Respiratory, Digestive Systems, and Gentourinary

s covering key concepts in the respiratory and digestive systems, focusing on pathogens, their characteristics, and diseases.

Streptococcus pyogenes

Beta-hemolytic Gram + cocci in chains, bacitracin-sensitive streptococcus causing strep throat.

Symptoms of strep throat

Whitish tonsillar exudate, inflamed pharynx, fever.

Complications of Strep pyogenes

Scarlet fever, septicemia, rheumatic fever, glomerulonephritis.

Common causes of colds

Rhinoviruses, with over 100 serotypes.

Cold transmission

Hand-to-hand contact, fomites, and limited droplet spread.

Catalase test for Streptococcus

Catalase-negative reaction.

Pneumococcal pneumonia cause

Streptococcus pneumoniae; encapsulated, lancet-shaped diplococci, optochin sensitive.

Mycoplasma pneumoniae

No cell wall; causes primary atypical pneumonia.

Legionellosis cause

Legionella pneumophila; grows in water systems; intracellular pathogen.

Pertussis cause and traits

Bordetella pertussis; gram-negative coccobacillus; produces pertussis toxin.

Mycobacterium tuberculosis characteristics

Acid-fast, slow-growing rod; forms tubercles; leading infectious killer.

Cause of croup

Parainfluenza virus; causes barking cough in children.

Characteristics of hantavirus

Sin Nombre virus; linked to inhaled rodent droppings; respiratory distress.

Histoplasmosis cause

Histoplasma capsulatum; dimorphic fungus found in bat/bird-dropping soil.

Coccidioidomycosis cause

Coccidioides immitis; Valley Fever associated with spores in desert soils.

Pneumocystis carinii classification

Classified as a fungus; major pneumonia in AIDS patients.

Cause of dental caries

Streptococcus mutans produces glucan and lactic acid damaging enamel.

Periodontal disease cause

Porphyromonas gingivalis leading to gingivitis and periodontitis.

Cause of mumps

Mumps virus; spreads via respiratory/saliva; causes parotitis and orchitis.

Diseases caused by pathogenic E. coli

ETEC (traveler's diarrhea), EHEC (HUS), EPEC (infant diarrhea), EIEC, EAggEC.

Characteristics of Shigellosis

Low infectious dose; fecal-oral spread; Shiga/shiga-like toxin; bloody stools.

Cause of cholera

Vibrio cholerae; rice-water stools; severe dehydration requiring rapid fluid replacement.

Characteristics of Helicobacter pylori

Produces urease; survives stomach acid; causes gastritis and ulcers.

Characteristics of Entamoeba histolytica

Protozoan amoeba; causes amoebic dysentery and liver abscesses.

Characteristics of Norwalk virus

Fecal-oral spread; causes nausea, vomiting, diarrhea; associated with cruise ship outbreaks.

Characteristics of Ascaris lumbricoides

Roundworm; migrates through lungs; can cause intestinal obstruction.

Most common cause of UTI

Escherichia coli.

Characteristics of Leptospira interrogans

Spirochete; enters through contaminated water; causes kidney/liver disease.

Characteristics of Neisseria gonorrhoeae

Pili adhesion causing PID, urethritis, and infertility.

Stages of syphilis

Primary chancre → secondary rash → latent → tertiary gummas; caused by Treponema pallidum.

Ureaplasma urealyticum

Causes nongonococcal urethritis.

Cause of chancroid

Haemophilus ducreyi; causes painful soft genital ulcer.

Characteristics of HPV

DNA virus causing genital warts; linked to cervical cancer, not culturable.

Cause of toxic shock syndrome

TSST-producing Staphylococcus aureus associated with tampons.

Routes of hepatitis transmission

HAV - fecal-oral; HBV - blood/sex/perinatal; HCV - blood/sex; HDV requires HBV; HEV - fecal-oral.

Most common helminth in USA

Pinworm (Enterobius vermicularis).