honeyy

Gram-negative Gram-positive Streptococcus piogenes= Lancefield Group A

Which of the morphological and tinctorial properties are typical for streptococci?

chainlike Gram-positive having thick cell wall

Which of the culture properties are characterized of S.aureus?

Beta-hemolytic colony golden yellow colony selective medium is egg salt agar

Which of the biological properties are characteristic of S.aureus?

coagulase-positive hemolytic protein M

Which of the general properties are characterized of staphylococci?

family Micrococcaceae Genus staphylococcus

Which of the cultural properties are characteristic of staphylococci?

facultative anaerobe selective medium is egg salt agar T-37C

Which of the biological properties are characterized of staphylococci?

catalase positive facultative anaerobic Gram-positive

Which of the morphological and tinctorial properties are characterized of staphylococci?

Gram-positive grapelike clusters having thick cell wall

Which of the following structures have an enveloped virus ?

envelope nucleocapsid spikes

Which of the following structures have a naked virus ?

capsid capsomers DNA and RNA

Which of the following properties concerning of the H-antigen of bacteria is correct ?

flagella heat lable protein flagellin

Which of the following properties concerning of the K-antigen of bacteria is correct ?

capsule Escape from the phagocytosis polypeptide or polysaccharide

Which of the following properties concerning of the O-antigen of bacteria is correct ?

heat stable part of the cell wall polysaccharide portion of the LPS of the gram-negative bacteria

Which of the following structure of bacteria known as O,-H,-K- antigens ?

capsule cell wall flagella

Which of the following diseases can be prevented by MMR vaccine ?

Measles Mumps Rubella

Which of the following diseases can be prevented by DPT vaccine ?

Diphtheria Tetanus Whooping cough

Which of the following bacteria release neurotoxin?

Clostridium botulinum Clostridium difficile ( Toxin B) Clostridium tetani

Which of the following bacteria release enterotoxin?

Enterotoxigenic E. coli Staphylococcus aureus Vibrio cholerae

Ureplasma. urealyticum is part of the normal genital flora of both men and women. It is found in about 70% of sexually active humans. It had also been associated with a number of diseases in humans. All are features of urealyticum except

Salpingitis

A 23 year old male has unprotected sexual intercourse with commercial sex worker. Two weeks later he developed a painless, indurated ulcer on the glans that exuded clear serums on pressure inguinal lymph node in both groins were enlarged and non tender. Which one of the following is the most appropriate test to diagnose infection of this patient?

Dark field microscopy of ulcer discharge

A man present to STD clinic with urethritis and urethetral discharge. Gram stain show numerous pus cell but no microorganism. Culture is negative on blood media. Which of the following is most likely causative agent?

Chlamydia trachomatis

A male patient with symptoms of urethritis. Examination reveals only pus cells without any organism. Which of the following is most likely causative agent?

Chlamydia trachomatis

A patient complained of chills and fever following a louse bite 2 weeks before. He had rashes all over the body and was delirious at the time of presentation to the hospital and subsequently went into coma. A provisional diagnosis of vasculitis due to rickettsia infection was made. Which one of the following can be the causative agent

Rickettsia prowazekii

A 28 year old lady presented with headache, Kernig’s sign positive, culture show gram positive bacilli. Which of the following is the most probable organism ?

Streptococcus pneumonia

A 3 week old child presented to the pediatrician with meningitis. A presumptive diagnosis of late onset of perinatal infection was made. The CSF culture was positive for gram-positive bacilli.. Which of the following characteristics of this bacteria would be helpful in differentiating it from other bacterial agents?

Motility at 25 o C

Culture of pathogen: on agar frosted glass appearance, colony microscopy Medusa head appearance, gelatin stab –inverted fir tree appearance, string of pearls appearance on culture medium with penicillin Which of the bellow mentioned pathogen is it?

Bacillus anthracis

A 12-year-old girl was playing soccer when she began to limp. She has pain in her right leg and right upper thigh. Her temperature is 38.9°C (102°F). X-ray of the femur reveals that the periosteum is eroded, suggestive of osteomyelitis. Blood culture yields gram-positive bacteria. The most likely etiologic agent is which of the following?

Staphylococcus aureus

An infant had high grade fever and respiratory distress at the time of presentation to the emergency room. The sample collected for blood culture was subsequently positive showing growth of alpha-hemolytic colonies. Gram-positive capsulated cocci in pairs. Which of the screening tests can be used for identification?

Optochin

In a patient of orbital cellulitis, microorganism on culture show greenish colonies and optochin sensitivity. What is the most likely microorganism?

S. pneumonia (pneumococcus )

A 12 yr old child presents with fever and cervical lymphadenopathy. Oral examination shows a grey membrane on the right tonsil extending to the anterior pillar. Which of the following medium will be ideal for the culture of throat swab for a rapid identification of the pathogen?

Loeffler’s serum slope

In a completely and adequately immunized child against diphtheria, the throat swab was collected. It showed the presence of C.diptheriae organisms on Albert staining. These organisms can have one of the following properties on further processing:

It can grow on potassium tellurite media

A 10 yr old boy following a road traffic accident presents to the casualty with contaminated wound over the left leg. He has received his complete primary immunization before preschool age and received a booster of DT at school entry age. All of following can be done except:

Injection of human antiserum

A patient of acute lymphocytic leukemia with fever and neutropenia devlops diarrhea after administration of amoxicillin therapy , which of the following organism is most likely to be the causative agent:

Clostridium difficle

An 18yr old male presented with acute onset descending paralysis of 3 days duration. There is also a history of blurring of vision for the same duration. On examination, the patient has quadriparesis with areflexia. Both the pupils are non-reactive. The most probable diagnosis is:

Botulism

A person has received complete immunization against tetanus 10 yеar ago. Now he presents with a clean wound without any lacerations from an injury sustained 2.5 hour ago. He should now be given:

Full course of tetanus toxoid

A moderately contagious skin disease that occurs primarily in children 5 to 9 years of age that is caused by the rubella virus, which is acquired by droplet inhalation into the respiratory system;

German measles

A skin eruption that produces a rose-colored rash in infants. Caused by the human herpesvirus the disease is short-lived and characterized by a high fever of 3 to 4 days’duration. What is it?

Roseola infantum

A bacterial infection transmitted by contaminated food, water, milk, or shellfish. The causative organism is Salmonella typhi,which is present in human feces. A bacterial exotoxin that has been modified so that it is no longer toxic but will still stimulate antitoxin formation when injected into a person or animal. What is the infection?

Typhus fever

A preparation of either killed microorganisms; living, weakened (attenuated) microorganisms; or inactivated bacterial toxins (toxoids). It is administered to induce development of the immune response and protect the individual against a pathogen or a toxin. What is it?

Vaccine

A test for the diagnosis of typhus and certain other rickettsial diseases In this test, the blood serum of a patient with suspected rickettsial disease is tested against certain strains of Proteus vulgaris(OX-2, OX-19, OX-K) The agglutination reactions, based on antigens common to both organisms, determine the presence and type of rickettsial infection.. What is the test

Weil-Felix reaction

A test involving agglutination of typhoid bacilli when they are mixed with serum containing typhoid antibodies from an individual having typhoid fever; used to detect the presence of Salmonella typhi and S. paratyphi. What is the test?

vidal test

A disease caused by staphylococci that produce toxin. The skin becomes red (erythema) and sheets of epidermis may separate from the underlying tissue. Which of toxins produced by S.aureus causes “scalded skin” syndrome?

Exfoliatins.

A type of food poisoning caused by ingestion of improperly stored or cooked food in which Staphylococcus aureus has grown. The bacteria produce exotoxins that accumulate in the food. Which of toxins produced by S.aureus causes food poisoning?:

Enterotoxins.

Brucellais pathogenic for humans and animals. Which one of the following statements best characterizes this organism?

It causes spontaneous abortion and has tropism for placental tissue due to the

Streptococcus pyogenesis a toxigenic bacterium causing a variety of diseases. Which of the following statements best characterizes this organism?

It secretes erythrogenic toxin that causes the characteristic signs of scarlet feve r

Francisella tularensisis the bacterium that causes tularemia, a disease not uncommonly seen in hunters. Which one of the following statements best characterizes this bacterium?

It requires cysteine for growth

Bordetella pertussis and B. parapertussisare similar and may be isolated together from a clinical specimen. Bordetella pertussisis a Gram-negative rod that causes severe respiratory disease. Which one of the following statements best characterizes this microorganism?

It produces at least one protein toxin consisting of two subunits, A and B, that cause severe spasmodic cough usually in children

The skin flora differs as a function of location. Skin adjacent to mucous membranes may share some of the normal flora of the gastrointestinal system. Which of the following is the predominant organism on skin commonly seen as a blood culture contaminant?

S. epidermidis

Brucella abortus,one of the three species causing brucellosis, a possible bioterrorism agent, is best described by which of the following statements?

Typically infects cattle, requires 5 to 10% carbon dioxide for gro wth, and is inhibited by the dye

Bacteria cause disease in a number of ways. One mechanism of pathogenesis is the secretion of potent protein toxins. All the following diseases are caused by microbial protein toxins, but one toxin has been used for a variety of maladies. Which one of this is possible?

Botulism

Some organisms originally thought to be vibrios, which has its reservoir in birds and mammals and causes gastroenteritis in humans such as C. jejuni, have been reclassified. C. jejuni, C. jejuniis best described as

Cause of gastroenteritis; reservoir in birds and mammals, optimal growth at 42°C +

Vibrios are shaped like curved rods, and infections more common than cholera may be caused by a variety of curved-rod bacteria. V. cholerae,the causative agent of cholera, is best described as

“String-test”-positive isolate; three serotypes—Ogawa (AB), Inaba (AC), Hikojima (ABC )

Pneumonia that affects persons in health care facilities, such as hospitals, is called hospital-acquired pneumonia. Which one is frequently implicated in nosocomial infections and is an important cause of community- acquired pneumonia in adults

Klebsiella pneumonae

Listeria is found in the environment but is not normal fecal flora in humans. Infection with Listeriais more common in the summer months.The most frequent source of infection with L. monocytogenesis through which of the following?

Raw milk

A premature neonate suffers pneumonia and sepsis. Sputum culture on blood agar plate yields pinpointed β-hemolytic colonies. Which of the following is a simple test to determine whether the organism is S. agalactiae or L. monocytogenes (these two organisms are important neonatal pathogens)?

Catalase test

A 65-year-old diabetic man presents to the emergency room with a severe productive cough producing thick bloody sputum resembling a “currant-jelly” like appearance. Culture using MacConkey agar reveals pink colonies, with large mucoid colonies on routine laboratory media. Which of the following organisms is most likely responsible for this patient’s pneumonia?

C. Klebsiella pneumonia

Chlamydia are gram-negative obligate intracellular parasites with a unique life cycle. It is coccoid in morphology and is very small, usually about 350 nm in diameter. C. trachomatiscan be distinguished from C. psittaci by which of the following criteria?

C. trachomatis is sensitive to sulfonamides

A man with chills, fever, and headache is thought to have “atypical”pneumonia. History reveals that he raises chickens and that approximately 2 weeks ago he lost a large number of them to an undiagnosed disease. The most likely diagnosis of this man’s condition is

Ornithosis (psittacosis )

A farmer rearing sheep, presented with complaints of fever and weakness for the last one month .There is generalized lymphadenopathy. There was also associated hepatomegaly, Biopsy of liver showed non-caseating granuloma. There are likely due to infection with?

Brucella melitensis

A farmer presenting with fever off and on for the past 4 years was diagnosed to be suffering from chronic Brucellosis. All of the following serological tests would be helpful in the diagnosis at this state except?

Widal test

A veterinary doctor had pyrexia of unknown origin. His blood culture in special laboratory. Media was positive for gram negative short bacilli which were oxidase positive. Which one of the following is the likely organism grown in culture?

Brucella spp.

A girl from Shimla presented with fever, malaise and axillary/inguinal lymphadenopathy and organism shows stalactite growth on culture. Which of the following is the causative agent?

Yersinia pestis

A man after skinning a dead animal, developed a pustule on his hand. A smear prepared from the lesion showed the presence of gram positive bacilli in long chains which were positive for McFadyean”s reaction. The most likely etiological agent is?

Bacillus anthracis

Recently, there have been sensational media reports of patients infected with invasive, “flesh-eating”bacteria that spread rapidly through the tissues. This necrotizing fasciitis is usually caused by

Group A streptococci

E. coli causes disease by a variety of different methods. Which one of the following E. colitypes is characterized by the presence of LT (heat-labile) and ST (heat-stable) proteins?

Enterotoxigenic (ETEC)

A 2-year-old infant is brought to the emergency room with hemolytic uremic syndrome and thrombocytopenia. Which one of the following bacteria would most likely be isolated from a stool specimen?

coli0157/H7

One of the most common sexually transmitted diseases that may lead to cervical carcinoma is caused by which of the following viruses?

Adenovirus

Your patient has a brain abscess that was detected I month after a dental extraction. Which one of the following organisms is MOST likely to be involved?

Anaerobic streptococci

Which of the following procedures or clinical signs is most specific for the diagnosis of infectious mononucleosis caused by the Epstein-Barr virus?

Heterophile antibodies or VCA (viral capsid antibody ).

The latest and most effective therapy for AIDS patients includes azidothymidine (AZT), dideoxyinosine (DDI) and saquinavir or similar agents. Which of the following viral processes inhibited after using of these three drugs?

Reverse transcriptase, protease

An HIV-positive patient asks you if you can tell him the chances of him progressing to symptomatic AIDS. Which one of the following tests would be most useful?

HIV RT PCR

A 65-year-old man develops dysuria and hematuria. A Gram stain of a urine sample shows gram-negative rods. Culture of the urine on Eosin-methylene blue (EMB) agar reveals lactose-negative colonies with evidence of swarming motility. Which one of the following organisms is MOST likely to be the cause of his urinary tract infection?

Pseudomonas aeruginosa

A patient with a peptic ulcer was admitted to the hospital and a gastric biopsy was performed. The tissue was cultured on chocolate agar incubated in a microaerophilic environment at 37°C for 5 to 7 days. At 5 days of incubation, colonies appeared on the plate and were curved, Gram-negative rods, oxidase-positive, urease- positive. The most likely identity of this organism is

Helicobacter pylori

A culture of skin lesions 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 test to be negative, which one of the following organisms would you MOST probably have isolated?

Streptococcus pyogenes

A 60-year-old man with a chronic cough, bloody sputum, and marked weight loss is diagnosed as having tuberculosis. A “serpentine-like” colonial morphology is noted on citrated blood medium. This latter finding is caused by which of the following factors?

Cord factor

A 33-year-old nurse suffered a needle stick injury. The patient used illicit intravenous drugs. One month later, the nurse develops jaundice. Which of the following findings would implicate hepatitis B as the etiology?

Positive antihepatitis B-core antibody

This virus causes a mononucleosis-like syndrome caused by a latent herpesvirus; it is often a congenital infection. Large amounts of the virus are excreted in the urine; thus, urine becomes the fluid of choice for diagnosis of this disease. Which one is the most likely pathogens?

Cytomegalovirus

Infectious mononucleosis is an acute disease most commonly seen in younger people. It is characterized by a proliferation of lymphocytes, lymph node enlargement, pharyngitis, fatigue, and fever. Infection in young children is usually either asymptomatic or characteristic of an acute upper respiratory infection. Diagnosis is usually made by a positive heterophilic antibody test. Which one is the most likely pathogens?

Epstein-Barr virus

Which of the following is found within the nuclei of infected hepatocytes and not usually in the peripheral circulation?

HBcAg

There are several groups of the HBV markers for diagnostic./Which one of the following markers is closely associated with HBV infectivity and DNA polymerase activity?

HBeAg

Advances in the serodiagnosis of viral hepatitis have been dramatic, and the findings of specific viral antigens have led to further elucidation of the course of infections. Which of the following may be the only detectable serological marker during the early convalescent phase of HBV infection (window phase)?

HBcAg

Which of the following markers is usually the first viral marker detected after hepatitis B infection?

HBsAg

An obstetrician sees a pregnant patient who was exposed to rubella virus in the eighteenth week of pregnancy. She does not remember getting a rubella vaccination. The best immediate course of action is to

Order a rubella antibody titer to determine immune status

A nurse develops clinical symptoms consistent with hepatitis. She recalls sticking herself with a needle approximately 4 months before after drawing blood from a patient. Serologic tests for HBsAg, antibodies to HBsAg, and hepatitis A virus (HAV) are all negative; however, she is positive for IgM core antibody. The nurse

Is in the “window”(after the disappearance of HBsAg and before the appearance of anti-HBsAg)

A 50-year-old homeless alcoholic has a fever and is coughing up I cup of green, foul smelling sputum per day. You suspect that he may have a lung abscess. Which one of the following pairs of organisms is MOST likely to be the cause?

Fusobacterium nucleatum and Pcptostreptococcus intermedius

Yersinia pestis, the causative agent of plague, is enzootic in the United States west of the one-hundredth meridian. Human plague can be bubonic or pneumonic. Which of the following is most accurate to the primary epidemiologic difference between the two clinical forms of plague?

Route of infection

Cholera is a toxicogenic dysenteric disease common in many parts of the world. What would be expected in the treatment of patients who have cholera after using of a drug that inhibits adenyl cyclase?

Block the action of cholera toxin

The mechanism of action of the exotoxin produced by C. diphtheria can be characterized by which of the following?

Inhibits protein synthesis via EF-2 adenosine diphosphate (ADP ) ribosylation.

A 3-year-old child presents at the physician’s office with symptoms of coryza, conjunctivitis, low-grade fever, and Koplik’s spots. The causative agent of this disease belongs to which group of viruses?

Paramyxovirus

A hospitalized patient developed severe diarrhea and pseudomembranous colitis within 5 days after antibiotic therapy was initiated. The severe diarrhea and pseudomembranous colitis occurred as a result of which of the following?

enterotoxin A , cytotoxin B

A 20-year-old college student develops diarrhea that lasts for approximately 1 week. Stool cultures reveal a motile, microaerophilic gram-negative rod that is isolated by incubation at 41°C (105.8°F) on medium containing antibiotics. This organism is most likely to be which of the following?

D.Campylobacter jejuni.

Bacillus anthracisis unique to other bacteria. It is the only bacteria to possess which of the following?

A polypeptide capsule

Delta hepatitis only occurs in patients who also have either acute or сhronic infection with hepatitis B virus. The delta agent is

An incomplete RNA virus

Viruses are spherical , 80 to 120 nm in diameter, multipartite genome of single-stranded antisense RNA in seven or eight segments. The envelope carries a hemagglutinin and a neuraminidase, Which of the following diseases can cause?

Influenza

A 70-year-old nursing home patient refused the influenza vaccine and subsequently developed influenza. She died of acute pneumonia 1 week after contracting the “flu.”The most common cause of acute post influenzal pneumonia is

Staphylococcus_ aureus

An outbreak of sepsis caused by Staphylococcus aureus has occurred in the newborn nursery. You are called upon to investigate. According to your knowledge of the normal flora, what is the MOST likely source of the organism?

Throat , Nose

There are millions of cases of leprosy (Hansen’s disease) worldwide, but predominately in Asia and Africa. The clinical spectrum of Hansen’s disease is best characterized by

Peripheral neuritis.

An experimental compound is discovered that prevents the activation of adenyl cyclase and the resulting increase in cyclic AMP. The toxic effects of which of the following bacteria might be prevented with the use of this experimental compound?

Vibrio cholera ,

An outbreak of staphylococcal infection involving umbilical cords of seven newborn babies was reported in the nursery. Bacteriologic survey reveals that two nurses have a large number of S. aureus in the asopharynx. What test should be performed to determine whether these nurses may have been responsible for the outbreak?

Bacteriophage typing

L. monocytogenes causes a variety of diseases, including food poisoning. Listeria are small, Gram-positive, motile rod-shaped bacteria. Which of the following best describes these microorganisms?

Listeria are facultative intracellular pathogens

Virtually all prokaryotic cells (bacteria, both Gram-positive and Gram-negative) contain peptidoglycan as well as specific enzymes for its synthesis. All of the following statements concerning Gram-positive and Gram-negative bacteria are true except:

Both Gram-positive and Gram-negative bacteria contain significant amounts of teichoic

An isolate from a wound culture is a Gram-negative rod identified as Bacteroides fragilis. Anaerobic infection with B. fragilisis characterized by

A foul-smelling discharge .

A sputum sample was brought to the laboratory for analysis. Gram stain revealed the following: rare epithelial cells, 8 to 10 polymorphonuсlear leukocytes per high-power field, and pleomorphic Gram-negative rods. As the laboratory consultant, which of the following interpretations should you make?

The appearance of the sputum is suggestive of Haemophilus pneumonia .

Your patient is a 70-year-old man who under went 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?

Bacteroides fragilis. and Klebsiella pneumonia .

Five days ago a 65-year-old woman with a lower urinary tract infection began taking ampicillin. She now has a fever and severe diarrhea. Which one of the listed organisms is MOST likely to be the cause of the diarrhea?

Clostridium difficile

Cholera is an infectious disease of the gastrointestinal tract caused by the Vibrio cholerae serogroup 01 and 0139 All of the following are true about V. cholerae except:

Cannot grow in ordinary media

Mechanism of action of the Neurotoxin – prevents transmission of nerve impulses causing FLACCID PARALYSIS .Which of the listed bacteria release that Neurotoxin

Clostridium botulinum

Neurotoxin blocks nerve impulses to muscle contraction pathway that results in uncontrollable muscle contraction. Which of the listed bacteria release described Neurotoxin?

Clostridium tetani

Enterotoxin is kind of the Exotoxin. Enterotoxin causes secretion of large amounts of fluids and electrolytes that results in diarrhea .Which of the listed bacteria release Enterotoxin?

Enterotoxigenic Escherichia Coli

Enterotoxin is kind of the Exotoxin. Enterotoxin causes secretion of large amounts of fluids and electrolytes that results in diarrhea .Which of the listed bacteria release Enterotoxin?

Vibrio Cholerae

Subterminal spores are found in:___ and and food poisoning with consumption of the canned food

Clostridium botulinum

Symptoms of the disease can occur 12-36 hours (several hours to 8 days) after ingestion of contaminated food All occurs in botulism except:

Rashes and fewer

Botulism is food poisoning caused by the exotoxin that is secreted by Clostridium botulinum The following statements are true regarding botulism except:

Infant botulism is caused by ingestion of performed toxin

Botulism is a rare and potentially fatal illness caused by a toxin produced by the bacterium Clostridium botulinum All of the following statements about Botulism are true except:

Botulism is sexual transmitted

Which of the following statement of the bacterioscopic of the wound is possible in patient with diabetic food syndrome caused by S.aureus?

Gram-positive grape like catalase positive cocci

Which of the following statement of the bacterioscopic report of the CSF is possible in neonatal meningitis caused by Escherichia coli?

Gram-negative catalase-positive rod shaped bacteria

Which of the following report of the bacterioscopic examination of the CSF is possible in neonatal meningitis caused by Streptococcus agalactiae?

Gram-positive cnain like catalase negative cocci

Which of the following report of the bacterioscopic examination of the CSF is possible in neonatal meningitis caused by Listeria monocytogenes ?

gram- positive, catalase-positive, rod shaped bacteria

The following gram- positive, catalase-positive, rod shaped bacteria are most often associated with acute neonatal meningitis :

Listeria monocytogenes

The following gram-negative, catalase-positive, oxidase-negative rod shaped bacteria are most often associated with acute neonatal meningitis :

Escherichia coli

Which of the following report of the bacterioscopic examination of the CSF shows: in meningococcal meningitis?

Gram-negative Diplococci, in pus cell

The following gram-positive, catalase-negative spherical shaped bacteria are most often associated with acute neonatal meningitis:

Streptococcus agalactiae

In December, 1992, a large epidemic of cholera began in Bangladesh, and large numbers of people have been involved. The organism has been characterized as V. cholerae Bengal. Which of the serotypes of V. cholerae caused cholera in Bengal?

0:139

Vibrio cholerae is a comma-shaped, gram-negative bacterium . Which of the following statement is true about Vibrio cholera

V. cholerae 0-139 cause cholera in Bengal

The endotoxin of the following gram – negative bacteria does not play any part in the pathogenesis of the natural disease:

Vibrio cholera

Culture properties of the Vibrio cholera. Which of the mentioned culture media is Selective media Vibrio cholera?

TCBS agar

Cholera is an infectious disease of the gastrointestinal tract caused by the Vibrio cholerae serogroup 01 and 0139 All of the following statement about cholera are true except:

Synthesize neuraminidase

V. cholerae produce enterotoxin/ In the small intestine, cholera toxin acts by:

activates the adenylate cyclase enzyme

Symptoms of the disease can occur 12-36 hours (several hours to 8 days) after ingestion of contaminated food All occurs in botulism except:

Diarrhea

Clostridium tetani, is present everywhere in the environment—in soil, in dust, on window ledges and floors. What is thrue about Clostridium tetani

Produces exotoxin ( tetanospasmin)

Lecithinase test or naglers reaction is a biochemical test used to identify organisms which liberate phospholipases (lecithinases). Nagler’s reaction is shown by:

C. perfringens

Many Gram negative rods are rod-shaped bacteria that usually are found as single individual cells. This group is facultatively anaerobic, and includes many pathogens. Which of the listed below pathogens is gram-negative rod that exhibits bipolar staining, posseses a capsule?

Yersinia pestis

Plasmids are extrachromosomal genetic material of the microorganisms.Which of the following is most accurate to function of the F-plasmids?

ability to conjugation

The phase-contrast microscope converts variations in the refractive index and density of cells into changes in light intensity and thus makes colorless, unstained cells visible. Which of the following is the best to describe Phase - contrast microscopy:

uses a special condenser to enhance differences in the refractive indexes of the cell parts and its surroundings

Treponema pallidum possesses two kinds of antigens. Which of the following tests is carried out with non-specific antigens (cardiolipin) for laboratory diagnostic of syphilis?

Complement fixation test (Vasserman reaction ).

Vaccination for this hepatic disease is with viral surface antigen and usually provides immunity.

Hepatitis B

There are some differences between prokaryotic and eukaryotic cell structure.Which one of the statements is the MOST accurate comparison of human, bacterial, and fungal calls?

Human and fungal cells have similar ribosomes, whereas bacterial ribosomes are different

This technique can be used to determine the number of microbes/mL or microbes/gram in a specimen. It has the advantage of not requiring previously prepared plates, and is often used to assay bacterial contamination of foodstuffs

Pour plate

Gram staining is the differential method to identify gram-negative and gram-positive bacteria The Gram stain differentiates between bacteria based on the composition of their _________.

Cell Wall

Found in some bacterial cells, this additional outer covering protects the cell when it is engulfed by other organisms, assists in retaining moisture, and helps the cell adhere to surfaces and nutrients. What is it?

Cell Wall

Bacteria are cultured and found to be Gram-negative diplococci that grow on chocolate agar r. Which of the following is the most likely?

Neisseria

Pili are hair-like structures on the surface of the bacterial cells. There are 2 types of pili, sex and general. Which of the following is the most likely to the sex pili?