THE END: MICRO

Place the steps of the HIV cycle in order. (1) provirus delivered to nucleus (2) tRNA primes synthesis of complementary strand DNA copy (3) DS DNA provirus produced (4) reverse transcriptase enzymes degrades the +RNA strand

2-4-3-1

The epidemiology of which of the following viruses would be resistant to drying detergents and gi tract secretions and even mild chlorine treatment

Adenovirus

Influenza pandemics occur because

Antigenic shifts in the viral hemagglutinin

Two workers on a small ranch discovered sick and dying cattle in the field. One worker developed lesions on his hands which formed into black eschars. A stained specimen from a lesion showed large rods in chains

Bacillus anthracis

The asexual budding structures observed on the classic yeast forms of Candida Albicans are called

Blastoconidia

Which property is associated with HSV

Escapes antibody neutralization and clearance by cell to cell spread and by going into latency in neurons

Spastic paralysis is characteristic of a disease caused by

Clostridium tetani

Which of the following is a selective and differential media used for isolation of staph

Mannitol salt agar

Dermatinacious fungi are:

Dark in color due to the production of melanin

The natural host for ebola is believed to be which of the following

Fruit bat

What lab test could be done to confirm diagnosis of EBV induced infectious mononucleosis and distinguish it from CMV infection

Heterophile antibody detection

Each of the following statements concerning Neisseria meningitides is correct except

It produces an exotoxin that stimulates adenylate cyclase

The etiologic agent of Pontiac fever is

Legionella pneumophilia

Which of the following is the test of choice for diagnosing chlamydia trachomatis infection

Nucleic acid amplification tests

The clinical course of syphilis evolves through three phases prior to latency in the untreated host what is the characteristic feature of the initial or primary phase of syphilis

One or more painless skin lesions at the site where spirochetes penetrated

Each of the following viruses possesses an outer envelope except

Polio virus

Negri bodies are neuronal intracytoplasmic inclusions containing nucelocapsids

Rabies virus

Each of the following statements concerning staphylococcus is correct except

Scaled skin syndrome caused by staph aureus is due to enzymatic degradation of epidermal desmosomes by catalase

Which of he following foods is most likely the source of listeria monocytogenes

Soft cheese made with unpasteurized milk

Paracoccidioides brasiliensis has been isolated?

Soil from subtropical rain forests

A 22 year old male returned with pneumonia from a camping trip on the Mississippi river. Fungus sputum culture at 25 degrees Celsius grew white to brownish colonies composed of septate hyphae, cylindric condispores bearing simple round pear shaped candida. The candida were smooth walled and 2 to 10 um in diameter. To check for dimorphism the hypate was cultured on fungal agar at 37 C. What is the most probable microscopic morphology at 37 C?

Yeast like cells (8 to 15 um in diameter), appearing thick walled with broad based buds.

On a summer day in august an 18 yr old man was taken to the emergency department of a local hospital because pf a 2 day history of fever weakness and pain in his left groin and diarrhea. The groin pain was so severe that he walked with a limp. He also has small rashes on his leg. The patient lived in flagstaff Arizona the patient was admitted blood culture and lymph node aspirate cultures were obtained the following day cultures of blood samples were positive for growth of an organism based n the clinical description what is the most likely etiology of his clinical disease

Yersinia pestis

Which of the following dermatophytes produces only macroconidia:

Epidermophyton floccosum

All of the following are characteristics of human pathogens in the genus Brucella except

Fermentation of glucose

The most common recognized manifestation of parvovirus b19 infection in children is

Fifth disease

An outbreak of Marburg hermorrhagic fever in the Democratic Republic of Congo results in >150 cases, with a fatality rate over 50%. The etiologic agent of this disease is classified as a:

Filovirus

The primary neutralizing antigen of the influenza a virus is the

Hemagglutinin

What is the target cell receptor for HSV

Heparin sulfate a proteoglycan found on the outside of many cell types

Each of the following viruses is likely to establish a chronic or latent infection except

Hepatitis A virus

Which of the following statements is the most accurate in regards to West Nile virus?

Most infections are asymptomatic, but the only we are at risk for encephalitis

Each of the following statements concerning coccidiodes immitis is correct except

Most of the infections are symptomatic and require treatment

The natural epidemiology of strep agglactiae dictates special procedures to be done to screen pregnant women for risk of neonatal disease as well as post partum sepsis. Which of the following statements best describes the special procedure?

Vaginal and rectal swab sample collection at 35-37 wks of gestation and inoculation into lim broth

A 20 yr old patient comes to the homeless clinic with a skin abscess on the right arm. A swab from the intact skin overlying this abscess grows coagulase negative staphylococci. An aspirate sterilely with a needle and syringe grows staph aureus. About these two organisms in the patient you can say

The staph aureus is a pathogen and the coagulase negative staph is not

A 25 yr old woman has a 4yr old son who is now recovering from group A strep pharyngitis. Out of curiosity, the pediatrician does a throat culture on the mother which is positive for group A strep even though she doesn't have a sore throat. The pediatrician also does an ASO titer on the mother which is negative. At this point we would say that she:

A carrier

A 23 yr old who works in a day care center experiences the sudden onset of fever fatigue nausea and stomach pain and loss of appetite. Jaundice is observed 5 days later and the diagnosis of hepatitis is made. Transmission of the virus causing these clinical manifestations is initiated by which viral characteristics

Ability to withstand acids and detergents and be transmitted by fecal oral route

An important characteristic of mycobacterium is that they are

Acid fast

Which of the following organisms is associated with hospital acquired infections, can be present on healthy skin has a gram stain morphology that is a plump cocci-bacilli that can mimic diplococci and are oxidase negative

Acinetobacter baumannii

A patient isolate of staph aureus is found to resistant to oxacillin. Which mechanism is most likely causing this resistance

Acquisition of a gene (mecA) and production of a novel penicillin binding protein

There was an outbreak of illness among approx. 40% of new recruits at an army boot camp facility in September. It was characterized by sore throat conjunctivitis and fever. No common bacteria were isolated from the recruits but a similar virus was isolated from the throat and conjunctiva and stools of seven individuals. Lab tests showed it to be solvent resistant dna virus the clinical picture, epidemiology and viral composition most likely places this virus as a member of which group

Adenovirus

Which of the following viruses is known to cause swimming pool conjunctivitis

Adenovirus

A 7 yr old develops a rash that spreads over the body and papules vesicles pustules and crusted lesions are observed in different places on the body what is the most likely mechanism of this infection

Aerosol

Each of the following statements concerning Candida albicans is correct EXCEPT:

Albicans is transmitted primarily by respiratory aerosols

Dermatophyte infection are usually limited to the nails, the hair, and the striatum corneum of the skin because:

All the organisms obtain nutrients from kertain which is a component of these sites

Which one of the following statements concerning mumps is correct

Although salivary glands are the most obvious cites of infection the testes, ovaries, and pancreas can be involved as well

Your patient is a 15 yr old boy with migratory polyarthritis fever and a new cardiac murmur. You make a clinical diagnosis of rheumatic fever which of the following lab results is most likely to be found in this patient

An anti streptolysin O (ASO test) assay is positive at this time

Which one of the following modes of pathogenesis is most compatible with a diagnosis of rheumatic fever

Bacterial antigens induce antibodies that cross react with joint and heart tissue

Which organism is an anaerobic gram negative rod that is an important cause of peritonitis

Bacteriodes fragillis

Your patient is a 70 yr old man who underwent bowel surgery for colon cancer 3 days ago. He now has a fever and abdominal pain. You are concerned that he may have peritonitis which one of the following pairs of organisms is most likely to be the cause

Bacteriodes fragillis and klebsiellea pneumoniae

When grown on CHROMagar Candida, colonies of C. tropicalis appear:

As dark blue to metallic-blue colonies

Choose the organism that best fits the clinical and diagnostic criteria described below. Clinical findings: A 60-year-old man with a history of tuberculosis now has a productive cough and bloody sputum. Chest x-ray reveals a round of opaque mass with a cavity in his upper lobe. Laboratory findings: culture of the sputum grew an organism with septate hyphae with low-angle (acute) branching.

Aspergillius species

The most reliable diagnostic test for clostridium deficile disease is

Assay of stool for presence of toxin

Based on the Lancefield antigen classification system streptococcus agglactiae organisms are classified as which group

B

Which Lancefield group of streptococci colonize the upper respiratory, gastrointestinal, and genitourinary tract of women and may be transmitted to their infants in utero during parturition or post partum period resulting in early onset or late onset meningitis pneumonia and bacteremia in neonates

B

Five hours after eating at a restaurant four of five roommates experience nausea, vomiting, and severe abdominal cramps. One of the first affected also has diarrhea. The symptoms resolve in a day. The most likely cause of this food poisoning is

B. cereus

Choose the organism that best fits the clinical and diagnostic criteria described below. Clinical findings: Uncomplicated pulmonary disease and 56-year-old Ohio male, Discovered by radiography during it periodic Insurance examination; Pulmonary infiltrates With no apparent distress. Laboratory findings: at 25 degrees, septate hyphae with round conidia; at 37 degrees, thick walled yeasts, some with broad-based bud, 8 to 15um in diameter

Blastomyces dermatitdis

A month after a vacation in the forest of the eastern shore of Maryland a 22 yr old male develops onset of fever muscle aches and headaches. Two weeks later a single spreading rash with a pale halo surrounding a brighter central area develops on the back off his thigh the clinical vignette is most commonly associated with which bacteria

Borellia burgdogeri

The etiologic agent of whooping cough is

Bortadella pertussis

Which of the following best characterizes Penicillium mernefei, a relatively rare etiologic agent of opportunistic disease in the U.S. with the exception of imported cases mostly in HIV-positive patients?

Branching, septate hyphae with brush-like reproductive structures

Rhinocerebral zygomycosis is the most common disease caused by members of the taxonomic class zygomycete, order Mucorales. The organisms in this taxon are notable for

Broad, hyaline, sparsely septate hyphae, larger than most other molds

Which of the following zoonotic illnesses does not have an anthropoid vector

Brucellosis

Choose the workers and the best is the clinical and diagnostic criteria described below. Clinical findings: A five year old boy with diabetic ketoacidosis has ? of his right eye, perorbital swelling and a necrotic skin lesion under his eye. Laboratory findings: biopsy of the skin lesion shows broad (10um and greater) nonseptate hyphae with right-angle branching and ribbon-like folding.

Mucor or Rhizopus species

What is the target receptor cell for Epstein barr virus

C3d complement receptor on b lymphocytes

Macrophage tropic variants of HIV-1 bind to susceptible human cells that expresses the chemokine receptor

CCR5

Systemic fungal infection that is usually endogenous in origin

Candidiasis

AIDS is caused by human retrovirus that primarily infects and kills

CD4 Positive T lymphocytes

A neonate exhibits hepatosplenomegaly rash and intracerebral calcifications have been noted from radiography. The mother had symptoms similar to mononucleosis during the third trimester of her pregnancy what is the most likely cause of this disease

CMV

Regarding CMV which one of the following is the most accurate

CMV infection of a fetus during the 1st trimester results in more congenital abnormalities than infection in 3rd trimester

An outbreak of diarrhea with fever and abdominal cramps follows a community picnic. Curved gram negative bacilli are isolated from most cases. The organisms do not grow on MacConkey agar but do not grow on selective media at 42 degrees Celsius. The most likely cause of the outbreak is

Campylobacter jejuni

A 24-year-old man with AIDS Develops a painful, thick, white exudate on the surface of his tongue and posterior pharynx. Gram stain reveals a positive organism 2 to 3 times as large as Staphylococcus aureus bacterial cells. Which organism is most likely responsible for this men's infection?

Candida albicans

Your patient is an intravenous drug user with previous history of hepatitis and wound botulism. He currently presents with symptoms consistent with endocarditis. Blood cultures taken at several times grow creamy white colonies of yeast cells. The most likely etiological agent is

Candida parapsilosis

Strep pneumonia can escape phagocytic clearance by which mechanism

Capsule mediated inhibition of phagocytosis

Staphylococcus can be distinguished from streptococcus by performing a

Catalase test

Calcofluor white attached to which component of the fungal cell?

Chitin

Which of the following bacteria causes atypical pneumonia in immunocompetent adults?

Chlamydia pneumoniae

Which of the following organisms is the etiologic agent lymphogranuloma venereum a STD rarely seen in the US other than in imported cases but endemic to parts of Africa, Asia, and South America

Chlamydia trachomatis

Which of the following statements is the most accurate in regards to hepatitis C virus

Chronic infection with HCV predisposes to hepatocellular carcinoma

Your patient is a 33 yr old man who developed peritonitis as a result of a ruptured appendix. He responded well to a ceftazidime and climdamiocyn therapy. But one week later developed fever abdominal cramps and watery diarrhea which progressed to bloody diarrhea endoscopy confirms your suspicion of pseudomembranous colitis caused by

Clostridium deficile

Choose a description of the skin vesicles of HSV from the choices below

Clear vesicle on an erythematous base

Which of the following genera includes a pathogen most often associated with bacterial myonecrosis

Clostridium

Four members of a family consumed home made canned beans and became extrememly sick and experienced a slight paralysis. The toxin is produced under aerobic conditions by this organism. The clinical vignette is most commonly associated with which of the following bacteria

Clostridium botulinum

A camper in a remote region accidentally shot himself in the leg. He dressed his wound and attempted a 5 day hike for assistance. The wound became inflamed and developed a foul odor and discoloration. Later physicians detected a gram positive rod shaped bacteria in culture from the wound. This clinical vignette is most commonly associated with which bacteria

Clostridium perfiringens

A 36 year old patient presented with dyspnea, hemoptysis and fever. The patient provided a history of extensive travel throughout the united states as well as of having experienced a "flu-like" illness accompanied by a macular rhythematous rash several months previously. Several cavitary lesion are noted in the right lung on x-ray. A Gomori methenamine silver stain of a section of biopsy collected from the periphery of a 3 cm cavity shows rudimentary hyphae and a few non - budding , round thick walled structure 20 - 30 um in diameter. The MOST probable cause of the patients illness is:

Coccidiodes immitis

Choose the organism that best fits the clinical and diagnostic criteria described below. Clinical findings: 26-year-old man with A neck mass and a right axillary mass. Patient has arrived to the United States for Vietnam's seven years ago, lives in Boston for one year it has been living in Phoenix for the past six years. Laboratory findings: Neck mass was drained and submitted for bacterial, mycobacteria and fungal culture. After two days, and white mold was growing on the blood agar plate in the routine bacterial culture. The hyphae did Not have any identifying characteristics upon microscopic examination. After further incubation time the culture demonstrated the presence of arthroconidia

Coccidioides immits

HSV and CMV share many features which one is not shared

Congenital abnormalities due to trans placental passage

How does the ebola virus spread

Contact with blood or bodily fluids of an infected person Exposure to contaminated needles Transmitted from wild animals to humans

Of the viruses listed below which is the most specifically associated with hand, foot, and mouth disease

Coxsackie A virus

You have made a clinical diagnosis of meningitis in a 50 yr old immunocompromised woman. A latex agglutination test on the spinal fluid for capsular polysaccharide antigen is positive. Of the following organisms which one of the following is the most likely cause of the disease

Cryptococcus neoformans

A 22-year-old man living in Costa Rica develops a hemorrhagic fever and shock. His wife recalls 7 years earlier he recovered an episode of high fever, rash, headache, and severe back and bone pain lasting approximately 1 week. Acute and convalescent sera taken from the patient were both positive for the same virus. Why is this episode of disease so much more severe than the previous one?

Current infection with a related strain enhanced immunopathogensis

What is the most common type of anthrax

Cutaneous

A 42 yr old man with a history of heroin addiction complains of jaundice, dark urine, anorexia, abdominal pain, and malaise. The disease rapidly progresses to fulminant hepatitis and cirrhosis. Which virus is responsible for these findings

Deltavirus

Person to person transmission of inhalation anthrax

Does not occur

A 3 yr old boy has a temperature of 40 degrees for 4 days. After a day without fever he develops a generalized rash. The rash lasts for 2 days at which time is the child contagious

During the fever

Hairy oral leukoplakia is an unusual manifestation of an infection by which of the following viruses

EBV

A pregnant patient complains of fever lower back pain and painful urination culture of urine indicates more that 105 bacteria that exhibit hemolysis on blood agar and pink colonies on MacConkey agar the most likely etiology of the uti is

E. coli

Which of the following organisms is the most common cause of urinary tract infections?

E. coli

Which of the following is likely to be isolated from a human bite infection?

Eikenella corrodens

By which mechanism do members of the family chlamydiacea survive and replicate in humans

Elementary body prevents phagolysosomal fusion

A 48 yr old man complains of severe pain caused by a belt of vesicular lesions across the right side of his abdomen what is the source of his infection

Endogenous reactivation of an earlier infection

The pathology of toxic shock syndrome associated with the production of toxic shock syndrome toxin -1 is most likely related to which activity of the toxin

Endotoxin Superantigen

What pseudomonas aeruginosa virulence factor is identical in its mode of action to diphtheria toxin

Endotoxin A

Which component is present in fungi?

Ergosterol

The parvovirus b19 viral attachment protein binds to what cellular molecule to establish infection

Erythrocyte blood group p antigen

The herpes viruses are able to evade the hosts immune response by which mechanism

Establish latent infection

Which of he following outcomes is most common following primary herpes simplex virus infection

Establishment of latent infection

Pneumocystis jiroveci often colonizes human skin.

False

Small changes in the surface glycoprotein antigen of the influenza virus is called

Genetic drift

Are special structures produced by Candidia Albicans when isolates are cultured at 37 degrees in human serum, such growth is diagnostic under

Germ tubes

A woman was hiking in an isolated area, when a skunk appeared and bit her on the leg. She now presents to your emergency room about an hour after the invite. Which one of the following is the most appropriate thing to do?

Give the rabies vaccine and hyperimmune globulin immediately

The HIV-1 viral attachment protein is

Gp120

What is the expected morphology to be seen on the gram stain for Neisseria meningitides

Gram negative diplococci

Leptospira interrogans is best described as

Gram negative spirochete

What is the expected morphology to be seen on a gram stain for Corynebacterium diphtheria?

Gram positive club shaped rods

What is the expected morphology to be seen on the gram stain for strep pyogenes?

Gram positive cocci in chains

What is the expected morphology to be seen on the gram stain for strep pneumoniae?

Gram positive lancet shaped cocci

What is the expected morphology to be seen on the gram stain for erysipelothrix rhusiopathiae

Gram positive rods

Which of the following analyses will allow clinical microbiology lab to differentiate between Neisseria gonorrhea and N. meningitides?

Growth in media containing maltose as a sole carbohydrate source

Your patient is a 27 yr old man with complaints of fever, chills myalgia resembling influenza or infectious mononucleosis that has been persistent for two weeks tests for influenza antigen and heterophile antigen are both negative. He has not had any known contact with any sick patients but did have unprotected sex about 4 weeks ago with a new partner. Based on the history you recommend the patient should be tested for HIV of the tests available which test should be used to detect infection in this patient

HIV antibody and p24 antigen test (4th generation)

A 10 yr old boy was diagnosed with meningitis a sample of his csf was cultured and showed no growth on blood agar. White colonies grow on chocolate agar. The gram stain showed plenty rod shaped organisms. This clinical vignette is most commonly associated with what organisms

Haemophilus influenza

Several pathogens are transmitted either during gestation or at birth from mother to fetus which of the following is least likely to be transmitted at those times

Haemophilus influenza

Which coccobacilliary gram negative rod causes meningitis in young children

Haemophilus influenza

X factor (hemin) and v factor (nicotinamide adenine dinucleotide) are needed for the growth of

Haemophilus influenza

A previously healthy 52 yr old female suddenly develops acute respiratory distress and severe hypotension. She dies in the intensive care unit of her local hospital two days later. During the previous week she and her husband had spent three days cleaning and repairing an old abandoned cabin they had recently purchased in northern Minnesota, no history or evidence of insect bites was reported. what was the most likely cause of her illness

Hanta virus

Which of he following viral diseases has the longest incubation period

Hepatitis B

Choose the organism that best fits the clinical and diagnostic criteria described below. Clinical findings: Fever, myalgia, and shortness of breath on exertion in a 34-year old male farmhand here recently cleaned in Missouri barn that had a large starling population; focal pulmonary infiltrates found by radiography. Laboratory findings: at 25 degrees, septate hyphae with large (8 to 15um) tuberculate macroconidia; at 37 degrees, small (2-4 um), round to oval, budding yeast cells.

Histoplasma capsulatum

Which of the following is a dimorphic organism that typically is acquired by inhalation of spores during excavation of soil during construction or exploration of bat infected caves in areas of endemicity

Histoplasma capsulatum

Unlike adult food borne botulism infant botulism is most often associated with ingestion of

Honey

A 2 yr old boy has a sudden onset of fever of 104 degrees that lasts for 4 days and then develops a faint macular rash that covers his body and lasts only 48 hrs the agent causing the disease is sensitive to detergent inactivation which agent is the most likely cause of his symptoms

Human herpes virus 6

Of the viruses listed below which one is most specifically associated with exanthem subitum

Human herpes virus 6

Which one of the following is a virulence factor for Neisseria gonorrhea?

IGA protease

A pap stained cervical smear from a sexually active 36 yr old woman with cervical dysplasia shows cells with enlarged nuclei and cytoplasmic vacuoles koiliocytic cells. Indicating a viral infection which technique would be useful to confirm the diagnoses of the agent most likely to be present in these cells

In situ DNA hybridization analysis of cells from the cervical smear

Which one of the following statements concerning infectious mononucleosis is the most accurate?

Infectious mononucleosis is transmitted by virus in saliva

Which of the following viral diseases has the shortest incubation period?

Influenza

A 4 yr old African American male developed a fever sore throat and irritability. Her has about 20 small macular lesions in his mouth that have white enters that appear like grains of salt with a red halo. The pharyngeal walls are extremely red. The child has no obvious rash. Transmission of the disease occurs most often though

Inhalation of aerosol droplets

The most common mechanism of antibiotics is

Inhibition of cell wall synthesis

Staph aureus can escape phagocytic clearance by which mechanism

Inhibition of opsonisation mediated protein A Capsule mediated inhibition by of phagocytosis

Fransciella tulaferanis can escape phagocytic clearance by which mechanism

Inhibition of phagosome/ lysosome fusion

Characteristics of a bacterial capsule include

It is an important mechanism for protecting bacteria against ingestion by polymorphonuclear cells

A 35 yr old man who is HIV positive has a low CD4 count of 30 says I can't remember the simplest things. An MRI indicates several widely scattered lesions in the brain. Over the next 4 months he develops visual defects. Becomes paralyzed and dies. Autopsy reveals pathology of foci of demyelination with oligodendrocytes containing inclusion bodies only in the white matter. Presence of PCR amplified viral DNA confirms the diagnosis of a nonenveloped virus. Which one of the following viruses is the most likely cause

Jc virus

Which of the following organisms is frequently implicated in nosocomial infections is an important cause of community acquired pneumonia in adults and has a thick mucoid capsule

Klebsiella pneumonia

The enterobacteriacea produce a variety of virulence factors with different modes of action. Which of the following is a potent endotoxin component found in the cell wall of an enterobacteriace?

LPS endotoxin

The morphology of streptococcus pneumoniae is most frequently described as

Lancet shaped

Three patient present to an inner city hospital with infections subsequently demonstrated to be caused by the same organism the first patient a 23 yr old prostitute presents with a temperature of 38.5 degrees' hypotension, icterus pulmonary rales and muscle tenderness the second patient a 38 yr old male has the same temperature icterus mild upper quadrant tenderness and muscle tenderness. The third patient an 8 yr old male has flu like symptoms a low grade fever and muscle tenderness. The first and third patient cut their feet on glass in a city alley. The patients had not been in contact with each other and none had significant travel history. Two patients developed meningitis a fourth patient is subsequently reported to public department with the same illness. This patient's illness develops after swimming in a city reservoir. Which organisms is responsible

Lepospira interrogans

Infection with Neisseria gonorrhea is characterized by intracellular growth of the bacteria and stimulation of a vigorous inflammatory response. Which virulence factor is responsible for the inflammatory response

Lipooligosaacharide (LOS)

A 2 year old girl was diagnosed with meningitis. A sample of her CSF was cultured on blood agar and grew tiny catalase positive beta hemolytic clear colonies further testing shoes motile rod shaped organisms

Listeria monocytogenes

Granulomatosis infantiseptica is caused by

Listeria monocytogenes

Which is the following is not a symptom of Ebola virus disease?

Loss of sight

A 58 year old woman complained of flu-like symptoms, severe headache, stiff neck, and photophobia. She was lethargic and had a mild fever. The CSF contained 900 WBC/ml mostly lymphocytes. She and her husband had been cleaning their summer home in mountains which was infested with mice. She recovered after a week. Based on her history and symptoms, what is the likely cause of her symptoms?

Lymphocytic choriomeningitis virus

Which of the following viral pathogens is transmitted by rodent rather than arthropods

Lymphocytic choriomeningitis virus

Which fungus skin infection would best be described as hyperpigmented, non-pruritic macular lesion on skin of back caused by a lipophilic yeast?

Malssezia furfur

A 4 yr old African American male developed a fever, sore throat, and irritability. He has about 20 small macular lesions in his mouth that have white enters that appear like grains of salt with a red halo. The pharyngeal walls are extremely red. The child has no obvious rash. The most likely diagnosis in this case is

Measles

Which fungus would best be described as a zoophilic dermatophyte with separate hyphae and Large, thick, rough-walled macroconidia?

Microsporum canis

Which fungus would best be described as the agent causing tinea capitus with classic ringworm pattern of dermatophytosis

Microsporum canis

The usual site of reactivated herpes simplex type 1 virus is the

Musculocutaneous junctions

A 30 yr old patient with advanced HIV (AIDS) is admitted to the hospital with a high fever. Blood cultures are performed and you receive a report from the laboratory that they are growing a mycobacterium. The one that is most likely is:

Mycobacterium avian intracellular complex

Which non-pathogenic slow growing mycobacterium species is isolated often from clinical specimens as a contaminant due to presence in water and discrimination from pathogens is a relevant diagnostic issue?

Mycobacterium gordonae

Which mycobacteria is photochromogenic

Mycobacterium kansasii

Which term is the clinical disease description for a disease caused by streptococcus pyogenes that is characterized by substantial damage to muscle and fatty tissues

Necrotizing fasciitis

The lab informs you that a gram positive branching filamentous organism recovered from sputum specimen was found to be positive with a modified acid fast stain method. What is the most likely presumptive ID

Nocardia

Which of the following organisms is most likely to be observed in aerobic culture to have grown above the agar surface resembling the aerial hyphae of molds and stains weakly acid fast

Nocardia brasilliensis

Your patient is a 47 yr old migrant worker who presents with a grossly swollen foot with multiple draining sinus tracts. Hs gait is impaired even though he claims no foot pains. A swab pressed deep into one of the sinus tract yields filamentous branching gram positive rods under aerobic culture conditions the most likely etiologic agent of infection is

Nocardia brasilliensis

The most sensitive diagnostic test for Bordetella pertussis would be

Nucleic acid based amplification assay

To make a diagnosis of HSV encephalitis the most sensitive assay from the list would be

PCR for HSV viral sequences in CSF

Which test can be used to confirm the identity of strep pneumonia growing from a culture

Optochin susceptibility

The preliminary ID of a pathogenic Neisseria species can be made by isolation of

Oxidase positive gram negative diplococci growing on a chocolate agar or on a media that are selective for pathogenic Neisseria species

Which of the following food is most often associated with septicemia caused by vibrio vulnificus?

Oysters

Of the viruses listed below which is the most specifically associated with condylomata accuminatum

Papillomavirus

Choose the organism that best fits the clinical and diagnostic criteria described below. Clinical findings: oral and nasal ulcerative lesions in a 45-year old farmer who had recently emigrated from his native Venezuela. Laboratory findings: at 25 degrees, septate hyphae with intercalated chlamydoconidia; at 37 degrees, thick walled yeast cells with multiple, narrow-based buds around their circumference; the same yeast morphology was observed in biopsies of the ulcers and in KOH preparations of skin scrapings ?? periphery of the lesions.

Paraccidioids brasiliens

Lower respiratory tract viral infections can also result in more serious disease such as bronchiolitis pneumonia and related diseases which pair of viruses listed below is known to cause major respiratory problems for infants and children

Parainfluenza and respiratory syncytial virus

A 4 yr old child is brought to the emergency department because of continuous loud barking cough and difficulty catching her breath improves in the presence of purified air. A virus is identified from the nasal wash specimen by dfa if the virus was grown in culture it would promote syncytia formation in cultured cells. Which virus is more likely the cause of the patient's condition

Parainfluenza virus

Which property is responsible for the survival and replication of mycobacterium tuberculosis in an infected patient

Phagocytized bacteria inhibit phagosome lysosome fusion

Histologic sections of a lesion from a patient with chromoblastomycosis characteristically show:

Pigmented sclerotic bodies

In tissue sections, Sporothrix schenckii is characterized by:

Pleomorphic yeast cells, spherical and/or cigar shaped, 2- 10 microns in diameter

A multi drug resistant gram negative rod is isolated from a gravelly ill elder man who is hospitalized from treatment for obstructive pulmonary disease. The organism is oxidase positive non fermenting and incapable of anaerobic growth which leads you to hypothesize that is

Pseudomonas aeruginosa

Which of the following bacteria is an oxidase positive gram negative rod and an important cause of wound and burn infections

Pseudomonas aeruginosa

Which one of the following is a virulence factor for staph aureus

Protein a that binds to the Fc portion of IgG

Which of the following organisms is endogenous flora associated with urinary tract infections and has characteristic swarming motility on culture agar

Proteus mirabilis

A 60-year-old patient in the burn unit of a hospital develops an infection in the burned tissue. Cultures of material from the infected site revealed gram negative bacilli that grew on blood agar chocolate and MacConkey agar. The colonies were large dry spread colonies with a grape like odor. The organism is most likely what

Pseudomonas aeruginosa

Which of the following organisms is associated with skin and soft tissue infections as this organism can colonize water and form biofilms

Pseudomonas aeruginosa

Five members of a family aged 17-55 had onset fever three had anorexia, three had cough, three had headaches, two were vomiting and all had myalgia. Evaluation of three of the patients included chest x ray showing diffuse interstitial pulmonary infiltrates. Nasal aspirates revealed no unusual findings for cultivable bacteria or viruses. Family pets include a small terrier dog four yrs in the household and a cockatiel bird purchased a month prior to the onset of symptoms. The pneumonia experienced supports a presumptive diagnosis of

Psittacosis

In the 2009- 2010 dengue virus outbreak in florida what factors contributed the most in prevention of an epidemic or dengue fever in Florida

Public education about dengue virus and successful vector control efforts

Regarding respiratory syncytial virus which one of the following statements is most accurate

RSV is an important cause of bronchiolitis in infants

A 20 yr old woman who works in a pediatric unit begins to suffer from fatigue sneezing and a runny nose she has no fever but she soon develops a mild sore throat a headache and a stuffy nose. Her symptoms subside within 3-4 days which virus is the most likely cause of these symptoms

Rhinovirus

Which of the following foods is most often associated with food poisoning cased by b. cereus

Rice

A male hunter noticed a rash on his legs that spread to his hands, the first rash appeared where he has removed ticks after an outing in the woods. He was also febrile and developed a non productive cough. Blood cultures were negative and his diagnosis was confirmed by serology testing. What is the most likely pathogen responsible for his illness

Rickettsia rickettsi

A 6-month old boy was seen in the ER in Jan after 2 days of persistent watery diarrhea and vomiting accompanies by a low-grade fever and mild cough. The infant appeared dehydrated and required hospitalization. The patient attended a day car center. His diagnosis was made by EIA assay of the stool specimen. What is like cause of this disease?

Rotavirus

A knee wound on a 45 year old woman became infected. A culture of the pus revealed clustered cocci which produce complete hemolysis of blood agar plates. A coagulase test was positive

Staph aureus

Of the following gents which is the most common cause of uti in sexually active young woman

Staph saprophyticus

Which of the following organisms is a major etiological agent of food poisoning in humans

Staph. Aureus

A major concern regarding the pathogenesis of influenza infections in the elderly is

Secondary bacterial infection

A 37 yr old man experiences a sudden onset of sneezing runny nose mild headache cough and fatigue but not fever. The symptoms last for approximately 1 week and then the man feels fine. What characteristic of the viral agent distinguishes it from other members of the family

Sensitive to acid pH

The binding site of the beta lactam antibiotics is bacterial

Serine proteases

You suspect your patient has infectious mononucleosis but the heterophile antibody test is negative. What testing would you do next to confirm your diagnosis

Serologic testing for specific antibody to EBV viral antigens

Bordetella pertussis clinical disease occurs in multiple stages which statement below most accurately describes the first stage of infection

Serous rhinorrhea, sneezing, malaise, anorexia, and low grade fever

Treponema pallidum infections are most commonly transmitted by

Sexual intercourse

A cautious 33 yr old office worker decided to get vaccinated before the pending flu season. Her physician vaccinated her with an intramuscular dose containing the following virus strains a/California/7/2009 h1n1, a/perth/16/2009 h3n2, b/Brisbane/60/2008. Four weeks after receiving the vaccine the woman developed an abrupt high fever myalgia headaches, chills and a dry unproductive cough. The cough became progressive with the general symptoms lasting three weeks. Her doctor told her that she had the flu even though she had received the vaccine and serology testing demonstrated that she had received the vaccine and serology testing demonstrated that she had an immune response to influenza a and b viruses why is this possible. Chose the most likely explanation

She was infected by a novel strain of influenza not part of the trivalent vaccine

Hemolytic uremic syndrome is associated with the toxic activity of

Shiga toxin

The enterobacteriacea produce a variety of toxins and virulence factors with different modes of action. Which of the following is a potent exotoxin which induces eukaryotic cell death by blocking protein synthesis?

Shiga toxin

Which of the following bacteria has the lowest infectious dose

Shigella

A 32 yr old man experienced diarrhea cramps and bloody stools following a business encounter group session in a campsite area. Stool specimens plated on MacConkey agar produced clear colonies of gram negative rods what is the most likely pathogen responsible for his illness

Shigella sonnmei

A sexually active 22 yr old female college student develops fever painful urination and flank pain. Her urine is remarkable for rbc, wbc, and gram positive cocci. The most common cause of this uti is

Staph. Saprophyticus

While completing your family medicine rotation in a community clinic you encounter a patient with bollus impetigo. The most likely cause of this of this illness is

Staph. aureus

A second year medical student from the university of Florida medical school choses to spend the summer working in a relief organization. She was sent to a native American reservation in the western badlands. Most of the patients coming to the small clinic had not received periodical medical exams. One child entered with tonsillitis, malaise sore throat and fever. A gray white thick membrane covered the tonsils and the soft plate. A gram stain of throat smears would most likely show

Small club shaped gram positive bacilli

Blastomyces dermatitidis growing at 25 degrees on standard mycologic medium?

Spherical to oval or pear-shaped conidia on variable length hyphal branches

Which feature is unique to gram positive bacteria

Spore formation

Which fungus would best be described as the agent causing lymphadenopathy of hand about several weeks after patient observed small papule forming at the site of a splinter wound (incurred while playing with mulch in garden with bare hands)? The papule ulcerated about two weeks after it appeared.

Sporothrix schenckii

Choose the organism that best fits the clinical and diagnostic criteria described below. Clinical findings: 65-year-old woman with A 2 cm ulcerated lesion on the palm of her hand. They have been getting bigger and the last two weeks. She has been making holly wreaths for use at Christmas. Laboratory findings: an aspirate of the lesion show 2-10um pleomorphic yeasts. The cultured isolate at 25 degrees had delicate thin hyphae, septate, with branching clusters of pear shaped or almost round conidia.

Sporothrix schenkii

The mode of action of botulinum toxin is

Stimulates host cell adenylate cyclase

A culture of skin leisons from a patient with pyoderma (impetigo) shows numerous colonies surrounded by a zone of beta hemolysis on a blood agar plate. A gram stained smear shows gram positive cocci. If you found the catalase tests to be negative which of the following organisms would you most probably have isolated

Strep pyogenes

Acute glomerulonephritis is a nonsuppurative complication that follows infection by which one of the following organisms?

Strep pyogenes

Approximately 2 weeks after orthopedic surgery for repair and an ankle fracture. A 27 yr old man develops purulent redness and discharge at the surgical site. When this patient sees his physician the site is tender and warm and the patient has a fever. Cultures are taken and submitted to the lab. The lab calls the physician 24 hrs later and reports the growth of gram positive cocci in chains and the catalase test is negative which organism is the most likely cause of the mans condition

Strep pyogenes

A group of preschoolers attending a daycare facility all developed fevers and severe sore throats. Cultures of the throat swabs grew beta hemolytic colonies

Strep pyogenes group A

The 35 yr old father of a 3 yr old experiences the sudden onset of fever fatigue nausea stomach pain and loss appetite. Jaundice is observed 5 days later. Which piece of information from the patients history is the key to differentiating which hepatitis infection is occurring

Sudden onset of symptoms

Each of he following statements concerning viruses is correct except

Viruses replicated by binary fission

Which type of immune deficiency allows patients to be particularly susceptible to severe infection by listeria monocytogenes

T cell mediated immunity

A 25 yr old man with facial pain visited the emergency room. He was unable to open his mouth because of the spasms in the facial muscles and has been unable to eat for 3 days because of the pain and stiffness a clinical history revealed that the young man has been searching for scrap metal in a junkyard and accidentally stepped on a jagged piece of metal projecting from the soil. He self treated the wound and ignored it until he started to experience the facial tightness and pain. The symptoms described are most consistent with which presumptive diagnosis

Tetanus

Regarding norovirus which one of the following is the most accurate

The diarrhea caused by norovirus contains no neutrophils or red cells in the stool

You suspect that your patients disease may be caused by Cryptococcus neoformans. Which one of the following findings would be most useful in establishing the diagnosis?

The finding of encapsulated budding cells in spinal fluid

You have isolated a virus from the stool of a patient with a known characteristic that its genome is composed of multiple pieces of RNA. Which of the following is least likely to be true

The genome integrates into the host chromosomes

Viruses enter cells by absorbing to specific sites on the outer membrane of cells. Each of the following statements regarding this event in the virus cycle is correct except

The interaction determines whether the genome of the virus is infectious

A 36 year old woman with elevated AST and ALT levels has serum collected for viral serologic studies. The results are listed below: Hep B surface antigen: positive; Hep B surface antibody: negative; IgM antibody to Hep B core antigen: negative; total antibody to Hep B core antigen: positive; Hep C antibody: negative; IgM antibody to Hep A: negative; total antibody to Hep A: positive. Which of the following conclusion can you draw from these results?

The patient has chronic Hep B

A medical student who suffers from common cold symptoms including a runny nose sore throat sneezing and a headache asks her professor to explain why a vaccine has not been developed to prevent this disease which explanation is the best one

There are too many agents that cause this disease

You are director of infection control in a community hospital. A group of nurses has asked yo speak to you about a patient who is coughing excessively due to pulmonary histoplasmosis and is wandering freely throughout the hospital. You tell them that

There is no person-person transmission of this illness

A young woman in southern Florida desire in a fashionable suntan. The results were not what she had anticipated. Her tan appeared uneven with well outlined, hypopigmented lesion on her upper torso. Her dermatologist performed a microscopic examination of cutaneous scales of skin using KOH and observed yeast cells and hyphae. The history and examination are MOST Consistent with a preliminary diagnosis of:

Tinea versicolor

The plasma from a travelling salesmen was positive in the RPR test which organism is responsible for this test result

Treponema pallidum

Direct exam of clinical specimens most rapid and cost effective means of diagnosing fungal infections.

True

The most useful microscopic morphological feature of the mycellial phase of Histoplasma capsulaum that can be used for presumptive identification is:

Tuberculate macroconidia, 8 to 15 microns in diameter

For which of the following enteric illnesses is a chronic carrier state most likely to develop

Typhoid fever

VCZ virus and HSV share many characteristics which one is not shared

Unapparent disease manifested only by virus shedding is common

The capsules of slime layers of most bacteria are

Unnecessary for growth but improve survival in host

Global eradication of smallpox was achieved by vaccination with this virus

Vaccinia

Of the virus listed below which is most specifically associated with smallpox

Variola virus

Which of the following is the most reasonable explanation for the ability Hep B virus to cause chronic infection

Viral DNA can persist within the host cell

A horse trainer keeps his horses in facilities that are clean but located near a marsh. A newly purchased towards becomes infected with the Western equine encephalitis (WEE) virus. The veterinarian assures the trainer that he and his other courses are not at risk of acquiring WEE Infection from the sick horse. Which explanation best describes this insurance?

Viremia in a horse is not sufficient to promote transmission

Most cases of leigonellosis are associated with contact with contaminated

Water