Transcriptomic profiling of ceftriaxone-tolerant phenotypes of Neisseria gonorrhoeae reveals downregulation of ribosomal genes — a pilot study
ABSTRACT Antibiotic tolerance is associated with failure of antibiotic treatment and accelerates the development of antimicrobial resistance. The molecular mechanisms underlying antimicrobial tolerance remain poorly understood. Tolerant bacteria can slow metabolism by extending the lag phase without...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
American Society for Microbiology
2025-08-01
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| Series: | Microbiology Spectrum |
| Subjects: | |
| Online Access: | https://journals.asm.org/doi/10.1128/spectrum.01207-25 |
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| Summary: | ABSTRACT Antibiotic tolerance is associated with failure of antibiotic treatment and accelerates the development of antimicrobial resistance. The molecular mechanisms underlying antimicrobial tolerance remain poorly understood. Tolerant bacteria can slow metabolism by extending the lag phase without altering antimicrobial susceptibility. We recently induced ceftriaxone (CRO) tolerance in the Neisseria gonorrhoeae reference strain WHO P. In the current study, we characterized the transcriptomic profiles of these CRO-tolerant phenotypes. To induce tolerance, WHO P strains were grown under 3-h intermittent CRO exposure (10× the MIC), followed by overnight growth in gonococcal (GC) broth for seven consecutive days, with cultures maintained in sextuplicate. Two control cultures were maintained without CRO exposure. The tolerance and CRO susceptibility of the isolates were assessed using a modified tolerance disc (TD) test. Total RNA was isolated from tolerant isolates (n = 12) and control (n = 3) strains, followed by Ribo depletion, Illumina Library preparation, and sequencing. Transcriptomic analysis revealed no differentially expressed genes after 1 day of CRO exposure. However, after 3 days of CRO exposure, 13 genes were found to be significantly downregulated, including tRNA-Ser (C7S06_RS03100) and tRNA-Leu (C7S06_RS04945) and ribosomal RNA genes (16S and 23S rRNA). Following 7 days of exposure, 51 genes were differentially expressed, with most downregulated, such as SecB (Protein-export chaperone SecB) and tRNA-Ser (C7S06_RS01850) and the 16S and 23S ribosomal RNA genes. The development of CRO-tolerance in N. gonorrhoeae was associated with the downregulation of various ribosomal genes and associated genes, reflecting a potential mechanism for bacterial survival under antibiotic stress.IMPORTANCEAntibiotic tolerance allows some bacteria to survive antibiotic treatment, contributing to treatment failure and creating conditions that promote resistance. In this study, we showed that Neisseria gonorrhoeae, the bacteria that causes gonorrhea, can become tolerant to ceftriaxone—the last-line treatment used. By repeatedly exposing the bacteria to high doses of ceftriaxone, we observed the development of tolerance over several days. Using transcriptomic analysis, we found that tolerant bacteria consistently reduced the activity of genes involved in protein synthesis, including ribosomal RNAs and transfer RNAs. This suggests that N. gonorrhoeae may survive antibiotic stress by entering a low-metabolic state that makes the antibiotic less effective. These findings highlight a survival mechanism that does not rely on genetic resistance. Understanding this tolerance response is vital for improving current treatment approaches and could inform the development of new strategies to prevent antibiotic failure in gonorrhea and other infections. |
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| ISSN: | 2165-0497 |