Aerobic and facultatively anaerobic Gram (+) Catalase (+) Spore-forming bacilli B. anthracis characteristics non-motile “bamboo rod” appearance Produces endospores Appearance in 5% SBA: Medusa head Ground glass appearance Beaten egg whites In MHA: String of Pearls Virulence factors Protective Antigen – facilitates transport of two other protein into the cell. Edema factor (adenylate cyclase) – …
Gram (+) cocci In pairs or chains Aerotolerant anaerobes Some are capnophilic Characteristics COLONY Usually small and transparent CATEGORIES OF NECROTIZING FASCIITIS Type Description 1 Polymicrobial infection (aerobic & anaerobic) 2 Consist of Group A Streptococci 3 Clostridial myonecrosis Saltwater Necrotizing Fasciitis Caused by Vibrio spp Organism Lancefield Smith and Brown’s S. pyogenes A Beta …
Gram (+) cocci Facultatively anaerobes (except for S. saccharolyticus – OBLIGATE ANAEROBE) In tetrads or in clusters Catalase (+) Oxidase (+) Non-motile Grows in 7.5 – 10% NaCl Characteristics COLONY Produced after 18-24 hrs. Medium-sized (4-8 um) COLORS: Cream-colored White Rarely light gold “buttery-looking” HUMAN NARIS (NOSTRILS) – PRIMARY RESERVOIR FOR STAPHYLOCOCCI S. aureus Disease …
AST STANDARDIZATION McFarland Turbidity Standards 1% H2SO4 1.175% BaCl2 0.5 McFarland – most commonly used Growth Medium pH – 7.2 – 7.4 cation concentration blood and serum components thymidine content Testing Medium for Different Organism Organism Media Incubation Notes Enterobacteriace ae P. aeruginosa Enterococci Mueller Hinton 35°C; air 16 – 20 hrs. Staphylococi MH …
POLYMERASE CHAIN REACTION DENATURATION – 94 – 95 degree Celsius (15 – 30 secs) For dsDNA separation PRIMER ANNEALING – 45 – 65 degree Celsius (30 secs. – 2 mins.) Anneals primer to target DNA PRIMER EXTENSION – 68 – 72 degree Celsius Synthesis of new strands of DNA PCR COMPONENTS Template DNA – target …
AMERICAN TRUDEAU SOCIETY MEDIUM Egg-based Purpose – isolation of M. tuberculosis Component: Eggs – provides fatty acid Potatoes – carbon source Malachite green – inhibitor LOWENSTEIN-JENSEN MEDIUM Purpose – for cultivation of Mycobacterium spp. Component: Potato flour Egg Glycerol Asparagine – for max. production of niacin by certain Mycobacterium spp. Malachite green – inhibitor MODIFICATIONS …
ACETATE AGAR Purpose differentiate E. coli from Shigella spp. Components Acetate – carbon source Bromthymol blue – pH indicator RESULT Green – negative (didn’t utilized acetate) Blue – positive (utilized acetate) ALKALINE PEPTONE WATER Purpose for recovery of Vibro spp. And Aeromonas spp. Components 0.5 – 1.0% NaCl – to recover Vibrio spp. BACTEROIDES BILE …
PRINCIPLES OF SPECIMEN COLLECTION Major goal of microbiology laboratory – aid diagnosis of infectious disease Goal of specimen collector – maintain viability w/ minimal contamination FUNDAMENTALS Collect in acute phase of infection and before antibiotics administration (or within 2-3 days for viral infection) Correct anatomic site for collection Proper technique and supplies w/ minimal contamination …
Collection, Transport, Processing, and Staining of Specimens Read More »
