Unit 1 Flashcards
To survive, microbial inhabitants have learned to adapt by varying all of the following, except
Bacterial shape
Who has considered the father of protozoology and bacteriology?
Anton van Leeuwenhoek
Prokaryotic cells have which of the following structures in their cytoplasm?
Ribosomes
The form of DNA is commonly found in eukaryotic cells
Linear
The nuclear membrane in prokaryotes is
Missing
A microorganism that is a unicellular organism and lacks a nuclear membrane and true nucleus belongs to which classification?
Bactria
In the laboratory, the clinical microbiologist is responsible for all the following, except
Selecting treatment for patients
What enables the microbiologist to select the correct media for primary culture and optimize the chance of isolating a pathogenic organism?
Understanding the growth requirements of potential pathogens at specific body site
A clinical laboratory scientist is working on the bench, reading plates, and notices that a culture has both a unicellular form and a filamentous form. What type of organism exhibits these forms?
Fungi
All of the following statements are true viruses, except
Viruses do not need host cells to survive and grow
Diagnostic microbiologists apply placement and naming bacterial organisms into all the following categories, except
Order
Bacterial species that exhibit phenotypic differences are considered
Subspecies
What structure is described as a phospholipid bilayer embedded with proteins and sterols that regulates the type and amount of chemicals that pass in and out of a cell?
Plasma membrane
What makes the interior of the plasma membrane potentially impermeable to water-soluble molecules?
The hydrophobic tails of the phospholipids molecules are found there
The function of a cell wall is to
Provide rigidity and strength to the exterior of the cell
Name the numerous short (3-10 um) projections that extend from the cell surface and are used for cellular locomotion
Cilia
A microbiology technologist performs a traditional bacterial stain on a colony from a wound culture that is suspected to contain bacteria from the genus clostridium. The unstained areas in the bacterial cell observed by the technologist are called
Endospores
This constituent of gram-positive cell walls absorbs crystal violet but is to dissolved by alcohol, thus giving the gram-positive cell its characteristic purple color
Peptidoglycan
Mycobacteria have a gram-positive cell wall structure with a waxy layer containing these two compounds
Glycolipids and mycolic acid
When performing a Gram stain on a gram-negative organism, the crystal violet is absorbed into this outer cell wall layer, and then washed away with the acetone alcohol. What is the main component of the outer layer of the cell wall?
Lipopolyaccharide
The three region of the lipopolysaccharide include all of the following except,
Myocolic acid
The outer cell wall of the gram-negative bacteria serves three important functions, which includes all the following except
It provides an attachment site for flagella, which will act in locomotion
Mycoplasma and Ureaplasma spp. must have media supplemented with serum or sugar as nutrients and because
The lack cell walls
Whaat is the purpose of a capsule?
Act as a virulence factor in helping the pathogen evade phagocytosis
The three basic shapes of bacteria include all the following except
Cell wall deficient
The gram stain is a routine stain used in bacteriology to determine gram-positive and gran-negative based on the
Composition of the bacterial cell wall
In what staining procedures does carbofuchsin penetrate the bacterial cell wall through heat or detergent treatment?
Acid-fast stain
What stain is used for medically important fungi?
Lactophenol cotton blue
All of the following are types of media, excerpt
Fastidious
Which of the following environmental factors influence the growth of bacteria in the laboratory?
All of the above
* pH
* temperature
* Gaseous composition of the atmosphere
Some bacteria grow at 25-42 C, but diagnostic laboratories routinely grow pathogenic bacteria at what temperature?
35C
Which of these bacteria cannot grow in the presence of oxygen?
Obligate anaerobe
What class of organisms, such as the Streptococcus sp., can survive in the presence of oxygen but do not use oxygen in its metabolic processes?
Aerotolerant anaerobe
The laboratory receives a specimen in which the doctor suspects that the infecting organism is carbon dioxide. It is therefore classified as what type of bacteria?
Capnophilic
The following describes the log phase of bacterial growth
Bacteria doubling with each generation time
Diagnostic schemes is the microbiology laboratory typically analyze each unknown bacterium’s metabolic processes for all the following, except
Energy utilization for metabolic processes
Which is a biochemical process carries out by both obligate and facultative anaerobes?
Fermentation
What type of fermentation produces lactic, acetic, succinic, and formic acids as the end products?
Mixed acid
If bacteria utilize various carbohydrates for growth, they are usually detected by
Acid production and change of color from the pH indicator
In the medical microbiology laboratory, the ability of gram-negative bacterium to ferment this sugar is the first step in its ID
Lactose
A ________ is a single, closed, circular piece of DNA that is supercoilded to fit inside a bacterial cell
Chromosome
Genes that code for antibiotic resistance are often found on small, circular pieces of DNA. The DNA pieces are called
Plasmids
What process involves transferring or exchanging genes between similar regions on two separate DNA molecules?
Recombination
A microbiologist is working with two separate cultures of the same organism. The bacteria in one culture are resistant to penicillin, whereas the bacteria in the other culture are susceptible to penicillin. The bacteria from both cultures are mixed together, and all the resulting bacteria are resistant to penicillin. What caused this phenomenon?
The plasmid carrying the resistance gene was transferred to the susceptible population of bacteria
Diphtheria is a disease produced by corynebacterium diphtheria. However, not all C. Diphtheriae bacteria produce the toxin that causes this disease. To produce the toxin, the bacteria must first become infected with a bacteriophage. The process by which bacterial genes are transferred to new bacteria by the bacteriophage is called
Transduction
Lysogeny occur when
Genes present in the bacteriophage DNA are incorporated into the bacteria’s genome
These are enzymes that cut the bacterial DNA at specific locations
Restriction enzymes
Organisms that participate in a biological relationship where both benefit from one another are called
Symbionts
Parasitism is
A biological relationship in which one species gains benefits at the expense of the host
This bacterial state occurs when a host harbors a disease-causing organism, but does not show signs of disease
Carrier
Healthy people are colonized by many different sites. These bacteria are referred to as
Indigenous flora
Diabetics may sometimes be infected with their own resident flora. This type of infection is called
An opportunistic infection
Mechanism used b the skin to prevent infection and protect the underlying tissue from invasion by potential pathogens include all the following, except
Antibiotics that inhibit many microorganisms
A laboratory professional is testing a new antimicrobial soap. The tech washes her forearm then does a culture of the skin. Which organisms should she most likely expect to find growing in the culture?
Staphylococcus epidermis and propionbacterium
What mechanism allows strict anaerobes to grow in the cervices and areas between the teeth when plaque is present?
A low oxidation-reduction potential occurs at the tooth surface under the plaque
The stomach can be considered a first line of defense against microbial infections because
Most microorganisms are susceptible to to the acid pH of the stomach
This type of bacteria is able to live in the colon with little to no oxygen and is the predominant organisms
Anaerobes
After perforation of the colon, surgeons must guard against infection in the _________ because of leakage of the contents of the colon
Peritoneal cavity
The human body is constantly challenged by pathogens in the environment. It is not infected by every pathogen it encounters because the microbial flora
Produce conditions at the microenvironmental level that block colonization
The ability of an organism to produce disease in an individual is called
Pathogenicity
A patient with a n indwelling catheter develops a fever and lethargy. In addition, the urine in the catheter bag has turned a brownish color and smells foul, which suggests an infection is present. What type of infection does this describe?
Iatrogenic
The smaller the number of microorganism necessary to cause infection in competent Host, the more _______ ad the microorganism
Virulent
Factors the determine the pathogenicity and increase the virulence of organism include all the following, except
An organisms ability to produce infection when host conditions change
The most common bacterial characteristic that allows for evasion of phagocytosis by the host is called
Polysaccharide capsule
This is a leukocidin that is lethal to leukocytes and produces by staphylococci
Panton-valentine
Changes in these host structures can result in lower virulence of microorganism
Adhesion receptors
After attachment to host cells, a pathogen may use the following mechanisms to establish itself and cause disease, except
Produces lysozyme to kill the host cell
Dissemination of a pathogen is
When infection with a pathogen spreads from the initial infection site to distant site such as organs and tissues
A physician notices that several patients are infected with clostridium difficile, but only a few of the patients are symptomatic for disease. The reason for this discrepancy is
Only those strains of the organsisms carrying the extrachromosomal DNA coding for the toxin gene will produce ten and cause the individuals to be symptomatic
The effects of endotoxins consist of dramatic changes in all the following, except
Fluid imbalance
A patient is brought to the emergency room with the following symptom: body temperature of 102 F, low blood pressure, elevated WBC, and disseminated intravascular coagulation. This person has gram-negative rods growing in the blood. What is responsible for these symptoms?
Endotoxin
Healthy skin secretes these substances to help prevent colonization by transient and possibly pathogenic organisms
Long-chain fatty acids
Lysozyme is
A low-molecular-weight enzyme that hydrolyzes the Peptidoglycan layer of bacterial wall
Interferon is a substance produced by the body that inhibits viral replication. Interferon accomplishes this task by
Binding to surface receptors that stimulate the cell to synthesize enzymes that inhibit viral replication over several days
All of the following activities must occur for phagocytosis to take place and be effective in host defense, except
Migration of lymphocytes to the area of infection (chemotaxis)
This process results in enhanced phagocytosis by neutrophils
Opsonization
One of the most effective defenses bacteria have against phagocytosis is
The capsule
Innate immunity consists of which of the following components?
All of the above are part of the innate immune system
The major constituents of the adapative of specific immune response are
Lymphocytes
The class of antibodies is usually found as a pentameter
IgM
A subsequent exposure to the same antigen elicits a(n) ________, characterized by a rapid increase in IgG antibody associated with higher levels, a prolonged elevation, and a more gradual decline in antibody levels
Anmnestic immune response
These are low-molecular-weight proteins secreted by T cells
Lymphokines
Immunity to intracellular bacterial pathogens, such as mycotoxins bacterium tuberculosis, is primarily cell mediated, through the activities of
T lymphocytes, lymphokines, and a macrophages
Pathogens can be transmitted through all the following routes, except
Handwashing
Because infections can be encountered via the air, _______can cause transmission of some pathogens
Coughing
The resulting disease from this route of transmission is a disease of animals that is transmitted to humans
Zoonotic
The chemical or physical method that destroy all forms of life is called
Sterilization
Organisms that are the most resistant to heat, chemicals, and radiation are
Prions
After using the phone, the laboratory tech sprayed the receiver with a chemical spray. This process will kill a defined scope of microorganisms. What is this process called?
Disinfection
before performing a phlebotomy, the phlebotomist will clean the area on a patients arm with a substance before inserting needle. This substance is called an
Antiseptic
All of the following factors play a significant role in the selection and implementation of the appropriate method of disinfection, except
Humidity
When eliminating organisms from inanimate objects, higher numbers of organisms require longer exposure time because
It takes longer to eliminate 99% of microorganisms
If this is present on a surface to be disinfected, it can shield microorganisms from the disinfectant or inactivate the disinfectant. What is this substance?
Organic material
Disinfectants are usually used at this temperature
20-22 C
Pasteurization achieves______?
Disinfection
Chemosterilizers exert their killing effect through all the following mechanisms, except
Inactivating enzyme substrates
Alcohol use this mechanism to inactivate microorganisms
Denature proteins
The tech needs to sterilize a piece of equipment that cannot be autoclaved or gas sterilized because the equipment contains lenses, metal, and rubber components. What solution should be used to sterilize this piece of equipment?
Glutaraldehyde
For the most effective microbial killing, all iodophors must be properly diluted because
There must be enough free iodine to kill the microorganisms
Even though hypochlorites are inexpensive and have broad range of microbes that they kill, they are not used as sterilants because of
Long exposure time for sporicidal action
Many materials in hospitals that must be sterilized cannot withstand steam sterilization. Gas sterilization is used instead, using this gas
Ethylene oxide
Why should health care workers wash their hands after coming into contact with a patient?
To reduce the spread of pathogenic bacteria from one individual to another
High-level disinfectants are active against all the following, except
Parasites
This agency regulates the use, sale, and distribution of antimicrobial pesticide products from certian inanimate, hard, nonporous surfaces, or incorporates into substances under the pesticide law
Antimicrobial division of environmental protection agency (EPA)
These two alcohols are effective in killing enveloped viruses such as Hepatitis B virus (HBV)
70% isopropyl and 95% ethanol
This chemical is a saturated 5-carbon dialdehyde that has broad-spectrum activity, rapid killing action, and remains active in the presence of organic matter
Glutaraldehyde
These disinfectants are cationic, surface-activated agents that work by reducing the surface tension of molecules in a liquid, resulting in the disruption of the cellular membrane of microbes
Quaternary ammonium compounds
This organization regulates chemical skin antiseptics
FDA
The main goal of handwashing is to
Eliminate transient floras
Routine handwashing in health care settings mandates washing as all the following times, except
When gloves become soiled during a procedure or dressing change on the same patient
The purpose of surgical hand scrubs and waterless hand rubs is to
Eliminate the transient flora and most of the resident flora on the skin
The most common iodophor used in the US for pre operative skin preparation is
Povidone-iodine
This topical antiseptic disrupts the microbial cell membrane and precipitates the cellular contents
Chlorhexidine gluconate
This compound is a diphenhydramine ether and it exerts its bactericidal effects by disrupting the cell wall. It has good activity against gram-positive cocci, but poor activity against fungi. What is its name?
Triclosan
Laboratory safety includes all the following areas, except
Isolation
Why is laboratory-acquired infection an obvious hazard for personnel working in a microbiology laboratory?
Personnel deal with a variety of infectious agents: viral, fungal, parasitic, and bacterial
The comprehensive safety program from the microbiology laboratory needs to fulfill all the following provision, except
It is specific to the hospital and does not need to conform to state, local, and federal regulations
Processing of patient specimens and handling of actively growing cultures of microorganisms put an employee at risk of potential contact with the infection agent through all the following routes, except
Blood splashed onto intact skin
All of the following organisms can typically cause infection from aerosolization of specimens, except
Staphylococcus aureus
What protective measures can a laboratory worker take when working with actively growing cultures to ensure that they do not become infected?
Ensure that fungal cultures are sealed and worked in bio safety cabinet
The laboratory exposure control plan should contain all the following, except
Review of control plan every 5 years
Universal/standard precautions require that
Blood and body fluids from all patient be considered infectious and capable of transmitting disease
Engineering controls and work practice controls to ensure standard precautions are followed include all the following except
Fire blankets
Standard precautions do not address which of the following
Respirators
Safety program and work practice controls consist of all of the following except
Allowing workers to eat at the bench if it gets busy and they do not have time to take a lunch break
All of following are examples of PPE, except
Prescription glasses
Technicians are doing the morning chemistry run. Once they load the specimens onto the instrument, they remove their gloves to do paperwork in a clean area of the laboratory. What should the technicians do after removing their gloves?
Wash their hands
The biosafety levels were categorized using all the following criteria, except
The bacterial load necessary to cause infection
A biosafety level 1(BSL-1) level of containment is used for organisms that
Are well classified and not known to cause disease in healthy people
A biosafety level 2 (BSL-2) level of containment is used for organisms that
Create a moderate potential hazard for employees and the environment
Because biosafety level 3 (BSL-3) organisms have the potential for aerosol transmission, and disease with these agents may have serious lethal consequences, all of the following guidelines apply to BSL-3 laboratories, except
BSL-3 laboratories should have positive air pressure
Biosafety level 4 (BSL-4) organisms are dangerous, exotic and pose an increased risk of aerosol-transmitted infections and life-threatening disease. Two examples of BSL-4 organisms are
Marburg and Congo-Crimean hemorrhagic fever
OSHA requires laboratories to have this document to ensure that laboratory personnel have a thorough working knowledge of the hazards of the chemicals with which they work
Chemical hygiene plan
A material safety data sheet (MSDS) contains all the following information, except
Classification of a chemical (acid, base, protein)
If a laboratory uses hazardous chemicals, it must
Keep a chemical inventory and MSDSs on hand
Laboratory safety for hazardous chemicals includes
Using fume hoods to prevent inhalation of fumes
Most institutions use the RACE acronym to respond to a fire emergency. RACE stands for
Rescue, alarm, contain, extinguish
The best way to care for your back is to prevent back injuries. All of the following are some ways to prevent back injuries, except
Carefully lifting heavy objects overhead
Three levels of laboratories outlined in the laboratory response network (LRN) include all the following, except
First responder
In the LRN programs, hospital based microbiology laboratories are classified as this type of laboratory
Sentinel
Category A bioterrorism agents
Pose the highest threat because they are easily transmitted and highly infectious
Once bioterrosim is suspected, a sentinel laboratory should perform all culture manipulation using these safety guidelines
BSL-3
Quality control is designed to
Ensure the medical reliability of laboratory data
Actual laboratory testing is called an
Analytic activity
All of the following activities will directly affect the quality of laboratory test, except
Accreditation
In January 2004, The Joint commission (TJC) implemented performance measurements for organizational systems that are critical to patient safety, quality of care, treatment, and services. This new initiative is called
Shared visions new pathway
All of the following activities are included in a laboratory quantity control program except
Air quality
The morning technician arrives at the microbiology laboratory and goes around checking daily temperatures. This person will check temperatures daily on all of the following equipment, except
Centrifuges
Thermometers used in the laboratory must be calibrated before the are put into use. This is accomplished by
Checking against an NIST thermometer
Preventive maintenance on an instrument includes all the following except
Disinfecting the surface of the instrument
Commercial media must have quality control testing performed by the manufacturers. Because of high failure rates, all of the following media must be retested by the hospital laboratory, except
Trypticase soy agar with 5% sheep blood
Media that do not need to be retested by the hospital laboratory must still undergo observation for all of the following except
Organism colony characteristics
When a medium needs to be quality controlled because it was prepared in house or because it is complex, all the following rules must be followed except
Only media not specified in clinical and laboratory standards institute (CLSI) guidelines should be tested
Reagents that should undergo quality control in the microbiology laboratory include all the following except
Immersion oil
In any susceptibility system, variables that can affect the results the following:
*antibiotic potency
*incoculum concentration
*pH
Susceptibility testing of control organisms is usually conducted daily until precision can be demonstrated with ______ or _______ days of susceptibility testing using CLS guidelines
20; 30; consecutive
How can personnel competency be determined?
Proficiency testing
The following are provisions of CLIA 88 except
Revering the employees competency monthly
Quality control stock cultures are available from all of the following, except
CDC
Popular media choices for maintaining stock cultures include
Tryptic soy agar deeps
Which of the following is an example of a mission statement for an institution?
“Working together for a healthy America”
All of the following are components of TJC recommendations for establishing performance monitors, except
Do
Customers of a laboratory include all of the following except
Accrediting organizations
Multiple unlabeled specimen have been sent to the laboratory from multiple in-patient locations. The laboratory mangager decides corrective action needs to occur. What should be constructed to evaluate and correct the problem?
Make a cross-functional team
When a broken process fixed?
When the problem is prevented from happening again
What is benchmarking?
Seeking an industry’s or profession’s best practices to imitate and improve
When performing tests in the microbiology laboratory, the detection limit of a test refers to the ______ of that test
Analytic sensitivity
A technician is performing a chemistry test on a control sample. The technician gets the following values for the control: 4.3, 4.3, 4.3, 4.2, 4.4, 4.3, 4.2 and 4.4. The actual value is 4.3. These results are said to be
Accurate
A test is performed on a group of 10 patients. Six patients have a disease, and four are free or the disease. If six, patients (all known to have to the disease) of this group test positive for the disease, we say that the clinical sensitivity of this test is
100%
A group of 10 patients are to be tested: six are known to have a disease and four are disease free. if the four disease-free patients tested negative for this disease, what would the clinical specificity of this test be?
100%
Incidence is
The number of new cases of disease over a period of time
A test can have a positive and a negative predicative value (NPV). All of the following elements are needed to compute the positive and NPV of a test, except
Type of disease being tested
Assume that a certian test for group A streptococcus has reported sensitivity and specificity of 90-98%, respectively, and the estimated prevalence for group A streptococcus infection in acute pharyngitis is 5%. What is the PPV of this test?
70.3%
Usually, negative test results are more reliable in predicting
The absence of disease
The efficiency of a test indicates
The % of patients who are correctly identified as having or not having the disease
Screening is
Used for testing large population of patients
Confirmation is used after
Obtaining a positive screening result
When choosing a test to perform in your laboratory, an in-house verification is always performed. Verification of a test
Serves to establish that the performance parameters of the test are satisfactory
Test validation is the ongoing process of providing information that a test is performing correctly. The components of validation include all the following, except
Specimen requirements
All of the following provide guidelines to ensure the continual correct performance of tests, except
CDC
Data generated by the laboratory is directly influenced by
The quality of the specimen and its condition when received
To assist hospital personnel in collecting the highest quality specimen, the laboratory should q
Develop a well-written handbook and make it available at every patient care unit
The goal of the specimen collector when collecting specimens for culture should be to
Maintain the viability of the living organism at the site with minimal contamination
All of the following principles of specimen collection are fundamental to ensuring appropriate specimen management, except
It is acceptable to delay transport of the specimen to the laboratory if it is in transport media
Why is it acceptable for a fecal sample to be collected in a nonsterile container?
Manu types of bacteria call the intestinal tract home; the specimen cannot become contaminated
Swabs are appropriate for specimens collected from all the following sites, except
Urine
How should specimen collection instruction be given to the patient to ensure collection of a good specimen for culture?
Both verbal and written instruction in simple language
Why is clean-catch midstream urine used for a urine culture as opposed a clean catch urine?
The first portion of the urine flow washes contaminants from the urethra and the next portion of urine is more representative of the bladder
Sputum specimens are often collected for the diagnosis of q
Bacterial pneumonia
The best way to minimize the amount of upper respiratory flora in a sputum specimen is to follow which of these procedures??
Have the patient rinse the mouth with water and expectorate with the aid of a really deep cough directly into a sterile container
The specimen of choice for detecting GI pathogens is
A stool specimen
Proper ID of each specimen includes a label firmly attached to the container with all the following information except
Diagnosis
To perform a quality laboratory analysis, the laboratory needs specific information regarding the patient and the specimen. What can be critical weak link in the specimen management process?
Incomplete information on the requisition
The requisition form should provide all the following information, except
Patient home address
If a test is not considered appropriate for the specimen, the following should happen
The laboratory needs to communicate with the physician to determine exactly what needs to be done
All specimens must be transported
In leakproof secondary containers
A safe method of transporting aspirated wound material would be in
An anaerobic transport system
What is the primary goal in the transportation of specimens to the laboratory?
The maintain the specimen as near its original state as possible with minimal deterioration
If transport of the specimen is delayed, the specimen can be maintained by all of the following, except
Saltwater
A night technician is working in microbiology when a CSF specimen comes in. Almost simultaneously, the technician is called to the emergency department to draw blood on seriously injured car crash victims. How would the technician store the CSF until time permits to work on the CSF specimen?
Place the specimen in a 35C incubator whee it is good for up to 6 hours
Two types of specimens can use preservatives to maintain them until they can be delivered to the laboratory. They are
Urine, stool
Specimens such as blood, bone marrow, and synovium are mixed with anticoagulants right after collection. Why should this occur?q
Organisms become bound up in the clotted material and are difficult to isolate
The purpose of transport media is to
Ensure the preservation of microorganisms in the specimen
In certain instances, it is desirable for specimens to be inoculated directly onto culture media. Specimens for this pathogen can be placed onto a commercial transport system called a James E. Martin Biological Environment Chamber (JEMBEC) system. What pathogen is this?
Neisseria gonorrhoeae
The shipment of clinical specimens and cultures of microorganisms is governed by a complex set of national and international guidelines issued by
The Department of Transportation (DOT) and the U.S. Postal Service
How does the DOT define an infectious substance ?
A metrical known to contain or is suspected of containing a pathogen that causes disease in humans or animals
A technician receives a package from a supplier of quality control microorganisms. The package has a small watertight vial in a larger watertight tube. The larger tube has some bubble wrap around it, but the larger tube is just placed in the fiberboard box. All of the following was right with this packaging, except
The primary receptacle was placed into the secondary container with no absorbent material
All of the four levels represents a possible scheme for prioritizing the handling of specimens, except
Level 4: anticoagulated
Types of specimens that can be batch processed, including all the following except
Specimens for fastidious organisms
All of the following are examples of suboptimal specimens that must be rejected, except
The specimen is for a Neisseria gonorrhoeae (GC) culture and submitted in a JEMBEC system
The technician in the laboratory has received a specimen that is rejected. The technician calls the physician and tells the physician the specimen is unacceptable and the reason why. The physician insists that the culture needs to be performed on this unacceptable culture. What should the technician do?
Plate the culture, but include a comment explaining the potentially compromised test results
Notations from the macroscopic (gross) examination of a specimen should include all the following except
What type of container the specimen was collected in
The direct microscopic examination is a useful tool for all the following reasons, except
It can tell the physician what type of normal Flora is present on the smear and if it is anaerobic or aerobic
Direct microscopic examinations are not recommended for all the following specimen sources except
Urethral discharge from a male
Nonselective media supports
The growth of most non-fastidious microbes
selective media
Support the growth of one type or group of microbes, but not another
Differential media
Support the grouping of microbes based on different characteristics demonstrated in the media
Enriched media
Allow the growth of fastidious microbes through the addition of certain growth enhancers
An enrichment broth is
A liquid medium designed too encourage the growth of small numbers of a particular organism while suppressing other flora
How is culture media selected for specimen plating?
The selection of media to inoculate is based on the type of specimen submitted for culture and the organisms likely to be involved in the infectious process
Routine primary plating media include all of the following items, except
Special biochemical media
What method is used to concentrate specimens to increase recovery of pathogens in the microbiology laboratory?
Centrifugation
What technique is used to isolate bacterial colonies when inoculating organisms onto an agar plate?
Isolation streaking
When using the isolation streaking technique, the greatest concentration of organisms (if present) will be in which quadrant??
First
When using the isolation streaking technique, the most isolated forms of the organism should be in which quadrant?
Fourth
If a 0.001 mL quantitative loop is used to inoculate plate media for a urine culture, each colony of growth represents how many organisms per mLs in the original sample?
1000 organisms
Most bacterial cultures are incubated at this temperature range
35-37C
Aerobes are bacteria that grow
In ambient air
Microaeorphiles are bacteria that grow
In reduced oxygen concentration but increased carbon dioxide concentrations
Capnophiles are bacteria that grow
An increased carbon dioxide concentrations
Anaerobes are bacteria that grow
Where little or no oxygen is present
Cultures for anaerobes and broth cultures may be incubated for
5-7 days
All of the following are questions that microbiology technologist will ask while reading and interpreting the growth of cultures, except
How long has this culture been incubated?
What woke practice have microbiologists incorporated to keep laboratory testing cost-effective while providing optimum patient care?
Limited ID procedures
When plating a nonroutine culture on primary culture media, the technician should ask all the following questions, except
What anaerobic bacteria will be present in this specimen?
Nonroutine specimens can include all the following specimen types, except
Syringe needles
To help the microbiologist report microbiology results to the physician in a timely fashion to ensure the appropriate treatment, the technician may use this report
Preliminary
Culture results
Confirm the correctness of the therapeutic choices already made and implemented
All of the following steps should be used to prepare a smear from thick, granular, or mucoid materials, except
Take an additional swab and rub it back and forth on the two glass slides to ensure the material is thin enough to read once it is stained
When making slides of this materials such as urine and CSF
Mark the area of the sample drop on the reverse side with a wax pencil and then place drop of the specimen into the marked area
A cytocentrifuge is an excellent method of preparing non viscous fluids, because
It deposits cellular elements and microorganisms from the specimen onto the surface of a glass slide a monolayer
The purpose of a simple stain is to
Color the forms and shapes present
In the microbiology laboratory, this instrument is routinely used to examine smears for structures that are too small to be seen with the unaided eye
Compound microscope
Polymicrobial presentations in smears require more interpretation and must take into account all the following except
Method used to make the smear
Commonly encountered polymicrobial infections are common in
Perirectal abscesses
When a laboratory proffessional examines a specimen smear, he or she should be looking for all the following except
Mucus
Why should laboratory professionals look for contamination of a specimen by normal microbial flora?
Contamination of specimens with normal flora that are not collected from sterile sites diminishes the value of the culture studies
When examining specimen smears for pathogenic bacteria, this is important to note
Intracellular and extracellular forms
Because cell wall-damaged bacteria, antibiotic-treated bacteria, or dead bacteria may appear falsely gram-negative, the following are considered “critical cocharactristics” that assist in the interpretation of the smear include
Shape size
If a symptomatic patient presents to a physician with and infection, the physician will treat the patient with antibiotics. What role does the laboratory play in antibiotic selection if the physician has already treated the patient before receiving the culture results?
The physician expects the laboratory to affirm or reject the antibiotic choice made after the presumptive diagnosis
All of the following are signs of acute inflammation on a bacterial smear, except
Mucus
All of the following cell reflect chronic inflammation except
Neutrophils
A bacterial smear may indicate a polymicrobial infection when
More than one morphologic type of bacteria is present on the smear
The direct microscopic examination of infected materials, along with specimen site historical information, may suggest modifications in routine culture techniques to allow the isolation of a suspected pathogen. Common modifications include all of the following except
Changing the amount of humidity in the incubator
Bartletts method for scoring sputum and the Murray-Washington method for contamination assessment associate what with unacceptable sputum specimens?
10-20 Squamous epithelial cells/ 10x field
Contaminating materials include all of the following except
Crystallized Gram stain
the most bothersome contaminating materials for the laboratory professional are those that
Contain microorganisms that will grow in culture and confuse the culture evaluation
Local material that may be added in the criteria for accepting or rejecting a respiratory specimen include all the following except
Bacterial ropes
To assist the physician and the laboratory professional in interpreting sputum smears, all of the following local materials are quantitated except
Mucus
What elements should be included in the direct examination of a microbial smear?
Only these elements useful in characterizing the specimen
You are working in a microbiology laboratory and receive a sputum culture. You perform a Gram stain on the sputum, and get the following results: 3+ gram-positive cocci, greater than 25 epithelial cells/ 10x field, less than 10 neutrophils/10x field, and heavy mucus. What do these results indicate
An unacceptable specimen and work up that should be limited to basic ID of bacteria
