Typhoid MCQs With Answer

Typhoid MCQs With Answer tailored for B. Pharm students provide a focused, exam-ready review of typhoid fever caused by Salmonella Typhi. This concise, keyword-rich introduction covers pathophysiology, clinical features, diagnostics (blood culture, Widal, PCR), pharmacotherapy (ceftriaxone, azithromycin, fluoroquinolones), antibiotic resistance, vaccines (Ty21a, Vi polysaccharide, conjugate vaccines) and prevention strategies. These MCQs emphasize therapeutics, mechanisms of action, adverse effects, pharmacokinetics, and public health implications relevant to pharmacy practice. Each question is designed to deepen conceptual understanding and clinical decision-making skills for undergraduate pharmacists. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. Which organism is the primary causative agent of classical typhoid fever?

• Salmonella enteritidis
• Salmonella typhimurium
• Salmonella Typhi
• Escherichia coli

Correct Answer: Salmonella Typhi

Q2. The most reliable method for definitive diagnosis of typhoid fever in the first week of illness is:

• Widal test
• Stool culture
• Blood culture
• Urine culture

Correct Answer: Blood culture

Q3. The Vi antigen used in typhoid vaccines is a:

• Protein antigen from bacterial flagella
• Capsular polysaccharide antigen
• Outer membrane lipoprotein antigen
• Ribosomal protein antigen

Correct Answer: Capsular polysaccharide antigen

Q4. Which clinical sign is classically associated with typhoid fever but is not universally present?

• Rose spots
• Kayser-Fleischer rings
• Photophobia
• Petechial rash on palms

Correct Answer: Rose spots

Q5. The mechanism of action of ceftriaxone in treating typhoid involves:

• Inhibition of bacterial DNA gyrase
• Inhibition of cell wall peptidoglycan cross-linking by binding PBPs
• Disruption of 30S ribosomal subunit
• Inhibition of folic acid synthesis

Correct Answer: Inhibition of cell wall peptidoglycan cross-linking by binding PBPs

Q6. A rising titre in the Widal agglutination test primarily indicates:

• Recent vaccination with Vi vaccine
• Cross-reactivity with E. coli
• Current or recent infection with Salmonella Typhi
• Carrier state in gallbladder

Correct Answer: Current or recent infection with Salmonella Typhi

Q7. Which antibiotic class has seen increasing resistance in many regions for typhoid treatment due to gyrA mutations?

• Beta-lactams
• Aminoglycosides
• Fluoroquinolones
• Macrolides

Correct Answer: Fluoroquinolones

Q8. The recommended first-line oral agent for uncomplicated typhoid in many areas with fluoroquinolone resistance is:

• Azithromycin
• Chloramphenicol
• Tetracycline
• Amikacin

Correct Answer: Azithromycin

Q9. The carrier state of Salmonella Typhi is most often associated with chronic infection of which organ?

• Kidney
• Gallbladder
• Lungs
• Pancreas

Correct Answer: Gallbladder

Q10. Which of the following complications is a surgical emergency in typhoid fever?

• Relative bradycardia
• Intestinal perforation
• Mild hepatosplenomegaly
• Low-grade anemia

Correct Answer: Intestinal perforation

Q11. Which laboratory finding is commonly seen in typhoid fever?

• Marked leukocytosis with left shift
• Leukopenia or normal white cell count
• Significant eosinophilia
• Hypergammaglobulinemia only

Correct Answer: Leukopenia or normal white cell count

Q12. Ty21a vaccine is classified as which type of vaccine?

• Inactivated whole-cell vaccine
• Live attenuated oral vaccine
• Vi polysaccharide injectable vaccine
• mRNA vaccine

Correct Answer: Live attenuated oral vaccine

Q13. Which diagnostic test remains positive longest and is considered more sensitive later in disease for typhoid?

• Blood culture
• Bone marrow culture
• Widal test
• Urine culture

Correct Answer: Bone marrow culture

Q14. The primary host adaptation that allows Salmonella Typhi to cause systemic infection involves:

• Production of enterotoxin identical to cholera toxin
• Ability to invade and survive within macrophages
• Formation of endospores for persistence
• Secretion of coagulase to form abscesses

Correct Answer: Ability to invade and survive within macrophages

Q15. Resistance to chloramphenicol in Salmonella Typhi is commonly mediated by:

• Plasmid-encoded acetyltransferases
• Mutations in 23S rRNA
• Porin loss
• Efflux pumps specific to tetracyclines

Correct Answer: Plasmid-encoded acetyltransferases

Q16. Which public health measure most effectively reduces typhoid incidence in endemic areas?

• Mass oral antiviral distribution
• Improved water sanitation and hygiene
• Universal chest X-ray screening
• Prophylactic antifungal treatment

Correct Answer: Improved water sanitation and hygiene

Q17. A key pharmacokinetic advantage of azithromycin in typhoid therapy is:

• Poor intracellular penetration
• Short tissue half-life requiring frequent dosing
• Excellent intracellular accumulation and long tissue half-life
• High renal excretion necessitating dose change in renal failure

Correct Answer: Excellent intracellular accumulation and long tissue half-life

Q18. Which serovar causes enteric fever similar to Salmonella Typhi but is often associated with milder disease—relevant for differential diagnosis?

• Salmonella Paratyphi A
• Salmonella Dublin
• Salmonella Enteritidis
• Salmonella Choleraesuis

Correct Answer: Salmonella Paratyphi A

Q19. The term “multidrug-resistant (MDR) typhoid” traditionally refers to strains resistant to:

• Fluoroquinolones, macrolides, and aminoglycosides
• Amoxicillin, chloramphenicol, and co-trimoxazole
• Ceftriaxone, azithromycin, and ciprofloxacin
• Tetracycline, vancomycin, and rifampicin

Correct Answer: Amoxicillin, chloramphenicol, and co-trimoxazole

Q20. Relative bradycardia in typhoid fever refers to:

• Heart rate higher than expected for fever
• Heart rate lower than expected for fever
• Complete heart block requiring pacemaker
• Transient atrial fibrillation episodes

Correct Answer: Heart rate lower than expected for fever

Q21. The Vi conjugate typhoid vaccine provides improved immunity in young children primarily because:

• It uses live bacteria to stimulate innate immunity
• Conjugation to a protein carrier elicits T-cell dependent response
• It contains higher antigen quantity than polysaccharide alone
• It is administered with an adjuvant that suppresses immune tolerance

Correct Answer: Conjugation to a protein carrier elicits T-cell dependent response

Q22. Which antibiotic acts by inhibiting bacterial 50S ribosomal subunit and is used orally in typhoid with intracellular activity?

• Azithromycin
• Gentamicin
• Cefixime
• Trimethoprim

Correct Answer: Azithromycin

Q23. In endemic settings, which sample yields the highest culture positivity for Salmonella Typhi after the first week of illness?

• Blood
• Bone marrow
• Stool
• Saliva

Correct Answer: Stool

Q24. A pharmacist counseling on typhoid vaccines should note that the oral Ty21a vaccine is contraindicated in:

• Healthy adults
• Immunocompromised patients
• People with a history of penicillin allergy
• Pregnant women only after first trimester

Correct Answer: Immunocompromised patients

Q25. The primary advantage of ceftriaxone over older oral agents in severe typhoid is:

• Superior oral bioavailability
• Stable activity against many MDR and fluoroquinolone-resistant strains
• Lower cost in low-resource settings
• No need for parenteral administration

Correct Answer: Stable activity against many MDR and fluoroquinolone-resistant strains

Q26. The Widal test detects antibodies against which Salmonella antigens?

• O and H antigens
• Vi and K antigens
• LPS core only
• Flagellar protein only

Correct Answer: O and H antigens

Q27. Which one of the following is a major public health reservoir facilitating typhoid transmission?

• Infected cattle herds
• Contaminated water and food handled by chronic carriers
• Airborne droplets from symptomatic patients
• Soil-borne spores

Correct Answer: Contaminated water and food handled by chronic carriers

Q28. Which lab test is most useful to detect carriers of Salmonella Typhi after clinical recovery?

• Repeated stool cultures
• Single Widal test
• Chest X-ray
• Urine antigen test

Correct Answer: Repeated stool cultures

Q29. Which of the following is an important adverse effect of chloramphenicol relevant to pharmacy practice?

• Nephrotoxicity causing acute tubular necrosis
• Aplastic anemia and bone marrow suppression
• Ototoxicity with irreversible hearing loss
• Photosensitivity reactions requiring sunscreen

Correct Answer: Aplastic anemia and bone marrow suppression

Q30. Which molecular mechanism confers high-level ciprofloxacin resistance in Salmonella Typhi?

• Inactivation by beta-lactamases
• Mutations in DNA gyrase (gyrA) and topoisomerase IV
• Ribosomal methylation at 23S rRNA
• Acetyltransferase-mediated modification

Correct Answer: Mutations in DNA gyrase (gyrA) and topoisomerase IV

Q31. In typhoid-endemic regions, which strategy can reduce selection pressure for resistant strains?

• Widespread empirical use of broad-spectrum antibiotics without testing
• Routinely prescribing combination antivirals
• Antimicrobial stewardship and culture-guided therapy
• Avoiding vaccination to maintain natural immunity

Correct Answer: Antimicrobial stewardship and culture-guided therapy

Q32. The pathognomonic “rose spots” of typhoid are characterized histologically by:

• Superficial epidermal necrosis
• Focal bacterial emboli with subepidermal infiltration
• Granulomatous inflammation with caseation
• Viral inclusion bodies in keratinocytes

Correct Answer: Focal bacterial emboli with subepidermal infiltration

Q33. Which laboratory marker is commonly elevated in severe systemic infections including typhoid and helps monitor response to therapy?

• C-reactive protein (CRP)
• Serum calcium
• Amylase
• Thyroid-stimulating hormone (TSH)

Correct Answer: C-reactive protein (CRP)

Q34. Which of the following antibiotics is primarily bacteriostatic and acts by inhibiting the 50S ribosomal subunit?

• Azithromycin
• Vancomycin
• Ciprofloxacin
• Ceftriaxone

Correct Answer: Azithromycin

Q35. In a patient with suspected typhoid and severe dehydration, the immediate pharmacy priority is:

• Start oral cefixime immediately
• Administer appropriate parenteral fluids and electrolytes
• Give antipyretics only and observe
• Start daily multivitamin supplements

Correct Answer: Administer appropriate parenteral fluids and electrolytes

Q36. Which vaccine type is known for providing mucosal immunity against typhoid?

• Vi polysaccharide injectable vaccine
• Oral live attenuated Ty21a vaccine
• mRNA-based Vi vaccine
• Inactivated whole-cell injectable vaccine only

Correct Answer: Oral live attenuated Ty21a vaccine

Q37. Bone marrow culture is recommended when blood culture is negative because:

• Bone marrow yields lower bacterial counts
• Antibiotic therapy does not affect bone marrow culture sensitivity as much as blood
• Bone marrow sampling is noninvasive
• Bone marrow contains antibodies that enhance culture growth

Correct Answer: Antibiotic therapy does not affect bone marrow culture sensitivity as much as blood

Q38. Which of the following best describes the incubation period of typhoid fever?

• Usually 1–3 days
• Usually 6–30 days, commonly 7–14 days
• Over 60 days uniformly
• Only a few hours after exposure

Correct Answer: Usually 6–30 days, commonly 7–14 days

Q39. The role of pharmacists in typhoid control includes all EXCEPT:

• Providing vaccine information and administration guidance
• Promoting rational antibiotic use and stewardship
• Ensuring safe water and sanitation infrastructure construction
• Counseling on adherence and adverse effects

Correct Answer: Ensuring safe water and sanitation infrastructure construction

Q40. Which laboratory parameter might be misleadingly normal during early typhoid infection?

• Elevated transaminases
• High platelet count
• White blood cell count
• Positive blood culture

Correct Answer: White blood cell count

Q41. Which antibiotic should be avoided in pediatric patients with musculoskeletal concerns due to risk of cartilage damage, previously used for typhoid?

• Azithromycin
• Ciprofloxacin (a fluoroquinolone)
• Ceftriaxone
• Amoxicillin

Correct Answer: Ciprofloxacin (a fluoroquinolone)

Q42. The primary reason for relapse after apparent clinical cure of typhoid is:

• Reinfection from a different pathogen
• Incomplete eradication due to intracellular persistence or carrier state
• Autoimmune cross-reactivity with host tissues
• Allergic reaction to antibiotics

Correct Answer: Incomplete eradication due to intracellular persistence or carrier state

Q43. Which feature differentiates Salmonella Paratyphi infections from Salmonella Typhi clinically or epidemiologically?

• Paratyphi strains often produce Vi antigen identical to Typhi
• Paratyphi-associated enteric fever is often clinically indistinguishable but may be milder and rising in incidence
• Paratyphi causes primarily urinary tract infections
• Paratyphi infections are always more severe with higher mortality

Correct Answer: Paratyphi-associated enteric fever is often clinically indistinguishable but may be milder and rising in incidence

Q44. For laboratory quality, which factor most reduces false-positive Widal results?

• Testing a single acute-phase serum sample only
• Comparing paired acute and convalescent sera to demonstrate rising titre
• Using stool antigen tests instead of serology
• Collecting blood cultures after starting antibiotics

Correct Answer: Comparing paired acute and convalescent sera to demonstrate rising titre

Q45. In pharmacology, which enzyme system is most likely involved in drug interactions with azithromycin?

• Major CYP3A4 inhibition leading to many interactions
• Azithromycin has minimal CYP inhibition, fewer interactions compared to erythromycin
• Strong induction of CYP2D6 causing reduced drug levels
• Complete inhibition of renal organic anion transporters

Correct Answer: Azithromycin has minimal CYP inhibition, fewer interactions compared to erythromycin

Q46. Which antimicrobial stewardship practice is most appropriate when culture shows Salmonella Typhi susceptible to ceftriaxone and azithromycin?

• Continue broad-spectrum empirical therapy indefinitely
• De-escalate to the narrowest effective agent based on clinical status and route feasibility
• Switch to prophylactic antifungal therapy
• Stop antibiotics immediately once fever subsides

Correct Answer: De-escalate to the narrowest effective agent based on clinical status and route feasibility

Q47. Which clinical laboratory feature suggests intestinal perforation in a typhoid patient?

• Sudden severe abdominal pain with free air under diaphragm on X-ray
• Gradual decrease in fever and increasing appetite
• Isolated thrombocytosis without abdominal signs
• Mild constipation resolving spontaneously

Correct Answer: Sudden severe abdominal pain with free air under diaphragm on X-ray

Q48. The Vi polysaccharide vaccine is less effective in children under two years because:

• They have excessive mucosal immunity interfering with response
• Polysaccharide antigens elicit poor T-cell independent responses in young children
• They clear polysaccharide quickly due to high metabolic rate
• Vaccine requires co-administration with live attenuated virus

Correct Answer: Polysaccharide antigens elicit poor T-cell independent responses in young children

Q49. Which of the following best describes the global trend relevant to typhoid antibiotic therapy?

• Global eradication achieved; antibiotics rarely needed
• Increasing antimicrobial resistance necessitates updated empirical guidelines and vaccine use
• All strains remain uniformly sensitive to older drugs like chloramphenicol
• Antibiotics are ineffective; only supportive care works

Correct Answer: Increasing antimicrobial resistance necessitates updated empirical guidelines and vaccine use

Q50. A B. Pharm student should emphasize which patient counseling point when dispensing azithromycin for typhoid?

• Azithromycin must not be taken with any fluids
• Complete the full course even if symptoms improve and inform about possible GI side effects
• Stop medication immediately when fever decreases
• Azithromycin always causes severe irreversible hearing loss

Correct Answer: Complete the full course even if symptoms improve and inform about possible GI side effects

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