Micro Case Study

Aspergillus flavus

FUNGI

• Farmers, inhalation/environment, non-dimorphic, fungal ball

• Inhalation

• Recoverable, but can be fatal

• not contagious

• Skin test if pneumonia, can infect wounds

Candida albicans 

FUNGI

• Yeast infections (oral thrush, vaginal, diaper rash, yellow fungal nail, from antibiotics/immune suppression/diabetes )

• Contact 

• Recoverable

• Biofilm, adhesins

Histoplasma capsulatum 

FUNGI

• Soil/cave with bat/bird droppings, looks like TB due to granulomas (evade by macrophage) 

• Recoverable

• yeast phase

• not contagious

• skin lesions

Cryptococcus neoformans 

FUNGI

• Bird droppings, meningitis (headache, stiff neck), capsule (inhalation) 

• Recoverable, sometimes not in HIV/immunocompromised

• not contagious

Haemophilus influenzae

GRAM-

• Droplets, meningitis/pneumonia, unvaccinated, gram-

• gram- coccobacillus (rod)

• Can be serious

• contagious

Helicobacter pylori

GRAM-

• Oral-oral/fecal-oral, gastritis, ulcers, urease-pos 

• gram- spirilum

• Can be serious

• Urease (acid-neutralizing), flagella, toxins 

• contagious

Listeria monocytogenes 

GRAM-

Foodborne, contaminated, pregnant 

Can be serious

Survives the cold 

not contagious, just food

Neisseria meningitidis 

GRAM-

• College/military, rash (inhalation, close contact)

• gram- coccus

• Can be serious and deadly 

• Pili, endotoxin, capsule

• contagious

Psuedomonas aeruginosa

GRAM-

• Hot tub, environment (water/soil), resistant to abx, infections

• Exposure

• Can be serious, also recoverable

• Exotoxin, biofilm (green toxin)

• generally not contagious, environment 

Shigella

GRAM-

• Bloody diarrhea, fever, low infectious dose, fecal-oral (contaminated food), shiga toxin, not normally in gut  

• Can be serious, mostly recoverable 

• Shiga toxin

• contagious (fecal-oral)

Neisseria gonorrhea 

GRAM- (diplococcus)

• STD, purulent discharge, painful urination, outside cells, non-menstrual bleeding, infection of tubes

• pus, inflammation

• contagious

Bacillus anthracis 

GRAM+

Spore forming, animal, soil, bioweapon 

Can be deadly

not contagious

Clostridium botulinum 

GRAM+

• Flaccid paralysis, neurotoxin blockes Ach (foodborne) 

• Can be deadly

• Botulinum toxin, spore

• not contagious

Clostridium tetani 

GRAM+

• Spastic paralysis, lockjaw, toxin blocks inhibitory nt, deep wound infection 

• Can be deadly

• Tetanus toxin, spores (enter wounds)

not contagious

Streptococcus mutans 

GRAM+

• Dental, biofilm on teeth, sugar (oral) 

• sucrose for adhesion, acid production

contagious, saliva

Streptococcus pneumoniae 

GRAM+

• Rust-colored sputum, gram+ diplococcus, capsule, respiratory  

• Polysaccharide capsule

• contagious

Streptococcus pyogenes 

GRAM+

• group A Strep throat, fasciitis, toxic shock, droplets/skin contact 

• scarlet fever

• contagious

Cryptosporidium parvum 

PROTIST

• Contaminated water (fecal/oral), low fever for weeks, waterpark, flagellum, trophozoite cyst 

• contagious

Entamoeba histolytica 

PROTIST

• Bloody diarrhea (dysentery), liver, tropical, fecal-oral 

• Cyst form

• contagious, fecal-oral

• chronic, top parasite-death cause

Toxoplasma gondii 

PROTIST

• Cats, undercooked meat, dangerous in pregnancy  

• Intracellular survival

• not contagious

Fifth disease 

VIRUS ssDNA

• Lacey rash, slapped cheek, respiratory, face to trunk/body

• Non-enveloped

Hepatitis 

VIRUS (B is dsDNA, rest are ssRNA)

• Jaundice, dark urine, fatigue, fecal-oral or sex 

Herpes simplex virus I or II 

VIRUS dsDNA

• Cold sores (1)/genital blisters (2), stress, latent periods in sensory ganglia, lesions contact 

HIV

VIRUS ssRNA

• Blood, attacks CD4, chronic progression 

Human papillomavirus (HPV)  

VIRUS dsDNA

• Genital Warts, cervical cancer 

• non-enveloped, stable 

Roseola 

VIRUS dsDNA

• High fever, bumpy rash after fever, lasts long

Rotavirus 

VIRUS ssRNA

• Severe diarrhea in infants, dehydration (vaccine) 

Ascaris lumbricoides 

WORM

• Intestinal, if advanced drugs don’t work, worms in stool, blocks digestion, lungs (ingestion)  

• Fecal/oral (contamination)

• thick eggshell, migration

Hookworm 

WORM

• Stuck in skin, visibly seen, can get into digestive, itchy rash, walking barefoot you get eggs (contact) 

• skin penetration, blood feeding (anemia)

Taenia (tapeworm) 

WORM

 -Undercooked beef, neurocysticitis, segments in stool (seizures) ingestion  

• Scolex (hooks, suckers), cyst formation, absorbs nutrients