six (76%) of 34 CSF samples and 24 (96%) of 25 fecal samples collected from patients with enteroviral meningitis had positive PCR results. The diagnostic yield of the test was lower for CSF specimens obtained >2 days after clinical onset, compared with CSF collected < or =2 days after onset. Instead, PCR of feces was highly useful also later, because 12 of the 13 fecal specimens obtained 5-16 days after clinical onset had positive test results. None of 75 CSF samples and 2 of 48 fecal samples obtained from patients with nonenteroviral infection had positive PCR results. All serum samples were PCR negative.

CONCLUSIONS

PCR of fecal specimens obtained throughout the course of enteroviral meningitis had the highest clinical sensitivity for detecting enterovirus. It is recommended that, in addition to performance of CSF PCR, fecal samples collected from patients with suspected enteroviral meningitis should be tested by PCR, especially when the duration of symptoms is >2 days.

An echovirus type 33 winter outbreak in New Zealand

Echovirus type 33 (E33) is a relatively uncommon enterovirus. An E33 outbreak during the winter of 2000 in New Zealand led to 75 virologically-confirmed cases of E33 infection (2.6 cases per 100,000 individuals). Sixty-six (88%) of the 75 patients were aged <30 years, with the highest rates of infection recorded in Maori and Pacific ethnic groups. Overall, 47 (84%) of 56 patients whose cases were analyzed had either aseptic meningitis or encephalitis. Central nervous system involvement was more common after infancy (43 of 45 non-infant patients vs. 4 of 11 infants [relative risk, 2.6; 95% CI, 1.5-4.3]). Two infants died, including a neonate with fulminant hepatitis. Independent of symptom duration, neutrophil-predominant pleocytosis was detected in 17 (41%) of 41 cerebrospinal fluid specimens. Virus isolates could not be definitively typed by antibody neutralization testing but were identified as E33 by partial sequencing of the VP-1 capsid gene. The isolates were closely related to strains from Australia and Oman. Molecular typing, together with a serotype-specific E33 PCR, improved the speed and effectiveness of the outbreak investigation.

A retrospective clinical, laboratory and outcome analysis in 43 cases of acute aseptic meningitis

Forty-three consecutive cases of acute aseptic meningitis (AAM) presenting within a 24-months period were retrospectively analysed with respect to clinical symptomatology, cerebrospinal fluid (CSF) findings, clinical course, treatment and outcome. Nineteen of the 43 AAM cases (44%) were caused by enterovirus, one by HIV (2%), two by Varicella zoster virus (5%), three due to herpes simplex virus I (7%), two due to herpes simplex virus II (5%), one due to Central European encephalitis virus (2%), and in 15 patients (35%) the aetiology of AAM remained unknown. Headache (100%) and fever (93%) were the presenting symptoms in the majority of cases. Signs of preceding infection were predominantly gastrointestinal in the enterovirus subgroup, but were inconsistently observed in the other subgroups. CSF findings at the first lumbar tap on admission generally revealed lymphomonocytic pleocytosis of less than 500 cells per micro l, mild to moderately elevated protein and normal lactate and glucose levels. Initial therapy consisted of an empirical antiviral and antibiotic regimen until a serological diagnosis was available. Acyclovir, effective only in herpes family viruses, was initially administered to all AAM cases. Effective therapy for other viral pathogens are not broadly available and treating AAM of unknown aetiology imposes a particular problem. The average hospitalization time ranged from 16 to 31 days. Patients were either discharged home (72%) or transferred to a rehabilitation centre (28%). The outcome was good (40%) to fair (51%) in the majority of cases.

[Enteroviral meningitis in adults, underestimated illness: description of 30 observations from 1999 to 2000, and evolution of clinical practices during 2001]

Enteroviral meningitis is well documented in children but underestimated in adults. The analysis of 30 cases of adult meningitis prospectively diagnosed by enterovirus genome detection (RT-PCR) in cerebrospinal fluid (CSF) between 1999 and 2000 in routine practice showed diagnosis to be problematic. Characteristic symptoms were inconstant (the association of fever/headache/stiff neck absent in 41%) and sometimes misleading (the presence of peribuccal lesions). CSF data showed a predominance of lymphocytes in only 44% of patients. The most reliable criterion was normal constant CSF glucose levels. Thirty three per cent of patients were admitted during cold months. Management of patients varied markedly between departments, and included computed tomography (33%), and the prescription of aciclovir (20%) or antibiotics (53%). A report of positive enterovirus RT-PCR had only low impact on management because it took 6 days to obtain the results (versus 3 days in children during the same period). These findings were communicated to all hospital physicians concerned and as a result, the number of RT-PCR in adults increased significantly during 2001. Again, enteroviral meningitis was diagnosed in adults despite a much lower incidence of the illness in 2001 compared to 2000. Thus this pathology should not be underestimated in adults. Considerable medical expenditure might be avoided (cumulative numbers of 172 days in hospital and 82 days of antibiotics in this study), if rapid and accurate diagnostic techniques were available.

Development and evaluation of a 'real-time' RT-PCR for the detection of enterovirus and parechovirus RNA in CSF and throat swab samples

A two-step reverse transcriptase TaqMantrade mark duplex PCR (RT-PCR) assay was developed using the ABI 7700 Sequence Detection System for the detection of enterovirus (EV) and parechovirus type 1 and 2 (PEV) RNA from samples of cerebrospinal fluid (CSF) and throat swabs. Using sequence-specific fluorescent dye labeled probes and continuous 'real-time' monitoring, PCR amplified product accumulation was measured. Based on limiting dilutions, the TaqMantrade mark enterovirus and parechovirus RT-PCR showed an increase of two orders of magnitude compared to cell culture with sensitivity of 100% (7/7) when assessed using enterovirus cell culture positive samples (CSF, TS). The assays were specific for enterovirus and parechovirus and did not amplify a wide selection of virus and bacterial isolates. RNA was amplified from 22 enterovirus serotypes: coxsackie A7, A9, A21; coxsackie B2, B3, B4, B5; echovirus 2, 4, 6, 7, 9, 11, 13, 17, 18, 19, 30, 31; poliovirus types 1, 2, and 3, and parechovirus types 1 and 2. The assay was used to assess the incidence of enterovirus and parechovirus RNA in cell culture negative CSF and throat swab samples (n = 200). An additional 33 (15.9%) enterovirus and 2 (1%) parechovirus were identified as positive by RT-PCR. Also, of 100 CSF samples from suspected cases of meningococcal meningitis submitted for meningococcal PCR testing, 59 (59%) were enterovirus and 2 (2%) parechovirus 1 and 2 were positive by RT-PCR. The TaqMantrade mark duplex assay offers a more rapid and sensitive alternative to conventional cell culture for the diagnosis of enterovirus and parechovirus infection. Closed tube real-time detection using the ABI Sequence Detection System obviates the need for post-PCR manipulation, which reduces hands on time and eliminates the risk of contamination from amplified PCR product.

Detection of enteroviruses in cases of neurological disorders in the State of Pará, Brazil

Eighty-one cerebrospinal fluid (CSF) samples mainly from cases of aseptic meningitis and motor deficiency syndrome were sent to the Virology Section of Evandro Chagas Institute, Belém Pará, in the period of January 1995 to January 1996 in order to isolate viruses. All samples were inoculated onto HEp-2 cell culture and newborn mice, with negative results. The probability of isolating viruses by these methods is reduced because of the low concentration of viral particles in these specimens. In order to obtain more information about the etiology of these cases, a group of 23 samples were selected to be tested by a more sensitive technique than the virus isolation - the reverse transcription polymerase chain reaction (RT-PCR). Specific primers directed to conserved regions in the enterovirus genome were used, considering that this group of viruses is frequently associated with these neurological disorder. The age of the patients ranged from 1 to 55 years and nearly all of them lived in Belém, State of Pará, North of Brazil. Of 15 samples analyzed by RT PCR nine (60%) were positive; of these, 6 (66.6%) had motor deficiency and 3 (33.3%) developed aseptic meningitis. These results show that it is important to investigate enterovirus as cause of these syndromes.

Circulation of enteroviruses and persistence of meningitis cases in the winter of 1999-2000

The seasonal incidence of enterovirus meningitis was analyzed in a prospective study of patients admitted for suspected meningitis from October 1, 1998 to April 30, 2000. In-house reverse transcription-polymerase chain reaction (RT-PCR) in cerebrospinal fluid (CSF) was used irrespective of cytological results. Fifty-two (45.2%) of the 115 patients had positive RT-PCR in CSF, including 44/86 children (51.2%) and 8/29 adults (27.6%). Six of the 52 (11.5%) had no pleocytosis. The numbers of CSF specimens with a predominance of lymphocytes or a predominance of neutrophils were closely similar. In 33 of the positive patients, an enterovirus, mainly echoviruses type 6 (48%) and 30 (24%), was recovered in one or more specimens. Sixteen cases of enteroviral meningitis were observed between November 1999 and March 2000 as against 2 cases between November 1998 and March 1999, showing that the disease persisted through the winter months of 1999-2000. During the same period, 96 enterovirus isolates were recovered from clinical specimens from other patients. The number of isolates was higher in the winter of 1999-2000 (P < 0.01) than in the winter of 1998-1999, indicating that the risk of enterovirus infection increased significantly in winter 1999-2000. Sixteen patients had aseptic meningitis, made a rapid recovery and had an enterovirus in throat swabs and stools (9/16) or in one of the two (7/16). RT-PCR was not requested. Nine patients were admitted during the cold months. The clinical management of both adult and child patients could be improved by year-round use of enterovirus generic RT-PCR.

Prospective analysis of 61 cases of enteroviral meningitis: interest of systematic genome detection in cerebrospinal fluid irrespective of cytologic examination results

BACKGROUND

Enteroviruses are the most commonly identified cause of viral meningitis. Detection of the enterovirus genome in cerebrospinal fluid (CSF) using reverse-transcription polymerase chain reaction (PCR) has proved to be useful in diagnosis and is more rapid and sensitive than viral cultures. In routine practice, cytologic examination results of CSF are obtained swiftly and PCR indication is performed as a second step.

OBJECTIVES

The aim of this study was to determine, by analysis of complete data from CSF results for 61 cases of proven enteroviral meningitis, whether cytologic CSF findings can be used to establish viral etiology and to indicate if PCR assay should be performed.

STUDY DESIGN

From a prospective study of children admitted during 1997 for suspected enterovirus meningitis in which PCR and viral cultures of CSF were systematically performed, we selected 61 patients with proven enterovirus meningitis. We compared global white cell count (WCC), relative percentage of lymphocytes/neutrophils, PCR and culture for enterovirus, patient age, and clinical data.

RESULTS

92% of patients (56/61) had positive PCR in CSF and in 48% (29/61) enterovirus was isolated in CSF. Nine patients (14.75%) had WCC<10/mm(3); eight of them had positive PCR and two had positive culture. There were comparable numbers of CSF with a predominance of lymphocytes (n=25) and CSF with a predominance of neutrophils (n=22), and of positive PCR and positive cultures of CSF in the two groups. Results were not influenced by the age of the patients.

CONCLUSION

Irrespective of other CSF parameters, it seems difficult to dispense with PCR assay for enterovirus genome detection. It should be introduced as a true rapid routine test. Early reporting of a positive PCR result could result in a considerable saving in health resources.

Reverse-transcription polymerase chain reaction detection of the enteroviruses

OBJECTIVE

This review focuses on commercial and in-house-developed reverse-transcription polymerase chain reaction (RT-PCR) assays used for the detection of enteroviral infections. In addition to providing details on the performance of RT-PCR, its specificity, and sensitivity, the clinical utility of this diagnostic method with specific reference to its impact on hospitalization and cost savings is addressed.

DATA SOURCES

MEDLINE was searched for reports relating to RT-PCR detection of the enteroviruses in adults and children. The search was restricted to studies reported in English language journals.

STUDY SELECTION

Reports documenting detailed information regarding the RT-PCR conditions, primers, sensitivity, specificity and, if relevant, clinical impact were selected for analysis.

DATA EXTRACTION

Details regarding method of extraction of the enteroviral genome, the primers used, RT-PCR conditions, and sensitivity and specificity of the assay were extracted from the literature. For reports detailing the use of RT-PCR in the clinical management of enteroviral infections in children, the reduction in duration of hospitalization and health care cost savings were recorded.

DATA SYNTHESIS

Reverse-transcription PCR can increase the yield of detection of enteroviruses from cerebrospinal fluid by a mean of approximately 20% over tissue culture. Reverse-transcription PCR of cerebrospinal fluid has been shown to exhibit sensitivity and specificity values of 86% to 100% and 92% to 100%, respectively. Reductions of 1 to 3 days of hospitalization per patient are predicted if RT-PCR is used to diagnose enteroviral meningitis in children.

CONCLUSIONS

Reverse-transcription PCR detection of enteroviral infections is an extremely rapid, sensitive, and specific diagnostic modality. Both commercial assays and assays developed in-house appear to be equivalent with regard to sensitivity and specificity. Reverse-transcription PCR diagnosis of enteroviral infections in children could reduce the length of hospitalization and result in significant health care cost savings.

Rapid shell vial culture technique for detection of enteroviruses and adenoviruses in fecal specimens: comparison with conventional virus isolation method

Detection of enteroviruses and adenoviruses mainly in fecal specimens by rapid culture with inoculation onto cell monolayers in flat-bottom tubes by centrifugation and immunofluorescence staining with genus-specific monoclonal antibodies was compared with that by the conventional virus isolation procedure. For both conventional culture and shell vial culture human lung fibroblast cells and tertiary monkey kidney cells were used. For enterovirus detection, 979 clinical specimens (916 stool specimens, 56 cerebrospinal fluid specimens, and 7 nasopharyngeal swabs) were used. Conventional culture detected 74 enterovirus isolates. A cytopathic effect compatible with the presence of an enterovirus after 3 days of incubation occurred in 25 of the 74 (34%) specimens that eventually became positive. The detection rate for enteroviruses by rapid cell culture after 2 to 3 days of incubation was 42 of 74 (57%). The genus-specific enterovirus monoclonal antibody did not react with strains of echovirus types 22 and 23 or enterovirus type 71. Rapid cell culture for the detection of adenoviruses was performed with 567 clinical specimens (536 stool specimens, 25 cerebrospinal fluid specimens, and 6 miscellaneous specimens), in which 42 adenoviruses were found by conventional culture. Nine of the 42 (21%) adenovirus isolates were detected by conventional culture within 3 days after inoculation, whereas 21 (50%) were found by rapid cell culture within 2 to 3 days. Only two of the nine specimens found to be positive for the enteric adenovirus type 41 by conventional culture as well by a type-specific enzyme-linked immunosorbent assay (ELISA) tested positive by rapid cell culture. In conclusion, the rapid shell vial assay allows the early detection and identification of enteroviruses and adenoviruses in clinical specimens but is markedly less sensitive than the conventional isolation procedure according to the eventual results of the conventional isolation procedure. Conventional cell culture remains a prerequisite for serotyping of enteroviral isolates. On the basis of the results for adenovirus type 41, the rapid detection of adenoviruses was not considered to be useful for the detection of clinically relevant adenoviruses in fecal samples.