Detection by PCR of enteroviruses in cerebrospinal fluid during a summer outbreak of aseptic meningitis in Switzerland

Distinguishing community-acquired bacterial and viral meningitis: Microbes and biomarkers

Diagnostic tools to differentiate between community-acquired bacterial and viral meningitis are essential to target the potentially lifesaving antibiotic treatment to those at greatest risk and concurrently spare patients with viral meningitis from the disadvantages of antibiotics. In addition, excluding bacterial meningitis and thus decreasing antibiotic consumption would be important to help reduce antimicrobial resistance and healthcare expenses. The available diagnostic laboratory tests for differentiating bacterial and viral meningitis can be divided microbiological pathogen-focussed methods and biomarkers of the host response. Bacterial culture-independent microbiological methods, such as highly multiplexed nucleic acid amplification tests, are rapidly making their way into the clinical practice. At the same time, more conventional host protein biomarkers, such as procalcitonin and C-reactive protein, are supplemented by newer proteomic and transcriptomic signatures. This review aims to summarise the current state and the recent advances in diagnostic methods to differentiate bacterial from viral meningitis.

Molecular Amplification and Cell Culturing Efficiency for Enteroviruses' Detection in Cerebrospinal Fluids of Algerian Patients Suffering from Meningitis

Enteroviruses (EVs) represent a major cause of viral meningitis, being responsible for nearly 1 billion infections each year worldwide. Several techniques were developed to obtain better diagnostic results of EV infections. Herein, we evaluated the efficiency of EV detection through isolation on both Rhabdomyosarcoma (RD) and Vero cell line cultures, conventional reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR. Thus, 50 cerebrospinal fluid (CSF) samples belonging to patients suspected to have viral meningitis in northern Algeria were collected, anonymously numbered from 1 to 50 and subjected to the above-mentioned techniques for EV detection. Using real-time RT-PCR, 34 CSF samples were revealed to be positive for viral origin of meningitis (68%). Thirteen of them were positive when the conventional RT-PCR was used (26%), and only three samples gave positive results when the cell culture technique was used (6%). Surprisingly, two cell culture-positive CSF samples, namely, 31 and 39, were negative using RT-PCR directly on the original samples. However, they turned to be positive when amplification was carried out on their corresponding cell culture supernatant. The cell-cultured viral isolates were then identified by sequencing their viral genome's VP1 regions. All of them were revealed to belong to the echovirus 27 strain. This investigation demonstrates that RT-PCR techniques are often more sensitive, accurate and much faster, providing reliable results within a clinically acceptable timeframe. However, viral isolation on cell cultures remains crucial to obtain enough viral load for serological tests or even to avoid the rare, but existing, false negative PCR.

The impact of cerebrospinal fluid viral polymerase chain reaction testing on the management of adults with viral meningitis: A multi-center retrospective study

The aim of this study was to evaluate the role of viral polymerase chain reaction (PCR) testing in patients with aseptic meningitis and identify opportunities for improvement in clinical management. All cerebrospinal fluid samples collected in 1 year from four teaching hospitals in Sydney, Australia, were reviewed. Patients with aseptic meningitis were selected, and clinical and diagnostic features, hospital length of stay (LOS), and treatment were analyzed. Identifying a cause by viral PCR did not reduce hospital LOS (median 3 days) or antibiotic use (median 2 days), but the turnaround time of the PCR test correlated with LOS (Rs = 0.3822, p = 0.0003). Forty-one percent of patients received intravenous acyclovir treatment, which was more frequent in patients admitted under neurologists than infectious diseases physicians (56% vs. 24%; p = 0.013). The majority of patients did not have investigations for alternative causes of aseptic meningitis such as human immunodeficiency virus and syphilis if the viral PCR panel was negative. The benefit of PCR testing in aseptic meningitis in adults in reducing LOS and antibiotic use is unclear. The reasons for unnecessary aciclovir use in meningitis syndromes require further assessment.

Etiology of acute meningitis and encephalitis from hospital-based surveillance in South Kazakhstan oblast, February 2017-January 2018

Encephalitis and meningitis (EM) are severe infections of the central nervous system associated with high morbidity and mortality. The etiology of EM in Kazakhstan is not clearly defined, so from February 1, 2017 to January 31, 2018 we conducted hospital-based syndromic surveillance for EM at the Shymkent City Hospital, in the South Kazakhstan region. All consenting inpatients meeting a standard case definition were enrolled. Blood and cerebrospinal fluid (CSF) samples were collected for bacterial culture, and CSF samples were additionally tested by PCR for four bacterial species and three viruses using a cascading algorithm. We enrolled 556 patients. Of these, 494 were of viral etiology (including 4 probable rabies cases), 37 were of bacterial etiology, 19 were of unknown etiology and 6 were not tested. The most commonly identified pathogens included enterovirus (73%, n = 406 cases), herpes simplex virus (12.8%, n = 71), and Neisseria meningitidis (3.8%, n = 21). The incidence rates (IRs) for enteroviral and meningococcal EM were found to be 14.5 and 0.7 per 100,000 persons, respectively. The IR for bacterial EM using both PCR and culture results was 3–5 times higher compared to culture-only results. Antibacterial medicines were used to treat 97.2% (480/494) of virus-associated EM. Incorporation of PCR into routine laboratory diagnostics of EM improves diagnosis, pathogen identification, ensures IRs are not underestimated, and can help avoid unnecessary antibacterial treatment.

Adenovirus cerebellitis in an immunocompetent 2-year-old girl

Acute cerebellitis (AC) is a principal cause of acute cerebellar dysfunction in previously well children. Although the condition is usually benign, fatal complications include obstructive hydrocephalus and brainstem compression; therefore, prompt accurate diagnosis is vital. ¹ There are various pathogens reported in the literature as aetiological agents of AC; however, adenovirus is very rarely mentioned, with only one previous case report in the literature to the best of our knowledge. ² This case demonstrates the importance of recognising adenovirus as a cause of AC, particularly when preceded by a respiratory tract infection in the paediatric age group. Furthermore, we highlight the role of early neuroimaging in differentiating AC from other causes of acute cerebellar dysfunction, which require different management. Our patient made a full recovery with no long-term deficits demonstrating that comprehensive investigation and consideration of atypical pathogens in the context of AC is vital in securing a favourable outcome.

Syndrome Evaluation System for Simultaneous Detection Pathogens Causing Acute Encephalitic Syndrome in India, Part-1: Development and Standardization of the Assay

A large number of organisms are known to cause acute encephalitic syndrome (AES). A number of diagnostic tests have to be performed in order to arrive at a probable pathogen causing AES thus making it a very time consuming, laborious and expensive. The problem is further compounded by the lack of availability of sufficient volume of Cerebrospinal fluid (CSF). Thus, there is an urgent need of a diagnostic tool for the simultaneous detection of all probable pathogens responsible for causing AES. Here we report the development of a novel diagnostic method, Syndrome Evaluation System (SES) for the simultaneous detection of 22 pathogens including RNA and DNA Viruses, bacteria, fungi, and parasite all endemic to India and Southeast Asia in a single sample using a novel multiplexing strategy. Syndrome Evaluation System (SES) involves isolation of nucleic acid, multiplex amplification of the DNA, and cDNA followed by identification of the amplified product by sequence specific hybridization on SES platform with the final read out being a visually recordable colored signal. The total time required to carry out this diagnostic procedure is 7 h. The SES was standardized using the commercially available vaccines, panels and cell culture grown quantified viruses/bacteria/fungi. The limit of detection (LOD) of SES ranged between 0.1 and 50 viral particles per ml of CSF and 100 to 200 bacterial cells or 5 parasites per ml of CSF, along with 100% specificity. Precision studies carried out as per the Clinical Laboratory Improvement Amendments (CLIA) guidelines, using two concentrations of each pathogen one the LOD and the other double the LOD, clearly demonstrated, that inter/intra assay variability was within the limits prescribed by the guidelines. SES is a rapid molecular diagnostic tool for simultaneous identification of 22 etiological agents of AES encountered both in sporadic and outbreak settings.

Fifteen-minute consultation: enterovirus meningitis and encephalitis-when can we stop the antibiotics?

Enterovirus (EV) is the most common cause of aseptic meningitis and has a benign course, unlike EV encephalitis, which can result in long-term neurological sequelae. There are no active treatments or prophylactic agents, and management is purely supportive. Obtaining an EV-positive cerebrospinal fluid result usually allows antimicrobial treatment to be stopped. This review will answer some of the common questions surrounding EV meningitis/encephalitis.

Evaluation of two (semi-)nested VP1 based-PCRs for typing enteroviruses directly from cerebral spinal fluid samples

Human enteroviruses (EVs) are the leading cause of CNS-associated disease in childhood. Identification of the EV types that patients are infected with is essential for monitoring outbreaks, the emergence of new types or variants, epidemiological surveillance and contributes to patient management. Rapid and sensitive molecular detection methods are frequently used to detect EVs/HPeVs directly from CSF. This requires that sensitive EV typing methods from CSF material need to be developed. In the present study two nested PCR-based typing assays were evaluated. The performance of the EV-A and -B specific nested PCR protocol and the Codehop-based PCR protocol were analyzed with several TCID(50)-titrated EV-A to D strains and 22 EV positive CSF samples. The EV-A and -B protocol was found to be more sensitive than the Codehop protocol. The Codehop protocol showed a high degree of aspecific amplification products when run on a gel, and required additional gel purification. The detection limit of the two protocols varied between the types, ranging from 0.1TCID(50)/mL sample to 10(6)TCID(50)/mL sample. From the 22 EV positive CSF samples, 15 (68%) samples were typed using either protocol. All samples were characterized as members of species B (E30 (9), CAV9 (2), E6 (1), E11 (1), E21 (1), E25 (1)). Three samples (E30 (2) and E25 (1)) could only be typed using the EV-B protocol. In this study, selected EV strains could be typed using both assays at low virus concentrations, typically found in CSF. However, the EV-A and -B protocol was more sensitive than the Codehop protocol for primary typing of CSF samples.

Prediction of Lyme meningitis based on a logistic regression model using clinical and cerebrospinal fluid analysis: a European study

BACKGROUND

A prediction model based on clinical and cerebrospinal fluid (CSF) analysis has been proposed for the differentiation of Lyme meningitis (LM) from non-Lyme aseptic meningitis (NLAM) in the United States. No similar model has ever been proposed for European patients. The objective of our study was to develop a prediction model to differentiate LM from NLAM based on clinical and CSF biologic data.

METHODS

The medical charts of all children older than 2 years of age admitted to our hospital from 1996 through 2006 with a definite diagnosis of LM were analyzed and compared retrospectively with those having a diagnosis of NLAM. Chart review included the duration of symptoms, the presence of cranial neuropathy, and CSF analysis.

RESULTS

A total of 93 patients were included (LM: 26 patients; NLAM: 67 patients) in the study. Patients with LM had statistically more frequent cranial neuropathy (73% vs. 4%), displayed a longer duration of symptoms before admission (8.8 vs. 1.8 days), had a higher CSF protein (71 vs. 38 mg/d), and had a lower percentage of neutrophil cells in the CSF (3.4% vs. 51%) than patients with NLAM. A predicted probability was derived from these 4 variables. At a cutoff point of >0.432, the model had a negative predictive value of 100% and a positive predictive value of 92.3%, with a sensitivity of 100% and a specificity of 97%.

CONCLUSIONS

We report the first European prediction model for LM. Owing to its high negative predictive value, this model may assist physicians in managing aseptic meningitis (AM) while awaiting serologic tests, especially in Lyme endemic regions.

Comparison of cell culture with RT-PCR for enterovirus detection in stool specimens from patients with acute flaccid paralysis

Since October 2000, Iran has been declared polio-free by the World Health Organization (WHO). Despite the fact that poliomyelitis caused by polioviruses has been eliminated from Iran, the number of acute flaccid paralysis (AFP) cases has not been reduced. Therefore, it is of great importance to investigate the other viral agents that may cause AFP (mainly nonpolio enteroviruses, which play a significant role in the etiology of neurological syndromes). Some enteroviruses do not grow in the conventional cell lines that are being used for enterovirus detection. Furthermore, the virus titer is an important factor in the sensitivity of cell culture to detect the virus. The fact that cell culture is a time-consuming procedure is another reason to find a more practical method for enterovirus detection. Therefore, a more sensitive and rapid method should be used to detect enteroviruses as efficiently as possible in the stool specimens of AFP cases. The aim of this study was to evaluate cell culture and RT-PCR in enterovirus detection. Findings have shown that RT-PCR can increase the rate of nonpolio enterovirus detection by up to 10% in comparison with cell culture. Also, the rapid detection of enteroviruses by RT-PCR can decrease both the unnecessary use of antibiotics and the costs in clinical practice. For this reason, we find that RT-PCR is a more practical technique for enterovirus detection.

Role of cell culture for virus detection in the age of technology

Viral disease diagnosis has traditionally relied on the isolation of viral pathogens in cell cultures. Although this approach is often slow and requires considerable technical expertise, it has been regarded for decades as the "gold standard" for the laboratory diagnosis of viral disease. With the development of nonculture methods for the rapid detection of viral antigens and/or nucleic acids, the usefulness of viral culture has been questioned. This review describes advances in cell culture-based viral diagnostic products and techniques, including the use of newer cell culture formats, cryopreserved cell cultures, centrifugation-enhanced inoculation, precytopathogenic effect detection, cocultivated cell cultures, and transgenic cell lines. All of these contribute to more efficient and less technically demanding viral detection in cell culture. Although most laboratories combine various culture and nonculture approaches to optimize viral disease diagnosis, virus isolation in cell culture remains a useful approach, especially when a viable isolate is needed, if viable and nonviable virus must be differentiated, when infection is not characteristic of any single virus (i.e., when testing for only one virus is not sufficient), and when available culture-based methods can provide a result in a more timely fashion than molecular methods.

Combining multiplex reverse transcription-PCR and a diagnostic microarray to detect and differentiate enterovirus 71 and coxsackievirus A16

Cluster A enteroviruses, including enterovirus 71 (EV71) and coxsackievirus A16 (CA16), are known to cause hand-foot-and-mouth disease (HFMD). Despite the close genetic relationship between these two viruses, EV71 is generally known to be a more perpetuating pathogen involved in severe clinical manifestations and deaths. While the serotyping of enteroviruses is mostly done by conventional immunological methods, many clinical isolates remain unclassifiable due to the limited number of antibodies against enterovirus surface proteins. Array-based assays are able to detect several serotypes with high accuracy. We combined an enterovirus microarray with multiplex reverse transcription-PCR to try to develop a method of sensitively and accurately detecting and differentiating EV71 and CA16. In an effort to design serotype-specific probes for detection of the virus, we first did an elaborate bioinformatic analysis of the sequence database derived from different enterovirus serotypes. We then constructed a microarray using 60-mer degenerate oligonucleotide probes covalently bound to array slides. Using this enterovirus microarray to study 144 clinical specimens from patients infected with HFMD or suspected to have HFMD, we found that it had a diagnostic accuracy of 92.0% for EV71 and 95.8% for CA16. Diagnostic accuracy for other enteroviruses (non-EV71 or -CA16) was 92.0%. All specimens were analyzed in parallel by real-time PCR and subsequently confirmed by neutralization tests. This highly sensitive array-based assay may become a useful alternative in clinical diagnostics of EV71 and CA16.

Clinical and diagnostic findings of an echovirus meningitis outbreak in the north west of England

INTRODUCTION

An outbreak of echovirus meningitis occurred in the north west of England in 2001. This paper reviewed the clinical features and the role of different diagnostic methods.

METHODS

This was a prospective study of adults admitted to a regional infectious disease unit with a probable diagnosis of meningitis, March to August 2001.

RESULTS

Half the 40 cases were male; median age was 28 (range 16-51) years. Fifteen of 38 (39.5%) were smokers, and 20 of 24 (83.3%) had close contact with children. Median (range) duration of symptoms was 1.1 (0.25-7) days. Symptoms included headache (100%), photophobia (87.5%), and nausea (67.5%), and severity ranged from minimal signs to those consistent with a meningoencephalitis. The diagnosis was confirmed virologically in 29 of 40 (72%); echovirus 30 was isolated from six. Cerebrospinal fluid (CSF) enterovirus polymerase chain reaction (PCR) was positive in 26 of 32 (81%), and CSF virus culture in 3 of 16 (19%). Thirty one per cent of CSF samples had a neutrophil predominance, and 3 of 29 (10%) virologically confirmed cases had normal CSF microscopy and biochemistry.

CONCLUSION

CSF microscopy may be normal or suggest bacterial meningitis in a substantial minority of cases of echovirus meningitis. CSF PCR for enterovirus seems to be more sensitive than virus culture of CSF, although PCR does not yield information on circulating virus type. Early and accurate diagnosis could reduce both use of parenteral antibiotics and length of hospital stay with both morbidity and cost implications. Close contact with children may be a risk factor, particularly if good hygiene measures are not practised.

Nucleotide analysis and phylogenetic study of the homology boundaries of coxsackie A and B viruses

Modern molecular methods use VP1 coding region as a target for RT-PCR assays followed by sequencing, in order to identify new untyped enteroviruses' strains. In the present study, two different genomic portions of VP1 and the full length of 2A coding region of 53 clinical isolates, mostly belonging to HEV-B species, were amplified and sequenced. Nucleotide analysis of the produced sequences revealed that the values that define an unknown strains serotype vary according to the serotype and the specific part of VP1, which is investigated. The correlation, however, with the serotype was affirmed in both VP1 portions that were studied, as well as in the first 20 bases of 2A region. In the rest of 2A, no correlation with the serotype and disruption of monophyly was observed. Phylogenetic analysis of the same sequences confirmed, in most cases, the results of the nucleotide analysis.

Development and evaluation of a real-time RT-PCR assay on the LightCycler for the rapid detection of enterovirus in cerebrospinal fluid specimens

BACKGROUND

Detection of enteroviral nucleic acid in cerebrospinal fluid (CSF) specimens has been demonstrated to improve the management of patients with aseptic meningitis.

OBJECTIVE

To develop on the LightCycler (LC) instrument a real-time RT-PCR assay based on TaqMan technology for the detection of enteroviruses (EV) in cerebrospinal fluid (CSF) specimens.

STUDY DESIGN

After evaluation of the analytical performances, seventy-four CSF samples collected prospectively from patients who have been suspected for a clinical diagnosis of meningitis were evaluated by two LC real-time RT-PCR assays and one conventional RT-PCR assay.

RESULTS

Our assay detected all 30 different EV species tested, whereas no reactivity was observed with other neurotropic viruses. The analytical sensitivity of both LC RT-PCR real-time assays was 1 TCID50 for LC one-step and two-step RT-PCR assays. Results for LC one-step and LC two-step RT-PCR were compared to results of the conventional RT-PCR: of the 74 CSF specimens tested, 11 were positive and 56 were negative by all methods. Four other specimens were positive for EV by at least two of the methods (including the LC two-step RT-PCR and the conventional RT-PCR), two other CSF specimens were positive by the LC two-step RT-PCR assay only, and another one CSF specimen was positive by the LC one-step RT-PCR assay only. No CSF specimens were negative by the LC two-step RT-PCR assay and positive by the conventional RT-PCR assay. The sensitivity, specificity, positive and negative predictive values of both LC RT-PCR assays by using conventional RT-PCR as the "gold standard" were, respectively, 73.3, 98.3, 91.7, 93.5% for the LC one-step RT-PCR and 100, 96.6, 88.2, 100% for the LC two-step RT-PCR. There was substantial agreement between the three assays (k=0.80).

CONCLUSIONS

The LC two-step RT-PCR assay is a rapid, sensitive and reliable method which can be routinely performed with CSF samples for diagnosis of EV infection and is an important improvement for optimal patient management.

[Neuromeningeal enterovirus infections in Tunisia: epidemiology, clinical presentation, and outcome of 26 pediatric cases]

Non-polio enteroviruses are the most common identified cause of viral neuromeningeal infections following the introduction of the mumps and polio vaccines.

OBJECTIVE

The aim of this study was to describe the epidemiology, clinical presentation, and the outcome of enteroviral infections of the CNS.

METHOD AND PATIENTS

We performed a prospective study on 41 children admitted for viral neuromeningeal infections in the pediatric department of Monastir between December 2001 and November 2002. Enteroviruses were detected from cerebrospinal fluid by RT-PCR.

RESULTS

This study showed that enteroviruses were responsible for 63.4% of the infections. The mean age of patients was 6.1 years. Aseptic meningitis was diagnosed in 14 cases and encephalitis in 10. The most frequent symptom was fever (61.5%), followed by seizures (42.3%), and confusion (23%). On follow-up, all patients with meningitis had recovered without sequels. Neurological complications in patients with encephalitis were epilepsy (3 cases), cerebral palsy (2 cases), and mental retardation (1 case).

CONCLUSION

This study confirmed that enteroviruses were the most common cause of viral infections of the CNS. Common use of RT-PCR can have a significant impact on the outcome of patients with enterovirus infections.

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.

Detection of enterovirus RNA in cerebrospinal fluid (CSF) using NucliSens EasyQ Enterovirus assay

Rapid detection of enterovirus (EV) infections is essential in the management of aseptic meningitis. Molecular approaches have opened the way to such rapid, but also specific and sensitive, diagnostic tests. The aim of this study was to compare the performance of the CE marked NucliSens EasyQ Enterovirus assay with an in-house two-step RT-PCR assay using cerebrospinal fluid (CSF) and throat swab samples. In addition, specificity was tested with clinical isolates positive for viruses with clinical importance in CSF samples. For nucleic acid extraction, the NucliSens miniMAG and NucliSens magnetic extraction reagents were used. Subsequently real-time nucleic acid sequence-based amplification (NASBA) RNA amplification was performed using NucliSens EasyQ basic kit reagents and NucliSens EasyQ Enterovirus reagents. An EV-specific internal homologous control (IC) RNA was used to monitor the entire NucliSens EasyQ procedure at the individual sample level. No IC but an external inhibition control was available for the RT-PCR method. For the NucliSens EasyQ procedure, amplification and real-time detection reactions were carried out in the NucliSens EasyQ analyzer. The real-time NASBA enterovirus detection was based on NASBA amplification and real-time molecular beacon technology. Data were analyzed using the manufacturer's software on the NucliSens EasyQ analyzer. For the in-house assay, RT-PCR amplicons were detected using agarose gel analysis. The analysis of clinical samples positive for HSV-1, HSV-2, adenovirus, CMV, VZV, mumps and rhinovirus were all negative by NucliSens EasyQ Enterovirus assay. Three rhinovirus samples were, however, strongly positive in RT-PCR. A total of 141 clinical samples were retrospectively tested, including 126 cerebrospinal fluid (CSF) samples and 15 throat swabs. The 91 CSF samples were negative by both methods, 31 CSF samples and 14 throat swab samples were positive by both methods. The four CSF samples were positive by RT-PCR only. One throat swab sample was negative in NucliSens EasyQ but positive in RT-PCR. The sensitivity and specificity of both methods seem to be more or less comparable. However, the in-house RT-PCR assay appears to amplify some rhinovirus strains and should therefore not be used for throat swab samples. NucliSens EasyQ Enterovirus assay gave more invalid results than the in-house RT-PCR, which is obvious taken into account the difference in quality control between the CE marked NucliSens EasyQ Enterovirus assay and the in-house enterovirus assay. The NucliSens EasyQ procedure can be completed within 5h versus 9.5h for the RT-PCR. NucliSens EasyQ Enterovirus assay showed to be a standardized, rapid, specific, sensitive and reliable procedure for the detection of enterovirus RNA.

A comparative amplification of five different genomic regions on Coxsackie A and B viruses. Implications in clinical diagnostics

Modern molecular approaches in Human Enterovirus detection rely on the designing of generic and often degenerate primers in order to amplify specific sequences within the enterovirus genome. In the present study a comparative application of primer sets targeting 5'UTR, the VP1 region, the 3D region as well as a long genomic fragment including the 3'end of VP1, the full length of 2A and 2B, and the 5' moiety of the 2C-coding region was attempted, in order to evaluate their specificity and suitability. The best amplification results from the investigation of 21 CAV reference strains, all six CBV reference strains and 44 clinical strains varying in origin and time of isolation, arose using primer sets 292-222 and UC53-UG52. Based on the above results we conclude that some of the published protocols need to be improved so as to fulfill the demands of an accurate detection and typing of Coxsackie A and B viruses. Contrarily, two of the protocols applied were proved to be more accurate in terms of specificity and general applicability, suggesting that RT-PCR followed by a simple RFLP assay in the case of primer pair UC53-UG52 or by sequencing and sequence analysis in the case of primer set 292-222 should constitute alternative means of modern typing and diagnostics against conventional immunological classification methods.

Amplification of Echoviruses genomic regions by different RT-PCR protocols--a comparative study

In the present report, the results of a comparative study in the detection of all Echoviruses reference strains as well as of 38 clinical isolates are presented. Using RT-PCR with already published primer pairs (UG(52)-UC(53), 292-222, 012-011 and EUG2a, 2b, 2c-EUC2) from the 5'UTR, the VP1 region as well as a long genomic fragment including the VP1 3' end, the entire coding sequence of 2A, 2B, and the 5' moiety of the 2C-coding region amplification was effective with all reference and clinical Echovirus isolates with primer pair UG(52)-UC(53) while with 292-222 and 012-011 were amplified 27/28 reference Echovirus strains and all clinical isolates. As far as EUG2a,2b,2c-EUC2 is concerned, the RT-PCR gave a positive result for 26/28 reference Echovirus strains and 34/38 clinical isolates. The sequence analysis of a large part of the 5'UTR has revealed that there is no correlation between 5'UTR identity and the currently recognized human enterovirus species. It has been suggested that part of VP1 coding sequence would correlate well with serotype since a number of important neutralization epitopes, as well as receptor recognition sequences, lie within the VP1 coding sequence. Therefore, UG(52)-UC(53) and 292-222 primer pairs seem to be the most appropriate for Echovirus detection and, moreover, UG(52)-UC(53) is useful for the classification of enteroviruses into genetic clusters (sub-groups) while 292-222 for the identification of enteroviruses by amplicon sequencing.

Prospective investigation of a large outbreak of meningitis due to echovirus 30 during summer 2000 in marseilles, france

Enteroviruses (EVs) are responsible for an array of clinical diseases affecting different systems of the organism. Many cases are asymptomatic; the most severe clinical syndromes caused by EVs are due to infection of the central nervous system and present as aseptic meningitis or encephalitis. We report here a large outbreak of enteroviral meningitis that spread in Marseilles, France, during the year 2000. The dominant strain of the outbreak was genetically identified as a human echovirus 30. The study was conducted prospectively from May to December 2000, with an investigative protocol recording epidemiologic, clinical, and laboratory data. A total of 250 patients with febrile neurologic manifestations were included between May 15 and December 30, 2000. A total of 195 cerebrospinal fluid (CSF) samples, 114 throat swabs, and 85 stool specimens were processed through viral culture and resulted in respectively 117 (60%), 61 (54%), and 58 (68%) cultures positive for EV; 69/106 (65%) CSF samples tested positive for the presence of EV RNA. None of the throat swab cultures but 5 of the stool cultures in control patients were positive. One hundred thirty-nine (55.6%) patients were considered confirmed cases because they had positive culture or reverse transcription polymerase chain reaction (RT-PCR) in CSF, and 38 (15.2%) patients were considered probable cases because they had a positive throat and/or stool culture and a negative (or not performed) procedure in CSF. The 177 confirmed and probable cases were not significantly different from the remaining 73 patients in terms of age distribution and epidemiologic, clinical, and biologic characteristics. The median age was 18.4 years (range, 15 d to 84 yr), and 92% of patients were younger than 40 years old. The male:female sex ratio was 1.8:1. We found no evidence of cases spread in nosocomial, household, or institutional settings, or limited community spread. All patients were immunocompetent except 4 adults. Meningoencephalitis represented 5.6% of cases. All but 3 of the 177 patients had a good outcome without sequelae. Two immunocompetent adults with meningoencephalitis had neurologic sequelae and an immunosuppressed adult had a fatal outcome. Upper respiratory symptoms were noted in 18.5% of patients, diarrhea in 11.5%, various types of rash in 4.5%, and myalgia in 3.8%. In CSF, white cell count was elevated in 90% of cases, with a percentage of neutrophils >50% in 55% of cases. Protein level was increased in 43% of cases. In blood, C-reactive protein was elevated in 67% of cases. Other blood parameters were unremarkable. Clinical and laboratory features did not differ from those related to other pathogens that caused meningitis and meningoencephalitis. Hence, unnecessary treatment for other infections is frequently instituted during EV infections. Virologic diagnosis is important to distinguish between EV and other treatable bacterial and viral diseases.

Laboratory diagnosis of enteroviral infections of the central nervous system by using a nested RT-polymerase chain reaction (PCR) assay

Enteroviruses are the most common pathogens identified in infants hospitalized for suspected aseptic meningitis. Rapid detection of enterovirus infection is essential in taking the decision for treatment with antiviral agents and applying infection control measures in hospitalized pediatric patients. The purpose of this study was to compare the results of conventional virus isolation with those of enteroviral RNA detection by reverse transcription (RT)-PCR method in identical specimens from cases of suspected aseptic meningitis. Cerebrospinal fluid (CSF) samples were collected for viral examination from 68 pediatric patients with suspected aseptic meningitis from 1999 to 2002. These samples were inoculated in HeLa, Hep-2 and RD cell culture. The viral RNA was investigated by in-house RT-PCR method. The isolated viruses were typed by neutralization test. 36 of the 68 specimens were detected to be enterovirus positive by culture method, while 43 of them yielded positive results when RT-PCR method is used. Discrepancies occurred between the two methods in 15 specimens. While 11 specimens were positive by RT-PCR, these are found to be culture-negative. The isolated viruses were typed as Echovirus 30 (n: 30), Group B coxsackievirus (n: 5) and one isolate could not be typed by neutralization. Because of higher sensitivity and rapidity of RT-PCR, it is superior (p = 0.016) to virus culture of CSF for the diagnosis of enterovirus meningitis. Although the clinical usefulness of viral culture from CSF is limited, the final laboratory identification needs cultural techniques.

Genetic diversity of echovirus 30 during a meningitis outbreak, demonstrated by direct molecular typing from cerebrospinal fluid

Echovirus 30 is one of the enterovirus serotypes isolated most frequently in meningitis cases. The genetic diversity of echovirus 30 was investigated in patients hospitalised during an outbreak in 2000 in Clermont-Ferrand, France. A nested reverse transcription-PCR (RT-PCR) assay was developed for qualitative analysis of the echovirus 30 VP1 encoding sequence directly from cerebrospinal fluid. The viral sequences obtained for 22 patients were compared with those of virus isolates obtained from nine patients with echovirus 30 meningitis admitted to hospital in 1996-1997 and with echovirus 30 sequences from international databases. In 2000, meningitis cases were caused by two virus variants (C3 and C4) distinct genetically from the other two variants (C1 and C2) identified during the period 1996-1997. A detailed phylogenetic analysis established that the C1, C2, and C3 variants had close relatives among viruses previously identified in other geographical areas. The C4 variant had not been described earlier. The genomic differences observed between the four echovirus 30 variants arose at synonymous sites indicating that the viruses shared similar antigenic sites in the VP1 encoding sequence. Overall, these observations suggest wide circulation of different echovirus 30 variants and periodic importation of new viruses. The apparent displacement observed between virus variants did not result from a selective advantage caused by antigenic variation.

[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.

Rapid detection of enterovirus infection by automated RNA extraction and real-time fluorescence PCR

BACKGROUND

Molecular detection has been shown to be superior to tissue culture for the detection of enteroviruses in cerebrospinal fluid (CSF) specimens.

OBJECTIVES

In this study, a qualitative molecular assay based on automated RNA extraction with the MagNA Pure LC and real-time PCR on the LightCycler (LC) instrument was evaluated and compared with an in-house molecular assay.

STUDY DESIGN

A total of 109 CSF specimens were investigated for the comparative study. The detection limit of the new molecular assay was determined with 10-fold dilutions of two enterovirus strains and with the Third European Union Concerted Action Enterovirus Proficiency Panel.

RESULTS

With the enterovirus strains, the detection limit of the LC assay was found to be 0.1 TCID(50) (50% tissue culture infective dose). When samples of the Third European Union Concerted Action Enterovirus Proficiency Panel were tested, both molecular assays gave identical results to the expected results, which were based upon the results of three reference laboratories using a total of four different molecular methods before distribution of the panel. When clinical specimens were tested, there was a correlation between the LC assay and the in-house assay in 105 of 109 cerebrospinal fluids.

CONCLUSIONS

The new molecular assay allows rapid detection of enterovirus RNA in CSF. It was found to be labor saving and showed sufficient sensitivity.

Use of internal standard RNA molecules for the RT-PCR amplification of the faeces-borne RNA viruses

The diagnostic system based on reverse transcription (RT)-PCR has been used widely for the detection of viral genomes of faecal-borne RNA viruses. However, faecal specimens often produce both false positive and false negative results. Therefore, there is a need for a diagnosis procedure that can control for 'false-results'. In this study, an internal standard RNA that can serve as a non-competitive positive template was developed and used directly to detect faecal-borne RNA viruses without noticeable competitive inhibition of the target viral genome. These results suggest that the internal standard RNA is a useful standard molecule when undertaking diagnostic qualitative RT-PCR procedures for enteroviruses and related faecal-borne RNA viruses.

Evaluation of a rapid real-time RT-PCR assay for detection of enterovirus RNA in cerebrospinal fluid specimens

BACKGROUND

We previously described the characteristics of a single-tube real-time enterovirus reverse transcriptase polymerase chain reaction (RT-PCR) assay based on a fluorogenic probe and primers directed to highly conserved sequences in the 5'-untranslated region (UTR) of the enterovirus genome.

OBJECTIVES

To evaluate the performance of the assay on a larger number of cerebrospinal fluid (CSF) specimens from patients suspected of having viral meningitis.

STUDY DESIGN

Real-time enterovirus RT-PCR and viral culture were performed on CSF specimens received from March 2000 to November 2001. Patient records were retrospectively reviewed for final clinical diagnosis.

RESULTS

From the 186 CSF specimens tested, culture was positive for enterovirus in 31 cases, whereas real-time RT-PCR detected enterovirus RNA in 45 CSF specimens. The sensitivity of real-time RT-PCR in relation to the clinical diagnosis of viral meningitis was 72.6%, whereas the sensitivity of viral culture reached only 57.4%. Enterovirus RNA was also found in a number of specimens with low leukocyte counts.

CONCLUSIONS

We confirm that the real-time enterovirus RT-PCR assay for CSF specimens is significantly more sensitive than viral culture.

Evaluation of a one-tube RT-PCR system for detection of enteroviruses

BACKGROUND

A highly sensitive PCR assay for early and rapid detection of enteroviral (EV) RNA in CSF is necessary to investigate the role of EV in acute neurological illnesses.

OBJECTIVES

To evaluate and compare two PCR protocols (Titan one-tube RT-PCR and random primed RT-PCR) for detection of enteroviral RNA in CSF.

STUDY DESIGN

The PCR protocols were evaluated for lower limit of input detection using log dilutions of five stock EV strains and an isolate of enterovirus-71 in minimum essential medium and three EV stock strains in CSF. The tests were also applied on 77 CSF samples, 46 from patients with suspected acute EV neurological illness and 31 from 'disease controls'.

RESULTS

Even though in the initial virus titration assays there was no statistically significant difference in the limit of input detection by Titan system and the random primed two-step PCR, the latter had a higher positivity rate when used on CSF samples from patients (20/46 vs. 10/46, P<0.01).

CONCLUSIONS

Random primed RT-PCR assay is superior to Titan one-tube RT-PCR for detection of EV RNA in CSF.

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.

Molecular techniques should not now replace cell culture in diagnostic virology laboratories

The value of molecular techniques for virology is not in dispute; the issue debated here is whether or not to abandon virus isolation altogether. Modern clinical virology relies on rapid virus detection for timely infection control and antiviral therapy. The role of virus isolation, inevitably a slower process as it involves replication in cell cultures, is most significant in providing epidemiological data, in the diagnosis of new or unexpected infection, and in yielding infectious virus for further study. Examples include identification of enterovirus serotypes in outbreaks, diagnosis of atypical virus infections, and provision of virus isolates for phenotypic antiviral susceptibility assays. Many viruses can be detected after overnight culture using the centrifugation-enhanced (shell vial) technique. In contrast to this established track record, the commercial development of molecular assays has been concentrated on blood-borne viruses, and standardisation of procedures for other viruses is lacking. Accreditation of molecular techniques is just beginning, and few external quality assurance schemes are available yet. In my view, it is premature to abandon routine virus isolation, although as molecular diagnosis expands, the facilities for cell culture and isolation work may become more centralised to retain expertise and to provide the range and quality of service required.

Aseptic meningitis in Germany associated with echovirus type 13

BACKGROUND

Echoviruses are the commonest cause of aseptic meningitis. Echovirus type 13 which has not been isolated in Germany over a long period of time was the predominant enterovirus serotype associated with different local outbreaks of aseptic meningitis in Germany in 2000.

METHODS

Virus isolation was performed from cerebrospinal fluid and stools. In order to study the genetic relationship of echovirus type 13 isolates, sequence analysis of a part of VP1 (~300 nt) was carried out. Isolates from different geographic regions were compared to each other as well as to elder viruses (prototype strain from 1953, four isolates from 1965-1986).

RESULTS

Overall, 55 isolates of echovirus type 13 were obtained from different parts of Germany. It was shown that the new isolated strains have a very high degree of homology on the nucleotide level (> 98%)) but differ significantly from the old strains (76-85%).

CONCLUSIONS

a) Rare enterovirus serotypes can cause serious illness.b) The molecular drift has also been shown for other enterovirus serotypes.

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.

Evaluation of enterovirus serological tests IgM-EIA and complement fixation in patients with meningitis, confirmed by detection of enteroviral RNA by RT-PCR in cerebrospinal fluid

An enzyme immunoassay (EIA) for detection of anti-enterovirus IgM antibodies was compared with complement fixation test in 43 patients with confirmed enterovirus meningitis by RT-PCR of cerebrospinal fluids (CSF). In 34% of patients with enterovirus meningitis, IgM antibodies could be found, whereas complement fixation tests were positive in only 20%. The specificity was determined with sera of 105 patients with non-enterovirus meningitis. Specificity of IgM EIA and of complement fixation was 94% and 85%, respectively. In four patients with meningitis but without enterovirus detection in CSF, RT-PCR and virus isolation from stools were positive. In three of these patients, IgM antibodies were detected, giving a strong indication of an enterovirus-associated disease. Because of the high specificity of IgM EIA, diagnosis of enterovirus-associated diseases can be carried out in a single serum sample, whereas by complement fixation tests, only fourfold increases in antibody titres in paired sera indicate an acute infection. The application of IgM EIA is especially important in cases of meningitis when CSF samples are not available and for diagnosis of enterovirus diseases with other clinical symptoms such as fever, enteritis, and hand-foot-and-mouth disease.

Genomic variations in echovirus 30 persistent isolates recovered from a chronically infected immunodeficient child and comparison with the reference strain

Seven sequential isolates of echovirus type 30 (EV30) were recovered over 22 months from a child with severe combined immune deficiency syndrome. The nucleotide sequences of the 5' halves of the genomes (4,400 nucleotides) of the first (S1) and last (S7) isolates were determined and compared with that of the EV30 Bastianni reference strain, also determined in this study. In genome regions P1 and P2, 101 variations were identified between the two isolates. Synonymous differences far outnumbered nonsynonymous differences. Amino acid changes affected both capsid and nonstructural polypeptides (particularly 2B). The VP1 nucleotide sequences of the seven isolates were determined to analyze genome evolution during the chronic infection. In the phylogenetic tree, the seven isolates were directly related to the prototype strain in an individual monophyletic group, strongly suggesting that the chronic infection in the child arose from a single persistent EV30 isolate. Four lineages were observed in the persistent isolates. Isolates S2, S4, S5, and S6 were close relatives of one another, whereas isolates S1 and S3 formed individual lineages. Isolate S7, distantly related to all other isolates, formed the fourth lineage. These findings suggest the quasispecies nature of the genomes of the seven sequential EV30 isolates. Grouping of persistent isolates on the basis of replicative capacities was consistent with phylogenetic relationships. Overall, the results indicate that genetically related EV30 variants with different replicative capacities coexisted in a carrier state, probably in the gastrointestinal tract, during the infection of the child.

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.

Cerebrospinal fluid testing for the diagnosis of central nervous system infection

The central nervous system (CNS) is susceptible to bacterial, viral, and fungal infections, and prion diseases. Examination of the cerebrospinal fluid (CSF) is crucial in diagnosing these infections. Cerebrospinal tests may directly identify an organism and its nucleic acid and surface constituents by culture, polymerase chain reaction (PCR), or antigen detection. Alternatively, antibody to an organism may be identified in CSF by enzyme-linked immunosorbent assay (ELISA), Western blot, or complement fixation assay. This article discusses how these CSF tests are performed and addresses the sensitivity and specificity of such tests for the diagnosis of selected CNS infections.

An outbreak due to echovirus type 30 in a neonatal unit in France in 1997: usefulness of PCR diagnosis

Between February and August 1997, 53 patients with enterovirus meningitis were hospitalized in Clermont-Ferrand, France. All but one were children. Echovirus type 30 was involved in 70% of cases with identified serotype. The outbreak ceased on August 8. Two months later, a neonate was admitted to the neonatal unit with an echovirus type 30 meningitis thought to be acquired at delivery. Twenty days later a nosocomial outbreak of echovirus type 30 involving five neonates occurred. Two of them presented with meningitis and two with febrile seizure; One was asymptomatic. The retrospective examination of the maternal sera in a neutralization test, using the index case strain as a source of antigen, showed that none of the neonates was passively immunized before hospitalization. The use of genome detection in cerebrospinal fluid allowed rapid diagnosis and infection was contained by re-inforcing hygiene measures. Prospective examination of stools in the neonatal and paediatric units showed no further occurrences of the disease. No sporadic case was observed in the general population. Hence, nosocomial infections can occur a long time after an outbreak in the general population; rapid diagnosis with molecular tools is useful both for a definite diagnosis in patients already hospitalized, and to act as a rapid alert, even in intervals between seasonal outbreaks.

Multicenter quality assessment of PCR methods for detection of enteroviruses

We conducted a multicenter evaluation of commercial and in-house PCR methods for the detection of enteroviruses. Three coded panels of test and control RNA samples, artificial clinical specimens, and representative enterovirus serotypes were used to assess amplification methods, RNA extraction methods, and reactivities with different enterovirus serotypes. Despite several differences between PCR methods, there was good agreement, although some variation in sensitivity was observed. Most PCR methods were able to detect enterovirus RNA derived from 0.01 50% tissue culture infective dose (TCID50) and were able to detect at least 1 TCID50 of enterovirus in cerebrospinal fluid, stool, or throat swab specimens. Most were also able to detect a wide range of enterovirus serotypes, although serotypic identification was not possible. Some laboratories experienced false-positive results due to PCR contamination, which appeared to result mainly from cross-contamination of specimens during RNA extraction. Provided that this problem is overcome, these PCR methods will prove to be a sensitive and rapid alternative to cell culture for the diagnosis of enterovirus infection.