Chapter 13 Flashcards
1
Q
proper diagnosis of infectious disease requires:
A
- complete pt hx
- physical exam
- evaluate signs and symptoms
- proper selection, collection, transport, and processes of specimens
2
Q
clinical specimens
A
- collected from pts such as blood, urine, faces, and CSF
- all should be of highest possible quality
- commonly submitted to microbiology lab include blood, bone marrow, sputum, pus, skin scrapings, throat swabs
3
Q
role of HCP in submitting clinical specimens
A
- close working relationship among team to ensure proper diagnosis
- exercise extreme caution during collection and transport of specimens
- in labs al specimens are handled carefully exercising standard precautions
4
Q
high quality clinical specimens
A
- required to achieve accurate relevant results
- lab must provide written guidelines
5
Q
3 components of specimens quality
A
1) proper selection
2) proper collection
3) proper transport to the lab
6
Q
who is responsible for specimen quality
A
- the person who collects the specimen
7
Q
proper selection, collection, and transport (12)
A
- properly selected and collected
- from site where pathogen is suspected to be
- obtained before antimicrobial therapy
- collect during acute stage
- performed with care to avoid pt harm
- sufficient quantity collected
- placed or collected into sterile container
- protected from heat and cold and promptly delivered to lab
- hazardous specimens handled with higher caution
- sterile disposable container should be used
- properly able container with request slip and instructions
- collected and delivered as early as possible in the day
8
Q
blood specimens
A
- blood is usually sterile
- aseptic technique used with care to avoid contamination with indigenous skin microbiota
9
Q
bacteremia
A
presence of bacteria in bloodstream
10
Q
septicemia
A
- serious disease characterized by chills, fever, prostration, and bacteria or other toxins in bloodstream
11
Q
plasma
A
liquid portion of unclothed blood
12
Q
serum
A
liquid portion of clotted blood
13
Q
during specimens
A
- sterile in bladder but becomes contaminated by indigenous microbiota of distal urethra during voiding
- contamination reduced by using clean catch midterm urine sample
14
Q
3 parts of urine culture
A
1) colony count using calibrated loops
2) isolation and identification of pathogen
3) antimicrobial susceptibility testing
15
Q
urine colony count
A
- way of estimating number of viable bacteria
- 0.01 or 0.001 mL calibrated loop used to inoculate blood agar plate
- incubation over night at 37C
- colonies counted and number multiplies by dilution factor to determine number of colony forming units
16
Q
urine colony count formula
A
# of colony forming units = # of colonies x dilution factor - dilution factor = 100 for 0.01 ml loop or 1000 for 0.001 ml loop
17
Q
CSF specimen
A
- collected by lumbar puncture (spinal tap) into a sterile tube
- in lumbar to avoid nerve damage
- surgically aseptic technique performed by physician
- considered stat specimen in lab
18
Q
meningitis
A
- inflammation/infection of membranes that surround brain and spinal cord
- pia and dura mater
19
Q
encephalitis
A
- inflammation/infection of brain
20
Q
meningoencephalitis
A
- inflammation/infection of both brain and meninges
21
Q
sputum
A
- pus that accumulates deep within lungs of pts with pneumonia, TB, or lower respiratory tract infections
22
Q
sputum specimen
A
- often just saliva samples, which won’t provide clinically relevant info
- better specimens can be obtained by bronchial or transracial aspiration
- use extreme care if TB is suspected
23
Q
throat swabs
A
- routinely used to determine strep throat
- specific cultures necessary when neisseria gonorrhoea or corynebacterium diphtheria are suspected
24
Q
wound specimen
A
- should be an aspirate rather than a swab when possible to avoid contamination with indigenous microbiota
25
gonococci (GC) cultures
- for neisseria gonorrhoea
- N. gonorrhoea is a fastidious, microaerophilic and capnophilic bacteria
- only dragon, calcium alginate, or nontoxic cotton swabs used for GC specimens
- vaginal, cervical, urethral, throat, and rectal specimens are cultured on Thayer-marin agar and incubated in CO2 incubator
- specical transport media available and GC swabs should never be refrigerated
26
fecal specimens
- collected at lab and processed immediately to avoid a temperature drop causing pH drop which ills shigella and salmonella spp
- bacteria in faces are obligate, aerotolerant, and facultative anaerobes
- combination of microscopic exams, culture, biochemical and immunological tests may be performed to identify gram -/+ bacteria, fungi, intestinal protozoa and helminths from fecal specimens
27
pathology department
- clinical specimens are submitted to CML which s part of pathology department
- under direction of a pathologist
28
2 divisions of pathology department
- anatomical pathology
| - clinical pathology
29
anatomical pathology
- disease organs, stained tissue sections, and cytology specimens
- morgue, histopathology, cytology, cryogenics, election microscopy lab
30
clinical pathology
- several labs in addition to CML
| - clinical chemistry, hematology, immunology, blood bank
31
clinical microbiology lab
- mycology
- bacteriology
- parasitology
- mycobacteriology
- virology
- immunology
32
CML responsibilities
- assist clinicians in diagnosis and treatment of infectious diseases
33
4 day to day responsibilities in CML
1) process clinical specimens
2) isolate pathogens from specimens
3) identify pathogens
4) perform antimicrobial susceptibility testing when appropriate
34
bacteriology section
- isolate and identify bacterial species
- gather clues about a pathogen until able to identify it
- phenotypic characteristics like gram reaction, shape, motility, presence and location of spores, and various enzymes are used for identification
35
specimen processing steps
- macroscopic exam, gram stain observation, inoculation of media
- obtain pure culture
- perform tests to identify pathogen
- antimicrobial susceptibility testing
- report findings to clinician
36
mycology section
- assist in diagnosis fungal infections
| - same processing as bacteriology but include hair and nail clipping and skin scrapings
37
parasitology section
- assist in diagnosing parasitic diseases
| - identified by observing life cycle in specimens and by physical appearance
38
virology section
- assist in diagnosing viral diseases
- immunodiagnotics, cytologic/histologic exam, electron microscopy, molecular techniques, virus isolation, and cytopathic effect
39
mycobacteriology section
- TB lab
- assist in diagnosis of TB
- sputum is most common specimen types submitted
- identified using acid-fast staining procedure and combination of growth characteristics and biochemical tests
