Question 1

After 48 hours of incubation,black colonies with a dark brown halo are observed on Tinsdale agar.What type of toxin does this organism produce?

Accepted Answer

A) Emetic toxin 
B) Exotoxin 
C) Enterotoxin 
D) Endotoxin 
A) Emetic toxin 
B) Exotoxin 
C) Enterotoxin 
D) Endotoxin B

Question 2

The isolation of a small gram-positive,catalase-positive rod with a narrow zone of hemolysis isolated from blood or CSF should be used as strong presumptive evidence for:

Accepted Answer

A) listeriosis. 
B) diphtheria. 
C) pertussis. 
D) tetanus. 
A) listeriosis. 
B) diphtheria. 
C) pertussis. 
D) tetanus. A

Question 3

A pharyngeal specimen is inoculated on cystine-tellurite blood agar,modified Tinsdale agar,and MacConkey agar.After 48 hours of incubation,black colonies with a brown halo are observed on the Tinsdale agar and gray colonies are isolated from the cystine-tellurite agar.However,no growth is observed on the MacConkey agar.Which one of the following statements explains this discrepancy?

Accepted Answer

A) The MacConkey agar is most likely expired. 
B) The MacConkey agar should be incubated an additional 24 hours to observe growth. 
C) The pH of the media may be altered,causing an environment that is too acidic for the organism to grow. 
D) No discrepancy is present;this organism does not grow on MacConkey agar. 
A) The MacConkey agar is most likely expired. 
B) The MacConkey agar should be incubated an additional 24 hours to observe growth. 
C) The pH of the media may be altered,causing an environment that is too acidic for the organism to grow. 
D) No discrepancy is present;this organism does not grow on MacConkey agar. D

Question 4

The organism that exhibits characteristic end-over-end tumbling motility when incubated in nutrient broth at room temperature for 1 to 2 hours is:

Accepted Answer

A) L.monocytogenes. 
B) Corynebacterium diphtheriae. 
C) Bacillus anthracis. 
D) Bacillus cereus group 
A) L.monocytogenes. 
B) Corynebacterium diphtheriae. 
C) Bacillus anthracis. 
D) Bacillus cereus group

Question 5

A middle-aged women presented to the emergency room complaining of cramping and gastrointestinal discomfort.She had recently attended a family reunion the past weekend.The event was a picnic where potato salad,hamburgers,deviled eggs,hot dogs and chips were served.A feces culture was requested resulting in no growth.What would be the next recommended follow-up testing?

Accepted Answer

A) Serologic testing for IgM and IgG 
B) No follow-up testing required 
C) Collect an additional specimen and attempt to cultivate on specialized media 
D) Treat the patient with ampicillin 
A) Serologic testing for IgM and IgG 
B) No follow-up testing required 
C) Collect an additional specimen and attempt to cultivate on specialized media 
D) Treat the patient with ampicillin

Question 6

Patients who are immunocompromised and women who are pregnant should avoid eating soft cheeses such as Mexican-style,feta,Brie,Camembert,and blue-veined cheeses to prevent:

Accepted Answer

A) food-borne listeriosis. 
B) staphylococcal food poisoning. 
C) gastric gangrene. 
D) Salmonella infection. 
A) food-borne listeriosis. 
B) staphylococcal food poisoning. 
C) gastric gangrene. 
D) Salmonella infection.

Question 7

A catalase-positive,gram-positive bacillus that is not acid-fast,does not branch,and does not form spores could possibly belong to which group of bacteria?

Accepted Answer

A) Corynebacterium 
B) Bacillus 
C) Actinomyces 
D) Mycobacterium 
A) Corynebacterium 
B) Bacillus 
C) Actinomyces 
D) Mycobacterium

Question 8

A cerebrospinal fluid (CSF)culture was performed on a newborn in distress.After overnight incubation,small gram-positive bacilli with a soft zone of β-hemolysis grew on sheep blood agar.Based on this information,what results would be expected on the following tests: hippurate;Christie,Atkins,Munch-Petersen (CAMP);and motility?

Accepted Answer

A) Negative hippurate,positive CAMP,and negative motility 
B) Positive hippurate,negative CAMP,and positive motility 
C) Positive hippurate,positive CAMP,and positive motility 
D) Negative hippurate,negative CAMP,and negative motility 
A) Negative hippurate,positive CAMP,and negative motility 
B) Positive hippurate,negative CAMP,and positive motility 
C) Positive hippurate,positive CAMP,and positive motility 
D) Negative hippurate,negative CAMP,and negative motility

Question 9

Bacteria described as being coryneform have which of the following morphologic features?

Accepted Answer

A) Squared rods with squared ends arranged in pairs 
B) Short gram-positive cocci in branching chains 
C) Resemble and are often referred to as Chinese letters 
D) Long branching gram-positive bacilli 
A) Squared rods with squared ends arranged in pairs 
B) Short gram-positive cocci in branching chains 
C) Resemble and are often referred to as Chinese letters 
D) Long branching gram-positive bacilli

Question 10

A gram-positive bacillus,which grew on Tinsdale agar,is esculin hydrolysis-negative,urease-positive,and nonlipophilic.The organism can be identified as:

Accepted Answer

A) C.diphtheria. 
B) Corynebacterium glucuronolyticum. 
C) Corynebacterium xerosis. 
D) Corynebacterium ulcerans. 
A) C.diphtheria. 
B) Corynebacterium glucuronolyticum. 
C) Corynebacterium xerosis. 
D) Corynebacterium ulcerans.

Question 11

A 13-year-old girl presented to her physician complaining of being tired,having a mild sore throat and fever.She appears to have a grey coating on her tonsils when examined by the physician.The most logical etiologic agent associated with the patient's illness is:

Accepted Answer

A) Streptococcal pharyngitis. 
B) diphtheriae. 
C) scarlet fever. 
D) Tonsillitis. 
A) Streptococcal pharyngitis. 
B) diphtheriae. 
C) scarlet fever. 
D) Tonsillitis.

Question 12

Quality control is set up on urea media.Which two organisms should be used to determine the validity of the media?

Accepted Answer

A) C.ulcerans and C.diphtheria 
B) C.diphtheria and Streptococcus pneumoniae 
C) C.ulcerans and Corynebacterium pseudotuberculosis 
D) C.glucuronolyticum and C.ulcerans 
A) C.ulcerans and C.diphtheria 
B) C.diphtheria and Streptococcus pneumoniae 
C) C.ulcerans and Corynebacterium pseudotuberculosis 
D) C.glucuronolyticum and C.ulcerans

Exam 15: Listeria Corynebacterium and Similar Organisms

After 48 hours of incubation,black colonies with a dark brown halo are observed on Tinsdale agar.What type of toxin does this organism produce?

The isolation of a small gram-positive,catalase-positive rod with a narrow zone of hemolysis isolated from blood or CSF should be used as strong presumptive evidence for:

The organism that exhibits characteristic end-over-end tumbling motility when incubated in nutrient broth at room temperature for 1 to 2 hours is:

Patients who are immunocompromised and women who are pregnant should avoid eating soft cheeses such as Mexican-style,feta,Brie,Camembert,and blue-veined cheeses to prevent:

A catalase-positive,gram-positive bacillus that is not acid-fast,does not branch,and does not form spores could possibly belong to which group of bacteria?

Bacteria described as being coryneform have which of the following morphologic features?

A gram-positive bacillus,which grew on Tinsdale agar,is esculin hydrolysis-negative,urease-positive,and nonlipophilic.The organism can be identified as:

A 13-year-old girl presented to her physician complaining of being tired,having a mild sore throat and fever.She appears to have a grey coating on her tonsils when examined by the physician.The most logical etiologic agent associated with the patient's illness is:

Quality control is set up on urea media.Which two organisms should be used to determine the validity of the media?

Microbial Taxonomy

Bacterial Genetics, metabolism, and Structure

Host-Microorganism Interactions

Laboratory Safety

Specimen Management

Role of Microscopy

Traditional Cultivation and Identification

Nucleic Acid-Based Analytic Methods for Microbial Identification and Characterization

Overview of Immunochemical Methods Used for Organism Detection

Principles of Antimicrobial Action Resistance

Laboratory Methods and Strategies for Antimicrobial Susceptibility Testing

Staphylococcus, Micrococcus, and Similar Organisms

Streptococcus, Enterococcus, and Similar Organisms

Bacillus and Similar Organisms

Erysipelothrix, Lactobacillus, and Similar Organisms

Nocardia, Streptomyces, Rhodococcus, Oerskovia, and Similar Organisms

Enterobacteriaceae

Acinetobacter, Stenotrophomonas, and Other Organisms

Pseudomonas, Burkholderia, and Similar Organisms

Achromobacter, Rhizobium, Ochrobactrum, and Similar Organisms

Chryseobacterium, Sphingobacterium, and Similar Organisms

Alcaligenes, Bordetella Nonpertussis, Comamonas, and Similar Organisms

Vibrio, aeromonas, Plesiomonas Shigelloides, and Chromobacterium Violaceum

Sphingomonas Paucimobilis and Similar Organisms

Moraxella

Eikenella Corrodens and Similar Organisms

Pasteurella and Similar Organisms

Actinobacillus, Kingella, Cardiobacterium, Capnocytophaga, and Similar Organisms

Haemophilus

Bartonella and Afipia

Campylobacter, Arcobacter, and Helicobacter

Legionella

Brucella

Bordetella Pertussis and Bordetella Parapertussis

Francisella

Streptobacillus Moniliformis and Spirillum Minus

Neisseria and Moraxella Catarrhalis

Overview and General Considerations

Laboratory Considerations

Mycobacteria

Obligate Intracellular and Non-culturable Bacterial Agents

Cell Walldeficient Bacteria: Mycoplasma and Ureaplasma

The Spirochetes

Overview of the Methods and Strategies in Parasitology

Intestinal Protozoa

Blood and Tissue Protozoa

Protozoa From Other Body Sites

Intestinal Nematodes

Tissue Nematodes

Blood Nematodes

Intestinal Cestodes

Tissue Cestodes

Intestinal Trematodes

Liver and Lung Trematodes

Blood Trematodes

Overview of Fungal Identification Methods and Strategies

Hyaline Molds, Zygomycetes, Dermatophytes, and Opportunistic and Systemic Mycoses

Dematiaceious Molds

Opportunistic Atypical Fungus: Pjirovecii

The Yeasts

Anti-fungal Susceptibility Testing, therapy, and Prevention

Overview of the Methods and Strategies in Virology

Viruses in Human Disease

Antiviral Therapy Susceptibility Testing and Prevention

Bloodstream Infections

Infections of the Lower Respiratory Tract

Upper Respiratory Tract Infections and Other Infections of the Oral Cavity and Neck

Meningitis and Other Infections of the Central Nervous Systems

Infections of the Eyes ears and Sinuses

Infections of the Urinary Tract