Infectious Module Cheatsheet

Cheatsheet Content

I. General Microbiology & Infectious Diseases Not Transmissible Infection: Botulism MATS Hint: Intoxication, not infection; pre-formed toxin from $C$. $botulinum$. Stabilization of Heat Sensitive Instruments: Ethylene Oxide MATS Hint: Cold sterilization gas for heat-labile items like plastics and optics. Diagnosis of Polio Virus: Isolation of virus from stool and throat swab MATS Hint: Virus is shed in feces and oropharyngeal secretions. Black Eschar on Hand: $B$. $Anthracis$ MATS Hint: Cutaneous anthrax hallmark; painless ulcer with black necrotic center. $H$. $pylori$ produces urease: leads to gastric ulcer and can cause eye disease (e.g., MALT lymphoma) MATS Hint: Enzyme that produces ammonia, damaging gastric epithelium. Bacterial Toxin that $\uparrow$ cAMP: Cholera toxin MATS Hint: ADP-ribosylation of $G_s$ protein, causing perpetual cAMP production. Dental Caries: $Streptococcus$ $mutans$ MATS Hint: Converts sucrose to lactic acid and produces glucans for plaque. Granuloma Formation is Hallmark of: Chronic inflammation MATS Hint: Macrophages, epithelioid cells, giant cells; seen in TB, sarcoidosis. Helminths that penetrate skin: $Necator$ $americanus$ MATS Hint: Hookworm; filariform larvae penetrate skin, often through feet. Diagnosis of $Taenium$ $Solium$: Proglottids in stool MATS Hint: Identification of gravid proglottids or eggs in feces. Toxins in Peanuts: Aflatoxin MATS Hint: Produced by $Aspergillus$ species; hepatotoxic and carcinogenic. Mediator for Chemotaxis of Neutrophils: C5a MATS Hint: Anaphylatoxin; potent chemotactic factor for neutrophils. Function of APC: APC presents antigen, does not downregulate growth signals. MATS Hint: Antigen-Presenting Cell; presents antigen to T-cells via MHC. Lyme Disease: Caused by a spirochete transmitted by ticks. Answer: $Borrelia$ $burgdorferi$ MATS Hint: Spirochete transmitted by $Ixodes$ tick; causes erythema migrans. $gp120$ of HIV: interaction with CD4 cells Answer: Glycoprotein for attachment MATS Hint: Viral surface protein binds to CD4 receptor on T-cells. Symptoms of TB: Cough with hemoptysis, low grade fever, weight loss MATS Hint: Classic constitutional symptoms ("consumption"). Innate Immunity: Antibodies are not produced MATS Hint: Non-specific, first line defense; no immunological memory. Macrophage Function: Kill microbes and present antigen MATS Hint: Phagocytosis, antigen presentation via MHC II, cytokine release. Infective Form of Mosquito in Human: Sporozoite MATS Hint: Form injected by $Anopheles$ mosquito; travels to liver. $Toxoplasma$ $gondii$: Hydrocephalus MATS Hint: Congenital infection can cause intracranial calcifications and hydrocephalus. Exudate: Edema formation MATS Hint: Protein-rich fluid in acute inflammation due to increased vascular permeability. Ulcer: Disruption of epithelial lining with acute or chronic inflammation MATS Hint: Defect in the surface of an organ/tissue. Male Sterility: Klinefelter Syndrome MATS Hint: $47,XXY$ karyotype; hypogonadism, gynecomastia, infertility. Hydrops Fetalis with Hyperbilirubinemia: Kernicterus MATS Hint: Unconjugated bilirubin deposition in basal ganglia of newborns. Decreased Albumin Synthesis: Liver disease MATS Hint: Hepatocyte dysfunction leads to low albumin and edema. Koplik's Spot: Clinical feature of Measles MATS Hint: Pathognomonic for Measles (Rubeola); appear before rash. Serotypes of Dengue Virus: 4 MATS Hint: Four distinct serotypes (DENV-1, 2, 3, 4); infection with one does not confer immunity to others. Opportunistic Infection of AIDS: Occurs when CD4 cell count is below $200/cm^3$ MATS Hint: Critical threshold for AIDS-defining opportunistic infections. $E$. $coli$ (Enterotoxigenic): Causes acute watery (secretory diarrhea) MATS Hint: ETEC - Heat-labile (LT) and heat-stable (ST) toxins $\uparrow$ cAMP/cGMP. $Enterobacter$: Is gram –ve motile rod MATS Hint: Nosocomial pathogen; intrinsically resistant to ampicillin. $Pseudomonas$: Produces fruity aroma on culture MATS Hint: Grape-like odor; oxidase-positive, non-lactose fermenter. $Haemophilus$ $influenza$: Require X & V factor for growth MATS Hint: X factor = hemin, V factor = NAD; grows on chocolate agar. Correctly Matched: $Treponema$ $pallidum$ causes syphilis MATS Hint: Spirochete; cannot be cultured; diagnosed by serology (RPR/VDRL, FTA-ABS). Fungi: Cell membrane contains ergosterol MATS Hint: Target of azole and polyene antifungal drugs. Most Common Risk Factor for Chronic Obstructive Pulmonary Disease (COPD): Tobacco smoke MATS Hint: Cigarette smoking is the primary cause of COPD. $Mycobacterium$: Virulence factor for Cord factor MATS Hint: Trehalose dimycolate; inhibits phagolysosome fusion, causes cording. $Staphylococcus$ $aureus$: Most common cause of pyogenic osteomyelitis. MATS Hint: Most common cause in all age groups due to trauma or hematogenous spread. $Pneumococcus$: Most common cause of nature purulent meningitis in infants and children. MATS Hint: $S$. $pneumoniae$ is a leading cause of bacterial meningitis in children and adults. Amoebiasis: Laboratory diagnosis relied on isolation of cyst in the stool sample. MATS Hint: Microscopic examination of stool for cysts/trophozoites is primary. Cysts of $Entamoeba$: Sensitive and cannot survive by boiling. MATS Hint: Heat kills cysts; boiling water is effective. Protozoa: Multiply in host in several hours. MATS Hint: Replication time varies, but many protozoa have rapid multiplication. Malaria: Fatal in all ages (non-immune) but severe in children MATS Hint: Infants and young children are at high risk for severe malaria. Largest Intestinal Round Worm: $Ascaris$ $lumbricoides$. MATS Hint: Adult worms can be up to 35 cm long. Scotch Tape Test: Done to diagnose pinworm infection. MATS Hint: $Enterobius$ $vermicularis$; eggs are laid perianally, detected by tape test. Hot Air Oven Sterilization Temperature: $160^\circ C$. MATS Hint: Dry heat sterilization at $160^\circ C$ for 2 hours. Innate Host Defense: 1st Line of defense. MATS Hint: First line: skin, mucous membranes, secretions. Differential Culture Medium: MacConkey agar. MATS Hint: Lactose fermentation differentiates gram-negative bacteria. Endotoxin: Toxic portion of molecule is lipid A. MATS Hint: Lipid A is the toxic component of LPS in gram-negative bacteria. Flagellar Basal Body of Gram Negative Bacteria: Possesses four rings. MATS Hint: Gram-negative: 2 in plasma membrane, 2 in peptidoglycan and outer membrane. Characteristic Shape of Bacteria: Maintained by peptidoglycans. MATS Hint: Cell wall provides shape and rigidity. Eukaryotes: Usually has introns. MATS Hint: Eukaryotic genes have introns and exons. Bacterial Structure for Antibiotic Action: Cell wall. MATS Hint: Penicillins, cephalosporins target cell wall synthesis. Staining Tissue with Best Carmine: Suggests glycogen. MATS Hint: Carmine stains glycogen; PAS (Periodic acid-Schiff) is also used. Formaldehyde: Is used 37% aqueous solution. MATS Hint: Formalin; used for disinfection and tissue preservation. $Clostridium$ $tetani$: Produces neurotoxin. MATS Hint: Tetanospasmin toxin causes spastic paralysis by blocking inhibitory neurotransmitters. $Streptococci$ beta hemolytic group A: Produces damage heart valves. MATS Hint: $S$. $pyogenes$ can cause Rheumatic Heart Disease via molecular mimicry. Triple Sugar Iron (TSI) Media: Slant alkaline but acidic, gas and blackening in media organism will be $Shigella$. MATS Hint: Alkaline slant, acid butt, no gas, no $H_2S \rightarrow Shigella$. $Bacteria$ $fragilis$: Can produce intra abdominal abscesses. MATS Hint: Anaerobic, gram-negative rod; common in mixed abdominal infections. $Mycobacterium$ $leprae$: Particularly found in mucous membrane of nasal septum. MATS Hint: Acid-fast bacillus; causes Leprosy; found in cool body areas. Hepatitis A Virus: Initially identified in blood; destroyed in boiling water for 5 minutes. MATS Hint: RNA picornavirus; transmitted fecal-oral route; inactivated by heat/chlorine. Poliomyelitis: Vaccine contains live attenuated virus. MATS Hint: Sabin vaccine is live oral; Salk is inactivated injectable. $Mucor$: Invades and proliferates in the walls of blood vessels producing thrombosis. MATS Hint: Angioinvasive fungi; broad, aseptate hyphae; causes Rhinocerebral mucormycosis. $Pneumococcus$: Sensitive to optochin disc. MATS Hint: Optochin sensitive and bile soluble; distinguishes from other alpha-hemolytic strep. Aerobic $Actinomyces$: Typical finding is sulfur granule in pus. MATS Hint: $Actinomyces$ $israelii$; gram-positive, branching rods; forms sulfur granules in pus. Urine Detailed Report: Main microscope feature of UTI is pus cells. MATS Hint: Pyuria (WBCs in urine) is a key indicator of UTI. Common Microorganism Responsible for Acute Pyelonephritis: $E$. $coli$. MATS Hint: Uropathogenic $E$. $coli$ (UPEC) is the most common cause. Main Cause of Prerenal Azotemia or Uremia: Dehydration. MATS Hint: Reduced renal perfusion before damage to kidney itself. Most Common Malignant Tumor of Kidney: Clear cell carcinoma. MATS Hint: Renal Cell Carcinoma; most common type is clear cell. Cause of Osteoporosis: Post menopausal age. MATS Hint: Estrogen deficiency accelerates bone resorption. Wound Growth Factors: VEGF and FGF promote angiogenesis. MATS Hint: VEGF is the primary mediator of angiogenesis (new blood vessel formation) in healing tissue. Growth Factors and Cytokines in Tissue Repair: Regulate cell proliferation, migration, differentiation, and ECM production. MATS Hint: Growth factors (e.g., PDGF, FGF, TGF-$\beta$) and cytokines coordinate all phases of the healing process. Common Factors Impeding Healing: Poor blood supply, malnutrition, diabetes, prolonged inflammation. MATS Hint: Local (ischemia) and systemic (diabetes, nutrition) factors can delay wound healing. Scar Formation: Fibroblast deposit collagen in ECM, replacing granulation tissue. MATS Hint: Collagen deposition and remodeling by fibroblasts transform granulation tissue into a fibrous scar. Gram-Positive Cocci Hemolysis: Beta-hemolytic streptococci ($Streptococcus$ $pyogenes$ and $Streptococcus$ $agalactiae$). MATS Hint: Beta-hemolytic streptococci (Group A and B) produce enzymes that completely lyse RBCs, clearing the agar. Media for Hemolysis: Blood agar. MATS Hint: Blood agar is the standard medium for observing hemolysis patterns (alpha, beta, gamma). Complete Hemolysis: Beta-hemolysis. MATS Hint: Beta-hemolysis appears as a clear zone around colonies due to complete RBC lysis. Gram-Negative Diplococci: $Neisseria$ $gonorrhoeae$. MATS Hint: Gram-negative diplococci with flattened adjacent sides; causes the sexually transmitted infection gonorrhea. Diseases Caused by $Neisseria$ $gonorrhoeae$: Gonorrhea, Neonatal conjunctivitis, pelvic inflammatory disease. MATS Hint: $N$. $gonorrhoeae$ causes urethritis, cervicitis, PID, and ophthalmia neonatorum in newborns. Node of Transmission (Women): Sexual, leading to Pelvic Inflammatory Disease (PID). MATS Hint: Ascending infection in women can lead to PID, causing infertility and ectopic pregnancy. Selective Media for $Neisseria$: Thayer-Martin Agar. MATS Hint: Thayer-Martin medium is a selective chocolate agar with antibiotics (VCNT) for isolating $Neisseria$ from mixed samples. Gram-Positive Bacilli with Spores: $Bacillus$ $Anthracis$. MATS Hint: Large, gram-positive, spore-forming rod; causes anthrax. II. Antimicrobial Agents Aminoglycosides (Neomycin): Binds to 30S ribosomal subunit, inhibiting protein synthesis. MATS Hint: Neomycin is an aminoglycoside that binds to the 30S ribosomal subunit, inhibiting protein synthesis. Aminoglycosides (Post-Antibiotic Effect): Lasts for several hours, allowing once-daily dosing. MATS Hint: Aminoglycosides have a significant Post-Antibiotic Effect (PAE), allowing for once-daily dosing regimens. Aminoglycoside as Luminal Amebicide: Paromomycin. MATS Hint: Paromomycin is a non-systemic aminoglycoside used orally to treat intestinal amoebiasis by acting directly on trophozoites in the gut lumen. Aminoglycoside for Bowel Surgery: Neomycin. MATS Hint: Neomycin is used orally for bowel preparation because it is poorly absorbed and reduces aerobic gram-negative flora. Tetracycline (Acne Treatment): Doxycycline, Minocycline. MATS Hint: Tetracyclines (e.g., doxycycline, minocycline) are first-line for inflammatory acne due to their anti-inflammatory and anti-bacterial effects against C. acnes. Tetracycline (Contraindications): Not first-line for tuberculosis. MATS Hint: Tetracyclines are not first-line for tuberculosis. First-line drugs are RIPE (Rifampin, Isoniazid, Pyrazinamide, Ethambutol). Tetracycline (Pregnancy): Avoided due to teeth discoloration and hyperplastic enamel in newborn. MATS Hint: Tetracyclines cross the placenta and bind to calcium in developing teeth and bones, causing permanent yellow-brown discoloration and enamel hypoplasia. Tetracycline (Children Not given due to deposition in calcifying tissue. MATS Hint: Tetracyclines are contraindicated in children under 8 due to binding to calcium in teeth and bones, causing discoloration and growth retardation. Minocycline (Absorption): Highest oral absorption rate. MATS Hint: Minocycline is the most lipophilic tetracycline, resulting in nearly complete oral absorption (95-100%). Doxycycline (Absorption): 95-100% oral absorption. MATS Hint: Doxycycline is well-absorbed orally (95-100%) and can be taken with food (except dairy and antacids). Tetracycline (New Blood Vessel Formation): Reduces new blood vessel formation. MATS Hint: Tetracyclines (especially doxycycline) inhibit matrix metalloproteinases (MMPs), which reduces angiogenesis and is useful in treating rosacea and periodontitis. Chloramphenicol (Gray Baby Syndrome): Characterized by pallor, cyanosis, and even death. MATS Hint: Chloramphenicol causes "Gray Baby Syndrome" in neonates due to immature liver glucuronidation, leading to toxic accumulation and cardiovascular collapse. Chloramphenicol (Bone Marrow Suppression): Causes dose-dependent (reversible) and idiosyncratic aplastic anemia (irreversible and fatal). MATS Hint: Chloramphenicol causes dose-dependent bone marrow suppression (reversible) and idiosyncratic aplastic anemia (irreversible and fatal). Chloramphenicol (Infant Toxicity): Due to accumulation of antibiotic given at higher doses. MATS Hint: Classic presentation of Chloramphenicol toxicity in a neonate ("Gray Baby Syndrome"). Chloramphenicol (Pancytopenia): Fatal pancytopenia. MATS Hint: Chloramphenicol is associated with idiosyncratic aplastic anemia, leading to fatal pancytopenia, which is not dose-related. Chloramphenicol (Typhoid Fever): Drug of choice. MATS Hint: Chloramphenicol was the classic drug for typhoid fever, though now Ceftriaxone or Fluoroquinolones are often preferred due to resistance. Clarithromycin ($H$. $pylori$ Eradication): Most commonly used macrolide. MATS Hint: Clarithromycin is a key component of triple therapy for $H$. $pylori$ eradication (with a PPI and Amoxicillin/Metronidazole). Erythromycin (Effectiveness): Not much effective in $H$. $influenzae$. MATS Hint: Erythromycin has poor activity against $Haemophilus$ $influenzae$. Clarithromycin (Activity): More active against $Mycobacterium$ $avium$. MATS Hint: Clarithromycin is a primary drug for prophylaxis and treatment of $Mycobacterium$ $avium$ complex (MAC) in immunocompromised patients. Trimethoprim-Sulfamethoxazole (Opportunistic Infections): Effective against $Toxoplasmosis$ in AIDS patients. MATS Hint: TMP-SMX is the first-line treatment and prophylaxis for $Toxoplasma$ $gondii$ encephalitis in HIV/AIDS patients. Co-trimoxazole: Is an antibiotic. MATS Hint: Co-trimoxazole is a combination of two antibiotics (Trimethoprim + Sulfamethoxazole). Trimethoprim (Antimetabolite): Is an Antimetabolite. MATS Hint: Trimethoprim is a dihydrofolate reductase inhibitor, acting as an antimetabolite in the folate synthesis pathway. Sulfonamides (Phototoxicity): Side effect. MATS Hint: Sulfonamides can cause photosensitivity reactions, leading to severe sunburn after UV exposure. Sulfasalazine (Inflammatory Bowel Disease): Used to Rx inflammatory Bowel disease. MATS Hint: Sulfasalazine is a prodrug that delivers 5-aminosalicylic acid (5-ASA) to the colon, used for ulcerative colitis. Nalidixic Acid (1st Generation Quinolone): Is a 1st Generation Quinolone. MATS Hint: Nalidixic acid is the prototype of the first-generation quinolones, with narrow spectrum and use limited to UTIs. Norfloxacin (Least Active Fluoroquinolone): Against both gram-negative and gram-positive organisms. MATS Hint: Norfloxacin has the lowest potency and is not used for systemic infections due to poor tissue levels. Lomefloxacin (Photosensitivity): Reported by the use of. MATS Hint: Lomefloxacin is particularly associated with a high incidence of phototoxicity among the fluoroquinolones. Fluoroquinolones (Nucleic Acid Synthesis): Inhibit Nucleic acid synthesis. MATS Hint: Fluoroquinolones inhibit bacterial DNA gyrase (topoisomerase II) and topoisomerase IV. Fluoroquinolones (Antibacterial Properties): By inhibiting bacterial DNA synthesis. MATS Hint: By inhibiting DNA gyrase/topoisomerase, fluoroquinolones ultimately halt bacterial DNA replication. Trovafloxacin (Life-Threatening Infections): Reserved for treatment due to complete liver failure. MATS Hint: Trovafloxacin was severely restricted due to its association with rare but fatal idiosyncratic hepatotoxicity. Aminoglycosides (Curare-Like Effect): Seen with higher doses. MATS Hint: Aminoglycosides can inhibit acetylcholine release and post-synaptic sensitivity, leading to a curare-like neuromuscular blockade. Amikacin (Loss of Equilibrium and Auditory Damage): Most likely to cause. MATS Hint: All aminoglycosides cause ototoxicity, but Amikacin is particularly associated with vestibular (loss of equilibrium) and auditory damage. Streptomycin (Plague Treatment): Useful in the treatment of. MATS Hint: Streptomycin is a first-line drug for the treatment of plague caused by $Yersinia$ $pestis$. Aminoglycosides (Ototoxicity): Adverse effect. MATS Hint: Ototoxicity (vestibular and cochlear) and nephrotoxicity are the major dose-limiting adverse effects of aminoglycosides. Vancomycin (Synergistic): With Streptomycin. MATS Hint: The combination of a cell wall inhibitor (vancomycin) and an aminoglycoside (streptomycin) is synergistic against enterococci, especially in endocarditis. Aminoglycosides (Exclusions): Do not include Azithromycin. MATS Hint: Azithromycin is a macrolide antibiotic, not an aminoglycoside. Neomycin (Protein Synthesis Inhibitor): Acts as. MATS Hint: Neomycin is an aminoglycoside that binds to the 30S ribosomal subunit, inhibiting protein synthesis. Aminoglycosides (Post-Antibiotic Effect): Lasts for several hours. MATS Hint: Aminoglycosides have a significant Post-Antibiotic Effect (PAE), allowing for once-daily dosing regimens. Paromomycin (Luminal Amebicide): Aminoglycoside used as. MATS Hint: Paromomycin is a non-systemic aminoglycoside used orally to treat intestinal amoebiasis by acting directly on trophozoites in the gut lumen. Neomycin (Bowel Preparation): Used for elective bowel surgery. MATS Hint: Neomycin is used orally for bowel preparation because it is poorly absorbed and reduces aerobic gram-negative flora. Tetracycline (Acne): Drug of choice for treatment. MATS Hint: Tetracyclines (e.g., doxycycline, minocycline) are first-line for inflammatory acne due to their anti-inflammatory and anti-bacterial effects against C. acnes. Tetracycline (Infections): Not drug of choice for tuberculosis. MATS Hint: Tetracyclines are not first-line for tuberculosis. First-line drugs are RIPE (Rifampin, Isoniazid, Pyrazinamide, Ethambutol). Tetracycline (Pregnancy): Avoided due to teeth discoloration and hyperplastic enamel in newborn. MATS Hint: Tetracyclines cross the placenta and bind to calcium in developing teeth and bones, causing permanent yellow-brown discoloration and enamel hypoplasia. Tetracycline (Children Not given due to deposition in calcifying tissue. MATS Hint: Tetracyclines are contraindicated in children under 8 due to binding to calcium in teeth and bones, causing discoloration and growth retardation. Minocycline (Absorption): Highest oral absorption rate. MATS Hint: Minocycline is the most lipophilic tetracycline, resulting in nearly complete oral absorption (95-100%). Doxycycline (Absorption): 95-100% oral absorption. MATS Hint: Doxycycline is well-absorbed orally (95-100%) and can be taken with food (except dairy and antacids). Tetracycline (New Blood Vessel Formation): Reduces. MATS Hint: Tetracyclines (especially doxycycline) inhibit matrix metalloproteinases (MMPs), which reduces angiogenesis and is useful in treating rosacea and periodontitis. Chloramphenicol (Gray Baby Syndrome): Associated with. MATS Hint: Chloramphenicol causes "Gray Baby Syndrome" in neonates due to immature liver glucuronidation, leading to toxic accumulation and cardiovascular collapse. Chloramphenicol (Bone Marrow Suppression): Causes. MATS Hint: Chloramphenicol causes dose-dependent bone marrow suppression (reversible) and idiosyncratic aplastic anemia (irreversible and fatal). Chloramphenicol (Infant Toxicity): Due to accumulation. MATS Hint: Classic presentation of Chloramphenicol toxicity in a neonate ("Gray Baby Syndrome"). Chloramphenicol (Pancytopenia): Fatal. MATS Hint: Chloramphenicol is associated with idiosyncratic aplastic anemia, leading to fatal pancytopenia, which is not dose-related. Chloramphenicol (Typhoid Fever): Drug of choice. MATS Hint: Chloramphenicol was the classic drug for typhoid fever, though now Ceftriaxone or Fluoroquinolones are often preferred due to resistance. Clarithromycin ($H$. $pylori$ Eradication): Most commonly used macrolide. MATS Hint: Clarithromycin is a key component of triple therapy for $H$. $pylori$ eradication (with a PPI and Amoxicillin/Metronidazole). Erythromycin (Activity): Not much effective in $H$. $influenzae$. MATS Hint: Erythromycin has poor activity against $Haemophilus$ $influenzae$. Clarithromycin (Activity): More active against $Mycobacterium$ $avium$. MATS Hint: Clarithromycin is a primary drug for prophylaxis and treatment of $Mycobacterium$ $avium$ complex (MAC) in immunocompromised patients. Trimethoprim-Sulfamethoxazole (Opportunistic Infections): Effective against $Toxoplasmosis$ in AIDS patients. MATS Hint: TMP-SMX is the first-line treatment and prophylaxis for $Toxoplasma$ $gondii$ encephalitis in HIV/AIDS patients. Co-trimoxazole: Is an antibiotic. MATS Hint: Co-trimoxazole is a combination of two antibiotics (Trimethoprim + Sulfamethoxazole). Trimethoprim (Antimetabolite): Is an Antimetabolite. MATS Hint: Trimethoprim is a dihydrofolate reductase inhibitor, acting as an antimetabolite in the folate synthesis pathway. Sulfonamides (Phototoxicity): Side effect. MATS Hint: Sulfonamides can cause photosensitivity reactions, leading to severe sunburn after UV exposure. Sulfasalazine (Inflammatory Bowel Disease): Used to Rx. MATS Hint: Sulfasalazine is a prodrug that delivers 5-aminosalicylic acid (5-ASA) to the colon, used for ulcerative colitis. Nalidixic Acid (1st Generation Quinolone): Is a 1st Generation Quinolone. MATS Hint: Nalidixic acid is the prototype of the first-generation quinolones, with narrow spectrum and use limited to UTIs. Norfloxacin (Least Active Fluoroquinolone): Against both gram-negative and gram-positive organisms. MATS Hint: Norfloxacin has the lowest potency and is not used for systemic infections due to poor tissue levels. Lomefloxacin (Photosensitivity): Reported by the use of. MATS Hint: Lomefloxacin is particularly associated with a high incidence of phototoxicity among the fluoroquinolones. Fluoroquinolones (Nucleic Acid Synthesis): Inhibit Nucleic acid synthesis. MATS Hint: Fluoroquinolones inhibit bacterial DNA gyrase (topoisomerase II) and topoisomerase IV. Fluoroquinolones (Antibacterial Properties): By inhibiting bacterial DNA synthesis. MATS Hint: By inhibiting DNA gyrase/topoisomerase, fluoroquinolones ultimately halt bacterial DNA replication. Trovafloxacin (Life-Threatening Infections): Reserved for treatment due to complete liver failure. MATS Hint: Trovafloxacin was severely restricted due to its association with rare but fatal idiosyncratic hepatotoxicity. Aminoglycosides (Curare-Like Effect): Seen with higher doses. MATS Hint: Aminoglycosides can inhibit acetylcholine release and post-synaptic sensitivity, leading to a curare-like neuromuscular blockade. Amikacin (Loss of Equilibrium and Auditory Damage): Most likely to cause. MATS Hint: All aminoglycosides cause ototoxicity, but Amikacin is particularly associated with vestibular (loss of equilibrium) and auditory damage. Streptomycin (Plague Treatment): Useful in the treatment of. MATS Hint: Streptomycin is a first-line drug for the treatment of plague caused by $Yersinia$ $pestis$. Aminoglycosides (Ototoxicity): Adverse effect. MATS Hint: Ototoxicity (vestibular and cochlear) and nephrotoxicity are the major dose-limiting adverse effects of aminoglycosides. Vancomycin (Synergistic): With Streptomycin. MATS Hint: The combination of a cell wall inhibitor (vancomycin) and an aminoglycoside (streptomycin) is synergistic against enterococci, especially in endocarditis. Aminoglycosides (Exclusions): Do not include Azithromycin. MATS Hint: Azithromycin is a macrolide antibiotic, not an aminoglycoside. Neomycin (Protein Synthesis Inhibitor): Acts as. MATS Hint: Neomycin is an aminoglycoside that binds to the 30S ribosomal subunit, inhibiting protein synthesis. III. Parasitology Schistosoma: Parasite transmitted directly by larvae skin penetration. MATS Hint: Schistosome cercariae directly penetrate the skin of humans in water. $P$. $falciparum$: Exoerythrocytic stage is absent. MATS Hint: $Plasmodium$ $falciparum$ does not have a persistent exo-erythrocytic (hypnozoite) stage, so relapses do not occur. $P$. $vivax$: Preferably infects reticulocytes. MATS Hint: $Plasmodium$ $vivax$ has a preference for invading reticulocytes (young red blood cells). $P$. $vivax$: Has dormant liver stage. MATS Hint: $Plasmodium$ $vivax$ and $P$. $ovale$ form dormant hypnozoites in the liver. $P$. $malariae$: Longest incubation period. MATS Hint: $Plasmodium$ $malariae$ has the longest incubation period, which can be several weeks to months. $P$. $falciparum$: Shortest incubation period. MATS Hint: $Plasmodium$ $falciparum$ has the shortest incubation period, typically 9-14 days. $P$. $falciparum$ Malaria: All stages seen except schizont. MATS Hint: Mature schizonts of $P$. $falciparum$ are not typically seen in the peripheral blood smear because cytoadherence sequesters them in deep capillaries. Thin Blood Smear for Malaria: Used to identify type of parasite. MATS Hint: The thin blood smear is used for species identification of the malaria parasite based on detailed morphological features. Pinworm: $Enterobius$ $vermicularis$. MATS Hint: $Enterobius$ $vermicularis$ is the scientific name for the pinworm. $Echinococcus$ $granulosus$: Cestode Dog is definite host. MATS Hint: The definitive host for $Echinococcus$ $granulosus$ (causing hydatid disease) is the dog. $Toxoplasma$ $gondii$: Causes abortion, neonatal encephalitis, chorioretinitis, hepatosplenomegaly, fever, jaundice, and intracranial calcifications. MATS Hint: This is the classic presentation of congenital toxoplasmosis. IV. Pathology and Pathophysiology Type II Hypersensitivity Dysfunction without Cell Injury: Myasthenia Gravis. MATS Hint: Antibody-mediated dysfunction; anti-AChR antibodies block signal. Organ Transplant Antigen Recognition: HLA (Human Leukocyte Antigen). MATS Hint: Major Histocompatibility Complex (MHC) in humans; triggers rejection. Down's Syndrome Cause: Meiotic nondisjunction. MATS Hint: Trisomy 21 due to chromosomal nondisjunction. Carcinoma in Situ: Dysplastic changes involving full epithelial thickness. MATS Hint: Full-thickness dysplasia without invasion through basement membrane. Ascites in Gastro-Intestinal Pathology: Portal hypertension. MATS Hint: Increased pressure in portal venous system; common in cirrhosis. Generalized Edema in CHF: Impaired Venous return. MATS Hint: Increased hydrostatic pressure due to pump failure. Irreversible Injury (Characteristic Feature): Karyorrhexis. MATS Hint: Nuclear fragmentation; sign of cell death. Fas Receptor Triggers: FADD stimulates Caspase 8. MATS Hint: Extrinsic pathway of apoptosis; Death Domain signaling. Quellung Reaction: $S$. $pneumoniae$. MATS Hint: Capsular swelling reaction with specific antisera. Tinea Pedis (Athlete's Foot) and Jock Itch (Low): Warm and humid areas. MATS Hint: Dermatophyte fungi thrive in moist, occluded areas like groin. Keratomalacia: Vit A deficiency. MATS Hint: Corneal softening and ulceration due to severe Vitamin A deficiency. Secondary Dengue Fever: Breakbone fever/dengue hemorrhage. MATS Hint: Antibody-Dependent Enhancement (ADE) causes severe disease. Penicillin and Cephalosporin Action: Peptidoglycan. MATS Hint: Inhibit transpeptidase (PBP), blocking cell wall cross-linking. Cephalosporin (Mycoplasma): Doesn't affect Mycoplasma. MATS Hint: Lacks a peptidoglycan cell wall, the target of $\beta$-lactams. $S$. $pyogenes$ Virulence Factor (Red Rashes): Erythrogenic toxin. MATS Hint: Causes rash in Scarlet Fever; superantigen. $S$. $aureus$ Virulence Factor (Scalded Skin Syndrome): Exfoliatin. MATS Hint: Toxin that cleaves desmoglein-1 in the epidermis. Meningococcemia: Fever with purpura, hypotension. MATS Hint: $Neisseria$ $meningitidis$ sepsis; can cause Waterhouse-Friderichsen syndrome. Struvite Stone: $Proteus$. MATS Hint: Urease-positive bacterium; ammonia production creates alkaline urine. Benign Tumor (Growth Potential & Outcome): Limited growth potential and good outcome. MATS Hint: Non-invasive, no metastasis, often cured by excision. Pleomorphism: Variation in size and shape. MATS Hint: Cellular and nuclear variation; a feature of malignancy. Metastasis: Cells moved from one site to another. MATS Hint: Spread of a tumor to a distant site. Oxidative Stress: Decreased ATP and reversible injury. MATS Hint: Mitochondrial damage $\rightarrow$ ATP depletion $\rightarrow$ cellular swelling. T Lymphocytes (Self/Non-Self Distinction): Acquire ability at Thymus. MATS Hint: Site of T-cell maturation and positive/negative selection. Fungal Infections (Mycosis): Called mycosis. MATS Hint: General term for any fungal disease. M Protein of $Streptococcus$ $pyogenes$ and Muscle: Molecular mimicry. MATS Hint: Cross-reactivity between bacterial and host antigens; cause of Rheumatic Fever. Autoimmune Disease (Multiple Sclerosis): Possible cause is Hepatitis A virus. MATS Hint: Viral triggers are hypothesized for many autoimmune diseases. Polio Mellitus (Clinical Form): Most common is Abortive. MATS Hint: Minor illness (fever, malaise) is the most common presentation. Hepatitis B Virus Antigen (Diagnosis & Immunization): Surface antigen. MATS Hint: HBsAg indicates infection; antibody to it (anti-HBs) indicates immunity. Hepatitis C Virus (HCV) Induced Infection (Hepatocellular Carcinoma): Rate increased due to chronic inflammation. MATS Hint: Chronic inflammation and cirrhosis lead to HCC; direct viral oncoproteins also implicated. HIV Gene (Reverse Transcription Enzyme Protein): Encoded on Pol. MATS Hint: Pol gene encodes for reverse transcriptase, integrase, protease. Motile, Feeding, Reproducing Protozoa (Flexible Cell Membrane): Trophozoite. MATS Hint: Active, vegetative form of protozoa (e.g., $E$. $histolytica$, $Giardia$). Vaginal Discharge (Watery, Foul Smelling, Greenish, Itching, Burning): $Trichomonas$ $vaginalis$. MATS Hint: Flagellated protozoan; motile trophozoites on wet mount. Malarial Parasites (Relapses): Mostly seen with $P$. $vivax$ & $P$. $ovale$. MATS Hint: Have dormant hypnozoites in the liver causing relapses. Nematodes (Penetrate Skin): $Ancylostoma$ $duodenale$. MATS Hint: Hookworm; filariform larvae penetrate skin. Robertsonian Translocation: Fusion of two homologous chromosomes. MATS Hint: Robertsonian translocation is a fusion of two acrocentric chromosomes at the centromere, commonly involving chromosomes 14 and 21. Genetic Disease (Male to Male Transmission): Impossible in X-linked inheritance. MATS Hint: In X-linked inheritance, the father passes the X chromosome only to daughters, so affected fathers cannot pass the disease to sons. Breast Cancer (Metastatic Calcification): Widespread bony metastases lead to calcification of multiple organs. MATS Hint: Metastatic calcification occurs in normal tissues due to hypercalcemia, which can be caused by bone metastases from breast cancer. Myocardial Fibers (Irreversible Injury): Nuclei undergo karyorrhexis. MATS Hint: Karyorrhexis (nuclear fragmentation) is a sign of irreversible cell injury and necrosis. Prostate (Pathologic Change): Diffusely enlarged prostate due to Hyperplasia. MATS Hint: Benign prostatic hyperplasia (BPH) is a common cause of prostate enlargement in older men, characterized by an increase in the number of cells. Brain (Cystic Lesion): Liquefactive necrosis. MATS Hint: Liquefactive necrosis is typical in brain infarcts and bacterial infections, resulting in a cystic lesion. $Mycobacterium$ $tuberculosis$ (Pathologic Process): Caseation necrosis. MATS Hint: Caseous necrosis is a hallmark of tuberculosis, characterized by a cheesy, granular appearance. Leukocytes Migration (Firm Adhesion): Mediated by Integrins. MATS Hint: Integrins on leukocytes bind to adhesion molecules (e.g., ICAM-1) on endothelial cells, mediating firm adhesion. Tuberculosis Granuloma (Composition): Macrophages, lymphocytes, Langhans giant cells and necrosis. MATS Hint: Tuberculous granulomas are composed of epithelioid macrophages, Langhans giant cells, lymphocytes, and central caseous necrosis. Cat Dander Allergy (Nasal Congestion): Histamine. MATS Hint: Histamine is the primary mediator released in immediate (type I) hypersensitivity reactions, causing vasodilation, increased vascular permeability, and smooth muscle contraction. Neutrophils (Chemotactic Potential): C5a has greatest affinity. MATS Hint: C5a is one of the most potent chemotactic factors for neutrophils. Aspirin (Pain Reduction): Through Prostaglandins. MATS Hint: Aspirin inhibits cyclooxygenase (COX) enzymes, reducing the production of prostaglandins, which are involved in pain and inflammation. Cardiac Surgery (Heart Failure Cells): Chronic passive congestion of the lungs. MATS Hint: Heart failure cells are alveolar macrophages that have ingested hemosiderin, resulting from chronic pulmonary congestion (e.g., in left heart failure). Road Traffic Accident (Shock Type): Hypovolemic. MATS Hint: Hypovolemic shock results from a significant loss of blood or fluids, reducing circulating volume. Congestive Cardiac Failure (Dependent Edema): Increased hydrostatic pressure. MATS Hint: In heart failure, impaired venous return leads to increased hydrostatic pressure in the veins, causing fluid to leak into the interstitial space (edema). Cholecystectomy (Perfusion Defect): Hemorrhagic (red) infarct. MATS Hint: Pulmonary embolism typically leads to hemorrhagic (red) infarcts in the lung because of the dual blood supply and loose tissue. Septic Shock (Pathophysiology): Release of procoagulants and increase fibrinolysis leads to microvascular thrombosis. MATS Hint: In septic shock, there is activation of coagulation and inhibition of fibrinolysis, leading to microvascular thrombosis, not increased fibrinolysis. Infectious Agent (Communicable Disease): Illness caused by. MATS Hint: A communicable disease is one that can be transmitted from one host to another. Chain of Infection (Portal of Exit): Pathogen leaving the reservoir host. MATS Hint: The portal of exit is the path by which the pathogen leaves the reservoir (e.g., respiratory tract, blood, GI tract). Epidemic: Occurrence of more cases in a place (or population) and time than expected. MATS Hint: An epidemic is the occurrence of more cases of a disease than expected in a given area or among a specific group of people over a particular period of time.