ML 228 - Clinical Microbiology II Lecture
Credit Hours: 2
Continuation of ML 218 with the discussion of the pathogenesis and identification of specific microorganisms isolated from clinical specimens according to the ASCP Board of Registry Guidelines for CLT curriculum. A taxonomic approach will be used in presenting the groups of microorganisms.
Upon completion of this course, the student will be able to:
- 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;
- list the animal reservoirs of Leptosporosis; and
- state the important features of Weil's Syndrome.
- 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, BI 147, BI 148
Corequisites: ML 229