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Pathology

The study of a disease. it deals with etiology,pathogenesis and effect of disease on body

Etiology

Study of caude of disease

pathogenesis

development of disease

Infection

colonization of the body by pathogens( a pathogen invading your body)
An infection is not always caused by a disease

disease

abnormal state in which the body is not functioning normally. It is what comes after an infection

transient microbiota

may be present for days, weeks, or months
(visitor they come and go)

Normal microbiota

permanently colonize the host

Symbiosis

relationship between normal microbiota and the host

Commensalism

one organism benefits, and the other is unaffected

Mutualism

both organism benefit ex E. coli

parasitism

one organism benefits at the expense of the other

Microbial Antagonism

competition between microbes

Normal Microbiota protect the host by

occupying niches that pathogens might occupy
producing acids producing bacteriocins

Probiotics:

live microbes applied to or ingested into the body, intended to exert a beneficial effect ex lactos bacillus

Koch postulates

The same pathogen must be present in every case of the disease
The pathogen must be isolated from the diseases host and grown in pure culture
The pathogen from the pure culture must cause the disease when it is inoculated into a healthy, susceptible lab animal
The pathogen must be isolated from the inoculated animal and must be shown to be the original animal

Endemic disease

...

Symptom

A change in body function that is felt by a patient as a result of disease

Sign

A change in a body that can be measured or observed as a result of disease

Syndrome

A specific group of signs and symptoms that accompany a disease

Communicable disease

A disease that is spread from one host to another

Contagious disease

A disease that is easily spread from one host to another

Noncommunicable diseas e:

A disease that is not transmitted from one host to another

Incidence

Fraction of a population that contracts a disease during a specific time

Prevalence

Fraction of a population having a specific disease at a given time

Sporadic disease

Disease that occurs occasionally in a population

Endemic disease

Disease constantly present in a population

Epidemic disease

Disease acquired by many hosts in a given area in a short time

Pandemic disease

Worldwide epidemic

Herd immunity

Immunity in most of a population

Acute disease

Symptoms develop rapidly

Chronic disease

Disease develops slowly

Subacute disease

Symptoms between acute and chronic

Latent disease

Disease with a period of no symptoms when the causative agent is inactive

Local infection

Pathogens are limited to a small area of the body

Systemic infection

An infection throughout the body

Focal infection

Systemic infection that began as a local infection

Sepsis

Toxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infection

Bacteremia

Bacteria in the blood

Septicemia

Growth of bacteria in the blood

Toxemia

Toxins in the blood

Viremia

Viruses in the blood

Primary infection

Acute infection that causes the initial illness

Secondary infection

Opportunistic infection after a primary (predisposing) infection

Subclinical disease

No noticeable signs or symptoms (inapparent infection)

Make the body more susceptible to disease

Short urethra in females
Inherited traits, such as the sickle cell gene
Climate and weather
Fatigue
Age
Lifestyle
Chemotherapy

Contact Direct

Requires close association between infected and susceptible host

Indirect

Spread by fomites

Droplet

Transmission via airborne droplets

Vectors

Arthropods, especially fleas, ticks, and mosquitoes

Vectors Transmit disease by 2 general methods

Mechanical transmission: Arthropod carries pathogen on feet
Biological transmission: Pathogen reproduces in vector

Nosocomial Infections

Are acquired as a result of a hospital stay
Affect 5-15% of all hospital patients

Emerging Infectious Diseases

Diseases that are new, increasing in incidence, or showing a potential to increase in the near future

Emerging Infectious Diseases Contributing factors

Genetic recombination
E. coli O157, avian influenza (H5N1)
Evolution of new strains
V. cholerae O139
Inappropriate use of antibiotics and pesticides
Antibiotic-resistant strains
Changes in weather patterns
Hantavirus
Modern transportation
West Nile virus
Ecological disaster, war, and expanding human settlement
Coccidioidomycosis
Animal control measures
Lyme disease
Public health failure
Diphtheria

Epidemiology

The study of where and when diseases occur

Morbidity

Incidence of a specific notifiable disease

Mortality

Deaths from notifiable diseases

Morbidity rate

Number of people affected in relation to the total population in a given time period

Mortality rate

Number of deaths from a disease in relation to the population in a given time

Which one of the following does NOT contribute to the incidence of nosocomial infections?
A) Formation of biofilms
B) Lapse in aseptic techniques
C) Gram-negative cell walls
D) Lack of handwashing
E) Lack of insect control

c

Which of the following is NOT a communicable diseases?
A) Malaria
B) AIDS
C) Tuberculosis
D) Tetanus
E) Typhoid fever

d

Koch's postulates don't apply to all diseases because
A) Some microorganisms can't be cultured in laboratory media.
B) Some microorganisms don't cause the same disease in laboratory animals.
C) Some microorganisms cause different symptoms under different conditions.
D) Some microorganisms can't be observed.
E) Not all diseases are caused by microorganisms

e

The graph in Figure 14.3 shows the incidence of polio in the United States. The period between 1945 and 1955indicates
A) An endemic level.
B) An epidemic level.
C) A sporadic infection.
D) A communicable disease.
E) A pandemic

b

Which of these infections can cause septicemia?
A) Bacteremia
B) Focal infection
C) Local infection
D) Septicemia
E) Systemic infection

b

A cold transmitted by a facial tissue is an example of
A) Direct contact.
B) Droplet transmission.
C) Fomite.
D) Vector.
E) Vehicle transmissio

c

Which of the following pairs is mismatched?
A) Malaria - vector
B) Salmonellosis - vehicle transmission
C) Syphilis - direct contact
D) Influenza - droplet infection
E) All of these are correctly matched

e

8. A nosocomial infection is
A) Always present but is inapparent at the time of hospitalization.
B) Acquired during the course of hospitalization.
C) Always caused by medical personnel.
D) Only a result of surgery.
E) Always caused by pathogenic bacteria.

b

9. Which of the following can contribute to postoperative infections?
A) Using syringes more than once
B) Normal microbiota on the operating room staff
C) Errors in aseptic technique
D) Antibiotic resistance
E) All of these

e

Pseudomonas bacteria colonized the bile duct of a patient following his liver transplant surgery. This is an example of a
A) Communicable disease.
B) Latent infection.
C) Nosocomial infection.
D) Sporadic disease.
E) None of these.

c

The science that deals with when diseases occur and how they are transmitted is called
A) Ecology.
B) Epidemiology.
C) Communicable disease.
D) Morbidity and mortality.
E) Public health.

b

12. Mechanical transmission differs from biological transmission in that mechanical transmission
A) Doesn't require an arthropod.
B) Involves fomites.
C) Doesn't involve specific diseases.
D) Requires direct contact.
E) Doesn't work with noncommunicable diseases

c

Emergence of infectious diseases can be due to all of the following EXCEPT
A) Antibiotic resistance.
B) Climatic changes.
C) Digging up soil.
D) Microbes trying to cause disease.
E) Travel

d

During a 6-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous 3 years.


In Situation 14.1, the etiologic agent of the disease is
A) Sheep.
B) Soil.
C) Coxiella burnetii.
D) Pneumonia.
E) Wind.

c

One effect of washing regularly with antibacterial agents is the removal of normal microbiota. This can result in
A) Body odor.
B) Fewer diseases.
C) Increased susceptibility to disease.
D) Normal microbiota returning immediately.
E) No bacterial growth because washing removes their food source.

c

A sexually transmitted disease is an example of
A) Direct contact.
B) Droplet transmission.
C) Fomite.
D) Vector.
E) Vehicle transmission

a

Which of the following diseases is NOT spread by droplet infection?
A) Botulism
B) Tuberculosis
C) Measles
D) Common cold
E) Diphtheria

a

A needlestick is an example of
A) Direct contact.
B) Droplet transmission.
C) Fomite.
D) Vector.
E) Vehicle transmission

c

Symptoms of disease differ from signs of disease in that symptoms
A) Are changes felt by the patient.
B) Are changes observed by the physician.
C) Are specific for a particular disease.
D) Always occur as part of a syndrome.
E) None of these.

a

Influenza transmitted by an unprotected sneeze is an example of
A) Direct contact.
B) Droplet transmission.
C) Fomite.
D) Vector.
E) Vehicle transmission.

b

A commensal bacterium
A)

Does not receive any benefit from its host.
B)

Is beneficial to its host.
C)

May be an opportunistic pathogen.
D)

Does not infect its host.
E)

B and D only.

E

2)

Which of the following statements is true?
A)

Symbiosis refers to different organisms living together.
B)

Members of a symbiotic relationship cannot live without each other.
C)

A parasite is not in symbiosis with its host.
D)

Symbiosis refers to different organisms living together and benefiting from each other.
E)

At least one member must benefit in a symbiotic relationship.

...A

3)

A nosocomial infection is
A)

Always present but inapparent at the time of hospitalization.
B)

Acquired during the course of hospitalization.
C)

Always caused by medical personnel.
D)

Only a result of surgery.
E)

Always caused by pathogenic bacteria.

...B

4)

The major significance of Koch's work was that
A)

Microorganisms are present in a diseased animal.
B)

Diseases can be transmitted from one animal to another.
C)

Microorganisms can be cultured.
D)

Microorganisms cause disease.
E)

Microorganisms are the result of disease.

...D

5)

Koch's postulates don't apply to all diseases because
A)

Some microorganisms can't be cultured in laboratory media.
B)

Some microorganisms don't cause the same disease in laboratory animals.
C)

Some microorganisms cause different symptoms under different conditions.
D)

Some microorganisms can't be observed.
E)

All diseases aren't caused by microorganisms.

...E

6)

Which of the following diseases is not spread by droplet infection?
A)

Botulism
B)

Tuberculosis
C)

Measles
D)

Common cold
E)

Diphtheria

...A

7)

Mechanical transmission differs from biological transmission in that mechanical transmission
A)

Doesn't require an arthropod.
B)

Involves fomites.
C)

Doesn't involve specific diseases.
D)

Requires direct contact.
E)

Doesn't work with noncommunicable diseases.

...C

8)

Which of the following definitions is incorrect?
A)

Endemic  a disease that is constantly present in a population
B)

Epidemic  fraction of the population having a disease at a specified time
C)

Pandemic  a disease that affects a large number of people in the world in a short time
D)

Sporadic  a disease that affects a population occasionally
E)

None of the above

...B

9)

Which of these infections can cause septicemia?
A)

Bacteremia
B)

Focal infection
C)

Local infection
D)

Septicemia
E)

Systemic infection

C

10)

Which type of infection can be caused by septicemia?
A)

Bacteremia
B)

Focal infection
C)

Local infection
D)

Septicemia
E)

Systemic infection

...E

11)

Koch observed Bacillus anthracis multiplying in the blood of cattle. What is this condition called?
A)

Bacteremia
B)

Focal infection
C)

Local infection
D)

Septicemia
E)

Systemic infection

...D

12)

Nosocomial infections are most often caused by
A)

Escherichia coli.
B)

Staphylococcus aureus.
C)

Enterococcus.
D)

Pseudomonas.
E)

Klebsiella.

...C

13)

Transient microbiota differ from normal microbiota because transient microbiota
A)

Cause diseases.
B)

Are found in a certain location on the host.
C)

Are acquired by direct contact.
D)

Are present for a relatively short time.
E)

None of the above.

...D

14)

Which of the following statements about nosocomial infections is not true?
A)

They occur in compromised patients.
B)

They are caused by opportunists.
C)

They are caused by drug-resistant bacteria.
D)

They are caused by normal microbiota.
E)

None of the above.

...E

15)

One effect of washing regularly with antibacterial agents is the removal of normal microbiota. This can result in
A)

Body odor.
B)

Fewer diseases.
C)

Increased susceptibility to disease.
D)

Normal microbiota returning immediately.
E)

No bacterial growth because washing removes their food source.

...C

16)

Which of the following is not a reservoir of infection?
A)

A sick person
B)

A healthy person
C)

A sick animal
D)

A hospital
E)

None of the above

...E

17)

All of the following are communicable diseases except
A)

Malaria.
B)

AIDS.
C)

Tuberculosis.
D)

Tetanus.
E)

Typhoid fever.

...D

18)

Which of the following is a fomite?
A)

Water
B)

Droplets from a sneeze
C)

Pus
D)

Insects
E)

A hypodermic needle

...E

19)

All of the following statements about biological transmission are true except
A)

The pathogen reproduces in the vector.
B)

The pathogen may enter the host in the vector's feces.
C)

Houseflies are an important vector.
D)

The pathogen may be injected by the bite of the vector.
E)

The pathogen may require the vector as a host.

...C

20)

Which of the following definitions is incorrect?
A)

Acute  a short-lasting primary infection
B)

Inapparent  infection characteristic of a carrier state
C)

Chronic  a disease that develops slowly and lasts for months
D)

Primary infection  an initial illness
E)

Secondary infection  a long-lasting illness

...E

21)

Symptoms of disease differ from signs of disease in that symptoms
A)

Are changes felt by the patient.
B)

Are changes observed by the physician.
C)

Are specific for a particular disease.
D)

Always occur as part of a syndrome.
E)

None of the above.

...A

22)

The science that deals with when diseases occur and how they are transmitted is called
A)

Ecology.
B)

Epidemiology.
C)

Communicable disease.
D)

Morbidity and mortality.
E)

Public health.

...B

Figure 14.1





24)

Emergence of infectious diseases can be due to all of the following except
A) Antibiotic resistance.
B)

Climatic changes.
C)

Digging up soil.
D)

Microbes trying to cause disease.
E)

Travel.

...D

25)

Which of the following pairs is mismatched?
A)

Malaria  vector
B)

Salmonellosis  vehicle transmission
C)

Syphilis  direct contact
D)

Influenza  droplet infection
E)

None of the above

...E

26)

All of the following can contribute to postoperative infections except
A)

Using syringes more than once.
B)

Normal microbiota on the operating room staff.
C)

Errors in aseptic technique.
D)

Antibiotic resistance.
E)

None of the above.

...E

Figure 14.2




28)

A cold transmitted by a facial tissue is an example of
A)

Direct contact
B)

Droplet transmission
C)

Fomite
D)

Vector
E)

Vehicle transmission

...C

29)

Influenza transmitted by an unprotected sneeze is an example of
A)

Direct contact.
B)

Droplet transmission.
C)

Fomite.
D)

Vector.
E)

Vehicle transmission.

...B

30)

A sexually transmitted disease is an example of
A)

Direct contact.
B)

Droplet transmission.
C)

Fomite.
D)

Vector.
E)

Vehicle transmission.

...A

31)

Gastroenteritis acquired from roast beef is an example of
A)

Direct contact.
B)

Droplet transmission.
C)

Fomite.
D)

Vector.
E)

Vehicle transmission.

...E

32)

A needlestick is an example of
A)

Direct contact.
B)

Droplet transmission.
C)

Fomite.
D)

Vector.
E)

Vehicle transmission.

...C

33)

Legionellosis transmitted by a grocery store mist machine is an example of
A)

Direct contact.
B)

Droplet transmission.
C)

Fomite.
D)

Vector.
E)

Vehicle transmission.

...E

34)

Plague transmitted by a flea is an example of
A)

Direct contact.
B)

Droplet transmission.
C)

Fomite.
D)

Vector.
E)

Vehicle transmission.

...D

35)

The most likely mode of transmission of pneumonic plague between humans is
A)

Direct contact.
B)

Droplet transmission.
C)

Fomite.
D)

Vector.
E)

Vehicle transmission.

...B

39)

Which one of the following is not an example of microbial antagonism?
A)

Acid production by bacteria
B)

Bacteriocin production
C)

Bacteria occupying host receptors
D)

Bacteria causing disease
E)

None of the above

...D

40)

The yeast Candida albicans does not normally cause disease because of
A)

Symbiotic bacteria.
B)

Antagonistic bacteria.
C)

Parasitic bacteria.
D)

Commensal bacteria.
E)

None of the above.

...B

41)

Haemophilus bacteria require heme protein produced by Staphylococcus bacteria. This is an example of
A)

Antagonism.
B)

Commensalism.
C)

Parasitism.
D)

Synergism.
E)

None of the above.

...B

42)

Which one of the following is not a zoonosis?
A)

Cat-scratch disease
B)

Hantavirus pulmonary syndrome
C)

Rabies
D)

Tapeworm
E)

None of the above

...

43)

Pseudomonas bacteria colonized the bile duct of a patient following his liver transplant surgery. This is an example of a
A)

Communicable disease.
B)

Latent infection.
C)

Nosocomial infection.
D)

Sporadic disease.
E)

None of the above.

...C

45)

Which one of the following does not contribute to the incidence of nosocomial infections?
A)

Formation of biofilms.
B)

Lapse in aseptic techniques.
C)

Gram-negative cell walls.
D)

Lack of hand-washing.
E)

Lack of insect control.

...C

Chemotherapy

The use of drugs to treat a disease

Antimicrobial drugs

Interfere with the growth of microbes within a host

Antibiotic

A substance produced by a microbe that, in small amounts, inhibits another microbe

Selective toxicity

A drug that kills harmful microbes without damaging the host

Bactericidal

Kill microbes directly

Bacteriostatic

Prevent microbes from growing

penicillin mode of action

inhibitors of cell wall synthesis

penicillim Ampicillin

Broad spectrum

penicillin Amoxicillin

broad spectrum,combined with inhibiyor of prnicillinase

Cephalosporin mode of action

inhibitors of cell wall synthesis

cephalosporin

First-generation: Narrow spectrum, gram-positive
Second-generation: Extended spectrum includes gram-negative
Third-generation: Includes pseudomonads; injected
Fourth-generation: Oral

bacitracin mode of action

inhibitors of cell wall synthesis

bacitracin

Topical application
Against gram-positives

Vamcomycin mode of action

inhibitor of cell wal synthesis

vamcomycin

Glycopeptide
Narrow spectrum
Important "last line" against antibiotic-resistant S. aureus (MRSA)

Antimycobacterial antibiotics

moed of action inhibitor of cell wall synthesis
Isoniazid (INH)
Inhibits mycolic acid synthesis
Ethambutol
Inhibits incorporation of mycolic acid

Chloramphenicol mode of action

inhibitors of protein synthesis
Broad spectrum
Binds 50S subunit; inhibits peptide bond formation
Disadvantage: Suppression of bone marrow activity

Aminoglycosides

Mode of action: inhibitors of protein synthesis
Streptomycin, neomycin, gentamycin
Useful against pseudomonads
Broad spectrum
Changes shape of 30S subunit
Disadvantage: Auditory nerve damage and damage to kidney.

Tetracyclines

Inhibitors of protein synthesis
Broad spectrum
Interferes with tRNA attachment
Works against intracellular parasites
Suppress normal intestinal microbiota and often cause superinfections.
Not advised for children and pregnant women

Macrolides

Inhibitors of protein synthesis
Ex Erythromycin(alternative to penicillin)
Only Gram-positives
Binds 50S; prevents translocation

Polymixin B

Injury to the plasma membrane
Prevents biosynthesis of fatty acids for the membrane
Ex: Polymyxin B
Topical
Combined with bacitracin and neomycin in over-the-counter preparation
gram negative bacteria including pseudomonas spp

Rifamycin

inhibitors of nucleic acid synthesis
Inhibits mRNA synthesis
Antituberculosis
Penetrate tissues and reach therapeutic levels Iin cerebrospinal fluids and abscesses.

Quinolones and fluoroquinolones

Inhibitors of nucleic acid synthesis
Nalidixic acid: Urinary infections
Ciprofloxacin
Inhibits DNA gyrase
Urinary tract infections

Sulfonamides (sulfa drugs)

Inhibit folic acid synthesis
Broad spectrum
Bacteriostatic

Antifungal drug

Polyenes
Amphotericin B
Inhibition of ergosterol synthesis

Antifungal drug

Azoles
Miconazole
Triazoles
Treatment of cuteneous mycoses, (athlet's foot, Yeast infection)

Antiviral drug

Nucleoside and nucleotide analogs
attachment uncoating

Antibiotic ressistance

A variety of mutations can lead to antibiotic resistance
Mechanisms of antibiotic resistance
Enzymatic destruction of drug
Prevention of penetration of drug
Alteration of drug's target site
Rapid ejection of the drug
Resistance genes are often on plasmids or transposons that can be transferred between bacteria
Misuse of antibiotics selects for resistance mutants. Misuse includes
Using outdated or weakened antibiotics
Using antibiotics for the common cold and other inappropriate conditions
Using antibiotics in animal feed
Failing complete the prescribed regimen
Using someone else's leftover prescription

Synergism

occurs when the effect of two drugs together is greater than the effect of either alone

Antagonism

occurs when the effect of two drugs together is less than the effect of either alone

1)

Penicillin was considered a "miracle drug" for all of the following reasons except
A)

It was the first antibiotic.
B)

It doesn't affect eukaryotic cells.
C)

It inhibits gram-positive cell wall synthesis.
D)

It has selective toxicity.
E)

None of the above.

...A

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