ML 228 - Clinical Microbiology II Lecture

• Collection and Handling of Specimens for Microbiological Examination:
  • describe procedures for appropriate body site sampling and proper time for collection of microbiological specimens;
  • state the appropriate collection/transport device for various patient specimens; e.g. throat culture; and
  • outline the proper procedures for handling microbiological specimens which may be a possible cause of laboratory acquired infections such as respiratory tract specimens or suspected systemic fungal infections.
• Cultivation and Isolation of Microbes from Patient Specimens:
  • state the necessary growth conditions for cultivation of pathogenic microbes;
  • list the components of primary plating media and the appropriate use of each type of media;
  • state the necessary growth conditions for cultivation of pathogenic microbes from patient specimens;
  • identify the possible bacteria which may be isolated from various types of body specimens; and
  • outline the approach to the identification of pathogens including the Gram Stain reaction, biochemical, enzyme, and agglutination tests.
• Bacterial Pathogens:
  
  The following groups of microorganisms will be examined and described according to the characteristics listed below in items a-c: Gram positive cocci, Gram negative aerobic cocci, Gram positive bacilli, Gram positive spore forming bacilli, enteric Gram negative bacilli, Gram negative coccobacilli, spirochetes and other spiral-shaped organisms and non-fermenting Gram negative bacilli.
  
  • compare and contrast the characteristics of the group of pathogenic microbes listed above in relation to cell and colony morphology, staining, and biochemical reactions;
  • describe symptoms, mode of transmission and virulence characteristics of each organism; and
  • outline methods of identification of member genera utilizing specific media, biochemical tests, and culture techniques, including both presumptive and confirmatory tests.

The preceding is applied to the following topics – Groups 1 to 9:

• Gram Negative Enteric Bacteria (Enterobacteriaceae):
  • differentiate between normal intestinal flora, a primary pathogen, and an opportunistic pathogen;
  • define the family Enterobacteriaceae on a morphological and biochemical basis and list the pathogenic members of the family using genus and species designation;
  • identify the reactive component for the individual biochemical media;
  • for each genus discussed, the student will complete the following:
    • state the organism’s microscopic morphology;
    • describe the colony morphology on selective and differential media;
    • identify the key biochemical reactions of the specific genera belonging to the Enterobacteriaceae family;
    • state the key biochemical reactions to differentiate the species within a genus; and
    • review the pathogenesis of significant enteric microorganisms.
  • describe the antigenic structure of: E. coli, Salmonella, Shigella; and
  • define the concept of serologic identification of the enteric bacilli, include antigen and location on the bacterial cell.
• Non-Fermentative Gram Negative Bacilli:
  • state the principle of the oxidative-fermentative test;
  • describe the procedures for the identification of a member of this group such as the oxidase reaction, motility, growth on MacConkey agar and flagella stain;
  • explain how OF Medium may be used to differentiate fermentative, oxidative, and non-saccharolytic organisms; and
  • identify significant species of Alcaligenes, Pseudomonas, Burkholderia, Chryseobacterium, Stenotrophomonas, Acinetobacter, and Moraxella.
• Vibrionaceae, Curved Gram Negative Bacilli, and Oxidase Positive Fermenters: Vibrio, Campylobacter, Helicobacter pylori, Aeromonas, and Plesiomonas:
  • state the significant characteristics of Vibrio cholerae including selective media (TCBS) for isolation, cell morphology, flagellar arrangement, and RBC agglutination;
  • describe the pathogenesis of cholera and how it is effectively treated;
  • list the important features of Vibrio parahaemolyticus including disease production and differentiation from V. cholerae;
  • state the isolation procedures and identifying traits of Campylobacter jejuni including complex atmospheric conditions, selective media, biochemical tests, and appearance on a direct smear;
  • describe the disease produced by C. jejuni pylori;
  • review the significant features of Helicobacter pylori including laboratory identification, pathogenesis, and treatment of peptic ulcer disease;
  • be able to differentiate Aeromonas hydrophilia and Plesiomonas shigelloides according to growth on selective media, DNase, V-P test, flagellar arrangement, and hemolysis on blood agar; and
  • state how A. hydrophilia and P. shigelloides infections are acquired.
• Gram Negative Coccobacillary Facultative Bacteria:
  Pasteurella, Francisella, Bordetella, Haemophilus, and Legionella
  • describe the major diseases produced by the genera in this group;
  • list the identifying features of the major pathogens including P. multocida, F. tularensis, Bordetella pertussis, and Legionella pneumophila;
  • characterize the significant Haemophilus species according to biochemical testing and “X” and “V” factor requirements; and
  • state the diseases produced by pathogenic Haemophilus species.
• Aerobic Gram Negative Cocci:
  • define the Neisseria on a morphological and biochemical basis;
  • list the pathogenic members of the family Neisseriaceae;
  • differentiate Neisseria gonorrhoeae from Neisseria meningitidis and Moraxella (Branhamella) catarrhalis;
  • for each member genus and species, the student will complete the following:
    • Characterize specimen collection techniques.
    • Describe culture media procedures for isolation.
    • Outline preliminary identification features (screening).
    • Describe colony morphology variation.
    • List steps for serologic classification
    • Identify key biochemical reactions of the specific species.
  • list nonbiochemical identification tests.
• Staphylococci and Micrococci:
  • differentiate the Staphylococcus aureus from other staphylococci and micrococci;
  • describe morphology and general characteristics of staphylococci and micrococci;
  • differentiate coagulase negative staphylococci;
  • discuss Staphylococcus aureus regarding its structure and extracellular products;
  • list and outline: identification techniques for Staph aureus, Staph epidermidis, and Staph saprophyticus;
  • discuss antibiotic susceptibility of Staph aureus;
  • compare hemolytic differences among these organisms;
  • describe the coagulase test reactions of species listed;
  • list the significant ingredients and the results obtainable from the blood agar plate, coagulase test, Mannitol salt agar and DNase test;
  • list pathological conditions caused by Staphylococcus aureus;
  • state the primary pathological condition caused by: (1) Staphylococcus epidermidis and (2) Staph saprophyticus; and
  • list the areas of the human body to which staphylococcus is indigenous.
• Streptococci, Including Enterococci and Pneumococci:
  • describe the procedure for distinguishing between the genus Staphylococcus and the genus Streptococcus;
  • list several species of the genus Streptococcus;
  • classify Streptococci according to their hemolytic reactions on blood agar;
  • outline presumptive identification procedures used for streptococci. e. Discuss epidemiology and pathogenic mechanisms of the genus Streptococcus;
  • describe beta-hemolytic streptococci susceptibility differences to the antibiotic bacitracin or “A” disk test;
  • list diseases caused by beta hemolytic Group A Streptococcus;
  • outline and describe the tests or procedures for the identification of Streptococcus pyogenes, Streptococcus agalactiae, Enterococcus faecalis, Streptococcus pneumoniae, and Streptococcus viridans;
  • characterize Lancefield’s serological identification using specific organisms as examples;
  • list specific culture media and reagents for the identification of Group A Beta Hemolytic Streptococci (Streptococcus pyogenes).  Indicate why identification of a specific streptococcus group necessary for proper antimicrobial therapy and control of some infections;
  • discuss the pathological significance of the capsule;
  • describe differences in optochin susceptibility or “P” disk test in alpha-hemolytic streptococci; and
  • differentiate pneumococci from other alpha-hemolytic streptococci.
• Gram Positive Bacilli: aerobic spore forming Bacillus, aerobic non- spore forming Corynebacterium, Listeria, and others:
  • characterize the genus Bacillus;
  • list the forms of anthrax which can occur in humans;
  • outline identification methods for B. anthracis B.cereus;
  • list common genera of the aerobic, non-spore forming group of Gram positive bacilli;
  • discuss epidemiology and pathogenesis of Listerosis;
  • outline laboratory identification of Listeria monocytogenes;
  • characterize the genus Corynebacterium;
  • discuss the term diphtheroid and how it relates to the Corynebacteria;
  • outline isolation procedures of C. diphtheriae from suspected clinical material;
  • list type of infections caused by C. diphtheriae and control measures;
  • outline the pathogenesis of Nocardia infection; and
  • list laboratory identification procedures of Nocardia including microscopic and cultural features.
• Spirochetes (Treponema, Borrelia, and Leptospira):
  • state the main features of the Spirochaetaceae family.
  • be able to describe Treponema, Borrelia, and Leptospira based upon cell morphology;
  • state the difficulties associated with Gram staining spirochetes and cultivating in the lab;
  • describe the pathogenesis of infection caused by the various Treponema species;
  • list the tests both treponemal and non-treponemal used to identify Treponema pallidum;
  • state the main features of Borrelia recurrentis and pathogenesis of relapsing fever;
  • discuss Lyme disease caused by Borrelia burgdorferi including diagnostic procedures;
  • briefly describe the disease and identifying characteristics the disease and identifying characteristics of Leptospira interrogans; and
  • list the animal reservoirs of Leptosporosis.
  • state the important features of Weil’s Syndrome.
• Bioterrorism:
  • define the term bioweapon;
  • list the significant agents (microorganisms or toxins) which may be potential biological weapons;
  • define the terms that are primary factors of bioweapons including infectivity, pathogenicity, virulence, toxicity, transmissibility, and incubation period;
  • describe the role of the smallpox virus as a potential biological weapon;
  • state the mechanisms of disease production by Bacillus anthracic and how it has been used as a bioweapon in the past and present;
  • discuss the role of vaccination in the prevention of smallpox and anthrax outbreaks; and
  • give the rationale behind the use of Clostridium botulinum toxin as an effective bioweapon.

 

Prerequisites: ML 218, ML 219
Corequisites: ML 229
S (N)