Medical microbio final multiple choice questions

Which of the following individuals should routinely receive vaccination with the conjugate meningococcal vaccine? a. A healthy young adolescent entering high school b. A healthy child entering kindergarten c. A 60-year-old man with insulin-dependent diabetes d. A healthy 40-year-old technician who works in a cancer research laboratory e. A 65 year old woman with coronary artery disease

a. A healthy young adolescent entering high school

Optimum recovery of Yersinia enterocolitica from the stools of patients with gastroenteritis requires which of the following specialized media? a. Cefsulodin-Irgasan-novobiocin (CIN) agar b. Xylose-lysine decarboxylase agar c. Hektoen-enteric agar d. Regan-Lowe medium e. MacConkey agar

a. Cefsulodin-Irgasan-novobiocin (CIN) agar

A 42 year old woman went camping in the Sierra Nevada Mountains, where she slept for 2 nights in an abandoned log cabin. After the second night, a tick was found on her shoulder. 6 days later, she developed a fever of 38*C, which lasted for 4 days. 10 days later, she had another similar episode of fever. Examination of a blood smear stained with Wright stain showed spirochetes suggestive of Borrelia species. Which of the following statements about relapsing fever and Borrelia hermsii is correct? a. Each relapse is associated with an antigenically distinct variant b. Blood smears should be made when the patient is afebrile c. Borreliae do not pass transovarially from one generation to the next in ticks d. The main reservoir for the Borrelia is deer e. Borrelia hermsii is resistant to penicillin and tetracycline

a. Each relapse is associated with an antigenically distinct variant

. A food commonly associated with Bacillus cereus food poisoning is a. Fried rice b. Baked potato c. Hot freshly steamed rice d. Green beans e. Honey

a. Fried rice

A 10 year old child has a primary pulmonary Mycobacterium tuberculosis infection. Which of the following features of tuberculosis is most correct? a. In primary tuberculosis, an active exudative lesion develops and rapidly spreads to the lymphatics and regional lymph nodes. b. The exudative lesion of primary tuberculosis often heals slowly c. If tuberculosis develops years later, it is the result of another exposure to M. tuberculosis d. In primary tuberculosis all of the infecting M. tuberculosis organisms are killed by the patient's immune response. e. In primary tuberculosis, the immune system is primed, but the PPD skin test results remain negative until there is a second exposure to tuberculosis

a. In primary tuberculosis, an active exudative lesion develops and rapidly spreads to the lymphatics and regional lymph nodes.

Movement of Listeria monocytogenes inside of host cells is caused by a. Inducing host cell actin polymerization b. The formation of pili (fimbriae) on the listeria surface c. Pseudopod formation d. The motion of listeria flagella e. Tumbling motility

a. Inducing host cell actin polymerization

. All of the following statements regarding the epidemiology of infections caused by Yersinia enterocolitica are correct except a. Most human infections are caused by serotype 0:1 b. Humans acquire the infection from ingestion of food or drinks contaminated by animals or animal products c. Person to person spread is quite common d. A large inoculum is required to cause infection e. Infection is more prevalent in persons with histocompatibility antigen HLA-B27

a. Most human infections are caused by serotype 0:1

All of the following are properties characteristics of Bacillus anthracis EXCEPT a. Motility on wet mount examination b. Medusa head colonies c. Poly-d-glutamic acid capsule d. In vitro susceptibility to penicillin e. Absence of hemolysis on 5% sheep blood agar

a. Motility on wet mount examination

Which is an important virulence factor of Bacillus anthracis? a. Protective antigen b. Lipopolysaccharide c. Pili d. A toxin that inhibits peptide chain elongation factor EF-2 e. Lecithinase

a. Protective antigen

A patient presents to the emergency department with nonbloody diarrhea for 12 hours. The patient lives in Washington DC and has not recently traveled out of the area. Which one of the following is unlikely to be the cause of your patient's diarrhea? a. Salmonella typhi b. Campylobacter jejuni c. Shigella sonnei d. Vibrio cholerae

a. Salmonella typhi

Bacteremia associated with a gastrointestinal infection is most likely to occur with which of the following? a. Salmonella typhi b. Vibrio cholerae c. Shigella boydii d. Vibrio parahaemolyticus e. Campylobacter jejuni

a. Salmonella typhi

Which one of the following statements about Chlamydophila pneumoniae is most correct? a. Transmission from person to person is by the airborne route b. It makes glycogen-rich inclusions that stain with iodine c. There are multiple serovars, including 3 that cause a systemic illness d. They are resistant to macrolides e. The reservoir is house cats

a. Transmission from person to person is by the airborne route

Which of the following spirochetes are transmitted primarily by sexual contact? a. Treponema pallidum subspecies pallidum b. Borrelia recurrentis c. Borrelia burgdoferi d. all of the above

a. Treponema pallidum subspecies pallidum

An older gentleman visited his favorite oyster restaurant in a small town on the eastern shore of the Gulf Coast of Texas. He ate 2 dozen oysters. 2 days later, he was admitted to the hospital because of an abrupt onset of chills, fever and light-headedness when he stood up (in the emergency department). His blood pressure was 60/40 mmHg. While in the ED, he developed erythematous skin lesions. These rapidly evolved into hemorrhagic bullae which then formed ulcers. The man drinks a 6 pack of beer and .5 bottle of whisky each day. A microoganism of major concern for the patient is a. Vibrio vulnificus b. E. coli c. Salmonella typhi d. Colstridium perfringens e. Streptococcus pyogenes (group A streptococci)

a. Vibrio vulnificus

Inclusion conjunctivitis of the newborn a. is a mucopurulent conjunctivitis that occurs 7 - 12 days after delivery b. is caused by C psittaci c. Is a result of exposure to pet birds in the home d. Is treated with systemic penicillin because it may progress to pneumonia e. None of the above

a. is a mucopurulent conjunctivitis that occurs 7 - 12 days after delivery

An important factor in the pathogenesis of Legionnaires' disease is that a. Legionella pneumophila kills polymorphonuclear cells b. Alveolar macrophages phagocytose Legionella pheumophilia c. Legionella pneumophila induces alveolar macrophage phagosomes to fuse with lysosomes e. Legionella pneumophila outer surface protein A (OspA) is important for invasion of alveolar macrophages

b. Alveolar macrophages phagocytose Legionella pheumophilia

An infant is brought to the pediatric emergency department in severe respiratory distress. The child appears dehydrated and there is a prominent peripheral lymphocytosis. The chest radiograph reveals perihilar ( 🐷situated around a hilus, hila - lung root including bronchi and pulmonary arteries and veins) infiltrates. The child's grandmother who watches the infant now that the mother has returned to work has a dry hacking cough for 2 weeks. The most likely causative agent is a. Haemophilus influenzae type b b. Bordetella pertussis c. Streptococcus agalactiae d. Chlamydia pneumoniae e. Bordatella bronchiseptica

b. Bordetella pertussis

All of the following statements regarding relapsing fever are correct except a. Epidemic disease carries a higher mortality rate than endemic disease b. Endemic disease in North America is caused by B. recurrentis c. The recurrent febrile episodes are caused by antigenic variation among the spirochetes d. Penicillin is the drug of choice e. Crushing a tick could transmit the spirochetes

b. Endemic disease in North America is caused by B. recurrentis

A fisherman imbedded a fishhook into his finger. He removed it and did not seek immediate medical attention. Five days later, he noted fever, severe pain and nodular-type swelling of the finger. He then sought medical attention. The nodule was aspirated and after 48 hours of incubation, colonies of a gram-positive bacillus that caused a greenish discoloration of the agar and formed long filaments in the broth culture were noted. The most likely cause of infection is a. Lactobacillus acidophilus b. Erysipelothrix rusiopathiae c. Listeria monocytogenes d. Rhodococcus equi e. Nocardia brasiliensis

b. Erysipelothrix rusiopathiae

All of the statements below regarding infections with Legionella are correct except a. Hospitals that care for patients at risk for legionella infections should know if their potable water systems contain legionella b. Human-to-human transmission is the major mechanism of transmission of Legionella infection c. Legionella species can be visualized with Gram stain if carbol fuchsin is used for the counterstain d. The chest radiograph of a patient who has Legionella pneumonia is indistinguishable from that of patients with pneumonia caused by other pathogens. e. A macrolide of quinolone are the drugs of first choice for treatment of Legionella infections.

b. Human-to-human transmission is the major mechanism of transmission of Legionella infection

Which of the following organisms principally infects the liver and kidneys? a. Streptobacillus moniliformis b. Leptospira interrogans c. Staphylococcus aureus d. E. coli e. Enterococcus faecalis f. Treponema pallidum

b. Leptospira interrogans

Chlamydia pneumoniae pneumonia most resembles infection caused by which of the following organisms? a. Streptococcus pneumoniae b. Mycoplasma pneumoniae c. Haemophilus influenzae d. Chlamydia trachomatis e. Rhinovirus

b. Mycoplasma pneumoniae

An uncommon serotype of Salmonella enterica subspecies enterica was found by laboratories in the health departments of adjacent states. The isolates were all from a small geographic area on either side of the border between the states, suggesting a common source for the isolates. (All of the isolates were from otherwise healthy young adults who smoked marijuana; the same Salmonella was isolated from a specimen of the marijuana) By what method did the laboratories determine that these isolates were the same? a. Capsular (K antigen) typing b. O antigen and H antigen typing c. DNA sequencing d. Sugar fermentation pattern determination e. Decarboxylase reaction pattern determination

b. O antigen and H antigen typing

Which of the following cell components produced by Neisseria gonorrhoeae is responsible for attachment to host cells? a. Lipooligosaccharide b. Pili (fimbriae) c. Moraxella catarrhalis d. Neisseria gonorrhoeae e. None of the above

b. Pili (fimbriae)

A woman with a history of UTI's comes to the ER with burning on urination along with frequency and urgency. She says her urine smells like ammonia. The cause of her UTI is likely to be a. Enterobacter aerogenes b. Proteus mirabilis c. Citrobacter freundii d. Escheria coli e. Serratia marcescens

b. Proteus mirabilis

A 17-year old girl with cystic fibrosis has a slight increase in her frequent cough and production of mucoid sputum. A sputum specimen is obtained and placed on routine culture media. The predominant growths are gram-negative bacilli that form very mucoid colonies after 48 hours of incubation. These bacilli are oxidase positive, grow at 42C and have a grapelike odor. These gram-negative bacilli are which of the following? a. Klebsiella pneumoniae b. Pseudomonas aeruginosa c. Staphylococcus aureus d. Streptococcus pneumoniae

b. Pseudomonas aeruginosa

The Vibrio cholerae factor responsible for diarrhea is a toxin that a. Blocks EF2 b. Yields increased intracellular levels of cAMP c. Cleaves SNARE d. Blocks EF1 dependent binding of aminoacyl tRNA to ribosomes e. Cleaves VAMP

b. Yields increased intracellular levels of cAMP

T/F. Pontiac fever is a severe form of pneumonia caused by Legionella pneumophila a. true b. false

b. false

An elderly man had surgery for a ruptured sigmoid colon diverticulum with an abscess. The abscess was subsequently drained. He was treated with intravenous gentamicin and ampicillin. Ten days later (and 4 days after being discharged from the hospital), the patient developed malaise, fever and cramping abdominal pain. He had multiple episodes of diarrhea. His stool was positive for occult blood and the presence of polymorphonuclear cells. On sigmoidoscopy, the mucosa was erythematous and polymorphonuclear cells. The sigmoidoscopy showed the mucosa was erythematous and there appeared to be many raised white to yellowish plaques 4 - 8 mm in diameter. Which of the following is the likely the cause of the patient's problem? a. Staphylococcus aureus enterotoxin b. Bacillus cereus toxin c. Clostridium difficile toxins d. Clostridium perfringens toxin e. Enterohemorrhagic Escherichia coli

c. Clostridium difficile toxins

A 25 year old medical student has contact with a patient who has pneumonia with fever and cough. Four days later, the medical student develops fever and cough and chest radiographs show consolidation of the right lower lobe. Routine bacterial sputum culture results are negative. Pneumonia caused by Mycoplasma pneumoniae is considered. All of the following are methods to confirm the clinical suspicion except a. PCR amplification of M pneumoniae DNA in the sputum b. Culture of sputum for M pneumoniae c. Gram stain of the sputum smear d. Culture of a lung aspirate for M pneumoniae e. Enzyme immunoassay test of acute and convalescent sera

c. Gram stain of the sputum smear

Enterococci can be distinguished from nonenterococcal group D streptococci on the basis of which of the following characteristics? a. y-Hemolysis b. Esculin hydrolysis c. Growth in 6.5% NaCl d. Growth in the presence of Bile e. Gram stain morphology

c. Growth in 6.5% NaCl

An elderly man comes to the ER feeling feverish and "really tired". He has a chronic cigarette cough, but has dramatically increased in the past week and has been producing whitish sputum. The previous day he had a temperature of 38*C and watery diarrhea. Physical examination reveals inspiratory and expiratory wheezes and rales over the right lower lung field. Chest radiography shows a patchy right lower lobe infiltrate. The differential diagnosis of this patient's disease is a. Streptococcus pneumoniae pneumonia b. Legionella pneumophila pneumonia c. Haemophilus influenzae pneumonia d. Mycoplasma pneumoniae pneumonia e. All of the above

c. Haemophilus influenzae pneumonia

A plate of MacConkey agar is inoculated and grows gram negative rods. TSI agar is used to screen the isolates for salmonellae and shigellae. A result suggesting one of these 2 pathogens would be a. Production of urease b. Motility in the medium c. Inability to ferment lactose and sucrose d. Fermentation of glucose e. Production of gas in the medium

c. Inability to ferment lactose and sucrose

4. For the patient described in Question 3, which of the following is likely to be responsible for the hemolysis? a. EF b. Tetanospasmin c. Lecithinase d. Streptolysin O e. Toxin B

c. Lecithinase

Each of the following is associated with genital tract infections except a. Mycoplasma hominis b. Neisseria gonorrhoeae c. Mycoplasma pneumoniae d. Chlamydia tractomatis e. Mycoplasma genitalium

c. Mycoplasma pneumoniae

Elimination of blinding trachoma involves all of the following except a. Periodic administration of azithromycin b. Face washing and hygiene c. Periodic culture screening of conjunctiva swab specimens for Chlamydia trachomatis d. Environmental improvements to sewage systems to decrease the number of flies e. Surgery on deformed eyelids

c. Periodic culture screening of conjunctiva swab specimens for Chlamydia trachomatis

Tetanus toxin (tetanospasmin) diffuses to terminals of inhibitory cells in the spinal cord and brainstem and blocks which of the following? a. Release of acetylcholine b. Cleavage of SNARE proteins c. Release of inhibitory glycine and y-aminobutyric acid d. Release of PA e. Activation of acetylcholine esterase

c. Release of inhibitory glycine and y-aminobutyric acid

A young boy from Kansas City who recently started attending preschool and after-school daycare is brought to his pediatrician for a diarrheal illness characterized by fever (38.2C) severe lower abdominal pain, and initially watery diarrhea. His mother became concerned because the stools are now blood tinged 24 hours into the illness and the child appears quite ill. The mother reports that two other children who attend the same after-school daycare have recently had diarrheal disease, one of whom likewise has bloody stools. Which of the following is the most likely pathogen causing the disease in these children? a. An enterotoxigenic strain of E. coli b. Salmonella enterica subspecies enterica serotype (Salmonella Typhi) c. Shigella sonnei d. Edwardsiella tarda e. Klebsiella oxytoca

c. Shigella sonnei

An adolescent girl came to the clinic because of a new and unusual vaginal discharge. She had recently become sexually active and had 2 new partners during the previous month. On pelvic examination,a purulent discharge was seen at the opening of her endocervical canal. Which of the following statements about this patient is most correct? a. A serologic test for syphilis is not indicated because her symptoms are not those of syphilis b. A Gram stain of her endocervical specimen would show Chlamydia tractomatis inside polymorphonuclear cells c. The differential diagnosis includes infection with Neisseria gonorrhoeae, Chlamydia tractomatis or both d. The endocervical specimen should be analyzed for herpes simplex e. Initial treatment is with ampicillin

c. The differential diagnosis includes infection with Neisseria gonorrhoeae, Chlamydia tractomatis or both

Which of the following statements regarding O antigens is correct? a. All Enterobacteriaceae possess identical O antigen b. They are found in the polysaccharide capsulse of c. They are covalently linked to a polysaccharide core d. They do not stimulate an immune response in the h e. They are not important in the pathogenesis of infection caused by enteric bacteria

c. They are covalently linked to a polysaccharide core

The following statements about trachoma are correct except a. It follows chronic or recurrent eye infection with Chlamydia trachomatis b. Millions of people worldwide have trachoma c. Trachoma is readily prevented by a chlamydial vaccine d. Progression of trachoma can be slowed by intermittent treatment with azithromycin e. Trachoma involves scarring of the conjuctiva, eylid deformities and eyelash injury to the cornea

c. Trachoma is readily prevented by a chlamydial vaccine

A woman who lives on a small farm is brought to the ER complaining of double vision and difficulty talking. Within the past 2 hours, she has had a dry mouth and generalized weakness. Last night she served home-canned green beans as part of the meal. She tasted the beans before they were boiled. None of the other family members are ill. On examination, there is symmetrical descending paralysis of the cranial nerves, upper extremities and trunk. The correct diagnosis is which of the following? a. Tetanus b. Strychnine poisoning c. Botulism d. Morphine overdose e. Ricin intoxication

c. botulism

A boy develops a severe sore throat. On examination, a grayish exudate (pseudomembrane) is seen over the tonsils and pharynx. The differential diagnosis of severe pharyngitis such as this includes group A streptococcal infection, Epstein-Barr virus (EBV) infection, Neisseria gonorrhoeae pharyngitis and diphtheria. The cause of the boy's pharyngitis is most likely a. A gram- negative bacillus b. A single stranded positive sense RNA virus c. A catalase-positive coccus that grows in clusters d. A club-shaped gram-positive bacillus e. A double stranded RNA virus

d. A club-shaped gram-positive bacillus

Listeria monocytogenes is frequently a foodborne pathogen because a. it can survive at 4C b. it survives under conditions of low pH c. it survives in the presence of high salt concentrations d. All of the above are correct

d. All of the above are correct

Which of the following foods is most frequently associated with infant botulism? a. Corn syrup b. Canned infant formula c. Liquid multivitamins d. Honey e. Jarred baby food

d. Honey

All of the following statements regarding Clostridium perfringens are correct EXCEPT a. It produces an enterotoxin b. It produces a double zone of hemolysis with blood agar c. Some strains are aerotolerant d. It is the most common cause of antibiotic associated diarrhea e. It can cause intravascular hemolysis

d. It is the most common cause of antibiotic associated diarrhea

A young boy has been playing with another child who develops Haemophilus influenzae meningitis. The boy's parents consult his pediatrician who says she is comfortable that the child will be fine because he has been fully immunized with the polyribitol ribose phosphate (PRP)- protein conjugate vaccine. For what reason is it necessary to immunize infants of 2 months to 2 years of age with polysaccharide-protein conjugate vaccines? a. The conjugate protein is diptheria toxoid and the goal is for the infant to develop simultaneous immunity to diptheria b. Infants 2 months to 2 years of age do not immunologically respond to the polysaccharide vaccines that are not conjugated to a protein. c. The conjugate vaccine is designed for older children and adults as well as infants. d. Maternal (transplacental) antibodies against Haemophilus influenzae are gone from the infant's circulation by 2 months of age e. None of the above

d. Maternal (transplacental) antibodies against Haemophilus influenzae are gone from the infant's circulation by 2 months of age (??)

The inhabitants of a group of small villages in rural sub Saharan Africa experienced an epidemic of meningitis. Ten percent of the people died (most of them younger than the age of 15 years). The microorganism that most likely caused the epidemic was a. Streptococcus agalactiae (group B) b. E. coli K1 (capsular type 1) c. Haemophilus influenza serotype b d. Neisseria meningitidis serogroup A e. West Nile virus

d. Neisseria meningitidis serogroup A

Skin diphtheria, as occurs in children in tropical areas, typically a. Does not occur in children who have been immunized with diphtheria toxoid b. Is clinically distinct from skin infections (pyoderma, impetigo) caused by Streptococcus c. Is also common in northern latitudes d. Results in protective antitoxin levels in most children by the time they are 6 - 8 years old e. Yields toxin mediated cardiomyopathy

d. Results in protective antitoxin levels in most children by the time they are 6 - 8 years old

The sputum from the 17-year old patient with cystic fibrosis is also plated on mannitol salt agar which turns yellow (from the base line pink) where white colonies of gram positive cocci are growing; the cocci are catalase positive and coagulase positive. The microorganisims growing on the MSA are a. Burkholderia cepacia b. Streptococcus pneumoniae c. Stenotrophomonas maltophilia d. Staphylococcus aureus e. Streptococcus pyogenes

d. Staphylococcus aureus

A 45-year-old man (who immigrated to the US 5 years ago) sustained a puncture injury to the lower part of his right leg when his rotary lawn mower threw a small stick into his leg. Six days later, he noticed spasms in the muscles of his right leg; on day 7, the spasms increased. Today, day 8- he had generalized muscle spasms, particularly noticeable in the muscles of his jaw. He was unable to open his jaw and came to the ER. In the ER, you see a man who is alert and lying quietly in bed. A door slams down the hall, and suddenly he has general muscle spasms with arching of his back. The correct diagnosis is which of the following? a. Botulism b. Anthrax c. Gas gangrene d. Tetanus e. Toxic shock syndrome

d. Tetanus

Dark field microscopy may be used to diagnose spirochetes in which of the following scenarios? a. To detect spirochetes in the CSF of a patient with tertiary syphilis b. To detect spirochetes in a suspicious lesion in the oral cavity in a patient with secondary syphilis. c. To detect spirochetes in the urine of a patient with suspected leptospirosis d. To detect spirochetes in the blood of a patient with a positive RPR result,, but no symptoms

d. To detect spirochetes in the blood of a patient with a positive RPR result,, but no symptoms

An 18 year old woman in rural Bangladesh develops profuse diarrhea. She has no symptoms other than the diarrhea and the manifestations of the fluid and electrolyte loss caused by the diarrhea. The most likely cause of her diarrhea is a. Campylobacter jejuni b. Enterotoxigenic E. coli c. Salmonella typhimurium d. Vibrio cholerae e. Shigella dysenteriae

d. Vibrio cholerae

During the El Nino years in the mid to late 1990's the waters of Puget Sound between Washington state and British Columbia warmed considerably. During this time many people who ate clams and oysters from these waters became ill with a disease characterized by explosive diarrhea and moderately severe abdominal cramps. The diarrhea was usually watery, but in some patients it was bloody. The diarrhea usually had an onset within 24 hours after eating the shellfish. Stool cultures typically yielded a pathogenic gram-negative bacillus. The microorganism of concern in this setting is a. Enterotoxigenic E. coli b. Vibrio cholerae c. Enterohemorrhagic E. coli d. Vibrio parahaemolyticus e. Shigella dysenteriae

d. Vibrio parahaemolyticus

All of the following are virulence factors associated with N gonorrhoeae except a. Pili b. Por c. Lipooligosaccharide d. Opa proteins e. A thick polysaccharide capsule

e. A thick polysaccharide capsule

A 19 year old man develops a cough and fever. A chest radiograph shows consolidation of the left lower lobe. A diagnosis of pneumonia is made. Which of the following bacteria is a frequent cause of community acquired pneumonia? a. Legionella pneumophila b. Chlamydia pneumoniae c. Streptococcus pneumoniae d. Mycoplasma pneumoniae e. All of the above

e. All of the above

An 18 year old sexually active woman develops left lower quadrant pain and fever. On pelvic examination she has tenderness in the left adnexa and a mass suggestive of an uterine tube abscess is palpated. The patient is diagnosed with pelvic inflammatory disease. Which of the following bacteria is considered to be a common cause of PID? a. Bacillus cereus b. Haemophilus influenzae c. Neisseria subflava d. Mycoplasma pneumonia e. Chlamydia trachomatis

e. Chlamydia trachomatis

A man has a major soft tissue injury and an open fracture of his right leg after a motorcycle accident. One day later, he has a temperature of 38*C, increased heart rate, sweating and restlessness. On examination, the leg is swollen and tense, with thin, dark, serous fluid draining from the wounds. The skin of the leg is cool, pale, white and shining. Crepitus can be felt in the leg. His hematocrit is 20% (-50% of normal), and his circulating hemoglobin is normal. His serum shows free hemoglobin. Which of the following microorganisms is the most likely cause of this infection? a. Clostridium tetani b. Staphylococcus aureus c. Escheria coli d. Bacillus anthracis e. Clostridium perfringens

e. Clostridium perfringens

The primary mechanism in the pathogenesis of the boy's disease (question 15) is a. A net increase in intracellular cyclic adenosine mono-phosphate b. Action of pyrogenic exotoxin (a superantigen) c. Inactivation of acetylcholine esterase d. Action of enterotoxin A e. Inactivation of elongation factor 2

e. Inactivation of elongation factor 2 (?)

Long-term carriage and shedding is the most likely to occur after gastrointestinal infection with which of the following species? a. E. coli O157:H7 b. Shigella dysenteriae c. Vibrio cholerae d. Campylobacter jejuni e. Salmonella typhi

e. Salmonella typhi

8. Which of the following statements about tetanus and tetanus toxoid is correct? a. Tetanus toxin kills neurons. b. Tetanus toxoid immunization has a 10% failure rate c. The mortality rate of generalized tetanus is less than 1% d. Double vision is commonly the first sign of tetanus e. Tetanus toxin acts on inhibitor interneuron synapses

e. Tetanus toxin acts on inhibitor interneuron synapses

A 20 year old woman presents with a 2 cm ulcer on her labia majora. The lesion has a raised border and is relatively painless. What is the most likely pathogen? a. Adenovirus infection b. Papillomavirus infection c. Neisseria gonorrhoeae infection d. Chlamydia trachomatis cervicitis e. Treponema pallidum infection

e. Treponema pallidum infection

A 59 year old man comes to the ER in the afternoon because of acute swelling and pain in his right leg. Earlier that morning, he had been working on a small sport fishing boat in an estuary in the Gulf Coast of Texas. While walking around the boat in shallow water, he scratched his leg, breaking the skin at the site of the current pain and swelling. He was not wearing boots. About 1 hour after the injury the scratch became red and markedly swollen. The skin was red and tender. There was serous drainage from the wound which had ulcerated and was now much enlarged. Near the wound, bullae were forming. The largest approximately 2.5mm in diameter. The most likely cause of this medical emergency is a. Staphylococcus aureus b. Streptococcus pyogenes c. Clostridium perfringens d. E. coli e. Vibrio vulnificus

e. Vibrio vulnificus

A young woman presents with a 3 day history of low grade fever and headache. Examination reveals enlarged and slightly tender lymph nodes near her left elbow and the left axilla. Approximately 2 weeks earlier she had visited a friend whose cat had scratched her on the left arm. The site later developed a reddish papule. Which of the following statements about cat scratch disease is most correct? a. The diagnosis is based on a suggestive history and physical examination b. The diagnosis is based on negative routine bacterial cultures of pus aspirated from the involved lymph nodes c. the disease is usually self limited in immunocompetent people. d. the etiologic agent is bartonella henselae e. all of the above

e. all of the above

Which of the following animals is the source of Leptospira interrogans? a. Cattle b. Dogs c. Mice d. Rats e. Swine f. All of the above

f. All of the above

Which of the following is not a recognized virulence factor for Bordetella pertussis? a. Heat-labile toxin b. Filamentous hemagglutinin c. Tracheal cytotoxin d. Pertussis toxin e. Dermonecrotic toxin

unclear ???