Case Studies in Clinical Microbiology (Online Course)

(based on 1201 customer ratings)

Authors: Elmer W. Koneman, MD; Christie A. Grueser, MSS, MT
Reviewer: Judi Bennett, MT, BSM

Do you want to challenge your knowledge of those classic clinical microbiology topics? Do your collegues always look to you as the local expert on bacteria? Then, Case Studies in Clinical Microbiology is the course for you! This newly revised and updated interactive microbiology course contains classic case studies and covers 10 common but important topics topics, including ESBL- producing strains, MRSA, neonatal meningitis, and much more. Whether you are a student or practicing clinical microbiologist, this is a great way to earn a full 3 hours of P.A.C.E. approved CE credits that are sure to satisfy your need for all things microbiology. Subscribe today!

See all available courses »

Continuing Education Credits

  • P.A.C.E.® Contact Hours: 3 hour(s)
  • Florida Board of Clinical Laboratory Science CE - General (Microbiology/Mycology/Parasitology): 3 hour(s)


  • Correlate presenting clinical signs and symptoms with the organism identifications for the cases being presented.
  • Outline the presumptive and definitive characteristics for the laboratory identification of the bacterial species being presented.
  • Discuss the diagnostic and therapeutic implications of making a correct organism identification.

Customer Ratings

(based on 1201 customer ratings)

Course Outline

  • Introduction
      • Course Organiztion
  • Acute Urethral Discharge
      • Case Study: Acute Urethral DischargeA 25-year-old female presents to the emergency room with an acute urethral discharge of two days duration.The imag...
      • Neisseria gonorrhoeae
      • Neiserria gonorrhoeae is the most common cause of septic arthritis in the United States.
      • Presumptive Laboratory Identification: Neisseria gonorrhoeae
      • Additional Testing Information
      • The positive oxidase reaction as shown in the image (yellow arrow) rules out which of the following two look-alike organisms of N. gonorrhoeae? (Choos...
      • Definitive Laboratory Identification: Neisseria gonorrhoeae
      • The carbohydrate utilization reaction seen in the image will ALONE provide the necessary testing required for a definitive identification of N. gonorr...
  • Acute Onset Pneumonia
      • Case Study: Acute Onset PneumoniaA 70-year-old transient with a productive cough, pleuritic chest pain radiating to the mid back, fever, and chills wa...
      • Case Study, Part Two: Acute Onset PneumoniaA 70-year-old transient with a productive cough, pleuritic chest pain radiating to the mid back, fever, and...
      • Streptococcus pneumoniae
      • Streptococcus pnemoniae is the most common cause of community-acquired pneumonia.
      • Pneumococcal vaccine is particularly effective in children less than two years of age.
      • Laboratory Identification: Streptococcus pneumoniae
      • Case Study, Part Three: Acute Onset PneumoniaA 70-year-old transient with a productive cough, pleuritic chest pain radiating to the mid back, fever, a...
      • A drop of 10% deoxycholate was placed on an area of growth as shown in the image. This test is often used to differentiate S. pneumoniae from viridan...
      • Susceptibility Testing: Streptococcus pneumoniae
      • The zone of inhibition around the disk shown in the image has been measured at 23 mm. Based on this result, you should:
      • For S. pneumoniae isolates recovered from cerebrospinal fluid (CSF), the oxacillin screen test alone is NOT sufficient for determining susceptibility ...
      • Minimum inhibitory concentration (MIC) susceptibility tests should be performed against other beta lactam antibiotics on important S. pneumoniae isola...
      • Pneumococcal Resistance
  • Gram-Negative Sepsis
      • Case Study: Gram-Negative Sepsis A 67-year-old man is admitted to the hospital with a cough, right lower chest pain accentuated by deep breathing, and...
      • The reactions seen in the portion of the API strip shown in the image effectively rules out Escherichia coli.
      • Extended-Spectrum Beta-Lactamases (ESBLs) Review
      • Isolates of Escherichia coli, Klebsiella pneumoniae, K. oxytoca and clinically significant isolates of Proteus mirabilis may possess extended-spectrum...
      • Extended-Spectrum Beta-Lactamases (ESBLs)
      • Extended-Spectrum Beta-Lactamase (ESBL) Screening by Disk Diffusion
      • ESBL Screening by Broth Microdilution
      • Phenotypic Confirmation by Disk Diffusion and Reporting
      • Extended-Spectrum Beta-Lactamase (ESBL) Activity
      • Phenotypic Confirmation by Broth Microdilution and Reporting
  • Recurrent Urinary Tract Infection (UTI)
      • Case Study: Recurrent Urinary Tract Infection (UTI) A 72-year-old woman had a history of recurrent UTIs over the past several months, for which she ha...
      • Pyrrolidonyl Arylamidase (PYR) Differential
      • The spot test that is helpful in separating Enterococcus species (positive as shown in the image) from the viridans streptococci and S. pneumoniae (bo...
      • Enterococcus Identification
      • Enterococcus faecium Identification
      • Vancomycin Resistance
      • In this image is a quadrant plate containing brain heart infusion (BHI) agar supplemented with 6 ug/mL of vancomycin. The right upper quadrant was ino...
      • What is the most important modifiable risk factor for enteric colonization with vancomycin-resistant Enterococcus faecium (VREF)?
  • Acute Enteritis with Sepsis
      • Case Study: Acute Enteritis with Sepsis A 63-year-old man was seen in the emergency room with complaints of sudden onset of fever, chills, and abdomin...
      • The Gram stain shown in the image was prepared from a positive anaerobic blood culture bottle after 36 hours incubation. Based on the morphology of th...
      • Need for Identification and Further Investigation
      • Colony Morphology
      • Clostridium Quad Plate
      • Clostridium septicum RapID ANA
      • It is important to establish a species identification of C. septicum in blood culture isolates because of its close association with carcinoma of the ...
      • Match the species of anaerobes and frequently associated conditions.
      • Each of the following statements is true concerning Clostridium septicum infections EXCEPT:
  • Post Traumatic Wound Infection
      • Case Study: Post Traumatic Wound InfectionAn 18-year-old female incurred a deep penetrating injury of the dorsum of her right foot when a kitchen knif...
      • Staph on Blood Agar
      • The organisms shown in the image were observed in a smear prepared from the colony shown previous to this page. Which of the following tests will help...
      • The tube coagulase test, shown in the image (upper tube positive), should be performed on all S. aureus-suspicious isolates giving a negative slide co...
      • Staphylococcus aureus Mannitol
      • Methicillin-Resistant Staphylococcus aureus (MRSA) Screen
      • Methicillin-Resistant Staphylococcus aureus (MRSA) Disk Test
      • Predisposing Factors to MRSA Infection and Decreasing the Risk of Colonization
      • Factors predisposing to infections with methicillin resistant Staphylococcus aureus (MRSA) include: (choose all that apply)
      • Decreasing the risk of staphylococcal colonization of indwelling catheters in the future may involve:
      • Patients with infections with MRSA have uniformly poorer outcomes than those infected with sensitive strains.
      • Exfoliative Toxins Causing Staphylococcal Scalded-Skin Syndrome (SSSS)
      • The staphylococcal toxins causing the scalded skin syndrome (SSSS) have as their site of action in which of the following layers of skin:
  • Splenic Abscess
      • Case Study: Spleen SpecimenA 23-year-old man had complained of right lower quadrant abdominal pain for approximately one week. Initially the pain was ...
      • Most strains of S. anginosus (milleri) carry the F antigen (see image). Rare strains that carry the group A antigen can be differentiated from S. pyog...
      • S. anginosus ("milleri") CO2
      • S. anginosus ("milleri") Biochemicals
      • Streptococcus milleri Group
      • Most infections caused by S. anginosus can be effectively treated with penicillin or a first generation cephalosporin.
      • Epidural and subdural abscesses are clinical manifestations uncommon for S. anginosus ("milleri").
      • Which is a clinical condition often associated with Streptococcus anginosus ("milleri")?
  • Cellulitis
      • Case Study: CellulitisA 40-year-old woman with a long history of diabetes mellitis developed swelling and erythema of the left lower leg following sup...
      • Case Study: Cellulitis (continued)Beta hemolytic colonies grew from the blood culture bottle after 18 hours incubation (see image). Which of following...
      • Group A Strep A Disk/SXT
      • Thus, in follow-up to the previous discussion, the reaction shown in the image establishes the identification of a group A, beta hemolytic Streptococc...
      • Invasive Streptococcal Infection
      • Major Factors Related to Strong Resistance of Certain Strains of Group A Streptococci to Phagocytosis
      • What is a major complication of toxic shock syndrome related to group A streptococci, leading to 50% mortality?
      • What are the factors related to the strong resistance of certain strains of group A streptococci to phagocytosis? (Select all that apply.)
  • Neonatal Meningitis
      • Case Study: Neonatal Meningitis
      • Case Study: Neonatal Meningitis (continued) A Brown and Brenn Gram stain was performed on one of the tissue biopsy specimens. Organisms were seen as s...
      • Case Study: Neonatal Meningitis (continued) The top image of the surface of blood agar after 24 hours incubation at 35° C in 10% CO2, on which ar...
      • What test(s) which may be performed to establish a presumptive differential identification between group B streptococci and L. monocytogenes?
      • Listeria Gram stain
      • Shown in the image are three tubes: (1) motility agar (note subsurface flare shown by arrows); (2) esculin hydrolysis (+), and (3) VP (+). The reactio...
      • Listeria motility
      • Listeria monocytogenes
      • Listeria monocytogenes Virulence Factors
      • Listeria monocytogenes: Virulence Factors (continued)
      • Which of the following is NOT related to the virulence of Listeria monocytogenes?
      • Which of the following factors has NOT led to the current increase in incidence of listeriosis?
      • A characteristic of the virulence of L. monocytogenes is its unique ability to invade peripheral nerves and rapidly enter into the brain.
  • Cellulitis of the Arm
      • Cellulitis Lesion
      • Eikenella BAP
      • A bacterial isolate that produces pitting of the agar and has a bleach-like odor is probably E. corrodens. What are the closely related species that m...
      • Eikenella - Catalase & Oxidase
      • Eikenella Biochemicals
      • Which of the following result in most Eikenella cellulitis infections? 
      • In view of the feedback to the previous question, what is the most likely reason that the clinical correlation does not seem to fit in this case? ...
      • Eikenella corrodens Infections and Patients with Insulin-Dependent Diabetes Mellitus (IDDM)
      • Bite Wounds
      • Human bite wound infections are categorically more severe and more often lead to complications than infected bites from other animals.
      • To avoid infection with E. corrodens, what are patients with insulin-dependent diabetes mellitis (IDDM) advised NOT to do? (Select all that apply.)
  • References
      • References

Additional Information

Level of instruction: Intermediate
Intended Audience: Medical technologists, and instructors experienced in bacteriology, graduate students in microbiology, clinical pathologists, and infectious disease physicians.
General Information: This recently revised and updated course (2014) provides interactive case studies which cover pertinent current topics in clinical microbiology. Numerous images enhance the text and interactive questions help the student master the material.
Author information: Elmer W. Koneman, MD, is Professor Emeritus,  Department of Pathology, University of Colorado School of Medicine.  Residing in Breckenridge, CO,  Dr. Koneman is a Board Certified Pathologist and is author of numerous journal articles and books, including Koneman’s Color Atlas and Textbook of Diagnostic Microbiology,  6th Edition,  2006 (Lippincott).   Dr. Koneman is presently affiliated with the Colorado Association for Clinical Laboratory Education (CACMLE) and with Instructional Design Consultants, specializing in interactive training and distance learning in clinical microbiology. Ms. Grueser is also presently affiliated with Instructional Design Consultants. 
Reviewer information: Judi Bennett, MT, BSM is a Program Director for MediaLab, Inc. During her 25 year career in clinical laboratory science, she has served as Laboratory Manager, Senior System Analyst, Point-of-Care Coordinator, Microbiology Supervisor, and generalist. Judi has been a speaker at various LIS, AMT, and CLMA conferences and has been published in peer-reviewed publications.

Just one user? Visit for individual subscriptions.
Quadferm Carbohydrates

Listeria BA

Listeria Gram stain


Strep Gram

Image of <i>S. pneumoniae</i> courtesy of Wikimedia Commons

E. coli on MAC