Evaluation of hepatitis C virus RNA stability in room temperature and multiple freeze–thaw cycles by COBAS AmpliPrep/COBAS TaqMan HCV

Transplantation Outcomes in Hepatitis C Virus-Positive Donor Hearts After Circulatory Death

Although the use of hepatitis C virus (HCV)-positive hearts has been shown to be safe and effective among donors with donation after brain death (DBD), it remains unknown whether such organs recovered after circulatory death (DCD) have similar outcomes. In contradistinction to recovery from DBD using cold static organ storage, DCD procurement processes typically use normothermic-perfusion transport strategies that necessitate the use of a large volume of donor blood and involve exposure to temperatures oscillating between cold to dominantly normothermic conditions. We performed a retrospective analysis of United Network for Organ Sharing (UNOS) registry data in the United States and found that clinical outcomes do not differ with respect to rates of treated allograft rejection, early and 1-year survival. Ideally, the organ-recovery source should not result in a bias in organ-offer acceptance from HCV-positive donors, although long-term outcome data are yet unavailable.

Effect of extrinsic factors on the detection of PRRSV and a porcine-specific internal sample control in serum, oral fluid, and fecal specimens tested by RT-rtPCR

We characterized the effect of 1) temperature × time, 2) freeze-thaw cycles, and 3) high porcine reproductive and respiratory syndrome virus (PRRSV) RNA concentrations on the detection of PRRSV and a porcine-specific internal sample control (ISC) in serum, oral fluid, and fecal samples using a commercial PRRSV RT-rtPCR assay (Idexx). In study 1, the effect of temperature × time on PRRSV and ISC detection was shown to be specimen dependent. In serum stored at 4, 10, or 20°C, PRRSV detection was consistent for up to 168 h, but storage at 30°C reduced detectable PRRSV RNA. ISC RNA was stable in serum held at 4 and 10°C, but not at 20 and 30°C. In contrast, PRRSV and ISC RNAs in oral fluid and fecal samples continuously decreased at all temperature × time treatments. Based on these data, serum samples should be stored at ≤ 20°C to optimize PRRSV RNA detection. Oral fluid and fecal samples should be frozen in a non-self-defrosting freezer until tested. In study 2, freeze-thaw cycles had little impact on PRRSV and ISC detection, but more so in oral fluids than serum or fecal samples. Thus, freeze-thaw cycles in oral fluids should be minimized before RT-rtPCR testing. In study 3, the ISC was not affected by high concentrations of PRRSV RNA in serum, oral fluid, or fecal samples. It should not be assumed that data from our PRRSV study are applicable to other pathogens; additional pathogen-specific studies are required.

Taking a step back from testing: Preanalytical considerations in molecular infectious disease diagnostics

Recent studies evaluating the preanalytical factors that impact the outcome of nucleic-acid based methods for the confirmation of SARS-CoV-2 have illuminated the importance of identifying variables that promoted accurate testing, while using scarce resources efficiently. The majority of laboratory errors occur in the preanalytical phase. While there are many resources identifying and describing mechanisms for main laboratory testing on automated platforms, there are fewer comprehensive resources for understanding important preanalytical and environmental factors that affect accurate molecular diagnostic testing of infectious diseases. This review identifies evidence-based factors that have been documented to impact the outcome of nucleic acid-based molecular techniques for the diagnosis of infectious diseases.

Pre-analytical Practices in the Molecular Diagnostic Tests, A Concise Review

Molecular assays for detection of nucleic acids in biologic specimens are valuable diagnostic tools supporting clinical diagnoses and therapeutic decisions. Pre-analytical errors, which occur before or during processing of nucleic acid extraction, contribute a significant role in common errors that take place in molecular laboratories. Certain practices in specimen collection, transportation, and storage can affect the integrity of nucleic acids before analysis. Applying best practices in these steps, helps to minimize those errors and leads to better decisions in patient diagnosis and treatment. Widely acceptable recommendations, which are for optimal molecular assays associated with pre-analytic variables, are limited. In this article, we have reviewed most of the important issues in sample handling from bed to bench before starting molecular tests, which can be used in diagnostic as well as research laboratories. We have addressed the most important pre-analytical points in performing molecular analysis in fixed and unfixed solid tissues, whole blood, serum, plasma, as well as most of the body fluids including urine, fecal and bronchial samples, as well as prenatal diagnosis samples.

Evaluation of the role of respiratory syncytial virus surface glycoproteins F and G on viral stability and replication: implications for future vaccine design

Respiratory syncytial virus (RSV) remains a leading cause of infant mortality worldwide and exhaustive international efforts are underway to develop a vaccine. However, vaccine development has been hindered by a legacy of vaccine-enhanced disease, poor viral immunogenicity in infants, and genetic and physical instabilities. Natural infection with RSV does not prime for enhanced disease encouraging development of live-attenuated RSV vaccines for infants; however, physical instabilities of RSV may limit vaccine development. The role of RSV strain-specific differences on viral physical stability remains unclear. We have previously demonstrated that the RSV fusion (F) surface glycoprotein is responsible for mediating significant differences in thermostability between strains A2 and A2-line19F. In this study, we performed a more comprehensive analysis to characterize the replication and physical stability of recombinant RSV A and B strains that differed only in viral attachment (G) and/or F surface glycoprotein expression. We observed significant differences in thermal stability, syncytia size, pre-fusion F incorporation and viral growth kinetics in vitro, but limited variations to pH and freeze-thaw inactivation among several tested strains. Consistent with earlier studies, A2-line19F showed significantly enhanced thermal stability over A2, but also restricted growth kinetics in both HEp2 and Vero cells. As expected, no significant differences in susceptibility to UV inactivation were observed. These studies provide the first analysis of the physical stability of multiple strains of RSV, establish a key virus strain associated with enhanced thermal stability compared to conventional lab strain A2, and further support the pivotal role RSV F plays in virus stability.

Field evaluation of GeneXpert® (Cepheid) HCV performance for RNA quantification in a genotype 1 and 6 predominant patient population in Cambodia

GeneXpert^® (Cepheid) is the only WHO prequalified platform for hepatitis C virus (HCV) nucleic acid amplification testing that is suitable for point-of-care use in resource-limited contexts. However, its application is constrained by the lack of evidence on genotype 6 (GT6) HCV. We evaluated its field performance among a patient population in Cambodia predominantly infected with GT6. Between August and September 2017, we tested plasma samples obtained from consenting patients at Médecins Sans Frontières' HCV clinic at Preah Kossamak Hospital for HCV viral load (VL) using GeneXpert^® and compared its results to those obtained using COBAS^® AmpliPrep/Cobas^® TaqMan^® HCV Quantitative Test, v2.0 (Roche) at the Institut Pasteur du Cambodge. Among 769 patients, 77% of the seropositive patients (n = 454/590) had detectable and quantifiable VL using Roche and 43% (n = 195/454) were GT6. The sensitivity and specificity of GeneXpert^® against Roche were 100% (95% CI 99.2, 100.0) and 98.5% (95% CI 94.8, 99.8). The mean VL difference was -0.01 (95% CI -0.05, 0.02) log₁₀  IU/mL for 454 samples quantifiable on Roche and -0.07 (95% CI -0.12, -0.02) log₁₀  IU/mL for GT6 (n = 195). The limit of agreement (LOA) was -0.76 to 0.73 log₁₀  IU/mL for all GTs and -0.76 to 0.62 log₁₀ IU/mL for GT6. Twenty-nine GeneXpert^® results were outside the LOA. Frequency of error and the median turnaround time (TAT) for GeneXpert^® were 1% and 0 days (4 days using Roche). We demonstrated that the GeneXpert^® HCV assay has good sensitivity, specificity, quantitative agreement, and TAT in a real-world, resource-limited clinical setting among GT6 HCV patients.

Nosocomial transmission of hepatitis C virus in a liver transplant center in Hong Kong: implication of reusable blood collection tube holder as the vehicle for transmission

BACKGROUND

A liver transplant recipient developed hospital-acquired symptomatic hepatitis C virus (HCV) genotype 6a infection 14 months post transplant.

OBJECTIVE

Standard outbreak investigation.

METHODS

Patient chart review, interviews of patients and staff, observational study of patient care practices, environmental surveillance, blood collection simulation experiments, and phylogenetic study of HCV strains using partial envelope gene sequences (E1-E2) of HCV genotype 6a strains from the suspected source patient, the environment, and the index patient were performed.

RESULTS

Investigations and data review revealed no further cases of HCV genotype 6a infection in the transplant unit. However, a suspected source with a high HCV load was identified. HCV genotype 6a was found in a contaminated reusable blood-collection tube holder with barely visible blood and was identified as the only shared item posing risk of transmission to the index case patient. Also, 14 episodes of sequential blood collection from the source patient and the index case patient were noted on the computerized time log of the laboratory barcoding system during their 13 days of cohospitalization in the liver transplant ward. Disinfection of the tube holders was not performed after use between patients. Blood collection simulation experiments showed that HCV and technetium isotope contaminating the tip of the sleeve capping the sleeved-needle can reflux back from the vacuum-specimen tube side to the patient side.

CONCLUSIONS

A reusable blood-collection tube holder without disinfection between patients can cause a nosocomial HCV infection. Single-use disposable tube holders should be used according to the recommendations by Occupational Safety and Health Administration and World Health Organization.

Ebola Preparedness: Diagnosis Improvement Using Rapid Approaches for Proficiency Testing

The unprecedented 2015 Ebolavirus (EBOV) outbreak in West Africa was declared a public health emergency, making diagnosis and quality of testing a global issue. The accuracy of laboratory diagnostic capacity for EBOV was assessed in 2014 to 2016 using a proficiency testing (PT) strategy developed by the Royal College of Pathologists of Australasia Quality Assurance Programs (RCPAQAP) in Biosecurity. Following a literature search, EBOV-specific gene targets were ranked according to the frequency of their use in published methods. The most commonly used gene regions (nucleoprotein [NP], glycoprotein [GP], and RNA-dependent RNA polymerase [L]) were selected for the design of in vitro RNA transcripts to be included in the simulated EBOV specimens used for EBOV detection with PCR-based assays. Specimens were tested for stability and found to be stable on long-term storage (1 year) at -80°C and on shorter-term storage in lyophilized form (1 week at ambient temperature and a subsequent week at -80°C). These specimens were used in three EBOV PTs offered from April 2014 to March 2016. In the first and third PTs, all laboratories (3/3 and 9/9, respectively) correctly identified specimens containing EBOV RNA transcripts, while in the second PT, all but one laboratory (5/6) correctly confirmed the presence of EBOV. The EBOV PT panel was useful for ensuring the competency of laboratories in detecting EBOV in the absence of readily available clinical samples. The simulated EBOV specimen was safe, stable, and reliable and can be used in lyophilized form for future EBOV PT programs, allowing simplicity of transport.

Knowledge and prevalence of viral hepatitis among beauticians

Beauty treatments, such as tattooing, piercing, manicures, pedicures, and barbershop shaving, can pose an important risk of virus transmission. This study was conducted to determine hepatitis A virus (HAV), hepatitis B virus (HBV), and hepatitis C virus (HCV) prevalence in a sample of beauticians from Rio de Janeiro (Southeast Brazil) and to assess the knowledge and attitudes of these professionals regarding viral hepatitis and their practices during their activities. One hundred nineteen beauticians were recruited in September 2010. Serum samples were tested for total anti-HAV, total anti-HBc, HBsAg, anti-HBs, and anti-HCV reactivity. A questionnaire was administered to identify socio-demographic risk factors and to determine knowledge and attitudes regarding viral hepatitis. Prevalence was 73.9% for total anti-HAV, 0% for HBsAg, 5.9% for anti-HBc, 23.6% for anti-HBs, and 0.8% for anti-HCV. Most professionals (81.5%) were well informed (4-7 correct answers) and reported the use of disposable sandpaper and nail sticks and sterilized pliers, but only 40% of them reported adequate processes of disinfection/sterilization. In conclusion, a high prevalence of HAV infection and a low prevalence of HBV and HCV infection were observed among beauticians. In addition, most of these individuals were not immune to HBV, indicating the need for vaccination campaigns targeting these professionals. Most of these professionals were well informed regarding viral hepatitis, although there was a gap in knowledge regarding disinfection and sterilization procedures. Public health prevention strategies should be adopted to improve education about disinfection/sterilization procedures for manicures and pedicures.