Chloe Evetts (8990-4674)
Microorganisms are of abundance and located virtually everywhere on planet earth.
These organisms, much smaller than the eye can perceive, are considerably diverse. As
potentially pathogenic, such as the carbapenem-resistant Enterobacteriaceae (CRE)
(figure a), and/or beneficial, like the gut flora of the human intestines (figure b),
microorganisms need to be studied in depth to understand what is causing diseases
and what is helping animals thrive. Studying microorganisms involves the application of
various aseptic techniques which allows us to work with non-contaminated specimen.
The purpose of this lab is to learn the various aseptic techniques that come with
studying bacteria, apply those techniques to collecting microbial specimen from the air,
from our body, and from around the room, and properly culture the bacteria on agar
Figure Figure b
Due to the countless number of microorganisms present at any given time, exposure of
the agar plates to the air will allow species to accumulate on the plate. Incubation of
these plates will promote growth and colonies can then be studied.
Sterile swabs will also easily collect numerous specimen from around the room and on
our body. Incubation of these plates will promote growth and colonies can then be
Procedure: Five totalagarplates wereused,threeof whichwerebrainheart infusionagar (BHI)
plates,capableof growingbacteria,andtwoofwhichwere PotatoDextroseAgar (PDA)
plates,capableof growingfungiandyeast.Eachplate was labeledonthebottomwitha
permanent markerandour initials,date,mediatype.OnePDAandoneBHIplate were
labeled“openlid” (FigureC),oneBHIplate withalinedrawnthroughthemiddlewas
labeledwithaselectedbodypart oneachside,one BHIplate withaline drawnthrough
themiddlewaslabeledwithdifferentselectedareasof theenvironment oneachside,and
one PDAplate withalinedrawnthroughthemiddlewaslabeledwithdifferentselected
Figure c Figure d
The open lid plates were left open until the end of class in order to maximize specimen
collected. The body plates were swabbed with samples taken from the cheek and from
behind an ear. The environment plates were swabbed with samples from a cell phone
and a shoe. The dusty plates were swabbed with samples from the sink handle and the
sink drain. The plates were then closed, making sure to tape the PDA plates and
inverting only the BHA plates, and then placed in the incubator.
Results: In the Air:
Circular, irregular and punctiform
Sample left open for 1 hour
In the Environment:
Right: cell phone
Circular, irregular, filamentous, and punctiform
On Me: OnMe:
Left: cheek swab
Right: behind the ear
After letting our petri dishes incubate for 48 hours, it was shocking how many different
colonies grew from our samples. Our hypothesis was correct in that incubating plates
will indeed promote the growth of many different microorganisms. There are a multitude
of different organisms present all around us, including our cell phones, shoes, cheeks
and behind our ears. The most shocking was the amount of growth present on the dish
that was just left open in the air. There was some variety in colors and sizes amongst
the different samples. Some were yellow, others white, some slightly translucent. There
were also some fungi present. Between the different samples, the shoe sample
provided the most abundant amount of different bacteria. It is very interesting to see the
abundance of different bacteria and microbes that live all around us on things we touch
• Nosocomial: Hospital Acquired infection (HAI)
• Aseptic: Free from contamination caused by harmful microorganisms • Brain heart infusion agar: enriched non-selective medium for the isolation and
cultivation of most anaerobic bacteria and other fastidious microorganisms
• Potato Dextrose agar: nonselective medium for the cultivation of yeasts and
• Antibiotic: agent that inhibits bacterial growth or kills bacteria.
• Archaea: The Archaea constitute a domain of single-celled microorganisms.
These microbes have no cell nucleus or any other membrane-bound organelles
within their cells.
• Athlete’s foot: Athlete's foot is an infection of the feet caused by fungus. The
medical term is tinea pedis. Athlete's foot may last for a short or long time and
may come back after treatment.
• Bacillus subtilis: Bacillus subtilis, known also as the hay bacillus or grass bacillus,
is a Gram-positive, catalase-positive bacterium.
• Bacteria: Bacteria constitute a large domain of prokaryotic microorganisms.
Typically a few micrometres in length, bacteria have a wide range of shapes,
ranging from spheres to rods and spirals.
• Bacteriodes: Bacteroides is a genus of Gram-negative, bacillus bacteria.
Bacteroides species are non-endospore-forming, anaerobes, and may be either
motile or non-motile, depending on the species. The DNA base composition is
• Bacteriophage: A bacteriophage is a virus that infects and replicates within
bacteria. The term is derived from 'bacteria' and the Greek φαγεῖν phagein "to
• Biodiversity: the degree of variation of life forms within a given species,
ecosystem, biome, or planet.
• Chicken pox: Chickenpox is a viral infection in which a person develops
extremely itchy blisters all over the body. It