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Characterization of bacteria in ballast water using MALDI-TOF mass spectrometry.

Emami K, Askari V, Ullrich M, Mohinudeen K, Anil AC, Khandeparker L, Burgess JG, Mesbahi E - PLoS ONE (2012)

Bottom Line: To evaluate a rapid and cost-effective method for monitoring bacteria in ballast water, several marine bacterial isolates were characterized by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS).Seawater samples collected from the North Sea were incubated in steel ballast tanks and the presence of potentially harmful species of Pseudomonas was also investigated.At the genus-level, the identification of thirty six isolates using MALDI-TOF MS produced similar results to those obtained by 16S rRNA gene sequencing.

View Article: PubMed Central - PubMed

Affiliation: School of Biology, Newcastle University, Newcastle upon Tyne, United Kingdom. kaveh.emami@ncl.ac.uk

ABSTRACT
To evaluate a rapid and cost-effective method for monitoring bacteria in ballast water, several marine bacterial isolates were characterized by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Since International Maritime Organization (IMO) regulations are concerned with the unintended transportation of pathogenic bacteria through ballast water, emphasis was placed on detecting species of Vibrio, enterococci and coliforms. Seawater samples collected from the North Sea were incubated in steel ballast tanks and the presence of potentially harmful species of Pseudomonas was also investigated. At the genus-level, the identification of thirty six isolates using MALDI-TOF MS produced similar results to those obtained by 16S rRNA gene sequencing. No pathogenic species were detected either by 16S rRNA gene analysis or by MALDI-TOF MS except for the opportunistically pathogenic bacterium Pseudomonas aeruginosa. In addition, in house software that calculated the correlation coefficient values (CCV) of the mass spectral raw data and their variation was developed and used to allow the rapid and efficient identification of marine bacteria in ballast water for the first time.

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Related in: MedlinePlus

Heat-map of Pseudoalteromonas (A) and Pseudomonas (B) isolates generated by the Biotyper software.The spectra were split into 8 or 11 groups according to the directory structure. Red colours indicate closely related groups with identical peaks, and blue colours mark non-related groups.
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pone-0038515-g007: Heat-map of Pseudoalteromonas (A) and Pseudomonas (B) isolates generated by the Biotyper software.The spectra were split into 8 or 11 groups according to the directory structure. Red colours indicate closely related groups with identical peaks, and blue colours mark non-related groups.

Mentions: Since the current Biotyper 2.0 database did not contain Pseudoalteromonas spectra and following the identification of isolate S07 by 16S rRNA sequence as Pseudoalteromonas tetraodonis, the spectrum of this isolate was added to the library as Pseudoalteromonas. sp. Consequently, when re-using the Biotyper software some of the previously unknown isolates could be subsequently identified as Pseudoalteromonas sp. (Table 1). A genus-specific peak of m/z 4233±2 was found in all isolates of this group (Fig. 6, panel D). Nearly all ballast water Pseudoalteromonas isolates had peaks at m/z 5092±2, m/z 6072±3, and m/z 5120±4 (Fig. 6). However, the m/z 7100 zone could also be used to discriminate these isolates. Isolates S07 and S36 showed high similarities in their mass-spectra patterns and are therefore likely to be strains of the same species. Isolates S20 and S49, which were related to Pseudoalteromonas by 16S rRNA gene analysis, could not be robustly identified using MTB (Biotyper score <1.7). However, these strains were included in the Pseudoalteromonas group since they showed high overall similarities in their mass spectral patterns with other members of the group (Fig. 6). An overview of the similarities of all the Pseudomonas and Pseudoalteromonas isolates is shown in Fig. 7 as a heat-map.


Characterization of bacteria in ballast water using MALDI-TOF mass spectrometry.

Emami K, Askari V, Ullrich M, Mohinudeen K, Anil AC, Khandeparker L, Burgess JG, Mesbahi E - PLoS ONE (2012)

Heat-map of Pseudoalteromonas (A) and Pseudomonas (B) isolates generated by the Biotyper software.The spectra were split into 8 or 11 groups according to the directory structure. Red colours indicate closely related groups with identical peaks, and blue colours mark non-related groups.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3369924&req=5

pone-0038515-g007: Heat-map of Pseudoalteromonas (A) and Pseudomonas (B) isolates generated by the Biotyper software.The spectra were split into 8 or 11 groups according to the directory structure. Red colours indicate closely related groups with identical peaks, and blue colours mark non-related groups.
Mentions: Since the current Biotyper 2.0 database did not contain Pseudoalteromonas spectra and following the identification of isolate S07 by 16S rRNA sequence as Pseudoalteromonas tetraodonis, the spectrum of this isolate was added to the library as Pseudoalteromonas. sp. Consequently, when re-using the Biotyper software some of the previously unknown isolates could be subsequently identified as Pseudoalteromonas sp. (Table 1). A genus-specific peak of m/z 4233±2 was found in all isolates of this group (Fig. 6, panel D). Nearly all ballast water Pseudoalteromonas isolates had peaks at m/z 5092±2, m/z 6072±3, and m/z 5120±4 (Fig. 6). However, the m/z 7100 zone could also be used to discriminate these isolates. Isolates S07 and S36 showed high similarities in their mass-spectra patterns and are therefore likely to be strains of the same species. Isolates S20 and S49, which were related to Pseudoalteromonas by 16S rRNA gene analysis, could not be robustly identified using MTB (Biotyper score <1.7). However, these strains were included in the Pseudoalteromonas group since they showed high overall similarities in their mass spectral patterns with other members of the group (Fig. 6). An overview of the similarities of all the Pseudomonas and Pseudoalteromonas isolates is shown in Fig. 7 as a heat-map.

Bottom Line: To evaluate a rapid and cost-effective method for monitoring bacteria in ballast water, several marine bacterial isolates were characterized by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS).Seawater samples collected from the North Sea were incubated in steel ballast tanks and the presence of potentially harmful species of Pseudomonas was also investigated.At the genus-level, the identification of thirty six isolates using MALDI-TOF MS produced similar results to those obtained by 16S rRNA gene sequencing.

View Article: PubMed Central - PubMed

Affiliation: School of Biology, Newcastle University, Newcastle upon Tyne, United Kingdom. kaveh.emami@ncl.ac.uk

ABSTRACT
To evaluate a rapid and cost-effective method for monitoring bacteria in ballast water, several marine bacterial isolates were characterized by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Since International Maritime Organization (IMO) regulations are concerned with the unintended transportation of pathogenic bacteria through ballast water, emphasis was placed on detecting species of Vibrio, enterococci and coliforms. Seawater samples collected from the North Sea were incubated in steel ballast tanks and the presence of potentially harmful species of Pseudomonas was also investigated. At the genus-level, the identification of thirty six isolates using MALDI-TOF MS produced similar results to those obtained by 16S rRNA gene sequencing. No pathogenic species were detected either by 16S rRNA gene analysis or by MALDI-TOF MS except for the opportunistically pathogenic bacterium Pseudomonas aeruginosa. In addition, in house software that calculated the correlation coefficient values (CCV) of the mass spectral raw data and their variation was developed and used to allow the rapid and efficient identification of marine bacteria in ballast water for the first time.

Show MeSH
Related in: MedlinePlus