Notes in PTH.S1.L13.Infectious Disease

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Emerging Infectious Diseases
Fungal Infections
General Principles of Microbial Pathogenesis
Parasitic Infections
Sexually Transmitted Infections
Viral Infections

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Published	12/09/2024	Bacterial Infections are categorized into (3):
Published	12/09/2024	Type of Staphylococcus bacteria:Pyogenic gram-positive coccus that forms clusters resembling bunches of grapes
Published	12/09/2024	Type of Staphylococcus bacteria:Coagulase-negative staphylococci  which causes opportunistic infections in catheterized patients, patients with p…
Published	12/09/2024	Type of Staphylococcus bacteria:Common cause of urinary tract infections
Published	12/09/2024	PathogenesisS. aureus virulence factors Surface receptors for fibrinogen {{c1::(“clumping factor”) }}{{c2::Polysaccharide capsule}} enabling atta…
Published	12/09/2024	Which of the following S. aureus virulence factors enables resistance to phagocytosis?a) Exfoliative toxinsb) Polysaccharide capsulec) Protein Ad) Sup…
Published	12/09/2024	How does protein A of S. aureus help in immune evasion?a) By forming pores in the plasma membrane of host cellsb) By cleaving desmosomal proteinsc) By…
Published	12/09/2024	Which S. aureus toxin is a sphingomyelinase?a) α-toxinb) β-toxinc) δ-toxind) γ-toxin
Published	12/09/2024	What is the primary function of exfoliative toxins A and B in S. aureus infections?a) Lysis of red blood cellsb) Formation of pores in the plasma memb…
Published	12/09/2024	Superantigens in S. aureus cause toxic shock syndrome by:a) Lysing phagocytesb) Activating up to 20% of T lymphocytesc) Forming fragile bullae in the …
Published	12/09/2024	Which of the following is NOT a type of pyogenic inflammation caused by S. aureus?a) Furuncleb) Hidradenitisc) Felond) Bronchiectasis
Published	12/09/2024	What distinguishes S. aureus lung infections from those caused by S. pneumoniae?a) Lack of polymorphonuclear infiltrateb) Greater tissue destructionc)…
Published	12/09/2024	Staphylococcal scalded-skin syndrome is most common in:a) Elderly patientsb) Adults with immunodeficiencyc) Children with nasopharyngeal or skin infec…
Published	12/09/2024	In Ritter disease, desquamation of the epidermis occurs at which layer?a) Stratum corneumb) Stratum basalec) Granulosa layerd) Dermis
Published	12/09/2024	Which of the following conditions is NOT caused by Streptococcus pyogenes (Group A)?a) Pharyngitisb) Rheumatic feverc) Chorioamnionitisd) Erysipelas
Published	12/09/2024	Which Streptococcus species is a common cause of sepsis and meningitis in neonates?a) Streptococcus pyogenesb) Streptococcus pneumoniaec) Streptococcu…
Published	12/09/2024	What is the most common Streptococcus species associated with community-acquired pneumonia in older adults?a) Streptococcus mutansb) Streptococcus pne…
Published	12/09/2024	Which Streptococcus group includes species commonly found in normal oral microbiota and associated with endocarditis?a) Streptococcus pneumoniaeb) Str…
Published	12/09/2024	What condition is most commonly caused by Streptococcus mutans?a) Dental cariesb) Meningitisc) Scarlet feverd) Toxic shock syndrome
Published	12/09/2024	Which of the following infections is commonly caused by Enterococci?a) Erysipelasb) Scarlet feverc) Endocarditisd) Pharyngitis
Published	12/09/2024	What is a defining characteristic of erysipelas caused by S. pyogenes?a) A diffuse rash with no clear bordersb) A sharp, well-demarcated, serpiginous …
Published	12/09/2024	Streptococcal pharyngitis is a major antecedent of which postinfectious syndrome?a) Rheumatic feverb) Poststreptococcal glomerulonephritisc) Scarlet f…
Published	12/09/2024	Scarlet fever is most commonly associated with:a) S. pneumoniae infectionsb) S. pyogenes pharyngitisc) Enterococcus urinary tract infectionsd) Viridan…
Published	12/09/2024	What is the hallmark of S. pneumoniae infection in the lungs?a) Diffuse interstitial pneumoniab) Formation of abscesses in the tonsillar cryptsc) Loba…
Published	12/09/2024	What is the main virulence factor of Corynebacterium diphtheriae?a) Capsule that prevents phagocytosisb) Exotoxin that inhibits host cell protein synt…
Published	12/09/2024	The A fragment of the diphtheria toxin specifically:a) Binds to elongation factor-2 (EF2)b) Catalyzes the transfer of ADP-ribose to EF2, inhibiting it…
Published	12/09/2024	Which of the following is a characteristic feature of cutaneous diphtheria?a) Chronic ulcers with a dirty gray membraneb) Systemic damage due to exoto…
Published	12/09/2024	The pseudomembrane in respiratory diphtheria is formed by:a) A thick layer of bacteria and pusb) Coagulation of dense fibrinosuppurative exudate and n…
Published	12/09/2024	What serious complications can occur if the pseudomembrane in diphtheria sloughs off?a) Chronic ulcers and rashb) Asphyxiation and bleedingc) Pneumoni…
Published	12/09/2024	What is the most common source of Listeria monocytogenes infections?a) Contaminated waterb) Contaminated dairy products or processed fruits and vegeta…
Published	12/09/2024	Which of the following populations is most at risk for severe Listeria monocytogenes infections?a) Healthy adultsb) Pregnant women and neonatesc) Chil…
Published	12/09/2024	What is the role of listeriolysin O in the pathogenesis of listeriosis?a) Binds to host cell receptors for entryb) Forms pores to allow bacteria to es…
Published	12/09/2024	Which bacterial protein facilitates the actin-based motility of Listeria monocytogenes within host cells?a) Listeriolysin Ob) Act Ac) Phospholipase Cd…
Published	12/09/2024	What severe condition can Listeria monocytogenes cause in immunocompromised individuals?a) Pneumoniab) Meningitis with exudative inflammationc) Scarle…
Published	12/09/2024	What is the primary mode of transmission of Bacillus anthracis to humans?a) Airborne droplets from infected individualsb) Handling or consuming produc…
Published	12/09/2024	Which form of anthrax accounts for 95% of naturally occurring infections?a) Inhalational anthraxb) Cutaneous anthraxc) Gastrointestinal anthraxd) Syst…
Published	12/09/2024	What is a hallmark feature of cutaneous anthrax after vesicle rupture?a) Hemorrhagic bullaeb) Black eschar formationc) Rapid tissue necrosisd) Purulen…
Published	12/09/2024	What is the role of the protective antigen (PA) in the pathogenesis of anthrax?a) Causes edema by increasing cAMP levelsb) Serves as the delivery syst…
Published	12/09/2024	Which toxin component of Bacillus anthracis disrupts mitogen-activated protein kinase kinases (MAPKKs)?a) Protective antigen (PA)b) Edema factor (EF)c…
Published	12/09/2024	What is the typical mortality rate of gastrointestinal anthrax?a) 5%b) 20%c) 40%d) 75%
Published	12/09/2024	In inhalational anthrax, where do spores germinate and release toxins?a) Nasal cavityb) Bronchic) Lymph nodesd) Alveolar walls
Published	12/09/2024	What is the characteristic histopathological feature of Bacillus anthracis lesions?a) Presence of large, boxcar-shaped, gram-positive bacteria in chai…
Published	12/09/2024	In inhalational anthrax, what is commonly seen in the mediastinum?a) Pneumonia with consolidationb) Hemorrhagic foci and mediastinitisc) Necrotizing g…
Published	12/09/2024	What is observed in the lymph nodes of individuals with inhalational anthrax?a) Extensive fibrosis and calcificationb) Expansion due to edema and macr…
Published	12/09/2024	Which of the following staining techniques is used to identify Bacillus anthracis in tissue samples?a) Gram stainb) Ziehl-Neelsen stainc) Brown and Br…
Published	12/09/2024	What histopathological finding is typically associated with anthrax lesions at any site?a) Necrosis with exudative inflammation rich in neutrophils an…
Published	12/09/2024	Which of the following is true about Neisseria species?a) They are anaerobic, gram-negative diplococcib) Pathogenic Neisseria spp. can secrete single-…
Published	12/09/2024	What is a primary cause of bacterial meningitis, particularly among adolescents and young adults?a) Neisseria gonorrhoeaeb) Neisseria meningitidisc) S…
Published	12/09/2024	Which of the following is a common consequence of untreated Neisseria gonorrhoeae infection in women?a) Urethritisb) Infertility or ectopic pregnancyc…
Published	12/09/2024	In people who lack the complement proteins that form the membrane attack complex, which Neisseria species is more likely to become disseminated?a) Nei…
Published	12/09/2024	Which of the following is a common symptom of Neisseria gonorrhoeae infection in men?a) Urethritisb) Pelvic inflammatory diseasec) Meningitisd) Skin r…
Published	12/09/2024	What is the hallmark symptom of pertussis (whooping cough)?a) A productive cough with green sputumb) Paroxysms of violent coughing followed by a loud …
Published	12/09/2024	Which of the following groups is at the highest risk of death from pertussis?a) Elderly individuals over 65b) Infants under 1 year of agec) Adolescent…
Published	12/09/2024	What is one of the major virulence factors of Bordetella pertussis?a) Coagulaseb) Pertussis toxinc) Alpha-toxind) M protein
Published	12/09/2024	Which of the following is caused by the adenylate cyclase toxin of Bordetella pertussis?a) Inhibition of phagocytosis and the oxidative burstb) Direct…
Published	12/09/2024	What is a typical systemic laboratory feature in infants with pertussis?a) Leukopeniab) Lymphocytosisc) Thrombocytopeniad) Eosinophilia
Published	12/09/2024	In pertussis, what causes the sustained lymphocytosis in infants?a) Increased production of lymphocytes in the bone marrowb) Inhibition of lymphocyte …
Published	12/09/2024	What morphological feature can be observed in a peripheral smear of an infant with pertussis?a) Large immature lymphocytes with irregular shapesb) Sma…
Published	12/09/2024	Which of the following is a common histopathological feature in severe cases of pertussis?a) Consolidation of lung tissueb) Bronchial mucosal erosion …
Published	12/09/2024	Pseudomonas aeruginosa is most commonly associated with infections in which of the following populations?a) Healthy young adultsb) Individuals with cy…
Published	12/09/2024	What makes Pseudomonas aeruginosa infections difficult to treat?a) The bacteria produce toxins that kill antibioticsb) The bacteria are often resistan…
Published	12/09/2024	What is a common cause of infection in people with extensive skin burns caused by Pseudomonas aeruginosa?a) Meningitisb) Sepsisc) Endocarditisd) Pneum…
Published	12/09/2024	Which of the following is a characteristic feature of Pseudomonas aeruginosa exotoxin A?a) It inhibits cell wall synthesisb) It disrupts DNA replicati…
Published	12/09/2024	What is a histological feature of necrotizing pneumonia caused by Pseudomonas aeruginosa?a) Striking pale necrotic centers with red, hemorrhagic perip…
Published	12/09/2024	What is ecthyma gangrenosum associated with in Pseudomonas aeruginosa infections?a) Acute bacterial endocarditisb) Skin lesions in patients with skin …
Published	12/09/2024	In Pseudomonas aeruginosa infection, what histopathological finding is seen in blood vessels?a) Caseous granulomasb) Coagulative necrosis of host cell…
Published	12/09/2024	Mycobacterium species are characterized by which of the following unique features?a) They are anaerobic and do not require oxygen for growthb) They ha…
Published	12/09/2024	What is the primary pathogen responsible for most cases of tuberculosis?a) M. bovisb) M. lepraec) M. tuberculosisd) M. avium
Published	12/09/2024	How does M. tuberculosis evade the immune system during infection of macrophages?a) By rapidly killing the macrophageb) By blocking phagosome-lysosome…
Published	12/09/2024	Which receptor is involved in the phagocytosis of M. tuberculosis by macrophages?a) Fc receptorsb) Mannose-binding lectinc) CD4 receptorsd) TLR4
Published	12/09/2024	What occurs during the earliest stage of primary tuberculosis (<3 weeks) in non-sensitized individuals?a) The bacteria are rapidly cleared by the i…
Published	12/09/2024	What is a common route of transmission for M. bovis that causes tuberculosis?a) Airborne transmission via respiratory dropletsb) Drinking milk contami…
Published	12/09/2024	What is the characteristic cell wall component of Mycobacterium that contributes to its acid-fastness?a) Peptidoglycanb) Mycolic acidc) Lipopolysaccha…
Published	12/09/2024	Which of the following pathogen-associated molecular patterns (PAMPs) from M. tuberculosis binds to TLR2 on innate immune cells?a) Unmethylated CpG nu…
Published	12/09/2024	The differentiation of Th1 cells during a M. tuberculosis infection depends on which of the following interleukins (IL)?a) IL-4 and IL-10b) IL-12 and …
Published	12/09/2024	What is the primary mediator that activates macrophages to kill M. tuberculosis during a Th1 immune response?a) TNF-αb) IFN-γc) IL-4d) IL-2
Published	12/09/2024	Granulomatous inflammation in tuberculosis is orchestrated by which type of immune cell?a) Th2 cellsb) Th1 cellsc) B cellsd) NK cells
Published	12/09/2024	Which of the following is a characteristic feature of the granulomatous response to M. tuberculosis?a) Formation of eosinophilic abscessesb) Different…
Published	12/09/2024	Which of the following best describes the typical presentation of primary tuberculosis?a) Rapid progression to cavitary lesions with systemic symptoms…
Published	12/09/2024	Which clinical feature is most commonly associated with secondary tuberculosis?a) Pleural effusion and consolidation of the lower lobesb) Extensive ca…
Published	12/09/2024	In a previously sensitized individual, reactivation of M. tuberculosis typically leads to which of the following?a) Immediate resolution of the infect…
Published	12/09/2024	Where in the lungs does primary tuberculosis most commonly begin?a) Upper part of the upper lobe or lower part of the lower lobeb) Lower part of the u…
Published	12/09/2024	What is the characteristic lesion formed in the lungs during primary tuberculosis called?a) Ghon complexb) Granulomac) Ghon focusd) Caseous granuloma
Published	12/09/2024	What occurs at the center of the Ghon focus during primary tuberculosis?a) Formation of granulomasb) Caseous necrosisc) Fibrosis and calcificationd) C…
Published	12/09/2024	What is the term used to describe the combination of parenchymal lung lesions and nodal involvement in primary tuberculosis?a) Ghon focusb) Ghon compl…
Published	12/09/2024	What histological feature is characteristic of active tuberculosis lesions?a) Formation of dense fibrous tissueb) Caseating and noncaseating granuloma…
Published	12/09/2024	What is typically found at the center of granulomas in active tuberculosis lesions?a) Hyperplastic epitheliumb) Multinucleated giant cellsc) Purulent …
Published	12/09/2024	How do granulomas in immunocompromised individuals with tuberculosis differ from those in healthy individuals?a) They have no inflammatory cellsb) The…
Published	12/09/2024	Where do initial lesions of secondary tuberculosis typically form in the lungs?a) In the upper parts of the lower lobeb) Close to the apical pleurac) …
Published	12/09/2024	What is the appearance of the initial lesion in secondary tuberculosis?a) Red and hemorrhagicb) Gray-white to yellow, with caseation and peripheral fi…
Published	12/09/2024	What happens to the initial parenchymal focus of secondary tuberculosis in immunocompetent individuals?a) It progresses to miliary tuberculosisb) It u…
Published	12/09/2024	What histological feature is commonly seen in the active lesions of secondary tuberculosis?a) Dense fibrotic tissue with no inflammatory cellsb) Coale…
Published	12/09/2024	What typically occurs in localized, apical, secondary pulmonary tuberculosis?a) Complete resolution without scarringb) Fibrosis leading to fibrocalcif…
Published	12/09/2024	What occurs in progressive pulmonary tuberculosis, particularly in older adults and immunosuppressed individuals?a) Healing of the apical lesion with …
Published	12/09/2024	What is characteristic of miliary pulmonary tuberculosis?a) Large cavitary lesions with visible blood vesselsb) Small, yellow-white consolidation foci…
Published	12/09/2024	Where is systemic miliary tuberculosis most commonly seen?a) In the lungs onlyb) In the liver, bone marrow, spleen, adrenals, meninges, kidneys, and o…
Published	12/09/2024	Where can isolated tuberculosis appear due to hematogenous seeding?a) Lungs onlyb) Kidneys, meninges, adrenals, bone, fallopian tubes, and vertebraec)…
Published	12/09/2024	What is the most frequent presentation of extrapulmonary tuberculosis?a) TB meningitisb) Lymphadenitis, commonly in the cervical region ("scrofula")c)…
Published	12/09/2024	Which condition is associated with Pott's disease in isolated tuberculosis?a) Adrenal tuberculosisb) Bone (osteomyelitis)c) Meningitisd) Fallopian tub…
Published	12/09/2024	What is the primary temperature range at which M. leprae proliferates?a) 37-40°Cb) 32-34°Cc) 28-30°Cd) 22-25°C
Published	12/09/2024	Which of the following best describes tuberculoid leprosy?a) Severe, with widespread skin nodules and loss of sensationb) Less severe, with dry, scaly…
Published	12/09/2024	What immune response is associated with tuberculoid leprosy?a) Weak Th1 response and Th2 responseb) Strong Th1 response with IL-2 and IFN-γ production…
Published	12/09/2024	Which of the following best characterizes lepromatous leprosy?a) A mild form with a Th1 responseb) Severe, with symmetric skin thickening, nodules, an…
Published	12/09/2024	What causes the nerve damage seen in lepromatous leprosy?a) Direct damage to the Schwann cells by M. lepraeb) Inflammatory cytokine release from Th1 c…
Published	12/09/2024	In which type of leprosy is M. leprae present in the sputum and blood in advanced cases?a) Tuberculoid leprosyb) Lepromatous leprosyc) Borderline lepr…
Published	12/09/2024	Which of the following is characteristic of tuberculoid leprosy?a) Symmetric skin lesions with extensive bacilli presentb) Large aggregates of lipid-l…
Published	12/09/2024	What is the primary complication associated with tuberculoid leprosy due to nerve involvement?a) Skin cancerb) Chronic skin ulcers due to traumac) Vis…
Published	12/09/2024	Why are bacilli almost never found in tuberculoid leprosy lesions?a) The bacilli are killed by the body's strong immune responseb) The bacilli are con…
Published	12/09/2024	Which of the following best describes lepromatous leprosy?a) Characterized by localized skin lesions and minimal bacterial involvementb) Involves larg…
Published	12/09/2024	What is a hallmark feature of lepromatous leprosy as the disease progresses?a) Development of "leonine facies" due to coalescing nodular lesionsb) Dec…
Published	12/09/2024	What does the term paucibacillary leprosy refer to in the context of tuberculoid leprosy?a) Leprosy with a high bacterial loadb) Leprosy with few to n…
Published	12/09/2024	Which areas of the body are typically not affected in lepromatous leprosy?a) Skin, peripheral nerves, eyes, upper airwaysb) CNS and vital organsc) Kid…
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