PDF(Pubmed)
Abstract：
Neisseria gonorrhoeae can acquire antimicrobial resistance (AMR) through horizontal gene transfer (HGT) from other Neisseria spp. such as commensals like Neisseria subflava. 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 a N. subflava isolate (ID-Co000790/2, a clinical isolate collected from a previous community study conducted at ITM). In this study, Neisseria subflava was serially passaged on gonococcal (GC) medium agar plates containing ciprofloxacin concentrations ranging from 1:100 to 1:10,000 below its ciprofloxacin MIC (0.006 µg/mL) for 6 days. After 6 days of serial passaging at ciprofloxacin concentrations of 1/100th of the MIC, 24 colonies emerged on the plate containing 0.06 µg/mL ciprofloxacin, which corresponds to the EUCAST breakpoint for N. gonorrhoeae. 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. The N. subflava MSCde novo was determined to be 0.06 ng/mL (0.00006 µg/mL), which is 100×-fold lower than the ciprofloxacin MIC. The implications of this finding are that the low concentrations of fluoroquinolones found in certain environmental samples, such as soil, river water, and even the food we eat, may be able to select for ciprofloxacin resistance in N. subflava.
摘要：
淋病奈瑟菌可以通过水平基因转移（HGT）从其他奈瑟菌获得抗菌素耐药性（AMR）。例如亚黄奈瑟氏菌等共生体。食物中低剂量的抗微生物剂可以选择N.subflava中的AMR，然后可以转移到淋病奈瑟菌。在这项研究中,我们的目的是确定能够诱导环丙沙星耐药的环丙沙星的最低浓度(最低选择浓度-MSC)。在这项研究中,在淋球菌（GC）培养基琼脂平板上连续传代，其中环丙沙星的浓度范围为1：100至1：10,000，低于其环丙沙星MIC（0.006µg/mL），持续6天。环丙沙星浓度为MIC的1/100时连续传代6天后，24个菌落出现在含有0.06µg/mL环丙沙星的平板上，对应于淋病奈瑟菌的EUCAST断点。他们的环丙沙星MIC在0.19至0.25微克/毫升之间，全基因组测序显示gyrA基因有一个错义突变T91I,先前已发现可降低对氟喹诺酮类药物的敏感性。N.subflavaMSCdenovo被确定为0.06ng/mL（0.00006µg/mL），比环丙沙星MIC低100倍。这一发现的含义是，在某些环境样品中发现低浓度的氟喹诺酮类药物，比如土壤,河水,甚至我们吃的食物，可以选择亚黄奈瑟菌对环丙沙星的耐药性。
