Question 1

Small gram negative cocci, occur in pairs

Accepted Answer

Answer reason: Neisseria species are classically described as gram-negative diplococci, meaning they appear as small cocci occurring in pairs on Gram stain. In contrast, Staphylococcus are gram-positive cocci in clusters and Streptococcus are gram-positive cocci in chains or pairs. The stem’s morphology and Gram reaction most specifically match Neisseria.
Category reason: This question tests identification of bacteria based on Gram stain characteristics and cellular arrangement, which is a core concept in Microbiology rather than patient-care decision-making.

Question 2

Transfer of genetic information from one bacterium to another by bacteriophages is called?

Accepted Answer

Answer reason: b. Transduction Bacteriophages can accidentally package bacterial DNA and deliver it into another bacterial cell, enabling horizontal gene transfer. This phage-mediated transfer is specifically termed transduction. Transformation instead involves uptake of naked DNA from the environment, while conjugation requires direct cell-to-cell contact via a pilus. Mutation refers to changes in an organism’s DNA sequence rather than transfer between bacteria.
Category reason: This question tests a foundational microbiology concept of horizontal gene transfer mechanisms (phage-mediated DNA transfer), not a nursing intervention or clinical judgment scenario.

Question 3

Salmonella are?

Accepted Answer

Answer reason: Salmonella are Enterobacteriaceae that can generate energy via aerobic respiration when oxygen is available and switch to anaerobic metabolism (e.g., fermentation) when it is not. This ability allows growth in diverse environments including the gastrointestinal tract. They are not obligate aerobes, obligate anaerobes, or microaerophiles, which each have more restricted oxygen requirements.
Category reason: This question tests bacterial oxygen-growth classification, a core concept in microbiology rather than nursing care decision-making.

Question 4

According to pH, vibrio cholera is?

Accepted Answer

Answer reason: It grows best in alkaline conditions (higher pH). This aligns with its ability to thrive in environments such as the small intestine and alkaline aquatic habitats. In contrast, acidophiles prefer low pH and neutrophiles prefer near-neutral pH, while osmophiles are defined by high sugar/osmotic environments rather than pH.
Category reason: This question tests classification of a bacterium by preferred environmental pH, which is a foundational organism characteristic studied in Microbiology.

Question 5

Staphylococcus are?

Accepted Answer

Answer reason: Staphylococci are non-motile and do not possess flagella, so they are classified as lacking flagella. The other choices describe specific arrangements of one or multiple flagella (mono-, amphi-, peri-trichous), which apply to motile bacteria. In contrast, motility in bacteria is most commonly mediated by flagella; absence of these structures corresponds to the atrichous category. Therefore, the best match for staphylococci is the flagella-absent classification.
Category reason: This question tests bacterial structural classification based on presence and arrangement of flagella, which is a core concept in Microbiology.

Question 6

The spread of Pyogenic Bacteria in blood stream to different organs & produce multiple abscess is?

Accepted Answer

Answer reason: d- Pyaemia Pyaemia refers to dissemination of pyogenic organisms via the bloodstream with septic emboli that seed multiple organs and form metastatic abscesses. Bacteremia is the presence of bacteria in blood without necessarily causing abscess formation. Septicemia implies systemic illness due to infection in the bloodstream, but the defining feature of multiple secondary abscesses is specifically associated with pyaemia. Toxemia is circulation of bacterial toxins rather than the organisms causing metastatic suppuration.
Category reason: This tests definitions of bloodstream infection syndromes and metastatic abscess formation by pyogenic bacteria, which is core Microbiology terminology and concepts rather than nursing interventions.

Question 7

To sterilize fluid damaged by heat:

Accepted Answer

Answer reason: Heat-labile fluids (e.g., many protein solutions) can be sterilized by physically removing microorganisms rather than exposing them to damaging temperatures. Membrane filtration (commonly 0.22 μm) effectively removes bacteria and many fungi while preserving the chemical stability of the fluid. Heat-based methods would degrade the product, and gaseous or radiation methods are generally used for devices/materials and may not be appropriate for many liquids.
Category reason: This question tests principles of sterilization methods for microorganisms, which is a core topic in Microbiology rather than nursing care decision-making.

Question 8

For water disinfection we use:

Accepted Answer

Answer reason: It is the standard, widely used agent for potable water disinfection because it is effective against many waterborne bacteria and viruses and can provide residual protection in distribution systems. It is practical, inexpensive, and has well-established dosing/monitoring protocols (e.g., free residual chlorine). The other agents listed are primarily used for surface or equipment disinfection/antisepsis and are not typical choices for routine municipal or household drinking-water disinfection due to toxicity, instability, or limited applicability.
Category reason: This question tests knowledge of common disinfectants used for water treatment, which is primarily a microbiology/infection control science concept rather than a nursing care decision.

Question 9

Which of the following is used for case detection of leprosy?

Accepted Answer

Answer reason: B. Skin slit smear Skin smear microscopy is used to demonstrate acid-fast bacilli and helps identify active multibacillary disease, making it useful for confirming and classifying cases found in screening. The lepromin test assesses cell-mediated immunity and is not used for diagnosis or case detection. VDRL is a syphilis screening test, and a nonspecific blood test does not reliably detect leprosy.
Category reason: This question tests diagnostic identification of an infectious disease organism and the appropriate test to detect it, which is primarily taught in Microbiology rather than nursing care decision-making.

Question 10

The National Vector Borne Disease Control Programme (NVBDCP) covers all of the following EXCEPT:

Accepted Answer

Answer reason: NVBDCP targets vector-borne diseases transmitted by mosquitoes or other arthropods, including malaria, dengue, and Japanese encephalitis. Typhoid fever is primarily a water/food-borne infection caused by Salmonella Typhi and is not transmitted via insect vectors. Therefore it is not included under vector-borne disease control programmes focused on vector control and related surveillance.
Category reason: This question tests classification of communicable diseases by mode of transmission and which are included in a vector-borne control program, which is a core Microbiology/public health concept rather than a bedside nursing intervention decision.

Question 11

. in viral replication which is true?

Accepted Answer

Answer reason: Viral replication generally proceeds through attachment, penetration/entry, uncoating, biosynthesis (genome replication and protein synthesis), assembly/maturation, and finally release from the host cell. Penetration is not the first step because attachment occurs before entry. Assembly precedes release; virions must be assembled/matured prior to being released by budding or cell lysis. Therefore, only the statement about release being the last step is consistently true.
Category reason: This question tests the sequence of steps in viral replication, which is a core concept in microbiology rather than a nursing care decision or prioritization task.

Question 12

Aseptic technique prevents:

Accepted Answer

Answer reason: Aseptic technique aims to prevent the introduction and transmission of microorganisms during procedures by maintaining sterility and reducing contamination. This directly lowers the risk of pathogen entry into normally sterile sites and subsequent disease. Pain, fever, and vomiting may occur for many reasons and are not specifically prevented by sterile technique. Therefore, the primary preventive target is infectious complications.
Category reason: This question tests understanding of how sterile/aseptic practices reduce microbial contamination and transmission, which is core to Microbiology rather than a patient-care decision pathway.

Question 13

Which virus causes AIDS?

Accepted Answer

Answer reason: AIDS is the advanced clinical syndrome caused by chronic infection that progressively damages CD4+ T lymphocytes, leading to severe immunodeficiency. The causative agent is HIV, a retrovirus that integrates into host DNA and impairs immune function over time. Hepatitis B primarily targets the liver, influenza causes acute respiratory illness, and rotavirus causes gastroenteritis, none of which produce the characteristic progressive immune collapse of AIDS.
Category reason: This question tests identification of the infectious agent responsible for a disease, which is a core Microbiology concept rather than a nursing intervention or care-prioritization scenario.

Question 14

Commonest complication of mumps is?

Accepted Answer

Answer reason: Mumps virus commonly causes CNS involvement, and the most frequent neurologic complication is aseptic meningitis, often presenting with headache, neck stiffness, and CSF lymphocytic pleocytosis. Encephalitis can occur but is less common and typically more severe. Pancreatitis is a recognized complication but occurs less frequently than aseptic meningitis. Pneumonia is not the typical common complication associated with mumps compared with CNS manifestations.
Category reason: This is testing complications of a viral infectious disease (mumps) and its pathogenesis/clinical sequelae, which falls under Microbiology rather than nursing care prioritization.

Question 15

Tuberculosis Spread through:

Accepted Answer

Answer reason: Tuberculosis is transmitted primarily via inhalation of airborne droplet nuclei expelled when an infected person coughs, sneezes, sings, or talks. These particles can remain suspended and be inhaled by others, especially in enclosed, poorly ventilated spaces. It is not spread by mosquitoes, and it is not a waterborne infection under typical transmission patterns.
Category reason: This question tests the mode of transmission of an infectious disease, which is a core topic in Microbiology.

Question 16

In the cerebrospinal fluid (CSF) analysis of a person with meningitis, which of the following findings would point to syphilitic meningitis?

Accepted Answer

Answer reason: Syphilitic (neurosyphilis) meningitis is a form of chronic meningitis and typically shows a lymphocytic (not neutrophilic) pleocytosis in CSF rather than neutrophil predominance. CSF glucose is often normal or only mildly reduced in spirochetal/chronic meningitides, contrasting with the more marked hypoglycorrhachia seen in acute pyogenic bacterial meningitis. Therefore, a pattern without neutrophils and with normal glucose is most consistent with syphilitic meningitis among the choices.
Category reason: This item tests organism-related CSF patterns in meningitis (cell type and glucose profile) to identify syphilis as an infectious etiology, which is primarily microbiology/infectious disease knowledge rather than a nursing intervention or prioritization task.

Question 17

Who discovered tuberculin skin test?

Accepted Answer

Answer reason: This is a historical microbiology/immunology fact about tuberculosis screening. Von Pirquet introduced the cutaneous tuberculin reaction (Pirquet test), an early form of tuberculin skin testing based on delayed-type hypersensitivity. The other options are associated with different landmark discoveries (Pasteur with germ theory/vaccines, Ross with malaria transmission, Jenner with smallpox vaccination).
Category reason: This question tests foundational knowledge about tuberculosis diagnostic testing history, which is most directly aligned with Microbiology rather than nursing care prioritization or interventions.

Question 18

IF A DISEASE JUMPS FROM A NON-HUMAN ANIMAL TO A HUMAN, THEN IT IS TERMED AS?

Accepted Answer

Answer reason: Zoonoses are infections naturally transmitted between vertebrate animals and humans (e.g., rabies, avian influenza, brucellosis). “Infectious disease” is too broad and does not specify animal-to-human transmission. “Congenital” refers to conditions present at birth, and “iatrogenic” refers to illness caused by medical care or procedures.
Category reason: This item tests a foundational definition about modes of transmission and disease terminology, which is core content in Microbiology rather than nursing judgment or patient-care prioritization.

Question 19

ASO test is used to detect bacterial infection?

Accepted Answer

Answer reason: ASO (antistreptolysin O) measures antibodies produced against streptolysin O, a toxin made by Group A beta-hemolytic streptococci. A raised titer supports recent streptococcal infection and is classically used in evaluating post-streptococcal complications such as rheumatic fever and post-streptococcal glomerulonephritis. It is not a marker for staphylococcal, pneumococcal, or salmonella infections, and titers may be low in some streptococcal skin infections.
Category reason: This question tests knowledge of a specific serologic marker (ASO) and its association with a bacterial genus, which is primarily microbiology/immunologic identification rather than a nursing intervention or patient-care decision.

Question 20

What is the primary mode of transmission of dengue fever?

Accepted Answer

Answer reason: Dengue virus is an arbovirus transmitted primarily by Aedes mosquitoes (especially Aedes aegypti and Aedes albopictus), which bite during daytime hours. The mosquito acquires the virus by feeding on a viremic human and then transmits it to another person during subsequent bites. It is not typically spread via contaminated water, airborne droplets, or routine direct person-to-person contact.
Category reason: This question tests the infectious disease transmission vector and epidemiology of dengue virus, which is a microbiology concept rather than a nursing intervention or prioritization scenario.

Question 21

Which of the following Hepatitis virus is Transmitted by the Fecal_Oral route ?

Accepted Answer

Answer reason: Hepatitis A is classically transmitted via the fecal–oral route, commonly through contaminated food or water and close person-to-person contact in settings with poor sanitation. In contrast, hepatitis B is primarily spread via blood and body fluids (sexual contact, perinatal, needles), hepatitis C mainly through blood exposure, and hepatitis D requires hepatitis B co-infection and follows similar parenteral/sexual transmission patterns. Therefore, among the listed viruses, hepatitis A is the one associated with fecal–oral transmission.
Category reason: This item tests modes of transmission of viral pathogens (hepatitis viruses), which is a core concept in microbiology/infectious disease rather than a nursing intervention or prioritization scenario.

Question 22

Rabies is caused by a virus called?

Accepted Answer

Answer reason: Rabies is caused by rabies virus, a member of the genus Lyssavirus (family Rhabdoviridae), classically described as Lyssavirus type 1. It is a neurotropic, enveloped, negative-sense single-stranded RNA virus transmitted mainly through the saliva of infected animals via bites. The other options are incorrect: filarial refers to helminth parasites, myxoviruses include influenza/parainfluenza viruses, and adenoviruses typically cause respiratory, conjunctival, or gastrointestinal infections.
Category reason: This is a question about identifying the causative viral agent of an infectious disease, which is primarily studied under Microbiology rather than nursing care decision-making.

Question 23

Which of the following is a Gram-positive bacterium?

Accepted Answer

Answer reason: It is a classic Gram-positive coccus that appears in clusters due to division in multiple planes and has a thick peptidoglycan cell wall that retains crystal violet. In contrast, Escherichia coli and Klebsiella pneumoniae are Gram-negative bacilli, and Neisseria gonorrhoeae is a Gram-negative diplococcus. Differentiating Gram status is key for predicting likely antibiotic susceptibility patterns and initial empiric therapy choices.
Category reason: This question tests classification of bacteria by Gram stain characteristics, which is a foundational concept in Microbiology rather than a nursing intervention or prioritization scenario.

Question 24

A patient suffers from an acute pharyngitis and a few weeks later develops an acute-onset asymmetric chorea. You suspect she has Sydenham's chorea. Which of the following is the most likely culprit?

Accepted Answer

Answer reason: Sydenham chorea is a delayed neurologic manifestation of acute rheumatic fever that occurs weeks after untreated Group A streptococcal pharyngitis. The pathogenesis is molecular mimicry, where antibodies generated against streptococcal antigens cross-react with basal ganglia tissues, producing choreiform movements. Streptococcus agalactiae is Group B strep (classically neonatal sepsis/meningitis), and Staphylococcus aureus is not associated with post-streptococcal rheumatic fever syndromes.
Category reason: This question tests identification of the infectious organism responsible for a post-infectious sequela (Sydenham chorea after strep pharyngitis), which is primarily microbiology knowledge rather than a nursing intervention or prioritization task.

Question 25

Which staining technique is used to differentiate between Gram-positive and Gram-negative bacteria?

Accepted Answer

Answer reason: This test distinguishes organisms based on differences in cell wall structure, especially the thickness of the peptidoglycan layer and presence of an outer membrane. Gram-positive organisms retain the crystal violet–iodine complex after decolorization and appear purple, while Gram-negative organisms are decolorized and take up the counterstain (typically safranin) to appear pink/red. Ziehl-Neelsen/acid-fast staining is primarily for mycobacteria, and endospore staining is used to detect spores in genera like Bacillus and Clostridium.
Category reason: This question tests foundational laboratory identification of bacteria by staining characteristics, which is a core topic in microbiology rather than nursing care decision-making.

Question 26

Lipoarabinomannan (LAM), a diagnostic biomarker used in urine-based tests, is primarily associated with which of following bacteria?

Accepted Answer

Answer reason: LAM is a glycolipid component of the mycobacterial cell wall (part of lipoarabinomannan in the mycobacterial envelope). In active tuberculosis, especially with high mycobacterial burden (e.g., advanced HIV), LAM can be released into blood and filtered into urine, enabling urine-based antigen detection tests. The other listed organisms do not have LAM as a characteristic cell-wall antigen used for this diagnostic purpose.
Category reason: This item tests identification of a bacterial cell-wall antigen and its linkage to a specific pathogen and diagnostic test target, which is a core Microbiology concept rather than a nursing care decision.

Question 27

Tuberculosis is caused by which type of bacteria?

Accepted Answer

Answer reason: Tuberculosis is an infectious disease specifically caused by an acid-fast bacillus in the Mycobacterium genus. The organism has a lipid-rich cell wall (mycolic acids), which contributes to acid-fast staining and survival within macrophages. The other options are common bacteria that can cause different infections (e.g., pneumonia, UTIs, skin infections) but do not cause TB.
Category reason: This question tests identification of the causative bacterial organism of a specific infectious disease, which is core Microbiology knowledge rather than a nursing intervention or prioritization task.

Question 28

Which of the following organisms shows the Kanagawa phenomenon on Wagatsuma agar?

Accepted Answer

Answer reason: This phenomenon refers to beta-hemolysis on high-salt Wagatsuma blood agar due to production of thermostable direct hemolysin (TDH), a key virulence marker for pathogenic strains. It is classically associated with seafood-associated gastroenteritis caused by this organism. The other listed bacteria are not identified by a Kanagawa reaction on Wagatsuma agar.
Category reason: This question tests identification of a bacterium using a specific culture medium/phenotypic laboratory phenomenon, which is a core topic in Microbiology.

Question 29

Q.1492: Ringworm (Tinea corporis) is caused by—?

Accepted Answer

Answer reason: Tinea corporis (ringworm) is a dermatophyte infection, most commonly caused by species in the genera Trichophyton, Microsporum, or Epidermophyton. Candida albicans typically causes candidiasis (e.g., intertrigo, thrush), not classic annular dermatophyte lesions. Aspergillus is mainly associated with respiratory or invasive disease in immunocompromised patients rather than superficial ringworm. “Microsporum tuberculosis” is not a recognized dermatophyte species; Microsporum is a dermatophyte genus, but this option is incorrectly named.
Category reason: This question tests the causative organism of a superficial fungal infection (dermatophytes), which is a microorganism-identification concept within Microbiology rather than a nursing intervention or care-priority scenario.

Question 30

Q. A virus is made up of?

Accepted Answer

Answer reason: Viruses contain a nucleic acid genome that is either DNA or RNA, enclosed within a protein capsid. They are not composed of protein alone, and they do not universally contain only DNA or only RNA because different viruses use different genome types. Some viruses additionally have a lipid envelope, but the core composition is nucleic acid plus protein.
Category reason: This question tests the basic structural components of viruses, which is foundational content in microbiology rather than a nursing-care decision.

Question 31

The smallest living organism is?

Accepted Answer

Answer reason: Viruses are generally not considered living organisms because they are acellular and cannot reproduce or carry out metabolism independently; they require a host cell. Among the listed living groups, bacteria are the smallest cellular life forms (prokaryotes), typically around 0.5–5 µm. Algae and protozoa are eukaryotes and are usually much larger than bacteria.
Category reason: This question tests classification of microorganisms and the distinction between cellular life (bacteria) and acellular agents (viruses), which is a core concept in Microbiology.

Question 32

Whooping cough is caused by?

Accepted Answer

Answer reason: Whooping cough (pertussis) is an acute respiratory infection caused by Bordetella pertussis, which is a bacterial pathogen. The organism produces toxins that damage the respiratory epithelium and trigger severe paroxysmal coughing with an inspiratory “whoop.” This bacterial etiology is why macrolide antibiotics can reduce transmission, especially when given early, and why vaccination (DTaP/Tdap) is preventive.
Category reason: This question tests identification of the infectious organism type responsible for a specific disease (pertussis), which is a core topic in Microbiology rather than nursing interventions or care prioritization.

Question 33

Holder’s method of sterilization is?

Accepted Answer

Answer reason: This describes Holder pasteurization, which uses low-temperature long-time moist heat to reduce pathogenic microorganisms, classically for human milk processing. The standard parameters are 62.5–63°C for 30 minutes, followed by rapid cooling. The 72°C for 15 seconds is the high-temperature short-time (HTST) method, not Holder. Dry heat options are incorrect because Holder pasteurization is a moist heat process.
Category reason: This tests knowledge of pasteurization/sterilization parameters and microbial control methods, which is a core concept in Microbiology rather than nursing decision-making.

Question 34

Which organism is used as an indicator for the efficacy of autoclave sterilization?

Accepted Answer

Answer reason: Steam sterilization (autoclaving) is most reliably monitored with highly heat-resistant bacterial spores. The spores of this organism have high resistance to moist heat, so their inactivation provides a strong biologic challenge confirming adequate time/temperature/steam penetration. In contrast, Bacillus subtilis spores are classically used for dry heat and ethylene oxide monitoring rather than standard steam autoclaves.
Category reason: This question tests knowledge of biologic indicators used to verify sterilization efficacy, which is a core microbiology/sterilization concept rather than a nursing judgment or patient-care intervention.

Question 35

BCG is?

Accepted Answer

Answer reason: BCG (Bacille Calmette-Guérin) is derived from an attenuated strain of Mycobacterium bovis, meaning the organism is alive but weakened to stimulate immunity without causing typical disease in immunocompetent hosts. This distinguishes it from inactivated/killed vaccines, which contain nonliving organisms, and from toxoids, which are inactivated bacterial toxins. Because it is a live vaccine, it is generally contraindicated in significant immunosuppression due to risk of disseminated infection.
Category reason: This item tests the vaccine type/classification (live attenuated vs inactivated/killed vs toxoid), which is foundational microbiology/immunization knowledge rather than a nursing care decision.

Question 36

POLIO IS CAUSED BY?

Accepted Answer

Answer reason: C. VIRUS Poliomyelitis is caused by poliovirus, an enterovirus transmitted primarily via the fecal–oral route. After replication in the oropharynx and gastrointestinal tract, it can invade the central nervous system and damage anterior horn motor neurons, leading to acute flaccid paralysis. Protozoa, fungi, and bacteria do not cause poliomyelitis.
Category reason: This question tests identification of the type of pathogen responsible for a specific infectious disease, which is a core Microbiology concept.

Question 37

The process by which, medium is placed at 100°C in flowing steam for 30 minutes each on 3 successive days is?

Accepted Answer

Answer reason: This describes intermittent sterilization using free-flowing steam at 100°C for about 30 minutes on three consecutive days. The first exposure kills vegetative organisms, and the incubation intervals allow any surviving spores to germinate into vegetative forms. Subsequent steam exposures then eliminate those newly germinated bacteria, achieving sterilization for heat-labile media.
Category reason: This question tests knowledge of sterilization techniques and microbial control methods, which is a core topic in Microbiology rather than a nursing judgment/intervention scenario.

Question 38

Chicken Pox can be prevented by the vaccine named?

Accepted Answer

Answer reason: Chickenpox is caused by varicella-zoster virus, and prevention is achieved through immunization specifically targeting this virus. DPT covers diphtheria, pertussis, and tetanus; MMR covers measles, mumps, and rubella; and TT is tetanus toxoid—none protect against varicella-zoster virus. Therefore, the vaccine used to prevent chickenpox is the varicella vaccine.
Category reason: This is a foundational immunization/communicable disease knowledge question about which vaccine prevents a specific viral illness, aligning best with Microbiology.

Question 39

Source of infection of measles is secretion of nose and throat of infection person. Filterable virus of measles is transmitted by?

Accepted Answer

Answer reason: Measles spreads primarily via respiratory droplets/aerosolized particles from the nose and throat secretions of an infected person, especially with coughing or sneezing. It is not transmitted through water supply or food ingestion in typical epidemiologic patterns. Sexual contact is not a primary transmission route; close respiratory exposure is the key mechanism.
Category reason: This question tests the mode of transmission of a viral infectious disease, which is a core concept in microbiology and communicable disease spread.

Question 40

An example of a portal of exit in the chain of infection is?

Accepted Answer

Answer reason: A portal of exit is the route by which a pathogen leaves its reservoir to spread to another host. Respiratory secretions expelled via coughing, sneezing, or talking are classic exit routes for many infectious agents. Intact skin is primarily a barrier to infection rather than an exit route, while a clean environment and sterile field are conditions meant to reduce contamination rather than biological portals.
Category reason: This item tests the chain of infection and modes/portals of transmission, which are core microbiology concepts about how pathogens spread.

Question 41

Which bacteria cause tuberculosis?

Accepted Answer

Answer reason: Tuberculosis is caused by an acid-fast bacillus that primarily infects the lungs and can disseminate to other organs. The organism’s lipid-rich cell wall contributes to its slow growth and characteristic staining properties, which are key to diagnosis. The other listed bacteria more commonly cause community-acquired pneumonia (Streptococcus pneumoniae), respiratory infections like otitis media/bronchitis (Haemophilus influenzae), or gastrointestinal/urinary infections (Escherichia coli), not TB.
Category reason: This question tests identification of the specific causative bacterium of an infectious disease, which is core content in Microbiology.

Question 42

Which parasite causes malaria?

Accepted Answer

Answer reason: Malaria is caused by protozoa of the genus Plasmodium that infect humans via the bite of infected female Anopheles mosquitoes. After entering the bloodstream, the organism first replicates in hepatocytes and then infects red blood cells, producing cyclical fevers and hemolysis. Entamoeba typically causes amebiasis (dysentery/liver abscess), Giardia causes giardiasis, and Leishmania causes leishmaniasis, not malaria.
Category reason: This is a foundational question about which microorganism causes a specific infectious disease, which falls under Microbiology rather than nursing care decisions.

Question 43

What is the infective stage of Entamoeba histolytica?

Accepted Answer

Answer reason: Infection occurs via fecal–oral ingestion of the mature quadrinucleate cyst from contaminated food or water. The cyst survives gastric acidity and then excysts in the small intestine, releasing trophozoites that colonize the colon. Trophozoites are the invasive tissue form but are fragile outside the host and are not the typical transmissible stage. Oocysts are associated with coccidian parasites (e.g., Cryptosporidium), not Entamoeba.
Category reason: This item tests the life cycle and transmission stage of a protozoan parasite, which is a core concept in Microbiology rather than nursing intervention or prioritization.

Question 44

Gram-positive bacteria retain which stain in Gram staining?

Accepted Answer

Answer reason: Gram-positive bacteria have a thick peptidoglycan cell wall that traps the crystal violet–iodine complex during the decolorization step with alcohol/acetone. As a result, they remain purple after decolorization. Gram-negative bacteria lose the crystal violet and instead take up the counterstain (safranin) to appear pink/red.
Category reason: This question tests principles of Gram staining and bacterial cell wall differences, which are core topics in Microbiology.

Question 45

Which helminth egg has a characteristic "barrel-shaped" appearance?

Accepted Answer

Answer reason: Trichuris eggs are classically barrel (lemon) shaped with prominent bipolar plugs, making them distinctive on stool microscopy. Ascaris eggs are typically round/oval with a thick, mammillated shell. Taenia eggs are spherical with a thick, radially striated shell. Enterobius eggs are planoconvex (one side flattened), not barrel shaped.
Category reason: This question tests identification of parasite ova by characteristic morphology, which is a core topic in microbiology/parasitology rather than nursing care decision-making.

Question 46

Which is the gold standard investigation for diagnosing enteric fever?

Accepted Answer

Answer reason: Definitive diagnosis of enteric (typhoid) fever is made by isolating Salmonella Typhi/Paratyphi, and blood culture has the highest yield early in illness when bacteremia is most prominent. Serologic tests like Widal and Typhidot have variable sensitivity/specificity and can be affected by prior vaccination, past infection, and cross-reactivity. Stool culture becomes more useful later as organisms are shed via the biliary tract, but it is less reliable than early blood culture for initial diagnosis. Prior antibiotic exposure can reduce culture sensitivity, so early collection is important.
Category reason: This question tests identification of the diagnostic gold standard for a bacterial infection (Salmonella Typhi) and compares culture versus serologic tests, which is primarily microbiology/diagnostic microbiology knowledge.

Question 47

Food poisoning is caused by all except?

Accepted Answer

Answer reason: It most commonly causes antibiotic-associated colitis and healthcare-associated infectious diarrhea due to disruption of normal gut flora, rather than classic foodborne intoxication from contaminated meals. In contrast, Bacillus cereus and Staph Aureus cause food poisoning via preformed toxins, and Vibrio parahaemolyticus is a well-known foodborne pathogen from raw/undercooked seafood. Therefore it is the exception among the listed organisms.
Category reason: This item tests identification of microorganisms associated with food poisoning versus other causes of diarrhea, which is a foundational Microbiology concept.

Question 48

Ring worm is caused by?

Accepted Answer

Answer reason: Ringworm (tinea) is a superficial dermatophyte infection of keratinized tissues (skin, hair, nails), most commonly caused by Trichophyton, Microsporum, or Epidermophyton species. It produces characteristic annular, scaly lesions due to fungal growth at the periphery with relative central clearing. Protozoa and bacteria do not cause dermatophytosis, and while yeast are fungi, the classic “ringworm” entity refers specifically to dermatophytes rather than Candida-type yeast infections.
Category reason: This question tests the infectious organism responsible for a common superficial skin infection, which is foundational microbiology knowledge rather than a nursing intervention/prioritization scenario.

Question 49

A 40-year-old man presents with fever, headache, and confusion. A lumbar puncture reveals elevated opening pressure and acid-fast bacilli in the cerebrospinal fluid. What is the recommended treatment duration for this condition?

Accepted Answer

Answer reason: Acid-fast bacilli in CSF with signs of meningitis indicates tuberculous meningitis, which requires longer therapy than uncomplicated pulmonary TB due to slow sterilization and high relapse risk in the CNS. Standard management uses an intensive phase with RIPE followed by a prolonged continuation phase (typically total 9–12 months, often 12 months in many guidelines). Short 6-month regimens are generally inadequate for CNS TB. Fluoroquinolones are reserved for drug resistance or intolerance rather than as routine first-line therapy.
Category reason: This question tests identification and duration of antimicrobial therapy for Mycobacterium tuberculosis infection of the CNS, which is primarily an infectious disease/microbiology topic rather than a nursing intervention/prioritization scenario.

Question 50

Which of the following is a parasitic disease caused by Plasmodium?

Accepted Answer

Answer reason: Plasmodium is a protozoan parasite transmitted by the bite of infected female Anopheles mosquitoes. It invades hepatocytes and then red blood cells, producing periodic fever, anemia, and other systemic manifestations typical of malaria. The other options are caused by non-parasitic pathogens: tuberculosis by Mycobacterium tuberculosis (bacterium), cholera by Vibrio cholerae (bacterium), and influenza by influenza viruses.
Category reason: This item tests identification of the causative organism and disease type (protozoan parasite causing malaria), which is a core Microbiology concept rather than a nursing care decision.

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