Microbiology Unit 7 Chapter 39 Sample Collection and Handling Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved.

Sample Collection Samples collected by various methods Aspiration Swabbing Imprints Specific sampling technique used depends on type of lesion and location Aseptic technique critical Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 2

Aspiration Hollow organs Bladder External lesions Pustules Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 3

Swabs Sterile swabs Samples that are to be processed immediately Least suitable method Contamination risk is high Cotton can inhibit microbial growth Oxygen trapped in fibers – anaerobes Rayon or Dacron swabs preferred If delays expected Culturette (transport media) Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 4

Specimens Must contain the organism causing the problem Normal flora and contaminants may complicate collection and results Best to use techniques that would be normally sterile and aseptic techniques Urine – cystocentesis Intact pustules Ears and fecal samples – not optimal Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 5

Guidelines for Proper Collection Complete history and sufficient clinical data to help select procedures to best isolate organisms that may be present Data labeled and complete information supplied Owner’s name Clinic name Address and phone number Species, name, age, sex, number of animals affected or dead Duration of the problem Major signs observed Tentative diagnosis Organism suspected Any treatment given Type of laboratory investigation required Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 6

Guidelines for Proper Collection (cont.) Collect specimen aseptically Collect as soon as possible after onset Multiple specimens must be kept separate to avoid cross-contamination Container labeled Especially zoonotic-suspected organism Specimens submitted in sealed, leak-proof, unbreakable container Adequate time for collection Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 7

Guidelines for Proper Collection (cont.) Dermatophytes Clean skin lesion to remove surface contamination Collect from periphery of lesion Broken hair and dry scale most likely to contain viable organisms Pluck or use toothbrush to obtain hair and skin samples New toothbrush Brush lesion for 1 to 2 minutes Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 8

Collection of Viral Specimens Viruses often present in nasal or pharyngeal secretions in early stage of URI Mucosal scrapings rather than swabbing Tongue depression Attempted isolation from blood sample may be considered in generalized catarrhal diseases Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 9

Viral Specimens Specimens selected for indirect studies Serologic Hematologic Histologic Bacteriologic Viral diseases often complicated by pathogenic bacteria – secondary infections Tissue samples – 2-inch cubes Both diseased and normal tissue Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 10

Submission of Samples Refrigerated at 4° C Decreases virus titers If delivered within 24 hours: Pack with coolant packages in a polystyrene- insulated carton If over 24 hours: Snap freeze at  70° C and ship on dry ice Except suspected parainfluenza and influenza Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 11

Submission of Samples (cont.) Small tissue pieces, fecal material, or mucus Preserved in vials filled with 50% glycol Contact reference laboratory for specifics on shipping For scanning electron microscopy A fixative – 10% buffered neutral formalin 1:1 Urine samples 5 mL sent in sterile container Chilled within 24 hours or frozen at  270ºC Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 12

Summary Samples collected quickly and do not require specialized materials or equipment Aseptic techniques Collection by swabbing, aspiration, imprint, biopsy, and other techniques Dermatophytes collected by plucking hair or skin from lesion Normal flora and contaminants may complicate sample collection and results Copyright © 2015 by Mosby, an imprint of Elsevier Inc. All rights reserved. 13