Microbial Identification Techniques

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Which of the following methods is used to obtain pure cultures for accurate identification of microbes?

High-temperature incubation
Isolation media cultivation (correct)
Molecular sequencing
Antibiotic treatment

Biochemical tests utilize physical reactions to determine the presence of enzyme systems in bacteria.

False (B)

Name one predominant biochemical test used in identifying bacteria.

Carbohydrate fermentation

What is the advantage of using genotype over phenotype in microbial identification?

It allows for identification without culturing microorganisms. (B) Signup and view all the answers

Differential media is used to cultivate microorganisms without identifying specific characteristics.

False (B) Signup and view all the answers

Knowing an enzyme present in a specimen can often identify the ______ species.

bacterial Signup and view all the answers

Match each biochemical test with its function:

Carbohydrate fermentation = Production of acid and/or gas Gelatin hydrolysis = Breakdown of gelatin Catalase test = Detects enzyme that breaks down hydrogen peroxide Coagulase test = Identifies ability to form clot with plasma Signup and view all the answers

List one method used for the direct identification of diseases.

Direct tests, symptoms, or cultivation. Signup and view all the answers

A patient's blood is cultured in a special bottle of broth to identify pathogens, commonly referred to as _____.

blood cultures Signup and view all the answers

Match the following conditions or methods with their identification approach:

AIDS = Serological tests and symptoms Athlete's foot = Symptoms only Differential media = Identifying characteristics Cultivation = Growing and isolating organisms Signup and view all the answers

What is the purpose of the Western blot test?

To confirm an HIV infection (B) Signup and view all the answers

The Western blot test can be used as a standalone test for HIV diagnosis.

False (B) Signup and view all the answers

What are the three types of lines that can form in a double diffusion test?

line of identity, line of non-identity, line of partial identity Signup and view all the answers

In an agglutination reaction, antigens are __________ such as RBCs or bacteria.

whole cells Signup and view all the answers

Match the following terms with their definitions:

Western Blot = Test to confirm HIV infection Agglutination = Involves whole cells as antigens Precipitation = Involves soluble molecules as antigens Double Diffusion = Technique using agar gel to evaluate antibody-antigen interaction Signup and view all the answers

What is the primary purpose of phage typing?

To identify Salmonella (D) Signup and view all the answers

Carbohydrate fermentation tests are conducted to identify bacterial susceptibility to antibiotics.

False (B) Signup and view all the answers

What are the cleared areas on a Petri dish during phage typing indicative of?

Sensitivity to that phage Signup and view all the answers

The ________ involves mapping off a Petri dish into blocks for testing bacterial susceptibility to viruses.

phage typing Signup and view all the answers

Which of the following is not a component of the carbohydrate fermentation test?

Bacterial toxicity testing (C) Signup and view all the answers

What is the main purpose of Polymerase Chain Reaction (PCR)?

To amplify minute quantities of nucleic acids (A) Signup and view all the answers

Random Amplified Polymorphic DNA (RAPD) uses specific sequences of primers to identify known microbial populations.

False (B) Signup and view all the answers

What is the role of probes in hybridization techniques?

To bind to specific nucleic acid sequences from a microbe for identification. Signup and view all the answers

In Fluorescent in situ Hybridization (FISH), probes are used to locate ______ cells in patient specimens.

glowing Signup and view all the answers

Match the following genotypic techniques with their main applications:

PCR = Amplifying DNA or RNA RAPD = Identifying unknown microbial populations Hybridization = Identifying microbes through genetic material FISH = Locating specific microbes in samples Signup and view all the answers

Which genotypic technique is specifically used to confirm diagnoses or identify biofilm components?

Fluorescent in situ Hybridization (C) Signup and view all the answers

Pulse-Field Gel Electrophoresis is a method used to amplify DNA in diagnostic tests.

False (B) Signup and view all the answers

Hybridization involves the use of ______ that are complementary to specific nucleic acid sequences from a microbe.

probes Signup and view all the answers

What does the sensitivity of an immune test reflect?

The degree to which a test detects every positive person (B) Signup and view all the answers

Agglutination reactions involve soluble antigens.

False (B) Signup and view all the answers

What are the visual indicators used to observe antigen-antibody interactions?

Dyes or fluorescent reagents Signup and view all the answers

In the RPR test, antibodies cause the ________ particles to agglutinate.

lipid Signup and view all the answers

Match the terms with their definitions:

Agglutination = Involves whole cells or organisms Precipitation = Involves soluble antigens Sensitivity = Ability to detect minute quantities of antibodies RPR Test = Uses lipid particles for agglutination Signup and view all the answers

Which characteristic distinguishes precipitation from agglutination?

Location of the antigen (A), Size of the antigen (D) Signup and view all the answers

What is the primary component of the 30s subunit of bacterial and archaeal ribosomes?

16s ribosomal RNA (C) Signup and view all the answers

Smaller antigen-antibody complexes can typically be observed with the naked eye.

False (B) Signup and view all the answers

What occurs when RPR antigen is mixed with plasma and antibodies are present?

Agglutination occurs. Signup and view all the answers

Ribotyping is primarily used for identifying viruses.

False (B) Signup and view all the answers

Whole human or microbial cells form clumps with antibodies of the correct ________.

specificity Signup and view all the answers

What is the main purpose of serological testing?

To detect, identify, and quantify antibodies or antigens. Signup and view all the answers

In ribotyping, rRNA is ____ and analyzed from cultured cells.

isolated Signup and view all the answers

What type of antigen is involved in precipitation reactions?

Soluble molecules (D) Signup and view all the answers

Match the following substances with the types of materials that can be tested using modern serological methods:

Urine = Body fluid Cerebrospinal fluid = Body fluid Whole tissues = Tissue sample Saliva = Body fluid Signup and view all the answers

Which of the following statements about antibodies is true?

Antibodies have extreme specificity for antigens. (C) Signup and view all the answers

Immunologic methods can only detect unknown antigens using known antibodies.

False (B) Signup and view all the answers

What characteristic of a test ensures it only reacts with a specific antibody or antigen?

Specificity Signup and view all the answers

Ribotyping is suited for bacterial identification and diagnosis of ____.

infection Signup and view all the answers

Which of the following can be tested using modern serological methods?

Urine (A), Blood (D) Signup and view all the answers

Genus and species identification

The process of determining the specific type of microorganism or organism, using physical characteristics, biochemical reactions, immunological tests, and genetics.

Phenotypic identification

Identifying organisms by their observable physical characteristics and functions, including their shape, behavior, and biochemical activities (enzymes).

Specimen collection

Gathering a sample from a patient to find the microorganism causing an illness.

Microbial Identification Steps

Identifying a microbe by examining patient symptoms, collecting specimens, and then either directly testing them or cultivating them to isolate and identify the pathogen.