Identification of Infectious Diseases Flashcards
what are the most commonly reported health conditions?
-hypertension
-arthritis
-heart disease
-cancer
-diabetes
what is the difference between malnutrition and undernutrition?
malnutrition: imbalance of nutrients and stores compared to requirements.
undernutriention: chronic inadequate intake of nutrients which causes severe weight loss
what are some considerations before introducing a new antimicrobial?
-renal and hepatic function
-infection site
-administration route
-mode of excretion of the antimicrobial
-potential toxicity of the agent
-allergy history
interpreting and evaluating lab testing is improtant for what?
-determining the diagnosis of infection
-assessing the stage of infection
-evaluating HAIs
define accuracy
proximity of the result to the true value described by sensitivity and specificity
define sensitivity
the ability of a test to detect all true cases (the absence of false negative results)
SNOUT: when negative rules a disease OUT
define specificity
the ability of a test to correctly identify a negative result when the disease is absent or the absence of false-positive results
define precision
how consistent the results are when a sample is tested repeatedly
define susceptibility
how successful an organism is to be treated by an antimicrobial
what do diagnostic tests detect?
-antigens in products that result from an infectious agent
-ab immunological response (antibody) to the infecting agent
-the presence of an agent through nucleic acid hybridization and amplification techniques
what are some common lab tests done in LTC facilities?
-urinalysis
-WBC
-NAAT/PCR
-antibody detection
-antigen detection
when is an AFB stain used?
to identify bacteria with a waxy material in their cell wall (mycobacterium)
what are cultures used to grow?
yeast and abcteria
what can a culture yield?
- polymicrobial growth: more than one type of bacteria cultivated in culture
- pure culture: single bacterial strain cultivated in culture
- no growth: no bacteria recovered from clinical specimen
when clinically significant the growth on the cultures may be:
-quantified
-semi quantified
-non quantitative
antibodys (or immunoglobulins) are produced against a foreign antigen by what?
B lymphocytes
once produced, where do antibodies circulate?
in blood, secretions, or lymphatic fluid
how can antibody detection results be reported?
-qualitatively: positive or negative (antibodys present or not)
-quantitatively: titers (volume of antibodys)
how does antibody testing work?
it is a indirect method of identifying infection by assessment of the host response (antibody production) to the bacteria or virus
what are antigens?
proteins on the outside of the virus or bacteria that stimulate the human immune system to produce antibodies
when are antigens tests helpful?
-early diagnosis (when cultures are not yet positive or possible)
-methods are designed to detect the entire or part of the antigen
true or false. urinarlysis is frequently done to assess general health
true
what is tested in basic urinarilsis?
-color and clarity, presence of proteins, glucose, ketones, blood, nitrities, and leukocyte esterase
-RBC, WBC, casts, crystals, bacteria or yeast
what are two types of WBC tests used for diagnosing infections?
-counting total number of WBC per one cuber millimeter of blood
-leukocytosis (increased WBC in response to bacteria)
define asymptomatic bacteriuria
urine is colonized and always grows bacteria even without symptoms
the recovery of how many species in urine generally indicates contamination through faulty collection or delay in transport tot he facility?
3 or more
how much poop gets collected?
a small amount the size of a loonie or until fluid line
specimens for c.diff testing must be liquid stool type what?
6 or 7 (takes the shape of the container)
which areas can you swab for MRSA>
anterior nares, perianal area, skin lesions, wound, incisions, ulcers and exit sites of indwelling devices
Which areas can you swab for VRE?
stool or rectal/swab from colostomy sites
Where would you swab for group A strep?
throat swab
how would you collect a wound swab?
-clean wound bed with saline to avoid contamination of the culture by surface organisms
-do not swab exudate or pus
-test the wound base
what swab would you do for pertussis
whooping cough
when should an NPS be collected?
as early as possible after symptom onset
what are some transportation guidelines for specimens?
-all specimens must be transported preferably within 2 hours of collection
-transport in a container designed to ensure survival of suspected agents
-materials for transport must be labelled properly, packaged, and protected during transport
Some sample should not be refigerated as they may contain microorganisms sensitive to extreme temperatures. What are some examples of samples that should not be refigerated?
-spinal fluid
-genital
-eye
-internal ear specimens
Which has no nucleus, Prokaryotic or eukaryotic
prokaryotic
define bacteria
free living, single-celled organisms that multiply through chromosonal replication and cellular division
what are some components of gram negative bacteria?
-thin pepridogylcan layer in cell wall
-lipopolysaccharide membrane
-produce endotoxins
-stained red/pink by gram stain
-more resistant to antibiotics
what are some components of gram positive bacteria?
=thick peptidoglycan layer in cell wall
-no lipopolysacchride membrane
-produce exotoxins
-stained purple by gram stain
-more susceptible to antibiotics
how can bacteria be organized?
-clusters
-chains
-pairs
what are some spirilla gram negative bacteria?
campylobacter spp
helicobacter pylori
what is a cocci gram negative bacteria?
Nisseria meningitidis
what are some gram negative bacilli?
legionella
pseudomonas
E coli
enterobacteriaxeae
salmonella
klebsiella
acinetobacter
proteus
enterobacter
serratai
what are some gram positive bacilli?
clostridium
bacillus
listeria
what are some gram positive bacteria
-enterococci: appears in chains and pairs (may be VRE)
-staphylococci: appears in clusters (MRSA)
-streptococci: appears in chains (GAS)
define flora
microbes that normally live in and on the body without causing infections or disease
what are the 2 types of flora?
- transient: colonize skin and mucosa temporarily, without invading tissues, when humans come into contact with the environment containing these organisms.
- Resident: always present on the skin and body
true or false. Flora that are commensal in a certain area of the body may be pathogenic in another area
true
which viruses are easier to kill enveloped or non-enveloped?
enveloped
immunocomprimised people are most often infected by what fungi?
candida albicans
Define parasite
an organism that lives on or within another organism and obtains an advantage at the hosts expense
Which parasites are important in LTC?
-parasites that cause GI (undercooked or contamianted food)
-skin infections (louse, bed bugs)
what are 5 principles of pathogenicity?
-virulence
-infectivity
-pathogenicity
-duration of exposure (length of time a person is exposed to an orgaism)
-size of inoculum (the number of organisms need to cause disease)
define virulence
the ability to invade and create a disease in a host
define infectivity
the ability to invade, survive in, and multiply in a host
define pathogenicity
the ability of a pathogen to cause disease
what are characteristics of innate immunity?
-chemical barriers
-physical barriers
-cellular defences
what are the types of adaptive immunity?
-active (natural, vaccination)
passive (maternal, artifical)
what are the properties of immunoglobulins?
IgA: late occuring in an immune response and longest lived
IgM: early immune recognition and response; first reacting immunoglobulin
IgA: prevneting viral infections of the respiratory tract and intestinal mucosa
IgE: allergy-inducing immunoglobulin
IgD: function in later immune response
what are some risk factors for developing bacteriuria and a UTI?
-age related physiological changes to the GU tract
-neurogenic bladder (MS, PD, Diabetes)
-urinary catheters
define CAUTI
UTI where an indwelling urinary catheter (foley) is inserted through the urethra, has been placed in >2 days and the residents develops S&S of a UTI
what is the most common organism isolated from UTIs?
e. coli
what are some appropriate uses for urinary catheters?
-acute urinary retention or bladder obstruction
-critically ill with need for input and output monitoring
-assist in sacral or perineal wound healing in an incontinent resident
-prolonged immobilization
-end of life comfort
what are some inappropriate uses for urinary catheters?
-convenience
-alternative strategies are not utilized
-specimen collection for residents who can void
-catheter is not removed when no longer necessary
insert catheters with ___ technique and ____ supplies
aseptic; sterile
true or false. when a CAUTI is suspected, remove the other catheter before obtaining a specimen to prevent contamination by biofilm
true
what is pneumonia?
inflammatory process of the lung parenchyma caused by a microbial agent
what agents can cause pneumonia?
-streptococcus pneumoniiaeae (pneumonococcus) which is a vaccine preventbale disease
-RSV
-Influenza
Influenza ___ viruses are the only Influenza viruses known to cause flu pandemics and most serious illness
A
why is the primary method for preventing Influenza and complications?
vaccination
what are some pneumonia prevention strategies?
-Flu and pneumonococcal vaccinations
-standard precautions
-prevention of oral and respiratory infections
-respiratory therapy equipment maintenance (cleaning CPAP devices on schedule, change humidifer water)
what is Norwegian scabies?
aka crusted scabies
a severe form that generally occurs in the immunocomprimsed and may produce less itching
what is scabies?
-caused by a parasitic mite
-causes pruritic skin lesion on the hands, webs of finger, wrists knees feet, armpits, butt and waist
-itching is related to allergic reaction
what are the modes of transmission of diarrheal illness?
fecal-oral
foodborne
person to person
what are some risk factors for c. diff?
antibiotic expsure, PPI, GI surgery, IBD, exposure to healthcare, chronic disease, immunosupression, age over 65 years
what is pseudomembranous colitis?
presence of punctate to confluent yellow, white, or gray plaques on the colon surfaceq
CDI is a _____ that produces _____ toxins
spore forming bacillus; 2 toxins (A and B). causes diarrhea and colitis in susceptible patients
how can CDI be diagnosed?
-stool culture: gold standard for sensitivity but TAT is 7 days
-NAAT: detects c diff toxin, increaaed sens and spef, short tat, costly and should only be used for symptomatic patients
-colon endoscopy: used to detect PMC
what is antimicrobial stewardship for c diff?
restrict clindamycin use
how can c diff be cleaned?
1:10 dilution of sodium hypocholorite
vaccination is available for which hepatitis strains?
A and B
which hep strains are transmitted through blood glucose testing equipment and unsafe injection rpactices?
B and C
for can Hep B and C be prevented?
-safe injection
-SP
-clean and disinfect blood glucose monitors between uses when shared
-HBV vaccination for hemodialysis residents and those with renal disease that may result in hemodialysis
-screening for hemodialysis residents
antimicrobial resistance is defined as
the inability to inhibit or kill the organism with clinically achieveable antimicrobial concentrations
what can cause antimicrobial resistance?
-natural (innate)
-acquire (genetic change)
-inadequate treatment 9duration or strength)
-overuse/misuse of AB
what are 3 outcomes of antimicrobial susceptibility testing.
susceptible: inhibits bacteria
intermediate: minimal inhibition
resistant: does not inhibit bacteria
what are some MDRO prevention and control methods?
-administrative support
-staff education
-judicious use of abs
-surveillance
-contact precautions when infected
-enhanced barrier precautions for MDRO colonization
-environmental measures
-decolonization
signs are ___; symptoms are ___
objective; subjective
what characteristics determine virulence?
-favored site of invasion
-disease induction
-avoidance of host resistance
-inital element: ability to survive in environment
-second element: mechanism of transmission to a new host
what is an exotoxin?
proteins produced in pathogenic bacteria as part of their growtj and metanolism. exotoxins are released in the surrounding medium following lysis
what is an endotoxin?
lipid portions of lipopolysaccrides that are part of the outer membrane of the cell wall of gram negative bacteria. liberated when bacteria die and cell wall breaks apart.
are vaccines available for endo or exotoxins? which is more toxic?
exotoxins for both
what are components of the cell mediated immune system
induced
mediated
regulated by T lymphocutes
mononuclear phagocytes
what are components of the antibody mediated humoral immune system?
CD4, CD8 (cytotoxic and suppressive) and B cells
gain the ability to recognize virus infected cells and kills them
what produces antibodies?
B lymphocytes
the most immediate SSI is caused by what bacteria?
strep pyogenes
what bacterial strcuture faciltitates bacteria implanting on plastc devices?
strep pyogenes
NHSN classification of immunocomprimsied includes what
- those with neutropenia defined as absolute neutrophil count or TWBC <500mm3
- those with keujemia, lymphona, or HIV with CD4 count <200
- those who have underhone splectomy
- history of solid organ or stem cell transplant
- cytotoxic chemotherapy
- rhose on enteral or parenteral administered steroilds daily for >14 days on the date of event
what are the most important portals of entry for opportunistic organisms?
-skin
-oropharynx
-lungs
-GI tract
which opportunistic infections are associated with breaks in skin?
staph, strep, corynebacterium, malassezia