Chap 36-BOOK (Part 2) Flashcards
One of the most important cultures for rapid, accurate results.
Blood culture
To cleanse the skin we must use
70% to 95% ethanol or isopropyl followed by 2% tincture of iodine or chlorhexidine
For patients who have IV lines through which they are getting fluids and/or medications, blood must be drawn
Below the line because blood drawn above the line will be diluted with the fluid being transfused
The optimal ratio of blood to culture
1 : 5 to 1 : 10
In cases in which a 1 : 5 dilution cannot be achieved, this can be added to the bottle
0.025% to 0.050% of SPS
The ratio of blood to broth
1 : 5 to 1 : 10
Organisms are immediately cleared from the peripheral system by the reticuloendothelial system.
Transient bacteremia
Recommended that blood culture specimens be collected before an anticipated temperature rise to ensure maximum recovery.
Intermittent bacteremia
Constantly released into the bloodstream and therefore are likely to be isolated whenever the blood culture specimen is taken
Continuous bacteremia
Standard recommended procedure for blood cultures
Inoculation of separate aerobic and anaerobic bottles
he typical aerobic culture bottle contains media that is nutritionally enriched, such as
Soybean casein digest broth, peptone broth, tryptic or trypticase soy broth, brain-heart infusion, Brucella broth, or Columbia broth base
May be added to permit the growth of certain thiol-requiring organ-sms, and the media may be prereduced to decrease the oxidation- reduction potential to help support the growth of anaerobes.
0.5% cysteine
a resin that nonspecifically absorbs any antimicrobial agent present in the patient’s blood,
Antimicrobial removal device (ARD)
SPS inhibits the growth of certain organisms, notably
Peptostreptococcus anaerobius, N. gonor- rhoeae, N. meningitidis, and Gardnerella vaginalis
Is a structural relative of SPS that is less effective in neutralizing serum bactericidal activity and is inhibitory to Klebsiella pneumoniae.
Sodium amylosulfate (SAS)
An anticoagulant, is inhibitory to some gram-positive cocci.
Sodium citrate (0.5% to 1.0%)
Sometimes used as an osmotic stabilizer.
Sucrose (10% to 30%)
blood culture bottles are typically incubated at
35° C ± 2° C for 5 days
was designed from the original biphasic (solid agar and broth combination) blood culture medium called the
Casteneda culture bottle
Most organisms will grow within
48 hours of inoculation
Manual blood culture system in which blood is inoculated into a bottle containing a liquid medium that will support the growth of aerobes, anaerobes, and microaerophiles
Oxoid Signal system
Provide optimal recovery of unusual fastidious bacteria such as Bartonella, yeasts, and dimorphic fungi mycobacteria
Lysis centrifugation method
These are noninvasive, continuous- monitoring blood culture instruments that use fluorescence to detect CO2
Bactec 9000 series and BD FX
it detects the consumption or production of multiple gases (CO2, H2, and O2) by organisms growing in the culture medium.
VersaTREK
Fully automated, nonradiomet- ric blood culture system, the BacT/ALERT 3D System, consists of aerobic and anaerobic bottles with pH-sensitive membranes placed in the bottom of the bottles.
BacT/ALERT 3D System
causative agent of tularemia, is best recovered from a liquid blood culture medium to which L-cysteine and glucose have been
added.
F. tularensis
Best recovered early in
the disease before onset of symptoms. Uses Fletcher’s media
Leptospira spp.
Conventional, manual blood culture medium (Ruiz Castañeda) should be held for up to 6 weeks at 35° C ± 2° C
Brucella
Adequately recovered using standard broth culture bottles because of the vitamin B6 present in human blood
Abiotrophia and Granulicatella
performed with a confluent growth of the test organism on a blood agar plate.
staphylococci streak test
subcultured onto selective media or enriched media such as CHOC and incubated in a microaerophilic environment at 42°C for 48 hours
Camplobacter spp. (C. jejuni)
subcultured onto selective media or enriched media such as CHOC and incubated in a microaerophilic environment at 42°C for 48 hours
Camplobacter spp. (C. jejuni)
most common fastidious bacterium reported in the literature as causing endocarditis.
Coxiella burnetii
best isolated using lysis centrifugation and plating the concentrated blood onto freshly prepared media containing 5% horse or rabbit blood
Bartonella spp.
known causes of endocarditis and will grow in blood culture bottles within 5 days. Extended incubation
HACEK
Media in the bottles contains a lysing agent and enrichment (Middlebrook-based) designed for long incubation periods, up to 6 weeks
Mycobacterium spp.
The presence of fungi in the blood is termed
Fungemia
presence of viruses in the blood
Viremia
Has been demonstrated to be occasionally contaminated with Burkholderia cepacia and Enterobacter spp.
Benzalkonium chloride
Contamination of certain iodine solutions, such as povidone-iodine, with
B. cepacia has also been reported. Con- tamination with Serratia marcescens and Moraxella spp
This test can be used to determine
whether gram-positive cocci in clusters growing in a blood culture are S. aureus (coagulase-positive) or CoNS.
Direct Tube Coagulase.
Uses an oligonucleotide or peptide nucleic acid probe with a fluorescent label. Although this is a molecular method, there is no amplification of
Fluorescence in situ Hybridization
Methods using nucleic acid amplification, such as the polymerase chain reaction assay, which can identify microorganisms growing in a blood culture, are increasingly available.
Nucleic Acid Amplification Methods
Most common cause of admissions and death in intensive care units and rates are increasing.
Sepsis
considered the “gold standard”, they are positive in only about one-third of sepsis cases and generally require 3 to 5 days for a positive result
Blood culture
classic indicators of sepsis
elevated white blood cell count, fever, elevated C-reactive protein, and hypotension,
defined as an objectively measured characteristic that indicates a normal biologic or pathogenic process, or pharmacologic response to therapy
Biomarker
defined as an objectively measured characteristic that indicates a normal biologic or pathogenic process, or pharmacologic response to therapy
Biomarker
a peptide released in response to proinflammatory stimuli, is regarded as a potential biomarker for sepsis.
Procalcitonin
Has been found to be helpful in indicating severe sepsis, particularly when used with C-reactive protein or procal- citonin levels
serum lactate (lactic acid)
mainstay of treatment of bacteremia
Antimicrobial agents
Are frequently used for initial empiric therapy, and a combination of agents may be used to ensure coverage of several possible pathogens.
Broad-spectrum antimicrobial agents
Is a fundamental method for management of the septic patient.
Resuscitation with IV fluids to maintain tissue perfusion
shown in clinical trials to decrease mortality in patients with septic shock
drotrecogin alfa, also known as activated protein C
Drotrecogin alfa inhibits factors
Va and VIIIa
potent antiinflammatory action; interest in the treatment of sepsis
glucocorticoids
Aimed at blocking the action of tumor necrosis factor and other cytokine mediators of sepsis have been studied in the treatment of sepsis.
Anticytokine Therapies
