Escherichia coli

1. Escherichia coli
https://www.euro.who.int/en/health-topics/disease-prevention/food-
safety/news/news/2011/07/outbreaks-of-e.-coli-o104h4-infection-update-30
https://www.cdc.gov/ecoli/general/index.html
https://epi.dph.ncdhhs.gov/cd/diseases/ecoli.html

2. General description
• Gram negative, rod shaped, flagellated, has
pili, catalase positive …..
• Heterotroph, facultative anaerobic.
• E. coli commonly found in the gut of humans
and warm-blooded animals. The reservoir of
this pathogen is mainly cattle.
• Most strains are harmless but some produce
endotoxins e.g. STEC (O157:H7). Luckily, it is
heat-sensitive.

4. Epidemology
• In US alone, approximately 265K case/year, and about
100 deaths.
• On July 2011, E. coli -Outbreak O104:H4 infections
have spread in 16 countries, and had reported 4075
cases and 50 deaths. Also, 908 persons had suffered
from kidney damage due to HUS.
• Transmitted through fecal contaminated food and
water, raw meat, …. Dealing with infected people and
animals, too.
• E. coli is usually associated with traveler's diarrhea,
gastroenteritis and UTI.

6. Clinical manifestation
• E. coli infections causes gastroenteritis which
could be divided mainly to ETEC and EHEC.
• Symptoms appear after 3-4 days of infection
like abdominal cramps and diarrhea. Fever
and vomiting may also occur.
• E. coli infection may lead to a life-threatening
disease, such as hemolytic anemia, HUS,
kidney damage.

8. Prevention and treatment
• To protect ourselves we have to start within
industry, household, producers of vegetables and
cattle-keepers.
• E. coli infections are self-limiting infections and
patients recover within 10 days.
• Treatment focuses on replacement of fluid and
electrolytes lost from vomiting and diarrhea.
• Antibiotics and anti- diarrhea drugs like Nalidixic
acid & loperamide, respectively, are not
recommended for healthy people.

10. Staphylococcus epidermidis
https://www.researchgate.net/figure/Pr
evalence-of-bacterial-strains-Strata-by-
Staphylococcus-aureus-epidermidis-
other_fig1_255954071

11. General description
• Gram positive, cocci shaped, non motile, non-
spore forming and encapsulated…..
• Heterotroph, facultative anaerobic.
• Catalase positive, B-hemolotic & requires a
sensitive media to be cultured.
• Usually S. epidermidis in normal skin flora is
nonpathogenic. But in abnormal lesions, it
becomes pathogenic, like in acne vulgaris.

13. Epidemiology
• S. epidermidis infections are hospital occurred
infections.
• S. epidermidis is a major cause of cardiac
implantable electronic devices (CIED)
inflammation.
• In a recent study, a total of 508 IV catheters (IVCs)
from 331 patients were submitted for culture
from May to October 2013. The study
identified S. epidermidis as the causal agent in
42.1% of the (CIED) cases.

15. Clinical manifestation
• S. epidermidis is universally found to cause acne
vulgaris in addition to Propionibacterium.
• S. epidermidis enters the sebaceous gland by
producing lipolytic enzymes and changes the
sebum to a thick form.
• Symptoms include redness, warmth, and pain.
The person may develop a fever & swelling in that
area.
• Moreover, it has transferrin-binding protein that
binds to transferrin and remove its iron.

17. Prevention and treatment
• To protect ourselves we have to wash our
hands thoroughly with soap and water,
Keep cuts clean and covered, and not to share
personal items….
• Unfortunately, S. epidermidis has gained
resistance to Methicillin. However, we can still
treat it topically with vancomycin to which
rifampin could be added.

19. Hepatitis B virus
https://www.who.int/news-room/fact-
sheets/detail/hepatitis-b
https://www.who.int/immunization/monitoring_surveillanc
e/burden/vpd/surveillance_type/passive/hepb3_1985_201
9_big.gif?ua=1

20. General description
• Hepatitis B virus (HBV) is a member of the
Hepadnaviridae family. It is a ssDNA virus,
enveloped & has different antigens (HBs, HBc
& HBe).
• Enter by endocytosis by binding to heparin
sulfate proteoglycan. Leave by fusing to
hepatic cells without damaging it.

22. Epidemiology
• Hepatitis B prevalence is highest in the Western
Pacific Region and the African Region.
• WHO estimates that in 2015, 257 million people
were infected, and it has resulted in 887.000
deaths.
• Infection in adulthood leads to chronic hepatitis
in less than 5% of cases, whereas infection in
infancy and early childhood leads to chronic
hepatitis in about 95% of cases- with a chance of
80–90% of infection during the first year of life.

24. Clinical manifestation
• The hepatitis B virus can survive on surfaces for
at least 7 days. The incubation period of the
hepatitis B virus is 75 days on average.
• The virus is most commonly transmitted from
mother to child, as well as contacting with other’s
body fluids.
• The symptoms appear due to immune’s response.
However, they include jaundice, dark urine,
vomiting and abdominal pain…..
• Chronic Hepatitis B may develop into cirrhosis or
liver cancer.

26. Prevention and treatment
• To protect ourselves we have to wash our hands
with soap and water, Keep cuts clean and
covered, and not to share personal items…
• WHO recommends the hepatitis B vaccination
espatially for infants, healthcare professionals, ….
• There is no specific treatment for Acute Hepatitis
B. However, WHO recommends to replace fluids
that had lost from vomiting and diarrhea.
• Treatment for Chronic hepatitis B slows the
progression of the disease. However, oral antiviral
agents -tenofovir or entecavir could help.