Ines Ushiro-Lumb

New point of care Chlamydia Rapid Test—bridging the gap between diagnosis and treatment: performance evaluation study

Objective To evaluate the performance of a new Chlamydia Rapid Test with vaginal swab specimens as a potential tool for chlamydia diagnosis and screening. Design Performance evaluation study. Settings A young people’s sexual health centre (site 1) and two genitourinary medicine clinics (sites 2 and 3) in the United Kingdom. Participants 1349 women aged between 16 and 54 attending one of the three clinics. Main outcome measures Sensitivity, specificity, positive predictive value, and negative predictive value of the Chlamydia Rapid Test versus polymerase chain reaction and strand displacement amplification assays; correlation between the Chlamydia Rapid Test visual signal and organism load; acceptability to participants of self collected vaginal swabs as the specimen type for Chlamydia testing. Results Polymerase chain reaction positivity rates for Chlamydia trachomatis infection were 8.4% (56/663) at site 1, 9.4% (36/385) at site 2, and 6.0% (18/301) at site 3. Compared with polymerase chain reaction assay, the resolved sensitivity, specificity, positive predictive value, and negative predictive value of the Chlamydia Rapid Test were 83.5% (91/109), 98.9% (1224/1238), 86.7% (91/105), and 98.6% (1224/1242). Compared with strand displacement amplification assay, sensitivity and specificity of the Chlamydia Rapid Test were 81.6% (40/49) and 98.3% (578/588). Organism load of self collected vaginal swabs ranged from 5.97×102 to 1.09×109 Chlamydia plasmids per swab, which correlated well with the Chlamydia Rapid Test’s visual signal (r=0.6435, P<0.0001). Most (95.9%) surveyed participants felt comfortable about collecting their own swabs. Conclusions The performance of the Chlamydia Rapid Test with self collected vaginal swabs indicates that it would be an effective same day diagnostic and screening tool for Chlamydia infection in women. The availability of Chlamydia Rapid Test results within 30 minutes allows for immediate treatment and contact tracing, potentially reducing the risks of persistent infection and onward transmission. It could also provide a simple and reliable alternative to nucleic acid amplification tests in chlamydia screening programmes.

Simple amplification-based assay: a nucleic acid-based point-of-care platform for HIV-1 testing.

BACKGROUND A new nucleic acid-based assay (simple amplification-based assay [SAMBA]) for rapid visual detection of human immunodeficiency virus-type 1 (HIV-1) by dipstick is described. The assay was designed to be simple, stable, robust, self-contained, and capable of detecting a broad spectrum of HIV-1 subtypes and recombinant forms. METHODS The performance of the SAMBA HIV-1 test (amplification and detection chemistry) was evaluated using the World Health Organization HIV-1 RNA Genotype Reference Panel, with clinical samples representing various viral subtypes and recombinant forms common in sub-Saharan Africa. Sixty-nine randomly selected and blinded clinical samples that had undergone HIV-1 genotypic resistance analyses in a large London teaching hospital were also tested. These samples included 14 different viral subtypes or recombinant forms with viral loads of 78-9.5 x 10(6) copies/mL. RESULTS The sensitivity and viral subtype coverage of the SAMBA HIV-1 test were either comparable to or better than those of the commercially available nucleic acid-based HIV-1 diagnostic tests. CONCLUSIONS The unique characteristics and competitive performance of the SAMBA HIV-1 test render it suitable for point-of-care and near-patient testing in both developed and developing countries.

Prevalence of chronic viral hepatitis in people of south Asian ethnicity living in England: the prevalence cannot necessarily be predicted from the prevalence in the country of origin

Summary.  The prevalence of hepatitis B and hepatitis C in immigrant communities is unknown. Immigrants from south Asia are common in England and elsewhere, and the burden of viral hepatitis in these communities is unknown. We aimed to determine the prevalence of viral hepatitis in immigrants from south Asia living in England, and we therefore undertook a community‐based testing project in such people at five sites in England. A total of 4998 people attending community centres were screened for viral hepatitis using oral fluid testing. The overall prevalence of anti‐hepatitis C virus (HCV) in people of south Asian origin was 1.6% but varied by country of birth being 0.4%, 0.2%, 0.6% and 2.7% in people of this ethnic group born in the UK, India, Bangladesh and Pakistan, respectively. The prevalence of hepatitis B surface antigen was 1.2%–0.2%, 0.1%, 1.5% and 1.8% in people of this ethnic group born in the UK, India, Bangladesh and Pakistan, respectively. Analysis of risk factors for HCV infection shows that people from the Pakistani Punjab and those who have immigrated recently are at increased risk of infection. Our study suggests that migrants from Pakistan are at highest risk of viral hepatitis, with those from India at low risk. As prevalence varies both by country and region of origin and over time, the prevalence in migrant communities living in western countries cannot be easily predicted from studies in the country of origin.

SAMBA HIV semiquantitative test, a new point-of-care viral-load-monitoring assay for resource-limited settings.

ABSTRACT Routine viral-load (VL) testing of HIV-infected individuals on antiretroviral therapy (ART) is used to monitor treatment efficacy. However, due to logistical challenges, implementation of VL has been difficult in resource-limited settings. The aim of this study was to evaluate the performance of the SAMBA semi-Q (simple amplification-based assay semiquantitative test for HIV-1) in London, Malawi, and Uganda. The SAMBA semi-Q can distinguish between patients with VLs above and below 1,000 copies/ml. The SAMBA semi-Q was validated with diluted clinical samples and blinded plasma samples collected from HIV-1-positive individuals. SAMBA semi-Q results were compared with results from the Roche COBAS AmpliPrep/COBAS TaqMan HIV-1 test, v2.0. Testing of 96 2- to 10-fold dilutions of four samples containing HIV-1 subtype C as well as 488 samples from patients in the United Kingdom, Malawi, and Uganda yielded an overall accuracy for the SAMBA semi-Q of 99% (95% confidence interval [CI], 93.8 to 99.9%) and 96.9% (95% CI 94.9 to 98.3%), respectively, compared to to the Roche test. Analysis of VL data from patients in Malawi and Uganda showed that the SAMBA cutoff of 1,000 copies/ml appropriately distinguished treated from untreated individuals. Furthermore, analysis of the viral loads of 232 patients on ART in Malawi and Uganda revealed similar patterns for virological control, defined as either <1,000 copies/ml (SAMBA cutoff) or <5,000 copies/ml (WHO 2010 criterion; WHO, Antiretroviral Therapy for HIV Infection in Adults and Adolescents: Recommendations for a Public Health Approach, 2010). This study suggests that the SAMBA semi-Q has adequate concurrency with the gold standard measurements for viral load. This test can allow VL monitoring of patients on ART at the point of care in resource-limited settings.

Prevalence of Hepatitis C–Related Cirrhosis in Elderly Asian Patients Infected in Childhood

BACKGROUND & AIMS Approximately 20% of hepatitis C virus (HCV) patients develop cirrhosis from infection after about 20 years. The proportion of patients developing cirrhosis for longer than 30 years after infection is unknown. Our objectives were to determine the prevalence of HCV-related cirrhosis in a population of Asian patients who were infected in childhood 20 to 80 years ago and compare this with the prevalence of cirrhosis in Caucasian patients referred to the same hospitals. METHODS Retrospective analyses were performed of all patients who had detectable HCV-RNA levels and who attended local hospitals in northeast London between 1992 and 2003. Factors implicated in the development of cirrhosis were examined by multivariable analysis. RESULTS A total of 143 adult Asian patients who had been infected with HCV for many decades were compared with 239 Caucasian patients. The prevalence of cirrhosis increased with age. Of Asian patients aged 61-80 years (n = 55) 78% had cirrhosis, whereas 25% of Caucasian patients aged 61-80 years (n = 55) had cirrhosis. Multivariable linear analysis revealed that fibrosis progression and age were similar in both groups and the difference in the prevalence of cirrhosis was not explained by any unique Asian characteristic other than prolonged infection. CONCLUSIONS The prevalence of cirrhosis in patients with chronic HCV increases with increasing duration of infection. In Asian patients infected at birth, infection for over 60 years causes cirrhosis in 71% of infected individuals. Because relationship between the severity of fibrosis and age in Asian patients is similar to that seen in Caucasian patients it is likely that similar rates of cirrhosis will be seen in other patients who are infected for more than 60 years.

Performance evaluation of a new rapid urine test for chlamydia in men: prospective cohort study

Objective To evaluate the performance of a rapid test for chlamydia with first void male urine samples as a potential tool for diagnosis and screening of chlamydial infection in men. Design Evaluation of test performance in prospective cohort study. Settings A young people’s sexual health centre (site 1) and a genitourinary medicine clinic (site 2) in the United Kingdom. Participants 1211 men aged 16-73 attending either of the two sites. Main outcome measures Sensitivity, specificity, positive predictive value, and negative predictive value of the Chlamydia Rapid Test versus polymerase chain reaction assay. Relation between the visual signal of the Chlamydia Rapid Test and organism load. Results Detection rates for Chlamydia trachomatis infection with polymerase chain reaction were 4.4% (20/454) at site 1 and 11.9% (90/757) at site 2. Compared with polymerase chain reaction assay, the resolved sensitivity, specificity, positive predictive value, and negative predictive value of the Chlamydia Rapid Test was 82.6% (90/109), 98.5% (1085/1102), 84.1% (90/107), and 98.3% (1085/1104), respectively. The organism load in first void urine samples that were positive for chlamydia ranged from 7.28×102 to 6.93×106 plasmids/ml and correlated significantly with the visual signal of the Chlamydia Rapid Test (r=0.7897, P<0.001). Conclusions The performance of the new Chlamydia Rapid Test with first void male urine samples indicates that it would be an effective diagnostic tool for chlamydial infection in men. The availability of test results within an hour allows for immediate treatment and contact tracing, potentially reducing the risks of persistent infection and onward transmission. The test could also provide a simple and reliable alternative to nucleic acid amplification assays for testing of male urine in chlamydial screening programmes in high prevalence settings.

Comparison of the rate and size of HIV-1 viral load blips with Roche COBAS TaqMan HIV-1 versions 1.0 and 2.0 and implications for patient management

BACKGROUND The Roche COBAS TaqMan HIV-1 version 1.0 (v1.0) real-time PCR test detects more low level viral loads (VL) compared to the previous Roche Amplicor version 1.5 assay. Due to under-quantification issues, the Roche TaqMan HIV-1 version 2.0 (v2.0) was introduced in 2009. Controversy remains on differences at the low VL end, where clinical decisions regarding possible viral escape are based. OBJECTIVES To compare the rate and size of VL blips with v1.0 and v2.0 in virologically suppressed patients and describe the impact of v2.0 on patient management. STUDY DESIGN A cohort study of HIV-positive patients on antiretroviral therapy with a VL <50 copies/ml at the beginning and end of the study period (July 2008-February 2010). VL blips were compared during two consecutive 9-month periods, initially measured by v1.0, then v2.0. Genotypic resistance testing and treatment switches were described. RESULTS 1037 of 2584 patients (73.1% male) with median age 43 years were included. 2465 VL samples were measured on v1.0 and 2206 on v2.0. 108 (10.4%) patients had blips on v1.0 (4.4% of samples) compared to 99 (9.5%) patients (4.5% of samples) on v2.0. Median log VL was 1.89 (78 copies/ml) for v1.0 and 2.06 (116 copies/ml) for v2.0 (p=0.002). Further characterisation of 11 samples detected no resistance and no treatment modifications were identified. CONCLUSIONS TaqMan v1.0 and v2.0 have similar blip rates, while blips are higher with v2.0. This study supports the strategy to increase the threshold of concern for VL blips on v2.0.

Enterovirus infection of neuronal cells post-Rituximab

Here, we present the case of a 53-year-old man with stage IV B (Ann Arbour) T cell rich diffuse large B-cell Lymphoma (DLBCL), International Prognostic Index score 2, treated with standard chemotherapy CHOP-R (Cyclophosphamide, Hydroxydaunorubicin, Oncovin, Prednisolone, Rituximab) and intrathecal (i.t.) methotrexate. After the fourth cycle, repeat staging showed good response to treatment. Prior to his fifth cycle, he reported being pyrexial. However, throughout the observation period he remained apyrexial and was not neutropenic. Five days later he received his fifth cycle of chemotherapy, with methotrexate (i.t.) on day 7. Cerebrospinal fluid (CSF) examination showed 55 White Blood Cells (WBC) per microlitre, 90% lymphocytes with a reactive phenotype. At the sixth cycle of chemotherapy he complained of fever, mild slurring of speech, incoordination and unsteadiness, difficulty concentrating and recent weight loss. Chemotherapy was delayed. One week later the patient felt better but was neutropenic. Intravenous chemotherapy was delayed but methotrexate (i.t.) was given 5 d later. Following the procedure he had pyrexia of 38Æ8 C. The CSF showed 40 WBC/ll, 90% lymphocytes, protein (0Æ98 g/ml) and normal glucose. Examination revealed dysarthria, cerebellar signs and bilateral extensor plantar responses. CSF microscopy showed large lymphocytes with prominent nucleoli. Computed tomography and magnetic resonance imaging (MRI) brain scans were normal. He received Cytarabine (i.t.) and dexamethasone (i.v.). CSF was, on cytospin and immunophenotyping, compatible with a reactive process. Seven days later the patient deteriorated with a drop in Glasgow Coma Scale. Brain MRI showed enhancement of the left posterior aspect of the temporal lobe and an electroencephalogram supported an encephalopathy. Lumbar puncture showed: 103 WBC/ll, 65% lymphocytes, cryptococcal antigen negative, no organisms seen. Adenovirus, cytomegalovirus, Epstein-Barr virus, enterovirus, Human Herpes virus (HHV) 6, HHV7, John Cunningham (JC) virus were not detected. Mycobacterium tuberculosis, Listeria and Cryptococcus were also excluded. CSF immunophenotyping revealed T cell (CD3) predominance and <1% B cells (CD19). Biochemistry showed reduced total protein (54 g/l), with hypogammaglobulinemia (IgG < 1Æ5 g/l, IgA 0Æ23 g/l, IgM 0Æ07 g/l). At 1 month post-presentation, three CSF samples taken 2 d apart were Polymerase Chain Reaction (PCR) positive for enterovirus. The patient remained unconscious. A brain biopsy revealed widespread microglial activation, lymphocytic cuffing and gliosis, consistent with a subacute encephalitic process affecting both the white and grey matter, with associated mild lymphocytic leptomeningeal infiltration. The biopsy was also positive for enteroviral RNA by PCR. RT in situ PCR of the biopsy sections showed direct evidence of enteroviral infection of the neuronal cells (Fig 1). Despite treatment with intravenous immunoglobulins (2g/kg/month) the patient died 3 months after admission. CHOP-R is now standard treatment for DLBCL. Rituximab is increasingly employed in other areas of medicine and haematology. However, the resulting hypogammaglobulinaemia renders patients susceptible to severe and unusual forms of viral infections (Quartier et al, 2003; Sirvent-von Bueltzingsloewen et al, 2003; Steurer et al, 2003; Padate & Keidan, 2006). The link between B cell deficiencies and enteroviral meningoencephalitis was first recognised in the 1980’s, in Bruton’s X-linked agammaglobulinemia. Some of these patients were successfully treated with immunoglobulin replacement therapy. This case demonstrates the difficulty in diagnosing enteroviral meningoencephalitis due to non-specific symptoms and the low index of suspicion. It is thought that, in enteroviral infection, the virus is always detected in the gastrointestinal (GI) tract. However, in chronic encephalitis, by the time the disease is presented, the virus has seeded the central nervous system (CNS) and may have cleared from the GI tract and be undetectable in the stool. It may be also difficult to detect viral RNA in the CSF early after presentation because of low viral concentration. Although enteroviruses are not known to establish latency, there is evidence for their persistence over a period of years (Feuer et al, 2003, 2004). Animal cell studies suggest that enterovirus replication is only supported in dividing cells and is arrested in quiescent cells (Feuer et al, 2004). Neonatal susceptibility to enteroviral infection has been attributed to the immaturity of the immune system at that stage of life. However, studies of murine newborn have shown a dramatic drop in susceptibility at 10 d of age and confinement of infection mainly to neuronal progenitor cells. The immune system does not dramatically change at 10 d of age but neuronal progenitor cells differentiate and migrate to other areas of the brain (Feuer et al, 2003, 2005). Enteroviral genetic material remains in infected cells for years (Galbraith et al, 1997; Dunn et al, 2000). Therefore, it is plausible that enteroviral RNA may reactivate following an unidentified stimulus. In the presence of hypogammaglobulinaemia, reactivating enterovirus is not neutralised and can spread unchecked. In tissue culture, contact inhibition of cell cycle correspondence

Nosocomial transmission of parainfluenza 3 virus in hematological patients characterized by molecular epidemiology

A.V. Lee, D.F. Bibby, H. Oakervee, A. Rohatiner, I. Ushiro‐Lumb, D.A. Clark, F.M. Mattes. Nosocomial transmission of parainfluenza 3 virus in hematological patients characterized by molecular epidemiology.
Transpl Infect Dis 2011: 13: 433–437. All rights reserved

Improving hepatitis C services across the UK: response to a walk-in HCV testing service

The Department of Health (DH) estimates that approximately 0.4% of the UK population are chronically infected with hepatitis C virus (HCV) (that is, 200 000 people). As few as 10% of these individuals, who are at risk of end stage liver disease, are thought to be aware of their infection. Clearly action is required to identify and treat these patients with current drugs (pegylated interferons …