Master List of All Bacterial Diseases

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Staphylococcal aureus Infections

• transmission: through follicles

• symptoms: pimples, styes, or furuncle → carbuncle

• virulence factors:

  • coagulase

  • leucocidin

  • peptidoglycan layer allows it to resist lysosomal digestion

• categories: exotoxin-producing

Impetigo

• pathogens: S. aureus and S. pyogenes

• transmission: superficial layer of the skin

• categories: multiple pathogens

Scalded Skin Syndrome

• pathogen: S. aureus

• transmission: enters bloodstream

• symptoms: skin redness, peeling of the skin, bullous impetigo

• virulence factors:

  • exfolitative toxins (ETA, ETB)

• categories: exotoxin-producing

Toxic Shock Syndrome (TSS)

• pathogen: S. aureus

• symptoms: high fever, sunburn-like rashes, shock, multi-organ failure

• virulence factor:

  • TSST-1 is a superantigen

  • causes cytokine storms → shock and multi-organ failure

Group A Streptococci (GAS)

• pathogen: Streptococcus pyogenes

• virulence factor:

  • erythrogenic toxin → “scarlet fever”

  • hemolysins, streptolysins, M protein, capsules, streptokinase, hyaluronidase, and deoxyribonucleases

• streptococcal superantigen toxins → streptococcal toxic shock syndrome (STSS)

• categories: exotoxin-producing

Acne

• pathogen: Cutibacterium acnes

• cause: excessive sebum/oil

• symptoms: inflammation of hair follicles

Pseudomonas dermatitis

• pathogen: Pseudomonas aeruginosa, an opportunistic gram-negative pathogen

• transmission: contaminated water

• symptoms: “hot-tub rash”

• virulence factors:

  • antibiotic resistances

  • exotoxins

  • endotoxins

  • grow in biofilm

• at-risk: compromised, severe wound or burn patients

• categories: exotoxin-producing

“Pink Eye”

• pathogens: S. aureus, S. pyogenes, N. gonorrhoeae, H. influenzae, and P. aeruginosa

• symptoms: redness, irritation, and purulent discharge

• treatment: antibiotic eye drops or ointments

• categories: multiple pathogens

Ophthalmia neonatorum

• pathogen: N. gonorrhoeae, C. trachomatis

  • obligate intracellular

• symptoms: inflammation of the eyes

• at-risk: newborns

• treatment: silver nitrate (prophylaxis), antibiotics

• categories: obligate intracellular, multiple pathogens, birth canal transmission

Trachoma

• pathogen: C. trachomatis

  • obligate intracellular

• symptoms: trichiasis (inward eyelashes), cornea scarring → potential blindness

• a chronic conjunctival infection caused by serovars of Chlamydia trachomatis

  • an obligate intracellular bacterium

• at-risk: areas of poor sanitation or limited healthcare access

• categories: obligate intracellular

Urinary Tract Infections (UTI)

• pathogens: E. coli (causes 80%), others: Proteus and Klebisella

• transmission: nosocomial (in hospitals) due to procedures like urinary catheterization

• symptoms: dysuria, urinary urgency, frequency, hematuria

• categories: multiple pathogens

Bacterial Vaginitis

• pathogen: G. vaginalis

  • anaerobe

• cause: disruption of normal vaginal microbiota → pH increase → overgrowth

• symptoms: thin, grayish-white vaginal discharge, fishy odor

• diagnosis: presence of “clue cells” which are vaginal epithelial cells coated with bacteria (requires microscope)

Gonorrhea

• pathogen: N. gonorrhoeae

• virulence factors:

  • attachment pili

  • endotoxins

  • Opa proteins

  • IgA protease

• reservoir: humans

• at-risk: women and newborns

• if untreated, may lead to pelvic inflammatory disease (PID)

Syphillis

• pathogen: Treponema pallidum

  • spirochete

• transmission: sex or direct contact → enters bloodstream

• symptoms:

  • primary: painless chancre (ulcers)

  • secondary: kin rashes and mucous patches in mouth

  • tertiary: gumma development as a inflammatory response

• transplacental → congenital syphillis → fetal death or severe neurological damage

• categories: transplacental

Nongonococcal Urethritis (NGU)

• pathogen: C. trachomatis

  • obligate intracellular

• transmission: sex or direct contact

• symptoms: inflammation of the urethra

  • may progress into pelvic inflammatory disease (PID) in women

• categories: obligate intracellular

Streptococcal Pharyngitis (“Strep Throat”)

• pathogen: S. pyogenes (GAS)

• transmission: person to person via droplets

• symptoms: sore throat, fever, and inflammation of the tonsils and pharynx

  • may develop into rheumatic fever or glomerulonephritis

Diphtheria

• pathogen: Corynebacterium diphtheriae

• transmission: person to person via droplets

• symptoms:

  • suffocation from pseudomembrane

    • bleeding if scraped off

• virulence factors:

  • Diphtheria toxin, an exotoxin on a prophage: inhibits protein synthesis

  • pseudomembrane formed on airways

• reservoir: humans

• vaccine: DTaP vaccine available from toxoid

• categories: exotoxin-producing, vaccine

Whooping Cough (Pertussis)

• pathogen: Bordetella pertussis

  • gram-negative

• symptoms:

  • catarrhal stage: common cold symptoms

  • paroxysmal stage: violent coughing & potential cyanosis complication from mucus build-up

  • convalescent stage: gradual recovery; may come back with secondary infection

• virulence factors:

  • tracheal cytotoxin, pertussis toxin

  • possess an endotoxin from LPS

• reservoir: humans

• vaccine: DTaP vaccine available

• categories: exotoxin-producing, vaccine

Pneumococcal Pneumonia

• pathogen: Streptococcus pneumoniae

• symptoms: inflammation and fluid accumulation in alveoli

• virulence factor:

  • polysacchraide capsule

    • others: Haemophilus influenzae and Staphylococcus aureus

• vaccine available for S. pneumoniae

• categories: vaccine

Mycoplasmal Pneumonia “Walking Pneumonia”

• pathogen: Mycoplasma pneumoniae

  • lacks a cell wall

• symptoms: milder than Pneumococcal Pneumonia

Legionnaires Disease

• pathogen: Legionella pneumophila

  • a gram-negative rod

• transmission: aerosolized water droplets

  • human to human transmission is extremely rare

• virulence factors:

  • survives and replicates in macrophages

Tuberculosis (TB)

• pathogen: Mycobacterium tuberculosis

  • thick peptidoglycan wall

• causes: enters bloodstream → affects lungs with necrotic tissue

• virulence factors:

  • grows slow and survives in macrophages and sputum

  • may remain dormant in body even after recovery

    • reactivates when person is immunocompromised

• at-risk: immunocompromised individuals

• diagnosis: skin test

• vaccine available, but effectiveness is questionable

  • drug-resistant strains are increasingly common

• categories: multiple-drug resistances

Staphylococcus aureus Food Intoxication

• pathogen: S. aureus

• causes: irritates intestinal lining

• symptoms: nausea, vomiting, abdominal cramps, diarrhea

• virulence factors:

  • heat stable entertoxins (rare)

Bacillus cereus Food Poisoning

• pathogens: B. cereus

  • spore-forming

• symptoms: vomiting (emetic) and abdominal cramps and diarrhea (diarrheal)

• virulence factors:

  • emetic toxin: performed

  • diarrheal toxin: produced after ingestion

• categories: exotoxin-producing, endospore-forming

Clostridium perfringens Food Poisoning

• pathogen: C. perfingens

  • endospore-forming

• transmission: soil and intestines of animals and humans

• virulence factors:

  • enterotoxin

    • damages intestinal cells and causes diarrhea

• can also cause "gas gangrene”

• categories: endospore-forming, exotoxin-forming

Salmonella Gastroenteritis (Non-Typhoidal Salmonellosis)

• pathogen: Salmonella enterica

• transmission: fecal-oral route from contaminted meat, eggs, dairy products

• symptoms: diarrhea, abdominal cramps, and fever

• virulence factor:

  • produces enterotoxin

• self-limiting → primarily localized to intestinal tract

• categories: exotoxin-producing

Typhoid Fever

• pathogen: Salmonella enterica serovar Typhi (S. Typhi)

• symptoms: systemic inflammation

• virulence factor:

  • LPS endotoxin

  • multiplies in macrophages

  • survives in gallbladder

• reservoir: only infects humans

• treatment: antibiotics

• vaccine: attenuated

• carcinogenic: gallbladder cancer

• categories: carcinogenic and vaccine

Shigellosis (Bacillary Dysentery)

• pathogen: Shigella species → S. sonnei and S. dysenteriae

  • gram-negative, z

• transmission: via fecal-oral route

• symptoms: bloody and mucoid diarrhea & dehydration and electrolyte imbalance

• reservoirs: humans and primates

• S. dysenteriae → Shiga exotoxin (neurotoxin)

  • could lead to Hemolytic Uremic Syndrome (HUS)

• categories: exotoxin-producing

Cholera

• pathogen: Vibrio cholerae

  • transmission: contaminates water and shellfish living in water

  • other: Vibrio parahaemolyticus → causes gastroenteritis

    • milder form of the disease called vibrosis from raw or undercooked seafood

• produces enterotoxin, cholera toxin

  • binds to intestinal epithelial

  • stimulates hyper-secretion of water → “rice-water stools”

• cholera vaccines are available

Enteroinvasive Escherichia coli strains (EIEC)

• pathogen: E. coli

  • opportunistic

• invades mucosal cells and gains access to submucosa of large intestine

• causes inflammation and dysentery

  • similiar to Shigella

Enterotoxigenic Escherichia coli strains (ETEC)

• pathogen: E. coli

  • opportunistic

• produce enterotoxins that are carried on plasmids (horizontal gene transfer)

• stimulates increased fluid secretion in small intestine

  • causes watery diarrhea and severe dehydration

• common cause of Traveler’s diarrhea

Enterohemorrhagic Escherichia coli strains (EHEC)

• pathogen: E. coli

• produces a Shiga-like toxin (aka. Shiga toxin-producing E. coli [STEC])

• most well-known serotype of E. coli

• causes bloody diarrhea

• may develop into Hemolytic Uremic Syndrome (HUS)

• reservoir: gastrointestinal tract of cattle

Campylobacter Gastroenteritis / Campylobacteriosis

• caused by Campylobacter jejuni

  • C. fetus is less common but is higher risk to cause systemic infections in high-risk patients

    • rare complication: Guillain-Barre syndrome (GBS), a post-infectious autoimmune disease

• found in undercooked chicken and unpasteurized milk

• symptoms: diarrhea, severe abdominal pain, nausea, vomiting, and fever

• self-limiting and requires supportive care (hydration and electrolytes)

Yersinia Gastroenteritis or Yersiniosis

• intestinal infection caused by eating contaminated raw or undercooked pork

• caused by Yersinia enterocolitica

• produces an enterotoxin that can survive and grow at refrigerator temperatures

• symptoms: diarrhea, fever, and abdominal pain

  • for older adults, mimics appendicitis

• self-limiting

Clostridium difficile

• gram-positive, anaerobic endospore forming rod

• causes antibiotic-associated colitis and pseudomembranous colitis

• vegetative cells produce exotoxins → tissue damage and diarrhea

• transmitted via fecal-oral route, often in healthcare settings

• infection risk increases after broad-spectrum antibiotic use

• relapse may occur due to endospore germination

Peptic Ulcers

• pathogen: Helicobacter pylori

  • spiral-shaped

• symptoms: ulcers in gastric mucosa

• virulence factors:

  • survives in acidity of stomach by producing urease to neutralize gastric acid

• treatment: antibiotics

• carcinogenic: gastric cancer

Puerperal Fever (Puerperal Sepsis or childbirth fever)

• involves Streptococcus pyogenes (GAS)

• irritation of uterine wall after vaginal delivery → organism enters bloodstream

• uncommon due to improved antiseptic obstetric practices and antibiotics

Group B Streptococci (GBS)

• caused by Streptococcus agalactiae

• causes neonatal sepsis with meningitis

• newborn contaminated via colonized birth canal (transmission)

  • can be present in baby’s blood → sepsis → meningitis

• pregnant women must be regularly screened to be treated with antibiotics

Rheumatic Fever

• caused by Streptococcus pyogenes

• systemic immune response after “Strept Throat” symptoms go away

  • antibodies target and attack the body’s healthy tissues due to molecular mimicry

  • leads to rheumatic fever → damages heart valves and joints; fever, rash, arthritis

• virulence factors: M proteins (generated antibodies) that target healthy tissues through mimicry

Anthrax

• caused by Bacillus anthracis

• found in soil and infected grazing animals

• transmission: skin, inhalation, or ingestion

• symptoms: severe illness and potentially death

• occurs when endospores enter the body → leads to 3 forms of disease

  • cutaneous, pulmonary, and gastrointestinal

• produces two exotoxins (lethal and edema factor) and a protective capsule

• working with animals or products of animals = must keep clean

• prevented by a vaccine

Gas Gangrene

• characterized by the death of body tissues

• caused by Clostridium perfringens, gram-positive and an anaerobe

• occurs when bacteria enter deep, contaminated wounds

• anaerobic environment → production of toxins and enzymes

  • cytotoxin → destroy blood cells and damage tissue → necrosis

• eventually, bacteria will enter the bloodstream → fatal infection

• treatment: surgical debridement and antibiotics

Plague

• caused by Yersinia pestis

• can survive and replicate in macrophages

• found in wild rodents

• transmitted to humans via flea bites (vector)

• bites → lymphatic system → bubonic → buboes (swollen lymph nodes)

• bites → bloodstream → septicemic plague

• respiratory droplets → lungs → pneumonic plague

• treatment: vaccines are available and antibiotics

Lyme Disease

• caused by Borrelia burgdorferi (spirochetes)

  • systemic → spirochetes disseminate into bloodstream

• reservoirs: deer and rodents

• transmitted via ticks onto humans (vectors)

• diagnosis: “bull’s eye rash”

• treatment: early antibiotic treatment

• may develop into carditis and chronic arthritis

Endemic Typhus Fever

• pathogen: R. typhi

  • gram-neg, obligate intracellular

• transmission: arthropod vectors to humans

• symptoms: fever, headache, rash, weakness, and enlargement of liver and spleen

• invades and damages endothelial cells of blood vessels

• NO vaccine, treated with antibiotics, but often remains latent

Epidemic Typhus Fever

• caused by R. prowazekii

  • gram-neg, obligate intracellular

• transmitted via bites of body louse

• bacteria in feces of lice → scratching allows organism through the skin

• reactivation of latent organism possible → Brill-Zinsser disease → milder symptoms

• NO vaccine available; but antibiotic treatment

Rocky Mountain Spotted Fever (RMSF)

• caused by R. rickettsii

  • gram-neg, obligate intracellular

• transmitted via ticks (vectors)

• infects vascular endothelium → systemic vasculitis → petechial rash

• NO vaccine, antibiotics are used to treat infection

Pneumococcal meningitis

• caused by S. pneumoniae

• can infect nasopharynx without symptoms

• virulence factors: capsules and pneumolysins

• vaccines are available against S. pneumoniae

Meningococcal meningitis

• caused by Neisseria meningitidis

  • gram-neg

• can infect nasopharynx without symptoms

• virulence factors: capsules, endotoxins, and pili

• vaccines are available

Hib meningitis

• caused by Haemophilas influenzae type B

• can lead to pneumonia

• can live asymptomatically in upper respiratory tract

• Hib vaccine available

• at-risk: unvaccinated children

Neonatal Bacterial meningitis

• pathogens: GBS, E. coli, L. monocytogenes

• lead to bacterial meningitis in newborns

• transplacental

• at-risk: immunocompromised people and elderly

Listeriosis

• foodborne infection caused by L. monocytogenes

• found in contaminated foods, like cheese and deli meat

• virulence factors:

  • survives and lives in macrophages

  • capable of growing at refrigeration temperatures

• symptoms: flu-like or gastrointestinal symptoms

• Severe diseases, like Listerial meningitis, will target immunocompromised individuals

• bacteria is transplacental → septicemia and meningitis

Tetanus

• caused by Clostridium tetani

  • endospore-forming anaerobe

• infects puncture wounds, causing endospores to germinate

• releases a neurotoxin

  • blocks inhibitory signals in nervous system

  • leads to spastic (sustained) paralysis

• primary symptom: lockjaw

• DTaP vaccine available

  • contains tetanus toxoid

Botulism

• caused by Clostridium botulinum

  • endospore-forming anaerobe

• produces neurotoxin carried on prophage

  • prevents muscle contraction → flaccid paralysis

• ingestion of preformed toxins in improperly canned foods → foodborne botulism

• can also infect anaerobic wounds → wound botulism

• infected infants via honey → floppy baby syndrome (infant botulism)