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Bioterrorism Agents – Plague Lesson 4. Laboratory. Objectives. List appropriate specimens List tests available for diagnosis List laboratory criteria for diagnosis Describe safety procedures. Overview. Critical for first cases Collect immediately and before antibiotics
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Bioterrorism Agents – PlagueLesson 4 Laboratory
Objectives • List appropriate specimens • List tests available for diagnosis • List laboratory criteria for diagnosis • Describe safety procedures
Overview • Critical for first cases • Collect immediately and before antibiotics • Store appropriately • Presumptive diagnoses
SpecimensRespiratory • Pharyngeal swabs • Tracheal washes or aspirates • Sputum specimens • Trans-thoracic lung aspirates • Pleural fluid collection • Testing – Staining, culture, DNA amplification
SpecimensTissues • Lung tissue • Lymph node tissue • Spleen • Liver • Testing – Culture, Gram stain
SpecimensTissues (Autopsy) • Lung • Liver • Spleen • Lymph nodes • Skin lesions • Kidney • Testing – PCR (Specimens kept fresh frozen, unpreserved)
SpecimensBlood • Baseline before antibiotics • Convalescent • Minimum 14 days apart • 3 to 4 weeks after symptom onset • Two or more sequentially collected samples preferred
Specimen HandlingRespiratory, Blood • Respiratory/Sputum • Sterile screw-capped containers • Room temperature (store 2C-8C if 2-24 hrs) • Blood • Direct to lab at room temperature • Hold at ambient until incubator • Do not refrigerate
Specimen HandlingTissue • Sterile container • 1 to 2 drops normal saline • Transport at room temperature • Chill if delay Contact public health for detailed instructions
SpecimensTissue Handling • Split into non-glass containers • 4C for live recovery • -20C or -70C for rapid molecular testing • Formalin-fixed • Tests – Histopathology, HC, PCR • NOT frozen • Packaged separately from unpreserved
Laboratory TestingPneumonic Plague • Collect before initiating therapy • Sputum, blood, lymph node aspirate • Gram Stain and culture • Gram-negative coccobacillus • Bipolar (safety pin) staining • Acute and convalescent bloods for public health
Laboratory TestingPneumonic Plague • Coagulation abnormalities • Fibrin split products • DIC possible • Increased fibrin degradation products • Hypofibrinogenemia • Prolongation of PT and PTT
Laboratory Case ClassificationSuspect Definition • Clinical sx and exposure compatible AND • Small, Gram-negative and/or bipolar-staining, plump rods in singles, short chains, catalase (+) oxidase and urease (-) Lab Tests – Gram stain, differential stain, culture, catalase, oxidase urease
Laboratory Case ClassificationProbable Definition • Clinical sx and exposure compatible AND • Specimen/Isolate positive by one of: DFA, PCR, IHC • OR single PHA/HI titer of 1:10 or positive ELISA Lab Tests – DFA, DNA, IHC, Serology
Laboratory Case ClassificationConfirmed Definition • Positive DFA or DNA detection and bacteriophage lysis of recovered isolate • OR Paired sera 4-fold rise or fall by PHA/HI or ELISA Tests – Bacteriophage lysis, Serology, IHC
Review Questions - Plague Lesson 4
Plague Review QuestionLesson 4, Question 1 • Suspect pneumonic plague • Sending for labs before antibiotics Which of the following is best for organism identification?
Plague Review QuestionLesson 4, Question 1 Which of the following is best for organism identification? • Obtain initial blood specimen • Obtain more than one blood specimen • Get plasma or whole blood specimen on filter paper • A smear or isolate from affected tissues
Plague Review QuestionLesson 4, Question 1 Which of the following is best for organism identification? D. A smear or isolate from affected tissues
Plague Review QuestionLesson 4, Question 2 • Suspect pneumococcal plague patient • Sputum sample What tests would your laboratory perform?
Plague Review QuestionLesson 4, Question 2 What tests would your laboratory perform? • PCR • Gram stain and culture • IHC
Plague Review QuestionLesson 4, Question 2 What tests would your laboratory perform? B. Gram stain and culture
Plague Review QuestionLesson 4, Question 3 • Lab unable to rule out Y. pestis • Specimens sent to public health • Patient now suspect case At what point would public health rule them a confirmed case?
Plague Review QuestionLesson 4, Question 3 At what point would public health rule them a confirmed case? • Positive by DFA Staining • Positive by PCR • Isolate lysed at 22C-25C and 37C • Single PHA/HI titer <1:10
Plague Review QuestionLesson 4, Question 3 At what point would public health rule them a confirmed case? C. Isolate lysed at 22C-25C and 37C
Plague Review QuestionLesson 4, Question 4 • About to submit blood specimens • Possible Y. pestis What should you do first?
Plague Review QuestionLesson 4, Question 4 What should you do first? • Treat it as you would others • Do not refrigerate • Contact public health epidemiology • Contact public health laboratory
Plague Review QuestionLesson 4, Question 4 What should you do first? D. Contact public health laboratory