Rickettsia Multiple Choice Question & Answers

1. Drug of choice for scrub typhus is?

1. Erythromycin
2. Metronidazole
3. Sulfonamides
4. Doxycycline
5. Rickettsia

Answer. (4) (Doxycycline).

Read And Learn More: Micro Biology And Immunology Multiple Choice Question And Answers

2. Doughnut granuloma:

1. RMSF
2. fever
3. Lyme disease
4. Ehrlichiosis

Answer. (2) (fever)

Explanation: fever, though uncommon, may produce distinctive “doughnut” granulomas in the liver and bone marrow’ that may be helpful in establishing the diagnosis.

3. Scrub typhus caused by O.tsutsugamushi is transmitted by:

1. Flea
2. Chigger
3. Tick
4. Mosquito

Answer. (2) (Chigger)

Scrub typhus caused by O. tsutsugamushi is transmitted by mite (chiggers).

4. A 25-year-old boy went for trekking, came with a history of rash. Weil Felix test revealed elevated Ox 2 and Ox 19 titres. What is the most likely organism?

1. Rickettsia rickettsiae
2. Rickettsia prowazekii
3. Rickettsia typhi
4. Scrub typhus

Answer. (1) (R. rickettsiae)

Elevated Ox 2 and Ox 19 titre on Weill Felix- Suggestive of tick-borne Rickettsia infections.

5. Which are/is serologically diagnosed?

1. Typhoid
2. fever
3. Gonorrhea
4. Actinomyces
5. Scrub typhus

Answer. (1, 2, 5) (Typhoid, fever, Scrub typhus)

Serological diagnosis of antibody detection is useful both for Typhoid, fever and also scrub typhus by Weil felix and ELISA. Serology is not useful for gonorrhea and Actinomyces.

6. Which of the following statement is True?

1. Scrub typhus-Weil Felix test negative
2. Neil Mooser reaction: RMSF shows scrotal necrosis
3. Only Proteus vulgaris antigens are used in Weil Felix test

Answer. (2) (Neil Mooser reaction: RMSF shows scrotal necrosis)

7. A patient is presented with rashes all over body sparing palm and soles. He does not have h/o of animal exposure. This condition may be associated with which of the following rickettsial infection?

1. Epidemic typhus
2. fever
3. RMSF
4. Rickettsialpox

Answer. (1) (Epidemic typhus)

Distribution of rashes in rickettsial infection

8. Brill Zinsser disease- True statement is:

1. Latent period < 1 month
2. Severe form of recrudescence
3. Mild illness, for several months

Answer. (3) (Mild illness, for several months)

• It is a mild recrudescent illness occurring years after acute epidemic typhus.

9. Which is transmitted by louse?

1. Endemic typhus
2. Scrub typhus
3. Trench fever
4. fever
5. Relapsing fever

Answer. (2, 5) (Trench fever, Relapsing fever)

• Louse-borne diseases are Epidemic typhus, Epidemic Relapsing fever, Trench fever, and Pediculosis.

10. Well felix reaction for Scrub typhus shows positivity for:

1. OXK
2. OXK & OXI9
3. OX-2
4. OX-19

Answer. (1) (OXK)

• In Scrub typhus, Well Felix reaction shows a raise in OXK titer.

11. All are true about scrub typhus except:

1. Mite is vector
2. Adult mite feeds on vertebral host
3. Caused by Orientia tsutsugamushi
4. Tetracycline is DOC

Answer. (2) (Adult mite feeds on vertebral host)

• Mite is vector for scrub typhus
• Larval form of mite, e.g. chiggers feed on man, other forms of mite including adult form do not feed man.
• Scrub typhus Caused by Orientia tsutsugamushi
• Tetracycline is DOC.

12. Which of the following gives positive test with both Weil Felix) OX 2 and OX 19?

1. Spotted fever
2. Scrub typhus
3. Epidemic typhus
4. None of the above

Answer. (1) (Spotted fever)

• Weil Felix reaction:
• Antibodies to OX19: Epidemic and endemic typhus
• Antibodies to OX 2 and OX19: Rocky mountain spotted fever
• Antibodies to OX K: Scrub typhus.

13. Neil Mosser reaction or tunica reaction is useful to differentiate between:

1. R. prowazekii and R. typhi
2. R. typhi and R. rickettsii
3. R. prowazekii and R. rickettssii
4. R. rickettsia and C. burnetti

Answer. (1) (R. prowazekii and R. rickettssii)

• Neilmooser reaction is done to differentiate epidemic typhus R. prowazekii which gives a negative tunica reaction and endemic typhus (R. typhi) which gives a positive tunica reaction.

14. fever is caused by:

1. Rickettsia typhi
2. Coxiella burnettii
3. Salmonella
4. Escherichia coli

Answer. (2) (Coxiella burnetii)

• fever is caused by Coxiella burnetii.

15. Mite is a vector for:

1. R. typhi
2. R. prowazeki
3. R. rickettsii
4. R. tsutsugamushi
5. R. conori

Answer. (4) (R. tsutsugamushi)

• Mite transmits: Rickettsial Pox and Scrub Typhus
• Agent for Rickettsial Pox: R. akari
• Agent for Scrub Typhus: Orientia tsutsugamushi (old name- R. tsutsugamushi)

16. Scrub typhus transmitted by:

1. Reduviid bug
2. Trombiculid mite
3. Enteric pathogens
4. Cyclops

Answer. (2) (Trom…)

• Rickettsial Pox: Vector is gamasid mite
• Scrub Typhus: Vector is Trombiculid mite

17. An army jawan posted in remote forest area following a tick bite had fever andb headache. His fever was 104 °F and pulse was 70 per min. He had an erythematous lesion of about 1 cm on the leg surrounded by small vesicles, along with generalized lymphadenopathy at the time of presentation to the referral hospital. His blood sample was collected to perform serology for the diagnosis of Rickettsial disease. Which one of the following results in Weil-felix reaction will be diagnostic in this clinical setting?

1. High OX -2
2. High OX -19
3. High OX – K
4. High OX – 19 and OX – 2

Answer. (4) (High OX – 19 and OX – 2)

• History states: Tick bite followed by development of fever, headache, erythematous lesion surrounded by small vesicles, and lymphadenopathy…………… It is a case of African tick Typhus
• Vesicular rash seen in Rickettsial Pox and African tick Typhus
• Rickettsial Pox Weil Felix reaction is –ve
• In African tick Typhus Weil Felix reaction shows High OX-19 and OX2
• Weil Felix is negative for fever, R. pox, Ehrlichia, Bartonella.

18. The following is the etiological agent of Rocky mountain spotted fever:

1. Rickettsia rickettsii
2. Rochalimaea quintana
3. Rickettsia tsutsugamushi
4. Coxiella burnetii

Answer. (1) (Rickettsia rickettsii)

• Already explained.

19. All of the following statement are true regarding fever except:

1. It is zoonotic disease
2. Human disease is characterized by an interstitial pneumonia
3. No rash is seen
4. Weil–Felix reaction is very useful for diagnosis

Answer. (4) (Weil–Felix reaction is very useful for diagnosis)

Weil-Felix reaction is not useful for fever, R.pox, Ehrlichia, Bartonella.

20. Not true about scrub typhus:

1. Chigger-borne
2. Vector is mite
3. Caused by Orientiatsut sugamushi
4. Chlamydial disease
5. Has 3 serotypes

Answer. (4) (Chlamydial disease)

• Scrub typhus is rickettsial disease, caused by Orientiatsutsugamushi which has three major antigenic types: Karp, Gilliam, and Kato.
• Scrub typhus is transmitted by larval form of trombiculid mite called chiggers.

21. Which is obligate intracellular?

1. Coxiella burnetti
2. Ehrlichia chaffeensis
3. Bartonella henselae
4. Tropheryma whippelii

Answer. (2) (Ehrlichia chaffeensis)

• Ehrlichioses are obligately intracellular organisms comprised by four genera: Ehrlichia,Anaplasma, Wolbachia, and Neorickettsia.’
• The location of bacterial rRNA in tissues from patients with Whipple’s disease provides evidence that bacteria are growing outside cells and suggests that T. whippelii is not an obligate intracellular pathogen.
• Bartonella species are fastidious, facultative intracellular, slow-growing, gram-negative bacteria.
• Though rickettsiae are obligately intracellular gram-negative coccobacilli, Coxiella burnetii Rickettsia prowazekii, and R. typhi have the well-documented ability to survive for an extended period outside the reservoir or vector.

22. Morula in RBC seen in:

1. Babesia
2. Ehrlichia
3. Spirochete
4. Bartonellosis

Answer. (2) (Ehrlichia)

23. Stellate granuloma with necrotic debris and neutrophils is seen in:

1. Crohn’s disease
2. Syphilis
3. Sarcoidosis
4. Cat-scratch disease

Answer. (4) (Cat-scratch disease)

• Cat-scratch disease (agent- Bartonella henselae) involves lymph nodes that shows
• Lymphadenitis with irregular areas of necrosis surrounded by neutrophils (early stage) and palisading histiocytes in late stage (stellate granulomas)
• Axillary lymph nodes are the most frequent sites of involvement.
• A history of exposure to cats is found in almost all cases.

24. Bacillary angiomatosis is caused by:

1. Borrelia
2. Bartonella henselae
3. Rickettsia
4. Bartonella bacilliformis

Answer. (2) (B. henselae)

• Bacillary angiomatosis is an angiovascular disorder seen in HIV patients; caused by
• Bartonella henselae and Bartonella quintana.
• Skin lesions are caused by both species. Hepatosplenic lesions are caused by B. henselae; whereas lytic bony lesions are common with B. quintana.

25. Drug of choice for Bacillary angiomatosis:

1. Macrolides
2. Aminoglycosides
3. Cephalosporins
4. Carbapenems

Answer. (1) (Macrolides)

• DOC for Bacillary angiomatosis is erythromycin or doxycycline.

26. All are true about B. quintana except:

1. Causes trench fever
2. Not detected by Weil felix reaction
3. Recurrence is common
4. Tick is the vector

Answer. (4) (Tick is the vector)

• Vector for B. quintana- Louse
• Trench Fever is often periodic and recurrent, caused by B. quintana

27. Bacillary Angiomatosis occur due to:

1. Mycoplasma
2. Gardenella
3. Bartonella bacilliformis
4. Hemophilus influenzae
5. No relation with any above mentioned

Answer. (5) (No relation with any above mentioned)

• Bacillary angiomatosis is a disease of severely immunocompromised patients, is caused by B. henselae or B. quintana.
• Characterized by neovascular proliferative lesions of skin and other organiser.

28. Ehrlichia chaffeensis is causative agent of:

1. HME
2. HGE
3. Glandular fever
4. None

Answer. (1) (HME)

29. Verruga peruana caused by:

1. Bartonellabacilliformis
2. Bartonellaquintana
3. Bartonellahensale

Answer. (1) (B. bacilliformis)

• VerrugaPeruana or Peruvian Wart is caused by Bartonella baciliformis, characterized by cutaneous rashes produced by a proliferation of endothelial cells.

30. Oroya fever is caused by:

1. Bartonellahenselae
2. b. Bartonellabaciliformis
3. c. Bartonellaquintana

Answer. (2) (B. bacilliformis)

• Bartonella baciliformis causes Oroya fever or Carrion’s disease.

31. Incubation period of LGV is?

1. 3–7 days
2. 7–10 days
3. 10–30 days
4. 30–90 days

Answer. (3) (10-30 days)

32. What is the most serious cause of conjunctivitis that causes blindness in children?

1. Staphylococcus
2. Streptococcus
3. N. gonorrhea
4. Chlamydia

Answer. (4) (Chlamydia) Trachoma caused by C. trachomatis serovars A,B, Ba and C, still continues to be a leading cause of preventable infectious blindness worldwide.

33. Most common cause of neonatal eye infection:

1. Staphylococcus
2. Streptococcus
3. N. gonorrhoeae
4. Chlamydia

Answer. (4) (Chlamydia) C. trachomatis is more common cause of ophthalmia neonatorum than gonococcus.

Incubation period is longer for chlamydial infection (6–21 days) and discharge is mucopurulent compared to gonococcus (48 hours incubation period, purulent and crusted discharge).

34. Lymphogranuloma venerum is caused by which of the following sexually transmitted agent

1. H. ducreyi
2. Chlamydia trachomatis
3. Treponema pallidum
4. Calymmatobacterium

Answer. (2) (Chlamydia trachomatis)

Chlamydia trachomatis is the agent of Lymphogranuloma venereum

35. Which one of the following is implicated in the etiology of Fitz-Hugh-Curtis syndrome?

1. Chlamydial infection
2. Gastric perforation
3. Perforation of dermoid cyst
4. Liver metastases in ovarian cancer

Answer. (1) (Chlamydial infection)

Fitz–Hugh–Curtis syndrome (perihepatitis) is a complication seen in Chlamydial and gonococcal infections.

36. True about chlamydia are all except:

1. Obligate intracellular organism
2. Gram-positive
3. Reticulate body is metabolically active
4. Replicated by biniary fission

Answer. (2) (Gram-positive)

Chlamydia is poorly gram-negative.

37. Inclusion body present in psittacosis is called:

1. HP body
2. Miyagawa corpuscles
3. Levinthal cole Lillie

Answer. (3) (Levinthal cole Lillie)

38. In a patient with urethral syndrome, urine microscopy shows full of polymorph, but no bacteria. The most appropriate culture medium is:

1. McCoy cell
2. Thayer martin
3. Cooked meat
4. PPLO broth

Answer. (1) (McCoy cell)

• Chlamydia trachomatis is by far the most common cause of Urethral syndrome. So 1st attempt should be made for the isolation of Chlamydia trachomatis.
• McCoy and HeLa cell lines are used for the isolation of Chlamydia trachomatis.

Among the options:

• McCoy cell: Cell line used for Chlamydia
• Thayer martin: Culture media used for Gonococcus
• Cooked meat: Culture media used for anaerobic culture
• PPLO broth: Culture media used for Mycoplasma

39. Chlamydia escape killing by:

1. Causes cell membrane perforation
2. Produces factors that Camouflage it
3. Molecular mimicry
4. Inhibit phagolysosome fusion

Answer. (4) (Inhibit…)

• The Elementary Body is the infective form that enters the cell by receptor-mediated endocytosis and resides in an inclusion, where the entire growth cycle is completed.
• Chlamydiae prevent phagosome-lysosome fusion by which it can survive in the intracellular environment.

40. Which of the following is true about Chlamydia trachomatis?

1. It is usually symptomatic
2. It is routinely treated with penicillin
3. It is diagnosed by culture of cervical purulent discharge
4. Women using oral pills are more prone for infection

Answer. (4) (Women using oral pills are more prone for infection)

• ‘Use of oral contraceptive pills and the presence of cervical ectopy also confer an increased risk of chlamydial infection.‘

About Other Options:

• Chlamydial infections are usually asymptomatic.
• ‘The proportion of infections that are asymptomatic appears to be higher for C.
• Trachomatis than for N. gonorrhoeae, and symptomatic C. Trachomatis infections are clinically less severe’.
• It is routinely treated with Single dose Azithromycin
• It is diagnosed by isolation in McCoy and HeLa cell line. But they vary in their infectivity to cell lines.

41. Chlamydia psittacosis all are true except:

1. Acquired from bird’s droppings
2. Causes urethritis
3. Causes pneumonia
4. Treatment is tetracycline

Answer. (2) (Causes pneumonia)

• Urethritis does not occur in psittacosis
• Clinical feature of Psittacosis

42. Triad of Reiter’s syndrome:

1. Conjunctivitis
2. Uveitis
3. Mucosal lesions
4. Glaucoma

Answer. (1, 3) (Conjunctivitis, Mucosal lesions)

• Reiter’s syndrome: Consists of conjunctivitis, urethritis (or, in female, cervicitis), arthritis, and characteristic Mucocutaneous lesions in HLA-B27 phenotype patients C. trachomatis: MC case, Others Salmonella, Shigella, or Campylobacter

43. Chlamydia trachomatis false is:

1. Elementary body is metabolically active
2. It is biphasic
3. Reticulate body divides by binary fission
4. Inside the cell, it evades phagolysosome fusion

Answer. (1) (Elementary body is metabolically active)

• Chlamydia biphasic elementary and reticulate body
• Elementary body is extracellular, infectious form
• Reticulate body is the replicating form, divides by binary fission and it is metabolically active
• Chlamydia evades phagolysosome fusion, hence can survive intracellularly.

44. Which one of the following statements is true regarding Chlamydia pneumoniae?

1. Fifteen serovars have been identified as human pathogens
2. Mode of transmission is by the airborne bird excreta
3. The Cytoplasmic inclusions present in the sputum specimen are rich in glycogen
4. The group-specific antigen is responsible for the production of complement-fixing antibodies

Answer. (4) (The group-specific antigen is responsible for the production of complement-fixing antibodies)

45. The following is not a method of isolation of Chlamydia from clinical specimens:

1. Yolk sac inoculation
2. Enzyme immunoassay
3. Tissue culture using irradiated McCoy cells
4. Tissue culture using irradiated BHK cells

Answer. (2) (Enzyme immunoassay)

• Enzyme immunoassay detects either antigen or antibody (Does not help in isolation)
• Cultivation of Chlamydia:
• Not cultivable in artificial media
• Mice inoculation (infective by only C.Psittaci and LGV)
• Yolk sac, cell culture (McCoy Cells and HeLa) useful for LGV and C.Psittaci
• Pretreatment with irradiation, cycloheximide, DEAE dextran, centrifugation – enhance detection
• Hep2 for C.Pneumoniae

46. Frie test is used for:

1. LGV
2. Syphilis
3. Gonorrhea
4. Chancroid

Answer. (1) (LGV)

• Frei’s test (an intradermal test), using crude chlamydial antigen from bubo pus was previously used for detection of LGV.

47. A 32-year female is presented with vaginal discharge resembling chlamydial urethritis.Most sensitive test for diagnosing this condition is:

1. Nucleic acid amplification test
2. Gram stain
3. Culture on McCoy’s cell line
4. Serum antibody detection by MIF

Answer. (1) (Nucleic acid amplification test)

• Nucleic Acid Amplification Test (NAAT) has revolutionized the diagnosis of chlamydial infections.
• Advantage: It is highly sensitive and specific, takes less time, and detects even few copies of DNA from the sample. It can also differentiate the species and serovars.
• NAATs are currently the diagnostic assays of choice for chlamydial infection as recommended by the CDC, replacing the so called gold standard culture methods.

48. DOC of Chlamydia in pregnancy?

1. Tetracycline
2. Doxycycline
3. Amoxycillin
4. Metronidazole

Answer. (3) (Amoxycillin)

• Treatment of genital Chlamydiasis: Single dose azithromycin regimen is DOC.
• Treatment of Chlamydia in pregnancy:
• Although not approved by the FDA for use in pregnancy, single-dose regimen of azithromycin regimen appears to be safe and effective for this purpose.
• However, amoxycillin (500 mg three times daily for 7 days) can also be given to pregnant women.
• The fluoroquinolones are contraindicated in pregnancy.

49. Which of the Chlamydia species is having one serotype:

1. Chlamydia psittacosis
2. Chlamydia trachomatis
3. Chlamydia pneumophilla
4. All of the above

Mycoplasma

Answer. (3) (Chlamydia..)

Chlamydia pneumoniae has one serotype, C.trachomatis has 15 serotype and C.psittaccii has many serotypes.

50. Pathology of Mycoplasma pneumoniae is located in:

1. Interstitium
2. Intra-alveolar

Answer. (1) (Interstitium) Ref: Apurba Sastry’s Essentials of Medical Microbiology 1st/p406, 2/e p422

51. Mycoplasma is intrinsically resistant to:

1. Ceftriaxone
2. Doxycycline
3. Azithromycin
4. Levofloxacin

Answer. (1) (Ceftriaxone)

Mycoplasma is intrinsically resistant to cell wall-acting agents as it doesn’t have a true cell wall.

52. Diene’s method is used for:

1. Mycoplasma
2. Chlamydiae
3. Plague
4. Diphtheria

Answer. (1) (Mycoplasma)

Dienes method is used to stain mycoplasma.

53. Ureaplasma is naturally resistant to:

1. Erythromycin
2. Chloramphenicol
3. Cephalosporins
4. Tetracyclines

Answer. (3) (Cephalosporins)

As there is lack of peptidoglycan layer, hence Ureoplasma is naturally resistant to all beta lactams.

54. Urethral smear from a 30-year-old male is cultured and the following colonies are grown. Identify the agent?

1. Mycoplasma
2. Chlamydia
3. Mobilincus
4. Trichomonas

Answer. (1) (Mycoplasma)

• Clue for diagnosis:
• Case of urethritis, fried egg colonies on culture.

55. Which is Eaton agent?

1. Mycoplasma
2. H. influenzae
3. Klebsiella
4. Chlamydia pneumoniae

Answer. (1) (Mycoplasma)

Eaton had isolated Mycoplasma pneumoniae from hamsters and cotton rats. As it was filterable, so it was 1st considered as virus as ‘Eaton agent‘.

56. In reference to the Mycoplasma, the following are true except:

1. They are inhibited by penicillin
2. They can reproduce in cell-free media
3. They have an affinity for mammalian cell membranes
4. They can pass through filters of 450 nm pore size

Answer. (1) (They are inhibited by penicillin)

About Other Options

• Mycoplasma is completely resistant to penicillin because they lack the cell wall structures at which penicillin acts, but they are inhibited by tetracycline or erythromycin.
• Mycoplasma have an affinity for mammalian cell membranes
• Filterable, can pass through filters of 450 nm pore size
• Mycoplasma can reproduce in cell-free media; on agar, the center of the whole colony is characteristically embedded beneath the surface.

57. DOC for Mycoplasma pneumoniae: 

1. Azithromycin
2. Amoxiclav
3. Doxycycline
4. Amikacin

Answer. (1) (Azithromycin)

• Macrolides are drug of choice (oral azithromycin) for Mycoplasma infections.