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Transient flora on hands as a vehicle of transmission to food for Staphylococcus aureus Elissa Redmiles and Lucy Erickson.

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Presentation on theme: "Transient flora on hands as a vehicle of transmission to food for Staphylococcus aureus Elissa Redmiles and Lucy Erickson."— Presentation transcript:

1 Transient flora on hands as a vehicle of transmission to food for Staphylococcus aureus Elissa Redmiles and Lucy Erickson

2 Background History of food bourn illness Hypothesis

3 History of food borne illness Since the beginning of human history, food borne illness has been an issue Various food preservation methods have been employed over the years to slow down food spoilage by microbes and natural aging processes, some common prevention methods include: drying freezing freeze-drying salting curing canning pickling irradiation treating with sugar treating with inert gases (such as carbon dioxide) S

4 Transient flora found on human skin and hands plays an important role in food contamination Transient flora found on human skin and hands plays an important role in food contamination When those involved in food preparation fail to observe hygienic methods When those involved in food preparation fail to observe hygienic methods History of food borne illness (cont.)

5 It is hypothesized that Staphylococcus aureus, a microbe occurring naturally on the hands of some people, would be found at various locations throughout the Microbiology building It is hypothesized that Staphylococcus aureus, a microbe occurring naturally on the hands of some people, would be found at various locations throughout the Microbiology building It was also hypothesized that many different types of bacteria would be isolated from the various locations tested It was also hypothesized that many different types of bacteria would be isolated from the various locations testedHypothesis

6 Hypothesis (cont.) The isolation of bacteria from the inside handle of the bathroom door particularly holds implications for food hygiene, as ideally it should only be touched by pristinely washed hands. The isolation of bacteria from the inside handle of the bathroom door particularly holds implications for food hygiene, as ideally it should only be touched by pristinely washed hands.

7 Protocol Design and Detailed Methods Overall approach and rationale for approach Overall approach and rationale for approach Detailed methods and rationale behind methods Detailed methods and rationale behind methods Expected results Expected results

8 Overall approach and rationale for approach There were 2 objectives for this experiment: There were 2 objectives for this experiment: To determine the number of different types of bacteria that live on each of 7 objects tested To determine the number of different types of bacteria that live on each of 7 objects tested To identify on which objects To identify on which objects Staphylococcus aureus is present

9 Overall approach and rationale for approach (cont.) To achieve these objectives a growth medium was required To achieve these objectives a growth medium was required Both agar and broth were considered Both agar and broth were considered Agar was determined to be a more suitable growth medium since: Agar was determined to be a more suitable growth medium since: It allows direct observation of different types of bacterial colonies It allows direct observation of different types of bacterial colonies It prohibits the number of bacteria on an object from being determined It prohibits the number of bacteria on an object from being determined Broth was determined to be a less suitable growth medium because: Broth was determined to be a less suitable growth medium because: It allows the number of bacteria on an object to be determined It allows the number of bacteria on an object to be determined It does not allow direct observation of different types of bacterial colonies It does not allow direct observation of different types of bacterial colonies

10 To achieve the first objective a sampling technique was required To achieve the first objective a sampling technique was required Both saline wetted and dry sterile cotton swabs were considered: Both saline wetted and dry sterile cotton swabs were considered: Wet cotton swabs were determined to be most effective for obtaining the largest sample of microorganisms Wet cotton swabs were determined to be most effective for obtaining the largest sample of microorganisms Microorganisms adhere more readily to wet surfaces Microorganisms adhere more readily to wet surfaces A swab and streak method was used to inoculate the agar plates A swab and streak method was used to inoculate the agar plates Overall approach and rationale for approach (cont.)

11 To achieve the second objective a method of differentiating Staphylococcus aureus was needed: To achieve the second objective a method of differentiating Staphylococcus aureus was needed: Differential mediums and assays were used: Differential mediums and assays were used: The gram stain was used to differentiate gram negative organisms from gram positive organisms The gram stain was used to differentiate gram negative organisms from gram positive organisms The catalase assay was used to differentiate Staphylococci (positive result) from Streptococci (negative result) The catalase assay was used to differentiate Staphylococci (positive result) from Streptococci (negative result) Blood Agar was used to differentiate S. aureus (positive result) from S. epidermis (negative result) Blood Agar was used to differentiate S. aureus (positive result) from S. epidermis (negative result) Mannitol Salt Agar was used to differentiate S. aureus (positive result) from S. epidermis (negative result) Mannitol Salt Agar was used to differentiate S. aureus (positive result) from S. epidermis (negative result) The CoAgulase assay was used to differentiate S. aureus (positive result) from S. epidermis (negative result) The CoAgulase assay was used to differentiate S. aureus (positive result) from S. epidermis (negative result) Overall approach and rationale for approach (cont.)

12 Day 1 Day 1 Made Mannitol Salt Agar Made Mannitol Salt Agar Autoclaved and cooled medium Autoclaved and cooled medium Day 2 Day 2 Poured Mannitol Salt Agar plates Poured Mannitol Salt Agar plates Day 3 Day 3 Obtained Trypticase Soy Agar (TSA) plates Obtained Trypticase Soy Agar (TSA) plates Obtained a package of sterile cotton swabs, and a tube of diluted saline Obtained a package of sterile cotton swabs, and a tube of diluted saline Swabbed 7 objects: Swabbed 7 objects: Bathroom sink faucet (1st floor) Bathroom sink faucet (1st floor) Bathroom (interior) doorknob (1st floor) Bathroom (interior) doorknob (1st floor) Micro bench sink faucet (Room x) Micro bench sink faucet (Room x) Front door handle—Micro building Front door handle—Micro building Handicapped door button—Micro building Handicapped door button—Micro building Computer mouse in lab Computer mouse in lab Stair rail (1st floor) Stair rail (1st floor) Detailed Methods

13 Day 3 (cont.) Day 3 (cont.) Swabbing method used: Swabbing method used: Dipped tip of sterile swab into saline Dipped tip of sterile swab into saline Swabbed 1 of 7 objects Swabbed 1 of 7 objects Struck inoculated swab on sterile agar plate with zigzag motion Struck inoculated swab on sterile agar plate with zigzag motion A new swab was used for each plate A new swab was used for each plate 4 plates (2 TSA and 2 Mannitol Salt Agar) were used for each object 4 plates (2 TSA and 2 Mannitol Salt Agar) were used for each object Discarded the swab Discarded the swab Incubated all plates at 37°C for 48 hours Incubated all plates at 37°C for 48 hours Detailed Methods (cont.)

14 Day 4 Day 4 Observed growth of different colony types on TSA plates Observed growth of different colony types on TSA plates Observed growth of colonies on Mannitol Salt Agar plates Observed growth of colonies on Mannitol Salt Agar plates Observed fermentation Observed fermentation Photographed certain colonized plates Photographed certain colonized plates Counted and recorded different types of colonies Counted and recorded different types of colonies Selected different types of colonies from each Mannitol Salt Agar plate Selected different types of colonies from each Mannitol Salt Agar plate Struck the selected colonies on (new) Mannitol Salt Agar plates, on (new) TSA plates, and on (new) Blood Agar plates Struck the selected colonies on (new) Mannitol Salt Agar plates, on (new) TSA plates, and on (new) Blood Agar plates Incubated all plates at 37°C for 24 hours Incubated all plates at 37°C for 24 hours Detailed Methods (cont.)

15 Day 5 Day 5 Observed Mannitol Salt Agar plates Observed Mannitol Salt Agar plates Observed fermentation Observed fermentation Observed TSA plates Observed TSA plates Observed Blood Agar plates Observed Blood Agar plates Observed hemolysis Observed hemolysis Performed catalase assay on pure Performed catalase assay on pure colonies isolated from Mannitol Salt Agar plates Performed gram stain on pure colonies isolated from Mannitol Salt Agar plates Performed gram stain on pure colonies isolated from Mannitol Salt Agar plates Performed CoAgulase assay on certain pure colonies isolated from Mannitol Salt Agar plates Performed CoAgulase assay on certain pure colonies isolated from Mannitol Salt Agar plates Bactistaph latex 150 test Bactistaph latex 150 test Photographed relevant results Photographed relevant results Day 6 Day 6 Observed results from CoAgulase assay Observed results from CoAgulase assay Detailed Methods (cont.)

16 Day 3 Day 3 Saline was used: Saline was used: To maintain highest degree of sterility To maintain highest degree of sterility Since bacteria adhere more readily to wet surfaces than to dry surfaces Since bacteria adhere more readily to wet surfaces than to dry surfaces In a diluted form so growth of non-salt tolerant organisms was uninhibited In a diluted form so growth of non-salt tolerant organisms was uninhibited A new swab was used for each plate to reduce the risk of contamination by organisms not found on objects of interest A new swab was used for each plate to reduce the risk of contamination by organisms not found on objects of interest TSA plates were used: TSA plates were used: As a control As a control To determine the different types of organisms on objects of interest To determine the different types of organisms on objects of interest Detailed Rationale Behind Methods

17 Detailed Rationale (cont.) Day 3 (cont.) Day 3 (cont.) Mannitol Salt Agar plates were used: Mannitol Salt Agar plates were used: To isolate Staphylococcus aureus from objects of interest To isolate Staphylococcus aureus from objects of interest Staphylococcus aureus is a salt tolerant organism that grows on Mannitol Salt Agar while other non-salt tolerant organisms will not grow Staphylococcus aureus is a salt tolerant organism that grows on Mannitol Salt Agar while other non-salt tolerant organisms will not grow All plates were incubated at 37°C for 48 hours: All plates were incubated at 37°C for 48 hours: 37°C is in the optimal growth temperature range for organisms that could be found on objects of interest 37°C is in the optimal growth temperature range for organisms that could be found on objects of interest 48 hours is in the optimal growth time range for organisms that could be found on objects of interest 48 hours is in the optimal growth time range for organisms that could be found on objects of interest 4 plates (2 TSA and 2 Mannitol Salt Agar) were used: 4 plates (2 TSA and 2 Mannitol Salt Agar) were used: To safeguard from error To safeguard from error If an error occurred with one “set” (1 TSA and 1 Mannitol Salt Agar plate) results could be obtained from another “set” (theoretically void of error) If an error occurred with one “set” (1 TSA and 1 Mannitol Salt Agar plate) results could be obtained from another “set” (theoretically void of error)

18 Detailed Rationale (cont.) Day 4 Day 4 Different colonies from each TSA plate were struck on (new) TSA plates to confirm that colonies selected were pure and different from other colonies on the plate Different colonies from each TSA plate were struck on (new) TSA plates to confirm that colonies selected were pure and different from other colonies on the plate Struck colonies from Mannitol Salt Agar on (new) Mannitol Salt Agar plates to isolate pure colonies for further tests and to confirm that colonies isolated were Staphylococcus aureus Struck colonies from Mannitol Salt Agar on (new) Mannitol Salt Agar plates to isolate pure colonies for further tests and to confirm that colonies isolated were Staphylococcus aureus Staphylococcus aureus ferments Mannitol producing a yellow zone surrounding colony Staphylococcus aureus ferments Mannitol producing a yellow zone surrounding colony

19 Detailed Rationale (cont.) Day 4 (cont.) Day 4 (cont.) Struck colonies from Mannitol Salt Agar on (new) TSA plates as a control Struck colonies from Mannitol Salt Agar on (new) TSA plates as a control Isolated colonies were struck on Blood Agar to confirm that isolated colonies were Staphylococcus aureus Isolated colonies were struck on Blood Agar to confirm that isolated colonies were Staphylococcus aureus Staphylococcus aureus has  -hemolysis on Blood Agar Staphylococcus aureus has  -hemolysis on Blood Agar

20 Detailed Rationale (cont.) Day 5 Day 5 Catalase test was performed to: Catalase test was performed to: Confirm that cultures from Mannitol Salt Agar plates were Staphylococci (positive) not Streptococci (negative) Confirm that cultures from Mannitol Salt Agar plates were Staphylococci (positive) not Streptococci (negative) Indicating that cultures were Staphylococcus aureus Indicating that cultures were Staphylococcus aureus Gram stain was performed to: Gram stain was performed to: Confirm that cultures from Mannitol Salt Agar plates were gram positive not gram negative Confirm that cultures from Mannitol Salt Agar plates were gram positive not gram negative Indicating that cultures were Staphylococcus aureus Indicating that cultures were Staphylococcus aureus Confirm that bacteria colonized on Mannitol Salt Agar plates formed clusters not chains Confirm that bacteria colonized on Mannitol Salt Agar plates formed clusters not chains Indicating that cultures were Staphylococcus aureus Indicating that cultures were Staphylococcus aureus

21 Detailed Rationale (cont.) Day 5 (cont.) Day 5 (cont.) Bacti Staph Latex 150 test was performed to: Bacti Staph Latex 150 test was performed to: Confirm that isolated colonies tested positive not negative for agglutination Confirm that isolated colonies tested positive not negative for agglutination Indicating that the cultures were Staphylococcus aureus Indicating that the cultures were Staphylococcus aureus CoAgulase assay was performed to: CoAgulase assay was performed to: Confirm that isolated colonies were CoAgulase positive not CoAgulase negative Confirm that isolated colonies were CoAgulase positive not CoAgulase negative Indicating that the cultures were Staphylococcus aureus Indicating that the cultures were Staphylococcus aureus

22 Expected Results It was expected that: It was expected that: Numerous types of microorganisms would live on the tested objects Numerous types of microorganisms would live on the tested objects Staphylococcus aureus is found on some human hands and would therefore be present on some of the tested objects Staphylococcus aureus is found on some human hands and would therefore be present on some of the tested objects

23 Results Findings Findings Summary of Findings Summary of Findings Relationship of findings to expectations Relationship of findings to expectations

24 TSA plate 1 was inoculated with microorganisms from the bathroom sink faucet: TSA plate 1 was inoculated with microorganisms from the bathroom sink faucet: 7 small white colonies grew 7 small white colonies grew 8 large white colonies grew 8 large white colonies grew TSA plate 2 was inoculated with microorganisms from the bathroom sink faucet: TSA plate 2 was inoculated with microorganisms from the bathroom sink faucet: 16 small white colonies grew 16 small white colonies grew 31 large white colonies grew 31 large white colonies grew Mannitol Salt Agar plate 1 was inoculated with microorganisms from the bathroom sink faucet: Mannitol Salt Agar plate 1 was inoculated with microorganisms from the bathroom sink faucet: 2 small white colonies grew 2 small white colonies grew Mannitol Salt Agar plate 2 was inoculated with microorganisms from the bathroom sink faucet: Mannitol Salt Agar plate 2 was inoculated with microorganisms from the bathroom sink faucet: No growth No growth Findings

25 TSA plate 1 was inoculated with microorganisms from the computer mouse: TSA plate 1 was inoculated with microorganisms from the computer mouse: No growth No growth TSA plate 2 was inoculated with microorganisms from the computer mouse: TSA plate 2 was inoculated with microorganisms from the computer mouse: 1 small white colonies grew 1 small white colonies grew 1 medium white colonies grew 1 medium white colonies grew Mannitol Salt Agar plate 1 was inoculated with microorganisms from the computer mouse: Mannitol Salt Agar plate 1 was inoculated with microorganisms from the computer mouse: 2 small white colonies grew 2 small white colonies grew 3 large peaked colonies grew 3 large peaked colonies grew Mannitol Salt Agar plate 2 was inoculated with microorganisms from the computer mouse: Mannitol Salt Agar plate 2 was inoculated with microorganisms from the computer mouse: No growth No growth Findings (cont.)

26 TSA plate 1 was inoculated with microorganisms from the stair rail: TSA plate 1 was inoculated with microorganisms from the stair rail: No growth No growth TSA plate 2 was inoculated with microorganisms from the stair rail: TSA plate 2 was inoculated with microorganisms from the stair rail: No growth No growth Mannitol Salt Agar plate 1 was inoculated with microorganisms from the stair rail: Mannitol Salt Agar plate 1 was inoculated with microorganisms from the stair rail: 1 small white colony grew 1 small white colony grew 1 large colony with yellow zone grew 1 large colony with yellow zone grew Mannitol Salt Agar plate 2 was inoculated with microorganisms from the stair rail: Mannitol Salt Agar plate 2 was inoculated with microorganisms from the stair rail: No growth No growth Findings (cont.)

27 TSA plate 1 was inoculated with microorganisms from the handicapped button: TSA plate 1 was inoculated with microorganisms from the handicapped button: 1 small yellow colony grew 1 small yellow colony grew TSA plate 2 was inoculated with microorganisms from the handicapped button: TSA plate 2 was inoculated with microorganisms from the handicapped button: 1 small white colony grew 1 small white colony grew Mannitol Salt Agar plate 1 was inoculated with microorganisms from the handicapped button: Mannitol Salt Agar plate 1 was inoculated with microorganisms from the handicapped button: No growth No growth Mannitol Salt Agar plate 2 was inoculated with microorganisms from the handicapped button: Mannitol Salt Agar plate 2 was inoculated with microorganisms from the handicapped button: No growth No growth Findings (cont.)

28 TSA plate 1 was inoculated with microorganisms from front door knob: TSA plate 1 was inoculated with microorganisms from front door knob: 33 small yellow colonies grew 33 small yellow colonies grew 1 medium white colony grew 1 medium white colony grew TSA plate 2 was inoculated with microorganisms from the front door knob: TSA plate 2 was inoculated with microorganisms from the front door knob: 1 small white colony grew 1 small white colony grew Mannitol Salt Agar plate 1 was inoculated with microorganisms from the front door knob: Mannitol Salt Agar plate 1 was inoculated with microorganisms from the front door knob: No growth No growth Mannitol Salt Agar plate 2 was inoculated with microorganisms from the front door knob: Mannitol Salt Agar plate 2 was inoculated with microorganisms from the front door knob: No growth No growth Findings (cont.)

29 TSA plate 1 was inoculated with microorganisms from bathroom door knob: TSA plate 1 was inoculated with microorganisms from bathroom door knob: 3 small yellow colonies grew 3 small yellow colonies grew 1 small white colony grew 1 small white colony grew 1 medium white colony grew 1 medium white colony grew TSA plate 2 was inoculated with microorganisms from the bathroom door knob: TSA plate 2 was inoculated with microorganisms from the bathroom door knob: 7 small white colonies grew 7 small white colonies grew 9 large white colonies grew 9 large white colonies grew Mannitol Salt Agar plate 1 was inoculated with microorganisms from the bathroom door knob: Mannitol Salt Agar plate 1 was inoculated with microorganisms from the bathroom door knob: 2 medium colonies with yellow zones grew 2 medium colonies with yellow zones grew 2 large peaked colonies grew 2 large peaked colonies grew Mannitol Salt Agar plate 2 was inoculated with microorganisms from the bathroom door knob: Mannitol Salt Agar plate 2 was inoculated with microorganisms from the bathroom door knob: No growth No growth Findings (cont.)

30 TSA plate 1 was inoculated with microorganisms from lab sink: TSA plate 1 was inoculated with microorganisms from lab sink: No growth No growth TSA plate 2 was inoculated with microorganisms from the bathroom door knob: TSA plate 2 was inoculated with microorganisms from the bathroom door knob: No growth No growth Mannitol Salt Agar plate 1 was inoculated with microorganisms from the bathroom door knob: Mannitol Salt Agar plate 1 was inoculated with microorganisms from the bathroom door knob: 1 small white colony grew 1 small white colony grew Mannitol Salt Agar plate 2 was inoculated with microorganisms from the bathroom door knob: Mannitol Salt Agar plate 2 was inoculated with microorganisms from the bathroom door knob: No growth No growth Findings (cont.)

31 A Mannitol Salt Agar plate was inoculated with microorganisms from the bathroom door handle: A Mannitol Salt Agar plate was inoculated with microorganisms from the bathroom door handle: Growth and fermentation on Mannitol plate Growth and fermentation on Mannitol plate Gram positive rods Gram positive rods Snapping replication was observed Snapping replication was observed Catalase positive Catalase positive A Mannitol Salt Agar plate was inoculated with microorganisms from the bathroom sink: A Mannitol Salt Agar plate was inoculated with microorganisms from the bathroom sink: Growth and fermentation on Mannitol plate Growth and fermentation on Mannitol plate Gram positive cocci organized in grape like clusters Gram positive cocci organized in grape like clusters Catalase positive Catalase positive Findings (cont.)

32 A Mannitol Salt Agar plate was inoculated with microorganisms from the stair rail: A Mannitol Salt Agar plate was inoculated with microorganisms from the stair rail: Growth and fermentation on Mannitol plate Growth and fermentation on Mannitol plate Gram positive rods Gram positive rods Snapping replication was observed Snapping replication was observed Catalase negative Catalase negative A Mannitol Salt Agar plate was inoculated with microorganisms from the computer mouse: A Mannitol Salt Agar plate was inoculated with microorganisms from the computer mouse: Growth and fermentation on Mannitol plate Growth and fermentation on Mannitol plate Gram positive rods Gram positive rods Snapping replication was observed Snapping replication was observed Catalase positive Catalase positive Findings (cont.)

33 A Blood Agar plate was inoculated with microorganisms from the bathroom door handle: A Blood Agar plate was inoculated with microorganisms from the bathroom door handle: Growth on Blood Agar Growth on Blood Agar β-hemolysis β-hemolysis A Blood Agar plate was inoculated with microorganisms from the bathroom sink: A Blood Agar plate was inoculated with microorganisms from the bathroom sink: Growth on Blood Agar Growth on Blood Agar β -hemolysis β -hemolysis A Blood Agar plate was inoculated with microorganisms from the stair rail: A Blood Agar plate was inoculated with microorganisms from the stair rail: Growth on Blood Agar Growth on Blood Agar β -hemolysis β -hemolysis A Blood Agar plate was inoculated with microorganisms from the computer mouse: A Blood Agar plate was inoculated with microorganisms from the computer mouse: Growth on Blood Agar Growth on Blood Agar α-hemolysis α-hemolysis Findings (cont.)

34 Microorganisms isolated from the objects exhibited a variety of phenotypes when grown on TSA plates: Microorganisms isolated from the objects exhibited a variety of phenotypes when grown on TSA plates: Small white bacterial colonies Small white bacterial colonies Small yellow bacterial colonies Small yellow bacterial colonies Medium white bacterial colonies Medium white bacterial colonies Large white bacterial colonies Large white bacterial colonies The phenotypes above indicate that a very diverse bacterial population is present on the tested objects The phenotypes above indicate that a very diverse bacterial population is present on the tested objects This data supports the first hypothesis that numerous types of microorganisms would live on tested objects This data supports the first hypothesis that numerous types of microorganisms would live on tested objects Summary of Findings

35 Microorganisms isolated from the: Microorganisms isolated from the: Stair rail Stair rail Computer mouse Computer mouse Bathroom door handle Bathroom door handle Are suspected to be Cornyebacteria since: Are suspected to be Cornyebacteria since: They undergo snapping They undergo snappingreplication Form “Chinese letters” Form “Chinese letters” Are gram positive rods Are gram positive rods This was not hypothesized This was not hypothesized Summary of Findings (cont.)

36 Microorganisms isolated from the bathroom sink are suspected to be Staphylococcus aureus Microorganisms isolated from the bathroom sink are suspected to be Staphylococcus aureus The samples are strongly suspected to be Staphylococcus aureus since: The samples are strongly suspected to be Staphylococcus aureus since: They are gram positive cocci seen in grape-like clusters They are gram positive cocci seen in grape-like clusters Are catalase and CoAgulase positive Are catalase and CoAgulase positive Have β-hemolysis Have β-hemolysis Ferment Mannitol Ferment Mannitol These phenotypes are identical These phenotypes are identical to those exhibited by Staphylococcus aureus This supports the second hypothesis: Staphylococcus aureus is found on human hands and would therefore be present on some of the tested objects This supports the second hypothesis: Staphylococcus aureus is found on human hands and would therefore be present on some of the tested objects Summary of Findings (cont.)

37 Discussion Description of Staphylococcus aureus Description of Staphylococcus aureus Why Staphylococcus aureus was expected to be found Why Staphylococcus aureus was expected to be found Incidence of disease Incidence of disease Virulence of Staphylococcus aureus Virulence of Staphylococcus aureus Comments on protocol Comments on protocol Comments on results Comments on results Comments on overall significance of project Comments on overall significance of project

38 Description of Staphylococcus aureus Phenotype Phenotype Gram positive cocci Gram positive cocci Found in pairs, chains, or grapelike-clusters Found in pairs, chains, or grapelike-clusters Produces heat stable enterotoxin Produces heat stable enterotoxin Salt tolerant Salt tolerant Ferments Mannitol Ferments Mannitol Catalase positive Catalase positive CoAgulase Positive CoAgulase Positive

39 Habitat Habitat Air Air Dust Dust Sewage Sewage Environmental surfaces Environmental surfaces 50% of humans (higher in health professionals) 50% of humans (higher in health professionals) Foods Foods Poultry and egg products Poultry and egg products Egg, tuna, potato, and chicken salads Egg, tuna, potato, and chicken salads Milk and dairy products Milk and dairy products Description of Staphylococcus aureus (cont.)

40 Expected to find Staphylococcus aureus various surfaces throughout the microbiology building where the transient flora from many peoples’ hands has been transferred. One of the places swabbed was the inside bathroom door handle, where hopefully only people with freshly washed hands are touching. Unfortunately, this is not always the case, and a diverse population of bacteria were isolated from the door handle. Someone who fails to wash his or her hands upon exiting the restroom is unlikely to remember to wash them before eating or preparing food for another person. Thus, if S. aureus were found on the locations tested it could hold strong ramifications for general human cleanliness, and subsequently, health. Expected to find Staphylococcus aureus various surfaces throughout the microbiology building where the transient flora from many peoples’ hands has been transferred. One of the places swabbed was the inside bathroom door handle, where hopefully only people with freshly washed hands are touching. Unfortunately, this is not always the case, and a diverse population of bacteria were isolated from the door handle. Someone who fails to wash his or her hands upon exiting the restroom is unlikely to remember to wash them before eating or preparing food for another person. Thus, if S. aureus were found on the locations tested it could hold strong ramifications for general human cleanliness, and subsequently, health. Why Staphylococcus aureus was expected to be found

41 Staphylococcus aureus is a component of the normal flora for 50% of all people Staphylococcus aureus is a component of the normal flora for 50% of all people Carriers of Staphylococcus aureus transfer the bacteria to every touched object Carriers of Staphylococcus aureus transfer the bacteria to every touched object Regardless of hand washing Regardless of hand washing In proper growth conditions the bacteria will propagate on objects such as those tested In proper growth conditions the bacteria will propagate on objects such as those tested As Staphylococcus aureus contaminated objects are used, bacteria are transferred to a users transient flora As Staphylococcus aureus contaminated objects are used, bacteria are transferred to a users transient flora Staphylococcus aureus was isolated on tested objects Staphylococcus aureus was isolated on tested objects Thus, hand washing does not preclude the transfer of Staphylococcus aureus to food Thus, hand washing does not preclude the transfer of Staphylococcus aureus to food Why finding Staphylococcus aureus was probable

42 The incidence of illness is difficult to pinpoint due to a number of reasons The incidence of illness is difficult to pinpoint due to a number of reasons Poor response from victims during interviews Poor response from victims during interviews Misdiagnosis (symptoms are very similar to those of Bacillus cereus toxin) Misdiagnosis (symptoms are very similar to those of Bacillus cereus toxin) Inadequate collection of lab samples Inadequate collection of lab samples Improper lab examination Improper lab examination Incidence of disease

43 Causes staphyloenterotoxicosis (food poisoning) Causes staphyloenterotoxicosis (food poisoning) Operates by toxin, not colonization Operates by toxin, not colonization ID 50 – 1.0 microgram ID 50 – 1.0 microgram Onset of illness is rapid and varies based on: Onset of illness is rapid and varies based on: Amount of food ingested Amount of food ingested Amount of toxin present in food Amount of toxin present in food Individual susceptibility Individual susceptibility General health of victim General health of victim Virulence of Staphylococcus aureus

44 Symptoms: Symptoms: Nausea Nausea Vomiting Vomiting Abdominal cramping Abdominal cramping Headache Headache Changes in pressure and blood rates Changes in pressure and blood rates Average recovery time for mild case: Average recovery time for mild case: 2-3 days 2-3 days Virulence of Staphylococcus aureus (cont.)

45 Treatment Treatment Rest Rest Fluids Fluids Medicines to calm stomach Medicines to calm stomach Hospitalization/Intravenous therapy for more severe cases (usually elderly or infants) Hospitalization/Intravenous therapy for more severe cases (usually elderly or infants) Virulence of Staphylococcus aureus (cont.)

46 Prevention Prevention Wash hands and under nails vigorously and often Wash hands and under nails vigorously and often Do not prepare food with an eye or nose infection Do not prepare food with an eye or nose infection Do not serve food to others with open wounds Do not serve food to others with open wounds Keep food preparation areas sanitary Keep food preparation areas sanitary Store cooked food in wide, shallow containers and refrigerate Store cooked food in wide, shallow containers and refrigerate Do not leave food out for long periods of time Do not leave food out for long periods of time Keep hot foods hot (above 140 degrees F) Keep hot foods hot (above 140 degrees F) Keep cold foods cold (40 degrees F or lower) Keep cold foods cold (40 degrees F or lower) Virulence of Staphylococcus aureus (cont.)

47 Comments on Protocol Method of multiple plate inoculation was successful Method of multiple plate inoculation was successful By using 4 plates for each object tested it allowed for confirmation of results By using 4 plates for each object tested it allowed for confirmation of results Saline wetted swab and streak inoculation method was successful: Saline wetted swab and streak inoculation method was successful: Isolated colony growth occurred Isolated colony growth occurred Testing and differential media: Testing and differential media: Catalase Catalase CoAgulase CoAgulase Mannitol Mannitol Blood Blood

48 Comments on Results Comments on Results Comments on Results Found numerous colonies resembling Corynebacteria, a Gram-Positive rod generally found in soil Found numerous colonies resembling Corynebacteria, a Gram-Positive rod generally found in soil Methylene blue staining did not reveal metachromatic granules, however not all species exhibit this trait Methylene blue staining did not reveal metachromatic granules, however not all species exhibit this trait This finding is consistent with concept of bacteria found on unwashed hands This finding is consistent with concept of bacteria found on unwashed hands Unable to identify specific strain of Corynebacteria isolated, since many of the organisms can not be typed easily. Although there have been significant advances in PCR technology, this technology was not available. Unable to identify specific strain of Corynebacteria isolated, since many of the organisms can not be typed easily. Although there have been significant advances in PCR technology, this technology was not available. Isolate from bathroom sink faucet is indicated by tests to be Staphylococcus aureus Isolate from bathroom sink faucet is indicated by tests to be Staphylococcus aureus

49 Comments on overall significance of project This project aims to raise public awareness that pathogenic microorganisms are present on numerous objects touched prior to and after hand washing This project aims to raise public awareness that pathogenic microorganisms are present on numerous objects touched prior to and after hand washing

50 References Boyce, J., Pittet, D. (2002). “Guideline for Hand Hygiene in Health-Care Settings” 1 April Morbidity and Mortality Weekly Report, 51-RR CDC. Outbreak of community-associated methicillin- resistant Staphylococcus aureus skin infections---Los Angeles County, California, Morbidity and Mortality Weekly Report 2006;52:88. U.S. Food and Drug Administration. “Staphylococcus aureus.” Food borne Pathogenic Microorganisms and Natural Toxins Handbook.

51 References Rollins, David M. "Corynebacterium Summary." BSCI 424 — Pathogenic Microbiology. Aug Dept. of Cell Bio. & Genetics, UMD. 2 May Rollins, David M. "Corynebacterium Summary." BSCI 424 — Pathogenic Microbiology. Aug Dept. of Cell Bio. & Molecular Genetics, UMD. 2 May Madigan, Michael T., and John M. Martinko. Brock Biology of Microorganisms. 11th ed. London: Pearson Prentice Hall, Madigan, Michael T., and John M. Martinko. Brock Biology of Microorganisms. 11th ed. London: Pearson Prentice Hall, Sneath, Peter H., James T. Staley, and Stanley T. Williams, eds. Bergey's Manual of Systematic Bacteriology. Vol. 2. Baltimore: William and Wilkins, Sneath, Peter H., James T. Staley, and Stanley T. Williams, eds. Bergey's Manual of Systematic Bacteriology. Vol. 2. Baltimore: William and Wilkins,


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