Microbiology BSN first year

1. Microbiology in Everyday
Life
(Food, Water & Airborne Diseases)
Muhammad Iqbal
Lecturer
KMU

2. Food Borne Diseases
 Diseases caused by microorganisms
through food
 Microorganisms can cause
Food spoilage
Diseases

3. Foodborne Diseases
Usually called “Food Poisoning”  caused by
eating the food contaminated with toxin.
 Two main types:
1. Toxin is produced in the food (exotoxin) causes
the disease called food poisoning
2. Food, being a mechanical carrier, carries
pathogens and cause disease on ingestion.

4. Food borne Pathogens
Gram Negative Bacteria
 Salmonella (Typhimurium and Enteritidis)
 Shigella
 Vibrio cholerae

5. Other Organisms
 Amoeba
Giardia lamblia
Entamoeba histolytica
Cryptosporidium
 Fungi 100s of poisonous mushrooms
Aspergillus  aflatoxins
Claviceps hallucinogens
 Algae certain marine algae produce
neurotoxins contaminate shell fish

6. Intoxication vs. Infection
Intoxication
 Manifested much
more quickly
 Toxin is already
present to cause
harm
 Toxin is the direct
cause of disease
Infection
 Pathogen has to be
ingested
 After a period of
incubation ,pathogen
establishes itself,
usually in the intestine
 Causes infection

7. Transmission of Foodborne Diseases
 4 main ways 4Fs
Food
Feces
Fingers
Flies
 Food is the immediate source of the
pathogen/toxin
 May be acquired by close contact with an
infected person or a carrier
 Involves the fecal-oral route

8. General Measures of Prevention
 Clean & store produce properly
 Prepare food properly cooking adequately
 Employ general sanitary procedures while
handling food
 Eat cooked food promptly
 Restrict carriers from food preparation
 Protect food from insects, rodents
 Use pure water

9. Prevention cont…
Based on the route of transmission two
main ways of prevention
1. Reduce the possibility of food handlers
contaminating food
( education in general hygiene)
2. Keep cold foods cold, hot foods hot
( serve foods when prepared or keep
refrigerated, do not allow foods to sit at
room temperature)

10. Food Poisoning

11. Staphylococcal Food Poisoning
 Staphylococcus aureus  gm +ve
 Humans harbor these organisms, present in
boils, skin lesions
 Food poisoning is caused when staph is
transferred from person to food
Could come from an open boil, lesions sneeze, etc

12. Staphylococcal Food Poisoning
 Exotoxins are heat stable proteins known as
enterotoxins (affecting the intestines)
 Inhibit water absorption from the intestine &
induce diarrhea & vomiting
 Damages the intestinal lining colitis
 Nausea, vomiting, abdominal cramps, diarrhea
Onset 1-6 hours after eating the contaminated
food

13. Clostridium botulinum & Botulism
 C. botulinum Gm(+) , endospore
forming organism, anaerobic
 Present in soil, ponds and lakes

14. Botulism
 Infrequent, but fatal
 Caused by exotoxins produced by
C. botulinum most deadly
biological toxin neurotoxin and
affects the CNS

15. Prevention
 Endospores present may not be
removed by washing
 Proper canning
 After canning avoid bulging
can/jar

16. Clostridium perfringes
 Anaerobic spore former
 Present in soil & intestines of humans and
animals hence also in sewage
 Typical illness diarrhea, abdominal cramps,
nausea and vomiting
 Sickness lasts a day, incubation period is
usually 6—24 hours
 Prevention: refrigerate food and cook
adequately