未经证实:布丁肠杆菌是一种新兴的人类病原体,其中已从各种环境中不断分离出多重耐药菌株。因此,这种生物有可能对人类健康构成挑战。然而,机制,尤其是外排泵,布甘迪氏菌中多药耐药性的原因仍有待很好地阐明。
未经鉴定:使用全基因组测序特异性鉴定肠杆菌菌株CMCC(B)45301。鉴定了在大肠杆菌中表征的TolC依赖性外排泵基因的特定CMCC(B)45301同源物。构建CMCC(B)45301中的tolC缺失突变体,并使用26种不同的抗微生物剂进行药敏试验,以及野生型菌株。测定了芽孢杆菌粗提物(BCE)和几种其它TolC影响的化合物对CMCC(B)45301的协同作用。
未经授权:我们将CMCC(B)45301肠杆菌菌株从泄殖腔菌种重新分类为布干根,基于其全基因组序列。我们发现CMCC(B)45301TolC,AcrAB,AcrD,AcrEF,MdtABC,EmrAB,和MacAB在大肠杆菌和阴沟肠杆菌中与它们各自的同源物表现出高度相似性。我们的药敏试验结果表明,缺乏tolC会导致哌拉西林的最低抑制浓度降低4至256倍,庆大霉素,卡那霉素,四环素,诺氟沙星,环丙沙星,氯霉素,和红霉素对CMCC(B)45301。此外,头孢呋辛形成的抑制区,头孢哌酮,阿米卡星,链霉素,米诺环素,多西环素,左氧氟沙星,氟苯尼考,甲氧苄啶-磺胺甲恶唑,阿奇霉素,林可霉素,tolC突变体的克林霉素比亲本更大或更明显。我们的数据表明,TolC在CMCC(B)45301对涵盖β-内酰胺的常见抗生素家族的敏感性中发挥了重要作用,氨基糖苷类,四环素,氟喹诺酮,苯酚,叶酸途径拮抗剂,大环内酯,还有lincosamide.删除tolC也增加了CMCC(B)45301对盐酸小檗碱和BCE的敏感性,两种基于天然产品的代理。最后,我们发现红霉素,诺氟沙星,环丙沙星可以增强BCE对CMCC(B)45301的抗菌活性。
UNASSIGNED:本研究阐述了TolC对布丁大肠杆菌抗菌药物敏感性的综合影响,这可能有助于开发针对这种医院病原体的更多治疗选择。
Enterobacter bugandensis is an emerging human pathogen in which multidrug resistant strains have been continuously isolated from various environments. Thus, this organism possesses the potential to pose challenges in human healthcare. However, the mechanisms, especially the efflux pumps, responsible for the multidrug resistance in E. bugandensis remain to be well elucidated.
The Enterobacter strain CMCC(B) 45301 was specifically identified using whole genome sequencing. The specific CMCC(B) 45301 homologues of the
TolC dependent efflux-pump genes characterized in Escherichia coli were identified. The
tolC deletion mutant in CMCC(B) 45301 was constructed and subjected to susceptibility tests using 26 different antimicrobial agents, along with the wild type strain. The synergistic effects combining the Bacillus crude extract (BCE) and several other TolC-affected compounds against CMCC(B) 45301 were assayed.
We reclassified the Enterobacter CMCC(B) 45301 strain from species cloacae to bugandensis, on the basis of its whole genome sequence. We found that the CMCC(B) 45301
TolC, AcrAB, AcrD, AcrEF, MdtABC, EmrAB, and MacAB exhibit high similarity with their respective homologues in E. coli and Enterobacter cloacae. Our results for the susceptibility tests revealed that lacking
tolC causes 4- to 256-fold decrease in the minimal inhibitory concentrations of piperacillin, gentamicin, kanamycin, tetracycline, norfloxacin, ciprofloxacin, chloramphenicol, and erythromycin against CMCC(B) 45301. In addition, the inhibition zones formed by cefuroxime, cefoperazone, amikacin, streptomycin, minocycline, doxycycline, levofloxacin, florfenicol, trimethoprim-sulfamethoxazole, azithromycin, lincomycin, and clindamycin for the tolC mutant were larger or more obvious than that for the parent. Our data suggested the important role played by TolC in CMCC(B) 45301 susceptibility to common antibiotic families covering ß-lactam, aminoglycoside, tetracycline, fluoroquinolone, phenicol, folate pathway antagonist, macrolide, and lincosamide. Deletion for
tolC also increased the susceptibility of CMCC(B) 45301 to berberine hydrochloride and BCE, two natural product-based agents. Finally, we found that erythromycin, norfloxacin, and ciprofloxacin can potentiate the antibacterial activity of BCE against CMCC(B) 45301.
The present study elaborated the comprehensive TolC effect on the antimicrobial susceptibility profile in E. bugandensis, which might contribute to the development of more therapeutic options against this nosocomial pathogen.