Inactivating Effects of Common Laboratory Disinfectants, Fixatives, and Temperatures on the Eggs of Soil Transmitted Helminths

Journal Publication ResearchOnline@JCU
Kines, Kristine J.;Fox, Mark;Ndubuisi, MacKevin;Verocai, Guilherme G.;Cama, Vitaliano;Bradbury, Richard
Abstract

Soil-transmitted helminths (STH) are important and widespread intestinal pathogens of humans and animals. It is presently unknown which inactivating procedures may be universally effective for safe transport, preservation, and disinfection of STH-contaminated specimens, and this lack of knowledge may expose laboratory staff to higher risk of laboratory-acquired infections (LAI’s). There are limited data on the efficacy of commonly used disinfectants and fecal fixatives for inactivating the eggs of STH. This work tested five disinfectants for surface cleanup, four storage temperature conditions, and six transport/storage fixatives, to inactivate eggs of three species of STH of animal origin (Ascaris suum “roundworm,” Trichuris vulpis “whipworm” and Ancylostoma caninum “hookworm”) as surrogates for human STH. Among disinfectants, exposure to 10% povidone-iodine for ≥5 min inactivated 100% of the three species tested, while 5 min exposure to 95% ethanol inactivated T. vulpis and A. caninum eggs. All of the fixatives tested had inactivation effects on A. caninum hookworm eggs within 24 h of exposure, except potassium dichromate, which required 48 h. 95% ethanol for ≥48 h inactivated eggs from all three STH species. Freezing at ≤−20°C for ≥24 h inactivated eggs of T. vulpis and A. caninum, but only freezing at −80°C for ≥24 h inactivated >99% eggs, including A. suum. This work provides an evidence base for health and safety guidelines and mitigation strategies for the handling, storage, and disposal of stool samples containing STH eggs in laboratory, health care, childcare, or veterinary settings.

Journal

Microbiology Spectrum

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Volume

9

ISBN/ISSN

2165-0497

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Issue

3

Pages Count

13

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Publisher

American Society for Microbiology

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DOI

10.1128/Spectrum.01828-21