exam 5 study guide review

what symptoms and presentations can be associated with infection by Streptococcus pyogenes? 

sore throat, fever, swollen tonsils and skin infections

what causes some of the symptoms associated with infection by Streptococcus pyogenes? 

bacterial toxins and immune response

slow-growing, chronic infection that’s often latent; granuloma formation are characteristics of what?

Mycobacterium tuberculosis

what type of cell structure does Mycobacterium tuberculosis have?

a waxy mycolic acid cell wall

how does the waxy mycolic acid cell wall in Mycobacterium tuberculosis contribute to persistence and virulence? 

helps with resisting phagocytosis and antibiotics

why might a slow-growing bacterium like M. tuberculosis cause chronic infection?

the bacteria can remain dormant by hiding from immune cells and reactivate later on

what’s the vaccine for M. tuberculosis?

Bacillus Calmette-Guérin (BCG) vaccine

how can M. tuberculosis be prevented at a community level?

BCG vaccination in endemic areas, screenings for early detection, isolation

Acute, highly contagious respiratory infection; paroxysmal cough  are characteristics of what?

Bordetella pertussis

what type of cell structure does Bordetella pertussis have?

a gram-negative, small, short rod-shaped bacterium

how do the toxins (pertussis toxin) in Bordetella pertussis contribute to persistence and virulence? 

by damaging ciliated epithelial cells which impairs clearance

since Bordetella pertussis is a rapid toxin-mediated disease, what type of infection occurs?

acute

why is the bacteria, Bordetella pertussis, so contagious?

it spreads easily via respiratory droplets from coughing and sneezing 

what’s the vaccine for Bordetella pertussis?

DTaP (diphtheria, tetanus, acellular pertussis) 

how can Bordetella pertussis be prevented at a community level?

with routine vaccination (DTaP/Tdap), booster doses, hygiene covering coughs

what are common transmission mechanisms of respiratory infections?

droplets, aerosols, fomites (contaminated surfaces), sometimes direct contact

what are the most common causes of a cold?

Rhinoviruses, coronaviruses, adenoviruses, RSV in some cases

what symptoms typically accompany a cold?

runny/stuffy nose, sneezing, mild sore throat, cough, low-grade fever, malaise

what populations are most affected by influenza?

all ages, more severe in elderly & immunocompromised

what populations are most affected by RSV?

infants, young children, and elderly

what are the different types of influenza?

A, B, C, D

more severe symptoms; can cause seasonal epidemics and global pandemics

influenza A

causes seasonal epidemics and severe illness in young children or older adults

influenza B

type of influenza that causes mild respiratory illness or no symptoms at all

influenza C

primarily affects cattle and is not known to cause illness in people

influenza D

what is the most severe type of influenza?

mostly A. sometimes B

what are the different types of RSV?

A and B

RSV can cause what in infants?

bronchitis

the mechanism of viral damage in influenza involves what?

direct epithelial cell death in respiratory tract and immune-mediated inflammation

what is the mechanism of viral damage in RSV?

syncytial cell formation that causes airway obstruction

how does antigenic drift and shift affect yearly vaccine formulation for RSV and influenza?

antigenic drift and shift cause influenza viruses to change frequently, so the vaccine must be updated each year, while RSV changes very little, so its vaccine doesn’t need yearly reformulation

if you were designing a vaccine program, why would RSV and influenza require different strategies?

RSV causes severe disease in infants and elderly while influenza changes rapidly, requiring yearly updates for everyone

what are upper respiratory infections?

pharyngitis, otitis media, sinusitis

which is a lower respiratory infection?

pneumonia

pharyngitis can be what?

viral (common cold) or bacterial (S. pyogenes; strep)

otitis media can be what?

viral or bacterial

sinusitis can be what?

viral or bacterial

pneumonia can be what?

• bacterial (S. pneumoniae, Legionella)

• viral (influenza, RSV)

• fungal (immunocompromised)

what symptoms signal a transition from upper → lower infection?

fever, productive cough, shortness of breath, chest pain

why might untreated “strep throat” lead to systemic diseases like rheumatic fever?

immune response can mis-target host tissues

what features of modern environments are causing Legionella bacteria to form biofilms and aerosolize?

still water in AC systems, hot tubs, plumbing, and fountains

how is the method of transmission for Legionella pneumophila different from direct person-to-person transmission?

it requires environmental aerosolization so it doesn’t spread easily between people

how could hospitals reduce risk of Legionella and Pseudomonas infections?

• regular disinfection of water systems,

• preventing stagnant water zones,

• ensuring proper ventilation to reduce aerosol buildup

• isolating at-risk patients

Why are immunocompromised patients (e.g., with HIV) more susceptible to fungal pneumonias like Pneumocystis jirovecii? (Pneumocystic pneumonia)

their weakened immune system can’t clear opportunistic fungi so alveoli fills with organisms creating pneumonia

Explain how hospital ventilation systems or aspiration can lead to Healthcare-Associated Pneumonia (HAP)

contaminated air or equipment can introduce bacteria into the lungs, and aspiration allows mouth or stomach bacteria to enter the airway, causing infection in vulnerable patients.

what symptoms does H. pylori cause?

gastritis and peptic ulcers; long-term infection can increase the risk of stomach cancer if left untreated

what factors are associated with/lead to C. difficile infections?

gut flora being killed by antibiotics which allows bacteria to overgrow, produce toxins, and cause colitis

Compare Salmonella, Shigella, E. coli, and Campylobacter:

Which bacterium is the most common cause of diarrhea in the US?

campylobacter 

What foods or environments are associated with salmonella?

poultry and eggs

What foods or environments are associated with shigella?

Person-to-person thru contaminated water and food

What foods or environments are associated with E. coli?

beef, produce, water

What foods or environments are associated with campylobacter?

poultry and milk

which bacterium produce toxins?

Clostridium, Shiga toxin, Staphylococcus, Bacillus, E. coli, and Streptococcus

which bacterium invade tissues?

Shigella, Salmonella, Campylobacter, EIEC

Which bacterial toxins are associated with acute food poisoning?

• staphylococcus aureus heat-stable enterotoxins

• bacillus cereus emetic toxin (cereulide)

• clostridium perfringens enterotoxin

• Shiga toxin from Shiga toxin-producing E. coli (STEC)

Which bacterium are zoonotic?

salmonella, E.coli, and campylobacter

Why might antibiotic use sometimes make GI infections worse (e.g., C. difficile)?

• antibiotics disrupt normal gut microbiota, reducing beneficial bacteria

• giving GI infections opportunity to grow or release toxins

how do norovirus outbreaks occur?

through contaminated food, water, or surfaces via fecal-oral

where do norovirus outbreaks occur?

cruise ships, schools, nursing homes, and restaurants 

how do rotavirus outbreaks spread since it can survive on hands and surfaces for hours?

among young children via fecal-oral route

where do rotavirus outbreaks spread?

daycare centers, hospitals, households with infants

Connect the symptoms of viral diarrhea to their mechanism

• viruses damage the intestinal villi

• creating poor absorption

• leading to watery diarrhea and dehydration

Why does rehydration therapy (not antibiotics) save lives in cholera and rotavirus?

• they’re caused by toxins or viral damage

• making antibiotics ineffective

• therapy treats the dehydration to prevent shock and restore circulation

what’s the life cycle/migration of pinworm (enterobius)?

• eggs swallowed

• hatch in the intestines

• adults live colon

• females lay eggs around the anus

• gets spread by scratching and re-ingestion

what’s the life cycle/migration of roundworm (Ascaris)?

• human eats eggs

• they hatch into larvae in small intestine

• then migrate though blood to lungs

• later maturing in small intestine

how are the eggs from pinworm (enterobius) transmitted?

eggs on hands and bedding

how are the eggs from roundworm (Ascaris) transmitted?

contaminated soil and food

How might sanitation and education campaigns target specific stages of the life cycle/migration in pinworm (enterobius)?

with handwashing and clean bedding

How might sanitation and education campaigns target specific stages of the life cycle/migration in roundworm (Ascaris)?

with handwashing, proper disposal of feces, washing produce, and wearing shoes

what is the genetic composition of Hepatitis A (HAV) and Hepatitis C (HCV)?

RNA

what is the route of transmission for Hepatitis A (HAV)?

close contact with an infected person or contaminated food/water

is Hepatitis A (HAV) a chronic or acute infection?

acute; self-limiting

is there a vaccine for Hepatitis A (HAV)?

yes:)

what is the genetic composition of Hepatitis B (HBV)?

DNA; partially double-stranded

what is the route of transmission for Hepatitis B (HBV)?

blood, sexual, mother to child

is Hepatitis B (HBV) a chronic or acute infection?

both

is there a vaccine for Hepatitis B (HBV)?

yes!

what is the route of transmission for Hepatitis C (HCV)?

blood thru needles or transfusion

is Hepatitis C (HCV) a chronic or acute infection?

chronic (often)

is there a vaccine for Hepatitis C (HCV)?

no

Why does HBV remain a concern for healthcare workers even after a needle has dried?

it’s still infectious

how does bacteria in dental plaque form a biofilm?

by attaching to enamel creating a sticky polysaccharide that traps more microbes

dental plaque biofilm can lead to what?

caries, gingivitis, and periodontitis 

how does poor oral hygiene connect to systemic disease?

bacteria can enter bloodstream through damaged gums creating endocarditis or worsen heart disease

why might Vitamin K production by E. coli be both beneficial and risky?

gut flora can create Vitamin K which aids clotting but E. coli can cause infection like UTI or sepsis if it leaves the gut

Trace how E. coli from the GI tract can cause a UTI

GI tract → urethra → bladder

Why are females more prone to infection?

shorter urethra so shorter distance for bacteria to reach the bladder

How might catheter use increase risk?

they provide a direct pathway for bacteria to enter the bladder

How could hospital hygiene reduce endogenous transfer?

using good hand hygiene, proper catheter care, and sterile technique

the type of organism and structure gonorrhea is what?

neisseria gonorrhoeae; gram negative diplococcus

what are the typical symptoms of gonorrhea in males vs. females?

a thick, yellow, or green discharge & burning pee

what are some long term complications of gonorrhea?

PID, infertility, and neonatal conjunctivitis 

what type of organism and its structure is chlamydia?

chlamydia trachomatis; obligate intracellular bacteria; gram-negative like cell wall

what are the typical symptoms of chlamydia in males vs. females?

often causes no symptoms; can lead to discharge and burning pee pelvic pain/bleeding in females and testicular pain in males

what are some long term complications of chlamydia?

chronic pelvic pain, PID, infertility

what is the structure and organism of syphilis? (can’t be seen on gram stain)

gram negative treponema pallidum; thin spiral shaped structure

what are the typical symptoms of syphilis in males vs. females?

Primary stage: Painless sore (chancre) at the infection site
Secondary stage: Skin rash, mucous membrane lesions, fever, fatigue, and swollen lymph nodes.
Latent/tertiary stages: affect heart, brain, and nerves

what are some long term complications of syphilis?

neurologic disease, cardiovascular destruction, congenital syphilis

Which bacterial STI is most common in the US?

chlamydia