Micro exam 3

What are narrow-spectrum antibiotics designed to target?

Specific types of bacteria, either gram-positive or gram-negative.

What is the definition of broad-spectrum antibiotics?

Antibiotics that affect a wide range of bacteria, including both gram-positive and gram-negative.

What does selective toxicity mean in the context of antibiotics?

It refers to antibiotics being more harmful to bacteria than to human cells.

What is the mechanism of action for bacitracin?

Inhibits peptidoglycan synthesis and is used topically.

How do beta-lactams work?

They inhibit cell wall synthesis by targeting penicillin-binding proteins (PBPs).

What is penicillin?

A natural beta-lactam antibiotic that is only slightly modified in some forms.

What makes cephalosporins distinct from penicillin?

Cephalosporins are modified beta-lactams that come in multiple generations with increasing gram-negative coverage.

What are carbapenems known for?

Broad-spectrum synthetic antibiotics that are highly resistant to beta-lactamases.

What type of bacteria do monobactams primarily target?

Gram-negative bacteria, and they have a single-ring structure.

What is the function of cycloserine?

It inhibits formation of the bacterial cell wall by interfering with amino acid configuration.

How does vancomycin affect bacterial cells?

It inhibits cell wall synthesis by binding to the D-Ala-D-Ala bridge in NAM subunits.

What is a key side effect of ethambutol?

Optic neuritis, which can affect color vision.

What is isoniazid used for?

It blocks mycolic acid synthesis and is used against acid-fast bacteria like TB and leprosy.

How do aminoglycosides cause bacterial death?

They cause misreading of mRNA, resulting in incorrect amino acids in protein synthesis.

What does chloramphenicol inhibit?

It inhibits peptidyl transferase, preventing peptide bond formation.

What is the action of oxazolidinones (e.g., Linezolid)?

They prevent assembly of the 70S ribosome by blocking 50S/30S subunit binding.

What is the main function of macrolides like erythromycin?

They bind to the 50S subunit and prevent translocation along mRNA.

What do tetracyclines block in bacterial cells?

They block tRNA binding to the A-site on the 30S subunit, preventing amino acid addition.

What is the role of mupirocin?

It inhibits isoleucyl-tRNA synthetase, blocking isoleucine incorporation.

How do sulfonamides affect bacteria?

They mimic PABA to block folic acid synthesis.

What type of bacteria do fluoroquinolones inhibit?

They inhibit DNA gyrase and topoisomerase IV, preventing DNA replication.

What effect do nitroimidazoles (e.g., Metronidazole) have on bacteria?

They produce free radicals in anaerobic bacteria, causing DNA damage.

What is the main function of rifampin?

It inhibits bacterial RNA polymerase, stopping transcription.

What does the Latin term 'Vacca' refer to in the context of vaccines?

It refers to cow, originating from Edward Jenner’s cowpox/smallpox experiments.

What is the primary purpose of a vaccine?

To introduce antigens to stimulate B and T cell memory without causing disease.

What are live attenuated vaccines?

Weakened forms of pathogens that can replicate but do not cause illness.

What are inactivated (killed) vaccines?

Entire pathogens killed that cannot replicate but still trigger immunity.

What are subunit vaccines?

Vaccines that contain only specific parts (antigens) of a pathogen.

What does 'conjugated vaccine' mean?

A vaccine that links polysaccharides to a protein to enhance immune response.

What is a contraindication in vaccination terms?

A medical reason not to receive a vaccine or drug, such as allergy or immunosuppression.

What is herd immunity?

When a large portion of a population is immune, it indirectly protects those who are not.

What infection is caused by Candida albicans?

Thrush, yeast infections, and cutaneous/systemic infections.

What is unique about Candida auris?

It is a multidrug-resistant fungus often acquired in hospitals.

What does Claviceps purpurea produce?

Lysergic acid, a precursor to LSD, causing ergotism.

What disease does Coccidioides immitis cause?

Valley Fever, a respiratory infection from airborne spores.

What is another name for Sporothrix schenckii infections?

Rose gardener's disease, causing nodular skin lesions.

What serious condition can Mucor spp. cause?

Mucormycosis, including rhino-cerebral infections.

What are the types of cutaneous mycoses?

Dermatophytes infections like tinea capitis (scalp), tinea barbae (beard), and others.

What does Toxoplasma gondii infect?

Found in cat feces and is dangerous during pregnancy.

What is Naegleria fowleri commonly known as?

Brain-eating amoeba, found in warm freshwater.

What are common symptoms of Enterobius vermicularis (pinworm) infection?

Itchy anus, especially at night, common in children.

What does Giardia lamblia cause?

Greasy diarrhea and flatulence, known as 'beaver fever.'

How is Loa loa transmitted?

By a fly, migrating under the skin and across the eye.