Identification of Enterobacteriaceae by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using the VITEK MS system

Richter, Sandra; Sercia, Linda; Branda, John A.; Burnham, Carey‐Ann D.; Bythrow, Maureen; Ferraro, Mary Jane; Garner, Omai B.; Ginocchio, Christine C.; Jennemann, Rebecca; Lewinski, Michael A.; Manji, Ryhana; Mochon, A. Brian; Rychert, Jenna; Westblade, Lars F.; Procop, Gary W.

doi:10.1007/s10096-013-1912-y

Cited by 94 publications

(58 citation statements)

References 28 publications

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“…After either motility induction or sample concentration through vacuum drying, these difficult-to-culture strains were identified successfully. We also found that CHCA, which often was used as a matrix for biotyping microorganisms (27)(28)(29), did not give as high a confidence (Mascot score) as DHB. This may be attributed to the clumps or hot spots (29) formed by DHB crystals which emit strong signals upon contact with laser energy.…”

Section: Discussionmentioning

confidence: 85%

“…We also found that CHCA, which often was used as a matrix for biotyping microorganisms (27)(28)(29), did not give as high a confidence (Mascot score) as DHB. This may be attributed to the clumps or hot spots (29) formed by DHB crystals which emit strong signals upon contact with laser energy. Thus, DHB was selected as the matrix for clinical sample testing, although the hot spots were reported to have reproducibility problems in other applications (23,24).…”

Section: Discussionmentioning

confidence: 85%

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Rapid, Sensitive, and Specific Escherichia coli H Antigen Typing by Matrix-Assisted Laser Desorption Ionization–Time of Flight-Based Peptide Mass Fingerprinting

et al. 2015

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i Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has gained popularity in recent years for rapid bacterial identification, mostly at the genus or species level. In this study, a rapid method to identify the Escherichia coli flagellar antigen (H antigen) at the subspecies level was developed using a MALDI-TOF MS platform with high specificity and sensitivity. Flagella were trapped on a filter membrane, and on-filter trypsin digestion was performed. The tryptic digests of each flagellin then were collected and analyzed by MALDI-TOF MS through peptide mass fingerprinting. Sixty-one reference strains containing all 53 H types and 85 clinical strains were tested and compared to serotyping designations. Wholegenome sequencing was used to resolve conflicting results between the two methods. It was found that DHB (2,5-dihydroxybenzoic acid) worked better than CHCA (␣-cyano-4-hydroxycinnamic acid) as the matrix for MALDI-TOF MS, with higher confidence during protein identification. After method optimization, reference strains representing all 53 E. coli H types were identified correctly by MALDI-TOF MS. A custom E. coli flagellar/H antigen database was crucial for clearly identifying the E. coli H antigens. Of 85 clinical isolates tested by MALDI-TOF MS-H, 75 identified MS-H types (88.2%) matched results obtained from traditional serotyping. Among 10 isolates where the results of MALDI-TOF MS-H and serotyping did not agree, 60% of H types characterized by whole-genome sequencing agreed with those identified by MALDI-TOF MS-H, compared to only 20% byserotyping. This MALDI-TOF MS-H platform can be used for rapid and cost-effective E. coli H antigen identification, especially during E. coli outbreaks. Escherichia coli food contamination can have serious consequences, such as hemolytic-uremic syndrome (HUS) (1, 2), with the 2011 Germany E. coli outbreak presenting a clear example (3). Therefore, the fast identification and typing of E. coli is important for tracking sources of contamination and reducing health risks. Traditional typing of E. coli is based mainly on two surface antigens of the bacteria for antiserum-based agglutination reactions: lipopolysaccharide (LPS) or O antigens for O typing and flagellar proteins or H antigens for H typing (4). The procedure for performing serotyping is time-consuming (2 to 12 days) and barely meets the need for fast diagnosis in outbreak situations. This is mainly due to the need to induce flagellar growth for optimizing agglutination reactions for H antigens. In addition, since there are many serotypes of H antigens, multiple agglutination steps have to be performed. There are 53 H types of E. coli flagella in total (designated H1 to H56; H13, H22, and H50 no longer exist) (4, 5). They are composed of polymerized flagellin proteins, each with an average molecular mass of approximately 50 kDa (36 to 60 kDa).Since H antigens take longer to be typed with antisera, flagellar gene-based molecular methods, such as PCR-based flagellar gene sequen...

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Section: Discussionmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 85%

Rapid, Sensitive, and Specific Escherichia coli H Antigen Typing by Matrix-Assisted Laser Desorption Ionization–Time of Flight-Based Peptide Mass Fingerprinting

et al. 2015

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“…Richter et al evaluated 965 routinely encountered Enterobacteriaceae and showed that VITEK MS correctly identified 97% and 84% of the Enterobacteriaceae studied to the genus and species levels, respectively (20 ). Manji et al showed that the VITEK MS correctly identified 91% and 78% of 558 non-Enterobacteriaceae gram-negative bacilli to the genus and species levels, respectively (21 ).…”

Section: Performance Of Maldi-tof Ms For Identification Of Aerobic Bamentioning

confidence: 99%

MALDI-TOF MS for the Diagnosis of Infectious Diseases

2015

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BACKGROUND:First introduced into clinical microbiology laboratories in Europe, MALDI-TOF MS is being rapidly embraced by laboratories around the globe. Although it has multiple applications, its widespread adoption in clinical microbiology relates to its use as an inexpensive, easy, fast, and accurate method for identification of grown bacteria and fungi based on automated analysis of the mass distribution of bacterial proteins.CONTENT: This review provides a historical perspective on this new technology. Modern applications in the clinical microbiology laboratory are reviewed with a focus on the most recent publications in the field. Identification of aerobic and anaerobic bacteria, mycobacteria, and fungi are discussed, as are applications for testing urine and positive blood culture bottles. The strengths and limitations of MALDI-TOF MS applications in clinical microbiology are also addressed.

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“…All workup of clinically significant organisms was performed in accordance with the package insert for the chromID media. Clinically significant organisms were identified using Vitek MS v2.0 (bioMérieux) directly from conventional or chromID media (11)(12)(13)15). During each step of work-up and identification, hands-on time and consumable usage were documented for both conventional and chromogenic methods using a stopwatch.…”

Section: Subjectsmentioning

confidence: 99%

“…This method has been shown to be accurate and cost-effective for identification of bacterial and fungal organisms (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). However, considerable hands-on time may be necessary upstream of MALDI-TOF MS to isolate significant uropathogens from standard media, particularly for patients with mixed infections.…”

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confidence: 99%

Culture of Urine Specimens by Use of chromID CPS Elite Medium Can Expedite Escherichia coli Identification and Reduce Hands-On Time in the Clinical Laboratory

et al. 2016

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Urine is one of the most common specimen types submitted to the clinical microbiology laboratory; the use of chromogenic agar is one method by which the laboratory might expedite culture results and reduce hands-on time and materials required for urine culture analysis. The objective of our study was to compare chromID CPS Elite (bioMérieux), a chromogenic medium, to conventional primary culture medium for evaluation of urine specimens. Remnant urine specimens (n ‫؍‬ 200) were inoculated into conventional media and into chromID CPS Elite agar (chromID). The time to identification and consumables used were documented for both methods. Clinically significant pathogen(s) were recovered from 51 cultures using conventional media, with Escherichia coli being the most frequently recovered organism (n ‫؍‬ 22). The rate of exact uropathogen agreement between conventional and chromogenic media was 82%, while overall categorical agreement was 83.5% The time interval between plating and final organism identification was decreased with chromID agar versus conventional media for E. coli (mean of 24.4 h versus 27.1 h, P < 0.001). Using chromID, clinically significant cultures required less hands-on time per culture (mean of 1 min and 2 s [1:02 min]) compared to conventional media (mean of 1:31 min). In addition, fewer consumables (2.4 versus 3.3 sticks and swabs) and rapid biochemical tests (1.0 versus 1.9) were necessary using chromID versus conventional media. Notably, antimicrobial susceptibility testing demonstrated good overall agreement (97.4%) between the chromID and conventional media for all antibiotics tested. chromID CPS Elite is accurate for uropathogen identification, reduces consumable usage, and may expedite the identification of E. coli in clinical specimens. U rinary tract infections (UTIs) are among the most common bacterial infections worldwide (1). Screening urine cultures to identify significant uropathogens can require considerable hands-on time, consumable usage, and biochemical testing. As a result, urine cultures to support a diagnosis of UTI account for a major share of the workload in microbiology laboratories (2), which are facing a shortage of skilled laboratory personnel (3). Thus, there is a need for accurate methods that save time and reduce workload. In addition, there is growing emphasis on expediting culture results from patients with infection; minimizing the window of diagnostic uncertainty is essential to optimize antimicrobial therapy and improve patient outcomes (4).One approach to streamline urine culture is the rapid identification of organisms from growth on solid agar using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). This method has been shown to be accurate and cost-effective for identification of bacterial and fungal organisms (5-15). However, considerable hands-on time may be necessary upstream of MALDI-TOF MS to isolate significant uropathogens from standard media, particularly for patients with mixed infections.The majority of com...

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Identification of Enterobacteriaceae by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry using the VITEK MS system

Cited by 94 publications

References 28 publications

Rapid, Sensitive, and Specific Escherichia coli H Antigen Typing by Matrix-Assisted Laser Desorption Ionization–Time of Flight-Based Peptide Mass Fingerprinting

Rapid, Sensitive, and Specific Escherichia coli H Antigen Typing by Matrix-Assisted Laser Desorption Ionization–Time of Flight-Based Peptide Mass Fingerprinting

MALDI-TOF MS for the Diagnosis of Infectious Diseases

Culture of Urine Specimens by Use of chromID CPS Elite Medium Can Expedite Escherichia coli Identification and Reduce Hands-On Time in the Clinical Laboratory

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