Gestels, Z.; Abdellati, S.; Kenyon, C.; Manoharan-Basil, S.S. Ciprofloxacin Concentrations 100-Fold Lower than the MIC Can Select for Ciprofloxacin Resistance in Neisseria subflava: An In Vitro Study. Antibiotics2024, 13, 560.
Gestels, Z.; Abdellati, S.; Kenyon, C.; Manoharan-Basil, S.S. Ciprofloxacin Concentrations 100-Fold Lower than the MIC Can Select for Ciprofloxacin Resistance in Neisseria subflava: An In Vitro Study. Antibiotics 2024, 13, 560.
Gestels, Z.; Abdellati, S.; Kenyon, C.; Manoharan-Basil, S.S. Ciprofloxacin Concentrations 100-Fold Lower than the MIC Can Select for Ciprofloxacin Resistance in Neisseria subflava: An In Vitro Study. Antibiotics2024, 13, 560.
Gestels, Z.; Abdellati, S.; Kenyon, C.; Manoharan-Basil, S.S. Ciprofloxacin Concentrations 100-Fold Lower than the MIC Can Select for Ciprofloxacin Resistance in Neisseria subflava: An In Vitro Study. Antibiotics 2024, 13, 560.
Abstract
Background
Neisseria gonorrhoeae can acquire antimicrobial resistance (AMR) through horizontal gene transfer (HGT) from other Neisseria spp. such as commensals like Neisseria subflava. The prevalence of Neisseria subflava in the oropharynx is close to 100%. Low doses of antimicrobials in food could select for AMR in N. subflava, which could then be transferred to N. gonorrhoeae. In this study, we aimed to determine the lowest concentration of ciprofloxacin that can induce ciprofloxacin resistance (minimum selection concentration – MSC) in N. subflava.
Methods
Neisseria subflava Co000790/2 was serially passaged on GC agar plates containing ciprofloxacin concentrations ranging from 1:100- to 1:10,000-below its ciprofloxacin MIC (0.006 µg/ml) for six days.
Results
After 6 days of serial passaging at ciprofloxacin concentrations 1/100th of the MIC, 24 colonies emerged on the 0.06 µg/ml ciprofloxacin plate. Their ciprofloxacin MICs were between 0.19 to 0.25 µg/ml, and whole genome sequencing revealed a missense mutation T91I in the gyrA gene, which has previously been found to cause reduced susceptibility to fluoroquinolones.
Conclusion
The N. subflava MSCde novo was determined to be 0.06 ng/mL or 1:100 below the MIC. The implications of this finding are that the low concentrations of antibiotics found in certain environmental samples and even the food we eat may be able to select for ciprofloxacin resistance in N. subflava.
Biology and Life Sciences, Immunology and Microbiology
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
