Gram - Infections Flashcards
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As a general rule, most clinical infections are ____ while most GI infections are ____
Aerobic, anaerobic
Endotoxin
Derived from the LPS protein layer on the outermost membrane of gram - organisms, released upon cell death to cause malaise but rarely fatal
Exotoxin
Substances released by living bacterium, can cause major damage to host and are fatal in large quantities
Periplasmic enzymes
enzymes stored in the space between the outer membrane and cell wall of the gram negative organism, when released are a source of virulence factor in the body as an endotoxin
E. coli is normally found in the GI tract without causing problems, in fact they help metabolize what vitamin?
B2 riboflavin
Most common UTI causing organism
E. coli
Pathology from E coli
- Gastroenteritis/dysentary
- Neonatal meningitis
- septicemia
- UTI
E. coli transmission
Fecal oral route
Enterohemorrhagic E. coli EHEC AKA Shiga toxin producing or Verocytotoxin producing
-Produce toxin similar to shigella, characterized by abdominal pain with initially watery diarhea but can become blood streaked
0157:H7 E coli
Strain responsible most common cause of hemorrhagic colitis and hemolytic uremic syndrome
3 common features of hemolytic uremic syndrome
- Hemolysis
- Thrombocytopenia
- Renal failure
Enterotoxigenic E coli ETEC
Leading cause of traveler’s diarrhea, causes explosive watery, oral fecal route, nonmucoid, nonbloody diarrhea, usually resolved in 3-5 days and self limiting
Enteroinvasive E coli EIEC
Rare in developed countries, watery to bloody stool usually fever and sever abdominal pain
Enteropathogenic e. coli EPEC
Infant diarrhea and impoversihed countries, person to person outbreak, noninvasive but can last 7-15 days
Enteroaggregative E coli EAEC
Relatively new, associated with prolonged diarrhea in pediatrics in developing countries, acute and persistent diarrhea in HIV infected adults, 2nd cause of traveler’s diarrhea, watery stool to bloody, growth retardation and malnutrition
Diffusely adherent e coli DAEC
Watery diarrhea in children over 2 years, developing and developed countries
6 types of e coli
Enterohemorrhagic Enterotoxogenic Enteroinvasive Enteropathogenic Enteroaggregative Diffusely adherant
E coli treatment
Often preventative measures, don’t need antibiotics unless UTI
Campylobacter
Leading cause of bacterial gastroenteritis, and commonly causes traveler’s diarrhea, birds and poultry often reservoirs
Examples of campylobacter species
C. jejuni
C. coli
Key signifier of campylobacter infection
Histologic damage to jejunum, ileum, and colon where mucosal surface appears ulcerated and bloody with crypt abscesses
2 sequelae rare but seen after campylobacter infection
Reactive arthritis
Gulliain Barre’ syndrome
Campylobacter treatment
Often preventative, disease self limiting
Yersinia enterocolitica
Uncommon life threatening in children that can survive in low temps and pasteurized milkm typically manifests as pseudoappendicitis in children
Yersinia pestis
A biological WMD transmitted via flea bites and lab specimens, lead to black death, has 2 manifestations bubonic (high fever, bubo formation, 50% mortality) and pneumonic (fever, pulmonary, 90% mortality)
Yersinia pestis treatment
Aminoglycosides like streptomycin and gentamycin
Vibrio cholerae infection
Secretory diarrhea from cholera toxin 24hrsr after -3 days , can cause rice stools with fishy odor, can kill within 6-12 hours of dehydration
Vibrio cholerae transmission
Water or food contaminated by human fecal matter
2 types of salmonella enterica manifestations
1) Salmonellosis - vomiting, profuse diarrhea, abdominal pain
2) typhoid fever - sometimes individuals are carriers
Typhoid fever presentation
Incubation for 8-14 days, sustained high fever, chills, some develop rose spots
Salmonella typhi treatment
Quinolones - ciprofloxacin
Salmonellosis presentation
Diarrhea, sometimes bloody, fever, cramps, ill appearance 2-7 days
Salmonellosis treatment
Avoid antibiotics (highly resistant, unless bacteremia), avoid anti-diarrheal agents, supportive therapy
Shigellosis
Humans are only reservoir, spread fecal oral, common cause of bacterial gastroenteritis, highly contageous, bloody watery diarrhea, abdominal pain, tenesmus, self limiting
Tenesmus
Constant feeling of having to have a bowel movement despite lack of any actual defacation
Shigellosis treatment
Sel flimiting, oral or IV fluid replacement, antibiotics only if severe
Klebsiella pneumoniae
Most healthy people do not get sick, can be nosocomial in a compromised immune system, part of normal flora
Klebsiella pneumonaie presentation
Thick purulent mucoid sputum (currant jelly), lung abscesses, acute cholangitis
Triad for acute cholangitis
fever, upper right quadrant abdominal pain, jaundice
Klebsiella pneumoniae treatment
Multiple resistance, check susceptibility pattern
Proteus mirabilis
Normal flora that becomes pathogenic in urinary tract (2ndary cause of UTI), wounds, kidney stones (huge and staghorn) often seen in those who have an indwelling catheter
Proteus miribalis treatment
Check sensitivity pattern, highly resistant
Serratia marcescens
Opportunistic pathogen usually nosocomial in nature, rarely invasive, turns red at room temp
Serratia marcesscens treatmnet
Culture and sensitivity needed
Pseudomonas aeruginosa
Opportunistic, nosocomial often infection can also infect hot tubs or ears in healthy, highly virulent, has fruity grape odor
Pseudomonas treatment
Multi drug resistant, serious threat, need expensive or iv drugs to treat
Legionella pneumophilia
Derived from stagnate man made water sources such as air cooling system in legionnaire convention, not contageous person to person, most common atypical pneumonia
2 forms of presentation of legionella pneumophilia
1) Pontiac fever - influenza like, high fever
2) Legionnaire’s - severe pneumonia, fever, dry cough
Heliobacter pylori
Causes peptic ulcer disease, gastritis, most will never develop symptoms, produces urease to colonize gastric mucosa, fecal oral route transmissino
H pylori diagnosis
Urea breath test, blood or stool antigen test
H pylori treatment
bismuth subsalicylate, amoxicillin, metronidazole, clarithromycin, tetracyclin
Brucellosis
Zoonotic, almost all from direct or indirect exposure to animals, very rare, range of symptoms
Brucellosis diagnosis
Blood or other body fluid culture
Brucellosis treatment
Doxycycline and rifampin, bactrim
Tularemia
Rabbit fever, transmitted via skin contact with infected animals, inhalation of aerosols, very virulent, can survive in macrophages, difficult to diagnose
Tuleremia treatment
Streptomycin, gentamicin, doxycycline, cipro
Pasteurella multocida
Transmitted by many domestic or wild animal scratch or bite, ability to alter shape and size
Pasteurella treatment
Amoxicillin,3rd gen cephalosporin
Haemophilus 4 species
Haemophilus influenza A or B, ducreyi, haemolyticus
Haemophilus characteristics
Found in normal flora, requires high CO2 low O2, resistance to PCN
Most common types of invasive disease cause by H influenza
Meningitis, epiglottitis
Haemophilus ducreyi
Chancroid forming, genital ulcer disease
Haemophilus treatment
amoxacillin, if resistant 2nd or 3rd gen cephalosporin
Hamophilus influenza B has a ____ available
vaccine
Niesseria gonorrhoeae
2nd most common STD in US, intracellular diplococci, growing resistance to B lactamase, reportable, screen high risk anually
Niesseria gonorrhoae infection
Cervicitis/PID/urethritis, pharyngitis, neonatal conjunctivitis (can’t see, can’t pee, can’t climb a tree), fitz hugh curtis syndrome
Niesseria gonorrhoae treatment
Ceftriaxone, azithromycine or doxycycline, cipro
Fitz hugh - curtis syndrome
Rare disease found almost exclusively in women, inflammation of membrane lining stomach and the tissues surrounding the liver,
Niesseria meningitidis
Inflames meninges, presents as headache, stiff neck and feer, prompt treatment required
Niesseria meningitidis treatment
Vancomycin
Niesseria meningitidis diagnosis
Gram stain CSF
