Research Unit of Analysis and Process Applied on the Environment UR17ES32 ISSAT- 5121 Mahdia, University of Monastir, Monastir, Tunisia.
BioMorf Department, University of Messina, Polo SS Annunziata, 98168, Messina, Italy.
Arch Microbiol. 2022 Mar 30;204(4):229. doi: 10.1007/s00203-022-02842-9.
Faced with the significant disturbances, mainly of anthropogenic origin, which affect the Mediterranean coastal ecosystem, Posidonia oceanica (L.) Delile has often been used to assess the state of health of this environment. The present study aims to determine the multidrug resistance patterns among isolated and identified epi-endophytic bacterial strains in P. oceanica seagrass collected from Mahdia coastal seawater (Tunisia). To investigate the bacterial community structure and diversity from coastal seawater samples from Mahdia, total DNA extraction and 16S rRNA gene amplification were performed and analyzed by denaturing gradient gel electrophoresis (DGGE). The DGGE profiles showed that some bands were specific to a given site, while other bands were found to be common to more than one sample. In the other hand, bacterial strains were isolated from 1 mL of leaves and epiphytes suspension of P. oceanica seagrass in marine agar. Forty-three isolates were obtained, seven of them were selected and identified on the basis of 16S rRNA gene sequence analysis. These isolates belonged to the genus Bacillus, exhibiting 98-100% of identity with known sequences. Susceptibility patterns of these strains were studied toward commonly used antibiotics in Tunisia. All identified isolates were resistant to Aztreonam (72.1%), Ceftazidime (60.5%), Amoxicillin (56%) and Rifampicin (51.2%). S5-L13 strain had presented the highest multidrug resistance with a MAR index of 0.67.
面对影响地中海沿海生态系统的重大干扰，主要是人为造成的干扰，波西多尼亚海草（Posidonia oceanica (L.) Delile）经常被用来评估该环境的健康状况。本研究旨在确定从突尼斯马赫迪亚沿海海域采集的波西多尼亚海草内生细菌分离株和鉴定的内生细菌的多药耐药模式。为了研究马赫迪亚沿海海水样本中的细菌群落结构和多样性，进行了总 DNA 提取和 16S rRNA 基因扩增，并通过变性梯度凝胶电泳（DGGE）进行分析。DGGE 图谱显示，一些条带是特定于给定地点的，而其他条带则发现存在于多个样品中。另一方面，从波西多尼亚海草叶片和附生微生物悬浮液的 1 mL 中分离出细菌菌株在海洋琼脂中。获得了 43 个分离株，其中 7 个根据 16S rRNA 基因序列分析进行了选择和鉴定。这些分离株属于芽孢杆菌属，与已知序列的同源性为 98-100%。研究了这些菌株对突尼斯常用抗生素的药敏模式。所有鉴定的分离株对氨曲南（72.1%）、头孢他啶（60.5%）、阿莫西林（56%）和利福平（51.2%）具有耐药性。S5-L13 菌株的 MAR 指数为 0.67，表现出最高的多药耐药性。
