Jen Kok

Comparison of a Rapid Antigen Test with Nucleic Acid Testing during Cocirculation of Pandemic Influenza A/H1N1 2009 and Seasonal Influenza A/H3N2

ABSTRACT The rapid diagnosis of influenza is critical in optimizing clinical management. Rapid antigen tests have decreased sensitivity in detecting pandemic influenza A/H1N1 2009 virus compared to seasonal influenza A subtypes (53.4% versus 74.2%, P < 0.001). Nucleic acid tests should be used to detect pandemic influenza virus when rapid antigen tests are negative.

The impact of bacterial and viral co-infection in severe influenza

Please cite this paper as: Blyth et al. (2013) The impact of bacterial and viral co‐infection in severe influenza. Influenza and Other Respiratory Viruses 7(2) 168–176.

Tests for Latent Tuberculosis in People With ESRD: A Systematic Review.

BACKGROUND The relative diagnostic accuracy of interferon γ release assays (IGRAs; based on ELISA [enzyme-linked immunosorbent assay] or ELISPOT [enzyme-linked immunosorbent spot], ie, the QuantiFERON and T-SPOT.TB tests, respectively) and the tuberculin skin test (TST) for latent tuberculosis (TB) infection in people with end-stage kidney disease is uncertain and national guidelines for their use are inconsistent. STUDY DESIGN Systematic review. SELECTION CRITERIA FOR STUDIES Evaluated performance of tests for latent TB with clinical risk-factor assessment. SETTING & POPULATION People with end-stage kidney disease (chronic kidney disease stage 5 [eGFR <15] or kidney transplant recipients). No limits on setting. INDEX TESTS ELISA- or ELISPOT-based IGRAs, TST, assays to detect antimycobacterial antibodies, and flow cytometry-based tests. OUTCOMES Odds of test positivity with clinical risk factor for latent TB, expressed as ORs and relative ORs (RORs). RESULTS 47 studies (6,828 participants) were included, but only 30 studies (4,546 participants) contained sufficient data to contribute to meta-analysis. Studies were predominately in the dialysis population (23/30; 3,700 participants) in countries with low to moderate TB prevalence (0.0-50.0 cases/10(5) persons). BCG vaccination rate was variable (2.7%-100.0%). 9 studies compared IGRAs with the TST directly, 17 studies evaluated the TST only, and the other 4 studies evaluated other tests. Compared to a positive TST result, a positive ELISA-based IGRA result was associated more strongly with radiologic evidence of past TB (ROR, 4.29; 95% CI, 1.83-10.3; P = 0.001) and contact with active TB (ROR, 3.36; 95% CI, 1.61-7.01; P = 0.001). Compared to a negative TST result, a negative ELISA-based IGRA result was associated more strongly with BCG vaccination (ROR, 0.30; 95% CI, 0.14-0.63; P = 0.002). There were insufficient data to compare performance of the ELISPOT-based IGRA with the TST or ELISA-based IGRA. LIMITATIONS 17 of 47 included studies (36.2%) did not contain sufficient data to contribute to meta-analysis. CONCLUSIONS Compared to the TST, the ELISA-based IGRA was associated more strongly with risk factors for latent TB in end-stage kidney disease.

Detection of influenza A and B with the Alere™ i Influenza A & B: a novel isothermal nucleic acid amplification assay

Rapid influenza diagnostic tests (RIDTs) have an important role in clinical decision‐making; however, the performances of currently available assays vary widely.

Viral respiratory infections among Hajj pilgrims in 2013

Middle East respiratory syndrome coronavirus (MERS-CoV) has emerged in the Arabian Gulf region, with its epicentre in Saudi Arabia, the host of the ‘Hajj’ which is the world’s the largest mass gathering. Transmission of MERS-CoV at such an event could lead to its rapid worldwide dissemination. Therefore, we studied the frequency of viruses causing influenza-like illnesses (ILI) among participants in a randomised controlled trial at the Hajj 2013. We recruited 1038 pilgrims from Saudi Arabia, Australia and Qatar during the first day of Hajj and followed them closely for four days. A nasal swab was collected from each pilgrim who developed ILI. Respiratory viruses were detected using multiplex RT-PCR. ILI occurred in 112/1038 (11%) pilgrims. Their mean age was 35 years, 49 (44%) were male and 35 (31%) had received the influenza vaccine pre-Hajj. Forty two (38%) pilgrims had laboratory-confirmed viral infections; 28 (25%) rhinovirus, 5 (4%) influenza A, 2 (2%) adenovirus, 2 (2%) human coronavirus OC43/229E, 2 (2%) parainfluenza virus 3, 1 (1%) parainfluenza virus 1, and 2 (2%) dual infections. No MERS-CoV was detected in any sample. Rhinovirus was the commonest cause of ILI among Hajj pilgrims in 2013. Infection control and appropriate vaccination are necessary to prevent transmission of respiratory viruses at Hajj and other mass gatherings.

Current status of matrix-assisted laser desorption ionisation-time of flight mass spectrometry in the clinical microbiology laboratory

Summary The integration of matrix-assisted laser desorption ionisation-time of flight mass spectrometry (MALDI-TOF MS) into many clinical microbiology laboratories has revolutionised routine pathogen identification. MALDI-TOF MS complements and has good potential to replace existing phenotypic identification methods. Results are available in a more clinically relevant timeframe, particularly in bacteraemic septic shock. Novel applications include strain typing and the detection of antimicrobial resistance, but these are not widely used. This review discusses the technical aspects, current applications, and limitations of MALDI-TOF MS.

Molecular diagnosis of respiratory viruses

Summary The increasing availability of nucleic acid amplification tests since the 1980s has revolutionised our understanding of the pathogenesis, epidemiology, clinical and laboratory aspects of known and novel viral respiratory pathogens. High-throughput, multiplex polymerase chain reaction is the most commonly used qualitative detection method, but utilisation of newer techniques such as next-generation sequencing will become more common following significant cost reductions. Rapid and readily accessible isothermal amplification platforms have also allowed molecular diagnostics to be used in a ‘point-of-care’ format. This review focuses on the current applications and limitations of molecular diagnosis for respiratory viruses.

Pandemic (H1N1) 2009 influenza virus seroconversion rates in HIV-infected individuals.

The impact of pandemic (H1N1) 2009 influenza in HIV-infected individuals is unknown. Determining the prevalence of pandemic influenza in this at-risk group will guide vaccination programs. After the first pandemic wave, the seroprevalence rate of pandemic influenza in HIV-infected individuals in western Sydney, New South Wales, Australia, was 34.2%, similar to the rate observed in the general population. However, true seroprevalence is more accurately determined by seroconversion, defined as a 4-fold or greater rise between preexposure and postexposure antibody levels, which was 14.6% in the present study. Seroconversion rates were independent of CD4+ T-lymphocyte count and HIV plasma load. Neither HIV infection, nor severe immunosuppression, was a significant risk factor for pandemic influenza during the first southern hemisphere pandemic wave.

First reported outbreak of locally acquired hepatitis E virus infection in Australia

Objective: To determine the source and extent of a locally acquired hepatitis E virus (HEV) infection outbreak.

Viral Pneumonitis Is Increased in Obese Patients during the First Wave of Pandemic A(H1N1) 2009 Virus

Introduction There is conflicting data as to whether obesity is an independent risk factor for mortality in severe pandemic (H1N1) 2009 influenza (A(H1N1)pdm09). It is postulated that excess inflammation and cytokine production in obese patients following severe influenza infection leads to viral pneumonitis and/or acute respiratory distress syndrome. Methods Demographic, laboratory and clinical data prospectively collected from obese and non-obese patients admitted to nine adult Australian intensive care units (ICU) during the first A(H1N1)pdm09 wave, supplemented with retrospectively collected data, were compared. Results Of 173 patients, 100 (57.8%), 73 (42.2%) and 23 (13.3%) had body mass index (BMI) <30 kg/m2, ≥30 kg/m2 (obese) and ≥40 kg/m2 (morbidly obese) respectively. Compared to non-obese patients, obese patients were younger (mean age 43.4 vs. 48.4 years, p = 0.035) and more likely to develop pneumonitis (61% vs. 44%, p = 0.029). Extracorporeal membrane oxygenation use was greater in morbidly obese compared to non-obese patients (17.4% vs. 4.7%, p = 0.04). Higher mortality rates were observed in non-obese compared to obese patients, but not after adjusting for severity of disease. C-reactive protein (CRP) levels and hospital length of stay (LOS) were similar. Amongst ICU survivors, obese patients had longer ICU LOS (median 11.9 vs. 6.8 days, p = 0.017). Similar trends were observed when only patients infected with A(H1N1)pdm09 were examined. Conclusions Among patients admitted to ICU during the first wave of A(H1N1)pdm09, obese and morbidly obese patients with severe infection were more likely to develop pneumonitis compared to non-obese patients, but mortality rates were not increased. CRP is not an accurate marker of pneumonitis.