Exam 2 Study Deck Flashcards
what is included in the upper urinary tract
kidneys
adrenals
ureters
what is included in the lower urinary tract
bladder
urethra
who, men or women, are more susceptible to urinary tract infections
women - they have a shorter urethra
why are urinary tract infections more common in older men than younger men
older men (60+) experience benign hyperplasia of the prostate which can obstruct urine flow
what is pyelonephritis
kidney infection most commonly caused by E. coli
symptoms include: fever, flank pain, frequency, urgency, dysuria (pain), and systemic signs like vomitting and diarrhea
what is cystitis
bladder infection most commonly caused by E. coli
symptoms include: dysuria (pain), frequency, urgency, and bloody/cloudy urine
what is urethritis
urethral infection most commonly caused by a sexually transmitted organism (chlamydia or gonorrhea)
symptoms include: dysuria (pain) and frequency
what is prostatitis
inflammation of the prostate gland most commonly caused by E. coli
name five normal organisms of the flora of the urinary system
staphylococcus
streptococci
lactobacilli
diptheroids
neisseria
what is the most common organism to be community acquired
E. coli
what is important about hospital acquired UTI’s
common due to catheterization procedures
often very antibiotic resistant making them hard to treat
what are the five main complicated community acquired organisms
proteus
pseudomonas
klebsiella
enterobacter
serratia
what is an ascending infection
most common type of infection route
infection that travels superiorly within the urinary tract
most commonly caused by colonization of GI bacteria in the vaginal canal or periurethral area
what is hematogenous spread
blood borne route of spread to the urinary tract
kidney infections caused by which three organisms most often indicate hematogenous spread
yeast - Candida albicans
TB
staph. aureus
what is lymphatic spread
least common route
bacterial spread to the urinary tract from the lymphatics
originating from retroperitoneal abscesses and severe rectal infections
describe this host defense against UTI’s: urine
its conditions inhibit growth or organisms
low pH
high urea
describe this host defense against UTI’s: flushing
we are constantly peeing which flushes out organisms before they can cause infection
describe this host defense against UTI’s: bladder mucosa
has antibacterial properties to prevent infection
describe this host defense against UTI’s: valve mechanism
junction of ureter and bladder acts like a valve to prevent reflux of urine back into the ureter which can cause infection
describe this host defense against UTI’s: host immune response
urothelial cells that come into contact with bacteria trigger an immune response
cytokines are released which activate the complement pathway
what are the 5 main host defenses against UTI’s
urine environment
flushing
bladder mucosal surface
valve mechanism
host immune response
what are the 5 main microorganism virulence factors for urinary tract infections
pathogenicity islands
adherence factors
urease
motility
K antigen production
describe this microorganism virulence factor: pathogenicity islands
genome sequences in organisms associated with virulence
describe this microorganism virulence factor: adherence factors
organisms have things like pili and can make adhesins which allow them to stick better to the host
describe this microorganism virulence factor: urease
certain organisms can make urease
urease will hydrolyze urea which increases pH level and stimulates growth of kidney stones
describe this microorganism virulence factor: motility
motility of microorganism thanks to things like flagella allow it to more easily ascend the urinary tract and cause infection
describe this microorganism virulence factor: K antigen production
microorganism’s production of K antigen can protect them from being phagocytized
what are 6 things in urine that can help diagnose a UTI
leukocyte esterase
nitrites
WBC
WBC casts
RBC
physical bacteria
what are the three main groups of organisms found in urine samples
E. coli
enterobacter
KES group (klebsiella enterobacter serratia)
what is the clean-catch midstream specimen collection method
most common method
urine is collected by the patient mid stream to prevent contamination with normal flora
what is the straight catheterized urine collection method
urine is collected from the bladder through a catheter
less contamination, assuming catheterization is done in a sterile manner
what is the suprapubic bladder aspiration collection method
urine is withdrawn from the bladder into a syringe through a percutaneous needle
full bladder is needed
usually done on infants or those hard to collect a sample from
less contamination, assuming done in a sterile manner
what is the indwelling catheter collection method
urine is retrieved from long term catheterized patients
catheter port is washed with 70% alcohol before procedure
urine should not be taken from the collection bag as this could skew results
how is a gram stain used in the detection of a UTI
gives the clinician a preliminary to help them decide which antibiotic to start the patient on
how are urine cultures processed
pre-calibrated loop (1:1000 - very small) is used to place the cultures on Maconkey, 5% sheep blood, or CNA agar
plates are incubated for 2 days at 35 degrees centigrade
what bacteria count is considered a true UTI
> 10^5 CFU/ml
what do urine collection tubes contain
preservatives like boric acid which will stabilize the urine for 48 hours and prevent contamination
are anerobes or aerobes more common in the normal adult GI flora
anaerobes
what are the 6 host factors that help prevent GI infections
acidity of stomach
peristalsis
mucous
normal flora
follicles (peyer’s patches)
cells that destroy bacteria
describe this host factor that prevents GI infections: follicles
specialized cells in the GI tract that make up Peyer’s patches when clumped together
cell types include: M, B, and T cells and macrophages
when microorganisms interact with these cells, IgA is released which will destroy them
describe this host factor that prevents GI infections: cells
3 main cell types that help destroy bacteria:
phagocytic cells
IgA
eosinophilic cells
describe esophagitis
infection of the esophagus, usually associated with an underlying illness (HIV)
symptoms: painful swallowing
what are the three organisms that can cause esophagitis
candida albicans
herpes simplex (HSV)
cytomegalovirus
describe gastritis
inflammation of the gastric mucosa
symptoms: nausea, pain, vomiting, burping, and fever
which organism causes gastritis
helicobacter pylori
describe proctitis
inflammation of the rectum
symptoms: itching and mucoid discharge
which four organisms can cause proctitis
STI’s:
chlamydia
herpes simplex (HSV)
syphillus
gonorrhea
which organism can cause Crohn’s disease
mycobacteria
what are the three main symptoms of Crohn’s disease
diarrhea
pain
cramping
what are three microbial factors that allow organisms to cause disease within the GI tract
1.) enterotoxin production changes the balance of water and electrolytes leading to massive fluid secretion in the small bowel
2.) invasion and destruction of host cells in colon
3.) penetrate of intestinal mucosa and spreading which can cause systemic infections
what are the five pathogenic mechanisms that bacteria employ to cause GI infections
enterotoxin
cytotoxin
neurotoxin
attachment
invasion
describe this pathogenic mechanism that causes GI infections: enterotoxins
production of enterotoxins causes release of electrolytes and fluid into the lumen of the small bowel
symptoms: watery diarrhea
organisms: vibrio cholerae + salmonella
which organism produces the most potent enterotoxin
vibrio cholerae - causes watery diarrhea
describe this pathogenic mechanism that causes GI infection: cytotoxins
production of cytotoxins causes damage to intestinal cells and causes them to slough away, thus leaving unprotected areas
symptoms: dysentery, pain, cramps, and tenesmus (painful straining)
organisms: clostridium difficile + shigella
describe this pathogenic mechanism that causes GI infection: neurotoxins
production of neurotoxins causes food poisoning
symptoms: vomitting and diarrhea
organisms: bacillus cereus + clostridium botulinum
what is the epidemiology of E. coli
traveler’s diarrhea
food and waterborne illnesses
what is the epidemiology of salmonella
traveler’s diarrhea
food and water borne outbreaks
immunocompromised hosts
what is the epidemiology of shigella
institutional setting
food and water born outbreaks
immunocompromised hosts
what is the epidemiology of campylobacter
institutional setting
traveler’s diarrhea
food and waterborne outbreaks
immunocompromised hosts
what is the epidemiology of noroviris and rotavirus
institutional setting
traveler’s diarrhea (rotavirus)
what is the epidemiology of vibrio cholerae
traveler’s diarrhea
what is the epidemiology of clostridium difficile
institutional setting
what is the epidemiology of cryptosporidium
institutional setting
food and water born outbreaks
immunocompromised host
what is the epidemiology of Giardia
institutional setting
food and water borne outbreaks
immunocompromised hosts
what are some features of clostridium difficile
gram stain: gram positive
tests: PCR or EIA
epidemiology: antibiotics killing good bacteria
symptoms: watery diarrhea
what are some features of shigella and salmonella
gram stain: gram negative
tests: culture
epidemiology: contaminated food
symptoms: shigella: dysentery; salmonella: diarrhea, enteric fever, and bacteremia
what are some features of campylobacter
gram stain: gram negative
tests: culture
epidemiology: undercooked chicken
symptoms: blood, gastritis, and septicemia
what are some features of vibrio parahemolyticus
gram stain: gram negative
tests: hard to culture - with salt
epidemiology: contaminated water or seafood
symptoms: gastroenteritis
what are some features of yersinia enterocolitica
gram stain: gram negative
tests: hard to culture - bullseye on plate
epidemiology: undercooked pork
symptoms: presents as appendicitis
what are some features of norovirus and rotavirus
tests: PCA or EIA
epidemiology: contaminated food and water
symptoms: vomitting, nausea, and diarrhea
incubation period: 2 days (rotavirus)
what are some features of Giardia (parasite)
tests: staining, PCR, and EIA
epidemiology: fecal contamination
symptoms: diarrhea and cysts
what are the 4 routes of infection transmission to the brain
hematogenous
direct spread
anatomic defect
direct intraneural
what is hematogenous spread to the brain
most common route of infection
bacteria enters the subarachnoid space through the choroid plexus
ex. purulent meningitis caused by hematogenous spread of staph. aureus
what is direct spread to the brain
extension of an infection of close proximity to the CNS
ex. middle ear infection (otitis media) can spread to the brain because it’s so close
what is the anatomic defect route of spread to the brain
defects within CNS structures due to things like surgery can allow organisms to reach the brain and cause infection
ex. encephalocele
what is direct intraneural spread to the brain
infections travel along the nerves to get to the brain
ex. rabies and herpes virus
what is purulent meningitis
bacterial caused, acute inflammatory exudate with lots of polymorphonuclear cells
mostly affects the ventricles
what is aseptic meningitis
increase in lymphocytes or mononuclear cells in the CSF that is usually caused by viruses
what are two host defenses against purulent meningitis
blood brain barrier
age of patient
what is the blood brain barrier
choroid plexus arachnoid membrane and the cerebral microvascular endothelium prevent the passage of infectious agents into the CSF
which age of patient is at most risk for developing purulent meningitis
neonates because they are immunocompromised
they can get infections like strep. and E. coli while being delivered
what are the three virulence factors that allow microbes to enter the CNS and cause purulent meningitis
secretion of IgA proteases - destroy host’s IgA allowing them to attach to the epithelium
antiphagocytic capsule helps them evade destruction by the host immune system
breaking down microvascular endothelial cells of blood brain barrier, allowing them to penetrate the CSF
what are the 6 main symptoms of purulent meningitis
stiff neck
fever
headache
nausea
vomitting
altered mental status
what are the three clinical factors used to diagnose purulent meningitis
CSF: lots of polymorphonuclear cells (neutrophils)
decreased glucose
increase protein
what are the 5 main symptoms of aseptic meningitis
stiff neck
fever
headache
nausea
vomitting
what are the two factors used to diagnose aseptic meningitis
increase in lymphocytes/mononuclear cells
negative bacteria/fungi cultures
which organism causes purulent meningitis in young adults
neisseria meningitis - acquired from communal areas like jails and dormitories
which 4 organisms can cause purulent meningitis in adults
neisseria meningitis
strep. pneumo
listeria
staph. aureus
which underlying condition can cause chronic meningitis
HIV
which two non viral organisms can cause aseptic meningitis
syphilis
spirochetes
give five examples of organisms that can cause chronic meningitis
TB
cryptococcus
candida
actinomyces
brucella
mostly fungi
what is encephalitis
inflammation of the brain parenchyma usually due to a virus
what is meningoencephalitis
meningitis (inflammation of the meninges) that occurs with encephalitis (inflammation of brain parenchyma)
what are the two most common organisms that cause encephalitis
enteroviruses - coxsackievirus and echoviruses
what are two organisms that can cause meningoencephalitis
amoebae - naegleria fowleri and acanthomoeba
how is CSF collected
through lumbar puncture
10-15 ml of CSF is placed into 4 sterile tubes
specimen is brought immediately to the lab and kept at room temperature
what tests are done on a CSF culture
cell count, glucose, and protein levels
cytospun for 15 minutes
gram stained
plated on chocolate media, BAP, and thioglycolate broth
how are the results reported for a CSF culture
gram stain results read and reported immediately
bacterial cultures are help for 3 days
positive cultures called immediately
what are wet preps used for
used to detect amoebas in the case of naeglaria fowleri
what is India ink and latex tests used for
India ink: stain that will show cryptococcus neoformans and its capsule
latex test: detects polysaccharide capsular antigen in crypto coccus neoformans
why are molecular methods involving PCR so good to use for CSF specimens
rapid and have excellent specificity and sensitivity
they can also detect multiple different types of organisms at once
what is bacteremia
bacteria in the bloodstream, usually due to a wound or infection
produces mild symptoms and usually requires no treatment
what is septicemia/sepsis
organ injury or damage in reponse to a bacterial infection
what is septic shock
when sepsis leads to dangerously low blood pressure and abnormalities in cellular metabolism
why is it important to be urgent when working up a positive culture
timely identification of the organism and its susceptibility provides information to the clinician that will help them administer appropriate antimicrobial therapy
what are the results of inappropriate antibiotic use
antibiotic won’t kill the organism
they develop resistance
using a more expensive one when you don’t need to
using an antibiotic that is more toxic to the patient than necessary
what are the three types of bacteremia
transient
consistent
intermittent
what is transient bacteremia
bacteria are introduced spontaneously or due to minor events like brushing the teeth
what is continuous bacteremia
organisms are released into bloodstream at a constant rate
ex. septic shock and endocarditis
what is intermittent bacteremia
organisms are released into the bloodstream at an intermittent rate
ex. meningitis and pneumonia
what are the two types of blood stream infections
intravascular and extravascular
what is the origin of intravascular blood stream infections
cardiovascular system
what are four examples of intravascular blood stream infections
infective endocarditis
mycotic aneurysm
suppurative thrombophlebitis
catheter-associated bacteremia
what is the most common organism to cause infective endocarditis
viridan streptococcus
what is a mycotic aneurysm
typically a bacterial infection that damages that aortic endothelium leading it to bulge and burst
what is suppurative thrombophlebitis
inflammation of the wall of a vein which allows a clot to form
which organism most commonly causes catheter-associated bacteremia
staph. epidermis (catalase+, coagulase-)
what is an extravascular blood stream infection
bacteria gets to the circulation through the lymphatic system
most common cause for bacteremia
what are the three most common extravascular portals of entry which lead to extravascular blood stream infections
genitourinary tract
respiratory tract
abscesses
what are the two main GI tract organisms to cause extravascular blood stream infections
E. coli
enterococcus
what are the three main organisms that cause intravenous catheter-associated bacteremia
staph. epidermidis
staph. aureus
mallazezia furfur
how do bacteria cause intravenous catheter-associated bacteremia
they enter the catheter from the skin and get to the blood
they migrate from the inside of the catheter into the blood
how is intravenous catheter-associated bacteremia diagnosed and treated
most commonly, patients will have a fever or redness at the site
treatment is to removed the catheter and replace with a new one - antibiotics can be given if infection is severe
what is unique about malazessia furfur
it is a yeast that is normally found on the skin
it is lipophilic so it flourishes at the parenteral nutrition (intravenous nutrition) site
it’s hard to grow because of it’s strict lipid requirement - use olive oil to grow
helmet shaped
which 5 organisms in the blood can indicate a neoplasm
clostridium septicum
strep. bovis
pleisiomonas shigelloides
aeromonas hydrophila
campylobacter
what is often used when taking blood cultures for bacteria and how are they used
blood bottles - they are loaded into an instrument that will monitor the presence of bacterial growth for 5 days at 10 minute intervals
how does the Bactec blood instrument detect bacterial growth in blood bottles
detected of CO2 production using a CO2 sensitive membrane at the bottom of the bottle
-organism releases CO2 which reacts with dye in vial sensor
-LED activates fluorescent material in sensor
-photo detector reads fluorescence
-data from detector is analyzed by row board and positivity analysis is performed
-positive vial is announced in multiple ways
what are two instruments that can perform identifications straight from the blood bottles
MALDI-TOF and PCR
more timely than the Bactec blood instrument
if you have a gram positive cocci in clusters, what should you suspect
staphylococcus
if you have a gram negative rod, what should you suspect
enterobacteriacea
if you have gram positive large cells, what should you suspect
yeast
if you have gram positive cocci in chains, what should you suspect
streptococci
if you have gram positive rods in palisading form, what should you suspect
corynebacterium
if you have gram negative cocci in pairs, what should you suspect
neisseria
if you have large gram positive rods, what should you suspect
bacillus or clostridium
what are the four criteria for a systemic inflammatory response syndrome (SIRS) diagnosis
fever (between 36 and 38 C)
elevated heart rate (over 90 beats/min)
elevated respiratory rate (over 30 breaths/min)
elevated white blood cell count (over 12,000)
what are the criteria important for a sepsis diagnosis
you must have all four criteria of SIRS as well as a documented or suspected infection
may also have elevations in procalcitonin, C-reative protein, hyperglycemia, and altered mental status
what are the criteria important for a severe sepsis diagnosis
SIRS along with organ dysfunction marked by:
acute oliguria (decreased urine output)
increase in creatinine
hepatic dysfunction
paralytic ileus
what are the criteria important for a septic shock diagnosis
SIRS, organ dysfunction, and hypotension refractory to fluid resuscitation or hypercalacemia
what are some characteristics of strep. pneumoniae
can cause sepsis
found on the mucosal surfaces of upper respiratory tract
gram positive
arranged in pairs
capsule
grows on blood agar - anaerobic surrounded by alpha-hemolysis
what are some characteristics of staph. aureus
can cause sepsis
found in nose and skin
gram positive
form in clusters
anaerobic, catalase positive
cause toxic shock syndrome
which organism is known to cause toxic shock syndrome (TSS)
staph. aureus
what are some characteristics of listeria monocytogenes
can cause sepsis
gram positive
rod shaped
anaerobic, beta hemolytic
has umbrella motility
can affect pregnant and immunocompromised patients
what are some characteristics of strep. agalactiae
can cause sepsis
gram positive
pairs of chains
anaerobic, beta-hemolytic on blood agar
CAMP positive, catalase negative
most commonly affects neonates
what are some characteristics of step. pyogenes
can cause sepsis
gram positive
chains and large colonies
aerobic, beta-hemolytic, catalase negative, PYR positive on blood agar
can cause scarlet fever and impetigo
what are some characteristics of enterococcus
can cause sepsis
gram positive - cocci in pairs or short chains
PYR positive
what are some characteristics of neisseria meningitis
can cause sepsis
gram negative
encapsulated
diplococci - kidney bean shaped
needs blood for growth
oxidase and catalase positive
what are some characteristics of clostridium perfringes
can cause sepsis
anaerobic
encapsulated
rod shaped, pleomorphic cells in pairs or short chains
catalase and SOD negative
double zones of hemolysis (target)
can cause food poisoning
in which organism would you see double zone of hemolysis (target)
clostridium perfringes
what are some characteristics of bacteroides
can cause sepsis
gram negative
found in the intestinal tract of humans
important factor in abscess formation
what are some characteristics of candida
can cause sepsis
encapsulated
cells much bigger than normal gram positive cocci
what is the most common organisms to cause disease in humans
Candida albicans
what are some characteristics of cryptococcus neoformans
can cause spesis
spherical yeast that has a GXM capsule
india ink and urea positive
growth on bird seed agar is black
can cause respiratory and cutaneous infections most commonly
bird seed agar is most commonly used to isolate which organism
cryptococcus neoformans
