Rapid Identification and Drug Sensitivity Test to Urinary Tract Infection Pathogens by DOT-MGA

Abstract

Aim

To reduce the inspection time for urinary tract pathogens and provide a rapid and effective therapeutic plan for clinical anti-infection treatment, this study developed a rapid identification (ID) and antimicrobial sensitivity test (AST) method by DOT-MGA.

Methods

We grouped midstream urine samples with single bacteria according to the number of bacteria (≤5/5–15/≥ 15) under per oil microscope after Gram staining. Then we adopted differential centrifugation to process the grouped samples to collect precipitate. MALDI-TOF MS was performed using precipitate directly or after short-term culture. If succeed, we resuspended the precipitate into droplets with or without antibiotics at a MALDI target. Four hours later, mass spectrometer (MS) was used to identify the culture on the target and to analyse AST.

Results

Samples (count ≥ 15), which precipitate can be directly identified by MS; otherwise, the precipitate need a short-term cultured for 3–6 h before ID. The consistency of the ID results between conventional culture and the precipitate is 100%. Compared with broth microdilution method, DOT-MGA for predicting AST had a high consistency. EA and CA for IPM, LEV, CAZ, NIT, and FOT were 100%/100%, 98%/90%, 98%/92%, 100%/90%, 98%/94%, respectively. No VME was observed in all tests. Besides, MIC50 for the five antibiotics by DOT-MGA and broth microdilution method were ≤1/≤0.5,>2/2,≤4/≤2,≤32/≤16,≤64/≤32 and MIC90 were ≤1/≤0.5, >2/>4, 16/16, 128/128, 128/64.

Conclusion

This study can shorten the ID time (minimum 0.5h) and AST (minimum 4h) of the main pathogens of urinary tract infection to 5–10 hours, which greatly reduce the inspection time and provide substantial help for the rapid diagnosis and treatment of patients with urinary tract infection.

Keywords:

• MALDI-TOF
• DOT-MGA
• rapid drug susceptibility test
• urinary tract infection
• antibiotics resistance

Ethical Approval

This study involved anonymous use of redundant, abandoned patient urine after laboratory testing, with no contact with the patient, and there was no patient identification performed during data collection. This research does not affect patients’ health and privacy. Therefore, the ethics committee determined that informed consent was not required. The Ethics approval was obtained from the medical ethics committee of Anhui Medical University with the following reference number: LLSC20210802.

Author Contributions

All authors made substantial contributions to conception and design, acquisition of data, or analysis and interpretation of data; took part in drafting the article or revising it critically for important intellectual content; agreed to submit to the current journal; gave final approval of the version to be published; and agree to be accountable for all aspects of the work.

Disclosure

The authors report no conflicts of interest in this work.

Additional information

Funding

This work was funded through a grant from Anhui Provincial Department of Education for University cooperative research and public health collaborative innovation project in Anhui Province in 2020 (Grant No. GXXT-2020-016) and a grant from Anhui Provincial Health Commission for key scientific research projects in 2021 (Grant No. AHWJ2021a011) and major natural science research projects of colleges and universities in Anhui Province in 2021 (Grant No. KJ2021ZD0032).