abscess aspirate specimen analysis final
Post on 18-Feb-2017
44 Views
Preview:
TRANSCRIPT
SPECIMEN ANALYSIS:ABSCESS ASPIRATEAnneka Pierzga and Yackima Saura-WelchJune 16th, 2016MLT 2010 Clinical Microbiology (Professor Tiffany Gill) – College of Southern Maryland
THE SPECIEMN What is an abscess?
Accumulation of purulent material in the dermis or subcutaneous tissue
Appears as a swollen, red, tender and fluctuant mass Often diagnosed based on history and physical
exam, although studies suggest that soft-tissue ultrasonography may enhance accuracy of abscess detection, especially in cases of deeper or questionably appearing abscesses
Culture of needle-aspirated material useful for isolation of causative pathogens
SPECIMEN COLLECTION1. Cleanse site with sterile saline
or 70% alcohol2. Aspirate area containing
purulent material or fluid by needle and syringe (may need to irrigate with a small volume of non-bacteriostatic sterile saline)
3. Expel aspirated material in to sterile screw top tube
4. For anaerobic culture: Samples should be placed into oxygen free environment using anaerobic transport media
SPECIMEN COLLECTION
SPECIMEN COLLECTION
SPECIMEN TRANSPORT
SPECIMEN TRANSPORT “BD Port-A-Cul™ tubes, jars and vials contain a reduced transport
medium and are intended to maintain the viability of anaerobic, facultative and aerobic microorganisms during transport from the patient to the laboratory. Sterile packages are for collection of specimens in clean areas; e.g., surgical suites.”
PRIMARY SET-UP
PRIMARY SET-UP Direct examination of a Gram Stained slide
Determine the staining and morphological characteristics of pathogens to direct physician’s initial treatment plan
Inoculation of media Blood Agar Plate Chocolate Agar Plate MacConkey Agar Plate CNA Anaerobic (Columbia Agar with Colistin and Nalidixic
Acid) BBA (Brucella Blood Agar) LKV (Laked Blood Agar with Kanaycin and Vancomycin) BBE (Bacteroides Bile Esculin Agar)
CAUSES OF ABSCESSES
MAJOR OFFENDERS The leading cause of subcutaneous
abscesses in otherwise healthy individuals is…
Staphylococcus aureus Methicillin-Resistant Staphylococcus
aureus has been found to be the most common cause of abscesses in patients presenting to the emergency department in the US, followed by methicillin-susceptible S. aureus and beta-hemolytic streptococci
About Staphyloccos aureus:• Virulence factors• Colony morphology• Hemolysis• Environmental conditions• In vitro contamination• Common normal flora• Differential media• Confirmatory testing• Antibiotic susceptibility testing
Staphyloccos aureus Gram-positive cocci in grape-like clusters
Found as part of the normal flora of the anterior nares, nasopharynx, perineal area, skin, and mucosa; may be introduced to sterile sites by traumatic introduction
May also be spread from person to person by direct contact
VIRULENCE FACTORS
Polysaccharide capsule inhibits phagocytosis and helps with colonizationCatalase helps resist digestion by leukocytesPenicillinase provides resistance to penicillin-related antibioticsCoagulase enables the bacteria to hide within a clot, thereby escaping the complement system
S. aureus COLONIES
S. Aureus colonies typically appear to cream in color but occasionally have a yellow pigment.
The golden pigmentation (staphyloxanthin) has been reported to be a virulence factor protecting the pathogen against oxidants produced by the immune system
To compare in size and color S. epidermidis appears white.
Medium to large (0.5-1.5 μm); smooth, entire, slightly raised, low convex, opaque; most colonies pigmented creamy yellow; most colonies beta-hemolytic
HEMOLYSIS
Beta-hemolysis (β-hemolysis), sometimes called complete hemolysis, is a complete lysis of red cells in the media around and under the colonies: the area appears lightened (yellow) and transparent. .
ENVIRONMENTAL CONDITIONS & INCUBATION PERIOD
Grows best aerobically but are facultative anaerobic.
24 hours of incubation at 37°C
IN-VITRO CONTAMINATION
Meaning: When something foreign and non-sterile has made contact with the plate during inoculation.
Can occur by Not cleaning collection site
appropriately Not streaking plate under
the hood Opening the lid and
breathing/allowing any micro-contaminant to enter.
Not using sterile inoculating loop
The arrows indicate fungal contamination of the specimen
NORMAL FLORASince many abscesses are located beneath the skin, it is not uncommon to have normal skin flora in the sample.Coagulase negative Staphylococcus species and Enterococcus species are considered normal skin flora
DIFFERENTIAL/SELECTIVE MEDIA
Phenylethyl alcohol agar (PEA) Mannitol Salt Agar (MSA) has a 7.5%
concentration of salt and S. aureus can ferment mannitol
Columbia colistin-nalidixic acid (CNA) agar Chromogenic media DNase or thermostable-endonuclease test.
CONFIRMATORY TEST
• Gram - positive cocci
in grapelike clusters• Catalase - positive• Coagulase - positive
SUSCEPTIBILITY TESTINGIF SUSCEPTIBLE: ampicillin/sulbactam amoxicillin/clavulanate oxacillin nafcillin cefazolin ceftriaxone Macrolides ClindamycinALTERNATIVES: Trimethoprim-Sulfomethoxazole(TMP-
SMX) vancomycinMRSA: vancomycin teicoplanin linezolid quinupristin/dalfopristin TMP-SMX rifampicin
Resistance to 0.04 U of bacitracin (Taxo A disk) and furazolidone
REFERENCESBacteria in Photos. (2016). Beta hemolysis of Staphylococcus aureus. Growth characteristics of staph aureus on blood agar. Retrieved from http://www.bacteriainphotos.com/beta_hemolysis_on_agar.htmlBD (Becton, D. a. C. (2016). Diagnostic Systems: Port-A-Cul™ Tube (for Aerobic and Anaerobic Cultures). Retrieved from http://www.bd.com/ds/productCenter/221606.aspCardiovascular and Interventional Radiological Society of Europe. (2016). Aspiration.Microbiology in Pictures. (2016). Staphylococcus aureus colony morphology and microscopic appearance, basic characterisic and tests or identiication of S. aureus bacteria. Retrieved from http://www.microbiologyinpictures.com/staphylococcus%20aureus.htmlSankaqm5 (Producer). (2012, 6/11/2016). Large Abscess Cavity Pus Aspiration With Anti Gravity Technique Retrieved from https://www.youtube.com/watch?v=xP1-ccR4O2wSinger, A. J., & Talan, D. A. (2014). Management of Skin Abscesses in the Era of Methicillin-Resistant Staphylococcus aureus. The New England Journal of Medicine, 370(11), 1039-1047. Talan, D. A., Krishnadasan, A., Gorwitz, R. J., Fosheim, G. E., Limbago, B., Albrecht, V., & Moran, G. J. (2011). Comparison of Staphylococcus aureus From Skin and Soft-Tissue Infections in US Emergency Department Patients, 2004 and 2008. Clinical Infectious Disease, 53(2). The University of Texas Medical Branch. (2016). Specimen Collection: Acceptable Specimens for Bacteriologic Analysis of Wounds. Retrieved from https://www.utmb.edu/lsg/Pages/SpecimenCollection/SpecColWounds.aspxTille, P. M. (2014). Bailey and Scott's Diagnostic Microbiology (13 ed.): Elsevier.
top related