Bacteriology Finals Exams Rationalization

Which of the ff. Is correct about minimal bactericidal concentration?

The lowest concentration of drug that achieves 99.9% of killing

Which of the ff. describe the minimal inhibitory concentration?

The lowest concentration of an antimicrobial that will inhibit the visiblility of microorganism under standard conditions

The depth of Mueller Hinton agar needed for EXP

4 mm

In broth dillution test. The controls should be

Growth in growth control, no growth in sterility control

The zone of inhibition means which of the following?

The area of no growth around an antibiotic test in kirby bauer test

Which of the following procedures measures the zone of inhibition of bacterial growth around antimicrobial discs under standard conditions

Disk diffusion

A reliable test for distinguishing staphylococcus aureus from other Staphylococci is

Coagulase

The gram staining examination from a black culture bottle shows dark blue spherical organisms in clusters, the growth on sheep blood agar shows small brown, pale yellow colonies. Further test should include

Catalase production and coagulase present

A beta-hemolytic catalase positive, gram positive coccus is coagulase negative by the slight coagulase test. Which of the following is the most appropriate action in identification of this organism?

Do a tube coagulase test to confirm the slide test

The most critical distinction between staphylococcus aureus and other staphylococcus is

Do a tube coagulase test to confirm the slide test

How many hours after eating contaminated food do initial symptoms of staphylococcus food poisoning typically occurred?

2-6 hours

A yellow colony from a wound culture tested catalase positive and coagulase negative. The organism stain has gram positive cocci in clusters. Which of the ff. tests would differentiate between in coagulase negative staphylococcus and micrococcus

Furazolidone susceptibility

A gram-positive coccus isolated from a blood culture has the following characteristics:

Optochin susceptibility: negative

Bacitracin susceptibility: negative

Bile esculin hydrolysis: negative

Hippurate hydrolysis: positive

Catalase: negative

Streptococcus agalactiae

A beta-hemolytic streptococci that is bacitracin sensitive and count negative

Group A

Streptococcus pneumoniae can be differentiated best from the very dense group of streptococci by

Bile solubility

Which of the following would best differentiate streptococcus agalactiae from streptococcus pyogenes.

hydrolysis of sodium Hippurate

The symptoms in scarlet fever are due to

Pyrogenic toxin

A 54 year old male has a history of a mitral valve replacement 18 months prior to admission, he presented to the emergency room with fever and chills. Two days after he saw his dentist for a root canal, he says he did not take prophylactic antibiotic prior to the procedure but did take them the next day. Black cultures are drawn and two out of four bottles are positive for gram-positive cocci in chains. The blood cultures are subcultures to sheep blood agar with an optochin disk. Growth on the plate shows alphalytic colonies that are resistant to optochin. A catalyst's test is negative. The bile esculin test is positive, but the PYR test is negative and the isolate cannot grow in the presence of 6.5% sodium chloride, the correct identification of this organism is

Streptococcus bovis

The presence of one to nine AFB per field on fusion staining is reported as

\+3

Jimboy the seven year old grandson of a known tb case was sent to the local health centre for tuberculin skin testing. He and his parents with four other siblings lived together with a grandfather. What is the level of incubation expected if Jimboy were to be reactive to the skin test?

greater than or equal to five mm

Which of the following drugs is considered to be more toxic and less efficient to the patient, but is given in cases of treatment failure or multidrug resistance

ethionamide

What is the characteristic type of necrosis seen in tuberculosis?

caesation necrosis

A scotochromogen

Develops pigment when growing in the dark

What does a positive tuberculin reaction signify?

patient had infection in the past

The most cost efficient and routinely used differential staining method in microbiology laboratory.

Gram staining

CSF urine samples and bronchial Alveolar lavage are made in the smears for microbiology evaluation. In which of these techniques

dropped in the center of A premarked glass slide

A Flagellum stain which makes use of alcoholic crystal violet solution as primary stain and Aluminum potassium sulfate as mordant

Difco’s spot test

Which of the following statements best explains the staining characteristic of Gram positive organism

Gram positive cell walls contains disaccharides and amino acid ; acids are insoluble in acetone alcohol causing openings in their cell wall to lock trapping The crystal violet iodine complex

The Infected materials collected from cotton swabs are processed In the microbiology laboratory, always in duplicate. What is the reason behind this criteria?

to establish consistency in the contents of the received sample

a sputum sample submitted in the laboratory revealed one solid granular material. to better evaluate the contents of this granular material. Which of the following techniques is the most appropriate procedure to follow?

granule is removed from the sputum material and freshed out using two clean glass slides

What is responsible for the red color of acid class organisms?

Thick peptidoglycan layer with intact hydroxyl acid

What is the action of a prokaryote flagella?

simple flagella which moves by Rotary Action

Who refuted the idea of spontaneous generation by showing that rotting meat carefully kept from flies will not produce maggots

Francesco Redi

Prokaryotes reproduce sexually. Eukaryotes on the hand reproduce asexually only. True or False

Both are false

In the degradation phase of the bacterial growth, there is an increase in the number of dead bacteria, while in the exponential case the bacteria is most susceptible to antimicrobials. True or False.

Both are true

The starting carbohydrate in the pentose phosphate pathway is glucose. In this pathway there is high yield of ATP

first statement is true, second statement is false

What cell appendages are used for the adhesion of the bacteria to the host cell.

somatic pili

Olive complained to the physician of burning sensation when urinating and frequent urination for the past few days. A urinalysis and urine culture were immediately requested in the laboratory. Urinalysis showed a cloudy urine, a positive nitrate test. After five days, the result of the urine culture was released and indicated approved of 10 square CFU for ml, which of the following statements best interprets the urine culture result?

possible Escherichia coli or Staphylococcus saprophyticus infection

Which of the following are correct with regards?

Statement one: Midstream clean catch urine is a gold standard for urine culture

Statement two: specimens from catheter bags are acceptable. Statement three: the growth of 10^3 CFU/mL of urine is significant Statement four: The growth of 10^2 CFU/mL of urine is significant for sexually active young females. So which of the statements are correct with regards to culture?

Statement 4

Sodium polyanethol sulfonate acts as an anticoagulant in a blood culture. It also acts to remove antimicrobials. True or False.

First statement is true, second statement is false

What is the bacterial growth phase In the BaCT alert system, once carbon dioxide is detected?

Exponential phase

Which of the following statements are correct when collecting sputum specimens?

Statement 1 - collect on 3 separate days.

Statement 2 - Greater than 10 epithelial cells or LPO is accepted.

Statement 3 - must be decontaminated and digested

statement 4 - 20 fields are observed under OIO.

Statement 1 and 3

A 25 yr old man with HIV went to the ER and reported numbness and weakness in his right leg for 7 months. Upo physical examination, Kaposi’s sarcoma lesions were observed. Lumbar tap was performed and 4 tubes were connected. The specimen must then received in the laboratory. Which of the following department perform total cell count and differential count on the CSF specimen?

Hematology department

Which of the following risk groups has high community risk and preventive measures are not usually available?

Risk group 4

Which of the following BSC sterilizes the air in-and-out on the cabinet?

BSC 2

BSL in which of the BSC utilizes negative pressure?

BSC 4

Which of the following chemicals disinfects by denaturing proteins?

Alcohol

What physical method of sterilization does the hot-air oven belong to?

Dry Heat

Which of the following RG does low and moderate community risk and tx and preventive measures are available?

Risk group 2

Which of the following names of bacteria follows the correct binomial nomenclature?

Klebsiella pneumoniae

Which of the following statements is true about the virulence factor of a blood loving organism causing meningitis in unvaccinated children?

causing infection on mucosal surfaces of the respiratory tract via the action of immunoglobin protease enzyme

Which growth factor or factors required by Haemophilus organisms present in blood is or are demonstrated in the blood agar plate with colonies of coagulase positive beta hemolytic staphylococcus.

X and V factors

Which specie under haemophilus genus produces the characteristic medium to large smooth translucent colonies on chocolate agar and non-hemolytic on blood agar?

Haemophilus parainfluenzae

A test procedure is performed on a broth, a heme producing specie of Hemophilus is assumed to be suspended in the broth once submitted to UV light examination using mood slam, the suspended broth flurries or reddish orange color, which of the following analyte is detected by the above procedure for reference when determining the X and V factor requirement of the Haemophilus isolate using the impregnated discs the milky Halo is surrounding only at the thermo stable blood factor. Which of the agar plates is the appropriate culture medium to use for the isolation of this organism?

Blood agar

Which virulence factor of Bordetella Pertussis is responsible for ciliary dysfunction and tissue damage causing the characteristic whooping cough?

Tracheal cytotoxin

If delay is anticipated in the processing of a nasopharyngeal swab for Bordetella pertussis isolation, which of the following is the correct transport medium for the said sample?

Casamino acid broth

Which stage of Pertussis infection is considered highly contagious because the organism is present in large numbers in the respiratory tract?

Catarrhal stage

A test for immunity to corynebacterium diphtheriae?

Schick test

Establishing the pathogenicity of a microorganism isolated from a child's throat and identified as corynebacterium diphtheria would depend upon?

a positive Elek test

A throat swab was submitted for routine bacterial culture. DME reveals gram positive clubbed shaped bacilli after 24 hours of incubation at 37 degrees Celsius. There was no growth on macconkey agar. But there is distinct growth on sheep blood agar. Colonies appear as small gray granular with irregular edges and have a very small zones of beta hemolysis. Which biochemical test results differentiates this bacteria from streptococci?

positive catalase test

A urine sample was submitted to the lab for bacterial culture. DME reveals gram-positive pleomorphic bacilli with metachromatic granules. After 72 hours of incubation there was no growth on SBA, what could be the most likely reason for this?

Between 80 was not incorporated into the culture medium.

Sam Well, a 38 year old obese male presents with brown scaly lesion on the inguinal area. The lesions emit a coral red color under a wood slab, the most likely antibiotic ecologic agent would be that of?

Corynebacterium minutissimum

Jennifer, a 24-year-old female is diagnosed with UTI, colonies are pinpoint white colonies that have a characteristic diptheroid microscopic morphology. The most likely clinical isolate would?

demonstrate a magenta pink color on Christensen's urea broth within minutes off inoculation

The most common cause of diphtheroid prosthetic valve endocarditis in adults?

requires an incubation time of at least three days in artificial culture medium

Darren, who is the medical technologist assigned in microbiology department processed the nasal pharyngeal swabs submitted, identification and culture for nasopharyngeal swab reveals the following laboratory work of: gram positive club shaped rods stained with gram stain, pleomorphic non-spore forming bacilli, black or brown colonies with brown halo on ctpa presence of bubbles when added with hydrogen peroxide, pink color of Christensen urea agar. Which of the following is most likely the isolate?

Cornybacterium ulcerans and Cornybacterium pseudotuberculosis

Which of the following statements are true about the Elek test?

a positive toxin production is indicated by an arch of identity

A composition of tinsdale agar that inhibits the growth of non Coryneform bacteria?

Tellurite

The bacterium which is novobiacin resistant is?

Staphylococcus saprophyticus

What is responsible for the beta hemolysis of Staphylococcus aureus?

Cytotoxins

What virulence factor of the staphylococcus is a leukocyte chemoattractant?

Peptidogylcan

A young woman recently underwent rhinoplasty to correct a deviated septum and her nose was packed post operatively. She experiences a two to three-day period of low grade fever, muscle aches, chills, and Mali. This was followed by the development of a sunburn like rash that covered most of her body. The packing was removed and a nasal swab grew grampositive cocci that were catalase positive and produced colonies on mannitol salt agar that were surrounded by a yellow halo. The bacteria clumped when mixed with rabbit plasma. What is your diagnosis?

Toxic shock syndrome

Very dense streptococci can be differentiated from Streptococcus pneumoniae by?

Bile solubility

The optochin disk is used for the identification of?

Streptococcus pneumoniae

Which two diseases are usually preceded by infection with beta hemolytic streptococci?

glomerulonephritis and rheumatic fever

Gram positive cocci in chains are seen on Gram stain from a blood culture. The organism grows as a beta homiletic colony, further tests that could be performed include?

Bile esculin, PYR, bacitracin, and Hippurate

Which of the following is used to decontaminate sputum specimens in preparation for TB study?

Sodium hydroxide

A 32-year old female was subjected to immunofluorescence study to diagnose tuberculosis. What stain is used to demonstrate yellow-orange color of mycobacteria?

Auramine

AFB smear was done on a suspected tuberculosis case. What does a 3+ result mean?

There are 1-9 acid-fast bacilli per field seen

Which of the following standard procedures is used in demonstrating capsule?

Anthony’s method

Which of the following techniques is correct in making smears from specimens collected from cotton swabs?

Rolling the swabs all over the surface of the glass slide

What is the primary stain and counterstain used in the Schaeffer-Fulton stain for endospores?

Malachite green solution and safranin

Which of the following statements best describes the dilution method of antimicrobial susceptibility testing?

It indicates the amount of drug necessary to kill the tested microorgansim

Susceptibility testing is most applicable when an infectious process is likely to be fatal unless treated specifically, sulfonamides are generally known to?

inhibit synthesis of essential metabolites

Prokaryotes has cellular organelles. It is absent in eukaryotes

both sentences are false

Obligate aerobes can survive in the presence of 20% Oxygen. These types of microorganisms have catalase enzyme

Both statement are true

Which of the following is the correct order of bacterial replication?

unwinding of supercoiled DNA, unzipping of DNA, synthesis of new DNA strands, termination of replication

Daniel complained to the physician of burning sensation when urinating and frequent urination for the past few days. A urinalysis and urine culture were immediately requested in the laboratory. Urinalysis showed a cloudy urine a positive nitrate test. After 5 days, the result of the urine culture was released and indicated a growth of 10^3 CFU/mL. Which of the following statements best interprets the urine culture result?

probable contamination

Which of these statements are incorrect of suprapubic aspiration for urine culture?

non-invasive procedure

In BacT/ALERT positive blood cultures are usually detected within 12 to 36 hours of incubation. fastidious organisms belonging to the HACEK group are detected after 24 hours

first statement is true, second statement is false.

Which of the following biosafety cabinet sterilize the air in and out of the cabinet?

BSC 2

Biosafety level in which the BSC utilizes negative pressure?

BSC 4

Which of the following chemicals disinfect by denaturing proteins?

alcohol

Isolation and identification of Bordetella pertussis organism?

grows pearly luster like colonies on potato enfusion Algar

Dacron, polyester swabs are placed immediately in proper transport medium after it is collected. True or False

False

x and v growth requirements of Haemophilus organism. Vitamin factor is supplemented by lysed blood agar. True or False

True

specie causing genital ulcer disease requires protoporphyrin IX factor only. True or False

True

PRP capsule containing strain requires the heat level factor only? True or False

False

Not part of normal flora.

These are the choices.

A=haemophilus influenza

B= Haemophilus ducreyi

C= either A or B

D= neither A nor B

B

anti-phagocytic property

These are the choices.

A=haemophilus influenza

B= Haemophilus ducreyi

C= either A or B

D= neither A nor B

A

Pink eye

These are the choices.

A=haemophilus influenza

B= Haemophilus ducreyi

C= either A or B

D= neither A nor B

\

D