Microbiology Quiz on Viruses and Pathogens

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Questions and Answers

Which virus is more commonly associated with adults?

Norovirus (correct)

Bacillus cereus

Rotavirus

Escherichia coli

What is a hallmark symptom of infection with Escherichia coli O157-H7?

Severe abdominal cramps

Bloody diarrhea (correct)

Fever and chills

Nausea and vomiting

What is the primary causative agent of stomach ulcers?

Norovirus

MRSA

Salmonella

Helicobacter pylori (correct)

Which condition occurs when organisms multiply in the blood?

Septicemia Signup and view all the answers

What is the primary vaccine available for gastrointestinal diseases?

Rotavirus vaccine Signup and view all the answers

What can untreated pharyngitis caused by Streptococcus pyogenes lead to?

Glomerulonephritis or rheumatic fever Signup and view all the answers

Which pathogen is associated with beta-hemolysis?

Streptococcus agalactiae Signup and view all the answers

What characteristic differentiates prion P r P from normal cellular P r P?

Structure has β-pleated sheets Signup and view all the answers

Which of the following is true about naked viruses compared to enveloped viruses?

Enveloped viruses are more susceptible to heat and detergents. Signup and view all the answers

What is the main source of nutrition for fungi?

Dead and decaying tissues Signup and view all the answers

What skin condition is caused by Malassezia furfur fungus?

Pityriasis versicolor Signup and view all the answers

Which of these viruses would likely have a spike and an envelope?

Enveloped virus Signup and view all the answers

Streptolysin O is associated with which type of infection?

Streptococcus infection Signup and view all the answers

What is a hallmark symptom of the condition mentioned involving increased breathing rate?

Low blood pressure Signup and view all the answers

What is the primary vector responsible for the spread of Borrelia burgdorferi?

Ticks Signup and view all the answers

Which of the following is NOT a typical symptom of Lyme disease?

Loss of appetite Signup and view all the answers

Which condition is an example of a post-infection sequela related to Streptococcus pyogenes?

Post-streptococcal glomerulonephritis Signup and view all the answers

What determines the spectrum of clinical signs and symptoms associated with HIV infection?

Levels of virus and T cells in the blood Signup and view all the answers

What is the retrovirus responsible for HIV infection classified as?

Lentivirus Signup and view all the answers

What capability is unique to retroviruses like HIV?

Integrating viral genes into the host genome Signup and view all the answers

Which of the following symptoms is associated with the initial stage of HIV infection?

Fever Signup and view all the answers

Which disease is most commonly associated with respiratory droplets?

Tuberculosis Signup and view all the answers

Which symptom is a hallmark of viral hepatitis?

Jaundice Signup and view all the answers

Which of the following diseases is spread through blood products?

Hepatitis B Signup and view all the answers

What is a typical sign associated with primary syphilis?

Chancre Signup and view all the answers

Which condition is characterized by abdominal cramping and can be caused by foodborne pathogens?

Food poisoning Signup and view all the answers

What is the primary causative agent of influenza?

Influenza A, B, and C viruses Signup and view all the answers

What role does neuraminidase (N) play in the influenza virus's pathogenesis?

Breaks down mucous in the respiratory tract Signup and view all the answers

Which feature of Mycobacterium tuberculosis contributes to its virulence?

Presence of mycolic acid Signup and view all the answers

What unique characteristic is associated with Mycoplasma pneumoniae?

It is without a cell wall. Signup and view all the answers

What significant respiratory issue can result from the 2009 H1N1 variant?

Massive cytokine storm Signup and view all the answers

What is a common sign of tuberculosis in its initial stages?

Minor cough and mild fever Signup and view all the answers

How does the influenza virus interact with ciliated cells of the respiratory mucosa?

By binding to these cells Signup and view all the answers

What symptom is commonly observed in patients infected with the 2009 H1N1 strain of influenza?

Gastrointestinal distress Signup and view all the answers

What is the main causative agent of catheter-associated urinary tract infections (CA-UTIs)?

Escherichia coli Signup and view all the answers

Which of the following correctly describes Treponema pallidum?

A spirochete with complex growth requirements Signup and view all the answers

During which stage of syphilis is the spirochete transmissible?

During the primary and secondary stages Signup and view all the answers

Which organism is most associated with malaria?

Plasmodium species Signup and view all the answers

What type of organism is T.pallidum classified as?

Gram-negative bacteria Signup and view all the answers

Which of the following diseases is caused by a protozoan?

Trichomoniasis Signup and view all the answers

Which organism is primarily responsible for brucellosis?

Brucella species Signup and view all the answers

What is a common sign of secondary syphilis?

Rash and flu-like symptoms Signup and view all the answers

Study Notes

Normal Microbiota

Sites previously known to harbor normal microbiota: skin and adjacent mucous membranes, upper respiratory tract, gastrointestinal tract (including mouth), and outer portion of urethra.
Additional sites now thought to harbor normal microbiota (or their DNA): lungs (lower respiratory tract), bladder (and urine), breast milk, amniotic fluid, and fetus.
Sites where DNA from microbiota has been detected: brain, bloodstream.

Bacterial and Streptococcal Infections

Beta-hemolytic staphylococci & streptococci examples: Streptococcus pyogenes, Streptococcus agalactiae, Staphylococcus aureus.
These pathogens produce beta-hemolyse, causing erythrocyte hemolysis.
Diagnosis of strep infection: Rapid test for the presence of Streptolysin O, Antistreptolysin O titer (ASO). Positive titer >200 IU/mL.
ASO titer rises to a peak at 4-6 weeks post-infection and may remain elevated for 1 year.
ASO test is positive in streptococcal infections (eg., upper airway infections, scarlet fever), post-streptococcal infection complications (eg., glomerulonephritis and rheumatic fever).
ASO test can be falsely positive in some bacterial infections.
Streptococcus infection may cause pharyngitis, which can lead to glomerulonephritis (kidney) or rheumatic fever (heart) if left untreated.

Viruses: Naked and Enveloped

Viruses are classified as naked or enveloped.
Naked viruses have a nucleocapsid, which consists of a capsid and nucleic acid.
Enveloped viruses have a similar nucleocapsid but are also enclosed in an outer envelope.

Prions

Prion characteristics: proteinaceous infectious agents made by all mammals.
Normal prion PrP has α-helices.
Disease-causing prion PrP has β-pleated sheets.
Prion PrP causes cellular PrP to refold into prion PrP.
Illustrations of normal brain tissue and spongiform encephalopathy brain are provided.

Skin Infections

Fungi are decomposers/saprophytes that gain nutrition from dead and decaying tissues.
Skin's superficial layer, stratum corneum, is composed of dead skin cells, making it a frequent site for fungal infections.
Pityriasis versicolor (tinea versicolor) is caused by Malassezia furfur fungus.
It's characterized by more or less pigmentation of skin (hyperpigmented or hypopigmented).

Gastrointestinal Tract Infections

Norovirus and rotavirus cause stomach problems: nausea, vomiting, and diarrhea.
Norovirus is more common in adults.
Rotavirus primarily affects infants and young children.
A vaccine is available for rotavirus, but not for norovirus.

Food Poisoning

Causative agents of food poisoning: Bacillus cereus, E.coli 0157-H7, and other bacteria.
Bacillus cereus causes emetic or diarrheal food poisoning.
Emetic type is associated with cooked rice or starches left at room temperature for prolonged periods.
Diarrheal type results from improperly stored meat and prepared meals.
Escherichia coli 0157-H7 is characterized by bloody diarrhea.
Shiga toxin produced by E. coli 0157-H7 causes damage to the intestine and systemic effects.
Shiga toxin inhibits protein synthesis within target cells similar to ricin.

Stomach Ulcers & Cancer

Helicobacter pylori causes stomach ulcers and cancer.
H. pylori bacteria invade gastric mucus and attach to gastric epithelial cells.
H. pylori, toxins, and inflammation cause the layer of gastric mucus to become thin.
Gastric acid damages the epithelial cells and underlying tissue.

Cardiovascular and Lymphatic Infections

Septicemia occurs when organisms multiply in the blood.
Many bacteria and viruses can cause septicemia, with MRSA being a common cause.
Fungal infections account for around 10% of cases.
Common symptoms include fever, altered mental state, shaking, chills, gastrointestinal symptoms, increased breathing rate (with respiratory alkalosis), and low blood pressure.

Systemic Blood Infections

Systemic blood infections caused by Streptococcus mutans and Staphylococcus aureus can progress to endocarditis.
Post-streptococcal glomerulonephritis (PSGN) is a complication of pharyngitis or skin infections caused by Streptococcus pyogenes.

Chagas Disease

Chagas disease is caused by Trypanosoma cruzi (protozoan).
Symptoms include swelling at the infection site, fever, fatigue, malaise, body aches, headache, and loss of appetite.
In the South-East of the US, infected people might develop fatal congestive heart failure 10-20 years after initial symptoms.

HIV Infection and AIDS

A spectrum of clinical signs and symptoms associated with HIV.
Symptoms tied to virus levels in the blood and T-cell levels.
Initial symptoms include fatigue, diarrhea, weight loss, and neurological changes.
Opportunistic infections or cancers can also develop.
HIV is a retrovirus in the Lentivirus genus.
Retroviruses have the potential to cause cancer and modify host DNA.
Retroviruses contain reverse transcriptase (RT), which catalyzes the replication of DNA from single-stranded RNA.
Viral genes integrate into the host genome, passed on to progeny cells.

Respiratory System Infections

Influenza A, B, and C viruses (Orthomyxoviridae) are causative agents.
Possess a lipoprotein envelope, glycoprotein spikes (hemagglutinin (H) and neuraminidase (N)) and ion channels; ssRNA genome.
10 genes on 8 RNA strands, contributing to variations.
Influenza virus binds to ciliated cells of the respiratory mucosa, leading to severe inflammation and "cytokine storm".
Hemagglutinin (H) binds to host cell receptors.
Neuraminidase (N) aids in viral budding and release, affecting respiratory tract mucous.
2009 H1N1 (Swine flu) variants demonstrate efficient binding to lower respiratory tract, causing cytokine storm, with differing manifestations.

Bacterial Diseases of the Lower Respiratory System

Tuberculosis (TB) is a leading global killer, with declining incidence in developed nations.
TB is caused by Mycobacterium tuberculosis.
The presence of mycolic acid is a crucial characteristic, contributing to features like slow growth, resistance to macrophages, and antimicrobial drugs.
Mycoplasma pneumoniae is a very small bacterium without a cell wall; the causative agent of walking pneumonia, often mimicking ventilator-associated pneumonia.

Genitourinary System Infections

Urinary tract infections (UTIs) can be acquired in healthcare facilities or outside.
95% of UTIs originate from normal gastrointestinal tract biota, with Escherichia coli accounting for 80%.
Other causative agents include Staphylococcus saprophyticus and Enterococcus.

Syphilis

Treponema pallidum is the causative agent; a spirochete with thin, coiled structure.
Gram-negative, requiring cultivation in living host cells.
Marked by primary, secondary, and tertiary stages, along with varying latent periods.
Spirochetes are present in lesions and blood cultures during primary and secondary stages and are transmissible at these times, including the early latency period.
Transmission is largely absent during the "late latent" and tertiary stages.

Infectious Diseases (Match-Up)

Various matching questions are presented and information is included for disease, animal, symptom, organism type matching.

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Description

Test your knowledge on viruses, bacteria, and fungi with this microbiology quiz. It covers key concepts such as common pathogens, their associated symptoms, and characteristics. Ideal for students looking to reinforce their understanding of microbiological principles.