IDENTIFICATION METHODS- SEQUENCING, MULTIPLEX, MALDI,COMMERCILA KITS

When identifying Mycobacteria by molecular methods, the most reliable gene sequence is:

16S

Sequence-based analysis is an alternate method used to identify bacteria and fungal isolates. This methodology uses rRNA genes (rDNA) and their intergenic regions as common target sites to identify these organisms. Which of the following rRNA gene target sites is used to identify bacterial isolates?

16S rRNA

Polymerase chain reaction (PCR) copies DNA through repeated cycles of three basic steps. What is the correct order of these steps?

Denaturation, annealing, extension

Which of the following serological tests would be used for the diagnosis of Q-fever?

EIA or indirect immunoflourescence

All of the following would be suitable for identification of bacterial antigens, EXCEPT?

Gram Stain Reactions

Rocky Mountain spotted fever (RMSF), caused by Rickettsia rickettsii, is MOST reliably diagnosed by which laboratory technique?

IFA testing

The reactions in a portion of the API strip, shown in the photograph, most closely identifies which organism?

Klebsiella pneumoniae

Using molecular methods to identify organisms can provide GREATER specificity when compared to phenotypic methods. Which of the following organisms would molecular methods not be beneficial over phenotypic methods in identification?

Klebsiella species

Matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) is used for identification of aerobic bacterial isolates on a urine culture bench. Upon placing the target into the MALDI-TOF instrument, no peaks were found on any target spots, including the quality control. What caused this issue?

Matrix solution was not added to the target wells

When performing sequence-based analysis to identify a bacterial isolate, all of the following must occur to ensure accurate results are obtained EXCEPT?

Mixed cultures can be used as specific sequence is being identified

Which of the following best describes the benefits of the RPR or VDRL tests:

Monitoring course of treatment

Sequence-based testing is most useful in identifying which of the following organisms?

Mycobacterium

Routine culture methods in microbiology rely on the principles of bacterial cultivation and identification. Molecular testing, however, relies on the detection and manipulation of nucleic acids, allowing the microbial genes to be detected instead of the analysis of microbial products (for e.g. enzymes, toxins or identifiable characteristic growth of an organism). One disadvantage to doing molecular testing is?

Need for dedicated space and equipment

All of the following statements about peptide nucleic acid-fluorescence in situ hybridization (PNA-FISH) are true for Staphylococcus EXCEPT?

PNA-FISH assays provide differentiation between Methicillin Resistant Staphylococcus aureus (MRSA) and Methicillin Sensitive Staphylococcus aureus (MSSA)

Matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) is used for identification of aerobic bacterial isolates on a urine culture bench. Upon placing the target into the MALDI-TOF instrument, no peaks were found on one of the patient samples (out of 20 patients). The quality control passed. What caused this issue?

Patient sample was not added to the well

Which of the following is a key benefit that molecular methods can offer over culture methods?

Reduced turnaround time

Sequence-based analysis is an alternate method used to identify bacteria and fungal isolates. This methodology uses rRNA genes (rDNA) and their intergenic regions as common target sites to identify these organisms. Which of the following rRNA gene target sites is used to identify fungal isolates?

28S rRNA

Gas-liquid chromatography is useful in the identification of anaerobes in addition to Gram-stain morphology. Which anaerobe produces succinic acid in abundance?

Actinomyces israelii

What are the four nitrogenous bases that are found in RNA?

Adenine, guanine, cytosine, and uracil

Which derivative of PCR testing uses short primers not specifically complementary to a particular sequence of a target DNA?

Arbitrary primed PCR

All of the following statements are associated with MALDI-TOF mass spectrophotometry used in clinical microbiology, EXCEPT?

Bacteria is amplified using a laser.

All of the following are commercial methodologies that Chlamydia and Neisseria identification have been based on?

Branched chain DNA technology

Matrix-assisted laser desorption-ionization time-of-flight (MALDI-TOF) is used for identification of aerobic bacterial isolates on a urine culture bench. Upon placing the target into the MALDI-TOF instrument, no peaks were found on the quality control wells, but the patient isolates gave good identifications. What caused this issue?

Quality control organism was not added to the target wells

A combination of nontreponemal testing (VDRL or RPR) and treponemal testing (TP-PA or EIA) is used to confirm:

Syphilis

The VDRL and RPR are used to provide presumptive identification of which infection?

Syphilis

What are the two general categories of nucleic acid amplification (NAA) techniques?

Target amplification and signal amplification

Molecular methods offer improvements in sensitivity, but they are dependent upon what factor?

The availability of specific instrumentation

What is successful molecular identification of methicillin-resistant Staphylococcus aureus (MRSA) based upon?

The detection of the S. aureus genes (orfX, nuc, or coa) gene and the mecA gene.