MIC 401 EXAM 4 QUESTIONS WITH VERIFIED SOLUTIONS LATEST UPDATE 2026

MIC 401 EXAM 4 QUESTIONS WITH VERIFIED SOLUTIONS LATEST UPDATE 2026 Mycobacterium characteristics - Answers -obligate aerobes -non-motile -slow growth rate -mycolic acid layer M. tuberculosis - Answers causes tuberculosis, can be acute or chronic, transmitted by infectious aerosols pulmonary tuberculosis infection - Answers -inhalation -phagocytosed by alveolar macrophages -inhibition of phagosome-lysosome fusion -bacterial growth within macrophages -macrophage burst to release more bacteria granuloma - Answers bacteria and infected macrophages surrounded by healthy immune cells caseous necrosis - Answers degeneration and death of tissue with a cheese-like appearance ghon focus - Answers nodules formed and contained in the lungs Ghon complex - Answers Ghon focus and the additional granulomas that develop through the lymph channels (typically lower lobes of lungs) latent tuberculosis - Answers -most common form -infected, but not contagious -do not feel sick -normal chest x-ray and sputum test -risk groups: young, old, immunocompromised active tuberculosis - Answers granuloma ruptures, coughing can be infectious, high mortality if untreated Extrapulmonary Tuberculosis - Answers infection spreads outside of the lungs, see in immunocompromised and children Miliary TB - Answers 20% of extrapulmonary cases, speckled lung, high mortality Multi-drug resistant TB - Answers resistant to at least one commonly used antibiotic extensively-drug resistant TB - Answers resistant to isoniazid and rifampin and most alternative drugs -requires 2 years of treatment BCG vaccine - Answers treatment for TB, but lots of variability based on geopgraphic region M. avium - Answers -similar to TB -swelling of neck lymph node in kids -can usually clear infection on own -AIDS patients are high risk M. leprae - Answers causes leprosy -low pathogenicity -difficult to grow (armadillo foot pads) -we see genome reduction leprosy - Answers Granulomatous disease of peripheral nerves and mucosa of upper respiratory tract -invades Schwann cells of PNS Tuberculoid leprosy - Answers -paucibacillary form -Th1 mediated response: cytotoxic T cells -localized infection -self-limiting Lepromatous leprosy - Answers -multibacillary form -Th2 mediated response: humoral B cells -associated with disfigurement -irreversible peripheral damage leprosy risk factors - Answers -immunocompromised -malnourished Mycoplasma characteristics - Answers -small, simplest self-replicating bacteria -surface parasites -lack biosynthetic abilities -pleomorphic -no cell well -fried egg colony appearance M. pneumoniae - Answers causes primary atypical pneumonia -transmitted by aerosol droplets -typically self resolves M. pneumonia infection - Answers -inhalation -P1 protein binds sialic acid receptor -tight adherence -replication and colonization causes cilliostasis M. pneumoniae risk factors - Answers -children and young adults -crowded conditions -summer and fall M. pneumoniae immune response - Answers requires specific antibody production of IgM followed by IgG Tetrazolium reduction test - Answers if compound is present, test is positive for M. pneumoinae cold agglutination test - Answers expose RBC to cold temp and look for clumping, this is linked to mycoplasma infection M. hominis - Answers causes PID, postpartum fever, and vaginitis in women -adheres to urogenital epithelium -transmitted by sexual contact or vertical -strong correlation to malignant cancer formation M. genitalium - Answers causes urethritis in men and cervicitis and pelvic inflammation in women -colonizes ciliated epithelial cells of urogenital tract -can be asymptomatic -detection is difficult Legionella characteristics - Answers -gram negative pleomorphic bacilli -silver stains -requires cysteine for growth -aerobic -beta-lactamase positive L. pneumophila - Answers Legionnaires' disease and Pontiac fever -transmitted through water aerosols -destruction of macrophages legionella containing vacuole - Answers bacteria is phagocytosed and uses type 4 secretion system Type 4 secretion system - Answers punch a hole in the vacuole membrane to send out molecules to interfere with lysosomes (used by legionella) Legionella risk factors - Answers middle-age or elderly persons, cigarette smokers, chronic lung disease, immunocompromised Fungal characteristics - Answers -eukaryotic -phospholipid bilayer membrane with ergosterol -cell wall with chitin Pneumocytis spp - Answers only species that does not have chitin in its cell wall hyphae - Answers long, thin filaments that form the basic structural unit of fungi Mycelium - Answers mass of hyphae septum - Answers the wall that divides cells fungal drug targets - Answers -ergosterol and its biosynthetic pathway -cell wall -cytosine deaminase Classes of fungi - Answers Chytridiomycota Zygomycota Ascomycota Basidiomycota Deuteromycota Dermatophytes - Answers keratinolytic fungi causes ringworm Tinea - Answers ringworm, infection of keratinized tissues tinea capitis - Answers ringworm of the scalp tinea corporis - Answers ringworm of the body tinea cruris - Answers jock itch tinea pedis - Answers athlete's foot Pytriasis versicolor - Answers superficial infection of the skin caused by Malassezia -tan to brown, scaly patches primarily on chest and back -found it area of sebaceous glands Malassezia - Answers dimorphic, lipophilic fungus Chron's diease - Answers has a correlation with Malassezia -CARD 9 allele associated with inflammation cascade onchymycosis - Answers fungal infection of the nail Candida albicans - Answers causes finger onchomycosis Trichophyton rubrum - Answers causes toe onchomycosis candida species characteristics - Answers yeast-like cells, pseudohyphae and true hyphae, part of normal flora, found in hospital settings, grown on CHROMagar Muco-cutaneous candidiasis - Answers -arises from overgrowth of normal flora -superficial infection -can result from long-term antibiotic use Disseminated candidiasis - Answers -candida enters blood stream through gut (leaky gut) -will colonize intravenous catheters -presents as non-specific sepsis Aspergillus characteristics - Answers -looks like a sprinkler -conidia -very small -polarized growth -fuzzy morphology conidia - Answers •Vehicle for environmental dissemination •Metabolically inactive •Dessication resistant •UV resistant •Heat resistant •Hydrophobic polarisome - Answers coordinates endocytosis and exocytosis Spitzenkorper - Answers coordinates delivery of vessicles fundamental role of filamentous fungi - Answers recycling of environmental carbon and nitrogen A. fumigatus - Answers thermophilic fungi that causes infection of lungs aspergilloma - Answers fungus ball that colonizes in a healed lung scar or abscess from a previous disease Allergic bronchopulmonary aspergillosis (ABPA) - Answers colonization of the lung resulting in chronic inflammation and lung fibrosis Invasive aspergillosis - Answers often disseminates hematogenously and can spread anywhere angioinvasion - Answers Penetration of arteries or veins by pathogenic organisms to gain access to the circulatory system. Who is most likely to have an invasive aspergillus infection? - Answers patients with leukemia and profound neutropenia cryptococcus neoformans characteristics - Answers -yeast cells -thick polysaccharide capsule -titan cells -intracellular growth titan cells - Answers giant cells (polyploid) that c. neoformans transitions to c. neoformans infection - Answers -lung is initial portal of entry -infection can be cleared, become latent, or disseminate -can cause pneumonia and meningoencephalitis -skin and eye infection if disseminates vomocytosis - Answers non-lytic exocytosis of C. neoformans dragocytosis - Answers cell to cell transfer of C. neoformans thermal dimorphism - Answers grow as molds at 25°C and as yeasts at 37°C Blastomyces dermatitidis - Answers -extracellular yeast -endemic to upper midwest Histoplasma capsulatum - Answers -intracellular yeast -endemic to ohio and Mississippi river valleys Coccioides immitis - Answers -extracellular spherioles -endemic to San Joaquin Valley of Southwest biological parasite - Answers An organism that grows, feeds, and is sheltered on or in a host organism to the detriment of that host. Medical Parasite - Answers organisms that causes disease in humans -historically not including bacteria, fungi, or viruses definitive host - Answers Host in which the obligate sexual stage of a parasite life cycle occurs. intermediate host - Answers Host in which non-sexual reproduction or development occurs. incidental host - Answers Is not an obligate part of the parasite life cycle direct transmission - Answers via exchange of bodily fluids ingestive transmission - Answers oral infection by a dormant cyst or egg in food or environment protozoa - Answers -An environmentally stable non-replicating form (fecal/oral transmission) -or a slowly replicating tissue form (food borne) helminthes - Answers a dormant juvenile (larval) form typically embedded in host tissue invasive transmission - Answers direct penetration of skin vector transmission - Answers transmission of an active non-replicating form by a blood-sucking arthropod maternal transmission - Answers trans-placental to a fetus in utero