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BMC Microbiology, Springer Nature
gyrA ser83
mutation among fluoroquinolone-resistant Salmonella enterica serovars
from enteric fever patients in tertiary care hospital, Kathmandu
Prashanna Adhikari, Roshani Maharjan, Subash Paudel, Bikram Malla, Pradeep Kumar Shah, Anup Bastola & Upendra Thapa Shrestha*
* Corresponding author:
Upendra Thapa Shrestha, Faculty, Central Department of Microbiology, Tribhuvan
University, Kirtipur, Kathmandu, Nepal. Email: upendrats@gmail.com
BMC
Microbiology volume 22, Article number: 51 (2022)
https://doi.org/10.1186/s12866-022-02456-7
ABSTRACT
Background
The management of enteric
fever through antibiotics is difficult these days due to the emerging
resistance of Salmonella to various antimicrobial agents. The
development of antimicrobial resistance is associated with multiple factors
including mutations in the specific genes. To know the current status of
mutation-mediated fluoroquinolone-resistance among Salmonella enterica serovars;
Typhi, Paratyphi A, B and C, this study was focused on detecting gyrA ser83
mutation by restriction digestion analysis of gyrA gene
using HinfI endonuclease.
Results
A total of 948 blood samples
were processed for isolation of Salmonella spp. and 3.4% of
them were found to be positive for Salmonella growth. Out of
the 32 Salmonella isolates, 2.2% were S. Typhi and
1.2% were S. Paratyphi A. More interestingly, we observed
less than 5% of isolates were resistant to first-line drugs including
chloramphenicol, cotrimoxazole and ampicillin. More than 80% of isolates were
resistant to fluoroquinolones accounting for 84.4% to levofloxacin followed by
87.5% to ofloxacin and 100% to ciprofloxacin by disc diffusion methods.
However, the minimum inhibitory concentration method using agar dilution showed
only 50% of isolates were resistant to ciprofloxacin. A total of 3.1% of
isolates were multidrug-resistant. Similarly, 90.6% of the Salmonella isolates
showed gyrA ser83 mutation with resistance to nalidixic acid.
Conclusions
The increased resistance to fluoroquinolones and
nalidixic acid in Salmonella isolates in our study suggests
the use of alternative drugs as empirical treatment. Rather, the treatment
should focus on prescribing first-line antibiotics since we observed less than
5% of Salmonella isolates were resistant to these drugs.
Keywords: Enteric fever, Salmonella enterica, Fluoroquinolone-resistant, gyrA, ser83 mutation
Citation: Adhikari et al., gyrA ser83 mutation among fluoroquinolone-resistant Salmonella enterica serovars from enteric fever patients in tertiary care hospital, Kathmandu. BMC Microbiology, 2022, 22: 51. https://doi.org/10.1186/s12866-022-02456-7.
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