bacterial screenshot

1. BACTERIA
SCREENSHOT
PRESENTATION
Staphylococcus aureus
Escherichia coli
Neisseria meningiditis
K.Napper & S. Schemery
College of Southern Maryland
This presentation was prepared for
MLT-2010, taught by Professor T. Gill
Figure 1 Staphylococcus aureus. (2014, June 19). Wikipedia
Figure 2 E.coli (www.visualphotos.com/image/1x3746017.).
Figure 3 Neisseria meningitidis. (n.d.). Bioquell

2. STAPHYLOCOCCUS AUREUS
Figure 5 Staphylococcus aureus (Pictures.life.ku.dk, 2014)Figure 4 Staphylococcus aureus. (2014, June 19). Wikipedia

3. STAPHYLOCOCCUS AUREUS
Figure 6 Staphylococcus aureus Bacteriainphotos

4. STAPHYLOCOCCUS AUREUS
Cellular Morphology
• Gram positive cocci in grape like clusters.
Colony Morphology
• Grows well on blood agar and abundant
growth in 18-24 hrs
• Large (6-8 mm) smooth, entire, slightly
raised, translucent, and pigmented colonies
• Off-white, gray, cream-yellow, yellow,
yellow-orange, or orange pigment
• Colonies surrounded by multiple zones of
hemolysis, resembling targets
• On MSA plates colonies will have a yellow
pigment and the pink medium will turn
yellow
Figure 7 Staphylococcus aureus(Hogan,2011)
Figure 9 Physiological tests (Web.cn.edu, 2014)
Figure 8 Staphylococcus aureus (Pictures.life.ku.dk, 2014)

5. STAPHYLOCOCCUS AUREUS
Distinguishing Media
• Blood Agar – for hemolysis
detection
• Mannitol Salt Agar (MSA)-for
mannitol fermentation
Differential and
Susceptibility testing
• Catalase positive
• Coagulase positive
• Commercial latex agglutination
testing
• Most strains susceptible to penicillin
but some are resistant
• Methicillin-resistant MRSA and
Vancomycin-resistant strains VRSA

6. STAPHYLOCOCCUS AUREUS
Indigenous locations
• Often found in low numbers as
indigenous microflora of the skin.
• 20% -30% of the population are
“staph carriers” – nasal passages
are colonized with S. aureus. As
long as the S. aureus is localized to
the nasal passages of the carrier it
poses no threat, but the bacteria
can be transmitted to others.
Infections caused by
bacteria
• Skin and soft tissue-Furnicle, Cabuncles,
Wound infections ( surgical/ traumatic),
Cellulitis, Impetigo
• Musculoskeltal- Ostemyelitis, Arthritis
• Cardiovascular- Endocarditis
• Genitourinary Tract- Renal carbuncle,
Lower urinary tract infection
• Other infections cause by toxins-
Toxic shock syndrome (TSS), Scalded skin
syndrome, Food poisoning (gastroenteritis)

7. ESCHERICHIA COLI
Figure 11 E. coli on MAC(Bacteriainphotos.com, 2014)Figure 10 E coli (www.visualphotos.com/image/1x3746017).

8. ESCHERICHIA COLI
Figure 12 Escherichia coli Bacteriainphotos

9. ESCHERICHIA COLI
Cellular morphology
• Gram negative bacilli motile by
peritrichous flagella
Colony Morphology
• On blood agar colonies are smooth,
dull gray, and 2-3 mm in diameter
• On MAC colonies are lactose-
positive colonies producing pink to
red, flat, dry, and 2-3 mm in
diameter. The colonies are usually
surrounded by a darker pink area of
precipitated bile salts
• On HE and XLD agar colonies have
a yellow pigment.
• Foul odor
Figure 13 E. coli(News, 2014) Figure 14 E. coli on TSA (Catalog.hardydiagnostics.com, 2014
Figure 15 E. coli on MAC(Bacteriainphotos.com, 2014)

10. ESCHERICHIA COLI
Distinguishing Media
• Blood agar – for hemolysis
detection
• MAC – lactose fermentation
detection
• HE
• XLD
Differential and
Susceptibility testing
• A/A reaction on TSI
and KIA slants with
or without gas
• Indole positive
• MR positive
• Voges-Proskauer
negative
• Citrate negative
• Oxidase negative
• Nitrate positive
• PYR negative
• MUG positive
IF SUSCEPTIBLE:
Cephalosporins I, II, III
Aminoglycosides
Nitrofurantoin
Trimethoprim-
sulfamethoxazole
Doxycycline

11. ESCHERICHIA COLI
Indigenous locations
• Commonly found in the indigenous
gastrointestinal flora of humans and
animals
Infections caused by
bacteria
• The strains and serotypes of E. coli
found in the GI tracts of humans
and animals are opportunistic
pathogens and can be problematic
when entering other sites than the
GI tract (bladder, bloodstream,
wounds)
• Most common cause of UTIs and
common cause of septicemia and
nosocomial infections
• Enterovirulent E. coli or
diarrheagenic E. coli serotypes
cause GI disease when they are
ingested by humans.

12. NEISSERIA MENINGITIDIS
Figure 17 N. meningiditis on Choc (Cdc.gov, 2014
Figure 16 Neisseria meningitidis. (n.d.). Bioquell

13. NEISSERIA MENINGITIDIS
Figure 18 Neisseria meningitigis Bacteriainphotos

14. NEISSERIA MENINGITIDIS
Cellular morphology
• Encapsulated gram negative diplococcus • Grows best at 35-37C in moist 5%-7%
CO2 environment
• On Blood agar, Chocolate agar, or
Thayer-Martin medium colonies are
gray, low, convex, and glistening,
with a smooth, moist entire edge.
• Heavily encapsulated strains may
be mucoid.
• N. meningiditis colonies are about 1
mm larger than N. gonorrhoeae
after 18-24 hrs. of incubation.
• Older colonies become gummy
due to autolysis and release of
cellular DNA.
Colony morphology
Figure 20 N. meningiditis(Textbookofbacteriology.net,
2014)
Figure 19 N. meningiditis on Choc (Cdc.gov, 2014
Figure 21 N. menigniditis on BA(Cdc.gov, 2014)

15. NEISSERIA MENINGITIDIS
Distinguishing Media
• Will grow on Blood agar incubated
in non-CO2 incubator where as N.
gonorrhoeae will not.
• Thayer- Martin
Differential and
Susceptibility testing
• Carbohydrate utilization or
chromogenic enzyme substrate test
• Will acidify media containing
glucose and maltose
• Oxidase positive
• IF SUSCEPTIBLE:
penicillin G
ampicillin

16. NEISSERIA MENINGITIDIS
Indigenous locations
• Strict human pathogen
• Colonizes the nasopharyngeal
mucosa of some individuals; N.
meningiditis carriers
• May also colonizes the genital tract
and conjunctiva
Infections causes by
bacteria
• N. meningiditis may be transmitted
from person to person by transfer of
respiratory secretions or aerosolized
droplets
• Menigococcemia (N. meningiditis in
blood stream)
• Petechiae
• Meningococcus meningitis
• Rare types of infections- genital tract
infection, proctitis, and conjunctivitis

17. REFERENCES• Bacteriainphotos.com (2014). Escherichia coli colonies on macconkey agar, e.coli lactose positive colonies. [online] Retrieved from:
http://www.bacteriainphotos.com/Escherichia%20coli%20on%20MacConkey%20agar.html [Accessed: 22 Jun 2014].
• Catalog.hardydiagnostics.com (2014). Tryptic soy agar (tsa). [online] Retrieved from:
https://catalog.hardydiagnostics.com/cp_prod/Content/hugo/TrypticSoyAgar.htm [Accessed: 22 Jun 2014].
• Cdc.gov (2014). Cdc - meningitis - lab manual - identification and characterization of neisseria meningitidis - chapter 7. [online] Retrieved from:
http://www.cdc.gov/meningitis/lab-manual/chpt07-id-characterization-nm.html [Accessed: 22 Jun 2014].
• E. Coli. (Color Enhanced Shadow cast Transmission Electron Micrograph (TEM) Of The Bacteria Escherichia Coli. E. Coli Is Found In The Human Intestinal Tract And Is Normally Non
pathological. Certain Strains Can Cause Sev | Stock Photos | Royalty Free | Royalty Free Photos. (n.d.). Retrieved March 17, 2015, from
http://www.visualphotos.com/image/1x3746017/e-coli-color-enhanced-shadow-cast-transmission-electron-micrograph-tem-of-the-bacteria-escherichia-coli-e-coli-is-found-in-
the-human-intestinal-tract-and-is-normally-non-pathological-certain-strains-can-cause-sev
• Engelkirk, P. & Duben-Englekirk, J. (2008). Laboratory diagnostics of infectious diseases: essentials of diagnostic microbiolgy. Batlimore: Lippincott Williams & Wilkins,
a Wolters Kluer business.
• Escherichia coli. Bacteriainphotos, Retrived June 25, 2014, from http://www.bacteriainphotos.com/bacteria%20photo%20gallery.html#ecoli
• Hogan, G. (2011). Staphylococcus aureus. [online] Retrieved from: http://www.microbeworld.org/index.php?option=com_jlibrary&view=article&id=7611
[Accessed: 22 Jun 2014].
• Neisseria meningitidis. (n.d.). Bioquell. Retrieved June 22, 2014, from http://www.bioquell.com/technology/microbiology/neisseria-meningitidis
• Neisseria Meningitidis. Bacteriainphotos. Retrieved June 25, 2014, from http://www.bacteriainphotos.com/Meningococcus.html
• News, B. (2014). Local food distributor might be behind e. coli outbreak at trader joe's. [online] Retrieved from: http://sfappeal.com/2013/11/local-food-distributor-
might-be-behind-e-coli-outbreak-at-trader-joes/ [Accessed: 22 Jun 2014].
• Pictures.life.ku.dk (2014). Staphylococcus aureus. [online] Retrieved from:
http://pictures.life.ku.dk/atlas/microatlas/food/bacteria/Staphylococcus_aureus/pop1.html [Accessed: 22 Jun 2014].
• Textbookofbacteriology.net (2014). The normal bacterial flora of humans. [online] Retrieved from: http://textbookofbacteriology.net/normalflora.html [Accessed:
22 Jun 2014].
• Staphylococcus aureus. Bacteriainphotos . Retrieved June 25, 2014, from http://www.bacteriainphotos.com/beta_hemolysis_on_agar.html
• Staphylococcus aureus. (2014, June 19). Wikipedia. Retrieved June 22, 2014, from http://en.wikipedia.org/wiki/Staphylococcus_aureus
• Web.cn.edu (2014). Physiological tests. [online] Retrieved from: http://web.cn.edu/stkarr/physiolo.htm [Accessed: 22 Jun 2014].