Used correctly, microbiologic cultures can identify etiologic agent(s) and
contribute key information towards a diagnosis. However, improperly collected
microbiologic cultures may identify contaminants or overgrow pathogens and lead
to erroneous diagnoses. Etiologic agents can be missed because of improper
transport medium, improper transport environment, or improper preservation
techniques.
The value of microbiologic culture depends to a considerable degree on the care
and skill with which cultures are taken, stored and shipped to the laboratory.
We offer the following guidelines to optimize these procedures: |
 |
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Samples should be collected aseptically and placed in sterile plastic bags
(e.g., Whirl-pak) or heat sterilized containers. Seal tightly. Do not use
chemically disinfected containers, or plastic gloves or sleeves.
-
Label all submissions with the location (tissue) and species of origin. The same
bacterial species may be highly significant or a meaningless contaminant,
depending on the tissue and/or species from which the sample was obtained. Also,
depending on the tissue/species of origin, different culture conditions may be
necessary to isolate and identify specific pathogens.
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If possible, specify the test(s) you want done, and the pathogens you suspect,
particularly in the case of specimens with normal bacterial flora (feces,
intestinal contents, skin, or oral mucus membranes). If we don't know what
you're looking for, we may not inoculate the proper media to find it.
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It is best to collect other samples before opening the gastrointestinal tract.
Tissue samples (lung, liver, spleen, kidney, etc.) should be 5 g or larger to
allow surface searing in the laboratory to reduce contaminants. Use screw top
containers for fecal samples. Fecal samples should not be
submitted in stoppered tubes, as fermentation will dislodge the stoppers.
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Place each sample in a separate container to prevent cross-contamination. If
the intestine is to be cultured, tie off both ends of a segment and place it in
a separate container.
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Except in the case of abortions, please separate samples that are to be examined
by different laboratory sections. If a specimen is to be examined by both the
virology and bacteriology sections, the specimen should be divided, each piece
placed in a separate container, and labeled with the source of the tissue and
the desired laboratory service.
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Fluids for culture (e.g. body cavity fluids, pericardial fluid, joint aspirates)
should be submitted in a sealed sterile tube, in as large a volume as is
available (up to ~10 ml), since the concentration of organisms may be very low
in these samples. Fluids may be submitted in blood culture bottles or Isolator
tubes (keeping in mind that Isolator tubes must be processed in the lab within
24 hrs) for highest sensitivity. Fetal fluids (thoracic or peritoneal fluids, or
heart blood) to be examined for Leptospira sp. by FA test are best submitted in
a sealed sterile tube to which 10% buffered formalin is added at a rate of 1.5
ml per 20 ml fluid. Never submit fluid in syringes, which tend
to leak in transit and contaminate packaging.
Never submit fluids or other specimens for bacteriologic culture in EDTA
(purple top) Vacutainer tubes, as EDTA is highly toxic to many
bacterial species.
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Milk samples should be submitted in screw top tubes frozen or placed on ice
packs. Less than 1 ml is required. Large volume milk samples submitted frozen
may lead to delayed analysis.
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Specimens for isolation of anaerobic pathogens require special care. Anaerobic
bacteria are very susceptible to oxygen exposure. Tissue or fluid specimens are
preferred, and if swabs are the only practical sample, the Port-a-Cul system is
preferred. Cultures for Clostridium
sp. in parenchymatous organs ordinarily provide no significant information
concerning the cause of death if the samples are taken more than one hour after
death.
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Some specimens, such as porcine nasal swabs for Bordetella
sp. isolation must be delivered to the laboratory within 12 hours of collection.
Fastidious organisms such as Campylobacter spp. require special media for
transport to the laboratory. Where there is any doubt as to what samples to
collect and how to transport them - - CALL THE LABORATORY FIRST!
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When collecting large numbers of samples (e.g. >30 milk samples for mastitis
diagnosis or fecal samples for Johne's disease diagnosis), please call the
laboratory for scheduling. This permits the laboratory to have personnel and
media available for prompt processing.
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In general, it is advised to keep specimens cold from the time they are
collected until they arrive at the laboratory. Specimens should be shipped in
insulated containers with a sufficient number of ice packs to last 48 hours.
Specimens arriving in the laboratory in a decomposed state will not be
processed, since processing and culture of these tissues lead to meaningless or
erroneous results.
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For cases where bacteremia is suspected and blood culturing is requested, blood
culture systems should be inoculated with the proper amount of blood collected
aseptically. Single bottle blood culture systems are recommended.
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Select samples judiciously! See the following list for guidelines, and call the
laboratory if questions remain.
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Different bacteriologic procedures take different times to complete; approximate
culture times are as follows:
|
Aerobic (culture and sensitivity) |
3 days |
|
Anaerobic |
7-10 days |
|
Listeria spp. |
7 days |
|
Mycology |
>2 weeks
|
|
Mycoplasma
|
2 weeks
|
Mycobacteria paratuberculosis (culture)
*Note, direct PCR is recommended for this agent. |
13 weeks
|
|
Disease
|
Fees
|
Specimen
|
Remarks & Suggested Ancillary Testing
|
| Abortion |
fee schedule |
Dam: Placenta (cotyledon best in ruminants),
vaginal swab, cervical mucus. Fetus: liver, lung kidney, stomach contents,
thoracic fluid.
|
Histopathology, Virology, Serology Histopathology, Virology
|
| Abscess |
fee schedule |
Swab |
Anaerobic
See note 9 |
| Actinobacillosis or Actinomycosis |
fee schedule |
Exudate or lesion (sulfur granule if present) |
Anaerobic
See note 9 |
| Anthrax (B. anthracis) |
fee schedule |
Blood, spleen, or lymph node |
Necropsy contraindicated |
| Arthritis |
fee schedule |
Carcass, affected joint, synovial tissue, or joint
fluid |
Mycoplasma, Anaerobic
See note 9 |
| Atrophic rhinitis (B. bronchiseptica) |
fee schedule |
Swabs, must arrive at the lab within 12 hours. |
Histopathology |
| Black leg (Clostridial myositis) |
fee schedule |
Entire carcass, Affected muscle |
Histopathology
See note 9 |
| Blood culture |
fee schedule |
Inoculated blood culture system. |
|
| Botulism |
fee schedule |
|
Call the laboratory |
| Brucellosis |
fee schedule |
See
abortion |
Serology |
|
Campylobacteriosis
Enteric:
Reproductive:
|
fee schedule |
Feces
See
abortion
|
Special transport media required |
| Caseous lymphadenitis (C. pseudotuberculosis) |
fee schedule |
Affected lymph node or swab of contents |
|
| Colibacillosis |
fee schedule |
Entire carcass, loop of duodenum, mesenteric lymph
node |
|
| Corynebacterium equi
pneumonia |
fee schedule |
See
Rhodococcus equi |
|
| Contagious equine metritis (Taylorella
equigenitalium) |
fee schedule |
Female: Cervical secretions
Male: Urethral fossa secretions |
Not offered by WADDL. Call for suggested laboratories. |
| Dermatophilosis (Dermatophilus congolensis) |
fee schedule |
Scabs, purulent exudate |
Histopathology
|
| Enteritis |
fee schedule |
Entire carcass, loop of affected intestine,
mesenteric lymph node |
Histopathology
E. coli typed by PCR |
| Enterotoxemia (Clostridium perfringens) |
fee schedule |
Intestines or intestinal contents. Must be
collected within 4 hours of death for interpretation of results. |
Histopathology
Typed by PCR |
| Erysipelas (Erysipelothrix rhusiopathia) |
fee schedule |
Entire carcass, Liver, heart, spleen, kidney,
lymph node, affected joint. |
Histopathology |
| Glasser's disease (Haemophilus
polyserositis) |
fee schedule |
Entire carcass
Unopened joint and inflamed serosa |
Deliver immediately or freeze |
| Hemophilus pneumonia |
fee schedule |
Entire carcass
Thoracic fluid, lung, nasal swab |
Histopathology, Serology |
| Hemorrhagic bowel syndrome (Lawsonia
sp.) |
fee schedule |
Non-culturable agent |
Histopathology, Serology, Molecular diagnostics |
| Johne's disease (Mycobacterium
paratuberculosis) |
fee schedule |
Entire carcass
Rectal biopsy or large intestine/ileocecal valve, regional lymph node, feces
(2-10g) |
Recommended test for fecal samples is PCR.
Histopathology, Serology |
| Leptospirosis (See
abortion) |
fee schedule |
Entire carcass
Kidney, Urine |
Serology, Darkfield examination, IHC, Molecular Diagnostics |
Listeriosis
CNS
Abortion |
fee schedule |
Entire carcass
1/2 cerebellum, pons, medulla
Fetal liver, kidney, spleen |
Histopathology |
| Malignant Edema |
fee schedule |
Entire carcass, Lesion |
See note 9, Histopathology |
| Mastitis |
fee schedule |
Milk. Use proper sample container half full or
less. Call lab before submitting large (>30) numbers of samples. |
Mycoplasma cultures by specific request only |
Mycoplasma
- Arthritis
- Mastitis
- Pneumonia
|
fee schedule |
Entire carcass
Joint fluid
Milk
Entire carcass or affected lobe(s) |
Histopathology, Culture requires special media. Deliver immediately or
freeze samples. |
| Nocardiosis |
fee schedule |
Entire carcass, Lesion |
Histopathology |
| Pasteurellosis |
fee schedule |
Entire carcass, Affected lobe |
Histopathology |
| Pneumonia |
fee schedule |
Entire carcass, Affected lobe |
Histopathology, Virology, Serology, Mycoplasma culture |
| Polyarthritis |
fee schedule |
Entire carcass, Joint fluid |
Histopathology, Deliver immediately or freeze. |
| Polyserositis |
fee schedule |
Entire carcass, Joint fluid and affected serosa |
Histopathology, Deliver immediately or freeze. |
| Rhodococcus equi
pneumonia |
fee schedule |
Affected tissue, swab, or trans-tracheal aspirate |
Histopathology
Typed by PCR |
| Salmonellosis |
fee schedule |
Entire carcass, Loop of intestine/colon, feces,
lymph nodes, spleen, and lungs |
Serogroup typing at WADDL, forwarded to NVSL for serotype determination. |
| Salmonellosis - Reptiles |
|
Fecal |
Reptiles that test negative still represent high risk for salmonella
exposure. |
| Strangles (Streptococcus equi) |
fee schedule |
Swab of exudate |
|
| Swine dysentery |
fee schedule |
Entire carcass, Colon |
Histopathology |
| Thromboembolic meningoencephalitis (Haemophilus
somnus) |
fee schedule |
Affected organs, and 1/2 brain |
Histopathology, Serology |
| Trichomoniasis |
fee schedule |
Uterine exudate, preputial scrapings. |
Diamond's medium, Do not refrigerate or ship with ice packs |
| Tuberculosis |
fee schedule |
Culture not performed at WADDL, tissues sent to
NVSL |
Histopathology |
| Tyzzer's Disease(Bacillus piliformis, now
Clostridium piliformis) |
fee schedule |
Culture not rewarding |
Histopathology, submit liver and gut in formalin |
| Ureaplasma |
fee schedule |
Vaginal swabs from
affected cows |
Must reach laboratory within 4 days |
| Vibriosis |
fee schedule |
See
Campylobacter spp. |
|