Common and new acyclovir resistant herpes simplex virus-1 mutants causing bilateral recurrent herpetic keratitis in an immunocompetent patient.

We investigated thymidine kinase (tk) mutants isolated during multiple episodes of recurrent bilateral acyclovir resistant herpes simplex keratitis in an immunocompetent patient. From one eye, we found a single guanine insertion, previously shown to greatly reduce TK expression, and from the other, a previously unidentified substitution, which genetic experiments confirmed confers drug resistance. The substitution, although distant from substrate binding sites, reduced thymidine phosphorylation 10-20-fold, and acyclovir phosphorylation >100-fold. This phenotype should permit reactivation from latency to cause recurrent disease. The results may have implications for the prevalence and prevention of acyclovir resistance in patients with herpes simplex keratitis.

Neurological manifestations of influenza infection in children and adults: results of a National British Surveillance Study.

BACKGROUND: The emergence of influenza A(H1N1) 2009 was met with increased reports of associated neurological manifestations. We aimed to describe neurological manifestations of influenza in adults and children in the United Kingdom that presented at this time. METHODS: A 2-year surveillance study was undertaken through the British adult and pediatric neurological surveillance units from February 2011. Patients were included if they met clinical case definitions within 1 month of proven influenza infection. RESULTS: Twenty-five cases were identified: 21 (84%) in children and 4 (16%) in adults. Six (29%) children had preexisting neurological disorders. Polymerase chain reaction of respiratory secretions identified influenza A in 21 (81%; 20 of which [95%] were H1N1) and influenza B in 4 (15%). Twelve children had encephalopathy (1 with movement disorder), 8 had encephalitis, and 1 had meningoencephalitis. Two adults had encephalopathy with movement disorder, 1 had encephalitis, and 1 had Guillain-Barré syndrome. Seven individuals (6 children) had specific acute encephalopathy syndromes (4 acute necrotizing encephalopathy, 1 acute infantile encephalopathy predominantly affecting the frontal lobes, 1 hemorrhagic shock and encephalopathy, 1 acute hemorrhagic leukoencephalopathy). Twenty (80%) required intensive care, 17 (68%) had poor outcome, and 4 (16%) died. CONCLUSIONS: This surveillance study described a cohort of adults and children with neurological manifestations of influenza. The majority were due to H1N1. More children than adults were identified; many children had specific encephalopathy syndromes with poor outcomes. None had been vaccinated, although 8 (32%) had indications for this. A modified classification system is proposed based on our data and the increasing spectrum of recognized acute encephalopathy syndromes.

Improving the diagnosis of central nervous system infections in adults through introduction of a simple lumbar puncture pack.

BACKGROUND: Acute central nervous system (CNS) infections, such as meningitis and encephalitis, are neurological emergencies for which accurate diagnosis and prompt treatment improve the outcome. Analysis of the cerebrospinal fluid (CSF) obtained at lumbar puncture (LP) is pivotal to establishing the diagnosis and guiding management. PCR analysis of the CSF is an important method to identify the pathogen. However, recent studies have demonstrated that many patients have inadequate CSF sample collection and analysis. AIMS: To increase the proportion of patients having an LP for a suspected CNS infection for whom the appropriate samples are taken. Secondary aims included to increase the proportion of patients for whom a pathogen was identified. METHODS: The authors developed an LP pack for patients with a suspected CNS infection. They also assessed its impact on diagnosis by comparing practice 6 months before and after its introduction to the medical admissions unit of a large inner city teaching hospital. RESULTS: The authors found that the LP pack reduced major errors in CSF sample collection and improved the diagnosis of acute CNS infections; among those patients who had a CSF pleocytosis, the proportion with a viral or bacterial pathogen identified by PCR was increased after introduction of the pack. DISCUSSION: This study has demonstrated that the introduction of a simple low-cost LP pack into a busy acute medical setting can improve the diagnosis of CNS infections and, thus, guide treatment. Further work is needed to see if these results are more widely reproducible, and to examine the clinical, health and economic impact on overall management of patients with suspected CNS infections.

Screening tests for Chlamydia trachomatis or Neisseria gonorrhoeae using the cobas 4800 PCR system do not require a second test to confirm: an audit of patients issued with equivocal results at a sexual health clinic in the Northwest of England, U.K.

OBJECTIVES: To assess the clinical utility of supplementary PCRs following a positive cobas 4800 CT/NG PCR screening test result. METHODS: Laboratory reports, for Chlamydia trachomatis or Neisseria gonorrhoeae, issued to genitourinary medicine patients between April 2010 and April 2011 were reviewed retrospectively. Positive reports were routinely confirmed by supplementary PCRs and N gonorrhoeae culture. Clinical records of patients with unconfirmed positive (equivocal) reports were retrieved to determine if the infection was confirmed by a second sample obtained at patient recall and the impact of this process on antibiotic management. RESULTS: Over 15 000 patients were tested during the study period. The prevalence of chlamydia and gonorrhoea was 972 (5.75%) and 76 (0.50%), respectively. A further 78 chlamydia and 2 gonorrhoea equivocal reports were issued. Only 56 (72%) patients with an equivocal chlamydia report returned to the clinic, and of these, only 41 (73%) gave a second sample to retest. Positive predictive value (PPV) of the PCR screening test was calculated at 98.0% and 97.5% for detection of chlamydia infection from urine and rectal swabs, respectively. Most patients accepted antibiotic treatment before their infection status had been confirmed. Prevalence of gonorrhoea infection was low but the PPV of the screening PCR in urine specimens remained high (98.75%). CONCLUSIONS: Equivocal reports introduce delays to patient management, while the risk of unnecessary antibiotic therapy appears acceptable to most patients. The cobas 4800 CT/NG PCR screening assay can achieve UK testing standards (PPV >90%) for chlamydia, and low prevalence gonorrhoea in urine without supplementary tests. A patient-led confirmation algorithm is proposed.

Viral capture sequencing detects unexpected viruses in the cerebrospinal fluid of adults with meningitis.

OBJECTIVES: Many patients with meningitis have no aetiology identified leading to unnecessary antimicrobials and prolonged hospitalisation. We used viral capture sequencing to identify possible pathogenic viruses in adults with community-acquired meningitis. METHODS: Cerebrospinal fluid (CSF) from 73 patients was tested by VirCapSeq-VERT, a probe set designed to capture viral targets using high throughput sequencing. Patients were categorised as suspected viral meningitis - CSF pleocytosis, no pathogen identified (n = 38), proven viral meningitis - CSF pleocytosis with a pathogen identified (n = 15) or not meningitis - no CSF pleocytosis (n = 20). RESULTS: VirCapSeq-VERT detected virus in the CSF of 16/38 (42%) of those with suspected viral meningitis, including twelve individual viruses. A potentially clinically relevant virus was detected in 9/16 (56%). Unexpectedly Toscana virus, rotavirus and Saffold virus were detected and assessed to be potential causative agents. CONCLUSION: VirCapSeq-VERT increases the probability of detecting a virus. Using this agnostic approach we identified Toscana virus and, for the first time in adults, rotavirus and Saffold virus, as potential causative agents in adult meningitis. Further work is needed to determine the prevalence of atypical viral candidates as well as the clinical impact of using sequencing methods in real time. This knowledge can help to reduce antimicrobial use and hospitalisations leading to both patient and health system benefits.

Detection and characterisation of human metapneumovirus from children with acute respiratory symptoms in north-west England, UK.

BACKGROUND: Human metapneumovirus (hMPV) causes a spectrum of respiratory disease ranging from trivial coryzal symptoms to fatal pneumonia, with a predilection for the very young, the immune suppressed and the frail elderly. Five distinct lineages of the virus genome have been described. OBJECTIVES: To develop and evaluate a sensitive, real-time PCR (RT-PCR) assay capable of detecting all lineages of hMPV, suitable for use in a diagnostic laboratory. STUDY DESIGN: An RT-PCR assay was developed using novel primers and dual-labelled minor-groove-binding (MGB) probes complementary to consensus sequences. The assay and two alternative assays were tested against external quality assurance (EQA) panels. 221 respiratory samples collected during 2003-2004 were screened using the new assay. hMPV positive samples were sequenced and phylogenetically analysed. RESULTS: Three genetic lineages of hMPV were detected during 2003-2004. Incidence was low (2.3%) compared to previous years. All five lineages had been present in the same community within the past 3 years. CONCLUSIONS: The new assay correctly identified more EQA samples, including those at greatest dilution, than the alternative assays and detected all five lineages. Seasonal circulation of hMPV in paediatric patients with acute respiratory symptoms is dynamic with respect to incidence and viral genotype.

Incidence, aetiology, and sequelae of viral meningitis in UK adults: a multicentre prospective observational cohort study.

BACKGROUND: Viral meningitis is increasingly recognised, but little is known about the frequency with which it occurs, or the causes and outcomes in the UK. We aimed to determine the incidence, causes, and sequelae in UK adults to improve the management of patients and assist in health service planning. METHODS: We did a multicentre prospective observational cohort study of adults with suspected meningitis at 42 hospitals across England. Nested within this study, in the National Health Service (NHS) northwest region (now part of NHS England North), was an epidemiological study. Patients were eligible if they were aged 16 years or older, had clinically suspected meningitis, and either underwent a lumbar puncture or, if lumbar puncture was contraindicated, had clinically suspected meningitis and an appropriate pathogen identified either in blood culture or on blood PCR. Individuals with ventricular devices were excluded. We calculated the incidence of viral meningitis using data from patients from the northwest region only and used these data to estimate the population-standardised number of cases in the UK. Patients self-reported quality-of-life and neuropsychological outcomes, using the EuroQol EQ-5D-3L, the 36-Item Short Form Health Survey (SF-36), and the Aldenkamp and Baker neuropsychological assessment schedule, for 1 year after admission. FINDINGS: 1126 patients were enrolled between Sept 30, 2011, and Sept 30, 2014. 638 (57%) patients had meningitis: 231 (36%) cases were viral, 99 (16%) were bacterial, and 267 (42%) had an unknown cause. 41 (6%) cases had other causes. The estimated annual incidence of viral meningitis was 2·73 per 100 000 and that of bacterial meningitis was 1·24 per 100 000. The median length of hospital stay for patients with viral meningitis was 4 days (IQR 3-7), increasing to 9 days (6-12) in those treated with antivirals. Earlier lumbar puncture resulted in more patients having a specific cause identified than did those who had a delayed lumbar puncture. Compared with the age-matched UK population, patients with viral meningitis had a mean loss of 0·2 quality-adjusted life-years (SD 0·04) in that first year. INTERPRETATION: Viruses are the most commonly identified cause of meningitis in UK adults, and lead to substantial long-term morbidity. Delays in getting a lumbar puncture and unnecessary treatment with antivirals were associated with longer hospital stays. Rapid diagnostics and rationalising treatments might reduce the burden of meningitis on health services. FUNDING: Meningitis Research Foundation and UK National Institute for Health Research.

Viral encephalitis: a clinician's guide.

The management of patients with suspected viral encephalitis has been revolutionised in recent years with improved imaging and viral diagnostics, better antiviral and immunomodulatory therapies, and enhanced neurointensive care. Despite this, disasters in patient management are sadly not uncommon. While some patients are attacked with all known antimicrobials with little thought to investigation of the cause of their illness, for others there are prolonged and inappropriate delays before treatment is started. Although viral encephalitis is relatively rare, patients with suspected central nervous system (CNS) infections, who might have viral encephalitis, are not. In addition, the increasing number of immunocompromised patients who may have viral CNS infections, plus the spread of encephalitis caused by arthropod-borne viruses, present new challenges to clinicians. This article discusses the Liverpool approach to the investigation and treatment of adults with suspected viral encephalitis, and introduces the Liverpool algorithm for investigation and treatment of immunocompetent adults with suspected viral encephalitis (available at www.liv.ac.uk/braininfections).

Using the full spectral capacity (six channels) of a real-time PCR instrument can simplify diagnostic laboratory screening and typing protocols for pandemic H1N1 influenza.

BACKGROUND: Timely reporting of influenza A virus subtype affects patient management. Real-time PCR is a rapid and sensitive method routinely used to characterise viral nucleic acid, but the full spectral capability of the instruments is not employed. OBJECTIVES: To evaluate a hexaplex real-time PCR assay (Flu-6plx assay) capable of detecting influenza A and B, hMPV, respiratory syncytial virus (RSV) and distinguishing 2008 'human' influenza A/H1 from 2009 pandemic A/H1 subtypes. METHODS: Respiratory specimens (n = 213) were tested using the Flu-6plx assay and a further four monoplex PCRs targeting hMPV, RSV, influenza A and B. The FDA-approved ProFlu ST test was used to validate the Flu-6plx PCR influenza A/H1 subtyping components. Discrepant 2009 pandemic A/H1 results were further tested using the CDC swine H1 assay. Results The Flu-6plx assay had excellent sensitivity identifying 106/106 influenza A RNA-positive samples. The ProFlu ST test was a less sensitive subtyping test, and discrepant analysis could not confirm A/H1 status for four samples resulting in Flu-6plx PCR specificities of 98% and 95% for human A/H1 and 2009 pandemic A/H1, respectively. Co-infection affected the sensitivity of the Flu-6plx PCR hMPV component whereby low-level hMPV RNA could be masked by much higher concentrations of influenza A virus RNA. CONCLUSIONS: The Flu-6plx assay is a sensitive and specific test for the universal detection of influenza A infection and determination of A/H1 subtype. Concomitant detection of influenza B, hMPV and RSV demonstrates the utility of hexaplex real-time PCRs in viral diagnostics.

Cytomegalovirus-specific CD8+ T cells do not develop in all renal transplant patients at risk of virus infection.

Cytomegalovirus (CMV) is an important pathogen in immunosuppressed renal transplant patients. At greatest risk are CMV IgG seronegative recipients (R-) of kidneys from CMV IgG seropositive donors (D+), although not all develop CMV disease. The aims of the study were to determine whether D+/R- patients who do or do not go on to develop CMV disease differ in their CD8+ T cell responses to CMV. Responses to the immunodominant NLVPMVATV peptide from the CMV structural protein pp65 in HLA-A2+ renal transplant patients were quantified using HLA tetramers/pentamers. Most D+/R+ patients had detectable tetramer+ cells while most D-/R- patients did not. Around 50% of D+/R- patients had some CD8+ tetramer+ cells and there was a strong correlation between % tetramer+ cells and the occurrence of a CMV infection post-transplantation (P<0.005). 18/41 (44%) of CMV negative patients receiving a kidney from a CMV+ donor failed to develop a detectable CMV infection, or significant numbers of tetramer+ cells. There was no relationship between CMV infection and acute cellular rejection. There was a tendency for patients who were given pre-emptive antiviral therapy to have lower levels of tetramer+ cells but this was not statistically significant. Hence the results show that CMV- patients receiving a kidney from a CMV+ donor do not inevitably acquire CMV infection. Those without CMV disease did not show any T cell response while most patients with detectable CMV developed specific CD8+ T cells.

Recurrent myositis triggered by infections: a case report.

INTRODUCTION: Recurrent myositis triggered by infections is unusual, with only one other case reporting two attacks described in the literature. CASE PRESENTATION: We report the case of a 24-year-old Caucasian woman with recurrent myositis triggered by sore throat, respiratory and urinary tract infections, over the past 18 years, up to four times a year. Myositis of this frequency and duration, apparently triggered by infections, has not been reported previously. CONCLUSION: We believe that this case adds to the understanding of myositis associated with infections being a triggered autoimmune response, and postulate that the pathogenesis in our patient is a non-specific immune response to a range of different precipitants, both bacterial and viral.