Dataset Information

Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry for rapid detection of ?-lactam resistance in Enterobacteriaceae derived from blood cultures.

ABSTRACT: The identification of pathogens directly from blood cultures by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) can be a valuable tool for improving the treatment of patients with sepsis and bacteremia. However, the increasing incidence of multidrug-resistant Gram-negative bacteria makes it difficult to predict resistance patterns based only on pathogen identification. Most therapy regimens for sepsis caused by Gram-negative rods consist of at least one ?-lactam antibiotic. Thus, it would be of great benefit to have an early marker of resistance against these drugs. In the current study, we tested 100 consecutive blood cultures containing Enterobacteriaceae for resistance against 3rd-generation cephalosporins in a MALDI-TOF MS ?-lactamase assay. Escherichia coli was also tested for resistance against aminopenicillins. The results of the ?-lactamase assay were compared with those of conventional methods. The assay permitted discrimination between E. coli strains that were resistant or susceptible to aminopenicillins with a sensitivity and a specificity of 100%. The same was true for resistance to 3rd-generation cephalosporins in Enterobacteriaceae that constitutively produced class C ?-lactamases. Discrimination was more difficult in species expressing class A ?-lactamases, as these enzymes can generate false-positive results. Thus, the sensitivity and specificity for this group were 100% and 91.5%, respectively. The test permitted the prediction of resistance within 2.5 h after the blood culture was flagged as positive.

SUBMITTER: Jung JS

PROVIDER: S-EPMC3957742 | biostudies-literature | 2014 Mar

REPOSITORIES: biostudies-literature

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Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry for rapid detection of β-lactam resistance in Enterobacteriaceae derived from blood cultures.

Jung Jette Sophia JS Popp Christina C Sparbier Katrin K Lange Christoph C Kostrzewa Markus M Schubert Soeren S

Journal of clinical microbiology 20140108 3

The identification of pathogens directly from blood cultures by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) can be a valuable tool for improving the treatment of patients with sepsis and bacteremia. However, the increasing incidence of multidrug-resistant Gram-negative bacteria makes it difficult to predict resistance patterns based only on pathogen identification. Most therapy regimens for sepsis caused by Gram-negative rods consist of at least on ...[more]

PMID: 24403301

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Project description:Streptococcus suis, particularly S. suis serotype 2 (SS2), is an important zoonotic pathogen causing meningitis in humans worldwide. Although the proper classification of the causative and pathogenic serotype is salutary for the clinical diagnosis, cross-reactions leading to the indistinguishability of serotypes by the current serotyping methods are significant limitations. In the present study, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis of extracted peptides was developed to improve the classification of serotype of S. suis. The peptide mass fingerprint (PMFs) database of S. suis was generated from the whole-cell peptides of 32 reference strains of S. suis isolates obtained from pigs. Thirty-two human S. suis isolates from clinical cases in Thailand were used to validate this alternative serotyping method in direct comparison to the multiplex (m)PCR approach. All reference strains, representing 32 serotypes of S. suis, exhibited their individual PMFs patterns, thus allowing differentiation from one another. Highly pathogenic SS2 and SS14 were clearly differentiated from the otherwise serologically closely related SS1/2 and SS1, respectively. The developed MALDI-TOF-MS serotyping method correctly classified the serotype in 68.8% (22/32) of the same serotype isolates generated from the PMFs database; while the validity for the clinical human isolates was 62.5% (20/32). The agreement between the MALDI-TOF-MS and mPCR serotyping was moderate with a Kappa score of 0.522, considering that mPCR could correctly serotype up to 75%. The present study demonstrated that PMFs from the developed MALDI-TOF-MS-based method could successfully discriminate the previously indistinguishable highly pathogenic SS2 and SS14 from SS1/2 and SS1, respectively. Moreover, this serotyping method distinguished pathogenic SS6, and so is an alternative approach of choice to rapidly and reliably serotype clinically pathogenic S. suis isolates.

Dataset Information

Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry for rapid detection of ?-lactam resistance in Enterobacteriaceae derived from blood cultures.

Publications

Evaluation of matrix-assisted laser desorption ionization-time of flight mass spectrometry for rapid detection of β-lactam resistance in Enterobacteriaceae derived from blood cultures.

Similar Datasets

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