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. 2018 Aug;55(8):3232-3240.
doi: 10.1007/s13197-018-3255-2. Epub 2018 Jun 22.

Identification of Clostridium spp. derived from a sheep and cattle slaughterhouse by matrix-assisted laser desorption and ionization-time of flight mass spectrometry (MALDI-TOF MS) and 16S rDNA sequencing

Farzaneh Bakhtiary  1 , Hamid Reza Sayevand  1 , Marlene Remely  1 , Berit Hippe  1 , Alexander Indra  2 , Hedayat Hosseini  3 , Alexander G Haslberger  1
Affiliations

Identification of Clostridium spp. derived from a sheep and cattle slaughterhouse by matrix-assisted laser desorption and ionization-time of flight mass spectrometry (MALDI-TOF MS) and 16S rDNA sequencing

Farzaneh Bakhtiary et al. J Food Sci Technol. 2018 Aug.

Abstract

Clostridia are widespread and some of them are serious human pathogens. Identification of Clostridium spp. is important for managing microbiological risks in the food industry. Samples derived from sheep and cattle carcasses from a slaughterhouse in Iran were analyzed by MALDI-TOF MS using direct transfer and extended direct transfer sample preparation methods and 16S rDNA sequencing. MALDI-TOF MS could identify ten species in 224 out of 240 Clostridium isolates. In comparison to the 16S rDNA sequencing, correct identification rate of the Clostridium spp. at the species level by MALDI-TOF MS technique was 93.3%. 16 isolates were not identified by MALDI-TOF MS but 16s rDNA sequencing identified them as C. estertheticum, C. frigidicarnis, and C. gasigenes species. The most frequently identified Clostridium species were: C. sporogenes (13%), C. cadaveris (12.5%), C. cochlearium (12%) and C. perfringens (10%). Extended direct transfer method [2.26 ± 0.18 log (score)] in comparison to direct transfer method [2.15 ± 0.23 log (score)] improved Clostridium spp.

Identification: Using a cut-off score of 1.7 was sufficient for accurate identification of Clostridium species. MALDI-TOF MS identification scores for Clostridium spp. decreased with longer incubation time. Clostridium species predominantly were isolated from carcasses after skinning and evisceration steps in the slaughterhouse. MALDI-TOF MS could be an accurate way to identify Clostridium species. Moreover, continuous improvement of the database and MALDI-TOF MS instrument enhance its performance in food control laboratories.

Keywords: 16S rDNA; Clostridium spp.; MALDI-TOF MS; Slaughterhouse.

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Conflict of interest statement

Compliance with ethical standardsThe authors declare that they have no conflict of interest.

Figures

Fig. 1
Fig. 1
Overview of Bruker MALDI-TOF MS identification of Clostridium isolates at the species level. MALDI-TOF MS identified 94% isolates while 6% of isolates were not identified by MALDI-TOF MS. These isolates were identified via 16S rDNA as C. estertheticum (n = 8), C. frigidicarnis (n = 5), and C. gasigenes (n = 3) species
Fig. 2
Fig. 2
Comparing direct transfer and extended direct transfer sample preparation methods for identification of Clostridium species by MALDI-TOF MS at different days of anaerobic incubation (1, 3, and 5). Each isolate was tested three times for each method of sample preparation at each day
Fig. 3
Fig. 3
Results of identification of the Clostridium species according to sampling site a sheep slaughter line, b cattle slaughter line
See this image and copyright information in PMC

References

    1. Adam KH, Flint SH, Brightwell G. Reduction of spoilage of chilled vacuum-packed lamb by psychrotolerant clostridia. Meat Sci. 2013;93(2):310–315. doi: 10.1016/j.meatsci.2012.09.011. - DOI - PubMed
    1. Agustini BC, Silva LP, Bloch C, Jr, Bonfim TMB, et al. Evaluation of MALDI-TOF mass spectrometry for identification of environmental yeasts and development of supplementary database. Appl Microbiol Biotechnol. 2014;98(12):5645–5654. doi: 10.1007/s00253-014-5686-7. - DOI - PubMed
    1. Alispahic M, Christensen H, Hess C, Razzazi-Fazeli E, et al. Identification of Gallibacterium species by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry evaluated by multilocus sequence analysis. Int J Med Microbiol. 2011;301:513–522. doi: 10.1016/j.ijmm.2011.03.001. - DOI - PubMed
    1. AlMogbel MS. Matrix assisted laser desorption/ionization time of flight mass spectrometry for identification of Clostridium species isolated from Saudi Arabia. Braz J Microbiol. 2016;47(2):410–413. doi: 10.1016/j.bjm.2016.01.027. - DOI - PMC - PubMed
    1. Angeletti S. Matrix assisted laser desorption time of flight mass spectrometry (MALDI-TOF MS) in clinical microbiology. J Microbiol Methods. 2017;138:20–29. doi: 10.1016/j.mimet.2016.09.003. - DOI - PubMed