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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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MALDI-TOF mass spectra for Enterococcus isolates.16S rRNA gene analysis indicated that isolates S15 and S44 are the same species (E. hirae). However the protein fingerprints were not quite the same. The identification result using Biotyper software is shown at the top-right corner followed by the strain designations.
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pone-0038515-g004: MALDI-TOF mass spectra for Enterococcus isolates.16S rRNA gene analysis indicated that isolates S15 and S44 are the same species (E. hirae). However the protein fingerprints were not quite the same. The identification result using Biotyper software is shown at the top-right corner followed by the strain designations.

Mentions: Important clinical infections are caused by some Enterococcus species including urinary tract infections, diverticulitis, and meningitis [32]. IMO regulations have specified that the concentration of intestinal enteroccoci in discharged ballast water should not exceed 250 cfu 100 ml−1[6]. In our study, three isolates from the North Sea were identified as species of Enterococcus (Table 1). Using 16S rRNA gene sequences, isolates S15 and S44 were both identified as E. hirae. However, using the MTB method, only isolate S44 was identified as E. hirae while isolate S15 was found to be E. faecalis. Figure 4 shows clear differences between the protein fingerprints of these two isolates. Additionally, there are more similarities between the mass spectra of isolates S16 and S44 than between isolates S44 and S15. This is an example of the higher discriminatory power of MTB over 16S rRNA gene analysis. The approach used here also demonstrated that the sample of ballast water used would have passed IMO regulatory restrictions.


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)

MALDI-TOF mass spectra for Enterococcus isolates.16S rRNA gene analysis indicated that isolates S15 and S44 are the same species (E. hirae). However the protein fingerprints were not quite the same. The identification result using Biotyper software is shown at the top-right corner followed by the strain designations.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0038515-g004: MALDI-TOF mass spectra for Enterococcus isolates.16S rRNA gene analysis indicated that isolates S15 and S44 are the same species (E. hirae). However the protein fingerprints were not quite the same. The identification result using Biotyper software is shown at the top-right corner followed by the strain designations.
Mentions: Important clinical infections are caused by some Enterococcus species including urinary tract infections, diverticulitis, and meningitis [32]. IMO regulations have specified that the concentration of intestinal enteroccoci in discharged ballast water should not exceed 250 cfu 100 ml−1[6]. In our study, three isolates from the North Sea were identified as species of Enterococcus (Table 1). Using 16S rRNA gene sequences, isolates S15 and S44 were both identified as E. hirae. However, using the MTB method, only isolate S44 was identified as E. hirae while isolate S15 was found to be E. faecalis. Figure 4 shows clear differences between the protein fingerprints of these two isolates. Additionally, there are more similarities between the mass spectra of isolates S16 and S44 than between isolates S44 and S15. This is an example of the higher discriminatory power of MTB over 16S rRNA gene analysis. The approach used here also demonstrated that the sample of ballast water used would have passed IMO regulatory restrictions.

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