A 63 year old man presents to the ED with a severe headache, fever, and mental statues changes. Upon examination, the patient has signs and symptoms of endocarditis. Thereis no evidence of increased intracranial pressure. There is no nuchal rigidity. There are no signs of IV drug abuse.
Which pattern would you expect to find from the initial diagnostic workup:
a. Single frontal abscess: CSF with decreased glucose, increased protein content
b. Thickened lepto-meninges: CSF with normal glucose and slightly elevated protein content
c. Multiple small abscesses: CSF with increased protein content and increased PMNs
d. Diffuse inflammatory brain parenchyma: CSF with increased RBCs and decreased protein content
Blood cultures are obtained before antibiotic therapy starts. Which organism is the most likely pathogen to be isolated?
b. Pseudomonas aeruginosa
c. Staph aureus non-MecA variant
Multiple small abscesses: CSF with increased protein content and increased PMNs
Staph aureus non-MecA variant
Which aseptic meningitis pattern requires antimicrobial therapy to prevent progression into encephalitis?
A. HSV type 1
A frankly purulent CSF sample requires what kind of follow up?
C. Reporting to the Health Department followed by prophylaxis of the patient's contacts
Which one of the following statements about impetigo is false?
B. It is a severely impairing disease with significant mortality
A 39 year old man presents to the outpatient department with redness on his right thigh. The patient has a fever and does not feel well. The affected area is warm to the touch and crackles when examined. It is hard to determine where the lesion starts and the unaffected skin ends. The patient relates that the lesion has enlarged since he noticed it in the morning. Answer the following three questions:
What is the patient's diagnosis?
b. S. aureus-induced psoriasis
c. Anerobic cellulitis
d. Scalded skin syndrome
Antimicrobial therapy does not need to cover which one of these potential pathogens?
b. Aerobic gram positive cocci
c. Microaerophilic Streptococcus
d. Keratin loving fungi
What therapeutic option is best for this patient?
a. Immediate discharge on oral antibiotics
b. Admission for IV antibiotics
c. Observation with a prescription to start antibiotics if the fever persists
d. Leg amputation
Keratin loving fungi
Admission for IV antibiotics
A red lesion of the skin that can only be seen but not felt is called:
Which of the following statements about ulcers is true:
C. Can reach the fascia at the base layer of the skin
Which of the following pathogens is most commonly associated with cardiac tamponades?
B. Influenza A
A patient with end stage renal disease on continuous ambulatory peritoneal dialysis is suffering from peritonitis. A gram stain of the ascites fluid is negative. Which organism would you expect to find from a culture of the fluid incubated in BAP?
C. S. epidermidis
A 45 year old male with high risk sexual behavior complains of pain in his left knee. Isolating the most likely pathogen would require which one of the following sets of conditions:
D. Thayer Martin agar plates
Which one of the following procedures is an example of a clean-contaminated operation?
B. Uncomplicated appendectomy - hernia repair is clean, gallbladder removal is contaminated
A 78 year old patient compains of a very painful axilla. On examination, a hair follicle is enlarged, redden and exquisitely painful. Which one of the following organisms is the most likely pathogen?
D. S. aureus
A 56 year old female present to the office with erythema on her cheeks and legs. The lesions are well demarcated and there are no vesicles. Which one of the following organisms is the most likely pathogen?
C. Strep pyogenes (GAS)
What defines early onset neonatal meningitis?
D. Meningitis <7 days after childbirth
A vaccine has been effective in reducing the incidence of meningitis due to which one of the following pathogens?
D. H. influenzae type B
Profound leukocytosis is found in which one of the following encephalitis presentations?
B. Eastern equine encephalitis
A 28 year old patient who has a history of IV drug abuse is suffering from mental status changes. An MRI shows signs of a large abscess near the central cerebral artery. There is a heart murmur. Neurosurgery debrides the would and leaves a drain. Some of the tissue is sent to the lab for gram stain and culture. What would you expect to find on the gram stain?
C. Gram negative rods and PMNs
What is the most common type of culture used to determine the pathogen causing osteomyelitis?
A. Blood culture
A patient with peritonitis has an ascites culture done which grows a mixture of gram positives and gram negatives. An anaerobic culture also has growth. What is the most likely etiology of this peritonitis?
C. Peritonitis secondary to a perforated bowel diverticulum
A 25 year old female became ill with nausea, vomiting, and cramping 4 hours after having attended a party as a well known restaurant. Within 24 hours, her symptoms had resolved and she was able to eat and drink. Several other guests who attended the party had also gotten ill. The NYS Department of Health was brought in to investigate. They recovered a large spore-forming gram positive rod in the filling used to prepare the stuffed mushrooms.
What is the most likely cause of this infection?
a. Bacillus anthracis
b. Bacillus cereus
c. Bacillus spoiligeous
What mechanism did the bacteria use to cause the patient to become ill?
a. Emetic toxin
Emetic toxin (1-6 hours)
How do we screen for Bacillus cereus in the lab?
Bacillus anthracis causes three forms of anthrax.
Inhalation anthrax (Woolsorters Disease)
You have filamentous colonies on a BAP. The gram stain of the bacteria shows a large spore-forming gram positive rod. The catalase test is performed and it is positive. What other two colony characteristics would you look for that could suggest you might have Bacillus anthracis?
Medusa head, comma shaped
A gram positive rod is recovered from a necrotic ulcer. The gram stain and culture morphology is suggestive of Bacillus anthracis. When working with this organism, what precautions should be taken?
D. A biological safety hood along with PPE should be used
What is the second most common contaminate found in bacterial cultures?
A. Corynebacterium spp.
This organism has a mildew odor.
This organism looks like Chinese letters in the gram stain.
This organism causes Bacterial Vaginosis.
This organism causes Woolsorter's Disease.
This organism is an opportunistic pathogen in hospitalized patients.
This organism is normal vaginal flora.
This organism is associated with clue cells.
This organism causes erysipeloid.
This organism produces large amount of toxin.
Corynebacterium diphtheriae gravis
PF + LF = EF
Which organism is associated with this equation?
The symptoms from this organism mimic GAS.
Which enriched media(s) is/are used to isolate Corynebacterium diphtheriae?
A. Loeffler's Agar - used for isolation; Tinsdale agar is differential
A small gram positive rod isolated from a throat culture collected postmortem was suspected to be Corynebacterium diphtheriae. It was subcultured to Tellurite selective media. Which of the following describes colony morphology that would be consistent with diphtheriae?
B. Brown/black colonies with black halo
A diagnosis of diphtheriae can be made when what clinical symptom is observed?
Pseudomembrane on the tonsils/throat.
What type of stain(s) could be used to show the metachromatic granules that are characteristic of Corynebacterium?
a. Gram stain
b. Kinyoun stain
c. Babes-Ernst stain
d. Trichrome stain
e. Methylene blue stain
f. Toluidine O stain
Babes-Ernst stain, Methylene blue stain, Toluidine O stain
Which Corynebacterium is highly resistant to antibiotics, transfer resistance to other organisms, and is extremely important to identify in the hospital setting?
B. C. jeikeium
The colony morphology of Listeria monocytogenes looks very similar to what other bacteria?
D. Strep agalactiae (GBS)
List 4 groups of individuals that have increased risk of becoming infected with Listeria.
A gram positive rod was recovered in a blood culture from a 28 year old female that was 4 months pregnant. It grew on BAP at 24 hours in CO2. It was suspected to be Listeria monocytogenes. Which combination of growth characteristics and biochemical reactions would confirms the technologist's suspicions?
D. Beta hemolytic, catalase positive, motile, esculin positive, and H2S negative
A small gram positive rod was isolated from a puncture wound on a male patient. He had recently been working at a slaughter house and stuck a meat hook into his right thigh which became infected. The following colony morphology and biochemical reactions were recorded. Which would be consisten with Erysipelothrix?
B. Alpha hemolytic, catalase negative, nonmotile, esculin negative, H2S positive
How can an individual become infected with Listeria?
Listeria is a food contamination - infection may occur by ingestion
Erysipelothrix is primarily a pathogen of what group?
C. Pigs and turkeys
Animals that become infected with Erysipelothrix have the following symptoms: diarrhea, fever, septicemia, arthritis, lesions, and anorexia. What is this disease called?
Which organism is reverse CAMP test positive?
Long thin chaining gram positive rods are characteristic of which of the following?
B. Lactobacillus species
Which two characteristics are true to Gardnerella?
a. Pinpoint colonies after 48 hours
b. Catalase positive
c. Esculin positive
d. Pleomorphic gram variable coccobacillus
Pinpoint colonies after 48 hours, pleomorphic gram variable coccobacillus
A 25 year old patient presented to his physician with a large lump on the lower right jaw. The lump began as a small nodule under the skin and over time had grown so that it could easily be seen. Upon physical exam, the lump was hard to the touch. A biopsy was performed and revealed dense fibrotic tissue. Additional material was removed from the more purulent center and sent for lab testing.
From this particular site, what organism should the lab suspect?
What might they find in the material that would be diagnostic for this organism?
What would the gram stain look like?
How should the material that is plated by incubated?
What would a typical colony look like?
The lab should suspect an aerobic Actinomyces spp.
Within the material there is likely to be sulfur granules.
The gram stain shows a dense, dark mycelia surrounded by gram negative rods.
The materila should be incubated in both aerobic and anaerobic conditions at 37C.
A colony of Actinomyces spp. would have a molar tooth looking colony.
Which organisms are partially acid fast?
Nocardia, Rodococcus, Gordonia, Tsukamurella
Nocardia is ubiquitous in nature. It is not very virulent but does cause infection in what type of patient? What is the most common disease caused by Nocardia?
Will cause infection in patients with chronic pulmonary disease.
Most common disease is pneumonia.
What two organisms cause a subcutaneous infection called Madura Foot?
Nocardia and Actinomadura
What characteristics do branching gram positive rods share with fungi?
a. Grow on fungal media
b. Colony morphology resembles fungal growth
c. Produce aerial hyphae
d. Both are acid fast organisms
e. Slow growing
Grow on fungal media, colony morphology resembles fungal growth, produce aerial hyphae, slow growing
Streptomyces rarely causes disease even though they are frequently found in nature. How has medicine benefited from these organisms?
Streptomyces is known for its production of many antibiotics (Streptomycin, Erythromycin, etc). This is due to its secondary metabolism and has been a huge benefit to medicine.
What biochemical tests are used to differentiate branching gram positive rods?
B. Tyrosine, xanthine, casein, starch
When a physicial requests a culture for Nocardia or Streptomyces, what type of media can be used for primary recovery and isolation?
D. BCYE agar
Rodococcus, Gordonia, and Tsukamurella are hard to characterize biochemically. What three characteristics are used to identify them?
B. Gene sequencing, colony morphology, acid fast stain results
Actinomadura microscopic morphology helps to differentiate it from other aerobic gram positive rods. Which of the following is characteristic for Actinomadura?
B. Filamentous gram positive rods with chains of conidia
It is difficult to treat infections caused by Streptomyces. What is the recommended duration of therapy in these cases?