Abstract
Introduction
One of the most frequent causes of morbidity and mortality in cancer patients is urinary tract infection (UTI). Rapid UTI diagnosis is essential to avoid delay in cancer treatment. Overnight urine culture is required for bacterial identification using MALDI-TOF MS. To shorten the turnaround time, studies are investigating the possibility of using direct urine samples for MALDI-TOF MS. Herein, this study proposed that the low-frequency sonication treatment could be used to improve the sensitivity of the MALDI-TOF MS for bacterial identification from direct urine samples.
Materials and methods
Urine samples were spiked with 3.0 x 108 CFU/mL of Staphylococcus aureus. Prior to direct identification by MALDI-TOF MS, the spiked urine samples were pre-treated with low-frequency sonication at 45 kHz and 37°C with different powers (80w, 140w and 200w) and durations (5, 10 and 15 min). The impact of sonication on bacteria identification was assessed by the MS score and the bacteria counts.
Results
Our study demonstrated significant improvement in the sensitivity of the MALDI-TOF MS with low power sonication (80w) at short durations of 5 and 10 mins resulting the enhanced MS scores by 20% and 27% respectively compared to the direct urine samples without sonication. Interestingly, a prolonged sonication at 15 mins resulted in only a 12% MS score improvement. The bacterial counts remained unchanged among all setups indicating the sonication pre-treatment has no killing effect to S. aureus.
Conclusion
The findings revealed that low-frequency and low-power sonication pre-treatment was able to improve MALDI-TOF MS identification of S. aureus from direct urine by shorten the overnight culture. However, our results may not be extrapolated to other urobacteria due to the varied structural characteristics of bacteria. To better understand how the low-frequency sonication pre-treatment affects MALDI-TOF MS identification of other bacteria, more study is required.
One of the most frequent causes of morbidity and mortality in cancer patients is urinary tract infection (UTI). Rapid UTI diagnosis is essential to avoid delay in cancer treatment. Overnight urine culture is required for bacterial identification using MALDI-TOF MS. To shorten the turnaround time, studies are investigating the possibility of using direct urine samples for MALDI-TOF MS. Herein, this study proposed that the low-frequency sonication treatment could be used to improve the sensitivity of the MALDI-TOF MS for bacterial identification from direct urine samples.
Materials and methods
Urine samples were spiked with 3.0 x 108 CFU/mL of Staphylococcus aureus. Prior to direct identification by MALDI-TOF MS, the spiked urine samples were pre-treated with low-frequency sonication at 45 kHz and 37°C with different powers (80w, 140w and 200w) and durations (5, 10 and 15 min). The impact of sonication on bacteria identification was assessed by the MS score and the bacteria counts.
Results
Our study demonstrated significant improvement in the sensitivity of the MALDI-TOF MS with low power sonication (80w) at short durations of 5 and 10 mins resulting the enhanced MS scores by 20% and 27% respectively compared to the direct urine samples without sonication. Interestingly, a prolonged sonication at 15 mins resulted in only a 12% MS score improvement. The bacterial counts remained unchanged among all setups indicating the sonication pre-treatment has no killing effect to S. aureus.
Conclusion
The findings revealed that low-frequency and low-power sonication pre-treatment was able to improve MALDI-TOF MS identification of S. aureus from direct urine by shorten the overnight culture. However, our results may not be extrapolated to other urobacteria due to the varied structural characteristics of bacteria. To better understand how the low-frequency sonication pre-treatment affects MALDI-TOF MS identification of other bacteria, more study is required.
Original language | English |
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Pages (from-to) | S1461-S1461 |
Number of pages | 1 |
Journal | Annals of Oncology |
Volume | 34 |
Issue number | S3 |
DOIs | |
Publication status | Published - 14 Nov 2023 |