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.

Course Outcomes
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; and
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; and
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; and
- 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.

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 anthracis 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 anthracis 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
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