Bacteria Flashcards
Facultative bacteria
can divide independently and on agar plates but enter host cells as part of their pathogenesis
Neisseria, Enterics, Mycobacter, Bacilli, Legionella
Obligate Intracellular Parasites
require host cell resources to multiply
Rickettsial, Chlamydia
Intracellular pathogens
uses infected macrophages for transport around body and evade humoral and surface-innate immunity (actin-based cell-cell spread)
Type 3 secretion systems
establishes intracellular lifestyle. enchances phagocytosis by target cell type or alter the endosome so that lysosomes fail to fuse to it.
Tetracycline
antibiotic that crosses the human cell membrane and remains active. contraindicated in pregnancy
Listeria monocytogenes
facultative intracellular bacterium, causes gastroenteritis. after endocytosis, escapes endosome and uses actin based motility to spread between cells. can cause meningitis in immunosuppressed patients and will complicate pregnancy.
Rickettsia rickettsiae
obligate intracellular bacterium, transmitted by ticks. infects endothelium of blood vessels causing leakage and rocky mountain spotted fever. has virulence factors for adhesion, cell entry, endosomal escape and actin based cell-cell spread
Chlamydia
obligate intracellular pathogen, rugged elementary bodies unpack into larger delicate reticulate bodies after cell penetration. carries T3SS for entry and can convert back into elemetnary bodies. infection can lead to reactive arthritis
Vibrio
curved, Gram (-) rods, ocean dwelling pathogens, results in fecal-oral gastroenteritis
V. cholerae
Vibrio, transmitted to humans by fecal-oral route, secretes choleragen, causes watery diarrhea
H. pylori
Vibrio, causes most stomach ulcers, associated with stomach cancer, produces urease (converts urea to ammonia) which neutralizes stomach acid
urea breath test: patients exhale radiolabeled carbon dioxide
treated with antibiotics, pepto bismol, proton pump inhibitors
Spirochetes
wide variety of transmission (sexual, vector borne, environmental), crosses easily into blood stream, can cross blood-brain barrier leading to meningitis. virulence factors include immune evasion, not very antigenic
no vaccines but easily treated with antibiotics, diagnosed using Argyll-Robertson pupil
Jarisch-Herxheimer reaction
reaction to treatment for Sphyilis and Lyme disease
Sphyilis
Spirochete, 3 stages: painless chancre, rash with flulike symptoms, cardiac or CNS involvement.
Lyme Disease
Spirochete, transmission by ticks, 3 phases: skin infection (rash), immune/neurological issues, fibromyalgia. Treated with doxycycline
Obligate (non-facultative) anaerobic bacteria
derives all their ATP from fermentation, can be either normal flora or soil organisms.
virulence determined by exotoxin expression
Major pathogenic anaerobes
Clostridium (gram positive), actinomyces (gram positive), GNAB (normal flora), actinomyces (normal flora), C. difficile (normal flora)
Enterobacteriaceae
Shigella, E. coli, Salmonella, Yersinia
gram negative, non-sporulating, straight rods, facultative aerobes, catalase positive, oxidase negative, glucose fermenters
fecal oral transmission
M. tuberculosis
acid fast positive, transmission by inhalation, results in granulomas
Atypical mycobacteria
environmentally acquired infection, does not cause TB or leprosy, usually cutaneous infection
M. leprae
slowest growing human pathogen
Hansen’s disease (leprosy) presents on a range from tuberculoid to lepromatous
treated with dapsone and rifampin
Reactive Arthritis
triggered by infection with Shigella, Salmonella, Yersinia, Campylobacter, Chlamydia
Hemolytic uremic syndrome
Infection by shigella or enterohemmorhagic strain of e. coli
Patients positive for Human Leukocyte Antigen (HLA)-B27
“ICU Bugs;” major opportunistic nosocomial pathogens
Klebsiella, Enterobacter, Serratia, Proteus, Providencia, and Morganella
