Exam 2 Study Guide

A patient comes into the clinic complaining of frequent coughing sometimes coughing up blood, fever, night sweats. After receiving a positive acid-fast stain from a bronchoalveolar lavage sample, the patient was diagnosed with a disease most likely caused by
Mycoplasma pneumoniae
Neisseria meningitidis
Streptococcosu pneumoniae
Bacillus cereus
Mycobacterium tuberculosis

Mycobacterium tuberculosis

Corynebacterium species often appear as ______________ on Gram staining.
Short, thin gram-negative bacilli that appear in chains
Pleomorphic, gram-positive, club-shaped bacilli that appear in palisades or in "V" and "L" formations
Large square-ended, gram-positive or gram-variable bacilli in chains where the ends of the single cells fit snugly together
Branching gram-positive bacilli that appear as fine, intertwining, delicate filaments

Pleomorphic, gram-positive, club-shaped bacilli that appear in palisades or in "V" and "L" formations

All of the following diseases are associated with Neisseria gonorrhoeae EXCEPT
pelvic inflammatory disease
pharyngitis
urethritis
endocarditis
ophthalmia neonatorum

endocarditis

A 14-year-old girl is admitted to the hospital with a 3-week history of sore throat leading to significantly decreased oral intake. She reports worsening of a painful sore throat resulting in avoidance of nearly all oral intake and an associated 22-lb weight loss. She has presented to care twice, 2 weeks and 2 days earlier. During each of those visits, rapid group A streptococcal (GAS) antigen testing and follow-up GAS culture were negative. She was discharged with symptomatic care for presumed viral pharyngitis. She vomited twice but has not had fevers, cough, rash, or diarrhea. Her medical history is noncontributory. Her immunizations are up to date. She reports one lifetime sexual partner and reports condom use with every encounter. A throat swab cultured on ___ resulted in positive cultures for Neisseria gonorrhoeae which were confirmed after further workup. Due to these results the physician should recommend ___

modified thayer martin
prescribing antibiotics for a gonorrhoeae infection

A mycetoma was identified on a patient. When acquiring the pus from the mycetoma, you noticed orange granules that contained filamentous bacteria. They showed a weak gram stain with beaded Gram positive bacilli. What was the etiologic agent?
Corynebacterium jeikeium
Actinomadura
Streptomyces lydicus
Nocardia brasiliensis
Arcanobacterium haemolyticum

Nocardia brasiliensis

A patient came in complaining of chest pains and fever. Chest X-ray reveals some sort of pneumonia or upper respiratory infection. You consider the possibility of tuberculosis, so you perform an acid-fast stain and it resembles branching bacilli but only under weak acid. What is the most likely etiologic agent?


Nocardia cyriacigeorgica
Neisseria meningitidis
Streptococcus pneumoniae
Arcanobacterium haemolyticum

Nocardia cyriacigeorgica

A patient presents with a case of pharyngitis. After a careful pharyngeal swab, the Gram stain highlights diptheroids present in large numbers. However, knowing C. ulcerans species presents the same symptoms as C. diptheriae, what tests would distinguish between the two?
Tinsdale halo and nitrate
nitrate and urease
alkaline phosphatase and nitrate
Tinsdale halo and urease
glucose fermentation and tinsdale halo

Nitrate and Urease

The following forearm wound was found on a 48 yr old farmer with a history of type 2 diabetes, hypertension, and hypercholestoerolaemia. A sample from the wound produces the following Gram stain. Further testing stated it was nonmotile, catalase positive, gamma hemolysis. What is the most likely etiologic agent?


Nocardia brasiliensis
Bacillus anthracis
Listeria monocytogenes
Arcanobacterium haemolyticum

Bacillus anthracis

Which one of the following is Gram positive bacilli is associated with infections in neonates, pregnant women, elderly adults, and outbreaks of food contamination? Hint: it also displays a positive CAMP test in "block" pattern
Bacillus cereus
Corynebacterium diphtherium
Ersipelothrix rhusiopathiae
Listeria monocytogenes
Neisseria meningitidis

Listeria monocytogenes

The following organism is known to produce "a string of pearls" when plated on penicillin agar after a few hours. (Hint: normally the bacteria is susceptible to penicillin)
Kingella kingae
Bacillus cereus
Bacillus anthracis
Neisseria gonorrhoeae
Nocardia brasiliensis

Bacillus anthracis

A 18yr old college student presents with pharyngitis. A Gram stain of a pharyngeal swab demonstrates Gram positive bacilli, catalase negative, beta-hemolytic and reverse CAMP positive. What is the most likely etiologic agent?
Arcanobcaterium haemolyticum
Neisseria meningitidis
Streptococcus pneumoniae
Corynebacterium ulcerans
Corynebacterium diphtheriae

Arcanobcaterium haemolyticum

If a bacteria can synthesize the V factor, then it can also produce porphyrin which can be determined by putting it under UV lamp.

False

A patient came in complaining of painful urination and pressure in their urethra. The physician suspected it was the typical gram negative diplococci and knowing how sensitive it was to lysis immediately took a urethral swab and placed in transport media. Which of the following was the most likely media used?

- Stuart
- Hektoen Enteric agar
- MacConkey
- Cary-Blair
- Tryptic Soy broth

Stuart

An alcoholic came in to the dentist complaining of ulcerating and bleeding gums (trench mouth). Noticing the inflamed and bleeding gums, the dentist took an aspirate and performed a Gram stain. Under the microscope, you can see the morphology in the picture and notice the tapered ends. What is the most likely etiologic agent?

- Haemophilus ducreyi
- Enterobacter aerogenes
- Fusobacterium nucleatum
- Pseudomonas aeruginosa
- Streptococcus mutans

Fusobacterium nucleatum

The following bacteria can metabolize pyruvate into lactic acid and thus keep the pH lower in the vagina, thus minimizing fungal growth. It is also known as a probiotic

- Enterococcus
- Bacteriodes
- Lactobacillus
- Escherichia
- Clostridium

Lactobacillus

Which of the following statements about Neisseria gonorrhoeae is incorrect?

- untreated infections can result in pelvic inflammatory disease and epididymitis
- this organism is on the CDC urgent human threat list due to its high prevalence of antimicrobial resistance
- you shouldn't use cotton swabs to obtain sample
- most men who have infections do NOT have symptoms

most men who have infections do NOT have symptoms

A patient comes in with a clinical presentation of erysipelas mimicking a Streptococcus pyogenes infection. However, a Gram stain of an aspirate demonstrates non-branching Gram-positive bacilli with the same catalase results as Streptococci. What test would you perform next to identify the etiologic agent?

- motility test
- TSI looking for hydrogen sulfide production
- hippurate
- blood agar looking for hemolytic phenotypes
- bile esculin hydrolysis

TSI looking for hydrogen sulfide production

The following organism is found in human as the only natural host, transmitted by contaminated respiratory droplets, and presents a disease with a pseudomembrane near the tonsils. The patients can also present with what looks like a "bull neck" due to the inflammation in this region. What is the most likely etiologic agent that would also stain Gram positive?

- Corynebacterium diptheriae
- Neisseria meningitis
- Listeria monocytogenes
- Bacillus anthracis

Corynebacterium diptheriae

One way to differentiate between Listeria monocytogenes from Corynebacterium species is:

- catalase
- endospore stain
- Gram stain
- Motility at 25dC

Motility at 25dC

The organism develops satellite phenomenon around colonies of Staphylococcus aureus.

- Haemophilus influenzae
- Nocardia cyriacigeorgica
- Citrobacter freundii
- Klebsiella pneumoniae
- Neisseria meningitidis

Haemophilus influenzae

Serum from a patient vaccinated against Haemophilus influenzae type B should show the following results when mixed with bacteria of the same serotype of H. influenzae

(a: a sample with bright, irregularly scattered fluorescent patches against a dark background.
b: a more uniform, diffuse fluorescence across the entire area, without distinct patches.)

A

The following is a picture from a blood culture from a patient suffering with endocarditis. Normally this organisms can be found as normal flora in the nose, throat and mouth. What is the most likely etiologic agent considering the morphology seen towards the lower middle of the picture? (Gram stain showing 'Rosettes')

-Bacillus mycoides
- Cardiobacterium hominis
- Haemophilus influenzae
- Moraxella catarrhalis
- Kingella kingae

Cardiobacterium hominis

A Haemophilus species was streaked on a plate and impregnated disks containing either factor X and/or V was placed to determine the requirements of the species. After seeing the results, what species is most likely?

(Photo shows use of XV factor only)

- Haemophilus ducreyi
- Haemophilus pertussis
- Haemophilus parainfluenzae
- Haemophilus influenzae

Haemophilus influenzae

The vaccines that are used against Haemophilus influenzae and Neisseria meningitidis target which of the following?
- peptidoglycan
- RNA polymerase
- capsule
- hemolytic toxin
- fimbriae

Capsule

Which DNase positive organism's colony is not easily broken up and slides easily on the media when pushed, thus displaying the "hockey puck" characteristics?

- Salmonella enterica
- Moraxella catarrhalis
- Nocardia brasiliensis
- Neisseria meningitidis
- Bacillus anthracis

Moraxella catarrhalis

The following test is the best way to differentiate Kingella and Neisseria

- catalase
- oxidase
- Growth on Regan-Lowe agar
- growth on motility agar

Catalase

An 11-year-old male patient presented anorexia, weight loss and persistent cough with nocturnal paroxysms for the previous 4 weeks. He also reported occasional wheezing and chest tightness. He denied fever, chills, myalgia, sore throat, or rhinorrhea. The patient presented to his primary care physician 1 week prior with the same complaint, and was treated with amoxicillin, ebastine and bronchodilator therapy. The patient's symptoms did not improve with this regimen. The cough became more frequent, sometimes emetizing (vomiting) and with an end inspiratory whoop. He was vaccinated according to the National Vaccine Program.

Considering the symptoms, what media is the best choice to identify the organism considering it can be selective and differential due to its unique appearance on the media?

- Mannitol salt agar
- Bordet-Gengou
- Chocolate agar
- Buffered charcoal yeast extract

Bordet-Gengou

As an immunocompromised individual, which of the following organisms would you worry about getting infected via a diet of various deli meat sandwiches

- Listeria monocytogenes
- Salmonella enterica
- Corynebacterium striatum
- Cardiobacterium hominis
- Yersinia enterocolitica

Listeria monocytogenes

Which organism commonly causes food poisoning by consumption of foods containing excessive populations of organisms and preformed enterotoxin (i.e. sick because of ingestion of toxins on food)?

- Escherichia coli
- Shigella sonnei
- Bacillus cereus
- Salmonella enterica

Bacillus cereus

The following etiologic agent is commonly associated with cutaneous nodules that discharge "sulfur" granules

- Nocardia
- Edwardsiella
- Cardiobacterium
- Yersinia

Nocardia

The functionality of the lethal factor requires the presence of what other protein from Bacillus anthracis to form an active toxin?

- edema factor
- D-glutamic acid
- cyclic adenosine monophosphate
- protective antigen

Protective antigen

Diptheria is uncommon in the United States because

- the insect vector has been eliminated
- of routine use of an effective human vaccine
- aggressive antimicrobial therapy has nearly eliminated the bacteria
- of vaccination of the animal reservoir
- climate change has destroyed the insect vector environment

of routine use of an effective human vaccine

The following microorganism is responsible for causing a pseudomembrane in the posterior pharynx. On blood agar it appears as black colonies. What is the most likely etiologic agent?

- Cronobacter sakazakii
- Neisseria meningitidis
- Corynebacterium diptheriae
- Shigella sonnei

Corynebacterium diptheriae

The following organism can cause neonatal sepsis or meningitis, just like Group B Streptococcus.

- Listeria monocytogenes
- Arcanobacterium haemolyticum
- Staphylococcus aureus
- Corynebacterium striatum

Listeria monocytogenes

A 17-year-old male presented to an emergency department with a history of multiple episodes of febrile pharyngitis followed in 10 to 14 days by extensive desquamation of his hands and feet. The reoccurrences have followed several courses of antimicrobial therapy, including amoxicillin and cephalosporins. Rapid group A streptococci screens and cultures have been consistently negative for Streptococcus pyogenes. A specimen with a request for an alternative agent is submitted to a reference laboratory, and the results listed below are observe:

The patient was subsequently treated with erythromycin, and he recovered. What was the etiologic agent?

SBA: small, slightly hemolytic colony, which at 48 hours is a dark spot sunken in the agar
Catalase -
Nitrate -
Reverse CAMP +

- Corynebacterium pseudodipthericum
- Legionella pneumophila
- Bordetella pertussis
- Corynebacterium striatum
- Arcanobacterium haemolyticum

Arcanobacterium haemolyticum

The following Gram stain was made of a conjunctival swab that identified a very unusual etiologic agent of conjunctivitis. The Gram stain appear over decolorized resulting in a mix population when it should show all purple. Looking at the Gram stain and NOT focusing on the disease, what genera BEST associates with the results below

- Bacillus
- Morganella
- Kentucky (fried chicken)
- Eikenella
- Corynebacterium

Corynebacterium

All of the following organisms have exotoxins that are required for their disease and therefore have lab techniques designed to detect them except:

- Bordetella pertussis
- Neisseria meningitidis
- EHEC
- Corynebacterium diptheriae

Neisseria meningitidis

A previously healthy man came into the clinic an abscess on his upper arm. The abscess had tiny white granules in it. An aspirate from his arm grew a velvety white colony after 4 days. Gram stain appeared as branching Gram-positive bacilli. Further analysis exhibited partially acid-fast organism. The most likely identification is:

- Capnocytophaga canimorsis
- Actinomadura madurae
- Nocardia brasiliensis
- Yersinia pseudotuberulosis
- Neisseria meningitidis

Nocardia brasiliensis

In the United Kingdom, a six year old horse was referred to the hospital due to nasal discharge for 10 days. The picture below was obtained from a endoscopy showing a diphtheritic-like membrane. The nasal swab exhibited a Gram-positive bacilli that grew a black colony with a brown halo on Tinsdale medium. Further lab work showed urease positive and acid production from starch. Which of the following organisms is the most likely etiologic agent?

- Aggregatibacter actinomycetemcomitans
- Corynebacterium ulcerans
- Corynebacterium diptheriae
- Citrobacter freundii

Corynebacterium ulcerans

A 30 yr old woman comes into the clinic complaining of a white vaginal discharge and the clinician reports a smell representing volatile amines. The Gram stain comes back with mixture of bacteria including Gram positive and negative cocci and bacilli. However, after a wet mount you notice the presence of vaginal epithelial cells covered in bacteria (aka Clue cells). What is the most probable etiologic agent that exhibits a Gram variable bacilli, catalase negative, Hippurate positive, and slow growing with gamma hemolysis?

- Neisseria gonorrhoeae
- Lactobacillus acidophilus
- Proteus mirabilis
- Staphylococcus saprophyticus
- Gardnerella vaginalis

Gardnerella vaginalis

Some organisms secrete phospholipase D or C (e.g. Arcanobacterium) which are known to ___________ the hemolytic patterns of Staphylococcus aureus

INHIBIT

A gardener came in with major swelling on his left hand and diagnosed as an erysipeloid. After a Gram stain it appears as a Gram positive pleiomorphic bacilli. H2S production would be the best test to confirm if the organism was Erysipelothrix or another catalase ____________Gram-positive bacilli

NEGATIVE

Serum from a patient unvaccinated against Haemophilus influenzae type B should show the following results when mixed with H. influenzae type B.

(a: a sample with bright, irregularly scattered fluorescent patches against a dark background.
b: a more uniform, diffuse fluorescence across the entire area, without distinct patches.)

B

All of the following bacteria have demonstrated high levels of antibiotic resistance EXCEPT

- Neisseria gonorrhoeae
- Enterobacter aerogenes
- Neisseria meningitidis
- Klebsiella pneumoniae

Neisseria meningitidis

Neisseria meningitidis can grow on blood agar, though N. gonorrhoeae does not

False

Which of the following is a requirement to be pathogenic for Neisseria gonorrhoeae?

- pili
- stx
- flagella
- IgE protease

Pili

Military barracks and college dorms are most at risk of acquiring meningitis from the following etiologic agent:

- Haemophilus pneumoniae
- Klebsiella pneumoniae
- Plesiomonas shigelloides
- Neisseria meningitidis

Neisseria meningitidis

The most common disease presentation of Moraxella catarrhalis in children is

- arthritis
- pharyngitis
- otitis media
- pericarditis

otitis media

Which of the following is the most reliable test to differentiate Neisseria lactamica from Neisseria meningitidis?

- nitrite reduction to nitrogen gas
- lactose fermentation
- growth of modified Thayer-Martin agar
- acid from maltose

lactose fermentation

The majority of Enterobacteriaceae members share all of the following general characteristics except

- glucose fermenters
- nitrate reducing
- Gram negative
- oxidase positive
- motile

Oxidase positive

At what stage of disease does the typical "whooping" cough present itself?

- catarrhal
- convalescent
- paroxysmal

Paroxysmal

In class, we talked about the following article:
Heterotopic ossification with concurrent chronic osteomyelitis of the leg following licking of a wound by a domesticated dog
Due to the transmission route in this case study, what is the most likely etiologic agent?

- Moraxella
- Bacillus
- Yersinia
- Pasteurella

Pasteurella

The porphyrin test was devised to detect strains of Haemophilus capable of:

- utilizing maltose
- production of beta-lactamase
- capsule production
- hemin synthesis

hemin synthesis

The HACEK group of organisms are most commonly found as normal microbiota in:

- gastrointestinal tract
- skin
- mouth
- heart
- vaginal tract

Mouth

A person comes in with their newborn who has a repetitive cough with a "whooping" sound as you watch the baby gasp to breathe. You immediately suspect it is a case of pertussis. What special media would you culture it on for identification?

- Regan-Lowe
- Buffered charcoal yeast extract
- Loeffler
- CIN agar
- Chocolate

Regan-lowe

What is the typical transmission route for shigellosis?

- fecal:oral route between humans
- eating undercooked chicken
- via mosquitos
- drinking contaminated water
- respiratory droplets

fecal:oral route between humans

Most of the bacterial opportunistic pathogens are transmitted _____________

- fecal-oral
- tick transmission
- respiratory droplets

Fecal-oral

The following strain of Escherichia coli looks identical to Shigella on a Gram stain and biochemically. Symptoms can range from mild diarrhea to dysentery. What is unique to this strain is that it does NOT ferment lactose. What is the most likely etiologic agent?

- enteroinvasive
- enterohaemorrhagic
- enterotoxigenic
- enteroifudare

Enteroinvasive

The following bacteria has been associated with numerous outbreaks, especially in leafy greens and ground beef. Symptoms range from water diarrhea to dysentery, but if not treated can cause kidney failure. Due to its major virulence factor (stx1 and 2), it also has a very low infectious dose with only less than 100 CFU to cause disease. What is the most likely agent?

- Enterobacter cloacae
- Salmonella enterica
- Enterohaemorrhagic Escherichia coli (EHEC)
- Francisella tularensis

Enterohaemorrhagic Escherichia coli (EHEC)

Biochemical reactions of an organism are consistent with Shigella. A suspension is tested with antiserum and shows agglutination with group A antisera. The Shigella species is: (Hint: it is the second most commonly isolate species of this genus)
cattharalis

- enterocolitica
- paratyphi
- dysenteriae
- ducreyi

dysenteriae

A 49-yr old man with alcoholic cirrhosis developed septic shock due to Plesiomonas shigelloides. Normally the disease only causes a mild watery diarrhea, but considering the patient's medical condition before, it developed into something much worse. Which of the following do you think is the most likely way the patient acquired the infection
- a bite by an infected flea
- inhalation of respiratory droplets from an infected family member
- sexually acquired
- ingestion of undercooked Dojo nabe (loach fish-traditional Japanese dish)

ingestion of undercooked Dojo nabe (loach fish-traditional Japanese dish)

A neonatal case of meningitis was identified as coli O18:K1:H7. In this strain, H refers to the type of _______________

- fimbriae
- oligosaccharide
- capsule
- flagella

Flagella

What virulence factor is responsible for causing dysentery among EHEC strains?

- superantigen
- heat stable toxin (ST)
- shiga toxin
- flagella
- heat labile toxin (LT)

Shiga toxin

Pleisomonas shigelloides is a relatively new member of the Enterobacteriaceae family. What characteristic separates it from other members of the family?

- it is oxidative negative
- it is gram negative bacilli
- it can be found in the environment
- It does not ferment glucose

it does not ferment glucose

In November 2023, the CDC announced a new multistate outbreak of illnesses linked to cantaloupes resulting in 99 ill, 45 hospitalized and 2 dead so far. Many cases were found in Wisconsin and Minnesota. Below is a picture of a colony grown on HE agar (left) and MacConkey (right). What is the most likely etiologic agent responsible for this outbreak?

HE: Black convex colonies
MAC: Colorless colonies

- Escherichia coli
- Salmonella enterica
- Klebsiella oxytoca
- Shigella dysenteriae

Salmonella enterica

A 9-year old boy was brought to the hospital in Chiang Mai, Thailand with a low-grade fever, cough and sore throat for 5 days. Early on, he was diagnosed with pharyngitis and prescribed acetaminophen. On the 3rd day, fever declined and sore throat went away but the boy presented with worsening symptoms. His neck was swollen and began to have difficulty swallowing. History of the patient was that he had normal vaginal delivery and received BCG (tuberculosis vaccine) and Hepatitis B at birth but that was it. Sadly after the 16th day in the hospital, the patient body experienced systemic damage from a bacterial toxin and died. What is the most likely etiologic agent? (Hint: if the boy was updated on his vaccinations, this would not have happened most likely considering the vaccine is against the toxin).

- Bacillus anthracis
- Haemophilus influenza
- Neisseria meningitidis
- Corynebacterium diptheriae

Corynebacterium diptheriae

A 27-year old female patient with no previous history of psychiatric disorder appeared in the emergency room due to nonsense speech and self-harm. While in the ER, she bit the tip of her left thumb seriously (pic below). Several blood cultures were acquired after hospitalization at the psychiatric clinic after a malodorous discharge developed on the bite wound. After a lack of healing of the wound, it was further cultured and at the end of the 48h incubation, the following growth was evident on blood agar which also contained a bleach-like odor. Gram stain was performed and identified Gram negative thin bacilli. What is the most likely etiologic agent?

- Proteus mirabilis
- Francisella tularensis
- Eikenella corrodens
- Enterobacter agglomerans

Eikenella corrodens

A child was bitten on the arm by her sibling and the resulting wound grew a slender gram-negative bacilli that grew "pits" on blood agar, catalase negative, oxidase positive, no growth on TSI, and smelt like bleach. What is the most likely organism

- Pasteruella ureae
- Bordetella parapertussis
- Kingella kingae
- Eikenella corrodens
- Moraxella catarrhalis

Eikenella corrodens

A 54-year old Greek woman entered the emergency room with a high-spiking fever. She also complained of myalgia, sore throat and headache before. Multiple CT and MRI scans were performed on her brain revealing numerous lesions. These symptoms and brain results suggested endocarditis leading to cerebral embolization. Blood cultures were plated on chocolate agar and subcultured on a plate with two separate disks containing either X, V or both factor. Below are the results. What organism was it?

- Haemophilus parainfluenzae
- Serretia marscenes
- Aggregatibacter aphrophilus
- Haemophilus influenzae
- Haemophilus ducreyi

Haemophilus parainfluenzae

A 72-yr old male with lymphoma has a positive blood culture at 18h incubation. The organism is lactose fermenting, gram negative bacillus on MacConkey agar. Further testing shows: H2S+, indole +, citrate -, lysine decarboxylase +, phenylalanine deaminase (-) . What is the most likely etiologic agent?

- Klebsiella pneumoniae
- Edwardsiella tarda
- Providencia stuartii
- Enterobacter aerogenes
- Escherichia coli

Edwardsiella tarda

A sputum culture from an alcoholic seen in the ER grows a gray, mucoid, stringy colony on sheep blood agar. The isolate grows readily on MacConkey agar and forms a mucoid, dark pink colony. The colonies when analyzed further result in ONPG +, indole - , glucose +, oxidase - , citrate +, VP + , non-motile. The organisms is most likely:

- Legionella pneumophila
- Neisseria meningitidis
- Citrobacter freundii
- Klebsiella pneumoniae
- Enterobacter aerogenes

Klebsiella pneumoniae

This genus is known to be transmitted via contact with turtles and chickens, colonies appear clear on MacConkey, methyl red +, oxidase - and citrate +. What is the most likely genus?

- Citrobacter
- Escherichia
- Pleisomonas
- Aggregatibacter
- Salmonella

Salmonella

When trying to differentiate between the Enterobacteriaceae tribes, what test differentiates the Proteeae tribe from the rest?

- Mannitol fermentation
- phenylalanine deaminase
- Voges-Proskauer
- urease
- DNase

phenylalanine deaminase

A patient came in complaining of painful urination suggesting a urinary tract infection. His clinical history included kidney stones. When culturing out his urine, you recognized swarming motility, H2S production, urea positive, but indole negative. What is the most probable cause?

- Providencia alcalifaciens
- Proteus mirabilis
- Proteus vulgaris
- Escherichia coli
- Edwardsiella tarda

Proteus mirabilis

An organism causing an HIV patient chronic diarrhea and demonstrating the following characteristics: Gram negative bacilli, oxidase negative, indole +, methyl red +, H2S negative, citrate negative, positive on fermentation of glucose, lactose, and trehalose, as well as binding and stacking on Hep-2 cells. What is the most likely candidate?

- Citrobacter freundii
- EHEC
- EAEC
- Cronobacter sakazakii
- Proteus vulgaris

EAEC

A 55-year old Chinese female presented in the clinic with abdominal pain for 48h. Symptoms included vomiting, diarrhea, edema, fever, and melena (black tarry stools indicating blood). The patient was diagnosed with stage 5 chronic kidney disease in the past and was given peritoneal dialysis for renal replacement therapy. The following Gram stain results (A) were from a peritoneal dialysis fluid coming from the patient, which was identified as the etiologic agent. It was known to produce acid from glucose, maltose, fructose and sucrose, but not lactose. What is the most likely causative agent?

- Neisseria flavescens
- Kingella kingae
- Neisseria sicca
- Serretia liquefaciens

Neisseria sicca

A 5-yr old presented with an ear infection. An aspirate grew a colony after 48h on chocolate agar that appeared like in the picture. It also grew on blood agar and stained Gram negative diplococci. Further tests exhibited oxidase positive, catalase positive, and DNase positive

- Neisseria meningitidis
- Moraxella catarrhalis
- Nocardia brasiliensis
- Salmonella enterica
- Bacillus anthracis

Morxella catarrhalis

An 18-year old boy is admitted to the hospital with suspected meningitis. He is lethargic and presents with a rigid neck. He has not had most of the recommended vaccines from childhood to now. Gram stain of his CSF is presented below. The most likely etiologic agent is:

- Streptococcus agalactiae
- Haemophilus influenzae
- Neisseria meningitidis
- Listeria monocytogenes

Neisseria meningitidis

What is the one characteristic that doesn't match bacteria in the family Neisseriaceae?

Oxidase negative

Which of the following is NOT a typical test used to help classify nonfermenters?
MacConkey
catalase
oxidase
O-F glucose

Catalase

The following tests helps differentiate Proteus from other non-lactose fermenters in the family of Enterobacteriaceae. If an organisms is positive for the enzyme responsible for breaking down this substrate, ammonia is the by-product.

urea agar

XLD agar

CIN agar

Simmons citrate agar

Urea agar

MacConkey with sorbitol is specifically used to differentiate ___ O157:H7 from other E. coli strains. It shows up as a ___ colony on this media

MacConkey with sorbitol clear

A Chinese restaurant opened up near Milwaukee, WI. However, the business was very slow for the first few weeks. Considering the owners didn’t want to take any more financial losses, they kept the fried rice warm and continued to serve the same batch for weeks (yummy;). Their rational was that as long as the rice was warm, microbes wouldn’t grow on them. One evening 10 customers came in and ordered fried rice. Within 24 hours they were all vomiting profusely and reported to the hospital. The physician assumed it was an ingestion of an exotoxin of Bacillus cereus. He took a culture of the rice and handed it to you to perform a stain. What dye would you use as the primary stain to help in identifying this specific genus from most other genera? (Hint: what is unique about this genus? Focus on the stain that identifies what is unique to this genus)

crystal violet

malachite green

india ink

methylene blue

safranin

Malachite green

The following genus is a common laboratory contaminant due to its common presence in the environment
Salmonella
Haemophilus
Bacillus
Listeria

Bacillus

The following microorganism is responsible for causing a pseudomembrane in the posterior pharynx. On blood agar it appears as black colonies. What is the most likely etiologic agent?
Neisseria meningitidis
Cronobacter sakazakii
Shigella sonnei
Corynebacterium diptheriae

Corynebacterium diptheriae

Establishing the pathogenicity of a microorganism isolated from a child’s throat and identified as Corynebacterium diptheriae would depend upon:

a positive toxigenicity test

the morphological appearance under a Gram stain

the appearance of growth of Tinsdale tellurite agar

the type of hemolysis on blood agar

a positive toxigenicity test

The following etiologic agent is known to cause a black eschar if acquired cutaneously. It is also known to cause woolsorter's disease from humans known to have close contact to sheep.
Haemophilus aegyptius
Citrobacter freundii
Bacillus anthracis
Norcardia farcinica
Salmonella enterica

Bacillus anthracis

Which organism is considered bioterrorist threat?
Brucella
Haemophilus
Citrobacter
Hafnia

Brucella

People who are asymptomatic with Salmonella Typhi are typically known to harbor the bacteria silently in their ________________

spleen

stomach

pancreas

gall bladder

liver

Gall bladder

The following symptom is typical of typhoid fever
bubos
papules around umbilical region
arthritis
soft chancre

papules around umbilical region

A patient came in with an ulcer on her palm. After talking with her, you find out that she was trying to pick up a wild rabbit after feeding it and got bit by it. A blood sample was cultured on blood and chocolate agar with colonies only evident on chocolate after 24h. After a Gram stain, it appeared Gram negative coccobacilli demonstrating catalase and oxidase positive, though negative for urease activity. What is the most likely agent?
Francisella tularensis
Brucella melitensis
Ersipleothrix rhusiopathiae
Yersinia pestis
Edwardsiella tarda

Francisella tularensis

A 5-yr old presented with an ear infection. An aspirate grew a colony after 48h on chocolate agar that appeared like in the picture. It also grew on blood agar and stained Gram negative diplococci. Further tests exhibited oxidase positive, catalase positive, and DNase positive

Bacillus anthracis
Salmonella enterica
Neisseria meningitidis
Nocardia brasiliensis
Moraxella catarrhalis

Moraxella catarrhalis

A patient came into the clinic complaining of severe diarrhea that occurred ~ 20 times a day. The stools appeared with flocks of mucus that looked like rice. Identification of the organisms was oxidase, catalase, and nitrate reduction positive How did the patient most likely acquire the infection?
scratching infected flea feces into skin
drinking fecal contaminated water
tick bite
mosquito
scratch or wound that came into contact with contaminated water

drinking fecal contaminated water

The following is the most common isolate of otitis media. A culture of it would present as Gram negative diplococci, oxidase positive and nonmotile. What is the most likely etiologic agent?
Oligella urethralis
Moraxella catarrhalis
Anaplasma phagocytophilum
Treponema pallidum subspecies carateum

Moraxella catarrhalis

Salmonella can be identified due to its black pigment in its colony in ALL of the following media EXCEPT

cefsulodin-irgasan-novobiocin

hektoen enteric

salmonella-shigella agar

xylose-lysine-deoxycholate

cefsulodin-irgasan-novobiocin

Motility media is a typical media used to help differentiate members of the Enterobacterales group. Which of the following organisms would you NOT expect to be motile?
Enterobacter
Escherichia
Yersinia
Citrobacter

Yersinia