TABLE 1.
Summary of results obtained in this study
| Strain name | Strain description | Cultivation conditionsa |
CFU/plate after inactivationb |
No. identified/no. analyzed by MALDI-TOF MS (%)c |
||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Temperature and time | Medium | Direct transfer | 70% ethanol | CHCA matrix | Solvent | Direct transfer | Solvent | Solvent with no centrifugation | ||
| 16M | Brucella melitensis biovar 1, reference strain (ATCC 23456) | 37°C, 48 h | COS-B | 4 | 2 | 0 | 0 | NT | 10/11 (91) | 4/4 (100) |
| 544 | Brucella abortus biovar 1, reference strain (ATCC 23448) | 37°C, 48 h | COS-B | 8 | >200 | 0 | 0 | NT | 6/6 (100) | NT |
| 1330 | Brucella suis biovar 1, reference strain (ATCC 23444) | 37°C, 48 h | COS-B | >200 | 0 | 0 | 0 | NT | 6/6 (100) | NT |
| 513 | Brucella suis biovar 5, reference strain (NCTC 11996) | 37°C, 48 h | COS-B | NT | 0 | 0 | 0 | NT | 6/6 (100) | NT |
| RM6/66 | Brucella canis, reference strain (ATCC 23365) | 37°C, 48 h | COS-B | 2 | 18 | 0 | 0 | NT | 6/6 (100) | NT |
| 5K33 | Brucella neotomae, type strain (ATCC 23459) | 37°C, 48 h | COS-B | 0 | 0 | 0 | 0 | NT | 6/6 (100) | NT |
| BO1 | Brucella inopinata (BCCN 07-01) | 37°C, 24 h | COS-B | 0 | 2 | 0 | 0 | NT | 12/12 (100) | NT |
| BO2 | Brucella inopinata-like | 37°C, 24 h | COS-B | NT | 0 | 0 | 0 | NT | 10/10 (100) | NT |
| CCM4915 | Brucella microti (BCCN 07-01) | 37°C, 24 h | COS-B | 0 | 0 | 0 | 0 | NT | 12/12 (100) | NT |
| F8/08-60 | Brucella papionis (NVSL) | 37°C, 96 h | COS-B | >200 | 0 | 0 | 0 | NT | 4/4 (100) | NT |
| B1/94 | Brucella ceti, reference strain (NCTC 12891) | 37°C, 5% CO2, 96 h | COS-B | NT | 0 | 0 | 0 | NT | 7/8 (88) | 2/2 (100) |
| B2/94 | Brucella pinnipedialis, reference strain (NCTC 12890) | 37°C, 5% CO2, 96 h | COS-B | NT | 10 | 0 | 0 | NT | 4/4 (100) | NT |
| 63/290 | Brucella ovis, reference strain (ATCC 25840) | 37°C, 5% CO2, 96 h | COS-B | NT | NT | NT | NT | NT | 2/2 (100) | NT |
| NF2653 | Brucella spp. (wild rodent, Australia) | 37°C, 24 h | COS-B | NT | NT | NT | 0 | NT | 13/13 (100) | NT |
| bIN1983 | 16M transformed with GFP-encoding plasmid | 37°C, 48 h | COS-B | NT | NT | NT | NT | NT | 7/7 (100) | NT |
| LMG 3301 | Ochrobactrum intermedium | 37°C, 24 h | COS-B | NT | NT | NT | NT | NT | 2/2 (100) | NT |
| ATCC 49188 | Ochrobactrum anthropi | 37°C, 24 h | COS-B | NT | NT | NT | NT | NT | 1/2 (50) | NT |
| BAA-747 | Acinetobacter baumannii (ATCC BAA-747) | 37°C, 24 h | COS-B | NT | NT | NT | NT | 5/5 (100) | 8/9 (89) | 3/4 (75) |
| K56-2 | Burkholderia cenocepacia | 37°C, 24 h | COS-B | NT | NT | NT | NT | 4/5 (80) | 6/6 (100) | 4/4 (100) |
| ATCC 29212 | Enterococcus faecalis | 37°C, 24 h | TSA-S | NT | NT | NT | NT | 4/5 (80) | 4/7 (57) | 4/4 (100) |
| ATCC 25922 | Escherichia coli | 37°C, 24 h | COS-B | NT | NT | NT | NT | 6/7 (86) | 7/10 (70) | 4/4 (100) |
| ATCC 10211 | Haemophilus influenzae | 37°C, 5% CO2, 24 h | CHOC | NT | NT | NT | NT | 4/6 (67) | 6/8 (75) | 4/4 (100) |
| ATCC 19424 | Neisseria gonorrhoeae | 37°C, 5% CO2, 24 h | CHOC | NT | NT | NT | NT | 3/6 (50) | 5/6 (83) | 4/4 (100) |
| ATCC 27853 | Pseudomonas aeruginosa | 37°C, 24 h | COS-B | NT | NT | NT | NT | 7/8 (88) | 9/10 (90) | 4/4 (100) |
| ATCC 14028 | Salmonella enterica serovar Typhimurium, reference strain | 37°C, 24 h | COS-B | NT | NT | NT | NT | 6/6 (100) | 10/10 (100) | 4/4 (100) |
| ATCC 25923 | Staphylococcus aureus | 37°C, 24 h | COS-B | NT | NT | NT | NT | 6/6 (100) | 8/8 (100) | 4/4 (100) |
| LyfoCults | Escherichia coli strain used to calibrate Vitek MS system (ATCC 8739) | 37°C, 24 h | COS-B | NT | NT | NT | NT | 449/464 (97) | 2/2 (100) | NT |
a
Standard cultivation conditions for the bacterial strains used. COS-B, Columbia agar with 5% sheep blood (bioMérieux); TSA-S, trypticase soy agar with 5% sheep blood (Becton, Dickinson); CHOC, chocolate agar with vitox (Oxoid).
b
Efficiency of the indicated inactivation methods with several Brucella strains. Shown are the maximal colony numbers obtained from several independent repeats.
c
Results of identification by MALDI-TOF MS using the direct transfer procedure or the solvent-based method, with or without centrifugation. Shown are the numbers of successful identifications/numbers of spectra analyzed, as well as the rate of success. NT, not tested.