Test 2 Flashcards
What are enterobacteriaceae?
-enteric
-gram neg
-non-spore forming rods
-natural habitat is the intestinal tract of humans and animals
What are the 2 types of enterobacteriaceae?
1) coliforms
2) non-coliforms
What are coliform bacteria?
-type of enterobacteriaceae
-can be normal flora or pathogenic
-ferment lactose
-ex: E. Coli or K. Pneumoniae
What is non-coliform bacteria?
-type of enterobacteriaceae
-can be normal flora or pathogenic
-non-lactose fermenters
Is E.coli an enterobacteriaceae? If so, what type?
Yes, it’s a coliform bacteria
What diseases are caused by E.coli?
-UTIs
-epidemic diarrhea of newborns
-opportunistic infections
All of these can happen when E.coli leaves the GI
Is E. coli gram neg or pos? What shape is it? What is its significance?
-gram neg
-motile rod
-competitively discourages growth of possible pathogenic organisms in the colon
coli= colon
human colon contains E.coli as part of its normal flora, however other serotypes can be pathogenic and certain enteropathogenic strains are troublesome to newborns
What is the #1 cause for UTIs in women?
e. coli
What is enteroinvasive E. coli (EIEC)?
identical to shigellosis with profuse diarrhea and high fever
What is enterotoxigenic E. coli (ETEC)?
E. coli penetrates the intestinal epithelium and produces 2 enterotoxins that causes gastroenteritis
What is the most common bacterial form of “traveler’s diarrhea”?
enterotoxigenic E. coli (ETEC)
What is enteropathogenic E. coli (EPEC)?
-infection occurring during birth
-important cause of diarrhea in infants especially when sanitation is poor
What is enterohemorrhagic E.coli (EHEC, also called E. coli O157:H7)? What are its symptoms?
test q
-the most dangerous of pathogenic strains
-food-borne illness
-exists in the intestines of healthy cattle and causes no disease in these animals, but slaughtering them brings the pathogen to beef products
-major source of transmission is undercooked ground beef
-causes severe blood diarrhea
-uncomplicated cases resolve within 5-10 days
What is hemolytic uremic syndrome?
caused by enterohemorrhagic E.coli (EHEC, also called E. coli O157:H7)
its in older adults, young children, or the immunocompromised that may develop complications involving the kidneys and leading to kidney failure
What is the treatment for E. coli bacterial infections?
antibiotics
What samples can be collected for E.coli diagnostics?
-urine sample will show its a gram neg bacteria
-stool sample
How can you prevent E. coli infections?
-care in choosing food and water
-avoiding unpasteurized products
-thorough cooking of ground beef
Proteus sp. are enterobacteriaceae. Are they coliform or non-coliform bacteria?
all 4 species are non-coliform
What diseases are caused by Proteus sp.?
-UTIs
-bacteremia
-pneumonia
-focal lesions in debilitated patients
Are the Proteus sp. gram neg or pos? What shape is it? Where are they considered normal flora?
-gram neg
-pleomorphic rods (pleomorphic= different forms, this bacteria was named after Greek God Proteus who took shape of many forms)
-found in intestinal tract
-produce infections only when bacteria leave the intestinal tract
What is the pathogenicity of Proteus sp.?
-encountered most frequently in UTIs and wound infections
-seen usually in immunocompromised patients
-normal Proteus sp. are present in very small numbers in the intestinal tract
-at times it may be present in large numbers and cause disease which may be associated with excess oral antibiotic therapy
-proteus produces urease which makes the pH of urine more alkaline promoting stone formation (kidney stones)
What is the treatment for Proteus sp.?
antibiotics
can first do blood work or urine sample to confirm
Salmonella is comprised of 2 species. What are they?
1) salmonella enterica (human pathogen, subdivided into 6 subspecies and serotypes with unique virulence properties based on O antigen which is lipid A associated, H antigen which is a flagellar protein or Vi antigen which is a capsular polysaccharide bacteria)
2) salmonella bongori (animal pathogen)
Are the salmonella species an enterobacteria?
yes
Salmonella typhi is a subspecies for salmonella enterica. What disease does it cause and is it pathogenic?
-pathogenic
-causes typhoid fever (enteric fever)
Salmonella typhi is a subspecies for salmonella enterica. Is S. typhi a gram neg or pos bacteria? What shape is it?
-gram neg bacteria
-rod shaped
Salmonella typhi is a subspecies for salmonella enterica. S. typhi is motile with ______________ flagella
peritrichous
Salmonella typhi is a subspecies for salmonella enterica. How is S. typhi transmitted?
via fecal oral route through contaminated food or water
typhoid Mary worked as a cook and was the first person in US identified as an asymptomaic carrier of this pathogen
the ingested organisms reach the small intestine, enter the lymphatics and then enters the blood stream to many organs
the organisms multiply in the intestinal lymphoid tissue and are excreted in stools
incubation period is 10-14 days
bacteria will enter lymphatic tissue in GI and multiply here which can penetrate bowel and cause digestive absorption problems and cause leaky bowel
Salmonella typhi is a subspecies for salmonella enterica. Is S. typhi common in US?
no not anymore, due to good sanitation practices
Salmonella typhi is a subspecies for salmonella enterica. What are the S&S of S. typhi?
-fever
-malaise
-headache
-constipation
-myalgia
-nausea
-abdominal pain
-rash called rose spots found on chest and abdomen
principle lesions are hyperplasia and necrosis of lymphoid tissue (peyer’s patches), hepatitis, necrosis of the liver, and inflammation of the gallbladder and other organs
following an infection, 5% continue to harbor and excrete organisms for a year or more without symptoms
Salmonella typhi is a subspecies for salmonella enterica. Is S. typhi severe?
it can be
Salmonella typhi is a subspecies for salmonella enterica. How is S. typhi diagnosed?
-primarily clinical
-blood and stool cultures within first week of onset (positive in 85-90% of cases)
-PCR test
-salmonella shigella (SS) agar favors growth of these organisms over other coliforms
-bismuth sulfite medium permits rapid detection of S. typhi, which forms black colonies from production of H2S
-widal test is an Ab aggulation test that will build clumps if serum has the bacteria in it
-serological testing is not definitive and is used only in poor areas of the world where blood cultures are not readily available
What is the tx and prevention for S. typhi?
tx: antibiotics
prevention: vax for travelers
Salmonella enterica ssp. Paratyphi A and B causes what disease?
paratyphoid fever (enteric fever)
Is Salmonella enterica ssp. Paratyphi A and B gram neg or pos? What shape is it?
both are gram neg rods
Salmonella enterica ssp. Paratyphi A and B both cause paratyphoid fever (enteric fever). What is it and how is it transmitted?
-causes enteric fever but the disease is milder and shorter duration than typhoid fever from S. typhi
-transmitted by means of contaminated water and food
What disease does Salmonella enterica ssp. typhimurium cause?
septicemic enteric fever
Is Salmonella enterica ssp. typhimurium gram neg or pos? What shape is it?
gram neg rod
Who does Salmonella enterica ssp. typhimurium infect with septicemic enteric fever? How is it transmitted?
-cattle
-poultry
-pigs
-pets (turtles, parrots, etc)
the organisms almost always enters via the oral route, usually with contaminated food or drink
What are the S&S for septicemic enteric fever caused from Salmonella enterica ssp. typhimurium? How is it treated?
-nausea
-diarrhea
-abdominal cramping
-septicemia
tx: antibiotics
What disease is caused by salmonella enteritidis (salmonella enterica serotype enteritidis)?
salmonella gastroenteritis
Is salmonella enteritidis (salmonella enterica serotype enteritidis) gram neg or pos? What shape is it?
gram neg rod
What is the mode of transmission for salmonella enteritidis (salmonella enterica serotype enteritidis)?
-anal oral route
-from contaminated foods that have not been properly cooked or pasteurized like meat, eggs, milk, water, ice cream
-most often from poultry
-contaminated water can also be a problem
-animals are the main reservoir and it affects many animals like poultry, cattle, swine, sheep, rats, dogs, cats, mice, turtles, and birds
note: this is an animal disease with humans being secondarily infected
What is salmonella gastroenteritis caused by salmonella enteritidis (salmonella enterica serotype enteritidis)? What are the S&S?
-FBI
-bacteria is ingested (its an infection) with limited multiplication and no invasion of host tissue (DOES NOT CAUSE SEPTICEMIA)
-bacteria remains in GI
-this is unusual for bacteria and overtime can start to produce endotoxins from the cell wall (lipopolysaccharide with lipid A irritates the GI tract and can cause fever) within 6-48 hours of infection
S&S:
-fever
-abdominal pain
-diarrhea
-nausea
-vomiting
What is the 2nd major cause of FBI in US?
salmonella enteritidis (salmonella enterica serotype enteritidis) causes salmonella gastroenteritis
What is the treatment and prevention for salmonella gastroenteritis caused by salmonella enteritidis (salmonella enterica serotype enteritidis)?
tx:
-replacement of electrolytes is usually enough
-antibiotics may be needed if severe case
prevention:
-adequate cooking of meat and boiling water can eliminate the problem
Shigella sp. has 4 subspecies but we only have to know one. What is this one subspecies and what disease does it cause?
S. dysenteriae causes shigellosis (bacillary dysentery)
Is S. dysenteriae (shigella sp.) gram neg or pos? What shape is it?
gram neg non-motile rod/bacillus
What is the source of infection for S. dysenteriae (shigella sp.)? What is the mode of transmission?
-human intestine is the source
-upon recovery a few people may remain as chronic intestinal carriers and may have recurrent bouts of the disease
-mode of transmission is fecal oral route via contaminated food or water
S. dysenteriae (shigella sp.) causes shigellosis (bacillary dysentery). What are the characteristics of this disease?
-S. dysenteriae is the most severe of the shigella sp. and produces an enterotoxin AND a neurotoxin
-inflammation and necrosis of large intestine, but invasion into bloodstream is rare
-toxic products of bacterial cell wall (lipid A) irritates causing ulceration with some epithelial cell penetration
-disease ranges from mild transient diarrhea to full blown dysentery
-inflammation of large intestine is accompanied by gripping pain, constant desire to evacuate the bowels (tenesmus, which means constant need to be on toilet), diarrhea containing blood/mucus/pus
-fever, water loss and electrolytes imbalance with weight loss
-patients may die 1-2 days after symptoms appear
-more commonly, symptoms last about a week, and slowly abate, many cases are self-limiting
-the young and old are the most frequent victims
How is shigellosis (bacillary dysentery) caused by S. dysenteriae (shigella sp.) diagnosed?
culture organism from feces
What is the treatment for shigellosis (bacillary dysentery) caused by S. dysenteriae (shigella sp.)?
-antibiotics
-fluid replacement bc of electrolyte imbalance
What disease is caused by vibrio cholera?
cholera
Is V. cholera gram neg or pos? What shape is it?
-gram neg
-motile comma shaped rod
How is V. cholera transmitted?
-fecal oral route
-water borne disease
-better sanitation= less frequent cases of cholera
-humans are the only host, V. cholera does not affect animals
What are the characteristics of cholera caused by V. cholera?
-not an invasive infection
-bacteria does not reach bloodstream, will remain in GI
-50% of infections are asymptomatic
-for those with symptoms, there is sudden onset of nausea and vomiting and profuse diarrhea with abdominal cramps
-the cell wall of V. cholera has an endotoxin which is an enterotoxin that is secreted and results in enormous our-pouring of diarrhea, fluids, and electrolytes
-the diarrhea is referred to as RICE STOOLS
-this rapid loss of fluid and electrolytes leads to severe dehydration, circulatory collapse (blood volume decreases and heart has to pump faster/harder), and anuria (no urine production)
-mortality rate w/o treatment is 25-50%
What is the treatment for cholera caused by V. cholera?
-water and electrolytes!!!!!!
-antibiotics are secondary
generally speaking, what is the difference between bacterial infections and toxins?
infections take longer, whereas toxins can hit within a couple hours
and bc the onset is faster, toxins usually are more vomit prone, whereas infections are more diarrhea prone
What disease is caused from vibrio parahaemolyticus?
gastroenteritis (FBI, usually acute)
Is vibrio parahaemolyticus gram neg or pos? What shape is it?
-gram neg
-comma shaped rod
vibrio parahaemolyticus is a marine organism requireing a high salt conc. What is this called?
halophile organism
How is gastroenteritis transmitted caused by vibrio parahaemolyticus?
ingestion of contaminated seafood such as raw fish or shellfish, most commonly shellfish
What are the characteristics of gastroenteritis caused by vibrio parahaemolyticus?
-incubation period of 12-24 hours
-N/V, abdominal cramps, fever, and water to blood diarrhea
-fecal leukocytes are present
-the gastroenteritis tends to subside in 1-4 days w/ no treatment other than restoration of water/electrolyte balance
-most common in Asia and other places people eat raw seafood
What is the treatment and prevention for gastroenteritis caused by vibrio parahaemolyticus?
prevention: adequate cooking of seafood
tx: restoration of electrolyte balance
What diseases are caused by vibrio vulnificus?
-severe wound infections
-bacteremia
-gastroenteritis
Is vibrio vulnificus gram neg or pos? What shape is it? How is it transmitted?
-gram neg
-comma shaped rod
-found in oysters/shellfish especially in warm months
-commonly infects fishermen
What are the pathogenicity characteristics of vibrio vulnificus?
severe wound infections
-seen in both normal people and immunocompromised pts who are in contact with infected water
-can be mild but progress rapidly with cellulitis, myositis, and necrosis
bacteremia
-occurs in pts who eat infected oysters
-seen in alcoholics or pts with liver disease
-about 50% die
gastroenteritis
-FBI
infection often proceeds rapidly with development of severe disease
What is the treatment for severe wound infections, bacteremia, and gastroenteritis caused by vibrio vulnificus?
antibiotics
What type of enteric bacteria is K. pneumonia?
test q
coliform bacteria
What diseases are caused by K. pneumonia?
test q
pneumonia and UTIs
Is K. pneumonia gram neg or pos? What shape is it? What other bacterial characteristics does it have?
-gram neg rod
-has prominent capsule which is virulent
-bacterial strains w/o capsule do not cause disease
-opportunist present in respiratory tract and feces in about 5% of normal people
What are the pathogenicity characteristics of pneumonia caused by K. pneumonia?
test q
-acquired by droplets
-may cause primary or secondary disease in alcoholics or people with COPD
-characterized by rapid onset and gelatinous reddish-brown sputum called red currant jelly
What is treatment for K. pneumonia?
antibiotics
Which bacteria is the #1 cause of most classic opportunistic infections?
pseudomonas aeruginosa (blue pus organism)
Which infections is pseudomonas aeruginosa associated with?
wound and burn infections
Is pseudomonas aeruginosa gram neg or pos? What shape is it?
-gram neg
-motile rod
Pseudomonas aeruginosa is considered normal flora. Where? Where else is it found
-normal flora in GI
-seen in moist environments like nature and in hospitals (nosocomial infection)
What pigment is produced by pseudomonas aeruginosa?
-blue pigment called pyocyanin
-wound, environment around it, etc will appear blue
-literally called “blue pus’
What are the pathogenicity characteristics of pseudomonas aeruginosa?
-pili extend from cell membrane to promote attachment
-lipopolysaccharide layer exists in many phenotypes and is responsible for many of the endotoxin properties of organism
-most isolates produce exotoxins which may be related to pathogenicity
-pathogenic only when introduced into areas devoid of normal defenses like tissue damage, use of IV, urinary caths, or neutropenia is present from chemotherapy
-infection is most prevalent in severe burn victims
-also implicated in wounds, UTIs and pneumonia particularly in the immunocompromised
What is hot tub folliculitis?
-caused by pseudomonas aeruginosa
-skin infection of the hair follicles
-happens when in contact with contaminated water
-can happen in also whirlpools and waterslides, not just hot tubs
What is the diagnosis and treatment regimen for wound and burn infections of pseudomonas aeruginosa?
diagnosis: culture of specimens
tx: combo of antibiotics
What diseases are caused by Y. pestis?
-bubonic plague (black death)
-septicemic plague
-pneumonic plague
Is Y. pestis gram neg or pos? What shape is it? What other microbio/epi characteristics does it have?
-gram neg
-rod
-zoonotic organism
-can be used in bioterrorism
-primarily a disease of rodents (reservoirs) like rats and squirrels
-flea vector, flea will bite on human and cause infection
What are the other names for the black death?
-pestilence
-great plague
-the plague
-black plague
note: one of the most devastating pandemics in history
Which plague caused by Y. pestis is the most common? What is it?
bubonic plague
-bite of flea initiates infection
-bacteria infects lymphatic system and the lymph nodes become inflamed forming buboes (enlarged enflamed lymph nodes)
-hemorrhages result in giving skin a black splotchy appearance
What is the septicemic plague caused by Y. pestis?
-bacteria enters bloodstream rather than lymphatic system
-occasionally will start as bubonic plague and then transition into septicemic plague
-almost always fatal w/o treatment of antibiotics
What is the pneumonic plague caused by Y. pestis?
-can be caused by primary or secondary infection
-primary is inhaling the plague bacteria
-secondary is septicemic plague spreading into lung tissue
-pneumonic plague is very aggressive
-antibiotics are needed within 24hours of onset to prevent death
How is bubonic plague caused by Y. pestis spread?
buboes > thoracic duct > blood > spleen > additional lymph nodes