Infections based on predominant disease location (tropism)
Healthy Organisms associated with a healthy microbiome Bacteroides (GI tract) Lactobacillus (Vagina) Staphylococcus epidermidis (Skin) Head Central Nervous System (CNS) Meningitis: Differentiate by age (newborn, adult, elderly) and by “septic” (culture +) vs “aseptic” (culture negative – usually virus, prior antibiotics, or drug-induced). Bacteria: Neonate: E. coli, Group B Strep, Listeria Infant: Neisseria meningitidis, Strep […]
Outline of parasitic diseases and organisms according to site/specimen
Blood Plasmodium, Babesia, Trypanosoma, Microfilaria (Leishmania and Toxoplasma can be blood-bourne, but are not usually seen on the peripheral blood smear.). CSF Trypanosoma brucei, Naegleria, Angiostrongylus (eosinophilic meningitis). Brain Neurocysticercosis (Tinea solium), Toxoplasma. Eye Acanthamoeba, Toxoplasmosis, Onchocerciasis, Loa loa, visceral larva migrans (Toxocariasis). Mouth/Throat Ascaris. Sputum/Lung Ascaris, Strongyloides, Pneumocystis, Paragonimus. Abdomen/Ascites Echinococcal cysts, Entamoeba histolytica […]
Pharmacology: Introduction to antimicrobial therapy
High-yield summary 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. […]
Principles of laboratory diagnosis
High-yield summary 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) […]
Current Events
All Mental Health Vector Borne Disease Heat Impact Extreme Weather Water/Food Borne Illness Degraded Air Quality The Impact of Hurricane Katrina on the Mental and Physical Health of Low-Income Parents in New Orleans 9/11/2025 “Long-term health and mental health services are needed for low-income disaster survivors, especially those who experience disaster-related stressors and loss.” The […]
Ectoparasites
Scabies/Sarcoptes Human-to-human spread. Clinical: intensely itchy papular rash (hands, wrists, elbows, webbing between fingers, penis, scrotum), or occasionally diffuse non-pruritic rash in immune suppressed patients (crusted scabies). Secondary bacterial infection is common. Dx: Skin scraping or adhesive tape (look for mites, eggs or feces). Rx: Lindane, etc. Lice/Pediculosis Three types: Head louse Body louse Pubic […]
Trematodes
check yourself Fill in these summary tables to check your learning. Flukes Non-segmented flat worms. Schistosomiasis (Blood fluke) A very common parasitic disease with significant morbidity and mortality. Human reservoir (or animal reservoir for some species) with snails in life cycle. Infection occurs when humans are in water and schistosomal cercariae (from snails) penetrate human […]
Cestodes
check yourself Fill in these summary tables to check your learning. Tapeworms Segmented flat worms. Taenia sagniata (Beef tapeworm) Humans ingest undercooked beef containing cysticerci, larvae attach to bowel wall and mature to adult worms that eventually shed proglottids into feces that are eaten by cattle. Humans are the definitive host, and cows the intermediate […]
Nematodes
check yourself Fill in these summary tables to check your learning. Round worms GI Enterobius (Pin worm) Transmitted by ingestion of eggs, which develop into adults within the gut. Females migrate to rectum/anus to lay eggs on skin. Symptoms are associated with this migration and lead to intense anal pruritis (itchy butt). Re-infection is common […]
Protozoa
check yourself Fill in these summary tables to check your learning. Amoeba About the size of WBCs, but move by pseudopodia. Entamoeba histolytica (amebiasis) Obligate human parasite that are transmitted to humans by ingestion of the cysts shed in asymptomatic carriers’ stool. Cysts form trophozoites in intestine where they can eat RBCs and invade the […]