Bacteriology Gram Negative, Acid Fast, Spirochetes + Mycoplasma Flashcards
What are the groups of gram negative bacterias?
1) Neisseria (pathogenic, diploid cocci)
2) The Enterics – GI tract organisms –> Escherichia, Salmonella, Shigella, Vibrio, Campylobacter, Helicobacter, Klebsiella, Pseudomonas, Proteus, Bacteroides
3) Haemophilus, Bordetella, Legionella –> Respiratory tract organisms
4) Yersenia, Francisella, Brucella, Pasteruella –> Zoonotic diseases – organisms from animals
5) Chlamydia and Rickettsia
6) Spirochetes
Neisseria meningitidis details.
- Meningitis –> leading cause of death from infection in children
- Meningococcemia –> sepsis
1) Capsule
2) Pili
3) Endotoxin (LPS): blood vessel destruction and sepsis –> PETECHIAE - Spreads via respiratory secretions
- Infants aged 6 mos to 2 years of age
- Military recruits
- College freshmen
Neisseria gonorrhoeae details
- Causes 2nd most common reportable bacterial disease
- Pili – adhere to host cells, and have changing antigens
- Neonatal conjunctivitis
- Pelvic inflammatory disease (PID) – infection of:
- Uterus – endometritis
- Fallopian tubes – salpingitis
- Ovaries - oophoritis
Moraxella catarrhalis details.
-In the same phylogenic family as Neisseria
Causes 3 major conditions
1) Otitis media
2) Upper respiratory infection (URI) in adults with chronic obstructive pulmonary disease (COPD)
3) Pneumonia in the elderly
Describe characteristics of the Enterics.
- Either part of normal intestinal flora or cause GI disease
- All transmitted by the fecal-oral route
- Produce: Diarrhea, Various other infections (UTI, pneumonia, sepsis, especially in debilitated patients)
- Associated with being acquired in the hospital
- Can develop antibiotic resistance
Escherichia coli diarrhea details
- Affects infants or adults
- Infants are susceptible due to lack of immunity
- Death can occur due to dehydration
-Severity of illness depends on which virulence factors the strain possesses
Enterotoxigenic E. coli (ETEC) details.
- Travelers’ diarrhea or Montezuma’s revenge
- Pili – virulence factor
- Exotoxin - after binding, it releases exotoxin
- Exotoxin is similar to that released in cholera
- Electrolyte loss and dehydration
- Extremely watery diarrhea –> looks like “rice water”
Enterohemorrhagic E. coli (EHEC) details.
-Pili – virulence factor
-Exotoxin - secretes powerful toxin called Shiga-like toxin (verotoxin) –> Inhibits protein synthesis, causing intestinal epithelial cell death
-Bloody diarrhea with severe abdominal cramps (hemorrhagic colitis)
Example: strain 0157:H7 linked to HAMBURGER MEAT
Enteroinvasive E. coli (EIEC) details.
- Same disease state as that produced by Shigella
- Virulence factor – a plasmid that enables the bacteria to invade through epithelial cells
- INVADES THROUGH THE INTESTINAL WALL causing immune-mediated inflammatory reaction and fever
- Bloody diarrhea with WBCs
Escherichia coli UTI details.
- Travels up urethra to infect bladder (cystitis) and/or the kidney (pyelonephritis)
- Most common cause of UTI
- Most often occurs in women and in hospitalized patients with urethral catheters
- UTI symptoms: Dysuria, Urinary frequency
Escherichia coli meningitis details.
- A common cause of neonatal meningitis
- Most common cause is GBS
- Most susceptible during first month of life
Escherichia coli sepsis details.
- Most common cause of gram-negative sepsis
- Usually occurs in debilitated hospitalized patients
Escherichia coli pneumonia details.
Common cause of hospital-acquired pneumonia
Klebsiella pneumoniae details.
- Encapsulated, non-motile
- Second most common cause of sepsis in hospitals (after E. coli)
- UTI in hospitalized patients with Foley catheters
- Pneumonia in debilitated patients
- 50% have bloody sputum = Red “CURRATE JELLY SEPTUM”
- High mortality
Proteus mirabilis details.
- Very motile gram negative rod
- Present in colon and soil and water
- Common cause of: UTI + Hospital acquired infection (nosocomial)
Enterobacter details
- Motile
- Part of normal intestinal flora
- Can cause hospital-acquired infections
Shigella details.
- Non-motile, always a pathogen
- Humans are its only host
- Transmitted by fecal-oral route via fecally-contaminated water and hand-to-hand contact
- Preschool children, nursing homes
- Similar to enteroinvasive E. coli (EIEC)- both INVADE INTESTINAL EPITHELIUM and release shiga toxin
- Damaged colon can’t reabsorb fluids, causes diarrhea
- Diarrhea with bright red blood and WBCs
Salmonella details
- lives in GI tract of animals
- Always pathogenic
- Infects humans when there is contamination of food or water with animal feces
- Most commonly acquired in the US from CHICKENS and UNCOOKED EGGS
- Most common manifestation is diarrhea (gastroenteritis)
Salmonella typhi details
- Causes Typhoid Fever (enteric fever)
- Invades intestinal epithelial cells + regional lymph nodes
- Can survive inside other cells – a FACULTATIVE INTRACELLULAR PARASITE
- Fever, headache, abdominal pain 1-3 weeks after exposure
- Chronic carriers of S. typhi carry it in their GALLBLADER
Yersinia enterocolitica details
- Acute gastroenteritis
- Animals are a major source
- Humans ingest contaminated food or water
- Can survive and grow in the cold
Vibrio cholera details
- Curved gram-negative rod with single flagellum
- Causes cholera
- Fecally-contaminated water is usual source
- Bacteria attach to cells and release cholera toxin
- Abrupt onset of “rice water” diarrhea – rice water
- Death by dehydration
Campylobacter jejuni details
- One of the 3 most common causes of diarrhea in the world
- Reservoirs are wild and domestic animals and poultry
- Often via contaminated water via fecal-oral route
- Organism invades lining of small intestine
- Bloody, loose diarrhea
