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HMB202H1 Study Guide - Quiz Guide: 16S Ribosomal Rna, Paper Towel, Antibacterial Soap

Human Biology
Course Code
Ron Wilson
Study Guide

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The machines used to make paper towels can be contaminated and so can the end paper towel
products be contaminated.
The bacteria community of 6 different unused paper towel brands was determined by culture
methods and by sequencing the 16S ribosomal DNA of the bacteria (used PCR to amplify first).
They then investigated the possible airborne and direct contact transmissions of the bacteria
contaminants during hand drying.
Founds lots of bacteria with bacteria belonging to the bacillus genus the most common followed
by Paenibacillus, Exiguobacterium, and Clostridium (17 different species were found). Paper
towels from recycled fibers had between 100-1000x more bacteria than the non-recycled brand
(virgin pulp wood). No evidence of bacterial airborne transmission was observed during paper
towel dispensing.
Paper towels are made of cellulose, lignin, and other nutrients suitable for bacteria growth.
Strains from the genera Aeromonas, Bacillus, Enterobacter, Microbacterium, Pseudomonas and
Staphylococcus have been isolated from papermaking machinery (which contribute to slime
formation in the machinery).
The main sources of microbiological contamination in paper mills comes from the recycled
waters, the raw materials used, parts of machinery, and the factory environment. Although most
bacteria will be killed in the mill dryers, heat-resistant ones would survive and thus contaminate
the machinery and paper products (like the ones in the abstract).
A previous experiment showed students who had washed their hands with water, regular soap, or
antibacterial soap had more bacteria on their hands after washing and using paper towels than
before. The only exception was students who had used an alcohol-based hand sanitizer instead.
Purpose of the experiment in this article: Determine the extent of bacteria contamination of
various paper towel brands and to isolate the cultures on them. Also investigate the possible
airborne and direct contact transmission of these bacteria contaminants during paper dispensing
and after handwashing, respectively.
Method of getting bacteria from paper to towel: Have worker wear nitrile gloves and spray them
with 70% ethanol solution, rub his hands for 15 seconds and air-dry for 2 minutes. Then
submerge hands in sterile distilled water for 15 seconds before using 3 sheets of paper towel (1
sheet at a time) to dry hands. To grab a sample of the bacteria from the hands get the middle of
the left palm as well as middle of second, third, and fourth fingers to sample on contact agar
plates containing TSA medium. Control samples were done the same way but with air-drying for
3 minutes (instead of paper towel)
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