Microbiology Quiz: Bacteria Functions

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Questions and Answers

What is the primary function of the cell membrane in bacteria?

Genetic material protection

Energy storage

Protein synthesis

Selective barrier for solutes (correct)

Which type of structure allows spirochetes to move in a corkscrew motion?

Fimbriae

Flagella

Pili

Axial filament (correct)

In which phase of microbial growth does the number of replications equal the number of deaths?

Stationary Phase (correct)

Log Phase

Lag Phase

Death Phase

What is the role of pili in bacterial behavior?

Conjugation and attachment to other bacteria Signup and view all the answers

Which class of bacteria thrives in extremely cold environments?

Psychrophiles Signup and view all the answers

What is the primary means of transmission for Leptospira interrogans?

Through mucous membranes or skin breaks Signup and view all the answers

What kind of symptoms are associated with Anicteric Leptospirosis?

Mild, flu-like symptoms Signup and view all the answers

Which of the following is a recognized treatment for mild cases of Rickettsia infections?

Doxycycline Signup and view all the answers

What is the causative agent of Lyme Disease?

Borrelia burgdorferi Signup and view all the answers

What vector is associated with Borrelia burgdorferi infection?

Ixodes tick Signup and view all the answers

In Rickettsia infections, which symptom is part of the classic triad?

Fever Signup and view all the answers

What is a significant complication of severe Leptospira interrogans infection?

Pulmonary hemorrhage Signup and view all the answers

What is the recommended prophylaxis for Leptospira interrogans exposure?

Doxycycline 200mg OD for 3-5 days Signup and view all the answers

What characterizes plasmids in bacteria?

Extrachromosomal circular dsDNA Signup and view all the answers

Which methods of gene transfer involves the uptake of naked DNA?

Transformation Signup and view all the answers

Which of the following is an example of a thermophile?

Bacillus Signup and view all the answers

What type of organisms require alkaline or basic pH for growth?

Alkaliphiles Signup and view all the answers

What is a characteristic of obligate aerobes?

They require O2 for survival. Signup and view all the answers

Which of the following is a characteristic of transposable elements?

They are often referred to as jumping genes. Signup and view all the answers

Which agar plate would be used to culture organisms that require high protein diets?

Milk Agar Signup and view all the answers

What distinguishes halophiles from other organisms?

They thrive in high salt concentrations. Signup and view all the answers

Which of the following is a trait of chemotrophs?

They use chemical reactions for energy. Signup and view all the answers

Which of the following is true regarding chromatin regions in bacteria?

They contain circular dsDNA. Signup and view all the answers

What is the primary transmission method of leishmaniasis?

Bite from infected sandflies Signup and view all the answers

Which of the following is NOT a symptom of advanced leishmaniasis infection?

Severe rash Signup and view all the answers

What type of examination is used for diagnosing chronic strongyloidiasis?

Stool exam Signup and view all the answers

Which treatment is appropriate for severe cases of leishmaniasis?

Clindamycin + Quinine Signup and view all the answers

The condition known as 'Oriental sore' is also referred to as?

Delhi boil Signup and view all the answers

Which helminth is primarily associated with eating raw or improperly cooked meat?

Trichinella spiralis Signup and view all the answers

What are common symptoms of Trichinella spiralis infection?

Eosinophilia and myalgia Signup and view all the answers

What type of organism is Enterobius vermicularis?

Nematode Signup and view all the answers

Which of the following is a symptom commonly associated with leishmaniasis?

General malaise and fever Signup and view all the answers

What can be detected through muscle biopsy in Trichinella spiralis infection?

Larval worms Signup and view all the answers

Which organism is primarily associated with acute bacterial epiglottitis?

Haemophilus influenzae Signup and view all the answers

What is the recommended treatment for Shigella dysenteriae infection?

Ciprofloxacin Signup and view all the answers

What is the characteristic presentation of Brucella infection?

Undulant fever Signup and view all the answers

Which of the following bacteria is associated with whooping cough?

Bordetella pertussis Signup and view all the answers

What type of pathogen is Salmonella classified as?

Zoonotic infection Signup and view all the answers

Which microorganism is associated with the presentation of dysentery?

Shigella sonnei Signup and view all the answers

What is the most common cause of urinary tract infections (UTIs)?

Escherichia coli Signup and view all the answers

Which bacteria is known for producing the Shiga toxin?

Shigella dysenteriae Signup and view all the answers

What is the mode of transmission (MOT) for Pasteurella multocida?

Dog or cat scratch Signup and view all the answers

Which organism is known to be oxidase positive and associated with a fruity smell?

Pseudomonas aeruginosa Signup and view all the answers

Which pathogen is known for causing enterocolitis and can sometimes be mistaken for appendicitis?

Yersinia enterocolitica Signup and view all the answers

What is the treatment for an active infection caused by Francisella tularensis?

Streptomycin Signup and view all the answers

Which pathogen is responsible for causing typhoid fever?

Salmonella typhi Signup and view all the answers

Which of the following is NOT a common treatment option for Enterohemorrhagic E. coli (EHEC)?

Antibiotics Signup and view all the answers

Study Notes

Leptospira interrogans

Mode of Transmission: Through mucous membranes or skin breaks; contact with contaminated water from infected urine (rodents, cats, dogs, humans).
Presentation includes leptospiremia and leptospiruria, with anicteric leptospirosis characterized by mild flu-like symptoms.
Severe cases may lead to meningitis, renal failure, liver failure, with pulmonary hemorrhage as a common cause of death.
Prophylaxis with Doxycycline (200 mg once daily for 3-5 days) recommended.
Treatment:
- Mild cases: Doxycycline
- Moderate to severe cases: Penicillin

Atypical Pneumonia and Pontiac Fever

Atypical pneumonia commonly treated with macrolides.
Pontiac fever presents with acute flu-like symptoms.

Rickettsia

Obligate intracellular parasites, transmitted by vectors.
Diagnosis via Weil-Felix reaction.
Symptoms manifest as a triad: fever, rashes, headache.
Treatment includes Tetracycline and Chloramphenicol.

Borrelia

Primary species: Borrelia burgdorferi, transmitted by Ixodes ticks.
Associated with Lyme disease.

Microbial Growth Stages

Lag Phase: Initial adaptation stage.
Log Phase: Maximum exponential growth.
Stationary Phase: Replications equal deaths.
Death Phase: Mortality exceeds replication rates.

Bacterial Structure

Cell Membrane: Phospholipid bilayer, acts as a selective barrier, involved in ATP production.
Attachment Proteins: Fimbriae for host attachment, pili for bacterial conjugation.
Organs of Locomotion:
- Axial filaments for spirochetes.
- Flagella arrangements: atrichous, monotrichous, lophotrichous, amphitrichous, and peritrichous.

Internal Bacteria Structures

Nucleoid: Circular, double-stranded DNA; essential for genetic information.
Plasmids: Extrachromosomal DNA; carries non-essential genes like resistance (R plasmids) and virulence factors.

Gene Transfer Methods

Transformation: Uptake of naked DNA.
Transduction: Bacteriophage-mediated gene transfer.
Conjugation: Transfer via sex pili (F plasmid).
Transposition: Transfer via transposons (jumping genes).

Nutritional Requirements for Bacteria

Energy Sources: Phototrophs (light) and chemotrophs (redox reactions).
Carbon Sources:
- Heterotrophs require organic carbon.
- Autotrophs utilize inorganic carbon.
Oxygen Requirements:
- Obligate aerobes need O2 for survival.

Culture Media Types

Blood Agar Plate (BAP): For bacteria requiring high nucleic acid content.
Selective Media Example:
- MacConkey Agar (MCA) and Eosin Methylene Blue (EMB) for Enterobacteriaceae.
- Colistin-Nalidixic Agar (CAN) for Gram-positive organisms.
- Thayer-Martin for Neisseria spp.### Bacterial Infections in Different Age Groups
Infants and toddlers: Common pathogens include H. influenzae and N. meningitidis.
Teenagers and young adults: Higher incidence of S. pneumoniae.
Elderly: Increased risk of infections, including those from Gram-negative bacilli.

Otitis Media and Bacterial Epiglottitis

Otitis Media: Treated with amoxicillin.
Acute bacterial epiglottitis: Managed with 3rd generation cephalosporins like Ceftriaxone.

Haemophilus Infections

H. aegypticus: Causes purulent conjunctivitis, treated with topical sulfonamide.
H. ducreyi: Causes ulcers; treated with Azithromycin or Ceftriaxone.

Brucellosis

Zoonotic infection caused by Brucella species.
Common sources: unpasteurized dairy products, direct contact with infected animals.
Presentation includes undulant fever; treated with Tetracycline and Gentamicin.

Francisella Tularensis

Causes Tularemia (rabbit fever).
Transmitted through contact or inhalation.
Treatment includes Streptomycin.

Pasteurella Multocida

Acquired through dog or cat scratches.
Causes Pasteurellosis; treated with Penicillin.

Bordetella Pertussis

Causes Whooping cough; managed with macrolides.
Diagnosis: Bordet-Gengou media.

Shigella

Major species: S. dysenteriae, S. flexneri, S. boydii, S. sonnei.
Presentation includes dysentery; treatment may include Ciprofloxacin or Azithromycin.

Campylobacter

Species: C. jejuni; oxidase positive, comma-shaped bacilli.
Commonly found in dogs; presents with crampy abdominal pain and bloody diarrhea.

Yersinia Infections

Y. enterocolitica: Transmitted fecal-orally; causes enterocolitis, sometimes mistaken for appendicitis.
Y. pestis: Known for causing bubonic plague via bites from rats or fleas.

Pseudomonas Aeruginosa

Notable as a nosocomial pathogen; produces fruity odor.
Treatment includes antipseudomonal penicillin and cephalosporins.

Vibrio species are oxidase positive and motile, leading to gastroenteritis and cholera.
Treatment varies based on species but often involves hydration and antibiotics.

Intestinal Nematodes

Common infections: Enterobius vermicularis, Trichuris trichiura, Ascaris lumbricoides, Strongyloides stercoralis.
Diagnosis often through stool examination.

Trichinella Spiralis

Transmitted through undercooked meat.
Infection leads to myalgia and eosinophilia; diagnosed by finding larvae in muscle biopsies.

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Description

Test your knowledge on key concepts in bacterial microbiology. This quiz covers the functions of the cell membrane, movement mechanisms, growth phases, and more. Perfect for students studying microbiology or related fields.