Microbiology Bacterial Classification

Gram (+) Cocci (PURPLE)Non motileNon-spore formingStaphylococcus (grape like clusters)Staphylococcus aureus MRSAVRSATSST (superantigen)Staphylococcus epidermidis Streptococcus (in little strips)Streptococcus pyogenes Has an M protein that is an important virulence factor, it aids in its attachmentStreptococcus pneumoniae Most common cause of meningitis and otitis mediaGram (+) Bacilli (PURPLE)Divided into:Spore formingBacillusBacillus anthracisCauses anthrax Bacillus cereusCauses food poisoning ClostridiumClostridium tetaniToxin causes tetanus Clostridium botulinumUsed in BotoxClostridium perfringensClostridium difficileNon-spore forming CorynebacteriumListeria
Gram (-) Cocci (PINK/RED)Neisseria Neisseria meningitidis This is the leading cause of meningitis in kids 2-18Neisseria gonorrhoeae2nd most common notifiable bacterial disease in the USNewborns can be infected at birthGram (-) Bacilli (PINK/RED)EnterobacteriaceaeGI tract, primarily in the colon of humans EscheriaMost common cause of UTISalmonella Typically leads to bloody diarrhea ShigellaVibrio CholeraeCampylobacter jejuni
Bacterial Classification : Gram (+) CocciDiseases Caused by the BacteriaOther Information
Staphylococcus aureusMRSA, VRSA
Staphylococcus epidermidisEndocarditis, prosthetic joint infections
Beta-hemolytic Streptococci: - Streptococcus pyogenesPharyngitis, cellulitis, scarlet fever, toxic shock syndrome, necrotising fasciitis
Beta-hemolytic Streptococci: - Streptococcus agalactiaeNeonatal meningitis, neonatal sepsis
Alpha-hemolytic Streptococci:PneumococcusPneumonia, bacteremia, meningitis
Alpha-hemolytic Streptococci:Viridans groupInfective endocarditis*streptococcus mutans is a component of dental plaque
Streptococcus pneumoniaeCommunity acquired pneumonia, meningitis, otitis media, sinusitis, sepsis post-splenectomy
Bacterial Classification : Gram (-) CocciDiseases Caused by the BacteriaOther Information
Neisseria meningitisLeading cause of meningitis in kids 2-18Transmitted via airborne droplets
Neisseria gonorrhoeaeGonorrhea, neonatal conjunctivitisNewborns can be infected at birth
Bacterial Classification : Gram (+) BacilliDiseases Caused by the BacteriaOther Information
Bacillus anthracisAnthraxBioterrorism agent
Bacillus cereusFood poisoning
Clostridium tetaniTetanus
Clostridium botulinumBotulismThis is a paralytic that is used in plastics
Clostridium difficileAntibiotic-associated pseudomembranous colitisThis is the most common cause of hospital acquired diarrhea
Clostridium perfringensGas gangrene, food poisoningPresent in traumatized tissue (war wounds, accidents)
Corynebacterium diphtheriaeDiphtheria
Listeria monocytogenesMeningitis and sepsisTargets these populations: newborns, pregnant women and immunosuppressed adults
Bacterial Classification : Gram (-) BacilliDiseases Caused by the BacteriaOther Information
EscherichiaMost common cause of UTI and Gram (-) sepsisFound in the colon of humans and animals
SalmonellaMost common cause of bacterial enterocolitisTyphoid: typhoid feverNon-typhoid: diarrheaDivided into Typhoid and non-typhoid species
ShigellaEnterocolitis
Bacterial Classification : Curved Gram (-) BacilliDiseases Caused by the BacteriaOther Information
Vibrio CholeraeColera
Campylobacter jejuniPediatric EnterocolitisMay lead to Guillain Barre Syndrome
Helicobacter pyloriGastritis and peptic ulcers
Bacterial Classification : Gram (-) Bacilli Outside of the Enteric SystemDiseases Caused by the BacteriaOther Information
Klebsiella pneumoniaePneumonia, UTI, infrequently bacteremiaPredisposing conditions: advanced age, COPD, diabetes, alcoholism
Pseudomonas aeruginosaSepsis, pneumonia, UTIs
Bacteroides fragilisMost common cause of serious anaerobic infections: sepsis, peritonitis, abscessesMost common cause of intra-abdominal infections
Bacterial Classification : Gram (-) Bacilli in the Respiratory TractDiseases Caused by the BacteriaOther Information
Haemophilus influenzaePneumonia, meningitis, otitis media, epiglottitis
Bordetella pertussisWhooping cough
LegionellaPneumonia
Bacterial Classification :Non-Gram staining bacteriaDiseases Caused by the BacteriaOther Information
Mycobacterium tuberculosisTuberculosis
Mycobacterium bovisGI tuberculosis from unpasteurized milk
Mycobacterium lepraeLeprosy
Mycoplasmas pneumoniaeWalking pneumoniaMost frequent cause of pneumonia in young adults
Borrelia burgdorferi (spirochete)Lyme diseaseMost common vector-borne (tick) illness in the US
Treponema pallidum (spirochete)Syphilis
ChlamydiaeMost common cause of sexually transmitted diseaseOften co-infected with N. gonorrhoeae
Rickettsia rickettsiiRocky Mountain Spotted Fever*endemic via ticks in SE USA

Gram (-) Zoonotic Organisms

  • Francisella: Tularemia
  • Yersinia: Plague
  • Pasteurella multocida: wound infections from dog/cat bites
  • Bartonella: Cat-scratch disease