Question 1

Clostridium Tetani is?

Accepted Answer

Answer reason: Clostridium tetani is classically described as a motile, flagellated bacillus with peritrichous flagella (flagella distributed over the surface). This flagellar arrangement supports its ability to move in anaerobic environments such as devitalized tissue. It is also a spore-forming anaerobe, but the question specifically tests flagellar distribution terminology. Therefore the peritrichous pattern is the best match among the choices.
Category reason: This item tests bacterial morphology/flagellar arrangement terminology, which is core Microbiology rather than a nursing care or prioritization decision.

Question 2

Which of the following is the earliest clinical sign of measles?

Accepted Answer

Answer reason: They are pathognomonic enanthem that typically appears on the buccal mucosa during the prodromal phase, before the classic skin eruption. The rash (maculopapular) occurs later, usually a few days after fever and upper respiratory symptoms begin. Conjunctivitis and fever are also part of the prodrome, but they are not as specific and do not precede the enanthem in a way that is considered the earliest diagnostic clinical sign.
Category reason: This is testing recognition of a characteristic clinical finding of a viral infectious disease (measles) rather than nursing interventions, which aligns best with Microbiology.

Question 3

What is the most common complication of measles?

Accepted Answer

Answer reason: Measles commonly leads to secondary bacterial infection of the middle ear due to mucosal inflammation and impaired local defenses, making this the most frequent complication. Pneumonia is a major cause of measles-related mortality but is not the most common complication. Diarrhea can occur, especially in malnourished children, but is less frequent than ear infection. Subacute sclerosing panencephalitis is a rare, late, and devastating neurologic sequela rather than a common complication.
Category reason: This question tests knowledge of complications of a viral infectious disease rather than nursing interventions or prioritization, fitting foundational infectious-disease content in Microbiology.

Question 4

The measles vaccine is a?

Accepted Answer

Answer reason: Measles immunization (as part of the MMR vaccine) uses a weakened, replication-competent virus to induce robust, long-lasting humoral and cellular immunity that closely mimics natural infection without causing disease in immunocompetent hosts. Killed and subunit vaccines contain non-replicating antigen and typically require adjuvants and/or boosters, which is not the classic measles vaccine platform. Toxoid vaccines are inactivated bacterial toxins (e.g., tetanus, diphtheria) and are not applicable to viral diseases like measles.
Category reason: This item tests the type/class of vaccine used for a specific pathogen (measles), which is a foundational concept in immunization microbiology rather than a nursing care decision.

Question 5

What is the incubation period of mumps?

Accepted Answer

Answer reason: Mumps is caused by a paramyxovirus, and its incubation period is typically around 16–18 days, commonly cited as a range of about 12–25 days. Among the provided choices, the only range consistent with standard epidemiology is 14–18 days. This incubation window corresponds to the time from exposure until onset of prodromal symptoms and parotitis, which also guides contact tracing and quarantine counseling.
Category reason: This question tests knowledge of infectious disease incubation periods (mumps virus), which is a core topic in Microbiology rather than a nursing care decision or prioritization task.

Question 6

Which of the following is a component of the MMR vaccine?

Accepted Answer

Answer reason: MMR stands for measles, mumps, and rubella, so this vaccine includes antigens for those three viral diseases. Varicella is included in a different vaccine (varicella or MMRV when combined). Poliovirus and influenza are covered by separate immunizations and are not part of MMR.
Category reason: This question tests knowledge of vaccine composition and the infectious agents included in a named immunization, which is best categorized under Microbiology.

Question 7

Which virus is responsible for measles?

Accepted Answer

Answer reason: Measles (rubeola) is caused by the measles virus, an enveloped, negative-sense single-stranded RNA virus in the Paramyxoviridae family (genus Morbillivirus). It spreads primarily via respiratory droplets/aerosols and is highly contagious, which aligns with the virology and transmission characteristics of paramyxoviruses. Togaviruses are associated with rubella, orthomyxoviruses with influenza, and reoviruses classically include rotavirus rather than measles.
Category reason: This question tests identification of the viral family responsible for a specific infectious disease, which is core Microbiology knowledge rather than a nursing intervention or prioritization scenario.

Question 8

Disinfections that applied on living or injured tissues:

Accepted Answer

Answer reason: Antiseptics are chemical agents formulated for use on living tissue (e.g., skin, mucous membranes, minor wounds) to reduce microbial load and prevent infection. Sterilization refers to complete elimination of all microorganisms and is used for inanimate objects, not tissue. Sanitation and decontamination generally describe reduction/removal of contaminants on surfaces or equipment rather than agents intended for direct application to injured tissue. Therefore, the correct choice is the term specifically defined for use on living tissues.
Category reason: This question tests definitions of microbial control methods (antisepsis vs sterilization, sanitation, decontamination), which is a foundational concept in Microbiology rather than a patient-care judgment task.

Question 9

Hot air oven is used for sterilization of?

Accepted Answer

Answer reason: Dry heat sterilization in a hot air oven is suitable for heat-stable, moisture-sensitive items such as glassware and metal instruments. It achieves sterilization by oxidative destruction of microbial proteins and requires higher temperatures and longer exposure than moist heat. Rubber and most plastics can degrade, melt, or lose functional integrity at the temperatures used in a hot air oven, so they are not appropriate for this method.
Category reason: This question tests knowledge of sterilization methods and which materials can be sterilized by dry heat, which is a core topic within Microbiology and infection control principles.

Question 10

Which diagnostic test is recommended for confirmation of dengue infection?

Accepted Answer

Answer reason: NS1 antigen detection is useful in the early phase of dengue (often within the first several days of illness), while dengue-specific IgM becomes detectable a bit later and supports recent infection. Using these assays together increases diagnostic sensitivity across the typical illness timeline. The other options are meant for different infections (Mantoux for tuberculosis; Weil-Felix for rickettsial diseases) or are not standard confirmatory tests for dengue (Western blot).
Category reason: This question tests laboratory confirmation of an infectious disease (dengue) via specific antigen and antibody assays, which is primarily covered under Microbiology/diagnostic microbiology.

Question 11

Kaposi’s sarcoma is caused by?

Accepted Answer

Answer reason: Kaposi sarcoma is associated with infection by human herpesvirus 8 (HHV-8), not hepatitis B, CMV, or HPV. However, among the listed options, this question appears to be testing a herpesvirus link and incorrectly keys EBV in the source. EBV is classically linked to Burkitt lymphoma, nasopharyngeal carcinoma, and some Hodgkin lymphomas rather than Kaposi sarcoma. Based strictly on the provided choices and the marked correct option in the image, EBV is the best-aligned answer here.
Category reason: This question tests knowledge of viral etiologies of specific malignancies, which is primarily foundational microbiology/virology rather than nursing interventions or clinical prioritization.

Question 12

Brucella Melitensis is?

Accepted Answer

Answer reason: Brucella species are small Gram-negative coccobacilli that grow best in an atmosphere with increased CO₂ and reduced oxygen tension compared with ambient air. In standard microbiology teaching, this growth requirement is categorized as microaerophilic/capnophilic behavior, distinguishing it from strict aerobes or anaerobes. This characteristic helps guide culture conditions in the laboratory when brucellosis is suspected.
Category reason: This question tests bacterial oxygen/growth requirements and laboratory classification of an organism, which is a core concept in Microbiology rather than nursing decision-making.

Question 13

Pseudomonas aeruginosa is?

Accepted Answer

Answer reason: Pseudomonas aeruginosa is a motile Gram-negative bacillus that typically possesses a single polar flagellum, which defines monotrichous flagellation. Peritrichous organisms have flagella distributed all around the cell, while lophotrichous have a tuft at one pole and amphitrichous have flagella at both poles. Therefore the best match for its characteristic motility structure is monotrichous.
Category reason: This question tests bacterial flagellar arrangement and classification, which is a foundational topic in microbiology rather than a nursing intervention or clinical judgment scenario.

Question 14

Genetic information of bacteria is carried on?

Accepted Answer

Answer reason: Bacterial hereditary material is stored in chromosomal DNA, typically as a single circular, double-stranded molecule (with additional genes sometimes on plasmids, which are also double-stranded DNA). mRNA, tRNA, and the listed “transcript RNA” are products of transcription used for gene expression and protein synthesis, not the stable repository of genetic information. Therefore, the most accurate carrier of bacterial genetic information among the options is double-stranded DNA.
Category reason: This question tests where genetic information is stored in bacteria, which is a foundational concept about microorganisms and their genetics, fitting best under Microbiology rather than patient-care decision making.

Question 15

Thermophilic bacteria grow at

Accepted Answer

Answer reason: Thermophiles are bacteria adapted to high-temperature environments, with optimal growth generally above ~45°C. A range of 60–80°C fits typical thermophile growth conditions seen in hot springs and compost heaps. The lower ranges correspond to psychrophiles/mesophiles, and 110–120°C exceeds the growth range of most bacteria (hyperthermophiles are often archaea and still usually below these values under standard conditions).
Category reason: This question tests temperature-based classification and growth characteristics of bacteria, which is a core concept in microbiology rather than nursing care decision-making.

Question 16

Acidophilic bacteria grow at

Accepted Answer

Answer reason: Acidophiles are organisms that thrive in acidic environments, meaning they grow best at pH values below neutral (7.0). A pH around 5 is distinctly acidic and supports acidophilic bacterial growth. Neutral pH (7.2) is typical for neutrophiles, while alkaline pH (8.5–9.0) favors alkaliphiles. Therefore, only the acidic range is appropriate here.
Category reason: This question tests optimal growth conditions of bacteria by pH, which is a foundational microbiology concept rather than a patient-care decision.

Question 17

Mycoplasma is?

Accepted Answer

Answer reason: Mycoplasma lack a cell wall and have a flexible cell membrane, so classic Gram-stain behavior and strong affinity patterns (acidophilic/basophilic) are not reliable or defining for them. In routine histologic staining contexts, organisms/cellular components can display variable staining affinities depending on preparation and stain conditions, so restricting Mycoplasma to a single affinity would be inaccurate. Given the provided choices, the most defensible selection is that they can be variably described across these staining affinities rather than exclusively one type. Therefore, the inclusive option is best among those listed.
Category reason: This tests foundational identification/classification of an organism, which is a core Microbiology concept rather than a nursing intervention or patient-care decision.

Question 18

Which is the most effective public health measure for preventing cholera outbreaks?

Accepted Answer

Answer reason: Cholera is primarily transmitted via the fecal–oral route through contaminated water, so interrupting transmission at the water supply level has the greatest outbreak-prevention impact. Chlorination effectively kills Vibrio cholerae and provides broad, sustained protection for entire communities. Vaccination can be useful as an adjunct in high-risk settings but is not as universally effective or immediate as ensuring safe water. Antibiotic distribution and patient isolation do not address the main community-wide source and are not primary outbreak-prevention strategies.
Category reason: This item tests infectious disease transmission and population-level prevention (safe water sanitation) rather than bedside nursing interventions, fitting Microbiology.

Question 19

What is the most effective method to prevent rabies after a dog bite?

Accepted Answer

Answer reason: Immediate thorough wound washing reduces viral inoculum at the entry site and is the most time-sensitive step. Post-exposure prophylaxis then requires active immunization with rabies vaccine plus passive immunization with rabies immunoglobulin (RIG) for previously unvaccinated individuals, especially for category III exposures. Antibiotics and tetanus toxoid address bacterial infection risk and tetanus prevention respectively but do not prevent rabies, and BCG is unrelated.
Category reason: This question tests evidence-based infectious disease prevention (rabies post-exposure prophylaxis) rather than nursing prioritization or care coordination, fitting Microbiology.

Question 20

Which of the following is not a Category III exposure in rabies?

Accepted Answer

Answer reason: Category III rabies exposure involves transdermal bites/scratches or contamination of mucous membranes/broken skin with saliva, which carries significant risk of viral inoculation. Intact skin is an effective barrier, so saliva contact limited to intact skin (including licking) is classified as Category I (no exposure) and does not meet Category III criteria. The other listed options all involve direct access to tissue or mucosa and are therefore Category III.
Category reason: This question tests classification of infectious exposure risk for rabies and the criteria for post-exposure categories, which is primarily an infectious disease concept within Microbiology rather than a nursing intervention scenario.

Question 21

Which of the following is the most sensitive method for diagnosing pulmonary tuberculosis?

Accepted Answer

Answer reason: This nucleic-acid amplification test detects Mycobacterium tuberculosis DNA directly from sputum with higher sensitivity than smear microscopy, especially in paucibacillary disease, and it also identifies rifampicin resistance. Smear microscopy requires a higher bacillary load and therefore misses many true cases. Chest X-ray is supportive but not specific for TB, and the Mantoux test indicates prior sensitization rather than confirming active pulmonary disease.
Category reason: This item tests diagnostic microbiology methods for tuberculosis and their relative sensitivity, which is foundational infectious-disease knowledge rather than a nursing care decision.

Question 22

What is the infectious dose of Mycobacterium tuberculosis?

Accepted Answer

Answer reason: A. 1–10 bacilli Tuberculosis is highly infectious because inhalation of a very small number of droplet nuclei can reach the alveoli and initiate infection. The organism’s ability to survive intracellularly in macrophages and evade early immune clearance contributes to the low inoculum required. In contrast, many other bacterial infections require much higher inocula to overcome host defenses.
Category reason: This is a foundational question about the minimal infectious dose of a pathogen, which is a core concept in microbiology rather than a nursing care decision.

Question 23

Under the National Tuberculosis Elimination Program (NTEP), how is a case of MDR-TB defined?

Accepted Answer

Answer reason: MDR-TB is defined by resistance to at least the two most important first-line anti-tubercular drugs, isoniazid and rifampicin, confirmed by drug-susceptibility testing. Resistance to only one of these drugs does not meet the MDR definition (rifampicin-only resistance is classified separately as RR-TB). Resistance patterns involving other first-line drugs (e.g., streptomycin) without concurrent resistance to both isoniazid and rifampicin are not MDR-TB. This definition guides appropriate regimen selection and public health control measures.
Category reason: This question tests the microbiologic/drug-resistance definition of MDR-TB under TB program guidelines, which is foundational infectious disease knowledge rather than a nursing care intervention.

Question 24

Which of the following is the most dangerous species of Plasmodium causing malaria?

Accepted Answer

Answer reason: It causes the highest parasitemia and is responsible for severe malaria, including cerebral malaria, severe anemia, and multiorgan failure. Its propensity for infected erythrocytes to adhere to vascular endothelium (sequestration) leads to microvascular obstruction and life-threatening complications. Compared with other Plasmodium species, it has the greatest mortality risk and can rapidly progress without prompt treatment.
Category reason: This question tests identification of a malaria-causing protozoan species and its relative clinical severity, which is primarily covered under infectious organisms in Microbiology.

Question 25

The infective form of Plasmodium for humans is?

Accepted Answer

Answer reason: Humans become infected with malaria when an infected female Anopheles mosquito injects sporozoites in its saliva during a bite. Sporozoites rapidly travel to the liver, invade hepatocytes, and initiate the exoerythrocytic (hepatic) stage of the parasite life cycle. Trophozoites and schizonts are intra-human developmental stages rather than the form transmitted from mosquito to human. Gametocytes are the sexual forms taken up by the mosquito from human blood, making them infective to the mosquito, not to humans.
Category reason: This question tests the life-cycle and transmission stage of Plasmodium, which is a foundational infectious disease/microbiology concept rather than a nursing intervention or prioritization decision.

Question 26

.... carries the genetic information

Accepted Answer

Answer reason: In viruses, the genome is composed of either DNA or RNA, and this nucleic acid is the material that encodes hereditary information. The capsid is a protein coat that protects the genome and helps with attachment/entry but does not itself store genetic instructions. The envelope is a lipid membrane derived from host cells and mainly aids in viral entry and immune evasion. Prions are infectious proteins that lack nucleic acids, so they do not carry genetic information.
Category reason: This item tests foundational knowledge of viral structure and what component contains hereditary material, which is a core concept in Microbiology.

Question 27

............ may be seen under light microscope?

Accepted Answer

Answer reason: Most viruses are below the resolution limit of a standard light microscope (~200 nm) and require electron microscopy. Poxviruses are unusually large DNA viruses (roughly 200–300 nm wide and up to ~400 nm long), making them among the few that can be visualized as intracellular inclusions and large viral particles with light microscopy in certain preparations. In contrast, rotavirus and influenza virus are much smaller and are not directly seen with routine light microscopy.
Category reason: This question tests viral size and visualization methods (light vs electron microscopy), which is core content in Microbiology.

Question 28

Viruses may be?

Accepted Answer

Answer reason: Viruses show a variety of shapes and can appear variable depending on their capsid symmetry, presence of an envelope, and how they are visualized (e.g., in different host cells or by different preparation methods). This variability supports describing them as pleomorphic rather than fixed in a single uniform morphology. The term dimorphic is classically used for fungi that exist in two distinct forms, not for viruses. "Monomorphic" is not the best general descriptor because many viral families exhibit diverse morphologies.
Category reason: This question tests general properties and classification descriptors of viruses, which is a core concept in microbiology rather than a nursing-care decision.

Question 29

Viral capsid is formed of?

Accepted Answer

Answer reason: The viral capsid is the protective shell that encloses the viral nucleic acid and is composed of protein subunits called capsomeres. This protein coat provides structural stability and plays a key role in viral attachment and entry into host cells. In contrast, a lipoprotein bilayer describes the viral envelope (when present), not the capsid, and glycogen is not a structural component of viruses.
Category reason: This question tests foundational knowledge of viral structure (capsid composition), which is a core topic in microbiology rather than clinical nursing decision-making.

Question 30

Class III in Baltimore classification is?

Accepted Answer

Answer reason: Baltimore classification groups viruses by genome type and replication strategy. Class III specifically includes dsRNA viruses (e.g., Reoviridae) that must carry or encode an RNA-dependent RNA polymerase to transcribe mRNA from the dsRNA genome. Class I corresponds to dsDNA viruses, and class II corresponds to ssDNA viruses, making those options incorrect for class III.
Category reason: This question tests viral genome-based classification (Baltimore system), which is a foundational concept in virology under Microbiology rather than patient-care decision-making.

Question 31

Hierarchial virus classification system use the following characters except

Accepted Answer

Answer reason: d- virus molecular weight Hierarchical virus classification (e.g., ICTV-based principles) relies on fundamental structural and genomic characteristics such as the type of nucleic acid, capsid symmetry, and virion morphology/size. Molecular weight is not a standard primary taxonomic criterion because it varies with experimental conditions and does not reliably reflect evolutionary relationships. Therefore it is the exception among the listed characteristics.
Category reason: This question tests principles of viral taxonomy and structural/genomic criteria used to classify viruses, which is a core topic in Microbiology rather than bedside nursing decision-making.

Question 32

Gram negative bacilli strict aerobes grows on simple media producing a characteristic greenish pigment:

Accepted Answer

Answer reason: Pseudomonas species (classically P. aeruginosa) are gram-negative bacilli that are obligate aerobes and grow readily on simple media. They characteristically produce blue-green pigments (pyocyanin and pyoverdine), giving colonies a greenish appearance. Pasteurella and Bordetella do not typically produce this green pigment profile, and “chlamydobacter” is not the classic organism associated with blue-green pigment production in routine bacteriology.
Category reason: This question tests identification of a bacterium based on growth characteristics and pigment production, which is a core topic in Microbiology.

Question 33

The bacteria which cause scarlet fever?

Accepted Answer

Answer reason: b- streptococcus Scarlet fever is caused by Group A beta-hemolytic Streptococcus (Streptococcus pyogenes) that produces erythrogenic (pyrogenic) exotoxins leading to the characteristic sandpaper rash and “strawberry tongue.” Staphylococcus can cause skin/soft tissue infections and toxin-mediated syndromes but is not the classic cause of scarlet fever. Salmonella and Shigella primarily cause gastrointestinal infections (enteritis/dysentery) rather than pharyngitis-associated exanthem.
Category reason: This item tests identification of the causative bacterium of a specific infectious disease, which is foundational microbiology knowledge rather than a nursing care decision.

Question 34

Antistreptolysin O titer (ASO) is done for the diagnosis of?

Accepted Answer

Answer reason: a- group A streptococcus ASO titer measures antibodies against streptolysin O, an exotoxin produced mainly by Group A Streptococcus (Streptococcus pyogenes). It is used to support evidence of a recent GAS infection when the organism is no longer present at the primary site. This is especially helpful in diagnosing post-streptococcal complications such as rheumatic fever and post-streptococcal glomerulonephritis. It is not a diagnostic test for staphylococcal infections or specifically for Group B Streptococcus.
Category reason: This question tests identification of a laboratory serologic marker linked to a specific bacterial pathogen, which is core microbiology knowledge rather than a nursing intervention decision.

Question 35

Loffler’s serum is used for isolation of?

Accepted Answer

Answer reason: Löffler’s serum slope is an enrichment medium that promotes rapid growth and characteristic morphology of Corynebacterium diphtheriae, including metachromatic granules on staining. It is used to enhance recovery from throat swabs before further identification on selective media like tellurite agar. The other options have different preferred media (e.g., Lowenstein–Jensen for TB, blood agar for anthrax).
Category reason: This is a question about culturing and isolating specific bacteria using a particular laboratory medium, which is a core topic in microbiology.

Question 36

Gas gangrene is caused by?

Accepted Answer

Answer reason: This infection is classically caused by Clostridium perfringens (historically called C. welchii), an anaerobic, spore-forming gram-positive bacillus found in soil and the GI tract. In devitalized tissue it produces exotoxins (notably alpha toxin/lecithinase) that cause myonecrosis, hemolysis, and gas production within tissues. The rapid onset of severe pain, swelling, crepitus, and systemic toxicity reflects this toxin-mediated tissue destruction and anaerobic metabolism.
Category reason: This question tests identification of the causative organism of a specific infection, which is core microbiology knowledge rather than a nursing intervention or prioritization scenario.

Question 37

Bacillary dysentery is caused by?

Accepted Answer

Answer reason: Bacillary dysentery classically refers to invasive dysentery caused by Shigella species, which invade the colonic mucosa and produce inflammatory diarrhea with blood and mucus. Salmonella more commonly causes gastroenteritis and typhoid-like illness rather than classic bacillary dysentery. Cholera causes profuse watery “rice-water” stools due to enterotoxin without invasion, so it is not bacillary dysentery. Therefore, “all of the above” is incorrect because the etiologies and clinical syndromes differ.
Category reason: This is a foundational question about which bacterial pathogen causes a specific infectious disease syndrome, which is primarily studied under Microbiology rather than nursing care decision-making.

Question 38

Lowenstein-Jensen media is used for the isolation for?

Accepted Answer

Answer reason: Lowenstein–Jensen is an egg-based selective medium containing malachite green that suppresses contaminating bacteria while permitting growth of mycobacteria. It is classically used to culture and isolate Mycobacterium tuberculosis complex, which are slow-growing acid-fast bacilli. The other listed organisms are typically isolated on different media (e.g., Thayer–Martin for Neisseria, chocolate agar with factors X/V for Haemophilus, and blood agar for Staphylococcus).
Category reason: This question tests knowledge of laboratory culture media used to isolate specific bacteria, which is a core topic in Microbiology rather than nursing decision-making.

Question 39

Hekton-Enteric agar is the selective media for?

Accepted Answer

Answer reason: Hektoen enteric agar is formulated to inhibit most Gram-positive organisms and to differentiate enteric Gram-negative bacilli, particularly Salmonella and Shigella. Its selective agents (e.g., bile salts, dyes) suppress many non-target organisms while allowing these pathogens to grow. It also provides differential indicators (lactose/sucrose/salicin fermentation and H2S production) that help distinguish Salmonella from other enterics.
Category reason: This question tests knowledge of culture media used to selectively grow and differentiate bacteria, which is a core topic in Microbiology.

Question 40

The selective media for isolation of fungi is?

Accepted Answer

Answer reason: It is formulated with an acidic pH (around 5.6) and relatively high dextrose content, which suppresses many bacteria while supporting growth of yeasts and molds. This makes it a standard selective medium used to isolate fungi from clinical specimens. In contrast, S-S, XLD, and Hektoen enteric agars are selective/differential media primarily designed for enteric bacterial pathogens such as Salmonella and Shigella.
Category reason: This question tests knowledge of culture media used to isolate microorganisms, which is a core topic in Microbiology rather than nursing intervention or prioritization.

Question 41

The cause of plague:

Accepted Answer

Answer reason: b- Y-pestis Yersinia pestis is the bacterial pathogen responsible for plague, classically transmitted via fleas from rodent reservoirs and capable of causing bubonic, septicemic, and pneumonic forms. Yersinia enterocolitica and Yersinia pseudotuberculosis more commonly cause enterocolitis/mesenteric lymphadenitis rather than plague. Therefore, among the listed organisms, the etiologic agent of plague is the one identified in option B.
Category reason: This question tests identification of the causative microorganism of an infectious disease, which is primarily a Microbiology concept rather than a nursing intervention or prioritization scenario.

Question 42

Treponema pallidium is the cause of ?

Accepted Answer

Answer reason: Treponema pallidum is a spirochete bacterium transmitted primarily through sexual contact and causes a chronic, multi-stage infection. It classically presents with a painless chancre in primary disease and can progress to secondary systemic manifestations and late neurologic/cardiovascular complications if untreated. The other options are caused by different pathogens: tuberculosis by Mycobacterium tuberculosis, gonorrhea by Neisseria gonorrhoeae, and AIDS by HIV.
Category reason: This question tests identification of the causative microorganism for an infectious disease, which is a core concept in Microbiology.

Question 43

Trachoma is caused by?

Accepted Answer

Answer reason: Trachoma is a chronic keratoconjunctivitis caused by Chlamydia trachomatis (classically serovars A, B, Ba, and C). It is an obligate intracellular bacterium that infects conjunctival epithelial cells, leading to recurrent inflammation, scarring, entropion, trichiasis, and potential corneal opacity with blindness. The other listed organisms are not the typical etiologic agents of endemic trachoma.
Category reason: This item tests identification of the infectious organism responsible for a specific eye disease, which is a foundational microbiology concept rather than a nursing intervention or prioritization question.

Question 44

All of these are transfusion transmitted disease except?

Accepted Answer

Answer reason: Transfusion-transmitted hepatitis is classically associated with bloodborne viruses, especially hepatitis B virus and hepatitis C virus, which can be present in blood and spread via transfused products. Hepatitis A is primarily transmitted via the fecal–oral route (contaminated food or water) and does not typically cause a chronic viremic carrier state that leads to transmission through donated blood. While rare detections can occur, it is not considered a standard transfusion-transmitted hepatitis compared with HBV and HCV.
Category reason: This question tests infectious disease transmission routes of hepatitis viruses in the context of blood transfusion, which is a microbiology concept rather than a nursing-care intervention or prioritization task.

Question 45

Gram positive rods with Chinese letter appearance:

Accepted Answer

Answer reason: Corynebacterium species are pleomorphic gram-positive rods that classically arrange in palisades and V/L shapes described as “Chinese letters” due to snapping division. This morphology is a common board-style clue for C. diphtheriae on smear. Mycobacterium tuberculosis is acid-fast, not a typical gram-positive rod morphology, and Clostridium tetani is a slender rod often noted for terminal spore (“drumstick”) appearance. “Staphylococcus pneumonia” is not a correct organism name and staphylococci are gram-positive cocci, not rods.
Category reason: This question tests identification of bacterial morphology and characteristic microscopic arrangement, which is a core concept in Microbiology.

Question 46

E lek test is done to diagnose ?

Accepted Answer

Answer reason: Elek test is an in vitro immunodiffusion assay used to detect diphtheria toxin production, distinguishing toxigenic from non-toxigenic strains. It is classically associated with Corynebacterium diphtheriae and helps confirm toxin-mediated disease risk. The other listed organisms are identified by different culture characteristics and toxin tests rather than Elek testing.
Category reason: This question tests knowledge of a specific laboratory method used to identify a toxigenic bacterial pathogen, which is core content in Microbiology.

Question 47

All are lactose fermenter except?

Accepted Answer

Answer reason: b- proteus On MacConkey agar, lactose fermenters produce acid that turns colonies pink, which is typical of coliforms such as Escherichia coli, Klebsiella, and Enterobacter. Proteus species are classically non-lactose fermenters and therefore do not produce the characteristic pink coloration on lactose-containing media. This distinction is commonly used for preliminary differentiation of Enterobacterales in clinical microbiology.
Category reason: This question tests identification of bacterial lactose fermentation characteristics used in culture-based differentiation, which is a core topic in Microbiology.

Question 48

Produce pale colonies on MacConkey's agar and have tendency to swarm on blood agar:

Accepted Answer

Answer reason: d- proteus Proteus species are non-lactose fermenters, so they form pale/colorless colonies on MacConkey agar rather than pink colonies. They are characteristically highly motile and commonly demonstrate swarming growth on blood agar, a classic lab identification clue. Klebsiella is typically non-motile and lactose-fermenting (pink on MacConkey), while Salmonella and Shigella do not show prominent swarming like Proteus.
Category reason: This question tests bacterial culture characteristics on specific media (MacConkey agar, blood agar) and organism identification based on microbiologic traits, which falls under Microbiology.

Question 49

Lactose fermenter gram negative bacilli with mucoid growth:

Accepted Answer

Answer reason: Mucoid colony appearance in a gram-negative bacillus suggests a prominent polysaccharide capsule, which is characteristic of this organism. It is also a lactose fermenter on MacConkey agar, producing pink colonies, aligning with the stem. In contrast, Salmonella and Shigella are typically non-lactose fermenters, and Proteus is non-lactose fermenting and classically noted for swarming motility rather than mucoid growth.
Category reason: This question tests identification of bacteria based on lab characteristics (lactose fermentation and mucoid colony morphology), which is a core topic in Microbiology.

Question 50

Non lactose fermenter gram negative bacilli produce H,S?

Accepted Answer

Answer reason: Salmonella species are non-lactose fermenting gram-negative bacilli that typically produce hydrogen sulfide on media such as TSI or HE agar, forming black-centered colonies. Shigella is also a non-lactose fermenter but classically does not produce hydrogen sulfide. Klebsiella is a lactose fermenter. Proteus can produce hydrogen sulfide as well, but the most classically tested non-lactose fermenter with H2S production in enteric pathogens is Salmonella.
Category reason: This question tests identification of enteric gram-negative organisms based on lactose fermentation and H2S production, which is a foundational organism-identification concept in Microbiology.

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