Mod 2 Specimen Collection Flashcards
What type of swab is used to collect specimen for most organisms
Polyester tipped swab on a plastic shaft
Swab that should be avoided for collection of viral cultures
Calcium alginate. Inactivates HSV
True or false. Specimens for recovery of bacteria should ideally be collected after microbial therapy has started.
False. Before
_______ may be toxic to N. gonorrheae
Cotton swab
______ shafts should be avoided and may be toxic to C. trachomatis
Wooden shaft swab
True or false. Swabs are optimal for detection of anaerobes, mycobacteria or fungi
False.(NOT) optimal
Is always superior to a swab specimen for recovery of pathogenic organisms
Tissue sample or fluid aspirate
Proper Specimen collection includes:
Specimen obtained at site of infection Minimal contamination Collected in sterile container (except stool) Labeled with name and identification # Source of specimen Date and time collected
Specimen transport.
Specimen should be placed in:
Biohazard bags
Specimen transport.
If a delay happens specimens for detection of C. trachomatis or viruses should be _______ to prevent overgrowth of normal flora
Refrigerated
Specimen transport.
If a delay happens specimens for detection of N. gonorrheae should be held at __________
Room temperature. (Refrigeration adversely affects recovery of potential pathogens)
Universal precaution:
Should be worn at all times
Gloves and lab coat
Universal precaution:
Must be worn when there is risk of splashing droplet formation
Gloves + lab coat
Mask, goggles,gowns/apron
True or false. Mycobacteria or fungi should be opened in a biological safety cabinet?
True. To prevent contamination of cell cultures
Essential in identifying bacteria responsible for bacteremia, sepsis, infections of prosthetic valves etc.
Culture of blood
Blood should be collected for culture before anti microbial therapy when any one or a combination are present:
Fever 38 C or greater Hypothermia 36 c or lower Leucocytosis Granulocytopenia Hypotension
Germane to the detection of microorganisms in the blood
Technique for specimen collection
Phlebotomy
True or false. The optimal time to draw blood for cultures when bacteremia or fungemia is suspected is just after a chill?
False. Before chills
However because it is not predictable, blood cultures are collected after the onset of fever and chills
True or false. In adults with bacteremia, the number of CFU (colony forming units) per ml is frequently low at (20-30 ml per culture set) compared to infants and children where concentration is higher with (1-5 ml of blood per culture)?
True
Nature of bacteremia:
Manipulation of a focus of infection (abscess, furuncle, cellulitis)
Surgical procedures
Localized infections like pneumonia
Transient Bacteremia
Nature of bacteremia:
Undrained abscess
Intermittent bacteremia
Nature of bacteremia:
Hallmark of intravascular infection
Continuous bacteremia
Manual blood cultures:
Consist of broth medium in a bottle to which a chamber containing agar media on a paddle is attached
Recovery of facultative bacteria and yeast
Biphasic system
Manual blood cultures:
Inhibit coagulation and the complement cascade, lyse blood cells and provide a cushion for microorganism during centrifugation
Lysis centrifugation blood culture system
Automated blood culture systems:
Enhances recovery of fungi and recovery of bacteria from pts receiving anti microbial agents
Color changes are monitored every 10 minutes ( change in color from green to yellow)
Colorimetric detection of Co2
Automated blood culture systems:
Computer generates growth curves and data are analyzed according to growth algorithms.
Fluorescent technology
Detection of positive cultures:
Detected within 12-36 hrs of incubation
Aerobic organisms
Detection of positive cultures:
Identification and susceptibility results 24-48 hours after gram staining
Aerobic organisms
Detection of positive cultures:
Not detected for 48-72 hrs and identification is not available for 3-4 days after that
Anaerobic organisms
Detection of positive cultures:
Not detected until 3-5 days
HACEK group
Haemophilus Actinobacillus Cardiobacterium Eikenella Kingella
Detection of viruses like HIV, HCV and HBV to antiviral therapy using:
Quantitative PCR
Detection of parasites:
Simplest technique
Diagnosis of trypanosomiasis or filariasis
Direct mount
Detection of parasites:
Standard preparation for determining species of plasmodium, babesia, trypanosoma and microfilaria
Thin smear
Detection of parasites:
Detects all parasites + minimum lab work up for their diagnosis
Giemsa stain, allowed to dry for dehemoglobinization
Thick smears
It is collected to diagnose meningitis
CSF
Agents most commonly responsible for meningitis
Enteroviruses
CSF is usually obtained by_______ or is aspirated from the _______ or collected from a ______.
Lumbar spinal puncture
Ventricles
Shunt
Test performed on fluid (CSF):
Tube 1: protein and glucose
Tube 2: prep smears to stain with gram stain for culture
Tube 3: cell counts
Tube 4: special tests (cryptococcal antigen)
Diagnosis of neurosyphillis based on findings:
Pleocytosis
Elevated protein concentration
Positive VDRL
Used most often for diagnosis if viral infections of the CNS
Nucleic acid amplification tests
Cultures of free living amoebas from CSF are done on _______ plates covered with a suspension of E. Coli
Non nutrient agar plates
Fluid is collected from the pericardial, thoracic, or peritoneal cavity or from joint spaces by:
Aspirating with a needle and syringe
Most common causes of infectious pericarditis
Enteroviruses ( Cox viruses A and B)
The fluid collected in a hydatid cysts specimen is usually:
Clear and contains hydatid sand
True or false. Surgeon must obtain an amount of material that is adequate for both histopathologic and microbiological examination of tissues.
True
Tissue obtained surgically should be obtained into a:
Sterile, wide mouthed, screw capped container
