UPSC-CMS 2017 — Microbiology

Q: Which of the following cause/causes bacterial vaginosis? 1. Gardnerella 2. Mycoplasma hominis 3. Ureaplasma urealyticum Select the correct answer using the code given below:

1, 2 and 3. ***1, 2 and 3*** - Bacterial vaginosis is a polymicrobial syndrome resulting from an imbalance in the vaginal flora, often characterized by a decrease in **Lactobacilli** and an overgrowth of various anaerobic bacteria. - **Gardnerella vaginalis** is the most commonly associated bacterium, but **Mycoplasma hominis** and **Ureaplasma urealyticum** are also frequently isolated and contribute to the pathogenesis of the condition. *1 and 3 only* - This option incorrectly excludes **Mycoplasma hominis**, which is a recognized contributor to the polymicrobial nature of bacterial vaginosis. - While *Gardnerella* and *Ureaplasma* are significant, the disease involves multiple species. *2 and 3 only* - This option incorrectly excludes **Gardnerella vaginalis**, which is considered the hallmark organism and a primary diagnostic indicator for bacterial vaginosis. - Omitting *Gardnerella* would misrepresent the key infectious agents involved. *1 only* - This option incorrectly suggests that **Gardnerella vaginalis** is the sole causative agent, overlooking the polymicrobial nature of bacterial vaginosis. - The condition is characterized by a shift in the entire vaginal microenvironment, involving multiple types of bacteria. [Practice more Microbiology PYQs on OnCourse]

Q: Tetanus spores can be effectively killed by

Gamma irradiation. ***Gamma irradiation*** - **Gamma irradiation** denatures proteins and damages nucleic acids, effectively destroying bacterial spores like those of *Clostridium tetani*. - This method is used for sterilizing heat-sensitive materials and achieving a high level of **microbial inactivation**. *Anti tetanus Serum* - **Anti-tetanus serum (ATS)** contains pre-formed antibodies that neutralize the circulating tetanus **toxin**, not the spores. - ATS is used for **passive immunization** and treatment of tetanus, but it does not kill the bacterial spores themselves. *Tetanus toxoid* - **Tetanus toxoid** is an inactivated bacterial toxin used to stimulate an immune response and provide **active immunization** against the toxin. - It does not directly kill tetanus spores; instead, it prevents the effects of the toxin produced by the spores. *Large doses of penicillin* - **Penicillin** is an antibiotic that can kill *Clostridium tetani* bacteria, but it is much less effective against the dormant and highly resistant **tetanus spores**. - While it can help eradicate active infection, spores often require more potent physical or chemical sterilization methods. [Practice more Microbiology PYQs on OnCourse]

2 Previous Year Questions with Answers & Explanations

Questions

All Subjects Anatomy (4)Anesthesiology (1)Biochemistry (1)Community Medicine (36)Dermatology (2)Internal Medicine (8)Microbiology (2)Obstetrics and Gynecology (26)Ophthalmology (2)Pathology (4)Pediatrics (1)Pharmacology (3)Physiology (2)Surgery (23)

Which of the following cause/causes bacterial vaginosis? 1. Gardnerella 2. Mycoplasma hominis 3. Ureaplasma urealyticum Select the correct answer using the code given below:

Tetanus spores can be effectively killed by

UPSC-CMS 2017 - Microbiology UPSC-CMS Practice Questions and MCQs

Question 1: Which of the following cause/causes bacterial vaginosis? 1. Gardnerella 2. Mycoplasma hominis 3. Ureaplasma urealyticum Select the correct answer using the code given below:

A. 1, 2 and 3 (Correct Answer)
B. 1 and 3 only
C. 2 and 3 only
D. 1 only

Explanation: ***1, 2 and 3*** - Bacterial vaginosis is a polymicrobial syndrome resulting from an imbalance in the vaginal flora, often characterized by a decrease in **Lactobacilli** and an overgrowth of various anaerobic bacteria. - **Gardnerella vaginalis** is the most commonly associated bacterium, but **Mycoplasma hominis** and **Ureaplasma urealyticum** are also frequently isolated and contribute to the pathogenesis of the condition. *1 and 3 only* - This option incorrectly excludes **Mycoplasma hominis**, which is a recognized contributor to the polymicrobial nature of bacterial vaginosis. - While *Gardnerella* and *Ureaplasma* are significant, the disease involves multiple species. *2 and 3 only* - This option incorrectly excludes **Gardnerella vaginalis**, which is considered the hallmark organism and a primary diagnostic indicator for bacterial vaginosis. - Omitting *Gardnerella* would misrepresent the key infectious agents involved. *1 only* - This option incorrectly suggests that **Gardnerella vaginalis** is the sole causative agent, overlooking the polymicrobial nature of bacterial vaginosis. - The condition is characterized by a shift in the entire vaginal microenvironment, involving multiple types of bacteria.

Question 2: Tetanus spores can be effectively killed by

A. Gamma irradiation (Correct Answer)
B. Anti tetanus Serum
C. Tetanus toxoid
D. Large doses of penicillin

Explanation: ***Gamma irradiation*** - **Gamma irradiation** denatures proteins and damages nucleic acids, effectively destroying bacterial spores like those of *Clostridium tetani*. - This method is used for sterilizing heat-sensitive materials and achieving a high level of **microbial inactivation**. *Anti tetanus Serum* - **Anti-tetanus serum (ATS)** contains pre-formed antibodies that neutralize the circulating tetanus **toxin**, not the spores. - ATS is used for **passive immunization** and treatment of tetanus, but it does not kill the bacterial spores themselves. *Tetanus toxoid* - **Tetanus toxoid** is an inactivated bacterial toxin used to stimulate an immune response and provide **active immunization** against the toxin. - It does not directly kill tetanus spores; instead, it prevents the effects of the toxin produced by the spores. *Large doses of penicillin* - **Penicillin** is an antibiotic that can kill *Clostridium tetani* bacteria, but it is much less effective against the dormant and highly resistant **tetanus spores**. - While it can help eradicate active infection, spores often require more potent physical or chemical sterilization methods.