Evaluation of disinfectant efficacy against hepatitis C virus using a RT-PCR-based method

First identification of bovine hepacivirus in wild boars

Hepatitis C virus (HCV) is a major cause of chronic hepatitis, cirrhosis and hepatocellular carcinoma in humans. Humans were long considered the only hosts of Hepacivirus. Recently HCV-like sequences have been found in several animal species. Hepaciviruses are considered species-specific but a wider host range and a zoonotic role has been hypothesized. We report the first detection of bovine hepacivirus (BovHepV) sequences in wild boars. A total of 310 wild boars hunted in Campania region were investigated with a pan-hepacivirus nested-PCR protocol for the NS3 gene. Hepacivirus RNA was detected in 5.8% of the animals. Sequence and phylogenetic analysis showed high homology with BovHepV subtype F, with nucleotide identity of 99%. The positive wild boars were georeferenced, revealing high density of livestock farms, with no clear distinction between animal husbandry and hunting areas. These findings might suggest the ability of BovHepV to cross the host-species barrier and infect wild boars.

Evaluation of a novel commercial quaternary ammonium compound for eradication of Mycobacteria, HCV and HBV in Egypt

Endoscopes are a common source of outbreaks of healthcare-associated infections. It is therefore important to identify high-level disinfectants capable of eliminating or killing all vegetative bacteria, mycobacteria, and viruses. Aldehydebased disinfectants are most commonly used in clinical practice but resistance has recently been detected and side effects associated with these disinfectants are well documented. In this study, we evaluated Virusolve+® EDS, a novel quaternary ammonium compound formulation supplied by Amity international, against Mycobacterium bovis (ATCC-27289), hepatitis C virus (HCV)-positive serum and hepatitis B surface antigen-positive serum. We also compared its efficacy against Cidex® (glutaraldehyde 2%), an aldehyde-based disinfectant. M. bovis showed no growth after 10 weeks with either Virusolve+® or Cidex®. Virusolve+® achieved a 10(4)- fold reduction in the initial 10(6) HCV load under clean conditions (without red blood cells) for 20 min, whereas Cidex® achieved this reduction under clean and dirty conditions (without and with red blood cells, respectively) after both 10 and 20 min. Both Virusolve+® and Cidex® were able to eradicate hepatitis B virus (HBV) infectivity under clean conditions after 10 and 20 min, whereas under dirty conditions they were only able to eradicate virus infectivity after 20 min. Virusolve+® EDS when compared with Cidex® showed equal mycobactericidal activity completely eradicating M. bovis. However, both showed comparable virucidal activity against HBV, which was more effective under clean conditions, emphasizing the importance of the cleaning step in endoscope reprocessing. Cidex® was more effective at eradicating HCV under dirty conditions after a short contact time.

Effects of disinfection on the molecular detection of porcine epidemic diarrhea virus

Routine detection of porcine epidemic diarrhea virus (PEDV) is currently limited to RT-PCR but this test cannot distinguish between viable and inactivated virus. We evaluated the capability of disinfectants to both inactivate PEDV and sufficiently damage viral RNA beyond RT-PCR detection. Five classes of disinfectants (phenol, quaternary ammonium compound, sodium hypochlorite, oxidizing agent, and quaternary ammonium/glutaraldehyde combination) were evaluated in vitro at varying concentrations, both in the presence and absence of swine feces, and at three different temperatures. No infectious PEDV was recovered after treatment with evaluated disinfectants. Additionally, all tested disinfectants except for 0.17% sodium hypochlorite dramatically reduced qRT-PCR values. However, no disinfectants eliminated RT-PCR detection of PEDV across all replicates; although, 0.52%, 1.03% and 2.06% solutions of sodium hypochlorite and 0.5% oxidizing agent did intermittently produce RT-PCR negatives. To simulate field conditions in a second aim, PEDV was applied to pitted aluminum coupons, which were then treated with either 2.06% sodium hypochlorite or 0.5% oxidizing agent. Post-treatment surface swabs of the coupons tested RT-PCR positive but were not infectious to cultured cells or naïve pigs. Ultimately, viable PEDV was not detected following application of each of the tested disinfectants, however in most cases RT-PCR detection of viral RNA remained. RT-PCR detection of PEDV is likely even after disinfection with many commercially available disinfectants.

Qualitative accounts of needle and syringe cleaning techniques among people who inject drugs in Sydney, Australia

INTRODUCTION AND AIMS

Cleaning needles/syringes is an important second-line harm reduction strategy, yet there is limited information on practices employed by people who inject drugs in Australia. This study attempts to identify and assess cleaning practices in terms of the techniques involved and the social contexts in which cleaning takes place.

DESIGN AND METHODS

As part of an exploratory qualitative study in south-west Sydney, in-depth interviews and simulated cleaning exercises were conducted with 12 people who inject drugs. Interviews were digitally recorded and transcribed verbatim. Open coding was used to inductively classify data into themes, and data were examined for patterns and variations in the relationships within and between themes.

RESULTS

Data indicate that cleaning and reuse of needles/syringes was common in this small sample. The most frequently utilised reagent was cool water. While all participants reported cleaning and reusing only their own equipment, none of the techniques demonstrated would have been sufficient to deactivate human immunodeficiency virus or hepatitis C virus.

DISCUSSION AND CONCLUSIONS

Results suggest that even where cleaning of needles and syringes is widespread, people who inject drugs may not engage in efficacious cleaning. The combination of the complexity of current cleaning messages and a lack of accurate information about efficacious techniques are likely to contribute to poor cleaning practice. Australia could benefit from the development of a nationally consistent cleaning message; however, the evidence would suggest that this would need to be accompanied by strategies designed to simplify and disseminate this information in order to increase the uptake of efficacious cleaning methods by people who inject drugs.

Hexon denaturation of human adenoviruses by different groups of biocides

Human adenoviruses have often been used as surrogates for testing broad-spectrum virucidal efficacy of biocides. However, recent studies have shown that members of this group of viruses have quite different chemical sensitivities and only serotypes 5 and 44 can be recommended as model viruses. In this study, the hexon protein of the serotypes 1, 2, 5, 6 and 8 was exposed to biocides and subsequently detected by western blotting and the RPS Adeno Detector. Only peracetic acid (PAA) at a relatively high concentration of 0.5% led to complete denaturation of hexon protein within 60 min. This effect was uniform for all adenoviruses tested and was not observed after exposure to 0.05-2.5% povidone-iodine (PVP-I) or 0.7% formaldehyde. However, viral infectivity and genome integrity were influenced by PVP-I and formaldehyde and lower concentrations of PAA. In conclusion, the hexon protein of human adenoviruses shows an unexpectedly high and uniform resistance to chemical biocides. The different chemical sensitivities of adenoviruses cannot be explained by the sensitivity of this main structural compound, but the present findings provide new insights into the virucidal action of disinfectants.

Inactivation of human adenovirus genome by different groups of disinfectants

Human adenoviruses are model viruses for testing the virucidal efficacy of disinfectants. However, a recent study has shown that the chemical sensitivity of adenovirus serotypes varies significantly, possibly due to the composition of the viral capsid and/or the resistance of nucleic acids. We have investigated the effect of molecular changes in the viral genome of the human adenovirus subgenera C and D. A common oligonucleotide fragment within the hexon gene was amplified by polymerase chain reaction (PCR) after exposure to liposomal povidone-iodine (PVP-I), peracetic acid (PAA), and formaldehyde. The findings were compared with infectivity in cell cultures. PVP-I (0.125%) destroyed the infectivity of most serotypes within 60 min. However, PCR revealed no destruction of the adenoviral genome in most serotypes, even after exposure to higher PVP-I concentrations. PAA (0.5%) failed to inactivate the hexon gene of adenovirus types 22 and 44. Furthermore, the hexon gene of adenovirus type 22 was not altered by 0.7% formaldehyde. In conclusion, the genomes of human adenoviruses show considerably more chemical resistance than the complete viral particle. The molecular resistance of individual serotypes also varies. However, there was no clear correlation between the differences in the effect of disinfectants on infectivity of the complete viral particle and destruction of the viral genome.

Blood-borne viruses and their survival in the environment: is public concern about community needlestick exposures justified?

BACKGROUND

More than 30 million needle syringes are distributed per year in Australia as a component of harm-reduction strategies for injecting drug users (IDU). Discarded needle syringes create considerable anxiety within the community, but the extent of needlestick injuries and level of blood-borne virus transmission risk is unclear. We have undertaken a review of studies of blood-borne virus survival as the basis for advice and management of community needlestick injuries.

METHODS

A Medline review of published articles on blood-borne virus survival and outcome from community injuries.

RESULTS

Hepatitis B virus (HBV), hepatitis C virus (HCV) and human immunodeficiency virus (HIV) can all survive outside the human body for several weeks, with virus survival influenced by virus titer, volume of blood, ambient temperature, exposure to sunlight and humidity. HBV has the highest virus titers in untreated individuals and is viable for the most prolonged periods in needle syringes stored at room temperature. However, prevalence of HBV and HIV are only 1-2% within the Australian IDU population. In contrast, prevalence of HCV is 50-60% among Australian IDUs and virus survival in needle syringes has been documented for prolonged periods. There have been no published cases of blood-borne virus transmission following community needlestick injury in Australia.

CONCLUSION

The risk of blood-borne virus transmission from syringes discarded in community settings appears to be very low. Despite this, procedures to systematically follow up individuals following significant needlestick exposures sustained in the community setting should be developed.

Surrogate viruses for testing virucidal efficacy of chemical disinfectants

Since important agents of viral nosocomial infections like hepatitis B and C viruses and norovirus do not replicate sufficiently in cell culture systems, disinfectants with suspected efficacy against these viruses must be evaluated by different methods. Besides molecular approaches and indirect tests, the use of surrogate viruses with similar biophysical properties and genomic structure allows the assessment of virucidal efficacy of chemical disinfectants in quantitative suspension tests. Furthermore, insights into the survival of these viruses in the environment are possible. In recent years, duck hepatitis B virus and bovine viral diarrhoea virus have been tested as surrogates for hepatitis B and C viruses. Feline calicivirus serves as a surrogate for the group of norovirus. By including these viruses in inactivation experiments, valuable data from suspension tests can be derived on the virucidal efficacy of chemical disinfectants. Even in vivo tests using fingerpads of adult volunteers can be performed with these animal viruses without risk of infection. In contrast to in vitro examinations, the results of these tests allow use recommendations of chemical disinfectants for outbreak situations and daily routine disinfection.

The effect of various disinfectants on detection of avian influenza virus by real time RT-PCR

An avian influenza (AI) real time reverse transcriptase-polymerase chain reaction (RRT-PCR) test was previously shown to be a rapid and sensitive method to identify AI virus-infected birds in live-bird markets (LBMs). The test can also be used to identify avian influenza virus (AIV) from environmental samples. Consequently, the use of RRT-PCR was being considered as a component of the influenza eradication program in the LBMs to assure that each market was properly cleaned and disinfected before allowing the markets to be restocked. However, the RRT-PCR test cannot differentiate between live and inactivated virus, particularly in environmental samples where the RRT-PCR test potentially could amplify virus that had been inactivated by commonly used disinfectants, resulting in a false positive test result. To determine whether this is a valid concern, a study was conducted in three New Jersey LBMs that were previously shown to be positive for the H7N2 AIV. Environmental samples were collected from all three markets following thorough cleaning and disinfection with a phenolic disinfectant. Influenza virus RNA was detected in at least one environmental sample from two of the three markets when tested by RRT-PCR; however, all samples were negative by virus isolation using the standard egg inoculation procedure. As a result of these findings, laboratory experiments were designed to evaluate several commonly used disinfectants for their ability to inactivate influenza as well as disrupt the RNA so that it could not be detected by the RRT-PCR test. Five disinfectants were tested: phenolic disinfectants (Tek-trol and one-stroke environ), a quaternary ammonia compound (Lysol no-rinse sanitizer), a peroxygen compound (Virkon-S), and sodium hypochlorite (household bleach). All five disinfectants were effective at inactivating AIV at the recommended concentrations, but AIV RNA in samples inactivated with phenolic and quaternary ammonia compounds could still be detected by RRT-PCR. The peroxygen and chlorine compounds were effective at some concentrations for both inactivating virus and preventing amplification by RRT-PCR. Therefore, the RRT-PCR test can potentially be used to assure proper cleaning and disinfection when certain disinfectants are used.

Short- and long-term effects of handwashing with antimicrobial or plain soap in the community

Little is known about effects of public use of antimicrobial handwashing soap. A double-blinded, randomized clinical trial of hands of primary caretakers in 238 inner city households was conducted in which effects of plain or antimicrobial (containing 0.2% triclosan) handwashing soap on bacterial counts of the hands were compared before and after a single wash and before and after handwashing following a year of product use. The randomly assigned product was provided without cost to each household during monthly home visits, and compliance with product use was monitored. Households were contacted by telephone weekly and with a home visit monthly for 11 months. Hand cultures were obtained before and after handwashing at baseline and after 11 months, using a modified glove juice technique. Overall, there were no significant differences in pre-to-post handwashing counts at baseline (p = 0.41), but by the end of one year, post-wash counts were significantly lower than pre-wash (p = 0.000) for those using either antimicrobial or plain soap. There were no significant differences in mean log counts either before or after handwashing between those using the antimicrobial or plain soap at baseline or after a year of use (all p values > 0.28). For the group using antimicrobial soap, higher counts were observed post-handwashing in 31.3% of paired samples at baseline and 26.7% after one year (p = 0.03). A single handwash had minimal effect on quantity of hand flora, but there were significant effects over time, regardless of whether antimicrobial or plain soap was used. In the absence of more definitive evidence, the risk-benefit ratio argues in favor of targeted rather than ubiquitous, general household use of antimicrobial soap.