Microbiology Course - Bacteria, Antibiotics, and Diseases

Study Staphylococcus aureus, a gram-positive, beta-hemolytic, catalase- and coagulase-positive bacterium with protein A and hemolysin, causing skin infections, pneumonia, endocarditis, toxic shock, and food poisoning.

Streptococcus forms chains and drives disease through toxins, immune mimicry via m-protein, and pus formation, causing scarlet fever, necrotizing fasciitis, rheumatic fever, glomerulonephritis, pharyngitis, cellulitis, and impetigo.

Explore Bacillus anthracis, its toxin release and spore cycle, and the two forms: cutaneous with a painless black eschar and pulmonary with high mortality, highlighting ciprofloxacin treatment.

Detail borrelia transmission by deer ticks in northeast US, describe erythema migrans and three Lyme stages with carditis, Bell's palsy, arthritis, and encephalopathy, and cover doxycycline and amoxicillin for pregnancy.

Explore four E. coli types—haemorrhagic E. coli 0157 causing hemolytic uremic syndrome, enteropathogenic pediatric diarrhea, enterotoxigenic traveler's diarrhea, and enteroinvasive dysentery—plus penicillins and cephalosporins.

Campylobacter jejuni transmits via camping, animal contact, and fecal-oral routes; uses polar flagella and corkscrew motility; causes bloody diarrhea and can precede reactive arthritis or Guillain-Barre syndrome, treated with ciprofloxacin.

Legionella is an intracellular bacterium with no person-to-person spread; diagnosed by silver stain, charcoal agar, urine antigen; transmitted via water or air; hyponatremia is hallmark; treat with ciprofloxacin or macrolides.

Listeria causes foodborne illness from raw meat and unpasteurized dairy, transplacentally transmitted, and spreads intracellularly via listeriolysin O and an actin tail; dangerous for pregnant women and immunocompromised patients; ampicillin.

Identify Nocardia as a gram-positive, aerobic bacterium that forms filamentous branches in soil, mimicking tb with nodules and negative ppd, potentially spreading to the cns; treat with sulfonamides or trimethoprim.

Vibrio vulnificus is a free-living marine bacterium causing seafood- and wound-related infections, from mild illness to rapid, life-threatening necrotizing fasciitis; in hemochromatosis, treat with high-dose ceftriaxone or doxycycline immediately.

Explore measles caused by rubeola from the paramyxovirus family, spreading via coughing and sneezing, with fever, cough, coryza, conjunctivitis, Koplik spots, maculopapular rash, and encephalitis.

Neonatal conjunctivitis is diagnosed by onset timing with specific pathogens: Neisseria, Chlamydia, or viral infections; current prophylaxis uses two eye drops at birth from azithromycin, tetracycline, or silver nitrate.

Differentiate neonatal skin lesions such as nevus simplex, hemangioma, port wine stain, congenital melanocytic nevus, congenital melanocytosis, and caveolae, noting regression and associations with neurofibromatosis.

Rheumatic fever is an autoimmune reaction to Group A streptococci via renal tissue mimicry, diagnosed by Jones criteria, and treated with penicillin for five years, ten years if cardiac symptoms.

Scarlet fever, caused by group A streptococcus, features a sandpaper rash and strawberry tongue, with pharyngitis and fever; rapid strep confirms diagnosis, and penicillin prevents rheumatic fever.

Learn tuberculosis diagnosis using chest x ray, sputum analysis, acid-fast staining, and biopsy as the most accurate confirmation, plus the PPD skin test, IGRA blood assay, and induration thresholds.

Respiratory syncytial virus, enveloped single-stranded RNA virus of the paramyxovirus family, causes upper and lower respiratory illness in children, sometimes apnea in newborns; palivizumab targets F protein in high-risk infants.

Present a mnemonic for Pseudomonas aeruginosa highlighting pneumonia in cystic fibrosis, sepsis, ecthyma gangrenosum, UTIs, osteomyelitis, otitis externa, hot tub folliculitis, blue-green pigmentation, and antipseudomonal beta-lactams, aminoglycosides, and carbapenems.

Mycoplasma pneumoniae lacks a cell wall and is not gram stainable, but can be cultured on agar and causes walking pneumonia with mild symptoms despite x-ray findings, treated with macrolides.

Explore Bordetella pertussis, a gram-negative bacterium producing pertussis toxin, with three stages—catarrhal, paroxysmal (whooping cough and vomiting), and convalescent—preventable by vaccine and treated with macrolides like azithromycin.

Compare respiratory infections by hallmark signs: pertussis with whooping cough and butterfly chest; parainfluenza with barking cough and stridor; Haemophilus influenzae with drooling, treated with azithromycin or ceftriaxone as indicated.

Explains meningitis etiologies by patient group and early therapy, including Streptococcus pneumoniae, MRSA risks, newborn group B streptococcus, cryptococcal meningitis, and rash-based Lyme or Rocky Mountain spotted fever treatment.

Prp proteins misfold from alpha helical PrP C to beta sheet PrP Sc, causing non-inflammatory spongiform brain degeneration with axonal vacuoles, long incubation, and rapid onset.

Rabies spreads by bites from bats, raccoons, and skunks, and can be transmitted by breathing air; the virus travels via nerves to the brain, binding acetylcholine receptors.

Clostridium botulinum releases an exotoxin that blocks acetylcholine receptors, causing descending flaccid paralysis and botulism, with adults mostly from undercooked food and infants from honey spores.

Tetanospasmin exotoxin from clostridium tetani travels to the spinal cord, blocking GABA and glycine to cause spastic paralysis with sardonicus, trismus, and opisthotonus.

Clostridium difficile produces two toxins causing severe diarrhea and pseudomembranous colitis, after antibiotics like clindamycin, with diagnosis detecting the toxins and treatment using metronidazole, vancomycin, fidaxomicin, or fecal microbiota transplant.

Dengue fever, caused by the dengue virus and transmitted by Aedes mosquitoes, shares symptoms with chikungunya and is preventable through vaccines and environmental control; treatment relies on paracetamol and hydration.

Symptoms of dengue fever emerge 4–6 days after a bite with high fever, rash, headaches, joint pain, fatigue, and bleeding from low platelets. Treat with paracetamol and fluids; avoid aspirin.

Dengue virus, a flavivirus, transmits via the Aedes mosquito and co-infection with chikungunya is common; a recombinant dengue vaccine uses dengue genetics in a yellow fever shell to induce immunity.

Identify tinea corporis, or ringworm, as a fungal skin infection transmitted by skin-to-skin contact, presenting as a slowly expanding ring, diagnosed with coach and treated with topical azoles or terbinafine.

Differentiate staff syndrome, Stevens-Johnson syndrome, and toxic epidermal necrolysis by newborns 3 to 7 days old, mucosal involvement, sterile bullae, and full-thickness skin separation.

explain group b streptococcus in pregnancy and penicillin prophylaxis guided by a rectal vaginal culture at 37 weeks, plus fever during delivery and prolonged rupture of membranes.

Explore torches infections, detailing Toxoplasma, rubella, CMV, HIV, HSV-2, and syphilis, with maternal symptoms and newborn outcomes like blueberry muffin rash, cataracts, and hydrocephalus.

Explore hepatitis viruses A to E, their fecal-oral and bloodborne transmission, incubation differences, prognosis, cancer risk by type, and histology features like Councilman bodies and ground glass appearance.

Demonstrate Hepatitis B infection curve as viral replication with rising surface antigen and HBc, then anti-core antibodies reduce virus levels, creating window period and leading to immunity or chronic infection.

Explore hepatitis B serology by analyzing core genes and surface proteins to identify serology markers, including surface antigen and anti-HBs, signaling infection, immunity, and differentiating natural infection from vaccine immunity.

Explore hepatitis B therapy, including interferon as a last-resort treatment due to severe side effects like arthralgia, depression, and pancytopenia, and antivirals such as lamivudine, adefovir, telbivudine, tenofovir, and entecavir.

Treat acute hepatitis C; do not treat chronic infection, as prognosis depends on genotype. After therapy, vaccinate against other hepatitis viruses and monitor HCV RNA at 3 and 6 months.