781. Antiviral Effectiveness of Different Disinfectants on Surfaces Contaminated with Surrogate Non-enveloped Viruses

Background Contamination of surfaces with virions remains an important medical issues because they can serve as fomites for viral transmission. Long acting disinfectants are important because viruses can remain viable for extended durations. Here we assessed the anti-viral efficacy of various environmental spray disinfectants against F specific coliphage MS2, and Feline Calicivirus (FCV) as surrogate non-enveloped viruses. Methods MS2 was grown and titrated according to Environmental Protection Agency method 1601 and counted as plague forming unit per milliliter (PFU/mL.). Strain F9 of FCV was propagated and titrated in monolayers of Crandell-Reese Feline Kidney cells. Commercially available and an experimental disinfectant based on a biguanide combination were tested. The disinfectants, both wet and as dried residues, were compared on silicone surfaces for reduction of viral loads following 1-minute exposure to high viral load challenges (106-107 PFU/ml). Sterilized deionized water was used as a control. Results Results (as log10 reduction relative to sterilized deionized water control) are tabulated below for the disinfectants in wet and dry states following 1-minute viral challenges. Log10 reductions of MS2 and FCV viral loads following 1-minute exposures to disinfectants in wet and dry residue states. Conclusion The disinfectants were generally much less effective as dried residues than wet. The biguanide-combination and hydrogen peroxide-combination disinfectants were the most effective disinfectants tested in both wet and dry residue states. Both warrant further study for extended eradication of highly infectious viruses on surfaces. Disclosures All Authors: No reported disclosures

Determination of Volatile Organic Compounds in Air by GC/MS: Italian Proficiency Tests

Three national proficiency scheme rounds on the analysis of volatile organic compounds (VOCs) in air have been organized; the first between April and June 2007, the second between May and July 2008, and the third between April and June 2010. A group of about 10 Italian laboratories used the U.S. Environmental Protection Agency Method TO-15 for the determination of VOCs in air collected in canisters. A canister containing a VOC mixture, prepared by dynamic dilution from certified reference materials, was shipped to each participating laboratory; VOC concentrations were between 2 and 50 parts per billion by volume. Homogeneity of the samples prepared was tested and considered adequate according to ISO 13528:2005(E); stability was also checked. The canisters were analyzed by the laboratories within 30 days by GC/MS. The data were analyzed by robust statistics. Good accordance among laboratory results was obtained.

Cryptosporidium Oocysts and Giardia Cysts on Salad Products Irrigated with Contaminated Water

A field study in Valencia, Spain, was done to determine the occurrence of Giardia and Cryptosporidium on salad products that are frequently eaten raw, such as lettuces and Chinese cabbage, and in irrigation waters. Four water samples were taken weekly 1 month before harvesting the vegetables. All water samples were analyzed using techniques included in the U.S. Environmental Protection Agency Method 1623. Standard methods for detecting protozoan parasites on salad vegetables are not available. Published techniques for the isolation of parasites from vegetables generally have low and variable recovery efficiencies. In this study, vegetables were analyzed using a recently reported method for detection of Cryptosporidium oocysts and Giardia cysts on salad products. The waters tested were positive for both Cryptosporidium and Giardia. Of 19 salad products studied, we observed Cryptosporidium in 12 samples and Giardia in 10 samples. Recoveries of the Texas Red–stained Cryptosporidium and Giardia, which were used as internal controls, were 24.5% ± 3.5% for Cryptosporidium and 16.7% ± 8.1% for Giardia (n = 8). This study provides data on the occurrence of Cryptosporidium and Giardia in salad products in Spain. The method was useful in the detection of Cryptosporidium oocysts and Giardia cysts on the vegetables tested, and it provides a useful analytical tool for occurrence monitoring.

Identification of Particle Size Classes Inhibiting Protozoan Recovery from Surface Water Samples via U.S. Environmental Protection Agency Method 1623

ABSTRACT Giardia species recovery by U.S. Environmental Protection Agency method 1623 appears significantly impacted by a wide size range (2 to 30 μm) of particles in water and organic matter. Cryptospori dium species recovery seems negatively correlated only with smaller (2 to 10 μm), presumably inorganic particles. Results suggest constituents and mechanisms interfering with method performance may differ by protozoan type.

Molecular Forensic Profiling of Cryptosporidium Species and Genotypes in Raw Water

ABSTRACT The emerging concept of host specificity of Cryptosporidium spp. was exploited to characterize sources of fecal contamination in a watershed. A method of molecular forensic profiling of Cryptosporidium oocysts on microscope slides prepared from raw water samples processed by U.S. Environmental Protection Agency Method 1623 was developed. The method was based on a repetitive nested PCR-restriction fragment length polymorphism-DNA sequencing approach that permitted the resolution of multiple species/genotypes of Cryptosporidium in a single water sample.

Effects of Seeding Procedures and Water Quality on Recovery of Cryptosporidium Oocysts from Stream Water by Using U.S. Environmental Protection Agency Method 1623

ABSTRACT U.S. Environmental Protection Agency method 1623 is widely used to monitor source waters and drinking water supplies for Cryptosporidium oocysts. Matrix spikes, used to determine the effect of the environmental matrix on the method's recovery efficiency for the target organism, require the collection and analysis of two environmental samples, one for analysis of endemic oocysts and the other for analysis of recovery efficiency. A new product, ColorSeed, enables the analyst to determine recovery efficiency by using modified seeded oocysts that can be differentiated from endemic organisms in a single sample. Twenty-nine stream water samples and one untreated effluent sample from a cattle feedlot were collected in triplicate to compare modified seeding procedures to conventional seeding procedures that use viable, unmodified oocysts. Significant negative correlations were found between the average oocyst recovery and turbidity or suspended sediment; this was especially apparent in samples with turbidities greater than 100 nephelometric turbidity units and suspended sediment concentrations greater than 100 mg/liter. Cryptosporidium oocysts were found in 16.7% of the unseeded environmental samples, and concentrations, adjusted for recoveries, ranged from 4 to 80 oocysts per 10 liters. Determining recovery efficiency also provided data to calculate detection limits; these ranged from <2 to <215 oocysts per 10 liters. Recoveries of oocysts ranged from 2.0 to 61% for viable oocysts and from 3.0 to 59% for modified oocysts. The recoveries between the two seeding procedures were highly correlated (r = 0.802) and were not significantly different. Recoveries by using modified oocysts, therefore, were comparable to recoveries by using conventional seeding procedures.