Microbiology Practice Test

A 28- year--old sexually active female presents with fever, pelvic pain, and a feeling of pelvic heaviness for the past week. Pelvic examination reveals a palpable left adnexal mass. Laparoscopy is then performed and the left fallopian tube is found to be indistinct and part of a circumscribed, 5-cm, red-tan mass involving the left ovary.
Swabs from the fallopian tube and ovary show gram-negative diplococci. Aerobic cultures on Thayer-Martin selective media but not the routine blood agar reveal oxidase positive colonies. Screening serology for syphilis is negative. The microbiologic agent most likely response for these findings is:

Which of the following is the most likely gram-negative curved bacilli responsible for a inflamed leg wound in a 42 year old man who has alcoholic liver disease, who 3 days was celebrating the 4th of July on the coast of Alabama?

Chancre of the vulva-- what stage of syphilis?

Asymptomatic neurosyphilis is suggested by...

A 65-year-old has an antibiotic induced
diarrhea, due to reduction in intestinal normal flora with overgrowth of this organism, has colitis with cramps, fecal leukocytes, and pseudomembranes.

Patient presents with condylomata lata -- what stage of syphilis?

What are the 4 different forms of neurosyphilis? and which is the most common?

Non-spore-forming, gram-positive rod-shaped bacterium; tumbling motility" in wet mounts of cerebrospinal fluid (CSF). Also the CSF was consistent with bacterial meningitis. What is it?

Which of the following is the vector for the
Borrelia burgdorferi?

A 60 year old female complained of "shooting" pains in the legs and enlargement of the knee joints for about 2 years. Her physician said that she had severe arthritis. The patient began to experience difficulty walking in the dark and urinary incontinence and sought other medical advice.
The neurologic exam demonstrated Argyll Robertson pupils and radiographs of the knees were consistent with arthritic "Charcot type" joints a neuropathic arthritis. The patellar and ankle reflexes were absent and there was loss of vibratory and position sense in the lower extremity. The patient's ataxia was evident as she walked with a broad-based gait. She was very nervous when asked to walk or stand with her eyes closed and demonstrated the Romberg sign

A 19 -year –old gravida 2, para 1 presents at her first prenatal visit complaining of a rash, hair loss, and spots on her tongue.
Physical examination shows a maculopapular rash on her trunk and extremities, including her palms and soles.
Close-up view of keratotic lesions on the palms of this patient’s hands due to a secondary syphilitic infection. Syphilis is a complex sexually transmitted disease (STD) caused by the bacterium Treponema pallidum

RPR and MHA-TP are positive (non-treponemal and treponemal tests).
Although vague about the description, she remembers a single painless, indurate papule on the vulva that quickly ulcerated with a fairly clean base.
A specimen is not submitted. The patient is treated with the recommended antibiotic, penicillin.
What are the most likely findings on a gram stain of the initial papule?

Sexually active female with signs and symptoms of syphilis is this presentation.
Primary lesion goes unnoticed (common in women), so not available for visual examination.
Serology is essential. If she had active syphilis what would you expect on serology?

A 30 yo man returns from vacationing on eastern Long Island in the Hamptons and presents to the clinic with sore throat, neck stiffness, and an erythematous circular rash on his right side. The rash is warm, but not painful or itchy. The rash started as a papule that expanded over several days, with central clearing, to form an annular, erythematous patch…
Case: red expanding borders and a clearing center
He spent his time on the beach; and did not recall tick or flea, or insect bites.
Low grade fever and malaise developed several days before the rash.

A diagnosis was made based on the skin lesion. What do you suspect the the specimen is?

A healthy 20 year-old male has a mild pharyngitis followed a few days later by the sudden onset of a severe headache. Physical examination reveals nuchal rigidity. His vital signs reveal a temperature of 38.8oC, respiration of 26/min, pulse of 98/min, and blood pressure of 95/45 mm Hg.
Clinical presentation
Meningitis following pharyngitis, rapid onset, in young children and adults limits the differential diagnosis

Examination of the CSF shows neutrophils, low glucose, high protein, and gram- negative diplococci. India ink stain is negative.
The infectious agent most likely to have caused this clinical presentation is

A 34-year-old female presents to the ER complaining
of muscle weakness, and diplopia. She had some of
grandma’s green beans the night before as well as
chicken and rice. The most likely cause of her
symptoms is:

A 65 year old female has a 3-cm, solitary, left upper lobe mass discovered by chest x-rays. The mass is removed at thoracotomy by wedge resection.
The microscopic appearance shows granulomas with central caseating necrosis, Langhans giant cells, and numerous mononuclear cells. Review image from lung, shows alveoli. Malignant infiltrates are not identified. What is the most likely diagnosis for this patient?

A 54-year-old Vietnamese lady who spent 4 years in a Pacific refugee camp before coming to the U.S. now suffers from back pain, weight loss, and night sweats.
X-rays show vertebral destruction (lytic). Examination of the bone tissue shows soft, friable “cheesy material.”
Bone biopsies show granulomas with caseous necrosis
Gram stain is non-diagnostic (gram stained organisms are not seen).
The Ziehl-Neelson acid-fast stain shows acid-fast bacilli.

The bone material is negative for malignant infiltrates.
The bone material is submitted for routine aerobic and anaerobic cultures, prolonged incubation in a mycobacterial Lowenstein-Jensen media, rapid mycobacterial broth, and fungal cultures.
Based on the acid-fast stain results, treatment is initiated; the culture results confirmed the diagnosis 8 weeks later.

What is the most likely diagnosis for this patient?

Patient has an upper respiratory tract illness characterized by sore throat, low-grade fever, and an adherent membrane of the tonsils(s), pharynx, and/or nose
Which pathogen would have a "drumstick" like appearance under the microscope?

An unvaccinated boy recently arrived from an Eastern European country, presents with sore throat with dirty white pharyngeal exudates (pseudomembranes), cervical lymph nodes, and an irregular heart rate. Carefully obtained swabs of the exudate show rare gram positives non-spore forming bacilli (gram stain). What is the most likely organism?

How is Staphylococcus aureus differentiated from Staphylococcus epidermidis or other Staphylococcus spp?

An 89-year-old man presented with weight loss of 38 lbs over the past 4 years.  He appeared extremely thin and was very weak.  His BP was 123/72 and his temperature was 37.3.  PPD was negative . He died 2 days after admission to the hospital.  At autopsy his lungs, spleen (shown below), adrenals, and kidneys were filled with numerous small granulomas.  M. tuberculosis was cultured from his lungs

How do you explain his negative PPD?

Acid fast stain from the lung of a 27-year-old man who has AIDS. Mycobacterium avium complex (MAC) with acid fast stain often has the characteristic appearance shown here with numerous mycobacteria filling macrophages. Such macrophages may be distributed diffusely or in clusters.

Acid Fast Stain from the Lungs of a 27-year-old Man most likely represents?

Currant Jelly: Currants are small, rounded fruits with smooth skin.  They can be red, yellow, green, or black in color; used like raisins. R: “Currant-jelly” sputum...Which of the following respiratory pathogen is the most likely cause of this disorder?

A 54 –yo- man was admitted to the hospital in January with fever, shortness of breath, productive cough, and chest pain.
He was a chain smoker (2 packs/day), and had no known underlying chronic diseases.
He had not taken his current flu vaccine.
Fifteen (15) days PTA he experienced sudden onset of fever/chills/sore throat/arthralgias. His symptoms resolved over a week, before the onset of these current symptoms.

Work-up
T: 39.4C° (103°F)
Respiratory distress, decreased breath sounds and rales at left base
WBC count : 16,700/µL (5-10,000) with 55% PMNs (segmented neutrophils), 16% band neutrophils, 22% lymphocytes
Neutrophilic leukocytosis
CXR: infiltrates in the left lower lobe
Gram stain of pustular exudate: Gram-positive, cluster-forming cocci non-motile, non spore-forming facultative anaerobe

A 43-year-old man presented with painful ulcers on his penis. He first noted painful lumps (papules) which then became “boils” (pustules) which ulcerated after about 2 weeks. The ulcers had irregular borders, were beefy red in appearance, and were painful.
His inguinal lymph nodes were unilaterally enlarged and painful upon palpation. The skin appeared thin over one lymph node and it appeared that it might rupture. Gram stain showed single gram negative cocci. The patient was not febrile. The chancroid and unilateral painful purulent inguinal lymph nodes is due to

A family had a BBQ cookout with burgers ( that was kinda pink inside), hotdogs, and lemonade. Little Jimmy started to have bloody diarrhea. Stool cultures (special media) are positive for gram negative bacilli; glucose and lactose fermenters (EMB or MAC); catalase positive and oxidase negative. The EMB has a purple sheen (very characteristic).

Which of the following pathogen is the most likely cause of this disorder?

What are the biologic properties that directly contribute to a necrotizing pneumonia?

A 35-yr-old healthy male presented with abdominal pain and blurred vision 12 hr after ingesting a "bad" potato. During his meal, he had taken a mouthful of a foil-wrapped baked potato and found it to be foul tasting and spat it out. The potato was immediately disposed of.
He felt slightly nauseated but finished his meal.
Approximately 12 hr later he awoke with abdominal pain and blurred vision.
During the next 17 hr, the patient demonstrated a gradual descending paralysis which ultimately resulted in no cranial nerve function and 0/5 strength in all extremities. Sensation was intact. The patient required intubation and mechanical ventilation.
His blood count, biochemical profile, computerized tomography and magnetic resonance imaging of the head were normal. A lumbar puncture revealed no abnormalities.

What are the expected culture results?

A 21- year- old man presents to the ER in shock, febrile, tachycardiac, tachypneic , and hypotensive
He has a productive cough with blood tinged sputum
Gram stain of the sputum has Gram positive diplococci (satisfactory specimen with few squamous cells and numerous lower respiratory tract macrophages)
Chest X-ray shows localized infiltrates in the left lower lobe
Which of the following respiratory organisms
is the most likely cause of the infection?

Which of the following organisms is one of the most common causes of localized pneumonia in patients presenting with fever and productive cough with blood tinged sputum, Gram stain of the sputum has Gram-positive diplococci that are catalase negative, and the inflammatory response is suppurative

What causes a watery non-inflammatory diarrhea with dehydration due to large fluid loss (speckled with flakes of mucus and epithelial cells ) and is an oxidase positive, gram-negative curved bacillus requiring special media?

A 47-year old man with a history of sickle cell disease has had numerous hospitalizations requiring the placement of IV lines. The patient develops right arm swelling and discomfort at an IV site. His temperature increases to 40.1 C. Blood cultures for aerobic and anaerobic incubation are taken, and colonies of gram-positive cocci are isolated on the routine aerobic media. The isolated organism is catalase positive, coagulase negative, and non-hemolytic on sheep blood agar media. Which of the following organisms is most likely cause of this patient’s symptoms?

A 7-year-old boy presents to his pediatrician because his mother noticed dark urine. On analysis, the urine is dark due to numerous red blood cells.
On questioning the mother, it is revealed that boy had a severe sore throat with fever, fatigue, and “neck glands” several weeks ago that was left untreated. The mother forgot to buy the antibiotics. The laboratory reports from the previous visit indicate neutrophilic leukocytosis. A throat swab from a tonsillar exudate was submitted for aerobic culture and grew gram-positive, beta hemolytic, catalase negative cocci.
Presently, the physical examination reveals hypertension and mild generalized edema edema = low onconic pressure. The physician suspects glomerular disease with hematuria and proteinuria.
The patient’s kidney disease followed an acute case of pharyngitis. Which of the following respiratory pathogens is the mostly microorganism responsible for this child illness?

Of the bacteria listed which one can cause a diarrhea after eating raw shellfish due to oxidase positive, gram-negative curved bacilli that require a special media?

A 32-year old woman with increased frequency of urination, suprapubic pain, and dysuria for the past 3 days presents to her PCP. She has no fever, nausea or vomiting. A Gram stain reveals gram-negative rods.

Which of the following is the most likely pathogen?

A 1-week old girl with symptoms of vomiting and anorexia has a temperature of 102° F. A bulging fontanel is noted. The baby was delivered vaginally. A diagnosis of neonatal meningitis is made. Gram stain of centrifuged cerebrospinal fluid sediment shows gram-positive cocci in chains. Cultures are submitted in and aerobic and anaerobic conditions on blood and special chocolate media. The isolated colonies show beta hemolysis and negative catalase function (and are bacitracin resistant)

What is the most likely cause of this infection?

A 2-year-old child, who has recently recovered from a “sore throat”, has been lethargic, irritable and anorexic for the last three days.
She is now febrile and occasionally tugs her right ear lobe.
On physical examination, she appears to be a well developed, well nourished (13 kg) female in moderate distress. Her vital signs (VS): T 39.4°C.(102.92 degree Fahrenheit)
Otoscopic examination shows the right tympanic membrane to be hyperemic and bulging, with almost no movement on pneumatic application. The left tympanic membrane is hyperemic, but no effusion. Her lungs are clear.
Blood is drawn for a CBC.
The diagnosis of otitis media is contemplated. Which of the following is the most likely pathogen in this case?

A 26-year-old male with AIDS presents with painful bloody diarrhea.
Stool culture on MacConkey selective medium and subsequent analyses reveals predominantly a gram -negative facultative anaerobic rod, which is oxidase negative, lactose negative, H2S negative and non-motile.
Which of the following is the most likely cause of this infection?

A 68-year-old homeless alcoholic is taken to the emergency room with suspected seizure activity. The examination reveals spastic paralysis in the jaw area (lockjaw).
By the time he enters the hospital he has developed rigid back spasms and a stiff and hyperextended neck.

The aerobic wound culture, aerobic and anaerobic blood cultures are no growth. The fungus culture is no growth.
The ANAEROBIC wound culture grows gram-positive spore forming bacilli.

The anaerobic wound culture grows gram-positive spore forming bacilli. often with endospore at one end (“drumstick”)

What is the most likely organism?

56 year old man to OPERATING ROOM --for colon CA; the lesion is successfully resected; 2 days later he developed pain at the surgical site
Within several hrs, local edema, tenderness developed at the wound, as well as a thin, brownish discharge
The surgical wound site had discoloration of the skin, hemorrhagic bullae, serosanguineous discharge from the infected wound; extensive gas in the tissue.
Gram stain of the wound aspirate: pleomorphic population including multiple thin gram negative bacilli, gram positive cocci and gram positive bacilli in chains contained within a background of polymorphonuclear cells. Aerobic culture: no growth and Anaerobic growth: positive growth

What is the most likely organism?

You are seeing a 25-year-old woman in her 10th week of pregnancy with a 2-day history of mild fever, loose stools, and vomiting. She reports that she has not eaten unusual foods in the past week. You wonder whether this patient might have listeriosis. What was the most common food vehicle for listeriosis?

Meningitis developed in a female infant born after 36 weeks of gestation from a 29 years old mother, was presented.
The newborn was hospitalized in intensive care unit because of low birth weight (1740 g) and prematurity. Due to the worsening of her general condition (feedings difficulty, tachypnea, high fever and bulging fontanel) on the 11th day, blood and cerebrospinal fluid (CSF) cultures were done. CSF culture yielded catalase positive, oxidase negative, gram-positive bacilli on the 4th day of cultivation. The isolate was identified as

A 3-week old baby boy was brought to the ER with a 24-hr history of fever, poor eating, irritability, and a seizure that occurred just before arrival to the ER. He was born pre-term with very low birth weight after a normal vaginal delivery
He was febrile (T: 38.2°C/101°F) with nuchal rigidity (neck stiffness that prevents flexion/triggers pain and muscle spasms)

How do you work-up this case?
Check CSF (2) tubes,
1 for chemistry ( to know protein and glucose).
2. for Cytology (lymphocytes, neutrophils, tumor cells)
2. Do Culture to figure out the organism

What specimen?
CSF:
WBC: 2,340 (<32 cells/mm3) with 89% PMN think bacteria
Protein 180 mg/dL (15-45 mg/dL): increased disrupted blood brain barrier
Glucose 15 mg/dl (40-70 mg/dL); decreased fermented glucose
Gram Stain: Gram positive cocci in chains
Suggestive of bacterial meningitis, not viral
Which of the following organisms is most likely cause of this patient’s
symptoms and why?

Which of the following tests is preferred for the diagnostic evaluation of C. difficile Infection (CDI)?

Cutaneous anthrax is due to

A patient has watery diarrhea and vomiting after traveling to Thailand. Which of the following is the most likely?

Which of the following are the predominant species in the colon?

Streptococcus mutans is the primary bacterium involved in

Pseudomonas aeruginosa

Which of the following genus has species that are gram-positive anaerobic spore forming bacilli capable of invading and contaminating wounds to induce CNS spasms; cause food poisoning and botulism; produce an antibiotic induced diarrhea, or tissue infection and gas gangrene?

A 4-year-old boy is admitted to the hospital emergency room with severe abdominal pain. A stool examination reveals fecal leukocytes and rectal exam shows “occult” blood in the stool.
Culture of the stool is diagnostic. It reveals a Gram-negative rod that is a lactose non-fermenting on MacConkey agar (and EMB). The specialized selective culture media is needed to inhibit the gram-positive, normal fecal flora and is also a differential media that divides colonies into lactose fermenters and non-lactose fermenters.
The microbe is non-motile, and oxidase negative.
Culture of the stool is diagnostic. It reveals a Gram-negative rod that is a lactose non-fermenting on MacConkey agar (and EMB).
Which of the following is the most likely genus for the offending pathogen?

What gram negative organism
is responsible for
rapidly enlarging lymph nodes (buboes)
Fever
Conjunctivitis
Sepsis
Pulmonary emboli and pneumonic plague
DIC, hemorrhage (black discoloration under the skin) and shock
High fatality

A 68-year-old homeless alcoholic is taken to the emergency room with suspected seizure activity. The examination reveals spastic paralysis in the jaw area (lockjaw). By the time he enters the hospital he has developed rigid back spasms (opisthotonic posturing) and a stiff and hyperextended neck. His feet show obvious gangrene with necrotic, blackened areas and draining ulcers on both feet. Gas production was not present.
Blood and foot wound cultures were taken and submitted for aerobic bacteria, anaerobic bacteria, and fungal cultures. The patient was given supportive treatment to prevent paralysis of the throat and respiratory muscles. The aerobic wound culture, aerobic (too much oxygen) and anaerobic blood cultures (not in blood yet) were no growth. The fungus culture was no growth. The anaerobic wound culture grew gram-positive spore forming bacilli. What is the most likely organism?

While repairing a fence at his ranch, a 36-year-old lady cuts the skin over her shin. The wound heals without any complications. Several days later, she develops muscle spasms of her face, legs, and arms. These spasms become progressive to severe contractions. Which of the following is prophylactic for this disease?

Gram-negative rods that ferment glucose, are oxidase negative, and catalase positive bacteria are in the family-Enterbacteriaceae (excludes Vibrio and Campylobacter).
Which genus in this family are non-motile lactose non-fermenter?
Consider this case: Which of the following is the most likely genus for the offending pathogen? The offending pathogen belongs to the genus

Select the answer that understanding of what the Ghon Complex is

Three family members present to the emergency room with sudden onset of abdominal cramps, nausea and vomiting, watery diarrhea (no blood), up to 1 liter (quart) per hour , the diarrhea has a "rice water“ appearance, in which the stool looks like water with flecks of rice and it has a "fishy" odor; image below profuse watery diarrhea: rice-water stool.
Each person has dehydration, rapid heart rate, dry skin, dry mucus membranes, and low urine output. They just returned from New Orleans where they ate raw oysters and sushi
from the Gulf of Mexico.
The isolate is an oxidase positive, gram-negative curved bacillus requiring special media. It ferments glucose, but not lactose. Which of the following is the most likely enteric pathogen?

An 18-year-old sexually active female presents to the clinic for work-up of diarrhea nd abdominal discomfort. The symptoms started 1 week prior to the visit. Two days prior to the visit, she noted intermittent, crampy, periumbilical abdominal pain.
P.E. is notable for left lower abdominal tenderness.
Pregnancy Test is negative (always consider in reproductive aged females)
Fecal examination demonstrates greenish, watery stool that is negative for occult blood; negative for ova & parasites (O & P)
WBCs are present. Fecal cultures are submitted…
MacConkey selective (or EMB) media is used to inhibit the gram- positive bacteria.
Special antibiotic containing media is incubated at microaerophilic conditions, 42º C (rather than 37º C). The causative bacteria grows on the selective media at 42º C.
Gram stain of the isolated colonies of bacteria revealed slightly curved, gram -negative rods. The bacilli are oxidase positive.
Which of the following pathogen is the most likely cause of this disorder?

A bulging fontanel is noted.
This is most likely a central nervous system pathogen and secondary to delivery complications, specifically early rupture of fetal membranes. The option list has pathogens associated with meningitis. Cultures are submitted to isolate aerobes, as routine and with enhanced CO2. CSF ( a sterile body fluid) is inoculated on blood agar, chocolate agar, and Thayer Martin agar ( a special media for fastidious organisms) .
At this time, viral and/or fungal are not submitted

What is the most likely cause of this infection?

A 14 – year old boy is brought to the emergency department with a single gunshot wound in the abdominal left lower quadrant.
The patient does well for 5 days following surgery. On the 6th day, however his temperature rises to 102oF and he complains of abdominal pain, particularly in the left lower quadrant and generalized rebound tenderness.
Microscopic examination of a gram stained sample of pus drained from this patient’s (abdominal) abscess shows polymorphonuclear leukocytes and bacteria, including large pink rods (organism #1) and pale staining pink rods (organism #2), some of which have pointy ends and some of which have irregular shapes.
When a sample of this drained abscess material is aseptically cultured, several different types of colonies are observed. Some of the colonies grow only under anaerobic conditions; at least one colony grows under both aerobic and anaerobic conditions. Which of the following is the pathogen?

A 25-year-old female medical student reports that she had lunch at restaurant presents to you in the afternoon with abdominal cramps and nausea and vomiting. She had chicken, fried rice, and sushi. Culture and gram stain reveal gram- positive aerobic rods. Which of the following is the most likely cause of this infection?

A 57 year old woman with a history of
kidney stones and recurrent urinary tract
infections presents with fever, chills,
leukocytosis, and cloudy urine that has a
alkaline pH of 8.2 (expect acidic pH ~6; range
4.5 – 8.0.)

Urine culture grows a
lactose negative,
urease positive, gram-
negative rod. It has
a characteristic Which
of the following
organisms is most likely
cause for her infection?

Which of the following genus has gram-positive aerobic spore forming bacilli capable of causing several different types of disorders-ulcerated skin lesions, virulent pneumonia, and food poisoning?

1976 American Legion ceongention outbreak of pnx occurred
Pt ha da high fever, confusion, non-productive cough, and HA
The etiologic agent was identified as an aerobic motile, and nutritionally fastidious organism pleomorphic gram negative rods

The organism was isolated in the air conditioning units

Which organism was the culprit?

A 23 yo female acute pharyngitis , throat swab for routine bact cultures on special medial for fastidious pathogens , club shaped gram + rod, no known childhood immunization, recent exposure to Upper respiratory droplets from a child with pseudomembranous infecition

What was the likely organism?

Which of the following pathogen is responsible for pnx, occult febrile bacteremia, meningitis, epiglottis, septic arthritis , cellulitis, otitis media?
It is transmitted by direct contact with resp droplets from a nasopharynx carrier or a sick patient. Due to routine use of a vaccine since 1990, the incidence of the vaccine disease in infants and young children has decreased

A man with known COPD in the hospital for elective surgery, during the post oo period he develops a fever and productive cough of thick tenacious and blood tingled (current jelly) sputum

PE ( new onset): fever, crackles, at right lung base
Lab: neutrophilic leukocytosis
XRAY: right upper lobe infiltrates with cavitary lesion
Sputum is collected 3 times
Sputum, satisfactory for evaluation. Gram negative bacillary organisms and alveolar histocytoces

Diagnosis?

45-year-old alcoholic man presents with cough, shortness of breath, and fever.
Chest x-ray shows lobar consolidation.
Gram stain of the sputum shows gram-negative rods.
Culture reveals oxidase negative, catalase positive, glucose and lactose fermenting gram-negative rods.

Which of the following respiratory pathogen is the most likely cause of this disorder?

A 3 -week old male infant has bulging fontanelles, increased respiratory rate, and neutrophilic leukocytosis.
Based on the CSF findings, bacterial meningitis is suspected. CSF findings suggests
bacterial meningitis before
culture results.
Color: Cloudy (not clear)
Protein: Increased (Impaired BBB)
Glucose: Decreased, catabolized
LDH: Elevated
Cells: Neutrophils more than Lymphs

CSF findings suggests
bacterial meningitis before
culture results.
Color: Cloudy (not clear)
Protein: Increased (Impaired BBB)
Glucose: Decreased, catabolized
LDH: Elevated
Cells: Neutrophils more than Lymphs

Gram stain of the CSF sediment reveals gram -negative bacilli.
Aerobic culture has Gram-negative rods that ferment glucose and lactose, are catalase negative, and oxidase negative.

Which of the following pathogen is the most likely cause of this disorder?

A 53-year-old patient in the burn unit develops cellulites and sepsis. He has sweet-smelling wounds on his right arm and blue –green wounds on his left arm. Blood cultures were obtained. The cultures were positive for gram- negative motile rods in the aerobic bottles.
Identified on the basis of its Gram morphology, its biochemical profile, its fruity odor (characteristic sweet grape like odor), elaboration of green pigment and its ability to grow at 42°C.
Which of the following pathogen is the most likely cause of this disorder?

Test for heterophile antibodies

Ulcer with Chlamydia Trach lymph nodes, uncommon STD, unilateral swelling, gram stain identified

Likely organism?

he pathogenesis of this gram negative bacteria infections is not completely understood, although the presence of the type b polysaccharide capsule is known to be the major factor in virulence.
Encapsulated organisms can penetrate the epithelium of the nasopharynx and invade the blood capillaries directly. Their capsule allows them to resist phagocytosis and complement-mediated lysis in the non immune host. Non-typeable (non encapsulated) strains are less invasive tend to colonize the upper respiratory tract, but they are apparently able to induce an inflammatory response that causes disease (otitis media, sinusitis).
Vaccination with type b polysaccharide is effective in preventing infection, and several vaccines are now available for routine use. It is

Human infection usually presents as a painful redness and swelling of the skin following animal bites or scratches, usually from cats and dogs.

Name the most likely organism.

A 4 –year- old unvaccinated child and a 65- year- old,
whose vaccination acquired immunity has waned, have
a dry hacking cough and lymphocytosis due to gram
negative bacterial infection. This is not croup due to the virus parainfluenza.

Most likely organism?

Which 4 organisms require special growth (Fastidious)?

A 28 year old female was at an outdoor picnic feasting her eyes out eating colslaw, ham, and potatoes salad.
A few hours later she had N/V

What is the likely organism??

Which presents with clear discharge and purulent discharge? (in that order)

Necrotizing pneumonia is secondary to

A 25-year-old female medical student reports
that she had lunch at a Chinese restaurant
presents to you in the afternoon with
abdominal cramps and nausea and vomiting.
Culture and gram stain reveal gram- positive
aerobic spore forming rods.
Which of the following is the most likely cause
of this infection?

Gram – pleomorphic rods, “clue cells”

Three weeks after a meal at a local café in Austin Texas, a 23-year-old male develops malaise. He has mild scleral icterus, fatigue, and loss of appetite. His symptoms abate over 3 weeks. On returning to the café, he finds that the city’s Health Department has closed it. Laboratory findings for this patient are most likely to show that he has

What is the significance of the presence of
Hepatitis B surface Antigen (HBsAg) in a
43-year old woman with jaundice?

A specimen for a viral culture is collected on Friday and must be held for processing until the following Monday. (Note: viruses are obligate intracellular parasite and is not free living, so will need support to remain viable)

Which of the following is the optimal storage?

59 year old heart transplant patient
Steroids for episodes of acute rejection
Malaise, fatigue, fever, and dyspnea
Anemia and leukopenia

Most likely organism?

What is the most useful method in diagnosing rabies?