Hepatitis (High-yield)
Parasitology 2: GI helminths (High-yield)
Infectious diseases that target red blood cells (High-yield)
Plasmodium (protozoa that causes malaria) Transmitted by female Anopheles mosquito. Lifecycle includes liver (exoerythrocytic) and blood (erythrocytic) stages. Vivax and P. ovale form dormant hypnozoites in liver—cause relapses. Falciparum infects all RBC stages—highest parasitemia and severity. Symptoms (fever, chills) correlate with RBC rupture during schizont release. Diagnosis of malaria Thick smear: Screening and parasite […]
Acute infectious diarrhea (High-yield)
Microbiome and antimicrobial stewardship (High-yield)
Microbiome basics Microbiome = all microbes + their genomes + the environment they occupy. Humans have ~38 trillion microbial cells (more than human cells). Major phyla: Firmicutes (Gram+ anaerobes) Bacteroidetes (Gram– anaerobes) Proteobacteria (Gram– facultative rods) Actinobacteria (Gram+ bacilli) Normal flora by site Carrier state: colonization with potential pathogen (e.g., S. aureus). Body site […]
Principles of microbiology laboratory diagnosis (High-yield)
Learning goals Compare direct examination, culture, serologic, and molecular methods for identifying microorganisms. Differentiate diagnostic approaches for bacteria vs. viruses. Understand how to select appropriate microbiologic diagnostic tests. Direct examination Uses stains (Gram, Acid-fast, fluorescent) to visualize organisms directly from specimens. Low sensitivity/specificity; risk of false positives/negatives. Gram stain: differentiates Gram-positive (purple) vs. Gram-negative […]
Pharmacology: Introduction to antimicrobial therapy (High-yield)
Learning goals Understand five mechanisms of antibiotic action Differentiate empiric vs. directed therapy Recognize bacterial resistance mechanisms Apply PK/PD principles: bacteriostatic vs. bactericidal, time vs. concentration dependence Mechanisms of action Cell Wall Synthesis Inhibition: Penicillins, Cephalosporins, Carbapenems, Vancomycin. Protein Synthesis Inhibition: Aminoglycosides (30S), Macrolides, Clindamycin, Tetracyclines (50S). Cell Membrane Disruption: Daptomycin, Polymyxins. Nucleic Acid […]
Introduction to bacteria: Virulence and pathogenicity (High-yield)
Infection process overview Steps in Infection: Attach → Persist → Invade → Adapt → Replicate → Exit/Spread Virulence: Ability to cause disease; not all colonizing bacteria cause infection. Host Factors: Skin integrity, immune status, social determinants, environment. Attachment and persistence Adhesins (bacterial) bind receptors (host). Pili often enhance adhesion. Site-specific colonization: e.g., Strep pyogenes → pharyngitis. Biofilms: Aggregates of bacteria […]
Introduction to bacteria: Classification and structure (High-yield)
Bacterial classification (Phenotypic) Gram Stain: Differentiates based on cell wall structure. Morphology: Cocci, bacilli, curved rods, clusters, chains. Growth Requirements: Oxygen tolerance (aerobes vs anaerobes). Biochemical Reactions: Catalase, coagulase, oxidase, lactose fermentation. Serologic Systems: Group A vs B Strep (based on surface antigens). Gram stain mechanism Crystal Violet → binds peptidoglycan. Iodine → forms […]
Clinical summary of genital ulcers
Syndrome Pathogen Appearance of Ulcer Pain Adenopathy Diagnosis Treatment Genital herpes HSV-2 more common than HSV-1 Multiple, small vesicles and ulcers with an erythematous base Painful Tender lymphadenopathy Scraping for HSV DNA by PCR or for cell cultureTzanck prep (Giemsa or PAP smear) less sensitive but quick Acyclovir, famciclovir, valacyclovir Syphilis Treponema pallidum Single (usually) […]