🤧Infection and Immunology

Staphylococcus aureus (S. aureus)

Which gram positive cocci is transmitted by contact, respiratory, and ingestion located in the body as normal flora?

Staphylococcus aureus (S. aureus)

Which gram positive cocci has the common disease states:

• Impetigo

• Folliculitis

• Carbuncle

• Cellulitis

• Erysipelas

• Skin Abscess

• Staphylococcal Toxic Shock Syndrome (TSS)

• Staphylococcal Scalded Skin Syndrome (SSSS)

• Food poisoning (fruit salads, poultry and egg

  products, pastries)

• Endocarditis, sepsis/septic arthritis (milky joint fluid, especially those who use IV drugs)

• Hospital-acquired pneumonia

• Septicemia, surgical wound infections

Staphylococcal Toxic Shock Syndrome (TSS)

Which S. aureus disease involves fever, rash, hypotension and multiorgan system involvement associated with vaginal and nasal tampons and recent surgery?

Staphylococcal Scalded Skin Syndrome (SSSS)

Which S. aureus disease involves severe peeling skin with Nikolsky sign, and fever, irritability, poor oral intake in young children <6yo?

IV drug users

Which population is common/concerning for Staphylococcus aureus (S. aureus) infection with endocarditis, sepsis, and osteomyelitis?

Staphylococcus epidermis (S. epi)

Which gram positive cocci located in the body as normal flora likes to grow on plastic and can colonize lines/tubes/catheter with biofilm, transmitted by direct and indirect contact with contaminated people or objects and is a common cause of opportunistic infections like septicemia?

Staphylococcus saprophyticus

Which gram positive cocci located in the body as normal GI and vaginal flora is transmitted by direct contact and common cause of uncomplicated UTIs (esp. young sexually active AFABs)?

-Less commonly: acute pyelonephritis, urethritis, epididymitis, prostatitis

Streptococci pyogenes (S. pyogenes)

Which gram positive cocci is Lancefield Group A with normal flora on skin and pharynx transmitted by airborne droplets and hand contact with nasal discharge/contaminated objects?

Streptococci pyogenes (S. pyogenes)

Which gram positive cocci has the common disease states:

• Tonsillopharyngitis

  Complications:

• Scarlet Fever

• Acute Rheumatic Fever (ARF)

• Rheumatic Heart Disease

• Acute Glomerulonephritis (Post-streptococcal glomerulonephritis)

• Skin and Soft Tissue Infections

  • cellulitis, abscess, toxic shock syndrome

  • necrotizing fasciitis

Scarlet fever

Which S. pyogenes disease involves ‘sandpaper skin’ with erythema that blanches to pressure and strawberry tongue and increases risk for acute rheumatic fever (ARF)?

acute rheumatic fever (ARF)

Which S. pyogenes disease involves fever, arthritis, carditis and CNS involvement, usually 2-3 weeks after pharyngitis?

rheumatic heart disease

Which S. pyogenes disease occurs as a complication of acute rheumatic fever 10-20 years after original illness with mitral regurgitation leading to mitral stenosis?

acute glomerulonephritis

Which S. pyogenes disease occurs as an immune response attacking kidneys in children 5-12 yo with edema, hypertension, tea/rust colored urine (hematuria) and can lead to renal failure?

necrotizing faciitis

Which S. pyogenes infection involves the deep soft tissues and destruction of muscle fascia and overlying subcutaneous fat?

Streptococci agalactiae (S. agalactiae)

Which Group B gram positive cocci is Lancefield Group B with normal flora on skin and vaginal is transmitted by pregnancy and delivery, most concerning to neonates for infection with bacterial sepsis and meningitis?

Enterococcus faecalis and faecium

Which Lancefield Group D gram positive cocci with normal flora in gut, distal GU tract and skin is transmitted by direct or indirect contact with contaminated objects, materials, foods, hands of medical professionals causing UTI, endocarditis, peritonitis, bacteremia, nosocomial infections?

Streptococci pneumoniae (S. pneumo)

Which gram positive diplococci located in the body as normal flora in the nasopharynx is transmitted by droplets and has routine childhood vaccination and adult booster >65yo and causes otitis media, sinusitis, pneumonia, sepsis, meningitis?

Viridans group Streptococci

Which gram positive cocci group located in oropharynx as normal flora is transmitted by breaches in mucosa includes S. mutans and is a common cause of endocarditis?

intestinal tract

Streptotoccus gallolyticus is normal flora in the _____ of animals and human.

Streptococcus gallolyticus

Which gram positive diplococci is normal flora of the intestinal tract transmitted by direct/in animals and humans is an uncommon cause of endocarditis and bacteremia, and associated with colon cancer?

Bacillus anthracis (B. anthracis)

Which gram positive bacilli (rods/spores) causes disseminated disease through:

GI infection: spores in grasses → undercooked meat → hemorrhagic mesenteric adenitis
Skin infection: spores under the skin → eschar (marked edema and tissue necrosis)
Respiratory infection (inhalation): spores reach terminal bronchioles and alveoli → spread to mediastinal lymph → hemorrhagic mediastinitis

Bacillus cereus (B. cereus)

Which gram positive bacilli is found in soil and transmitted through consumption of contaminated food - reheated fried rice is classic presentation

Clostridium tetani (C. tetani)

Which gram positive bacilli (spores) is found in soil and transmitted through break in skin (deep inoculation and causes tetanus (uninhibited muscle contractions + lockjaw)?

Clostridium tetani (C. tetani)

Which gram positive bacilli (spores) causes tetanus and has routine childhood vaccination and adult boosters ~10 years?

Clostridium botulinum (C. botulinum)

Which gram positive bacilli is ubiquitous on surface of vegetables, fruits, seafoods, soil and marine and transmitted through ingestion of spores?

Clostridium botulinum (C. botulinum)

Ingesting the spores of which gram positive bacilli causes flaccid descending paralysis including:

• infant botulism with raw honey (possible contamination)

• pre-formed toxin in improperly canned foods

• introduction of bacteria to deep wound

Clostridium perfringens (C. perfringens)

Which gram positive bacilli is common in soil and normal flora of the large bowel and causes food poisoning and wound infections?

Clostridium perfringens (C. perfringens)

Which gram positive bacilli causes:
food poisoning: beef, poultry, legumes, gravies
wound infections of bowel (bullet wound) or through skin (higher risk in poorly vascularized tissue/delay in wound care)?

gas gangrene

What condition is caused by C. perfringens alpha toxin passing along the muscles and causing necrosis?

Clostridioides difficile (C. diff)

Which gram positive bacilli (spores/rods) is part of normal intestinal flora but can be suppressed by broad-spectrum antibiotics?

pseudomembranous colitis

What condition occurs when normal intestinal flora is suppressed by broad-spectrum antibiotics, causing C. diff spores to produce bacteria that secrete toxins (A,B)?

hospital patient

Which population is common/concerning for C. diff infection through person-to person transmission?

skin

Where is Corynebacterium sp located in the body as part of normal flora?

Corynebacterium diphtheriae (C. diphtheriae)

Which gram positive bacilli causes diphtheria and a grey and white pseudomembrane that adheres tightly to the throat and oropharynx?

Corynebacterium diphtheriae (C. diphtheriae)

Which gram positive bacilli causes diphtheria and involves routine childhood vaccination and boosters during pregnancy and adults working around infants?

Corynebacterium diphtheriae (C. diphtheriae)

Which gram positive bacilli is transmitted by direct contact with infected secretions or airborne?

Listeria monocytogenes

Which gram positive bacilli causes listeriosis that presents in:

• immunocompetent patients: self-limited acute febrile gastroenteritis

• immunocompromised patients: invasive infection like sepsis and meningitis

• vertical transmission: can cause pregnancy loss, preterm labor → sepsis and meningitis in neonates

Listeria monocytogenes

Which gram positive bacilli is transmitted through ingestion of contaminated foods or through vertical transmission (mother to fetus)?

• classically unpasteurized soft cheeses, unheated deli meats (cold cuts), premade deli salads, pates

neonates/fetuses and immunosuppressed

Which population is common/concerning for Listeria monocytogenes infection with sepsis and meningitis?

Gardnerella vaginalis

Which gram positive bacilli is part of vaginal normal flora but can cause bacterial vaginosis (BV) due to changes in vaginal flora and subsequent overgrowth of bacteria?

Malassezia furfur

Which fungus is normal flora of the skin, is not contagious (benign) and cause of non-pruritic pityriasis versicolor (tinea versicolor)?

Dermatophytes

Which fungi are transmitted by infected skin scales (human-to-human), animals (pets) and contaminated surfaces and causes itching, scaling skin patches that become inflamed and weep?

• over 20 species of tineas

Sporothrix schenckii

Which fungus is transmitted by traumatic lacerations/puncture wounds from contaminated soil/decaying vegetation and causes sporotrichosis and erythema nodosum?

• rose gardener’s disease: occupational hazard

• infects epidermis, can spread along lymphatic system to subcutaneous tissue and bone or CNS

• no person-to-person transmission

Coccidioides immitis

Which fungus is transmitted by inhalation of mold in soil in Southwestern US, Central and South America and causes coccidiomycosis (Valley Fever) with flu-like symptoms?

• causes 15-30% of community-acquired pneumonia

people working in soils/construction

Which populations are common/concerning for Coccidioides immitis infection with coccidiomycosis (Valley Fever) in Southwestern US, Central and South America?

Histoplasma capsulatum

Which fungus is transmitted by inhalation of soil contaminated with bird/bat droppings prevalent in Ohio and Mississippi River Valleys and causes histoplasmosis with flu-like symptoms?

people renovating old houses/barns

Which populations are common/concerning for Histoplasma capsulatum infection with histoplasmosis in Ohio and Mississippi River Valleys?

Blastomyces dermatitidis

Which fungus is transmitted by inhalation of decaying wood and soil and causes blastomycosis in South Central and Southeastern US?

• flu-like symptoms, possible dissemination to skin, bones, joints

people working in excavation/construction

Which populations are common/concerning for Blastomyces dermatitidis infection with blastomycosis in South Central and Southeastern US?

Candida albicans

Which fungus flourishes when competing bacterial flora are eliminated and causes candidiasis?

• cutaneous infections

• oral thrush

• vulvovaginal vaginitis or vulvitis

• diaper rash in infants

Immunocompromised: causes invasive systemic infections (esophageal, systemic into GI tract, kidneys, liver, spleen, blood)

Candida albicans

Which fungus is normal flora of the skin, mouth, vagina, and intestines?

immunocompromised patients with low CD4 counts

Which population is common and concerning for Candida albicans infection with candidiasis?

Cryptococcus neoformans

Which fungus is transmitted by inhalation of soil rich in bird droppings (esp. pigeons) and causes:

• causes mild lung infection in healthy patients

• immunocompromised: cryptococcal meningitis (disseminates to brain and meninges)

Aspergillus

Which fungus is transmitted by inhalation of dust soil and mold spores in the air and causes aspergillosis?

• construction workers at higher risk

• produces mycotoxins → liver damage/liver cancer

• can disseminate from lung to GI, brain, other organs

• symptoms range from allergic reaction to bloody cough and fatigue

Pneumocystis jiroveci

Which fungus is transmitted airborne person-to-person and causes Pneumocystis pneumonia (PCP)?

• almost 100% fatal if untreated

• common disease in AIDS patients/immunocompromised

Pneumocystis pneumonia (PCP)

Which fungal infection presents like a virus on chest x-ray and is successfully treated with an antibiotic (TMP/SMX- Bactrim)?

• almost 100% fatal if untreated

• common disease in AIDS patients/immunocompromised

Entamoeba histolytica

Which intestinal protozoa is transmitted via ingestion of food or water containing contaminated cysts and causes:

• amebiasis (diarrhea)

• amebic dysentery (bloody diarrhea and fever)

  • common in tropical areas with poor sanitary conditions

  • rarely can disseminate to liver (forms abscess), lungs/brain

Giardia lamblia

Which intestinal protozoa is transmitted by waterborne, food-borne, fecal-oral routes and causes giardiasis (foul smelling, fatty, watery diarrhea)?

• most commonly diagnosed parasitic intestinal disease in US (hikers)

• ingestion of raw/undercooked food contaminated with cysts or via food contaminated after cooking

• person-to-person transmission in childcare settings

Cryptosporidium species

Which intestinal protozoa is transmitted fecal-oral by ingestion of contaminated recreational water, drinking water, or food, or contact with infected persons or animals and causes Cryptosporidiosis?

• Cryptosporidiosis: profuse, watery diarrhea that can last up to 3 weeks in immunocompetent patients

  • immunocompromised: can lead to life-threatening malnutrition and wasting

cryptosporidiosis

The intestinal protozoa Cryptosporidium species causes which infection involving:

• profuse, watery diarrhea that can last up to 3 weeks (immunocompetent)

• life-threatening malnutrition and wasting (immunocompromised)

Trichomonas vaginalis

Which urogenital protozoa is transmitted by sexual contact and causes trichomoniasis?

• the most common protozoal urogenital tract infection of humans

trichomoniasis

Which infection involves these symptoms?

AFAB (more commonly symptomatic)

• Inflammation of mucosal tissue of vagina, vulva, cervix

• Copious, yellowish/greenish or white frothy, malodorous vaginal discharge

AMAB (less commonly symptomatic)

• Infects urethra, prostate and seminal vesicles

• Commonly asymptomatic

• Whitish penile discharge

Plasmodium falciparum

Which urogenital protozoa is transmitted by infected mosquito bite or contaminated needle and causes malaria?

• fever, chills, shaking, vomiting, joint aches, fatigue, diarrhea

Babesia sp.

Which urogenital protozoa is transmitted by infected tick bites and causes Babesiosis?

• flu-like symptoms

• can cause to hemolytic anemia (multiplies in red blood cells and ultimately lysing cells) and severe disease

Toxoplasma gondii

Which urogenital protozoa is transmitted by ingestion of infected cat feces, raw or undercooked meat, and vertical transmission and causes toxoplasmosis?

• from asymptomatic or mild flu-like symptoms to severe encephalitis (pregnancy)

• leading cause of death from food-borne illness in US

Cestodes

Which helminths are tapeworms transmitted via ingestion of undercooked meat containing larvae or eggs (pork, beef) and fecal-oral route causing many symptoms including cysticercus/cysticercosis?

Trematodes

Which helminths are flukes transmitted via snails in contaminated freshwater by absorbing into human skin and causing Schistosomal infection?

• rash, fever, chills, cough

• can invade bladder and liver

Nematodes

Which group of helminths are Pinworms (roundworms) that cause enterobiasis (perianal itching) transmitted by:

• ingestion (contaminated foods/drinks, touching fomites)

• inhaled if eggs become airborne

• direct penetration of skin

Cimex species

Which parasites are transmitted by contact with infested surface (not transmitted person-to-person) and bites cause itching and loss of sleep?

• bed bugs

Sarcoptes scabiei

Which parasites are transmitted by direct contact with fomites and cause scabies?

• intensely pruritic papular rash with possible burrows

  • usually not on head

• crowded conditions increase risk

Pediculus humanus capitis

Which parasites are transmitted by head to head contact or via fomites (debatable) causing pediculosis capitis?

• scalp pruritus occurs as an allergic reaction to head lice saliva injected during feeding

• lice do not jump, fly, or use pets as vectors

Pediculus humanus humanus

Which parasites are transmitted by direct contact and via fomites causing pediculosis coporis?

• widespread body pruritus as an allergic reaction to body lice saliva injected during feeding

• primarily resides in clothing rather than on skin or hair

  • often involving the trunk areas

prions

What is the causative agent of TSE (transmissible spongiform encephalopathies, including dementia and behavioral changes?

• Unconventional infectious agents

• Can cause brain tissue destruction

prions

What do these characteristics describe?

• Do not trigger an immune or inflammatory response

• Some can be inherited and cause disease, unlike conventional infectious diseases

• Extremely resistant to UV light, x-rays, chemical agents that typically inactivate viruses and bacteria

• Invariably fatal

Herpes simplex viruses types 1 & 2 (HSV)

Which DNA Herpesviruses is transmitted by direct inoculation of mucocutaneous surfaces and causes oral/genital herpes, herpetic whitlow, encephalitis?

herpetic whitlow

What condition is caused by herpes simplex viruses types 1 & 2 (HSV) and involves herpes infection on the hands/fingers, and is a possible occupational hazard (dentistry)?

Varicella-zoster virus (VZV)

Which DNA Herpesviruses is transmitted by respiratory droplet and direct contact with lesions and causes varicella (chickenpox) → recurrent infection causes zoster (shingles)?

• Vaccination available

Cytomegalovirus (CMV)

Which DNA Herpesviruses is transmitted by vertical (placenta), saliva, sexual, blood transfusion and causes asymptomatic infection (most common) but also congenital disease and CMV mononucleosis-like syndrome?

• 80% of population have antibodies

• immunocompromised at higher risk

Epstein-Barr virus (EBV)

Which DNA Herpesviruses is transmitted by saliva exchange and causes mononucleosis?

mononucleosis

What condition is caused by Epstein-Barr virus (EBV) usually in younger individuals and involves:

• pharyngitis (posterior cervical chain lymph nodes)

• fever

• lymphadenopathy

• splenomegaly (athletes need to avoid contact sports due to splenic rupture)

Human herpesvirus 6

Which DNA Herpesviruses is transmitted by saliva exchange and causes roseola?

roseola

What condition is caused by Human herpesvirus 6 usually in young children and involves high fever (fever of unknown origin w/o other symptoms) followed by classic rash?

• also called 6th disease

Molluscum contagiosum virus (MCV)

Which DNA Poxvirus is transmitted by close personal contact and causes molluscum contagiosum?

molluscum contagiosum

What condition is caused by Molluscum contagiosum virus (MCV) usually in young children, with flesh colored umbilicated lesions that appear all at once, starting on face and palms?

Mpox virus

Which DNA Poxvirus is transmitted by person-to-person, vertical, sexual contact and causes rash, fever, headache and fatigue?

• Vaccination available

Mpox rash

Which Poxvirus rash involves vesicles or pustules that are deep-seated, firm or hard, well-circumscribed, lesions may umbilicate or become confluent and progress over time to scabs?

Human papilloma virus (HPV)

Which DNA virus is transmitted by sexual contact and skin-to-skin and causes genital warts and can cause cancer (cervical, anal, oropharyngeal, vulvar, penile)?

• Vaccination available

Parvovirus B19

Which DNA virus is transmitted by respiratory route and causes Erythema infectiosum?

Erythema infectiosum

Which Parvovirus B19 condition involves “slapped cheek” erythema usually in children several days after a fever, runny nose, and headache?

• also fifth disease, Slapped Cheek Disease

Hepatitis B virus

Which DNA virus is transmitted by blood, sexual, vertical contact and causes acute hepatitis?

• Vaccination available

• additionally fulminant hepatitis and chronic hepatitis are possible

  • also co-infection with possible Hepatitis C or D possible

• the most common blood-borne infection worldwide

Complications

• hepatocellular carcinoma

• cirrhosis (liver scarring)

acute hepatitis

Which Hepatitis B and D condition involves jaundice (icterus) fever, malaise?

fulminant hepatitis

Which Hepatitis B and D condition involves rapid (days to weeks) and massive necrosis of liver parenchyma and decrease in liver size?

Adenoviruses

Which DNA viruses are transmitted by aerosol droplet and fecal-oral and causes the common cold (upper respiratory infection) and diarrhea (enteric form) especially in children?

upper respiratory infection (URI)

What condition involves coughing, sneezing, rhinitis, conjunctivitis, sore throat?

• caused by adenoviruses, parainfluenza viruses, RSV, coronavirus, rhinovirus

Coxsackie viruses A & B

Which RNA viruses are transmitted by fecal-oral and cause:

• A virus: hand, food, mouth disease (HFMD) and herpangina (mouth blisters)

• B virus: pleurodynia, myocarditis/pericarditis

Poliovirus

Which RNA virus is transmitted fecal-oral and causes paralytic poliomyelitis (paralysis of muscles when RNA virus enters the CNS)?

• Vaccination available

Hepatitis A virus (and Hep E)

Which RNA viruses are transmitted fecal-oral and cause fever, jaundice, and hepatomegaly?

• Vaccination available for Hepatitis A

Hepatitis D virus

Which RNA virus is transmitted by blood, sexual and vertical contact (only by people with hepatitis B infection) and causes a more severe form of acute hepatitis?

• Hepatitis B vaccination provides protection against both

Hepatitis C virus

Which RNA virus is transmitted by blood, vertical and sexual (less common) contact and causes acute and chronic hepatitis, can be asymptomatic?

IV drug users, incarcerated populations

What populations are common/concerning for Hepatitis C virus infection?