Potential of Elateriospermum tapos blume extract as conjugation inhibitor for preventing dissemination of tetracycyline resistance gene transfer
Dissemination of antibiotic resistance has caused major threat to human health especially in causing hospital-acquired infections. Horizontal gene transfer, mainly conjugation is the responsible transfer mechanism of antibiotic resistance genes among antibiotic resistant bacteria. The search for...
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| Format: | Thesis |
| Language: | English |
| Published: |
2021
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/113798/1/113798.pdf |
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| Summary: | Dissemination of antibiotic resistance has caused major threat to human health
especially in causing hospital-acquired infections. Horizontal gene transfer,
mainly conjugation is the responsible transfer mechanism of antibiotic resistance
genes among antibiotic resistant bacteria. The search for specific compounds or
molecules that are able to inhibit conjugation is therefore significant for
preventing antibiotic resistance gene transfer. Unsaturated fatty acids
specifically oleic, linoleic and alpha-linolenic acids are known as conjugation
inhibitors due to their conjugation inhibition ability, although most of the
previous studies used synthetic unsaturated fatty acids. In this study,
Elateriospermum tapos seed oil (ETSO) with high unsaturated fatty acids
composition was obtained using Soxhlet extraction method and used to
determine its potential in preventing conjugal transfer of tetracycline resistantgene
(tetM). Antimicrobial susceptibility testing was carried out to determine
resistance profiles of bacterial strains prior to conjugation assay. Filter mating
experiment between Lactococcus garvieae KHS-97051, Enterococcus faecalis JH2-2,
Clostridium difficile ribotype 014 and Enterococcus faecalis ATCC 51299 were
conducted to determine suitable donor and recipient cells for conjugation
inhibition study. Successful transfer of tet(M) gene in transconjugants was
confirmed by colony re-streaking, Gram-staining and polymerase chain reaction
(PCR). E. faecalis JH2-2 transconjugants conferring tet(M) resistance were
produced from mating between L. garvieae KHS-97051 donor and E. faecalis JH2-
2 recipient. Transfer frequency decreased from (6.11 ± 1.80) x 10-6 to (5.99 ± 3.44)
x 10-10 transconjugant per donor and (5.85 ± 1.58) x 10-8 to (5.89 ± 2.31) x 10-10
transconjugant per recipient after exposed to ETSO. Transconjugant colonies
following ETSO exposure was reduced from 163 to 9 colonies with 94.48% of
conjugation inhibition. Although, no transconjugant was observed from two
conjugation sets of C. difficile donor and E. faecalis JH2-2 and E. faecalis ATCC
51299 recipients proven that mating is a donor-recipient specific event. Scanning
(SEM) and transmission electron microscopy (TEM) were used to identify the
effects of ETSO exposure towards donor and recipient cells during conjugation.
The average size of pili produced from control and ETSO exposed mating cells
were 0.213 ± 0.029 and 0.093 ± 0.042 μm, respectively hence demonstrated that
there is significant difference between the two groups. Aside from conjugative
pili, there was no appearance of short, numerous attachment pili known as
fimbriae on the cell surface of both cells. However, less cell-to-cell contact and
pili formations were captured in the exposed donor and recipient cells. Smooth
continuous cell wall and membrane of non-exposed recipient cell was observed
but the cell thickness increased in the exposed recipient cell. There was no
difference in cell diameter before and after ETSO exposure. No damaging effects
were observed towards the exposed cells. The COIN potential of ETSO
highlighted in this study will extend the current knowledge on the antimicrobial
resistance in bacteria and enable the future development of a promising
alternative bottom-up strategy to control the emergence and spread of
antimicrobial-resistant bacteria. |
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