Transcript YoB.4.08
Books as Fomites: how much ‘culture’ can one good book provide? Jay Watson Dara Wegman-Geedey, PhD Year of the Book presentation 16 April 2008 First things first…. WHAT is a fomite? Current usage: a fomite is any inanimate object that transfers pathogens from one host to another or from a natural reservoir to a susceptible host Origins: The word fomite is a back-formation from the plural fomites, which was originally the Latin plural of the singular, fomes, literally meaning “touchwood” or “tinder.” In classical Latin, fomites was pronounced like a concatenation of English "foe" + "me" + "tays"; but "foe" + "mites" has now become a common pronunciation, and "fomite" (also pronounced with a long 'i') is the singular form in English. (http://en.wikipedia.org/wiki/Fomites) Properties of “good” fomites… Varies for bacteria, but in general: non-porous surfaces moderate humidity (approx 45-65%) must also consider cell walls, endospores, possible VNC status Varies widely for viruses, but in general: non-porous surfaces moderate humidity (approx 45-50%) presence of microbes A brief history of books as fomites…. Mostly anecdotal from late 1800s/early 1900s – no definite study data Diphtheria in US: 2 children handling books at a farmhouse where diphtheria had been present years prior Smallpox in US: 1 person borrowing books from a library in neighboring town where a smallpox outbreak had occurred Scarlet fever in US: 1 person from book in which “a young sufferer had used pieces of his peeling skin as bookmarks” streptococci/pneumococci in France: lab isolations from books handled by infected patients Ringworm from XIVth century parchment, Yucel & Kantarcioglu, 1998 Books/paper as fomites in popular culture Microban folders, local Staples, 2007 Microbeguard’s Food Touch paper liners, AP release Jan 2007 Seinfeld episode: “The Bookstore,” April 1998 Paper currency, Pope et al., 2002 England/Wales Public Health (Control of Disease) Act, 1984, Atensteadt, 2006 Paper towel litter, Harrison, et al., 2003 Our questions… Would the environmental conditions of the library support growth of pathogens? Would the conditions in special collections differ in support of pathogen growth compared to the standard library stacks? Would the physical make-up of a book (e.g., cloth vs paper) affect the survival of pathogens? Would survival of pathogens differ on various types of information storage materials? books, periodicals, microfilm. microfiche Effect of Library Environment on Pathogen Growth Environment of each floor and Special Collections was evaluated from at least 10 positions to find average temperature, humidity, light Representative incubation sites chosen: 2nd floor stacks, special collections, control in lab incubator Staphylococcus aureus, S. epidermidis and Escherichia coli stock cultures were grown overnight in tryptic soy broth Diluted samples of S. aureus, S. epidermidis and E. coli were spread plated separately on tryptic soy agar plates Replicates made for placement in each incubation area TSA plates were evaluated daily for three days Colonies counted by visual examination of the plates Library Environs Results, Control Growth of Model Pathogens in Microbiology Lab Incubator 12 10 # of Colonies (log10) 8 6 4 2 0 12/18/2007 S. aureus 12/19/2007 S. epidermidis 12/20/2007 E. coli Control Library Environs Results, part 2 Growth of Model Pathogens in the 2nd Floor Stacks of Tredway Library 10 9 8 # of Colonies (log10) 7 6 5 4 3 2 1 0 12/18/2007 S. aureus 12/19/2007 S. epidermidis 12/20/2007 Lab Incubation E. coli Control Library Environs Results, part 3 Growth of Model Pathogens in Special Collections of Tredway Library 10 9 8 # of Colonies (log10) 7 6 5 4 3 2 1 0 12/18/2007 S. aureus 12/19/2007 S. epidermidis 12/20/2007 Lab Incubation E. coli Control Library Environment Conclusions Library and special collections environmental conditions support growth of a Gram negative organism (E. coli) but fail to support growth of Gram positive bacteria (Staphylococcus sp.) But these conditions don’t kill the Gram positive organisms either. Returning them to optimal conditions resulted in maximum expected growth. Effect of Materials on Pathogen Survival Store-bought spray bottles were evaluated and calibrated for delivery of appropriate “spritz” size S. aureus and E. coli cultures were grown overnight in TSB Books, periodicals, microfilm and microfiche (substrates) “retired” from the library were inoculated with either diluted spritzes of S. aureus or E. coli Substrates were immediately sampled using PetriFilm direct contact method to determine survival of model pathogens Sampling repeated at one week intervals for a one month period Materials Effect on Survival Results Magazin e Book 1 Prelim One Two 2 Film 1 2 CD 1 2 Fiche 1 2 S. aureus ++ ++ +++ +++ + + +++ +++ +++ E. coli + ++ ++ + + + +++ +++ ++ S. aureus + + ++ ++ + + ++ ++ +++ E. coli + + + + + + + + - S. aureus + + ++ + + + +++ ++ ++ E. coli + - + - + + + - - Materials Effect on Survival Conclusions (in progress) Survival on non-porous surfaces appears better than on non-porous for both model organisms Survival of Gram positive S. aureus appears better on all surfaces than the Gram negative E. coli The take-home message…. WASH your hands after handling potential fomites use liquid handsoap that does not contain Triclosan or other antimicrobials don’t need to select for the strong ones, just need to remove bacteria from your hands 30 seconds: “Happy Birthday” twice all surfaces, under nails Alcohol-based hand sanitizers okay – but only if no running water available Acknowledgements Student researchers: Rihana Al-Ghalayini ‘09 Christine Bridge ’08 Jay Watson ’08 Special thanks: to the library staff for donating “retired” books, journals, microfilm and microfiche from the Tredway Library collection. and to Alyssa Tillary ‘10 who helped plate cultures for the environmental conditions study in the library. and to 3M for the first 200 PetriFilms: donated as part of the 3M Microbiology University Program.