Evaluation of Phenotypic and Molecular Methods for Identification of
            <i>Streptococcus Pneumoniae</i>

Yahiaoui, Rachid; Heijer, Casper D. J. den; Wolfs, Petra; Bruggeman, Cathrien A.; Stobberingh, Ellen E.

doi:10.2217/fmb.15.124

Cited by 15 publications

(15 citation statements)

References 39 publications

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“…Conversely, Yahiaoui et al . recently recommended a new identification protocol, excluding the optochin susceptibility test, and instead recommending only the use of the bile solubility test for species identification 21 .…”

Section: Discussionmentioning

confidence: 99%

“…However it has to be emphasized that if the requirement described in the flowchart cannot be achieved for an isolate, other tests are needed for species identification 6 . As additional information, it has recently been recommended that the optochin test used by many diagnostic laboratories today as a part of routine identification of S. pneumoniae , is not used for the identification of S. pneumoniae 21 . The presented methods can therefore be seen as alternatives to the optochin test.…”

Section: Discussionmentioning

confidence: 99%

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Assessment of a novel bile solubility test and MALDI-TOF for the differentiation of Streptococcus pneumoniae from other mitis group streptococci

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Facklam

Fuursted

2017

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This study assesses a novel bile solubility test and MALDI-TOF for the differentiation of Streptococcus pneumoniae from other mitis group streptococci, including differentiation of S. pneumoniae from Streptococcus pseudopneumoniae. Eighty-four species verified mitis group isolates were subjected to our bile solubility test (which measures and calculates the differences of absorbance in the test tube containing 10% sodium deoxycholate versus a blank control tube, after incubation for 10 minutes at 36 °C using a spectrophotometer) and MALDI-TOF MS (both the standard result output and by visual spectra evaluation). Applying a calculated optimal cut-off absorbance-value of 2.1, differentiated S. pneumoniae from all but one other mitis group streptococci (one S. mitis isolate generated an OD-value above 2.1). MALDI-TOF score value identification identified correctly 46 S. pneumoniae and 4 S. pseudopneumoniae but misidentified 16 other mitis group strains. Visual spectra evaluation correctly identified all S. pneumoniae and S. pseudopneumoniae strains but misidentified 13 other mitis group strains. The bile solubility test based on spectrophotometric reading described in this study can differentiate S. pneumoniae from other Streptococcus species. Combining the bile solubility test and the MALDI-TOF spectra results provide a correct identification of all S. pneumoniae and S. pseudopneumoniae isolates.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Assessment of a novel bile solubility test and MALDI-TOF for the differentiation of Streptococcus pneumoniae from other mitis group streptococci

Slotved

Facklam

Fuursted

2017

Sci Rep

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“…Conventional tests such as optochin sensitivity and bile solubility are still applied in laboratory routine and represent the reference method for the identification of S. pneumoniae isolates (Yahiaoui et al, 2016). However, S. pneumoniae isolates resistant to optochin have been reported in different geographical regions (Nagata et al, 2012) making this tests less than optimal also due to its low specificity (Yahiaoui et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

“…However, S. pneumoniae isolates resistant to optochin have been reported in different geographical regions (Nagata et al, 2012) making this tests less than optimal also due to its low specificity (Yahiaoui et al, 2016). …”

Section: Introductionmentioning

confidence: 99%

Accurate Differentiation of Streptococcus pneumoniae from other Species within the Streptococcus mitis Group by Peak Analysis Using MALDI-TOF MS

et al. 2017

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Despite the benefits of MALDI-TOF MS technology (Matrix-Assisted Laser Desorption-Ionization Time-Of-Flight Mass Spectrometry) reported worldwide and the continuous improving of the available databases, discrimination between Streptococcus pneumoniae and closely related species within the Streptococcus mitis group (SMG) using this methodology has been suboptimal. However, the accurate identification at the species level of this group of microorganisms is important for the appropriate management of infected patients. In this study, 216 SMG isolates -101 S. pneumoniae and 115 corresponding to 7 non-pneumococcal species within this group- were analyzed. All the isolates had been previously identified by conventional methods (optochin and bile solubility tests) and non-pneumococcal isolates were confirmed by sequence analysis (sodA and plys genes) when required. The isolates were also identified with the MALDI Biotyper 3.1 (Bruker Daltonics, Bremen, Germany) using an updated library containing 6,903 Main Spectra Profiles (MSPs). All the analyzed S. pneumoniae were correctly identified with MALDI-TOF MS at species level using the most updated database and all the non-pneumococcal SMG isolates were also identified at the group level. Several peaks (4,964.32, 6,888.90, and 9,516.46 m/z) have been found to be specific of S. pneumoniae, whilst a different set of peaks have proved to be present only in S. mitis (6,839.07 m/z) and S. oralis (5,297.61, 5822.53, and 6,839.07 m/z). Peak analysis allowed correct species assignment of 101/101 S. pneumoniae isolates (100%) and 102/105 S. mitis/oralis isolates (97.1%). Thus, the implementation of MALDI-TOF MS plus peak analysis for the identification of this group of microorganisms may provide precise species-level information that will allow the early implementation of directed antibiotic therapy.

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“…However, a growing problem for many microbiological laboratories is the separation of S. pneumoniae from other species within the viridans group 29 . For example a method such as optochin susceptibility has recently been recommended not to be used for confirming S. pneumoniae due to increasing number of optochin resistance pneumococcal isolates 30 . It is therefore essential that isolates used in an EQA are properly identified as S. pneumoniae .…”

Section: Discussionmentioning

confidence: 99%

External Quality Assurance for Laboratory Identification and Capsular Typing of Streptococcus pneumoniae

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Sheppard

Dalby

et al. 2017

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An external quality assessment (EQA) scheme for pneumococcal serotype identification has been performed over a period of 11 years, by a network of European pneumococcal reference laboratories. We report the results from the EQA, and present an assessment of the acceptability and utility of the EQA scheme. Reports from 22 EQA panels distributed in 2005–2016 were analysed. Each EQA panel consisted of seven isolates. A questionnaire including seven questions related to the acceptability and utility of the EQA scheme was distributed to all participating laboratories. Altogether, 154 pneumococcal isolates were tested. Of the 92 serologically distinct serotypes currently defined, 49 serotypes were included in the rounds. Discrepant results were observed in eight EQA rounds, involving 11 isolates (7.1%, 95% CI: 4% to 12%). All participating laboratories reported that the EQA scheme was useful for quality assurance purposes. Our results show that comparable serotyping data can be obtained in different laboratories. The EQA participation helps to keep the typing procedures at a high standard and provides data for accreditation purposes. The EQA is helpful when new technologies are introduced, and reveal limitations of both genotypic and phenotypic methods. Continuation of the presented EQA scheme is planned.

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Evaluation of Phenotypic and Molecular Methods for Identification of Streptococcus Pneumoniae

Abstract: We demonstrated the failure of the current S. pneumoniae identification methods and optochin susceptibility-based algorithm. In addition, the high rate of optochin resistance might justify the necessity of a close monitoring of optochin susceptibility.

Cited by 15 publications

References 39 publications

Assessment of a novel bile solubility test and MALDI-TOF for the differentiation of Streptococcus pneumoniae from other mitis group streptococci

Assessment of a novel bile solubility test and MALDI-TOF for the differentiation of Streptococcus pneumoniae from other mitis group streptococci

Accurate Differentiation of Streptococcus pneumoniae from other Species within the Streptococcus mitis Group by Peak Analysis Using MALDI-TOF MS

External Quality Assurance for Laboratory Identification and Capsular Typing of Streptococcus pneumoniae

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