IMSE311(FINALS): BACTERIAL INFECTIONS

The collection of microorganisms that exists on the body-bacteria, viruses, and single-celled prokaryotic organisms is called the _____

HUMAN MICROBIOME

A type of relationship wherein neither organism is harmed or benefited.

Commensalism

A type of human-microbe relationship where both organisms benefit from one another.

Mutualism

A type of human-microbe relationship where the host is harmed

Parasitism

The ability of a pathogen to establish infection, often measured by how many exposed individuals become infected.

Infectivity

The inherent capacity of an organism to cause disease by its genetic makeup

Pathogencity

Refers to The degree of damage caused by a microbe

Virulence

TRUE OR FALSE

Bacteria lack a nucleus and membrane-bound organelles but have

ribosomes, plasmids, and inclusion bodies.

TRUE

MODIFIED TRUE OR FALSE

Statement 1: Gram Positive Bacteria do not possess a peptidoglycan; hence, they have a thin cell wall.

Statement 2: Gram Negative bacteria possess lipopolysaccharide and Lipid A which can be fatal.

A. Statement 1 is true

B. Statement 2 is true

C. Both statements are true

D. Both statements are false

B.

Structure that help bacteria in locomotion and attachment

Flagella

A structure of bacteria which enable binding to host cells, resist phagocytosis, and undergo antigenic variation

Fimbriae/pili

A structural component of bacteria which consist of surface molecules bind that host receptors

Afimbrial Adhesins

A structure of bacteria which is a polysaccharide layer that blocks phagocytosis, antibody binding, and complement activation.

Capsule

What is the main virulence factor of Streptococcus pneumoniae?

Capsule

An extracellular virulence factor of bacteria that break down host defenses,

damage tissue, and aid spread.

Invasins

Found in gram-negative LPS, is released when cells die and riggers cytokine release

Lipid A (Endotoxin)

Exotoxins are mostly produced by:

A. Gram positive bacteria

B. Gram negative bacteria

A.

This type of exotoxins block protein synthesis

Cytotoxin

This type of exotoxins produce spams and paralysis

Neurotoxins

A type of exotoxin which cause diarrhea and inflammation

Enterotoxins

Match the following:

1. Diphtheria toxin

2. Botulinum toxin

3. Tetanospasmin

4. Difficile Toxin A

5. Difficile Toxin B

A. Cytotoxins

B. Neurotroxins

C. Enterotoxins

1. A

2. B

3. B

4. C

5. A

Antigens which Hyperactivate T cells, causing massive cytokine release ‚ leading to toxic shock syndrome.

Superantigens

Syphilis is also known as:

1. French Disease

2. Spanish Disease

3. Great Pox

4. Evil Pox

Treponemal specie which cause human syphilis

Treponema pallidum subspecies pallidum

Treponemal specie which cause yaws

Treponema pallidum subspecies pertenue

Treponemal specie which cause non-venereal endemic syphilis

Treponema pallidum subspecies endemicum

Causative agent of pinta

Treponema carateum

Syphilis in which rabbits are affected is caused by

Treponema cuniculi

Match the following:

1. Chancre

2. Gummas

3. Condylomata lata

4. No clinical symptoms

A. Early Syphilis

B. Secondary Syphilis

C. Latent syphilis

D. Tertiary Syphilis

1. A

2. D

3. B

4. C

MODIFIED TRUE OR FALSE

1. Serological tests are the gold standard method in detecting primary syphilis.

2. Darkfield microscopy is one of the diagnostic methods for detecting secondary syphilis.

A. Statement 1 is true

B. Statement 2 is true

C. Either

D. Neither

B.

A stage of syphilis characterized by lack of clinical symptoms

Latent Syphilis

TRUE OR FALSE

A pregnant individual with a latent syphilis tend to be non-infectious

FALSE

How is tertiary syphilis diagnoses?

By Reactive Serological Test or Reactive Spinal Fluid Test

A direct detection of Treponema which detects T. pallidum in lesion fluid

Darkfield microscopy

TRUE OR FALSE

Darkfield microscopy requires live motile organisms

TRUE

Methods using labeled antibodies; HIGHLY SPECIFIC, and can use fixed slides

Fluorescent Antibody Tests

What does non-treponemal test detect?

Reagin Antibodies

Titers for non-treponemal test peak in what stage of syphilis?

Secondary stage

A positive result can be obtained for non-treponemal test _____ after chancre

1-4 weeks

Match the following:

1. Pregnancy

2. Prozone

3. Infections

4. Postzone

5. Autoimmune disease

A. FALSE POSITIVE

B. FALSE NEGATIVE

1. A

2. B

3. A

4. B

5. A

Tests which detect antibodies specific to T. pallidum

Treponemal Tests

Match the following:

1. FTA-ABS

2. TPPA

3. EIA

4. VDRL

5. RPR

6. CLIA

7. MFI

A. Confirmatory

B. Screening

1. A

2. A

3. A

4. B

5. B

6. A

7. A

Match the following:

1. Used to monitor treatment

2. Useful in late syphilis

3. More specific

4. Cannot distinguish active vs. past infection

5. Less sensitive in neurosyphilis

A. Screening

B. Confirmatory

1. A

2. B

3. B

4. B

5. B

Traditional testing of syphilis involves screening with ____ and confirm it with ____

Non-treponemal; Treponemal

Reverse Sequence testing of syphilis are screened with ______ and is confirmed with ______ for discrepancies

Automated treponemal; Non-treponemal or TP-PA

Molecular testing is highly sensitive in what stage of syphilis

Primary Syphilis

Gold standard method for diagnosing neurosyphilis

CSF VRDL

What are the supportive findings of a neurosyphilis?

A. Increased lymphocyte, decreased protein

B. Increased monocyte, decreased protein

C. Increased lymphocyte, increased protein

D. Decreased monocyte, decreased protein

C

Bacteria that cause Group A Streptocoocal infection

Streptococcus pyogenes

Hemolysis produced by GAS in BAP

B-hemolysis

A main component of Streptococcus pyogenes that inhibit phagocytosis, reduce complement deposition and aids attachment

M Protein

responsible for scarlet fever

ExoToxins (SpeA, SpeC)

A sequeale of GAS which occurs 2-3% of the time after pharyngitis and wherein autoimmune cross reactivity happen

Acute Rheumatic Fever

A sequelae of GAS characterized by immune deposition in kidneys

Post-streptococcal Glomerulonephritis

Rapid Antigen Detection used for GAS

Lateral Flow Assays

A 2-fold increase in titer of streptozyme test is considered:

A. Significant

B. Not significant

B.

Gram-negative, spiral, microacrophilic bacterium, which is a major cause of gastric & duodenal ulcers

Helicobacter Pylori

Virulence Factor of H. pylori which is injected into gastric cells, disrupting signal and cytoskeletons

CagA Protien

A virulence factor of H. pylori linked to ulcers and carcinoma

VacA Toxin

Match the following virulence factors of H. pylori to its function:

1. Spiral Shape and Flagella

2. Urease

3. Flagellar Sheath

A. Production of ammonia and neutralization of acid

B. Motility and Mucus penetration

C. Protection from acid

1. B

2. A

3. C

What can be the long term risk of infection with H. pylori

Gastric Carcinoma

What is the enzyme detected in endoscopy and biopsy to confirm infection with H. pylori?

Urease

Most specific test for H. pylori but has low sensitivity

Culture

Presence of urease in detecting H. pylori is indicated by a color change. what will be its color upon reaction if positive?

A. Pink to yellow

B. Yellow to pink

C. Yellow to Red

D. Red to Yellow

B,

Most reliable immunoglobulin used for diagnosis of H. pylori since it remain elevated even if untreated

IgG

The serological test considered as the method of choice for H. pylori

ELISA

Considered to be the smallest free living organisms

Mycoplasma pneumoniae

MODIFIED TRUE OR FALSE

1. Mycoplasma pneumoniae’s main virulence factor is its cell wall.

2. Hence, penicillin is a great choice for treating M. pneumoniae since it directly attacks the cell wall.

A. Statement1. is true

B. Statement 2 is true

C. Either

D. Neither

D.

This is said to be the leading cause of respiratory infections worldwide

Mycoplasma pneumoniae

Mode of transmission of M. pneumoniae

Respiratory Droplets

Skin or mucosal emergency

A. Stevens-Johnson

B. Rauvnaud

A.

Cold-induced vasospasm of digits

A. Stevens-Johnson

B. Rauvnaud

B,

A bacteria that show a fried egg appearance upon culture

Mycoplasma pneumoniae

A diagnostic tool that was historicaly used for detection of M. pneumoniae but is non specific hence not recommended

Cold Agglutinin Test

Mode of Transmission of Rickettsial Infections

Arthropod-borne / Vector Borne except R. prowazekii

Match the following Organisms to the disease they cause

1. R. rickettsii

2. R. japonica

3. R. felis

4. R. akari

5. R. typhi

6. R. prowazekii

A. Flea-borne spotted fever

B. Rickettsial pox

C. Epidemic typhus

D. Rocky Mountain Spotted Fever

E. Endemic typhus

F. Japanese spotted fever

1. D

2. F

3. A

4. B

5. E

6. C

Determine the appropriate vector of:

1. R. rickettsi

2. R. japonica

3. R. felis

4. R. akari

5. R. typhi

6. R. prowazekii

A. Tick

B. Mites

C. Fleas

D. Lice

E. NOTA

1. A

2. A

3. E

4. B

5. C

6. D

What is the target of rickettsial infections?

Vascular endothelium

Gold standard method for detecting Rickettsial infection

Indirect Immunofluorescence Assay (IFA) with paired sera (24-fold rise)

Obligate intracellular, Gram negative-like coccoid bacteria characterized by a unique biphasic cycle

Chlamydia trachomatis

Gram negative diplococci kidney shaped fastidious bacteria.

Neisseria meningitidies

A disease caused by Neisseria meningitidis characterized by photphobia

A. Meningitis

B. Meninogococcemia

A.

A group of symptoms caused by N. meningitidis resulting from the failure of adrenal glands to function normally as a result of bleeding into the gland

Waterhouse-Friedrichsen syndrome

Culture media used for detection of N. meningitidis

Chocolate agar, with CO2

To detect the capsular antigen of N. meningitidis, _____ can be employed

LATEX AGGLUTINATION

A gram negative pleomorphic coccobacilli that has the Greek word meaning of “blood-lover”

Haemophilus spp.

What are the requirements of Haemophilus for growth?

1. X factor (hemin)

2. V Factor (NAD)

Detection of antigens of Haemophilus spp. is done by?

Latex Agglutination

Major cause of childhood meningitis

Haemophilus influenzae type B (HiB)