Khaleghi Moj, Khorrami Sadegh
Department of Biology, Faculty of Sciences, Shahid Bahonar University of Kerman, Kerman, Iran.
Research and Technology Institute of Plant Production, Shahid Bahonar University of Kerman, Kerman, Iran.
AMB Express. 2021 Jun 10;11(1):85. doi: 10.1186/s13568-021-01247-z.
Considering the prevalence of resistance to antibiotics, the discovery of effective agents against resistant pathogens is of extreme urgency. Herein, 26 mecA-positive methicillin-resistant S. aureus (MRSA) isolated from clinical samples were identified, and their resistance to 11 antibiotics was investigated. Next, the antibacterial and anti-biofilm activity of the ethanolic extract of M. communis on these strains was evaluated. Furthermore, the effect of this extract on the expression of biofilm-associated genes, icaA, icaD, bap, sarA, and agr, was studied. According to the results, all isolated strains were multidrug-resistant and showed resistance to oxacillin and tetracycline. Also, 96.15 and 88.46 % of them were resistant to gentamicin and erythromycin. However, the extract could effectively combat the strains. The minimum inhibitory concentration (MIC) against different strains ranged from 1.56 to 25 mg/ml and the minimum bactericidal concentration (MBC) was between 3.125 and 50 mg/ml. Even though most MRSA (67 %) strongly produced biofilm, the sub-MIC concentration of the extract destroyed the pre-formed biofilm and affected the bacterial cells inside the biofilm. It could also inhibit biofilm development by significantly decreasing the expression of icaA, icaD, sarA and bap genes involved in biofilm formation and development. In conclusion, the extract inhibits biofilm formation, ruins pre-formed biofilm, and kills cells living inside the biofilm. Furthermore, it down-regulates the expression of necessary genes and nips the biofilm formation in the bud.
鉴于抗生素耐药性的普遍存在，发现针对耐药病原体的有效药物迫在眉睫。在此，从临床样本中鉴定出26株mecA阳性耐甲氧西林金黄色葡萄球菌（MRSA），并研究了它们对11种抗生素的耐药性。接下来，评估了小茴香乙醇提取物对这些菌株的抗菌和抗生物膜活性。此外，还研究了该提取物对生物膜相关基因icaA、icaD、bap、sarA和agr表达的影响。根据结果，所有分离菌株均为多重耐药，对苯唑西林和四环素耐药。此外，96.15%和88.46%的菌株对庆大霉素和红霉素耐药。然而，该提取物可以有效对抗这些菌株。对不同菌株的最低抑菌浓度（MIC）范围为1.56至25mg/ml，最低杀菌浓度（MBC）在3.125至50mg/ml之间。尽管大多数MRSA（67%）强烈产生生物膜，但提取物的亚MIC浓度可破坏预先形成的生物膜，并影响生物膜内的细菌细胞。它还可以通过显著降低参与生物膜形成和发育的icaA、icaD、sarA和bap基因的表达来抑制生物膜的形成。总之，该提取物可抑制生物膜形成，破坏预先形成的生物膜，并杀死生物膜内的细胞。此外，它下调必需基因的表达，将生物膜形成扼杀在萌芽状态。
