Matrix-Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry for Identification of Microorganisms in Clinical Urine Specimens after Two Pretreatments
, , , oraz | 06 gru 2021
O artykule
Article Category: original-paper
Data publikacji: 06 gru 2021
Zakres stron: 207 - 213
Otrzymano: 26 sty 2021
Przyjęty: 06 kwi 2021
DOI: https://doi.org/10.33073/pjm-2021-018
Słowa kluczowe
© 2021 Deru Lei et al., published by Sciendo
This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Comparison of three methods for identification of Gram-negative bacteria and Gram-positive bacteria.
| Method | Identification results | Total | ||
|---|---|---|---|---|
| Gram-negative bacteria | Gram-positive bacteria | |||
| Conventional urine culture | 170 | 41 | 211 | |
| Centrifugation-based MALDI-TOF MS | 140 | 19 | 159 | |
| Short-term culture combined with MALDI-TOF MS | 155 | 27 | 182 | |
Correlation between colony count and the MALDI-TOF MS identification.
| Germ | Centrifugation-based MALDI-TOF MS No. of cases (%) | Short-term culture combined with MALDI-TOF MS No. of cases (%) | |||
|---|---|---|---|---|---|
| Detected | Detected | ||||
| Yes | No | Yes | No | ||
| ≥ 105 CFU/ml | 133/147 (90.5%) | 14/147 (9.5%) | 137/147 (93.2%) | 10/147 (6.8%) | |
| 104 ~ 105 CFU/ml | 5/15 (33.3%) | 10/15 (66.7%) | 12/15 (80.0%) | 3/15 (20.0%) | |
| ≤ 104 CFU/ml | 2/8 (25.0%) | 6/8 (75.0%) | 6/8 (75.0%) | 2/8 (25.0%) | |
| Total | 140/170 (82.4%) | 30/170 (17.6%) | 155/170 (91.2%) | 15/170 (8.8%) | |
| ≥ 105 CFU/ml | 15/25 (60.0%) | 10/25 (40.0%) | 18/25 (72.0%) | 7/25 (28.0%) | |
| 104 ~ 105 CFU/ml | 3/12 (25.0%) | 9/12 (75.0%) | 8/12 (66.7%) | 4/12 (33.3%) | |
| ≤ 104 CFU/ml | 1/4 (25.0%) | 3/4 (75.0%) | 1/4 (25.0%) | 3/4 (75.0%) | |
| Total | 19/41 (46.3%) | 22/41 (53.7%) | 27/41 (65.9%) | 14/41 (34.1%) | |
| ≥ 105 CFU/ml | 81/87 (93.1%) | 6/87 (6.9%) | 84/87 (96.6%) | 3/87 (3.4%) | |
| 104 ~ 105 CFU/ml | 2/11 (18.2%) | 9/11 (81.8%) | 9/11 (81.8%) | 2/11 (18.2%) | |
| ≤ 104 CFU/ml | 1/2 (50.0%) | 1/2 (50.0%) | 2/2 (100.0%) | 0/2 (0.0%) | |
| Total | 84/100 (84.0%) | 16/100 (16.0%) | 95/100 (95.0%) | 5/100 (5.0%) | |
| ≥ 105 CFU/ml | 5/8 (62.5%) | 3/8 (37.5%) | 6/8 (75.0%) | 2/8 (25.0%) | |
| 104 ~ 105 CFU/ml | 2/5 (40.0%) | 3/5 (60.0%) | 3/5 (60.0%) | 2/5 (40.0%) | |
| ≤ 104 CFU/ml | 0/2 (0.0%) | 2/2 (100.0%) | 1/2 (50.0%) | 1/2 (50.0%) | |
| Total | 7/15 (46.7%) | 8/15 (53.3%) | 10/15 (66.7%) | 5/15 (33.3%) | |
Comparison of MALDI scores between the two methods.
| Germ | Centrifugation-based MALDI-TOF MS | Short-term culture combined with MALDI-TOF MS | |||
|---|---|---|---|---|---|
| score ± SD | RSD | score ± SD | RSD | ||
| Gram-negative bacteria | 2.18 ± 0.25 | 11.4% | 2.14 ± 0.18 | 8.3% | |
| Gram-positive bacteria | 2.10 ± 0.19 | 9.1% | 2.03 ± 0.23 | 11.2% | |
| Total | 2.17 ± 0.24 | 11.2% | 2.09 ± 0.20 | 9.5% | |
Identification results by conventional culture and two MALDI-TOF MS methods.
| Conventional urine culture (No. of cases) | Centrifugation-based MALDI-TOF MS | Short-term culture combined with MALDI-TOF MS | ||||
|---|---|---|---|---|---|---|
| Score > 1.7 (No. of cases) | Score > 2.0 (No. of cases) | Mean Score ± SD | Score > 1.7 (No. of cases) | Score > 2.0 (No. of cases) | Mean Score ± SD | |
| 84 | 75 | 2.22 ± 0.16 | 95 | 87 | 2.17 ± 0.08 | |
| 23 | 18 | 2.16 ± 0.21 | 26 | 22 | 2.18 ± 0.18 | |
| 10 | 8 | 2.18 ± 0.19 | 9 | 6 | 2.04 ± 0.15 | |
| 8 | 7 | 2.14 ± 0.19 | 8 | 6 | 2.09 ± 0.18 | |
| 3 | 2 | 1.95 ± 0.13 | 5 | 5 | 2.24 ± 0.09 | |
| 3 | 3 | 2.27 ± 0.10 | 4 | 4 | 2.26 ± 0.10 | |
| 4 | 4 | 2.22 ± 0.12 | 4 | 4 | 2.23 ± 0.11 | |
| 2 | 1 | 2.14 ± 0.19 | 2 | 1 | 2.03 ± 0.18 | |
| 1 | 1 | 2.09 | 0 | 0 | N/A | |
| 2 | 2 | 2.18 ± 0.16 | 2 | 1 | 2.22 ± 0.28 | |
| 7 | 5 | 2.15 ± 0.19 | 10 | 6 | 2.03 ± 0.20 | |
| 8 | 6 | 2.08 ± 0.17 | 12 | 7 | 2.04 ± 0.24 | |
| 1 | 0 | 2.20 | 2 | 1 | 1.96 ± 0.23 | |
| 0 | 0 | N/A | 1 | 1 | 2.22 | |
| 0 | 0 | N/A | 1 | 0 | 1.76 | |
| 1 | 1 | 2.09 | 1 | 1 | 2.15 | |
| 1 | 1 | 2.20 | 0 | N/A | N/A | |
| 1 | 0 | 1.75 | 0 | N/A | N/A | |
| 0 | 0 | N/A | 0 | 0 | N/A | |
| 0 | 0 | N/A | 0 | 0 | N/A | |
| 0 | 0 | N/A | 0 | 0 | N/A | |
| Total (211) | 159 | 135 | 182 | 153 | ||